1
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Zong J, Christensen KE, Robertson J. Routes to Advanced Intermediates in the Synthesis of Tetracarbocyclic Sesquiterpenoids Daphnenoid A and Artatrovirenols A and B. Org Lett 2024; 26:1556-1560. [PMID: 38373293 PMCID: PMC10913076 DOI: 10.1021/acs.orglett.3c04199] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2023] [Revised: 01/19/2024] [Accepted: 02/14/2024] [Indexed: 02/21/2024]
Abstract
A short route from dihydrocarvone is described, which led to the tetracarbocyclic core common to artatrovirenol A and B and daphnenoid A. A variant of this route afforded guaia-4,6-dien-3-one (from Enterospermum madagascarensis) and its epimer. From 2-(2-oxoethyl)furan, a 15-step sequence then delivered the complete carbon skeleton and all functionality necessary for daphnenoid A. Key steps in the route include diastereoselective intramolecular oxidopyrylium cycloaddition, oxa-bridge cleavage under "push-pull" conditions, and intramolecular Diels-Alder cycloaddition.
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Affiliation(s)
- Jiarui Zong
- Department of Chemistry, University
of Oxford, Chemistry Research
Laboratory, Mansfield Road, Oxford OX1 3TA, United Kingdom
| | - Kirsten E. Christensen
- Department of Chemistry, University
of Oxford, Chemistry Research
Laboratory, Mansfield Road, Oxford OX1 3TA, United Kingdom
| | - Jeremy Robertson
- Department of Chemistry, University
of Oxford, Chemistry Research
Laboratory, Mansfield Road, Oxford OX1 3TA, United Kingdom
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2
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McNamee RE, Frank N, Christensen KE, Duarte F, Anderson EA. Taming nonclassical carbocations to control small ring reactivity. Sci Adv 2024; 10:eadj9695. [PMID: 38215201 PMCID: PMC10786418 DOI: 10.1126/sciadv.adj9695] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Accepted: 12/13/2023] [Indexed: 01/14/2024]
Abstract
Prediction of the outcome of ring opening of small organic rings under cationic conditions can be challenging due to the intermediacy of nonclassical carbocations. For example, the solvolysis of cyclobutyl or cyclopropylmethyl derivatives generates up to four products on nucleophilic capture or elimination via cyclopropylcarbinyl and bicyclobutonium ions. Here, we show that such reaction outcomes can be controlled by subtle changes to the structure of nonclassical carbocation. Using bicyclo[1.1.0]butanes as cation precursors, the regio- and stereochemistry of ring opening is shown to depend on the degree and nature of the substituents on the cationic intermediates. Reaction outcomes are rationalized using computational models, resulting in a flowchart to predict product formation from a given cation precursor.
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Affiliation(s)
| | | | | | - Fernanda Duarte
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, UK
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3
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McNamee RE, Dasgupta A, Christensen KE, Anderson EA. Bridge Cross-Coupling of Bicyclo[1.1.0]butanes. Org Lett 2024; 26:360-364. [PMID: 38156902 PMCID: PMC10789093 DOI: 10.1021/acs.orglett.3c04030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Revised: 12/20/2023] [Accepted: 12/20/2023] [Indexed: 01/03/2024]
Abstract
Bicyclo[1.1.0]butanes (BCBs) have gained growing popularity in "strain release" chemistry for the synthesis of four-membered-ring systems and para- and meta-disubstituted arene bioisosteres as well as applications in chemoselective bioconjugation. However, functionalization of the bridge position of BCBs can be challenging due to the inherent strain of the ring system and reactivity of the central C-C bond. Here we report the first late-stage bridge cross-coupling of BCBs, mediated by directed metalation/palladium catalysis.
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Affiliation(s)
- Ryan E. McNamee
- Chemistry Research Laboratory,
Department of Chemistry, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, U.K.
| | - Ayan Dasgupta
- Chemistry Research Laboratory,
Department of Chemistry, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, U.K.
| | - Kirsten E. Christensen
- Chemistry Research Laboratory,
Department of Chemistry, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, U.K.
| | - Edward A. Anderson
- Chemistry Research Laboratory,
Department of Chemistry, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, U.K.
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4
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Dasgupta A, Bhattacharjee S, Tong Z, Guin A, McNamee RE, Christensen KE, Biju AT, Anderson EA. Stereoselective Alder-Ene Reactions of Bicyclo[1.1.0]butanes: Facile Synthesis of Cyclopropyl- and Aryl-Substituted Cyclobutenes. J Am Chem Soc 2024; 146:1196-1203. [PMID: 38157245 PMCID: PMC10786042 DOI: 10.1021/jacs.3c13080] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2023] [Revised: 12/14/2023] [Accepted: 12/15/2023] [Indexed: 01/03/2024]
Abstract
Bicyclo[1.1.0]butanes (BCBs), strained carbocycles comprising two fused cyclopropane rings, have become well-established building blocks in organic synthesis, medicinal chemistry, and chemical biology due to their diverse reactivity profile with radicals, nucleophiles, cations, and carbenes. The constraints of the bicyclic ring system confer high p-character on the interbridgehead C-C bond, leading to this broad reaction profile; however, the use of BCBs in pericyclic processes has to date been largely overlooked in favor of such stepwise, non-concerted additions. Here, we describe the use of BCBs as substrates for ene-like reactions with strained alkenes and alkynes, which give rise to cyclobutenes decorated with highly substituted cyclopropanes and arenes. The former products are obtained from highly stereoselective reactions with cyclopropenes, generated in situ from vinyl diazoacetates under blue light irradiation (440 nm). Cyclobutenes featuring a quaternary aryl-bearing carbon atom are prepared from equivalent reactions with arynes, which proceed in high yields under mild conditions. Mechanistic studies highlight the importance of electronic effects in this chemistry, while computational investigations support a concerted pathway and rationalize the excellent stereoselectivity of reactions with cyclopropenes.
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Affiliation(s)
- Ayan Dasgupta
- Chemistry
Research Laboratory, Department of Chemistry, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, U.K.
| | - Subrata Bhattacharjee
- Department
of Organic Chemistry, Indian Institute of
Science, Bangalore 560012, India
| | - Zixuan Tong
- Chemistry
Research Laboratory, Department of Chemistry, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, U.K.
| | - Avishek Guin
- Department
of Organic Chemistry, Indian Institute of
Science, Bangalore 560012, India
| | - Ryan E. McNamee
- Chemistry
Research Laboratory, Department of Chemistry, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, U.K.
| | - Kirsten E. Christensen
- Chemistry
Research Laboratory, Department of Chemistry, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, U.K.
| | - Akkattu T. Biju
- Department
of Organic Chemistry, Indian Institute of
Science, Bangalore 560012, India
| | - Edward A. Anderson
- Chemistry
Research Laboratory, Department of Chemistry, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, U.K.
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5
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Bąk K, Marques I, Kuhn H, Christensen KE, Félix V, Beer PD. Fullerene-Functionalized Halogen-Bonding Heteroditopic Hosts for Ion-Pair Recognition. J Am Chem Soc 2023; 145:27367-27379. [PMID: 38060428 PMCID: PMC10739994 DOI: 10.1021/jacs.3c07774] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2023] [Revised: 11/02/2023] [Accepted: 11/06/2023] [Indexed: 12/21/2023]
Abstract
Despite their hydrophobic surfaces with localized π-holes and rigid well-defined architectures providing a scaffold for preorganizing binding motifs, fullerenes remain unexplored as potential supramolecular host platforms for the recognition of anions. Herein, we present the first example of the rational design, synthesis, and unique recognition properties of novel fullerene-functionalized halogen-bonding (XB) heteroditopic ion-pair receptors containing cation and anion binding domains spatially separated by C60. Fullerene spatial separation of the XB donors and the crown ether complexed potassium cation resulted in a rare example of an artificial receptor containing two anion binding sites with opposing preferences for hard and soft halides. Importantly, the incorporation of the C60 motif into the heteroditopic receptor structure has a significant effect on the halide binding selectivity, which is further amplified upon K+ cation binding. The potassium cation complexed fullerene-based receptors exhibit enhanced selectivity for the soft polarizable iodide ion which is assisted by the C60 scaffold preorganizing the potent XB-based binding domains, anion-π interactions, and the exceptional polarizability of the fullerene moiety, as evidenced from DFT calculations. These observations serve to highlight the unique properties of fullerene surfaces for proximal charged guest binding with potential applications in construction of selective molecular sensors and modulating the properties of solar cell devices.
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Affiliation(s)
- Krzysztof
M. Bąk
- Chemistry
Research Laboratory, Department of Chemistry, University of Oxford, Oxford OX1 3TA, U.K.
| | - Igor Marques
- CICECO
- Aveiro Institute of Materials, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal
| | - Heike Kuhn
- Chemistry
Research Laboratory, Department of Chemistry, University of Oxford, Oxford OX1 3TA, U.K.
| | - Kirsten E. Christensen
- Chemistry
Research Laboratory, Department of Chemistry, University of Oxford, Oxford OX1 3TA, U.K.
| | - Vítor Félix
- CICECO
- Aveiro Institute of Materials, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal
| | - Paul D. Beer
- Chemistry
Research Laboratory, Department of Chemistry, University of Oxford, Oxford OX1 3TA, U.K.
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6
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Harwood LA, Xiong Z, Christensen KE, Wang R, Wong LL, Robertson J. Selective P450 BM3 Hydroxylation of Cyclobutylamine and Bicyclo[1.1.1]pentylamine Derivatives: Underpinning Synthetic Chemistry for Drug Discovery. J Am Chem Soc 2023; 145:27767-27773. [PMID: 38051939 PMCID: PMC10740007 DOI: 10.1021/jacs.3c10542] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2023] [Revised: 11/13/2023] [Accepted: 11/15/2023] [Indexed: 12/07/2023]
Abstract
Achieving single-step syntheses of a set of related compounds divergently and selectively from a common starting material affords substantial efficiency gains when compared with preparing those same compounds by multiple individual syntheses. In order for this approach to be realized, complementary reagent systems must be available; here, a panel of engineered P450BM3 enzymes is shown to fulfill this remit in the selective C-H hydroxylation of cyclobutylamine derivatives at chemically unactivated sites. The oxidations can proceed with high regioselectivity and stereoselectivity, producing valuable bifunctional intermediates for synthesis and applications in fragment-based drug discovery. The process also applies to bicyclo[1.1.1]pentyl (BCP) amine derivatives to achieve the first direct enantioselective functionalization of the bridging methylenes and open a short and efficient route to chiral BCP bioisosteres for medicinal chemistry. The combination of substrate, enzyme, and reaction engineering provides a powerful general platform for small-molecule elaboration and diversification.
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Affiliation(s)
- Lucy A. Harwood
- Chemistry
Research Laboratory, Department of Chemistry, University of Oxford, Mansfield Road, Oxford OX1 3TA, U.K.
| | - Ziyue Xiong
- Oxford
Suzhou Centre for Advanced Research, Ruo Shui Road, Suzhou Industrial Park, Suzhou, Jiangsu 215123, P. R. China
| | - Kirsten E. Christensen
- Chemistry
Research Laboratory, Department of Chemistry, University of Oxford, Mansfield Road, Oxford OX1 3TA, U.K.
| | - Ruiyao Wang
- Wisdom
Lake Academy of Pharmacy, Xi’an Jiaotong-Liverpool
University, Suzhou Industrial
Park, Suzhou, Jiangsu, 215123, P. R. China
| | - Luet L. Wong
- Oxford
Suzhou Centre for Advanced Research, Ruo Shui Road, Suzhou Industrial Park, Suzhou, Jiangsu 215123, P. R. China
- Inorganic
Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QR, U.K.
| | - Jeremy Robertson
- Chemistry
Research Laboratory, Department of Chemistry, University of Oxford, Mansfield Road, Oxford OX1 3TA, U.K.
- Oxford
Suzhou Centre for Advanced Research, Ruo Shui Road, Suzhou Industrial Park, Suzhou, Jiangsu 215123, P. R. China
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7
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Tong Z, Smith PJ, Pickford HD, Christensen KE, Anderson EA. Gold-Catalyzed Cyclization of Yndiamides with Isoxazoles via α-Imino Gold Fischer Carbenes. Chemistry 2023; 29:e202302821. [PMID: 37767940 PMCID: PMC10947298 DOI: 10.1002/chem.202302821] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Revised: 09/27/2023] [Accepted: 09/28/2023] [Indexed: 09/29/2023]
Abstract
Gold catalysis is an important method for alkyne functionalization. Here we report the gold-catalyzed formal [3+2] aminative cyclization of yndiamides and isoxazoles in a direct synthesis of polysubstituted diaminopyrroles, which are important motifs in drug discovery. Key to this process is the formation, and subsequent cyclization, of an α-imino gold Fischer carbene, which represents a new type of gold carbene intermediate. The reaction proceeds rapidly under mild conditions, with high regioselectivity being achieved by introducing a subtle steric bias between the nitrogen substituents on the yndiamide. DFT calculations revealed that the key to this regioselectivity was the interconversion of isomeric gold keteniminiun ions via a low-barrier π-complex transition state, which establishes a Curtin-Hammett scenario for isoxazole addition. By using benzisoxazoles as substrates, the reaction outcome could be switched to a formal [5+2] cyclization, leading to 1,4-oxazepines.
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Affiliation(s)
- Zixuan Tong
- Chemistry Research LaboratoryDepartment of ChemistryUniversity of Oxford12 Mansfield RoadOxfordOX1 3TAUK
| | - Philip J. Smith
- Chemistry Research LaboratoryDepartment of ChemistryUniversity of Oxford12 Mansfield RoadOxfordOX1 3TAUK
| | - Helena D. Pickford
- Chemistry Research LaboratoryDepartment of ChemistryUniversity of Oxford12 Mansfield RoadOxfordOX1 3TAUK
| | - Kirsten E. Christensen
- Chemistry Research LaboratoryDepartment of ChemistryUniversity of Oxford12 Mansfield RoadOxfordOX1 3TAUK
| | - Edward A. Anderson
- Chemistry Research LaboratoryDepartment of ChemistryUniversity of Oxford12 Mansfield RoadOxfordOX1 3TAUK
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8
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Poh CYX, Rozsar D, Yang J, Christensen KE, Dixon DJ. Bifunctional Iminophosphorane Catalyzed Amide Enolization for Enantioselective Cyclohexadienone Desymmetrization. Angew Chem Int Ed Engl 2023:e202315401. [PMID: 38055190 DOI: 10.1002/anie.202315401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2023] [Revised: 11/29/2023] [Accepted: 11/30/2023] [Indexed: 12/07/2023]
Abstract
The organocatalytic enolization of 2-arylacetamides, followed by an enantioselective intramolecular conjugate addition to tethered 2,5-cyclohexadienones, yielding 3D fused N-heterocycles, is described. The transformation represents the first strong activating group-free activation of carboxamides via α-C-H deprotonation in a metal-free, catalytic, and enantioselective reaction, and is achieved by employing a bifunctional iminophosphorane (BIMP) superbase.
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Affiliation(s)
- Charmaine Y X Poh
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory, Oxford, UK
| | - Daniel Rozsar
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory, Oxford, UK
| | - Jinchao Yang
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory, Oxford, UK
| | - Kirsten E Christensen
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory, Oxford, UK
| | - Darren J Dixon
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory, Oxford, UK
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9
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Gao Y, Albrecht F, Rončević I, Ettedgui I, Kumar P, Scriven LM, Christensen KE, Mishra S, Righetti L, Rossmannek M, Tavernelli I, Anderson HL, Gross L. On-surface synthesis of a doubly anti-aromatic carbon allotrope. Nature 2023; 623:977-981. [PMID: 37880363 PMCID: PMC10686826 DOI: 10.1038/s41586-023-06566-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Accepted: 08/23/2023] [Indexed: 10/27/2023]
Abstract
Synthetic carbon allotropes such as graphene1, carbon nanotubes2 and fullerenes3 have revolutionized materials science and led to new technologies. Many hypothetical carbon allotropes have been discussed4, but few have been studied experimentally. Recently, unconventional synthetic strategies such as dynamic covalent chemistry5 and on-surface synthesis6 have been used to create new forms of carbon, including γ-graphyne7, fullerene polymers8, biphenylene networks9 and cyclocarbons10,11. Cyclo[N]carbons are molecular rings consisting of N carbon atoms12,13; the three that have been reported to date (N = 10, 14 and 18)10,11 are doubly aromatic, which prompts the question: is it possible to prepare doubly anti-aromatic versions? Here we report the synthesis and characterization of an anti-aromatic carbon allotrope, cyclo[16]carbon, by using tip-induced on-surface chemistry6. In addition to structural information from atomic force microscopy, we probed its electronic structure by recording orbital density maps14 with scanning tunnelling microscopy. The observation of bond-length alternation in cyclo[16]carbon confirms its double anti-aromaticity, in concordance with theory. The simple structure of C16 renders it an interesting model system for studying the limits of aromaticity, and its high reactivity makes it a promising precursor to novel carbon allotropes15.
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Affiliation(s)
- Yueze Gao
- Department of Chemistry, Oxford University, Chemistry Research Laboratory, Oxford, UK
| | | | - Igor Rončević
- Department of Chemistry, Oxford University, Chemistry Research Laboratory, Oxford, UK
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Prague, Czechia
| | - Isaac Ettedgui
- Department of Chemistry, Oxford University, Chemistry Research Laboratory, Oxford, UK
| | - Paramveer Kumar
- Department of Chemistry, Oxford University, Chemistry Research Laboratory, Oxford, UK
| | - Lorel M Scriven
- Department of Chemistry, Oxford University, Chemistry Research Laboratory, Oxford, UK
| | - Kirsten E Christensen
- Department of Chemistry, Oxford University, Chemistry Research Laboratory, Oxford, UK
| | | | - Luca Righetti
- IBM Quantum, IBM Research - Zürich, Rüschlikon, Switzerland
| | - Max Rossmannek
- IBM Quantum, IBM Research - Zürich, Rüschlikon, Switzerland
| | | | - Harry L Anderson
- Department of Chemistry, Oxford University, Chemistry Research Laboratory, Oxford, UK.
| | - Leo Gross
- IBM Research Europe - Zürich, Rüschlikon, Switzerland.
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10
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de Munnik M, Lithgow J, Brewitz L, Christensen KE, Bates RH, Rodriguez-Miquel B, Schofield CJ. αβ,α'β'-Diepoxyketones are mechanism-based inhibitors of nucleophilic cysteine enzymes. Chem Commun (Camb) 2023; 59:12859-12862. [PMID: 37815791 PMCID: PMC10601815 DOI: 10.1039/d3cc02932h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2023] [Accepted: 09/30/2023] [Indexed: 10/11/2023]
Abstract
Epoxides are an established class of electrophilic alkylating agents that react with nucleophilic protein residues. We report αβ,α'β'-diepoxyketones (DEKs) as a new type of mechanism-based inhibitors of nucleophilic cysteine enzymes. Studies with the L,D-transpeptidase LdtMt2 from Mycobacterium tuberculosis and the main protease from SARS-CoV-2 (Mpro) reveal that following epoxide ring opening by a nucleophilic cysteine, further reactions can occur, leading to irreversible alkylation.
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Affiliation(s)
- Mariska de Munnik
- Chemistry Research Laboratory, Department of Chemistry and the Ineos Oxford Institute of Antimicrobial Research, University of Oxford, 12 Mansfield Road, Oxford, OX1 3TA, UK.
| | - Jasper Lithgow
- Chemistry Research Laboratory, Department of Chemistry and the Ineos Oxford Institute of Antimicrobial Research, University of Oxford, 12 Mansfield Road, Oxford, OX1 3TA, UK.
| | - Lennart Brewitz
- Chemistry Research Laboratory, Department of Chemistry and the Ineos Oxford Institute of Antimicrobial Research, University of Oxford, 12 Mansfield Road, Oxford, OX1 3TA, UK.
| | - Kirsten E Christensen
- Chemical Crystallography, Chemistry Research Laboratory, Department of Chemistry, University of Oxford, 12 Mansfield Road, Oxford, OX1 3TA, UK
| | - Robert H Bates
- Tres Cantos Medicines Development Campus, GlaxoSmithKline, Calle Severo Ochoa 2, Tres Cantos, Madrid, Spain
| | - Beatriz Rodriguez-Miquel
- Tres Cantos Medicines Development Campus, GlaxoSmithKline, Calle Severo Ochoa 2, Tres Cantos, Madrid, Spain
| | - Christopher J Schofield
- Chemistry Research Laboratory, Department of Chemistry and the Ineos Oxford Institute of Antimicrobial Research, University of Oxford, 12 Mansfield Road, Oxford, OX1 3TA, UK.
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11
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Andrews J, Kalepu J, Palmer CF, Poole DL, Christensen KE, Willis MC. Photocatalytic Carboxylate to Sulfinamide Switching Delivers a Divergent Synthesis of Sulfonamides and Sulfonimidamides. J Am Chem Soc 2023; 145:21623-21629. [PMID: 37738304 PMCID: PMC10557147 DOI: 10.1021/jacs.3c07974] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Indexed: 09/24/2023]
Abstract
sulfinamides, sulfonamides, and sulfonimidamides are in-demand motifs in medicinal chemistry, yet methods for the synthesis of alkyl variants that start from simple, readily available feedstocks are scarce. In addition, bespoke syntheses of each class of molecules are usually needed. In this report, we detail the synthesis of these three distinct sulfur functional groups, using readily available and structurally diverse alkyl carboxylic acids as the starting materials. The method harnesses alkyl radical generation from carboxylic acids using acridine photocatalysts and 400 nm light with subsequent radical addition to sulfinylamine reagents, delivering sulfinamide products. Using the N-alkoxy sulfinylamine reagent t-BuO-NSO as the radical trap provides common N-alkoxy sulfinamide intermediates, which can be converted in a divergent manner to either sulfonamides or sulfonimidamides, by treatment with sodium hydroxide, or an amine, respectively. The reactions are scalable, tolerate a broad range of functional groups, and can be used for the diversification of complex biologically active compounds.
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Affiliation(s)
- Jonathan
A. Andrews
- Department
of Chemistry, University of Oxford, Mansfield Road, Oxford OX1 3TA, U.K.
| | - Jagadeesh Kalepu
- Department
of Chemistry, University of Oxford, Mansfield Road, Oxford OX1 3TA, U.K.
| | | | - Darren L. Poole
- GlaxoSmithKline
Medicines Research Centre, Gunnels Wood Road, Stevenage, SG1 2NY, U.K.
| | | | - Michael C. Willis
- Department
of Chemistry, University of Oxford, Mansfield Road, Oxford OX1 3TA, U.K.
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12
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Brewitz L, Nakashima Y, Piasecka SK, Salah E, Fletcher SC, Tumber A, Corner TP, Kennedy TJ, Fiorini G, Thalhammer A, Christensen KE, Coleman ML, Schofield CJ. 5-Substituted Pyridine-2,4-dicarboxylate Derivatives Have Potential for Selective Inhibition of Human Jumonji-C Domain-Containing Protein 5. J Med Chem 2023; 66:10849-10865. [PMID: 37527664 PMCID: PMC10424186 DOI: 10.1021/acs.jmedchem.3c01114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Indexed: 08/03/2023]
Abstract
Jumonji-C domain-containing protein 5 (JMJD5) is a 2-oxoglutarate (2OG)-dependent oxygenase that plays important roles in development, circadian rhythm, and cancer through unclear mechanisms. JMJD5 has been reported to have activity as a histone protease, as an Nε-methyl lysine demethylase, and as an arginine residue hydroxylase. Small-molecule JMJD5-selective inhibitors will be useful for investigating its (patho)physiological roles. Following the observation that the broad-spectrum 2OG oxygenase inhibitor pyridine-2,4-dicarboxylic acid (2,4-PDCA) is a 2OG-competing JMJD5 inhibitor, we report that 5-aminoalkyl-substituted 2,4-PDCA derivatives are potent JMJD5 inhibitors manifesting selectivity for JMJD5 over other human 2OG oxygenases. Crystallographic analyses with five inhibitors imply induced fit binding and reveal that the 2,4-PDCA C5 substituent orients into the JMJD5 substrate-binding pocket. Cellular studies indicate that the lead compounds display similar phenotypes as reported for clinically observed JMJD5 variants, which have a reduced catalytic activity compared to wild-type JMJD5.
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Affiliation(s)
- Lennart Brewitz
- Chemistry
Research Laboratory, Department of Chemistry and the Ineos Oxford
Institute for Antimicrobial Research, University
of Oxford, 12 Mansfield Road, OX1 3TA Oxford, U.K.
| | - Yu Nakashima
- Chemistry
Research Laboratory, Department of Chemistry and the Ineos Oxford
Institute for Antimicrobial Research, University
of Oxford, 12 Mansfield Road, OX1 3TA Oxford, U.K.
| | - Sonia K. Piasecka
- Institute
of Cancer and Genomic Sciences, University
of Birmingham, Edgbaston, B15 2TT Birmingham, U.K.
| | - Eidarus Salah
- Chemistry
Research Laboratory, Department of Chemistry and the Ineos Oxford
Institute for Antimicrobial Research, University
of Oxford, 12 Mansfield Road, OX1 3TA Oxford, U.K.
| | - Sally C. Fletcher
- Institute
of Cancer and Genomic Sciences, University
of Birmingham, Edgbaston, B15 2TT Birmingham, U.K.
| | - Anthony Tumber
- Chemistry
Research Laboratory, Department of Chemistry and the Ineos Oxford
Institute for Antimicrobial Research, University
of Oxford, 12 Mansfield Road, OX1 3TA Oxford, U.K.
| | - Thomas P. Corner
- Chemistry
Research Laboratory, Department of Chemistry and the Ineos Oxford
Institute for Antimicrobial Research, University
of Oxford, 12 Mansfield Road, OX1 3TA Oxford, U.K.
| | - Tristan J. Kennedy
- Institute
of Cancer and Genomic Sciences, University
of Birmingham, Edgbaston, B15 2TT Birmingham, U.K.
| | - Giorgia Fiorini
- Chemistry
Research Laboratory, Department of Chemistry and the Ineos Oxford
Institute for Antimicrobial Research, University
of Oxford, 12 Mansfield Road, OX1 3TA Oxford, U.K.
| | - Armin Thalhammer
- Chemistry
Research Laboratory, Department of Chemistry and the Ineos Oxford
Institute for Antimicrobial Research, University
of Oxford, 12 Mansfield Road, OX1 3TA Oxford, U.K.
| | - Kirsten E. Christensen
- Chemical
Crystallography, Chemistry Research Laboratory, Department of Chemistry, University of Oxford, 12 Mansfield Road, OX1 3TA Oxford, U.K.
| | - Mathew L. Coleman
- Institute
of Cancer and Genomic Sciences, University
of Birmingham, Edgbaston, B15 2TT Birmingham, U.K.
| | - Christopher J. Schofield
- Chemistry
Research Laboratory, Department of Chemistry and the Ineos Oxford
Institute for Antimicrobial Research, University
of Oxford, 12 Mansfield Road, OX1 3TA Oxford, U.K.
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13
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Crompton JL, Frost JR, Rowe SM, Christensen KE, Donohoe TJ. Synthesis of Cyclopropanes via Hydrogen-Borrowing Catalysis. Org Lett 2023. [PMID: 37428545 PMCID: PMC10367074 DOI: 10.1021/acs.orglett.3c01768] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/11/2023]
Abstract
Cyclopropanes are highly useful motifs that are often incorporated into drug candidates to improve potency, metabolic stability, or pharmacokinetic properties. An expedient method for the α-cyclopropanation of ketones using hydrogen borrowing (HB) catalysis is described. The transformation occurs via HB alkylation of a hindered ketone with subsequent intramolecular displacement of a pendant leaving group affording the cyclopropanated product. The leaving group can be installed in either the ketone or alcohol component of the HB system, giving access to α-cyclopropyl ketones via two complementary approaches. Conversion to the corresponding carboxylic acids can be achieved in a simple two-step sequence to afford synthetically useful 1,1-substituted spirocyclopropyl acid building blocks.
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Affiliation(s)
- Jessica L Crompton
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory, Mansfield Road, Oxford, OX1 3TA, U.K
| | - James R Frost
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory, Mansfield Road, Oxford, OX1 3TA, U.K
| | - Sam M Rowe
- GSK Medicines Research Centre, Gunnels Wood Road, Stevenage, Hertfordshire SG1 2NY, U.K
| | - Kirsten E Christensen
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory, Mansfield Road, Oxford, OX1 3TA, U.K
| | - Timothy J Donohoe
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory, Mansfield Road, Oxford, OX1 3TA, U.K
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14
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Zhu H, Chen Q, Rončević I, Christensen KE, Anderson HL. Anthracene-Porphyrin Nanoribbons. Angew Chem Int Ed Engl 2023:e202307035. [PMID: 37293835 DOI: 10.1002/anie.202307035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Revised: 06/08/2023] [Accepted: 06/09/2023] [Indexed: 06/10/2023]
Abstract
π-Conjugated nanoribbons attract interest because of their unusual electronic structures and charge-transport behavior. Here, we report the synthesis of a series of fully edge-fused porphyrin-anthracene oligomeric ribbons (dimer and trimer), together with a computational study of the corresponding infinite polymer. The porphyrin dimer and trimer were synthesized in high yield, via oxidative cyclodehydrogenation of singly linked precursors, using 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) and trifluoromethanesulfonic acid (TfOH). The crystal structure of the dimer shows that the central π-system is flat, with a slight S-shaped wave distortion at each porphyrin terminal. The extended π-conjugation causes a dramatic red-shift in the absorption spectra: the absorption maxima of the fused dimer and trimer appear at 1188 nm and 1642 nm, respectively (for the nickel complexes dissolved in toluene). The coordinated metal in the dimer was changed from Ni to Mg, using p-tolylmagnesium bromide, providing access to free-base and Zn complexes. These results open a versatile avenue to longer π-conjugated nanoribbons with integrated metalloporphyrin units.
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Affiliation(s)
- He Zhu
- University of Oxford Department of Chemistry, Chemistry, UNITED KINGDOM
| | - Qiang Chen
- University of Oxford Department of Chemistry, Chemistry, UNITED KINGDOM
| | - Igor Rončević
- University of Oxford Department of Chemistry, Chemistry, UNITED KINGDOM
| | | | - Harry Laurence Anderson
- University of Oxford, Department of Chemistry, 12 Mansfield Road, Chemistry Research Laboratory, OX1 3TA, Oxford, UNITED KINGDOM
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15
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Saney L, Panduwawala T, Li X, Christensen KE, Genov M, Pretsch A, Pretsch D, Moloney MG. Synthesis of fused tetramate-oxazolidine and -imidazolidine derivatives and their antibacterial activity. Org Biomol Chem 2023. [PMID: 37232452 DOI: 10.1039/d3ob00594a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
A chemoselective route which provides direct access to bicyclic tetramates, making use of Dieckmann cyclisation of functionalised oxazolidines and imidazolidines derived from an aminomalonate, is reported; calculations suggest that the observed chemoselectivity is kinetically controlled and leads to the thermodynamically most stable product. Some compounds in the library showed modest antibacterial activity against Gram-positive bacteria, and this activity is maximal in a well-defined region of chemical space (554 < Mw < 722 g mol-1; 5.78 < cLogP < 7.16; 788 < MSA < 972 Å2; 10.3 < rel. PSA < 19.08).
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Affiliation(s)
- Liban Saney
- The Department of Chemistry, Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford, OX1 3TA, UK.
| | - Tharindi Panduwawala
- The Department of Chemistry, Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford, OX1 3TA, UK.
| | - Xiang Li
- The Department of Chemistry, Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford, OX1 3TA, UK.
- Department of Pharmaceutical Engineering, China Pharmaceutical University, Nanjing, 211198, P. R. China
| | - Kirsten E Christensen
- The Department of Chemistry, Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford, OX1 3TA, UK.
| | - Miroslav Genov
- Oxford Antibiotic Group, The Oxford Science Park, Magdalen Centre, Oxford OX4 4GA, UK
| | - Alexander Pretsch
- Oxford Antibiotic Group, The Oxford Science Park, Magdalen Centre, Oxford OX4 4GA, UK
| | - Dagmar Pretsch
- Oxford Antibiotic Group, The Oxford Science Park, Magdalen Centre, Oxford OX4 4GA, UK
| | - Mark G Moloney
- The Department of Chemistry, Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford, OX1 3TA, UK.
- Oxford Suzhou Centre for Advanced Research, Suzhou Industrial Park, Building A, 388 Ruo Shui Road, Jiangsu, 215123, P. R. China
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16
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Chen Q, Thompson AL, Christensen KE, Horton PN, Coles SJ, Anderson HL. β,β-Directly Linked Porphyrin Rings: Synthesis, Photophysical Properties, and Fullerene Binding. J Am Chem Soc 2023; 145:11859-11865. [PMID: 37201942 DOI: 10.1021/jacs.3c03549] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Cyclic porphyrin oligomers have been studied as models for photosynthetic light-harvesting antenna complexes and as potential receptors for supramolecular chemistry. Here, we report the synthesis of unprecedented β,β-directly linked cyclic zinc porphyrin oligomers, the trimer (CP3) and tetramer (CP4), by Yamamoto coupling of a 2,3-dibromoporphyrin precursor. Their three-dimensional structures were confirmed by nuclear magnetic resonance (NMR) spectroscopy, mass spectrometry, and single-crystal X-ray diffraction analyses. The minimum-energy geometries of CP3 and CP4 have propeller and saddle shapes, respectively, as calculated using density functional theory. Their different geometries result in distinct photophysical and electrochemical properties. The smaller dihedral angles between the porphyrin units in CP3, compared with CP4, result in stronger π-conjugation, splitting the ultraviolet-vis absorption bands and shifting them to longer wavelengths. Analysis of the crystallographic bond lengths indicates that the central benzene ring of the CP3 is partially aromatic [harmonic oscillator model of aromaticity (HOMA) 0.52], whereas the central cyclooctatetraene ring of the CP4 is non-aromatic (HOMA -0.02). The saddle-shaped structure of CP4 makes it a ditopic receptor for fullerenes, with affinity constants of (1.1 ± 0.4) × 105 M-1 for C70 and (2.2 ± 0.1) × 104 M-1 for C60, respectively, in toluene solution at 298 K. The formation of a 1:2 complex with C60 is confirmed by NMR titration and single-crystal X-ray diffraction.
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Affiliation(s)
- Qiang Chen
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Oxford OX1 3TA, U.K
| | - Amber L Thompson
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Oxford OX1 3TA, U.K
| | - Kirsten E Christensen
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Oxford OX1 3TA, U.K
| | - Peter N Horton
- National Crystallography Service, School of Chemistry, University of Southampton, Southampton SO17 1BJ, U.K
| | - Simon J Coles
- National Crystallography Service, School of Chemistry, University of Southampton, Southampton SO17 1BJ, U.K
| | - Harry L Anderson
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Oxford OX1 3TA, U.K
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17
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Formica M, Rogova T, Shi H, Sahara N, Ferko B, Farley AJM, Christensen KE, Duarte F, Yamazaki K, Dixon DJ. Catalytic enantioselective nucleophilic desymmetrization of phosphonate esters. Nat Chem 2023; 15:714-721. [PMID: 37127757 PMCID: PMC10159838 DOI: 10.1038/s41557-023-01165-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Accepted: 02/20/2023] [Indexed: 05/03/2023]
Abstract
Molecules that contain a stereogenic phosphorus atom are crucial to medicine, agrochemistry and catalysis. While methods are available for the selective construction of various chiral organophosphorus compounds, catalytic enantioselective approaches for their synthesis are far less common. Given the vastness of possible substituent combinations around a phosphorus atom, protocols for their preparation should also be divergent, providing facile access not only to one but to many classes of phosphorus compounds. Here we introduce a catalytic and enantioselective strategy for the preparation of an enantioenriched phosphorus(V) centre that can be diversified enantiospecifically to a wide range of biologically relevant phosphorus(V) compounds. The process, which involves an enantioselective nucleophilic substitution catalysed by a superbasic bifunctional iminophosphorane catalyst, can accommodate a wide range of carbon substituents at phosphorus. The resulting stable, yet versatile, synthetic intermediates can be combined with a multitude of medicinally relevant O-, N- and S-based nucleophiles.
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Affiliation(s)
- Michele Formica
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Oxford, UK
| | - Tatiana Rogova
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Oxford, UK
| | - Heyao Shi
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Oxford, UK
| | - Naoto Sahara
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Oxford, UK
- Graduate School of Engineering, Nagoya University, Nagoya, Japan
| | - Branislav Ferko
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Oxford, UK
| | - Alistair J M Farley
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Oxford, UK
| | - Kirsten E Christensen
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Oxford, UK
| | - Fernanda Duarte
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Oxford, UK
| | - Ken Yamazaki
- Division of Applied Chemistry, Okayama University, Okayama, Japan.
| | - Darren J Dixon
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Oxford, UK.
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18
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Saney L, Christensen KE, Genov M, Pretsch A, Pretsch D, Moloney MG. Tetramate derivatives by chemoselective Dieckmann ring closure of allo-phenylserines, and their antibacterial activity. Org Biomol Chem 2023; 21:4061-4071. [PMID: 37099402 DOI: 10.1039/d3ob00376k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/27/2023]
Abstract
A general route which provides direct access to substituted bicyclic tetramates, making use of Dieckmann cyclisation of oxazolidine derivatives derived from allo-phenylserines, is reported. Of interest is the high level of diastereoselectivity observed for the N-acylation reaction of oxazolidines and the complete chemoselectivity of their ring closure in the Dieckmann cyclisation. Significantly, the sense of the chemoselectivity is different to earlier reported threo-phenylserine systems, showing the importance of steric bulk around the bicyclic ring system. The derived C7-carboxamidotetramates, but not C7-acyl systems, exhibited potent antibacterial activity against MRSA, with the most active compounds exhibiting well-defined physicochemical and structure-activity properties. This work clearly demonstrates that densely functionalised tetramates are both readily available and may exhibit high levels of antibacterial activity.
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Affiliation(s)
- Liban Saney
- The Department of Chemistry, Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford, OX1 3TA, UK.
| | - Kirsten E Christensen
- The Department of Chemistry, Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford, OX1 3TA, UK.
| | - Miroslav Genov
- Oxford Antibiotic Group, The Oxford Science Park, Magdalen Centre, Oxford OX4 4GA, UK
| | - Alexander Pretsch
- Oxford Antibiotic Group, The Oxford Science Park, Magdalen Centre, Oxford OX4 4GA, UK
| | - Dagmar Pretsch
- Oxford Antibiotic Group, The Oxford Science Park, Magdalen Centre, Oxford OX4 4GA, UK
| | - Mark G Moloney
- The Department of Chemistry, Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford, OX1 3TA, UK.
- Oxford Suzhou Centre for Advanced Research, Building A, 388 Ruo Shui Road, Suzhou Industrial Park, Jiangsu, 215123, P.R. China
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19
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Horwitz MA, Dürr AB, Afratis K, Chen Z, Soika J, Christensen KE, Fushimi M, Paton RS, Gouverneur V. Regiodivergent Nucleophilic Fluorination under Hydrogen Bonding Catalysis: A Computational and Experimental Study. J Am Chem Soc 2023; 145:9708-9717. [PMID: 37079853 PMCID: PMC10161234 DOI: 10.1021/jacs.3c01303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/22/2023]
Abstract
The controlled programming of regiochemical outcomes in nucleophilic fluorination reactions with alkali metal fluoride is a problem yet to be solved. Herein, two synergistic approaches exploiting hydrogen bonding catalysis are presented. First, we demonstrate that modulating the charge density of fluoride with a hydrogen-bond donor urea catalyst directly influences the kinetic regioselectivity in the fluorination of dissymmetric aziridinium salts with aryl and ester substituents. Moreover, we report a urea-catalyzed formal dyotropic rearrangement, a thermodynamically controlled regiochemical editing process consisting of C-F bond scission followed by fluoride rebound. These findings offer a route to access enantioenriched fluoroamine regioisomers from a single chloroamine precursor, and more generally, new opportunities in regiodivergent asymmetric (bis)urea-based organocatalysis.
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Affiliation(s)
- Matthew A Horwitz
- Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, U.K
| | - Alexander B Dürr
- Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, U.K
| | - Konstantinos Afratis
- Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, U.K
| | - Zijun Chen
- Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, U.K
| | - Julia Soika
- Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, U.K
| | - Kirsten E Christensen
- Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, U.K
| | - Makoto Fushimi
- Takeda Pharmaceutical Company Limited, 26-1, Muraoka-Higashi 2-Chome, Fujisawa, Kanagawa 251-8555, Japan
| | - Robert S Paton
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80528, United States
| | - Véronique Gouverneur
- Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, U.K
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20
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Kučera R, Ellis SR, Yamazaki K, Hayward Cooke J, Chekshin N, Christensen KE, Hamlin TA, Dixon DJ. Enantioselective Total Synthesis of (-)-Himalensine A via a Palladium and 4-Hydroxyproline Co-catalyzed Desymmetrization of Vinyl-bromide-tethered Cyclohexanones. J Am Chem Soc 2023; 145:5422-5430. [PMID: 36820616 PMCID: PMC9999414 DOI: 10.1021/jacs.2c13710] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/24/2023]
Abstract
Herein, we describe the convergent enantioselective total synthesis of himalensine A in 18 steps, enabled by a highly enantio- and diastereoselective construction of the morphan core via a palladium/hydroxy proline co-catalyzed desymmetrization of vinyl-bromide-tethered cyclohexanones. The reaction pathway was illuminated by density functional theory calculations, which support an intramolecular Heck reaction of an in situ-generated enamine intermediate, where exquisite enantioselectivity arises from intramolecular carboxylate coordination to the vinyl palladium species in the rate- and enantio-determining carbopalladation steps. The reaction tolerates diverse N-derivatives, all-carbon quaternary centers, and trisubstituted olefins, providing access to molecular scaffolds found in a range of complex natural products. Following large-scale preparation of a key substrate and installation of a β-substituted enone moiety, the rapid construction of himalensine A was achieved using a highly convergent strategy based on an amide coupling/Michael addition/allylation/ring-closing metathesis sequence which allowed the introduction of three of the five rings in only three synthetic steps (after telescoping). Moreover, our strategy provides a new enantioselective access to a known tetracyclic late-stage intermediate that has been used previously in the synthesis of many Daphniphyllum alkaloids.
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Affiliation(s)
- Roman Kučera
- Department of Chemistry, Chemical Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, U.K
| | - Sam R Ellis
- Department of Chemistry, Chemical Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, U.K
| | - Ken Yamazaki
- Department of Chemistry, Chemical Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, U.K.,Department of Theoretical Chemistry, Amsterdam Institute of Molecular and Life Sciences (AIMMS), and Amsterdam Center for Multiscale Modeling (ACMM), Vrije Universiteit Amsterdam, De Boelelaan 1083, Amsterdam 1081 HV, The Netherlands
| | - Jack Hayward Cooke
- Department of Chemistry, Chemical Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, U.K
| | - Nikita Chekshin
- Department of Chemistry, Chemical Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, U.K
| | - Kirsten E Christensen
- Department of Chemistry, Chemical Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, U.K
| | - Trevor A Hamlin
- Department of Theoretical Chemistry, Amsterdam Institute of Molecular and Life Sciences (AIMMS), and Amsterdam Center for Multiscale Modeling (ACMM), Vrije Universiteit Amsterdam, De Boelelaan 1083, Amsterdam 1081 HV, The Netherlands
| | - Darren J Dixon
- Department of Chemistry, Chemical Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, U.K
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21
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Aynetdinova D, Jacques R, Christensen KE, Donohoe TJ. Alcohols as Efficient Intermolecular Initiators for a Highly Stereoselective Polyene Cyclisation Cascade. Chemistry 2023; 29:e202203732. [PMID: 36478469 PMCID: PMC10946764 DOI: 10.1002/chem.202203732] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 12/01/2022] [Accepted: 12/05/2022] [Indexed: 12/12/2022]
Abstract
The use of benzylic and allylic alcohols in HFIP solvent together with Ti(Oi Pr)4 has been shown to trigger a highly stereoselective polyene cyclisation cascade. Three new carbon-carbon bonds are made during the process and complete stereocontrol of up to five new stereogenic centers is observed. The reaction is efficient, has high functional group tolerance and is atom-economic generating water as a stoichiometric by-product. A new polyene substrate-class is employed, and subsequent mechanistic studies indicate a stereoconvergent mechanism. The products of this reaction can be used to synthesize steroid-analogues in a single step.
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Affiliation(s)
- Daniya Aynetdinova
- Department of ChemistryUniversity of OxfordChemistry Research LaboratoryOxfordOX1 3TAUK
| | - Reece Jacques
- Early Chemical Development, Medicinal Chemistry R&DVertex PharmaceuticalsAbingtonOX14 4RWUK
| | | | - Timothy J. Donohoe
- Department of ChemistryUniversity of OxfordChemistry Research LaboratoryOxfordOX1 3TAUK
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22
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Alexander C, Thom JA, Kenwright AM, Christensen KE, Sørensen TJ, Faulkner S. Chelating chloride using binuclear lanthanide complexes in water. Chem Sci 2023; 14:1194-1204. [PMID: 36756316 PMCID: PMC9891377 DOI: 10.1039/d2sc05417e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Accepted: 12/27/2022] [Indexed: 12/28/2022] Open
Abstract
Halide recognition by supramolecular receptors and coordination complexes in water is a long-standing challenge. In this work, we report chloride binding in water and in competing media by pre-organised binuclear kinetically inert lanthanide complexes, bridged by flexible -(CH2)2- and -(CH2)3- spacers, forming [Ln2(DO3A)2C-2] and [Ln2(DO3A)2C-3], respectively. These hydrophilic, neutral lanthanide coordination complexes are shown to bind chloride with apparent association constants of up to 105 M-1 in water and in buffered systems. Hydroxide bridging was observed in these complexes at basic pH, which was proven to be overcome by chloride. Thus, these lanthanide complexes show promise towards chloride recognition in biology and beyond. The results described here have clearly identified a new area of anion coordination chemistry that is ripe for detailed exploration.
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Affiliation(s)
- Carlson Alexander
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford 12 Mansfield Road Oxford OX1 3TA UK
| | - James A Thom
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford 12 Mansfield Road Oxford OX1 3TA UK
| | - Alan M Kenwright
- Department of Chemistry, University of Durham South Road Durham DH1 3LE UK
| | - Kirsten E Christensen
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford 12 Mansfield Road Oxford OX1 3TA UK
| | - Thomas Just Sørensen
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford 12 Mansfield Road Oxford OX1 3TA UK
- Nano-Science Centre and Department of Chemistry, University of Copenhagen 2100 København Ø Denmark
| | - Stephen Faulkner
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford 12 Mansfield Road Oxford OX1 3TA UK
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23
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Day A, Jenkins TC, Kischkewitz M, Christensen KE, Poole DL, Donohoe TJ. Metal and Activating Group Free C-4 Alkylation of Isoquinolines via a Temporary Dearomatization Strategy. Org Lett 2023; 25:614-618. [PMID: 36688518 PMCID: PMC9903316 DOI: 10.1021/acs.orglett.2c04149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
A simple method for the C-4 alkylation of isoquinolines is described using benzoic acid as a nucleophilic reagent and vinyl ketones as an electrophile. The reaction shows tolerance for substitution at C-3, and C-5-C-8 positions as well as allowing some variation of the vinyl ketone electrophiles. The products contain a carbonyl that can act as a synthetic handle for further manipulations giving esters, amines, or simple alkyl products.
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Affiliation(s)
- Aaron
J. Day
- Department
of Chemistry, University of Oxford, Chemistry Research Laboratory, Mansfield Road,
Oxford, OX1 3TA, United
Kingdom
| | - Timothy C. Jenkins
- Department
of Chemistry, University of Oxford, Chemistry Research Laboratory, Mansfield Road,
Oxford, OX1 3TA, United
Kingdom
| | - Marvin Kischkewitz
- Department
of Chemistry, University of Oxford, Chemistry Research Laboratory, Mansfield Road,
Oxford, OX1 3TA, United
Kingdom
| | - Kirsten E. Christensen
- Department
of Chemistry, University of Oxford, Chemistry Research Laboratory, Mansfield Road,
Oxford, OX1 3TA, United
Kingdom
| | - Darren L. Poole
- Discovery
High-Throughput Chemistry, Medicinal Chemistry, GlaxoSmithKline Medicines Research Centre, Gunnels Wood Road, Stevenage, Hertfordshire SG1 2NY, United Kingdom
| | - Timothy J. Donohoe
- Department
of Chemistry, University of Oxford, Chemistry Research Laboratory, Mansfield Road,
Oxford, OX1 3TA, United
Kingdom,E-mail:
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24
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Andrews KG, Christensen KE. Access to Amide-Linked Organic Cages by in situ Trapping of Metastable Imine Assemblies: Solution Phase Bisamine Recognition. Chemistry 2023; 29:e202300063. [PMID: 36638051 DOI: 10.1002/chem.202300063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Revised: 01/12/2023] [Accepted: 01/12/2023] [Indexed: 01/14/2023]
Abstract
Molecular cages are sought after as receptors and catalysts. However, typical dynamic covalent chemistry approaches restrict the shape-persistence, solubility and stability of self-assembled organic cages. As a result, organic cages occupy a narrow chemical and functional space, and solution-phase applications and studies remain rare. We report an in situ trapping protocol, using Pinnick oxidation conditions, to convert soluble metastable imine assemblies to robust amide cages, and exemplify the method to access previously inaccessible organic cages. The new cages are internally functionalised with two constrained and diametrically opposed carboxylic acid groups that can distinguish between functionalised piperazines in THF. We anticipate our approach will broaden access to robust, soluble, self-assembled organic cages of an unsymmetrical or semi-flexible nature, which in turn will drive advances in solution-phase applications of molecular cages.
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Affiliation(s)
- Keith G Andrews
- Department of Chemistry, University of Oxford, 12 Mansfield Rd, Oxford, OX1 3TA, UK
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25
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Hicks H, Brown DS, Sam Chan HS, Sousa BA, Christensen KE, Burton JW. Total Synthesis and Structure Confirmation of ( E) and ( Z)-Ocellenyne. Org Lett 2022; 24:9174-9178. [PMID: 36508492 PMCID: PMC9791679 DOI: 10.1021/acs.orglett.2c03524] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The (E/Z)-ocellenynes are C15 dibrominated Laurencia natural products whose structures have been subject to several reassignments on the basis of extensive NMR analysis, biosynthetic postulates, and DFT calculations. Herein, we report the synthesis of both (E)- and (Z)-ocellenyne, which, in combination with single crystal X-ray diffraction studies, allows their absolute configuration to be established and defines the configuration of the syn-12,13-dibromide as being (S, S) in keeping with their proposed biogenesis from the (6S, 7S)-laurediols.
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Affiliation(s)
- Harry
B. Hicks
- Chemistry
Research Laboratory, University of Oxford, Mansfield Road, Oxford, OX1 3TA, U.K.
| | - Daniel S. Brown
- Chemistry
Research Laboratory, University of Oxford, Mansfield Road, Oxford, OX1 3TA, U.K.
| | - Hau Sun Sam Chan
- Chemistry
Research Laboratory, University of Oxford, Mansfield Road, Oxford, OX1 3TA, U.K.
| | - Bruno A. Sousa
- Vertex
Pharmaceuticals, 86-88
Jubilee Avenue, Milton Park, Abingdon, OX14 4RW, U.K.
| | - Kirsten E. Christensen
- Chemistry
Research Laboratory, University of Oxford, Mansfield Road, Oxford, OX1 3TA, U.K.
| | - Jonathan W. Burton
- Chemistry
Research Laboratory, University of Oxford, Mansfield Road, Oxford, OX1 3TA, U.K.,
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26
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Dohle W, Asiki H, Gruchot W, Foster PA, Sahota HK, Bai R, Christensen KE, Hamel E, Potter BVL. 2-Difluoromethoxy-Substituted Estratriene Sulfamates: Synthesis, Antiproliferative SAR, Antitubulin Activity, and Steroid Sulfatase Inhibition. ChemMedChem 2022; 17:e202200408. [PMID: 36109340 PMCID: PMC9742152 DOI: 10.1002/cmdc.202200408] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2022] [Revised: 09/14/2022] [Indexed: 01/14/2023]
Abstract
2-Difluoromethoxyestratriene derivatives were designed to improve potency and in vivo stability of the drug candidate 2-methoxyestradiol (2ME2). Compound evaluation in vitro against the proliferation of MCF-7 and MDA MB-231 breast cancer cells, as inhibitors of tubulin polymerisation and also steroid sulfatase (STS) both in cell lysates and in whole cells, showed promising activities. In antiproliferative assays 2-difluoromethoxyestradiol was less potent than 2ME2, but its sulfamates were often more potent than their corresponding non-fluorinated analogues. The fluorinated bis-sulfamate is a promising antiproliferative agent in MCF-7 cells (GI50 0.28 μM) vs the known 2-methoxyestradiol-3,17-O,O-bissulfamate (STX140, GI50 0.52 μM), confirming the utility of our approach. Compounds were also evaluated in the NCI 60-cell line panel and the fluorinated bis-sulfamate derivative displayed very good overall activities with a sub-micromolar average GI50 . It was a very potent STS inhibitor in whole JEG-3 cells (IC50 3.7 nM) similar to STX140 (4.2 nM) and additionally interferes with tubulin assembly in vitro and colchicine binding to tubulin. An X-ray study of 2-difluoromethoxy-3-benzyloxyestra-1,3,5(10)-trien-17-one examined conformational aspects of the fluorinated substituent. The known related derivative 2-difluoromethyl-3-sulfamoyloxyestrone was evaluated for STS inhibition in whole JEG-3 cells and showed an excellent IC50 of 55 pM.
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Affiliation(s)
- Wolfgang Dohle
- Medicinal Chemistry & Drug Discovery, Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, OX1 3QT, UK
| | - Hannah Asiki
- Medicinal Chemistry & Drug Discovery, Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, OX1 3QT, UK
| | - Wojciech Gruchot
- Medicinal Chemistry & Drug Discovery, Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, OX1 3QT, UK
| | - Paul A Foster
- Institute of Metabolism & Systems Research, University of Birmingham, 2nd Floor IBR Tower Edgbaston, Birmingham, B15 2TT, UK
- Centre for Endocrinology, Metabolism and Diabetes, University of Birmingham, Birmingham Health Partners, Birmingham, B15 2TT, UK
| | - Havreen K Sahota
- Institute of Metabolism & Systems Research, University of Birmingham, 2nd Floor IBR Tower Edgbaston, Birmingham, B15 2TT, UK
| | - Ruoli Bai
- Molecular Pharmacology Branch, Developmental Therapeutics Program, Division of Cancer Treatment and Diagnosis, National Cancer Institute, Frederick, MD, 21702, USA
| | - Kirsten E Christensen
- Chemical Crystallography, Department of Chemistry, University of Oxford, Mansfield Road, Oxford, OX1 3TA, UK
| | - Ernest Hamel
- Molecular Pharmacology Branch, Developmental Therapeutics Program, Division of Cancer Treatment and Diagnosis, National Cancer Institute, Frederick, MD, 21702, USA
| | - Barry V L Potter
- Medicinal Chemistry & Drug Discovery, Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, OX1 3QT, UK
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27
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Dohle W, Asiki H, Gruchot W, Foster PA, Sahota HK, Bai R, Christensen KE, Hamel E, Potter BVL. Front Cover: 2‐Difluoromethoxy‐Substituted Estratriene Sulfamates: Synthesis, Antiproliferative SAR, Antitubulin Activity, and Steroid Sulfatase Inhibition (ChemMedChem 23/2022). ChemMedChem 2022. [DOI: 10.1002/cmdc.202200639] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Wolfgang Dohle
- Medicinal Chemistry & Drug Discovery Department of Pharmacology University of Oxford Mansfield Road Oxford OX1 3QT UK
| | - Hannah Asiki
- Medicinal Chemistry & Drug Discovery Department of Pharmacology University of Oxford Mansfield Road Oxford OX1 3QT UK
| | - Wojciech Gruchot
- Medicinal Chemistry & Drug Discovery Department of Pharmacology University of Oxford Mansfield Road Oxford OX1 3QT UK
| | - Paul A. Foster
- Institute of Metabolism & Systems Research University of Birmingham 2nd Floor IBR Tower Edgbaston Birmingham B15 2TT UK
- Centre for Endocrinology Metabolism and Diabetes University of Birmingham Birmingham Health Partners Birmingham B15 2TT UK
| | - Havreen K. Sahota
- Institute of Metabolism & Systems Research University of Birmingham 2nd Floor IBR Tower Edgbaston Birmingham B15 2TT UK
| | - Ruoli Bai
- Molecular Pharmacology Branch Developmental Therapeutics Program Division of Cancer Treatment and Diagnosis National Cancer Institute Frederick MD 21702 USA
| | - Kirsten E. Christensen
- Chemical Crystallography Department of Chemistry University of Oxford Mansfield Road Oxford OX1 3TA UK
| | - Ernest Hamel
- Molecular Pharmacology Branch Developmental Therapeutics Program Division of Cancer Treatment and Diagnosis National Cancer Institute Frederick MD 21702 USA
| | - Barry V. L. Potter
- Medicinal Chemistry & Drug Discovery Department of Pharmacology University of Oxford Mansfield Road Oxford OX1 3QT UK
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28
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Hoff O, Kratena N, Aynetdinova D, Christensen KE, Donohoe TJ. A Vicinal Diol Approach for the Total Synthesis of Molestin E, ent-Sinulacembranolide A and ent-Sinumaximol A. Chemistry 2022; 28:e202202464. [PMID: 35946550 PMCID: PMC9826425 DOI: 10.1002/chem.202202464] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Indexed: 01/11/2023]
Abstract
In this work an approach for the synthesis of furanocembranoid natural products containing the C-7,8-diol moiety is disclosed. This culminated in the first total synthesis of the natural product molestin E, together with ent-sinulacembranolide A and ent-sinumaximol A as well as a thorough exploration of their chemistry. Late-stage ring-closure of the C-7,8-diols to the corresponding epoxides was also demonstrated. Key features of this synthetic strategy include a stereoselective Baylis-Hillman reaction, ring-closing metathesis and Shiina macrolactonisation. Chiral-pool materials were deployed to ensure the desired absolute stereochemistry which was confirmed by late-stage single crystal X-ray diffraction.
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Affiliation(s)
- Oskar Hoff
- Department of ChemistryUniversity of OxfordChemistry Research LaboratoryMansfield RoadOxfordOX1 3TAUK
| | - Nicolas Kratena
- Department of ChemistryUniversity of OxfordChemistry Research LaboratoryMansfield RoadOxfordOX1 3TAUK
| | - Daniya Aynetdinova
- Department of ChemistryUniversity of OxfordChemistry Research LaboratoryMansfield RoadOxfordOX1 3TAUK
| | - Kirsten E. Christensen
- Department of ChemistryUniversity of OxfordChemistry Research LaboratoryMansfield RoadOxfordOX1 3TAUK
| | - Timothy J. Donohoe
- Department of ChemistryUniversity of OxfordChemistry Research LaboratoryMansfield RoadOxfordOX1 3TAUK
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29
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Kerckhoffs A, Christensen KE, Langton MJ. Fast relaxing red and near-IR switchable azobenzenes with chalcogen and halogen substituents: periodic trends, tuneable thermal half-lives and chalcogen bonding. Chem Sci 2022; 13:11551-11559. [PMID: 36320400 PMCID: PMC9555560 DOI: 10.1039/d2sc04601f] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Accepted: 09/18/2022] [Indexed: 11/08/2023] Open
Abstract
Molecular photoswitches operating in the red to near-IR region with controllable thermal relaxation rates are attractive components for photo-regulating biological processes. Herein, we report the synthesis of red-shifted azobenzenes functionalised with the heavier chalcogens and halogens that meet these requirements for biological application; namely fatigue-resistant photo-switching with red and near IR light and functional handles for further functionalisation for application. We report robust periodic trends for the chalcogen and halogen azobenzene series, and exploit intramolecular chalcogen bonding to tune and redshift the absorption maxima, supported by photo-physical measurements and solid-state structural analysis. Remarkably, the rate of the Z → E thermal isomerisation can be tuned over timescales spanning 107 s by judicious choice of chalcogen and halogen substituents.
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Affiliation(s)
- Aidan Kerckhoffs
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford 12 Mansfield Road Oxford OX1 3TA UK
| | - Kirsten E Christensen
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford 12 Mansfield Road Oxford OX1 3TA UK
| | - Matthew J Langton
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford 12 Mansfield Road Oxford OX1 3TA UK
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30
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Saney L, Christensen KE, Li X, Genov M, Pretsch A, Pretsch D, Moloney MG. Tetramate Derivatives by Chemoselective Dieckmann Ring Closure of threo-Phenylserines and Their Antibacterial Activity. J Org Chem 2022; 87:12240-12249. [PMID: 36052923 PMCID: PMC9486951 DOI: 10.1021/acs.joc.2c01382] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
![]()
A general route, which provides direct access to substituted
bicyclic
tetramates, making use of Dieckmann cyclization of oxazolidines derived
from threo-arylserines, is reported; the latter were
found to be available by an efficient aldol-like reaction of glycine
with some substituted benzaldehydes under alkaline conditions. The
tetramates were found to release chelated metal cations acquired during
chromatographic purification by mild acid wash. Some compounds in
the library showed good antibacterial activity against Gram-positive
bacteria. Cheminformatic analysis demonstrates that the most active
compounds were Ro5-compliant and occupy a narrow region of chemical
space, distinct from that occupied by other known antibiotics, with
the most potent compounds having 399 < Mw < 530 Da;
3.5 < cLogP < 6.6; 594 < MSA <818 Å2; 9.6 < rel. PSA <13.3%. MIC values were shifted to
higher concentrations when tested in the presence of HSA or blood,
but was not completely abolished, consistent with a plasma protein
binding (PPB) effect.
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Affiliation(s)
- Liban Saney
- The Department of Chemistry, Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, U.K
| | - Kirsten E Christensen
- The Department of Chemistry, Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, U.K
| | - Xiang Li
- The Department of Chemistry, Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, U.K.,Department of Pharmaceutical Engineering, China Pharmaceutical University, Nanjing 211198, P. R. China
| | - Miroslav Genov
- Oxford Antibiotic Group, The Oxford Science Park, Magdalen Centre, Oxford OX4 4GA, U.K
| | - Alexander Pretsch
- Oxford Antibiotic Group, The Oxford Science Park, Magdalen Centre, Oxford OX4 4GA, U.K
| | - Dagmar Pretsch
- Oxford Antibiotic Group, The Oxford Science Park, Magdalen Centre, Oxford OX4 4GA, U.K
| | - Mark G Moloney
- The Department of Chemistry, Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, U.K.,Oxford Suzhou Centre for Advanced Research, Suzhou Industrial Park, Building A, 388 Ruo Shui Road, Jiangsu 215123, P.R. China
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31
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Cox L, Zhu Y, Smith PJ, Christensen KE, Sidera Portela M, Donohoe TJ. Alcohols as Alkylating Agents in the Cation‐Induced Formation of Nitrogen Heterocycles. Angew Chem Int Ed Engl 2022; 61:e202206800. [PMID: 35770710 PMCID: PMC9546487 DOI: 10.1002/anie.202206800] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Indexed: 11/06/2022]
Affiliation(s)
- Lydia Cox
- Department of Chemistry University of Oxford Chemistry Research Laboratory Mansfield Road Oxford OX1 3TA UK
| | - Yuxiang Zhu
- Department of Chemistry University of Oxford Chemistry Research Laboratory Mansfield Road Oxford OX1 3TA UK
| | - Philip J. Smith
- Department of Chemistry University of Oxford Chemistry Research Laboratory Mansfield Road Oxford OX1 3TA UK
| | - Kirsten E. Christensen
- Department of Chemistry University of Oxford Chemistry Research Laboratory Mansfield Road Oxford OX1 3TA UK
| | | | - Timothy J. Donohoe
- Department of Chemistry University of Oxford Chemistry Research Laboratory Mansfield Road Oxford OX1 3TA UK
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32
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Zhang Y, Goetzke FW, Christensen KE, Fletcher SP. Asymmetric Synthesis of Nortropanes via Rh-Catalyzed Allylic Arylation. ACS Catal 2022; 12:8995-9002. [PMID: 35966601 PMCID: PMC9361292 DOI: 10.1021/acscatal.2c02259] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Revised: 06/27/2022] [Indexed: 12/05/2022]
Abstract
![]()
Tropane derivatives are extensively used in medicine,
but catalytic
asymmetric methods for their synthesis are underexplored. Here, we
report Rh-catalyzed asymmetric Suzuki–Miyaura-type cross-coupling
reactions between a racemic N-Boc-nortropane-derived
allylic chloride and (hetero)aryl boronic esters. The reaction proceeds via an unexpected kinetic resolution, and the resolved enantiopure
allyl chloride can undergo highly enantiospecific reactions with N-,
O-, and S-containing nucleophiles. The method was applied in a highly
stereoselective formal synthesis of YZJ-1139(1), a potential insomnia
treatment that recently completed Phase II clinical trials. Our report
represents an asymmetric catalytic method for the synthesis of YZJ-1139(1)
and related compounds.
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Affiliation(s)
- Yan Zhang
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, United Kingdom
| | - F. Wieland Goetzke
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, United Kingdom
| | - Kirsten E. Christensen
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, United Kingdom
| | - Stephen P. Fletcher
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, United Kingdom
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33
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Kischkewitz M, Marinic B, Kratena N, Lai Y, Hepburn HB, Dow M, Christensen KE, Donohoe TJ. Evolution of the Dearomative Functionalization of Activated Quinolines and Isoquinolines: Expansion of the Electrophile Scope. Angew Chem Int Ed Engl 2022; 61:e202204682. [PMID: 35560761 PMCID: PMC9321684 DOI: 10.1002/anie.202204682] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Indexed: 11/09/2022]
Abstract
Herein we disclose a mild protocol for the reductive functionalisation of quinolinium and isoquinolinium salts. The reaction proceeds under transition-metal-free conditions as well as under rhodium catalysis with very low catalyst loadings (0.01 mol %) and uses inexpensive formic acid as the terminal reductant. A wide range of electrophiles, including enones, imides, unsaturated esters and sulfones, β-nitro styrenes and aldehydes are intercepted by the in situ formed enamine species forming a large variety of substituted tetrahydro(iso)quinolines. Electrophiles are incorporated at the C-3 and C-4 position for quinolines and isoquinolines respectively, providing access to substitution patterns which are not favoured in electrophilic or nucleophilic aromatic substitution. Finally, this reactivity was exploited to facilitate three types of annulation reactions, giving rise to complex polycyclic products of a formal [3+3] or [4+2] cycloaddition.
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Affiliation(s)
- Marvin Kischkewitz
- Department of ChemistryUniversity of OxfordChemistry Research LaboratoryMansfield RoadOxfordOX1 3TAUK
| | - Bruno Marinic
- Department of ChemistryUniversity of OxfordChemistry Research LaboratoryMansfield RoadOxfordOX1 3TAUK
| | - Nicolas Kratena
- Department of ChemistryUniversity of OxfordChemistry Research LaboratoryMansfield RoadOxfordOX1 3TAUK
| | - Yonglin Lai
- Department of ChemistryUniversity of OxfordChemistry Research LaboratoryMansfield RoadOxfordOX1 3TAUK
| | - Hamish B. Hepburn
- Department of ChemistryUniversity of OxfordChemistry Research LaboratoryMansfield RoadOxfordOX1 3TAUK
| | - Mark Dow
- Chemical Development, Pharmaceutical Technology & DevelopmentOperations, AstraZenecaMacclesfieldSK10 2NAUK
| | - Kirsten E. Christensen
- Department of ChemistryUniversity of OxfordChemistry Research LaboratoryMansfield RoadOxfordOX1 3TAUK
| | - Timothy J. Donohoe
- Department of ChemistryUniversity of OxfordChemistry Research LaboratoryMansfield RoadOxfordOX1 3TAUK
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34
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Kischkewitz M, Marinic B, Kratena N, Lai Y, Hepburn HB, Dow M, Christensen KE, Donohoe TJ. Evolution of the Dearomative Functionalization of Activated Quinolines and Isoquinolines: Expansion of the Electrophile Scope. Angew Chem Weinheim Bergstr Ger 2022; 134:e202204682. [PMID: 38505668 PMCID: PMC10946825 DOI: 10.1002/ange.202204682] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Indexed: 11/07/2022]
Abstract
Herein we disclose a mild protocol for the reductive functionalisation of quinolinium and isoquinolinium salts. The reaction proceeds under transition-metal-free conditions as well as under rhodium catalysis with very low catalyst loadings (0.01 mol %) and uses inexpensive formic acid as the terminal reductant. A wide range of electrophiles, including enones, imides, unsaturated esters and sulfones, β-nitro styrenes and aldehydes are intercepted by the in situ formed enamine species forming a large variety of substituted tetrahydro(iso)quinolines. Electrophiles are incorporated at the C-3 and C-4 position for quinolines and isoquinolines respectively, providing access to substitution patterns which are not favoured in electrophilic or nucleophilic aromatic substitution. Finally, this reactivity was exploited to facilitate three types of annulation reactions, giving rise to complex polycyclic products of a formal [3+3] or [4+2] cycloaddition.
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Affiliation(s)
- Marvin Kischkewitz
- Department of ChemistryUniversity of OxfordChemistry Research LaboratoryMansfield RoadOxfordOX1 3TAUK
| | - Bruno Marinic
- Department of ChemistryUniversity of OxfordChemistry Research LaboratoryMansfield RoadOxfordOX1 3TAUK
| | - Nicolas Kratena
- Department of ChemistryUniversity of OxfordChemistry Research LaboratoryMansfield RoadOxfordOX1 3TAUK
| | - Yonglin Lai
- Department of ChemistryUniversity of OxfordChemistry Research LaboratoryMansfield RoadOxfordOX1 3TAUK
| | - Hamish B. Hepburn
- Department of ChemistryUniversity of OxfordChemistry Research LaboratoryMansfield RoadOxfordOX1 3TAUK
| | - Mark Dow
- Chemical Development, Pharmaceutical Technology & DevelopmentOperations, AstraZenecaMacclesfieldSK10 2NAUK
| | - Kirsten E. Christensen
- Department of ChemistryUniversity of OxfordChemistry Research LaboratoryMansfield RoadOxfordOX1 3TAUK
| | - Timothy J. Donohoe
- Department of ChemistryUniversity of OxfordChemistry Research LaboratoryMansfield RoadOxfordOX1 3TAUK
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35
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Hall CJJ, Marriott IS, Christensen KE, Day AJ, Goundry WRF, Donohoe TJ. Extension of hydrogen borrowing alkylation reactions for the total synthesis of (-)-γ-lycorane. Chem Commun (Camb) 2022; 58:4966-4968. [PMID: 35348143 DOI: 10.1039/d2cc01248k] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The total synthesis of (-)-γ-lycorane (10 steps) and synthesis of (±)-γ-lycorane (8 steps) was completed from cyclohexenone. A new two step hydrogen borrowing alkylation of an aziridinyl alcohol, coupled with a Ph* (Me5C6) deprotection/cyclisation procedure was developed for de novo formation of the fused 6,5 heterocyclic ring. This work is one of the first examples of hydrogen borrowing C-C bond formation being used as a key step in a total synthesis project.
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Affiliation(s)
- Christopher J J Hall
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory, Mansfield Road, Oxford, OX1 3TA, UK.
| | - Indi S Marriott
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory, Mansfield Road, Oxford, OX1 3TA, UK.
| | - Kirsten E Christensen
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory, Mansfield Road, Oxford, OX1 3TA, UK.
| | - Aaron J Day
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory, Mansfield Road, Oxford, OX1 3TA, UK.
| | - William R F Goundry
- Early Chemical Development, Pharmaceutical Sciences, R&D, AstraZeneca, Macclesfield, UK
| | - Timothy J Donohoe
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory, Mansfield Road, Oxford, OX1 3TA, UK.
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36
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Wang J, Horwitz MA, Dürr AB, Ibba F, Pupo G, Gao Y, Ricci P, Christensen KE, Pathak TP, Claridge TDW, Lloyd-Jones GC, Paton RS, Gouverneur V. Asymmetric Azidation under Hydrogen Bonding Phase-Transfer Catalysis: A Combined Experimental and Computational Study. J Am Chem Soc 2022; 144:4572-4584. [PMID: 35230845 PMCID: PMC8931729 DOI: 10.1021/jacs.1c13434] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
![]()
Asymmetric catalytic
azidation has increased in importance to access
enantioenriched nitrogen containing molecules, but methods that employ
inexpensive sodium azide remain scarce. This encouraged us to undertake
a detailed study on the application of hydrogen bonding phase-transfer
catalysis (HB-PTC) to enantioselective azidation with sodium azide.
So far, this phase-transfer manifold has been applied exclusively
to insoluble metal alkali fluorides for carbon–fluorine bond
formation. Herein, we disclose the asymmetric ring opening of meso aziridinium electrophiles derived from β-chloroamines
with sodium azide in the presence of a chiral bisurea catalyst. The
structure of novel hydrogen bonded azide complexes was analyzed computationally,
in the solid state by X-ray diffraction, and in solution phase by 1H and 14N/15N NMR spectroscopy. With N-isopropylated BINAM-derived bisurea, end-on binding of
azide in a tripodal fashion to all three NH bonds is energetically
favorable, an arrangement reminiscent of the corresponding dynamically
more rigid trifurcated hydrogen-bonded fluoride complex. Computational
analysis informs that the most stable transition state leading to
the major enantiomer displays attack from the hydrogen-bonded end
of the azide anion. All three H-bonds are retained in the transition
state; however, as seen in asymmetric HB-PTC fluorination, the H-bond
between the nucleophile and the monodentate urea lengthens most noticeably
along the reaction coordinate. Kinetic studies corroborate with the
turnover rate limiting event resulting in a chiral ion pair containing
an aziridinium cation and a catalyst-bound azide anion, along with
catalyst inhibition incurred by accumulation of NaCl. This study demonstrates
that HB-PTC can serve as an activation mode for inorganic salts other
than metal alkali fluorides for applications in asymmetric synthesis.
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Affiliation(s)
- Jimmy Wang
- Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, U.K
| | - Matthew A Horwitz
- Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, U.K
| | - Alexander B Dürr
- Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, U.K
| | - Francesco Ibba
- Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, U.K
| | - Gabriele Pupo
- Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, U.K
| | - Yuan Gao
- School of Chemistry, University of Edinburgh, Edinburgh EH9 3FJ, U.K
| | - Paolo Ricci
- Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, U.K
| | - Kirsten E Christensen
- Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, U.K
| | - Tejas P Pathak
- Novartis Institutes for Biomedical Research, 22 Windsor Street, Cambridge, Massachusetts 02139, United States
| | - Timothy D W Claridge
- Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, U.K
| | - Guy C Lloyd-Jones
- School of Chemistry, University of Edinburgh, Edinburgh EH9 3FJ, U.K
| | - Robert S Paton
- Department of Chemistry, Colorado State University, Fort Collins, Colorado 80528, United States
| | - Véronique Gouverneur
- Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, U.K
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37
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Moloney MG, Ibbotson LT, Christensen KE, Genov M, Pretsch A, Pretsch D. Skeletal Analogues of UCS1025A and B by Cyclization of Maleimides: Synthesis and Biological Activity. Synlett 2022. [DOI: 10.1055/s-0040-1719876] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
AbstractApplication of a direct ring-closing approach which exploits an intramolecular aldol reaction with a ketene silyl acetal onto a remote imide function leading to the core skeleton of UCS1025A and B effectively provides access to small library of substituted analogues; of interest is their complete lack of antibacterial activity against MRSA (Gram+) and E. coli (Gram–) bacterial strains.
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Affiliation(s)
- Mark G. Moloney
- The Department of Chemistry, Chemistry Research Laboratory, University of Oxford
- Oxford Suzhou Centre for Advanced Research
| | - Lewis T. Ibbotson
- The Department of Chemistry, Chemistry Research Laboratory, University of Oxford
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38
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Xu W, Leary E, Sangtarash S, Jirasek M, González MT, Christensen KE, Abellán Vicente L, Agraït N, Higgins SJ, Nichols RJ, Lambert CJ, Anderson HL. A Peierls Transition in Long Polymethine Molecular Wires: Evolution of Molecular Geometry and Single-Molecule Conductance. J Am Chem Soc 2021; 143:20472-20481. [PMID: 34817985 DOI: 10.1021/jacs.1c10747] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Molecules capable of mediating charge transport over several nanometers with minimal decay in conductance have fundamental and technological implications. Polymethine cyanine dyes are fascinating molecular wires because up to a critical length, they have no bond-length alternation (BLA) and their electronic structure resembles a one-dimensional free-electron gas. Beyond this threshold, they undergo a symmetry-breaking Peierls transition, which increases the HOMO-LUMO gap. We have investigated cationic cyanines with central polymethine chains of 5-13 carbon atoms (Cy3+-Cy11+). The absorption spectra and crystal structures show that symmetry breaking is sensitive to the polarity of the medium and the size of the counterion. X-ray crystallography reveals that Cy9·PF6 and Cy11·B(C6F5)4 are Peierls distorted, with high BLA at one end of the π-system, away from the partially delocalized positive charge. This pattern of BLA distribution resembles that of solitons in polyacetylene. The single-molecule conductance is essentially independent of molecular length for the polymethine salts of Cy3+-Cy11+ with the large B(C6F5)4- counterion, but with the PF6- counterion, the conductance decreases for the longer molecules, Cy7+-Cy11+, because this smaller anion polarizes the π-system, inducing a symmetry-breaking transition. At higher bias (0.9 V), the conductance of the shorter chains, Cy3+-Cy7+, increases with length (negative attenuation factor, β = -1.6 nm-1), but the conductance still drops in Cy9+ and Cy11+ with the small polarizing PF6- counteranion.
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Affiliation(s)
- Wenjun Xu
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Oxford OX1 3TA, United Kingdom
| | - Edmund Leary
- Fundación IMDEA Nanociencia, Calle Faraday 9, Campus Universitario de Cantoblanco, 28049 Madrid, Spain
| | - Sara Sangtarash
- School of Engineering, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - Michael Jirasek
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Oxford OX1 3TA, United Kingdom
| | - M Teresa González
- Fundación IMDEA Nanociencia, Calle Faraday 9, Campus Universitario de Cantoblanco, 28049 Madrid, Spain
| | - Kirsten E Christensen
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Oxford OX1 3TA, United Kingdom
| | - Lydia Abellán Vicente
- Fundación IMDEA Nanociencia, Calle Faraday 9, Campus Universitario de Cantoblanco, 28049 Madrid, Spain
| | - Nicolás Agraït
- Fundación IMDEA Nanociencia, Calle Faraday 9, Campus Universitario de Cantoblanco, 28049 Madrid, Spain.,Departamento de Física de la Materia Condensada, IFIMAC and Instituto "Nicolás Cabrera", Universidad Autónoma de Madrid, 28049 Madrid, Spain
| | - Simon J Higgins
- Department of Chemistry, Donnan and Robert Robinson Laboratories, University of Liverpool, Liverpool L69 7ZD, United Kingdom
| | - Richard J Nichols
- Department of Chemistry, Donnan and Robert Robinson Laboratories, University of Liverpool, Liverpool L69 7ZD, United Kingdom
| | - Colin J Lambert
- Department of Physics, Lancaster University, Lancaster LA1 4YW, United Kingdom
| | - Harry L Anderson
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Oxford OX1 3TA, United Kingdom
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39
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Moloney MG, O’Shaughnessy L, Hutchinson C, Waldron A, Christensen KE. Pyrroloimidazolediones Derived from Aminomalonates and Benzaldehydes. Synlett 2021. [DOI: 10.1055/s-0040-1720888] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
AbstractBicyclic lactams can be prepared from diethyl aminomalonate and substituted benzaldehydes by formation of a dimerised imidazolidine cycloadduct followed by a Dieckmann ring closure. The resulting N,N-heterocycles are metal-chelating but show no antibacterial activity.
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Affiliation(s)
- Mark G. Moloney
- The Department of Chemistry, Chemistry Research Laboratory, University of Oxford
- Oxford Suzhou Centre for Advanced Research
| | - Lewis O’Shaughnessy
- The Department of Chemistry, Chemistry Research Laboratory, University of Oxford
| | - Charles Hutchinson
- The Department of Chemistry, Chemistry Research Laboratory, University of Oxford
| | - Adam Waldron
- The Department of Chemistry, Chemistry Research Laboratory, University of Oxford
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40
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Maitland JAP, Leitch JA, Yamazaki K, Christensen KE, Cassar DJ, Hamlin TA, Dixon DJ. Switchable, Reagent‐Controlled Diastereodivergent Photocatalytic Carbocyclisation of Imine‐Derived α‐Amino Radicals. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202107253] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- J. Andrew P. Maitland
- Department of Chemistry Chemistry Research Laboratory University of Oxford 12 Mansfield Road Oxford OX1 3TA UK
| | - Jamie A. Leitch
- Department of Chemistry Chemistry Research Laboratory University of Oxford 12 Mansfield Road Oxford OX1 3TA UK
- Current address: Department of Pharmaceutical and Biological Chemistry UCL (University College London) School of Pharmacy 29–39 Brunswick Square London WC1N 1AX UK
| | - Ken Yamazaki
- Department of Chemistry Chemistry Research Laboratory University of Oxford 12 Mansfield Road Oxford OX1 3TA UK
- Department of Theoretical Chemistry Amsterdam Institute of Molecular and Life Sciences (AIMMS) Amsterdam Center for Multiscale Modeling (ACMM) Vrije Universiteit Amsterdam De Boelelaan 1083 1081 HV Amsterdam The Netherlands
| | - Kirsten E. Christensen
- Department of Chemistry Chemistry Research Laboratory University of Oxford 12 Mansfield Road Oxford OX1 3TA UK
| | | | - Trevor A. Hamlin
- Department of Theoretical Chemistry Amsterdam Institute of Molecular and Life Sciences (AIMMS) Amsterdam Center for Multiscale Modeling (ACMM) Vrije Universiteit Amsterdam De Boelelaan 1083 1081 HV Amsterdam The Netherlands
| | - Darren J. Dixon
- Department of Chemistry Chemistry Research Laboratory University of Oxford 12 Mansfield Road Oxford OX1 3TA UK
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41
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Maitland JAP, Leitch JA, Yamazaki K, Christensen KE, Cassar DJ, Hamlin TA, Dixon DJ. Switchable, Reagent-Controlled Diastereodivergent Photocatalytic Carbocyclisation of Imine-Derived α-Amino Radicals. Angew Chem Int Ed Engl 2021; 60:24116-24123. [PMID: 34449968 PMCID: PMC8597041 DOI: 10.1002/anie.202107253] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 08/13/2021] [Indexed: 12/15/2022]
Abstract
A reagent‐controlled stereodivergent carbocyclisation of aryl aldimine‐derived, photocatalytically generated, α‐amino radicals possessing adjacent conjugated alkenes, affording either bicyclic or tetracyclic products, is described. Under net reductive conditions using commercial Hantzsch ester, the α‐amino radical species underwent a single stereoselective cyclisation to give trans‐configured amino‐indane structures in good yield, whereas using a substituted Hantzsch ester as a milder reductant afforded cis‐fused tetracyclic tetrahydroquinoline frameworks, resulting from two consecutive radical cyclisations. Judicious choice of the reaction conditions allowed libraries of both single and dual cyclisation products to be synthesised with high selectivity, notable predictability, and good‐to‐excellent yields. Computational analysis employing DFT revealed the reaction pathway and mechanistic rationale behind this finely balanced yet readily controlled photocatalytic system.
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Affiliation(s)
- J Andrew P Maitland
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford, OX1 3TA, UK
| | - Jamie A Leitch
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford, OX1 3TA, UK.,Current address: Department of Pharmaceutical and Biological Chemistry, UCL (University College London), School of Pharmacy, 29-39 Brunswick Square, London, WC1N 1AX, UK
| | - Ken Yamazaki
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford, OX1 3TA, UK.,Department of Theoretical Chemistry, Amsterdam Institute of Molecular and Life Sciences (AIMMS), Amsterdam Center for Multiscale Modeling (ACMM), Vrije Universiteit Amsterdam, De Boelelaan 1083, 1081 HV, Amsterdam, The Netherlands
| | - Kirsten E Christensen
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford, OX1 3TA, UK
| | | | - Trevor A Hamlin
- Department of Theoretical Chemistry, Amsterdam Institute of Molecular and Life Sciences (AIMMS), Amsterdam Center for Multiscale Modeling (ACMM), Vrije Universiteit Amsterdam, De Boelelaan 1083, 1081 HV, Amsterdam, The Netherlands
| | - Darren J Dixon
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford, OX1 3TA, UK
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42
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Haughey MB, Christensen KE, Poole DL, Donohoe TJ. Development of an enolate alkynylation approach towards the synthesis of the taiwanschirin natural products. Chem Sci 2021; 12:13392-13397. [PMID: 34777757 PMCID: PMC8528008 DOI: 10.1039/d1sc04247e] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2021] [Accepted: 09/14/2021] [Indexed: 11/26/2022] Open
Abstract
Through the use of model studies, an approach was conceived towards the synthesis of the taiwanschirin family of natural products. These are structurally complex compounds which represent highly challenging and biologically active targets for total synthesis. This work describes a successful synthesis of the complex taiwanschirin fused [8,6,5] core through a novel alkynylation reaction coupled with an intramolecular Heck reaction used to construct the 8-membered ring.
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Affiliation(s)
- Maxwell B Haughey
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory Mansfield Road Oxford OX1 3TA UK
| | - Kirsten E Christensen
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory Mansfield Road Oxford OX1 3TA UK
| | - Darren L Poole
- GlaxoSmithKline Medicines Research Centre Stevenage SG1 2NY UK
| | - Timothy J Donohoe
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory Mansfield Road Oxford OX1 3TA UK
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43
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Smith PJ, Jiang Y, Tong Z, Pickford HD, Christensen KE, Nugent J, Anderson EA. Synthesis of Polysubstituted Fused Pyrroles by Gold-Catalyzed Cycloisomerization/1,2-Sulfonyl Migration of Yndiamides. Org Lett 2021; 23:6547-6552. [PMID: 34369785 DOI: 10.1021/acs.orglett.1c02360] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Yndiamides (bis-N-substituted alkynes) are valuable precursors to azacycles. Here we report a cycloisomerization/1,2-sulfonyl migration of alkynyl-yndiamides to form tetrahydropyrrolopyrroles, unprecedented heterocyclic scaffolds that are relevant to medicinal chemistry. This functional group tolerant transformation can be achieved using Au(I) catalysis that proceeds at ambient temperature, and a thermally promoted process. The utility of the products is demonstrated by a range of reactions to functionalize the fused pyrrole core.
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Affiliation(s)
- Philip J Smith
- Chemistry Research Laboratory, 12 Mansfield Road, Oxford OX1 3TA, U.K
| | - Yubo Jiang
- Faculty of Science, Kunming University of Science and Technology, Kunming 650500, China
| | - Zixuan Tong
- Chemistry Research Laboratory, 12 Mansfield Road, Oxford OX1 3TA, U.K
| | - Helena D Pickford
- Chemistry Research Laboratory, 12 Mansfield Road, Oxford OX1 3TA, U.K
| | | | - Jeremy Nugent
- Chemistry Research Laboratory, 12 Mansfield Road, Oxford OX1 3TA, U.K
| | - Edward A Anderson
- Chemistry Research Laboratory, 12 Mansfield Road, Oxford OX1 3TA, U.K
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44
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Brand M, Clayton J, Moroglu M, Schiedel M, Picaud S, Bluck JP, Skwarska A, Bolland H, Chan AKN, Laurin CMC, Scorah AR, See L, Rooney TPC, Andrews KH, Fedorov O, Perell G, Kalra P, Vinh KB, Cortopassi WA, Heitel P, Christensen KE, Cooper RI, Paton RS, Pomerantz WCK, Biggin PC, Hammond EM, Filippakopoulos P, Conway SJ. Controlling Intramolecular Interactions in the Design of Selective, High-Affinity Ligands for the CREBBP Bromodomain. J Med Chem 2021; 64:10102-10123. [PMID: 34255515 PMCID: PMC8311651 DOI: 10.1021/acs.jmedchem.1c00348] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
![]()
CREBBP (CBP/KAT3A)
and its paralogue EP300 (KAT3B) are lysine acetyltransferases
(KATs) that are essential for human development. They each comprise
10 domains through which they interact with >400 proteins, making
them important transcriptional co-activators and key nodes in the
human protein–protein interactome. The bromodomains of CREBBP
and EP300 enable the binding of acetylated lysine residues from histones
and a number of other important proteins, including p53, p73, E2F,
and GATA1. Here, we report a work to develop a high-affinity, small-molecule
ligand for the CREBBP and EP300 bromodomains [(−)-OXFBD05]
that shows >100-fold selectivity over a representative member of
the
BET bromodomains, BRD4(1). Cellular studies using this ligand demonstrate
that the inhibition of the CREBBP/EP300 bromodomain in HCT116 colon
cancer cells results in lowered levels of c-Myc and a reduction in
H3K18 and H3K27 acetylation. In hypoxia (<0.1% O2),
the inhibition of the CREBBP/EP300 bromodomain results in the enhanced
stabilization of HIF-1α.
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Affiliation(s)
- Michael Brand
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Mansfield Road, Oxford OX1 3TA, U.K
| | - James Clayton
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Mansfield Road, Oxford OX1 3TA, U.K
| | - Mustafa Moroglu
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Mansfield Road, Oxford OX1 3TA, U.K
| | - Matthias Schiedel
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Mansfield Road, Oxford OX1 3TA, U.K
| | - Sarah Picaud
- Nuffield Department of Clinical Medicine, Structural Genomics Consortium, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 3TA, U.K
| | - Joseph P Bluck
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Mansfield Road, Oxford OX1 3TA, U.K.,Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, U.K
| | - Anna Skwarska
- Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford OX3 7DQ, U.K
| | - Hannah Bolland
- Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford OX3 7DQ, U.K
| | - Anthony K N Chan
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Mansfield Road, Oxford OX1 3TA, U.K
| | - Corentine M C Laurin
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Mansfield Road, Oxford OX1 3TA, U.K
| | - Amy R Scorah
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Mansfield Road, Oxford OX1 3TA, U.K
| | - Larissa See
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Mansfield Road, Oxford OX1 3TA, U.K
| | - Timothy P C Rooney
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Mansfield Road, Oxford OX1 3TA, U.K
| | - Katrina H Andrews
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Mansfield Road, Oxford OX1 3TA, U.K
| | - Oleg Fedorov
- Nuffield Department of Clinical Medicine, Structural Genomics Consortium, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 3TA, U.K
| | - Gabriella Perell
- Department of Chemistry, University of Minnesota, 207 Pleasant Street SE, Minneapolis, Minnesota 55455, United States
| | - Prakriti Kalra
- Department of Chemistry, University of Minnesota, 207 Pleasant Street SE, Minneapolis, Minnesota 55455, United States
| | - Kayla B Vinh
- Department of Chemistry, University of Minnesota, 207 Pleasant Street SE, Minneapolis, Minnesota 55455, United States
| | - Wilian A Cortopassi
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Mansfield Road, Oxford OX1 3TA, U.K
| | - Pascal Heitel
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Mansfield Road, Oxford OX1 3TA, U.K
| | - Kirsten E Christensen
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Mansfield Road, Oxford OX1 3TA, U.K
| | - Richard I Cooper
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Mansfield Road, Oxford OX1 3TA, U.K
| | - Robert S Paton
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Mansfield Road, Oxford OX1 3TA, U.K.,Department of Chemistry, Colorado State University, 1301 Center Ave, Ft. Collins, Colorado 80523-1872, United States
| | - William C K Pomerantz
- Department of Chemistry, University of Minnesota, 207 Pleasant Street SE, Minneapolis, Minnesota 55455, United States
| | - Philip C Biggin
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, U.K
| | - Ester M Hammond
- Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford OX3 7DQ, U.K
| | - Panagis Filippakopoulos
- Nuffield Department of Clinical Medicine, Structural Genomics Consortium, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 3TA, U.K
| | - Stuart J Conway
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Mansfield Road, Oxford OX1 3TA, U.K
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45
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Yao K, Karunanithy G, Howarth A, Holdship P, Thompson AL, Christensen KE, Baldwin AJ, Faulkner S, Farrer NJ. Cell-permeable lanthanide-platinum(IV) anti-cancer prodrugs. Dalton Trans 2021; 50:8761-8767. [PMID: 34080595 PMCID: PMC8237448 DOI: 10.1039/d1dt01688a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Accepted: 05/28/2021] [Indexed: 11/23/2022]
Abstract
Platinum compounds are a vital part of our anti-cancer arsenal, and determining the location and speciation of platinum compounds is crucial. We have synthesised a lanthanide complex bearing a salicylic group (Ln = Gd, Eu) which demonstrates excellent cellular accumulation and minimal cytotoxicity. Derivatisation enabled access to bimetallic lanthanide-platinum(ii) and lanthanide-platinum(iv) complexes. Luminescence from the europium-platinum(iv) system was quenched, and reduction to platinum(ii) with ascorbic acid resulted in a "switch-on" luminescence enhancement. We used diffusion-based 1H NMR spectroscopic methods to quantify cellular accumulation. The gadolinium-platinum(ii) and gadolinium-platinum(iv) complexes demonstrated appreciable cytotoxicity. A longer delay following incubation before cytotoxicity was observed for the gadolinium-platinum(iv) compared to the gadolinium-platinum(ii) complex. Functionalisation with octanoate ligands resulted in enhanced cellular accumulation and an even greater latency in cytotoxicity.
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Affiliation(s)
- Kezi Yao
- Chemistry Research Laboratory, University of Oxford, Mansfield Road, OX1 3TA, UK.
| | - Gogulan Karunanithy
- Chemistry Research Laboratory, University of Oxford, Mansfield Road, OX1 3TA, UK.
| | - Alison Howarth
- Chemistry Research Laboratory, University of Oxford, Mansfield Road, OX1 3TA, UK.
| | - Philip Holdship
- Department of Earth Sciences, University of Oxford, OX1 3AN, UK
| | - Amber L Thompson
- Chemistry Research Laboratory, University of Oxford, Mansfield Road, OX1 3TA, UK.
| | | | - Andrew J Baldwin
- Chemistry Research Laboratory, University of Oxford, Mansfield Road, OX1 3TA, UK.
| | - Stephen Faulkner
- Chemistry Research Laboratory, University of Oxford, Mansfield Road, OX1 3TA, UK.
| | - Nicola J Farrer
- Chemistry Research Laboratory, University of Oxford, Mansfield Road, OX1 3TA, UK.
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46
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McNamee RE, Haugland MM, Nugent J, Chan R, Christensen KE, Anderson EA. Synthesis of 1,3-disubstituted bicyclo[1.1.0]butanes via directed bridgehead functionalization. Chem Sci 2021; 12:7480-7485. [PMID: 34163838 PMCID: PMC8171340 DOI: 10.1039/d1sc01836a] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Bicyclo[1.1.0]butanes (BCBs) are increasingly valued as intermediates in ‘strain release’ chemistry for the synthesis of substituted four membered rings and bicyclo[1.1.1]pentanes, with applications including bioconjugation processes. Variation of the BCB bridgehead substituents can be challenging due to the inherent strain of the bicyclic scaffold, often necessitating linear syntheses of specific BCB targets. Here we report the first palladium catalyzed cross-coupling on pre-formed BCBs which enables a ‘late stage’ diversification of the bridgehead position, and the conversion of the resultant products into a range of useful small ring building blocks. Bicyclo[1.1.0]butanes (BCBs) are valuable precursors to four-membered rings and bicyclo[1.1.1]pentanes, and useful bioconjugation agents. We describe a versatile approach to access 1,3-disubstituted BCBs, which are otherwise challenging to prepare.![]()
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Affiliation(s)
- Ryan E McNamee
- Chemistry Research Laboratory 12 Mansfield Road Oxford OX1 3TA UK
| | | | - Jeremy Nugent
- Chemistry Research Laboratory 12 Mansfield Road Oxford OX1 3TA UK
| | - Rachel Chan
- Chemistry Research Laboratory 12 Mansfield Road Oxford OX1 3TA UK
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47
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Xu W, Leary E, Hou S, Sangtarash S, González MT, Rubio‐Bollinger G, Wu Q, Sadeghi H, Tejerina L, Christensen KE, Agraït N, Higgins SJ, Lambert CJ, Nichols RJ, Anderson HL. Berichtigung: Unusual Length Dependence of the Conductance in Cumulene Molecular Wires. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202102667] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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48
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Xu W, Leary E, Hou S, Sangtarash S, González MT, Rubio-Bollinger G, Wu Q, Sadeghi H, Tejerina L, Christensen KE, Agraït N, Higgins SJ, Lambert CJ, Nichols RJ, Anderson HL. Corrigendum: Unusual Length Dependence of the Conductance in Cumulene Molecular Wires. Angew Chem Int Ed Engl 2021; 60:9170. [PMID: 33844403 PMCID: PMC8173639 DOI: 10.1002/anie.202102667] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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49
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Frost JR, Cheong CB, Akhtar WM, Caputo DF, Christensen KE, Stevenson NG, Donohoe TJ. Hydrogen borrowing catalysis using 1° and 2° alcohols: Investigation and scope leading to α and β branched products. Tetrahedron 2021. [DOI: 10.1016/j.tet.2021.132051] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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50
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Su G, Thomson CJ, Yamazaki K, Rozsar D, Christensen KE, Hamlin TA, Dixon DJ. A bifunctional iminophosphorane squaramide catalyzed enantioselective synthesis of hydroquinazolines via intramolecular aza-Michael reaction to α,β-unsaturated esters. Chem Sci 2021; 12:6064-6072. [PMID: 33996002 PMCID: PMC8098679 DOI: 10.1039/d1sc00856k] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
An efficient synthesis of enantioenriched hydroquinazoline cores via a novel bifunctional iminophosphorane squaramide catalyzed intramolecular aza-Michael reaction of urea-linked α,β-unsaturated esters is described. The methodology exhibits a high degree of functional group tolerance around the forming hydroquinazoline aryl core and wide structural variance on the nucleophilic N atom of the urea moiety. Excellent yields (up to 99%) and high enantioselectivities (up to 97 : 3 er) using both aromatic and less acidic aliphatic ureas were realized. The potential industrial applicability of the transformation was demonstrated in a 20 mmol scale-up experiment using an adjusted catalyst loading of 2 mol%. The origin of enantioselectivity and reactivity enhancement provided by the squaramide motif has been uncovered computationally using density functional theory (DFT) calculations, combined with the activation strain model (ASM) and energy decomposition analysis (EDA). The activation of both aromatic and aliphatic ureas as N-centered nucleophiles in intramolecular Michael addition reactions to α,β-unsaturated esters was achieved under bifunctional iminophosphorane squaramide superbase catalysis.![]()
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Affiliation(s)
- Guanglong Su
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford Mansfield Road Oxford OX1 3TA UK
| | - Connor J Thomson
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford Mansfield Road Oxford OX1 3TA UK
| | - Ken Yamazaki
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford Mansfield Road Oxford OX1 3TA UK .,Department of Theoretical Chemistry, Amsterdam Institute of Molecular and Life Sciences (AIMMS), Amsterdam Center for Multiscale Modeling (ACMM), Vrije Universiteit Amsterdam De Boelelaan 1083, 1081 HV Amsterdam The Netherlands
| | - Daniel Rozsar
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford Mansfield Road Oxford OX1 3TA UK
| | - Kirsten E Christensen
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford Mansfield Road Oxford OX1 3TA UK
| | - Trevor A Hamlin
- Department of Theoretical Chemistry, Amsterdam Institute of Molecular and Life Sciences (AIMMS), Amsterdam Center for Multiscale Modeling (ACMM), Vrije Universiteit Amsterdam De Boelelaan 1083, 1081 HV Amsterdam The Netherlands
| | - Darren J Dixon
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford Mansfield Road Oxford OX1 3TA UK
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