1
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Smith LB, Armstrong RJ, Hou J, Smith E, Sze M, Sterling AJ, Smith A, Duarte F, Donohoe TJ. Redox Reorganization: Aluminium Promoted 1,5-Hydride Shifts Allow the Controlled Synthesis of Multisubstituted Cyclohexenes. Angew Chem Int Ed Engl 2023; 62:e202307424. [PMID: 37358307 PMCID: PMC10953022 DOI: 10.1002/anie.202307424] [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: 05/26/2023] [Revised: 06/21/2023] [Accepted: 06/26/2023] [Indexed: 06/27/2023]
Abstract
An efficient synthesis of cyclohexenes has been achieved from easily accessible tetrahydropyrans via a tandem 1,5-hydride shift-aldol condensation. We discovered that readily available aluminium reagents, e.g. Al2 O3 or Al(Ot Bu)3 are essential for this process, promoting the 1,5-hydride shift with complete regio- and enantiospecificity (in stark contrast to results obtained under basic conditions). The mild conditions, coupled with multiple methods available to access the tetrahydropyran starting materials makes this a versatile method with exceptional functional group tolerance. A wide range of cyclohexenes (>40 examples) have been prepared, many in enantiopure form, showing our ability to selectively install a substituent at each position around the newly forged cyclohexene ring. Experimental and computational studies revealed that aluminium serves a dual role in facilitating the hydride shift, activating both the alkoxide nucleophile and the electrophilic carbonyl group.
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Affiliation(s)
- Lewis B. Smith
- Chemistry Research LaboratoryUniversity of OxfordOX1 3TAOxfordUK
| | - Roly J. Armstrong
- Chemistry Research LaboratoryUniversity of OxfordOX1 3TAOxfordUK
- School of Natural and Environmental SciencesNewcastle UniversityNE1 7RUNewcastle Upon TyneUK
| | - Jingyan Hou
- Chemistry Research LaboratoryUniversity of OxfordOX1 3TAOxfordUK
| | - Edward Smith
- Chemistry Research LaboratoryUniversity of OxfordOX1 3TAOxfordUK
| | - Ming Sze
- Chemistry Research LaboratoryUniversity of OxfordOX1 3TAOxfordUK
| | | | - Alex Smith
- Syngenta, Jealott's Hill International Research CentreRG42 6EYBracknellBerkshireUK
| | - Fernanda Duarte
- Chemistry Research LaboratoryUniversity of OxfordOX1 3TAOxfordUK
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2
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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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3
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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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4
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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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5
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Kratena N, Marinic B, Donohoe TJ. Recent advances in the dearomative functionalisation of heteroarenes. Chem Sci 2022; 13:14213-14225. [PMID: 36545133 PMCID: PMC9749106 DOI: 10.1039/d2sc04638e] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [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: 08/19/2022] [Accepted: 11/04/2022] [Indexed: 11/18/2022] Open
Abstract
Dearomatisation reactions of (hetero)arenes have been widely employed as efficient methods to obtain highly substituted saturated cyclic compounds for over a century. In recent years, research in this area has shifted towards effecting additional C-C bond formation during the overall dearomative process. Moving away from classical hydrogenation-based strategies a wide range of reagents were found to be capable of initiating dearomatisation through nucleophilic addition (typically a reduction) or photochemically induced radical addition. The dearomatisation process gives rise to reactive intermediates which can be intercepted in an intra- or intermolecular fashion to deliver products with significantly increased molecular complexity when compared to simple dearomatisation. In this Perspective recent examples and strategies for the dearomative functionalisation of heteroaromatic systems will be discussed.
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Affiliation(s)
- Nicolas Kratena
- Chemistry Research Laboratory, University of Oxford 12 Mansfield Road Oxford OX1 3TA UK
| | - Bruno Marinic
- Chemistry Research Laboratory, University of Oxford 12 Mansfield Road Oxford OX1 3TA UK
| | - Timothy J Donohoe
- Chemistry Research Laboratory, University of Oxford 12 Mansfield Road Oxford OX1 3TA UK
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6
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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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7
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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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8
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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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9
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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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10
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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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11
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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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12
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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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13
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Hall CJJ, Goundry WRF, Donohoe TJ. Hydrogen-Borrowing Alkylation of 1,2-Amino Alcohols in the Synthesis of Enantioenriched γ-Aminobutyric Acids. Angew Chem Int Ed Engl 2021; 60:6981-6985. [PMID: 33561302 PMCID: PMC8048514 DOI: 10.1002/anie.202100922] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [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: 01/20/2021] [Indexed: 12/22/2022]
Abstract
For the first time we have been able to employ enantiopure 1,2-amino alcohols derived from abundant amino acids in C-C bond-forming hydrogen-borrowing alkylation reactions. These reactions are facilitated by the use of the aryl ketone Ph*COMe. Racemisation of the amine stereocentre during alkylation can be prevented by the use of sub-stoichiometric base and protection of the nitrogen with a sterically hindered triphenylmethane (trityl) or benzyl group. The Ph* and trityl groups are readily cleaved in one pot to give γ-aminobutyric acid (GABA) products as their HCl salts without further purification. Both steps may be performed in sequence without isolation of the hydrogen-borrowing intermediate, removing the need for column chromatography.
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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
| | - William R F Goundry
- Early Chemical Development, Pharmaceutical Sciences, R&D, AstraZeneca, Macclesfield, SK10 2NA, UK
| | - Timothy J Donohoe
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory, Mansfield Road, Oxford, OX1 3TA, UK
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14
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Abstract
The single point activation of pyridines, using an electron-deficient benzyl group, facilitates the ruthenium-catalysed dearomative functionalisation of a range of electronically diverse pyridine derivatives. This transformation delivers hydroxymethylated piperidines in good yields, allowing rapid access to medicinally relevant small heterocycles. A noteworthy feature of this work is that paraformaldehyde acts as both a hydride donor and an electrophile in the reaction, enabling the use of cheap and readily available feedstock chemicals. Removal of the activating group can be achieved readily, furnishing the free NH compound in only 2 steps. The synthetic utility of the method was illustrated with a synthesis of (±)-Paroxetine. Pyridines can be activated at a single point with a new benzyl group, followed by dearomative functionalisation at C3 using formaldehyde.![]()
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Affiliation(s)
- Bruno Marinic
- Chemistry Research Laboratory, University of Oxford Mansfield Road Oxford OX1 3TA UK
| | - Hamish B Hepburn
- Chemistry Research Laboratory, University of Oxford Mansfield Road Oxford OX1 3TA UK
| | - Alexandru Grozavu
- Chemistry Research Laboratory, University of Oxford Mansfield Road Oxford OX1 3TA UK
| | - Mark Dow
- AstraZeneca Silk Road Macclesfield SK10 2NA UK
| | - Timothy J Donohoe
- Chemistry Research Laboratory, University of Oxford Mansfield Road Oxford OX1 3TA UK
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15
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Kwok T, Hoff O, Armstrong RJ, Donohoe TJ. Control of Absolute Stereochemistry in Transition-Metal-Catalysed Hydrogen-Borrowing Reactions. Chemistry 2020; 26:12912-12926. [PMID: 32297370 PMCID: PMC7589454 DOI: 10.1002/chem.202001253] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Revised: 04/03/2020] [Indexed: 12/20/2022]
Abstract
Hydrogen-borrowing catalysis represents a powerful method for the alkylation of amine or enolate nucleophiles with non-activated alcohols. This approach relies upon a catalyst that can mediate a strategic series of redox events, enabling the formation of C-C and C-N bonds and producing water as the sole by-product. In the majority of cases these reactions have been employed to target achiral or racemic products. In contrast, the focus of this Minireview is upon hydrogen-borrowing-catalysed reactions in which the absolute stereochemical outcome of the process can be controlled. Asymmetric hydrogen-borrowing catalysis is rapidly emerging as a powerful approach for the synthesis of enantioenriched amine and carbonyl containing products and examples involving both C-N and C-C bond formation are presented. A variety of different approaches are discussed including use of chiral auxiliaries, asymmetric catalysis and enantiospecific processes.
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Affiliation(s)
- Timothy Kwok
- Chemistry Research LaboratoryUniversity of OxfordOxfordOX1 3TAUK
| | - Oskar Hoff
- Chemistry Research LaboratoryUniversity of OxfordOxfordOX1 3TAUK
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16
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Kwok T, Hoff O, Armstrong RJ, Donohoe TJ. Frontispiece: Control of Absolute Stereochemistry in Transition‐Metal‐Catalysed Hydrogen‐Borrowing Reactions. Chemistry 2020. [DOI: 10.1002/chem.202085762] [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: 11/08/2022]
Affiliation(s)
- Timothy Kwok
- Chemistry Research Laboratory University of Oxford Oxford OX1 3TA UK
| | - Oskar Hoff
- Chemistry Research Laboratory University of Oxford Oxford OX1 3TA UK
| | - Roly J. Armstrong
- Chemistry Research Laboratory University of Oxford Oxford OX1 3TA UK
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17
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Donohoe TJ, Cheong CB, Frost JR. Pentamethylphenyl (Ph*) and Related Derivatives as Useful Acyl Protecting Groups for Organic Synthesis: A Preliminary Study. Synlett 2020. [DOI: 10.1055/s-0040-1707289] [Citation(s) in RCA: 2] [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: 10/23/2022]
Abstract
AbstractA study of acyl protecting groups derived from the Ph* motif is reported. While initial studies indicated that a variety of functional groups were not compatible with the Br2-mediated cleavage conditions required to release the Ph* group, strategies involving the use of different reagents or a modification of Ph* itself (Ph*OH) were investigated to solve this problem.
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Affiliation(s)
- Timothy J. Donohoe
- Department of Chemistry, University of Oxford, Chemical Research Laboratory
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18
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Grozavu A, Hepburn HB, Bailey EP, Lindsay-Scott PJ, Donohoe TJ. Rhodium catalysed C-3/5 methylation of pyridines using temporary dearomatisation. Chem Sci 2020; 11:8595-8599. [PMID: 34123119 PMCID: PMC8163342 DOI: 10.1039/d0sc02759f] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [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: 01/17/2023] Open
Abstract
Pyridines are ubiquitous aromatic rings used in organic chemistry and are crucial elements of the drug discovery process. Herein we describe a new catalytic method that directly introduces a methyl group onto the aromatic ring; this new reaction is related to hydrogen borrowing, and is notable for its use of the feedstock chemicals methanol and formaldehyde as the key reagents. Conceptually, the C-3/5 methylation of pyridines was accomplished by exploiting the interface between aromatic and non-aromatic compounds, and this allows an oscillating reactivity pattern to emerge whereby normally electrophilic aromatic compounds become nucleophilic in the reaction after activation by reduction. Thus, a set of C-4 functionalised pyridines can be mono or doubly methylated at the C-3/5 positions. Electron poor pyridines can be activated by reduction and then methylated at C3/5 using formaldehyde.![]()
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Affiliation(s)
- Alexandru Grozavu
- Chemistry Research Laboratory, University of Oxford Oxford OX1 3TA UK
| | - Hamish B Hepburn
- Chemistry Research Laboratory, University of Oxford Oxford OX1 3TA UK
| | - Elliot P Bailey
- Chemistry Research Laboratory, University of Oxford Oxford OX1 3TA UK
| | | | - Timothy J Donohoe
- Chemistry Research Laboratory, University of Oxford Oxford OX1 3TA UK
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19
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Wübbolt S, Cheong CB, Frost JR, Christensen KE, Donohoe TJ. A Vinyl Cyclopropane Ring Expansion and Iridium-Catalyzed Hydrogen Borrowing Cascade. Angew Chem Int Ed Engl 2020; 59:11339-11344. [PMID: 32314851 PMCID: PMC7463175 DOI: 10.1002/anie.202003614] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Revised: 03/31/2020] [Indexed: 12/18/2022]
Abstract
A vinyl cyclopropane rearrangement embedded in an iridium-catalyzed hydrogen borrowing reaction enabled the formation of substituted stereo-defined cyclopentanes from Ph* methyl ketone and cyclopropyl alcohols. Mechanistic studies provide evidence for the ring-expansion reaction being the result of a cascade based on oxidation of the cyclopropyl alcohols, followed by aldol condensation with the pentamethyl phenyl-substituted ketone to form an enone containing the vinyl cyclopropane. Subsequent single electron transfer (SET) to this system initiates a rearrangement, and the catalytic cycle is completed by reduction of the new enone. This process allows for the efficient formation of diversely substituted cyclopentanes as well as the construction of complex bicyclic carbon skeletons containing up to four contiguous stereocentres, all with high diastereoselectivity.
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Affiliation(s)
- Simon Wübbolt
- Chemistry Research LaboratoryUniversity of OxfordOxfordOX1 3TAUK
| | | | - James R. Frost
- Chemistry Research LaboratoryUniversity of OxfordOxfordOX1 3TAUK
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20
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Wübbolt S, Cheong CB, Frost JR, Christensen KE, Donohoe TJ. A Vinyl Cyclopropane Ring Expansion and Iridium‐Catalyzed Hydrogen Borrowing Cascade. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202003614] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Affiliation(s)
- Simon Wübbolt
- Chemistry Research Laboratory University of Oxford Oxford OX1 3TA UK
| | - Choon Boon Cheong
- Chemistry Research Laboratory University of Oxford Oxford OX1 3TA UK
| | - James R. Frost
- Chemistry Research Laboratory University of Oxford Oxford OX1 3TA UK
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21
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Smith LB, Armstrong RJ, Matheau-Raven D, Donohoe TJ. Chemo- and Regioselective Synthesis of Acyl-Cyclohexenes by a Tandem Acceptorless Dehydrogenation-[1,5]-Hydride Shift Cascade. J Am Chem Soc 2020; 142:2514-2523. [PMID: 31967814 PMCID: PMC7145340 DOI: 10.1021/jacs.9b12296] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [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: 12/20/2022]
Abstract
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An
atom-economical methodology to access substituted acyl-cyclohexenes
from pentamethylacetophenone and 1,5-diols is described. This process is catalyzed by an
iridium(I) catalyst in conjunction with a bulky electron rich phosphine
ligand (CataCXium A) which favors acceptorless dehydrogenation over
conjugate reduction to the corresponding cyclohexane. The reaction
produces water and hydrogen gas as the sole byproducts and a wide
range of functionalized acyl-cyclohexene products can be synthesized
using this method in very high yields. A series of control experiments
were carried out, which revealed that the process is initiated by
acceptorless dehydrogenation of the diol followed by a redox-neutral
cascade process, which is independent of the iridium catalyst. Deuterium
labeling studies established that the key step of this cascade involves
a novel base-mediated [1,5]-hydride shift. The cyclohexenyl ketone
products could readily be cleaved under mildly acidic conditions to
access a range of valuable substituted cyclohexene derivatives.
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Affiliation(s)
- Lewis B Smith
- Chemistry Research Laboratory , University of Oxford , Mansfield Road , Oxford OX1 3TA , United Kingdom
| | - Roly J Armstrong
- Chemistry Research Laboratory , University of Oxford , Mansfield Road , Oxford OX1 3TA , United Kingdom
| | - Daniel Matheau-Raven
- Chemistry Research Laboratory , University of Oxford , Mansfield Road , Oxford OX1 3TA , United Kingdom
| | - Timothy J Donohoe
- Chemistry Research Laboratory , University of Oxford , Mansfield Road , Oxford OX1 3TA , United Kingdom
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22
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Abstract
The activation of pyridinium salts with electron-withdrawing heterocycles enables an iridium-catalyzed reductive hydroxymethylation reaction to proceed smoothly, facilitating the preparation of useful 3D heteroaryl-substituted functionalized piperidines. The methodology is used to prepare 3-hydroxymethylated analogues of pharmaceutical agents. Mechanistically, formaldehyde acts as both a hydride donor and the electrophile, leading to the formation of two new carbon-hydrogen bonds and one new carbon-carbon bond under relatively mild conditions.
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Affiliation(s)
- Hamish B Hepburn
- 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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23
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Cheang DMJ, Armstrong RJ, Akhtar WM, Donohoe TJ. Enantioconvergent alkylation of ketones with racemic secondary alcohols via hydrogen borrowing catalysis. Chem Commun (Camb) 2020; 56:3543-3546. [DOI: 10.1039/d0cc00767f] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
An enantioconvergent hydrogen borrowing strategy enables the catalytic asymmetric alkylation of ketone enolates with unactivated, racemic secondary alcohols.
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24
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Chamberlain AER, Paterson KJ, Armstrong RJ, Twin HC, Donohoe TJ. A hydrogen borrowing annulation strategy for the stereocontrolled synthesis of saturated aza-heterocycles. Chem Commun (Camb) 2020; 56:3563-3566. [DOI: 10.1039/d0cc00903b] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
A hydrogen borrowing annulation strategy enables the stereocontrolled synthesis of C2, C3 and C4-substituted saturated aza-heterocycles.
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25
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Armstrong RJ, Akhtar WM, Frost JR, Christensen KE, Stevenson NG, Donohoe TJ. Stereoselective synthesis of alicyclic ketones: A hydrogen borrowing approach. Tetrahedron 2019. [DOI: 10.1016/j.tet.2019.130680] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
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26
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Walker JCL, Werrel S, Donohoe TJ. Photochemical Alkene Isomerization for the Synthesis of Polysubstituted Furans and Pyrroles under Neutral Conditions. Chemistry 2019; 25:13114-13118. [PMID: 31390097 DOI: 10.1002/chem.201903590] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Indexed: 11/06/2022]
Abstract
A photochemical approach to polysubstituted heterocycles using UV-induced alkene isomerization is described. The method allows for the synthesis of disubstituted furans and pyrroles under mild and neutral conditions and also provides access to a class of trisubstituted furans pertinent to natural-product synthesis. The method has broad functional-group tolerance and many richly decorated heterocycles have been prepared incorporating functional groups that are unstable under Brønsted and Lewis acidic conditions.
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Affiliation(s)
- Johannes C L Walker
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Oxford, OX1 3TA, UK
| | - Simon Werrel
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Oxford, OX1 3TA, UK
| | - Timothy J Donohoe
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Oxford, OX1 3TA, UK
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27
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Reeves BM, Hepburn HB, Grozavu A, Lindsay-Scott PJ, Donohoe TJ. Transition-Metal-Free Reductive Hydroxymethylation of Isoquinolines. Angew Chem Int Ed Engl 2019; 58:15697-15701. [PMID: 31486205 PMCID: PMC6856840 DOI: 10.1002/anie.201908857] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [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: 07/16/2019] [Revised: 08/23/2019] [Indexed: 01/18/2023]
Abstract
A transition‐metal‐free reductive hydroxymethylation reaction has been developed, enabling the preparation of tetrahydroisoquinolines bearing C4‐quaternary centers from the corresponding isoquinolines. Deuterium labelling studies and control experiments enable a potential mechanism to be elucidated which features a key Cannizzaro‐type reduction followed by an Evans–Tishchenko reaction. When isoquinolines featuring a proton at the 4‐position are used, a tandem methylation‐hydroxymethylation occurs, leading to the formation of 2 new C−C bonds in one pot.
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Affiliation(s)
- Benjamin M Reeves
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory, Mansfield Road, Oxford, OX1 3TA, UK
| | - Hamish B Hepburn
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory, Mansfield Road, Oxford, OX1 3TA, UK
| | - Alexandru Grozavu
- 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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28
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Reeves BM, Hepburn HB, Grozavu A, Lindsay‐Scott PJ, Donohoe TJ. Transition‐Metal‐Free Reductive Hydroxymethylation of Isoquinolines. Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201908857] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Affiliation(s)
- Benjamin M. Reeves
- Department of Chemistry University of Oxford Chemistry Research Laboratory Mansfield Road Oxford OX1 3TA UK
| | - Hamish B. Hepburn
- Department of Chemistry University of Oxford Chemistry Research Laboratory Mansfield Road Oxford OX1 3TA UK
| | - Alexandru Grozavu
- 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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29
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Zhu Y, Colomer I, Donohoe TJ. Hypervalent iodine initiated intramolecular alkene dimerisation: a stereodivergent entry to cyclobutanes. Chem Commun (Camb) 2019; 55:10316-10319. [PMID: 31402367 DOI: 10.1039/c9cc04383g] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The emergence of new methods for the stereoselective synthesis of strained carbocycles is a challenging but worthwhile endeavour. Cyclobutanes, in particular, have attracted the attention of both medicinal chemists and material scientists for their unique properties. Herein, we present a new method that allows access to highly functionalized cyclobutanes with complementary all-trans and trans-cis-trans relative stereochemistry, that could not be accessed before. This approach consists of an intramolecular dimerisation of non-conjugated dienes using an oxidative single electron transfer (SET) process, and is initiated by catalytic amounts of hypervalent iodine reagents. The potential uses of these cyclobutanes is demonstrated with selective functionalization, including the formation of diols and carboxylic acids.
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Affiliation(s)
- Yuxiang Zhu
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory, Mansfield Road, Oxford, OX1 3TA, UK.
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30
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Armstrong RJ, Akhtar WM, Young TA, Duarte F, Donohoe TJ. Catalytic Asymmetric Synthesis of Cyclohexanes by Hydrogen Borrowing Annulations. Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201907514] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
| | - Wasim M. Akhtar
- Chemistry Research LaboratoryUniversity of Oxford Oxford OX1 3TA UK
| | - Tom A. Young
- Chemistry Research LaboratoryUniversity of Oxford Oxford OX1 3TA UK
| | - Fernanda Duarte
- Chemistry Research LaboratoryUniversity of Oxford Oxford OX1 3TA UK
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31
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Armstrong RJ, Akhtar WM, Young TA, Duarte F, Donohoe TJ. Catalytic Asymmetric Synthesis of Cyclohexanes by Hydrogen Borrowing Annulations. Angew Chem Int Ed Engl 2019; 58:12558-12562. [PMID: 31265208 PMCID: PMC6771629 DOI: 10.1002/anie.201907514] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [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: 06/17/2019] [Indexed: 12/17/2022]
Abstract
Hydrogen borrowing catalysis serves as a powerful alternative to enolate alkylation, enabling the direct coupling of ketones with unactivated alcohols. However, to date, methods that enable control over the absolute stereochemical outcome of such a process have remained elusive. Here we report a catalytic asymmetric method for the synthesis of enantioenriched cyclohexanes from 1,5‐diols via hydrogen borrowing catalysis. This reaction is mediated by the addition of a chiral iridium(I) complex, which is able to impart high levels of enantioselectivity upon the process. A series of enantioenriched cyclohexanes have been prepared and the mode of enantioinduction has been probed by a combination of experimental and DFT studies.
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Affiliation(s)
- Roly J Armstrong
- Chemistry Research Laboratory, University of Oxford, Oxford, OX1 3TA, UK
| | - Wasim M Akhtar
- Chemistry Research Laboratory, University of Oxford, Oxford, OX1 3TA, UK
| | - Tom A Young
- Chemistry Research Laboratory, University of Oxford, Oxford, OX1 3TA, UK
| | - Fernanda Duarte
- Chemistry Research Laboratory, University of Oxford, Oxford, OX1 3TA, UK
| | - Timothy J Donohoe
- Chemistry Research Laboratory, University of Oxford, Oxford, OX1 3TA, UK
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32
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Richardson MSW, Tame CJ, Poole DL, Donohoe TJ. Rhodium-catalysed vinyl 1,4-conjugate addition coupled with Sharpless asymmetric dihydroxylation in the synthesis of the CDE ring fragment of pectenotoxin-4. Chem Sci 2019; 10:6336-6340. [PMID: 31341588 PMCID: PMC6601420 DOI: 10.1039/c9sc01761e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [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: 04/10/2019] [Accepted: 05/17/2019] [Indexed: 11/21/2022] Open
Abstract
Rhodium and osmium catalysed C–C and C–O bond formation under mild conditions.
Our synthesis of the CDE ring fragment of pectenotoxin-4 utilised two key steps to make the complex bicyclic ketal unit: (i) a rhodium-catalysed vinyl group 1,4-addition as the major C–C bond forming step; (ii) a stereoselective Sharpless Asymmetric Dihydroxylation (SAD) of the resulting 1,1-disubstituted homoallylic alcohol. Subsequent acid-catalysed cyclisation afforded the desired [5,6]-bicyclic ketal of the target molecule. This methodology was shown to be compatible with the desired E ring fragment 35 in order to construct the CDE fragment 37 of pectenotoxin-4.
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Affiliation(s)
- Melodie S W Richardson
- Department of Chemistry , University of Oxford , Chemistry Research Laboratory , Mansfield Road , Oxford , OX1 3TA , UK .
| | - Christopher J Tame
- GlaxoSmithKline Medicines Research Centre , Gunnels Wood Road , Stevenage , SG1 2NY , UK
| | - Darren L Poole
- GlaxoSmithKline Medicines Research Centre , Gunnels Wood Road , 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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33
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Zhu Y, Colomer I, Thompson AL, Donohoe TJ. HFIP Solvent Enables Alcohols To Act as Alkylating Agents in Stereoselective Heterocyclization. J Am Chem Soc 2019; 141:6489-6493. [DOI: 10.1021/jacs.9b02198] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Yuxiang Zhu
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Mansfield Road, Oxford OX1 3TA, United Kingdom
| | - Ignacio Colomer
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Mansfield Road, Oxford OX1 3TA, United Kingdom
| | - Amber L. Thompson
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Mansfield Road, Oxford OX1 3TA, United Kingdom
| | - Timothy J. Donohoe
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Mansfield Road, Oxford OX1 3TA, United Kingdom
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34
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Shirley HJ, Koyioni M, Muncan F, Donohoe TJ. Synthesis of lamellarin alkaloids using orthoester-masked α-keto acids. Chem Sci 2019; 10:4334-4338. [PMID: 31057760 PMCID: PMC6471603 DOI: 10.1039/c8sc05678a] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [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] [Received: 12/19/2018] [Accepted: 03/07/2019] [Indexed: 12/20/2022] Open
Abstract
Enolate arylation of a protected pyruvate is used as a key step in the short and efficient syntheses of the lamellarins.
Pyruvic acid and other α-keto acids are frequently encountered as intermediates in metabolic pathways, yet their application in total synthesis has met with limited success. In this work, we present a bioinspired strategy that utilizes highly functionalized OBO (oxabicyclo[2.2.2]octyl) orthoester masked α-ketoacids as key intermediates for the construction of both type I and II lamellarin alkaloids. Lamellarin D was synthesized, via a key 1,4-dicarbonyl, in 7 steps and 22% yield from pyruvic acid. Key steps in the synthesis involve one-pot double enolate functionalisation of 1 followed by double annulation to form the target pyrrole/N-vinyl pyrrole core and late-stage direct C–H arylation. Lastly, a novel OBO-masked β-cyano ketone, synthesized from 1, proved to be a valuable intermediate for construction of the type II lamellarin core via HBr-mediated cyclisation. In this way, lamellarin Q was synthesized in 7 steps and 20% yield from pyruvic acid.
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Affiliation(s)
- Harry J Shirley
- Department of Chemistry , University of Oxford , Chemistry Research Laboratory , Mansfield Road , Oxford , OX1 3TA , UK .
| | - Maria Koyioni
- Department of Chemistry , University of Oxford , Chemistry Research Laboratory , Mansfield Road , Oxford , OX1 3TA , UK .
| | - Filip Muncan
- 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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35
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Akhtar WM, Armstrong RJ, Frost JR, Stevenson NG, Donohoe TJ. Stereoselective Synthesis of Cyclohexanes via an Iridium Catalyzed (5 + 1) Annulation Strategy. J Am Chem Soc 2018; 140:11916-11920. [DOI: 10.1021/jacs.8b07776] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- Wasim M. Akhtar
- Department of Chemistry, Chemical Research Laboratory, University of Oxford, Oxford, OX1 3TA, United Kingdom
| | - Roly J. Armstrong
- Department of Chemistry, Chemical Research Laboratory, University of Oxford, Oxford, OX1 3TA, United Kingdom
| | - James R. Frost
- Department of Chemistry, Chemical Research Laboratory, University of Oxford, Oxford, OX1 3TA, United Kingdom
| | - Neil G. Stevenson
- GlaxoSmithKline, Medicines Research Centre, Stevenage, SG1 2NY, United Kingdom
| | - Timothy J. Donohoe
- Department of Chemistry, Chemical Research Laboratory, University of Oxford, Oxford, OX1 3TA, United Kingdom
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36
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Alves Esteves CH, Koyioni M, Christensen KE, Smith PD, Donohoe TJ. OBO-Protected Pyruvates as Reagents for the Synthesis of Functionalized Heteroaromatic Compounds. Org Lett 2018; 20:4048-4051. [DOI: 10.1021/acs.orglett.8b01614] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- C. Henrique Alves Esteves
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory, Mansfield Road, Oxford OX1 3TA, U.K
| | - Maria Koyioni
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory, Mansfield Road, Oxford OX1 3TA, U.K
| | - Kirsten E. Christensen
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory, Mansfield Road, Oxford OX1 3TA, U.K
| | - Peter D. Smith
- Early Chemical Development, Pharmaceutical Sciences, IMED Biotech Unit, AstraZeneca, Macclesfield SK10 2NA, 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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37
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Affiliation(s)
- Sandra Balcells
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory, Mansfield Road, Oxford OX1 3TA, U.K
| | - Maxwell B. Haughey
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory, Mansfield Road, Oxford OX1 3TA, U.K
| | - Johannes C. L. Walker
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory, Mansfield Road, Oxford OX1 3TA, U.K
| | - Laia Josa-Culleré
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory, Mansfield Road, Oxford OX1 3TA, U.K
| | - Christopher Towers
- Department of Oncology, University of Oxford, Old Road Campus Research Building, Roosevelt Drive Oxford OX3 7DQ, 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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38
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Roushanbakhti A, Liu Y, Winship PCM, Tucker MJ, Akhtar WM, Walter DS, Wrigley G, Donohoe TJ. Cobalt versus Osmium: Control of Both trans
and cis
Selectivity in Construction of the EFG Rings of Pectenotoxin 4. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201708278] [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: 11/08/2022]
Affiliation(s)
- Ahria Roushanbakhti
- Department of Chemistry; University of Oxford; Chemistry Research Laboratory; Mansfield Road Oxford OX1 3TA UK
| | - Yifan Liu
- Department of Chemistry; University of Oxford; Chemistry Research Laboratory; Mansfield Road Oxford OX1 3TA UK
| | - Paul C. M. Winship
- Department of Chemistry; University of Oxford; Chemistry Research Laboratory; Mansfield Road Oxford OX1 3TA UK
| | - Michael J. Tucker
- Department of Chemistry; University of Oxford; Chemistry Research Laboratory; Mansfield Road Oxford OX1 3TA UK
| | - Wasim M. Akhtar
- Department of Chemistry; University of Oxford; Chemistry Research Laboratory; Mansfield Road Oxford OX1 3TA UK
| | - Daryl S. Walter
- GlaxoSmithKline Medicines Research Centre; Gunnels Wood Road Stevenage SG1 2NY UK
| | - Gail Wrigley
- AstraZeneca; IMED Oncology; Darwin Building, Unit 310, Cambridge Science Park Cambridge CB4 0WG UK
| | - Timothy J. Donohoe
- Department of Chemistry; University of Oxford; Chemistry Research Laboratory; Mansfield Road Oxford OX1 3TA UK
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39
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Roushanbakhti A, Liu Y, Winship PCM, Tucker MJ, Akhtar WM, Walter DS, Wrigley G, Donohoe TJ. Cobalt versus Osmium: Control of Both trans and cis Selectivity in Construction of the EFG Rings of Pectenotoxin 4. Angew Chem Int Ed Engl 2017; 56:14883-14887. [PMID: 28926175 DOI: 10.1002/anie.201708278] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2017] [Indexed: 11/05/2022]
Abstract
Catalytic oxidative cyclisation reactions have been employed for the synthesis of the E and F rings of the complex natural product target pectenotoxin 4. The choice of metal catalyst (cobalt- or osmium-based) allowed for the formation of THF rings with either trans or cis stereoselectivity. Fragment union using a modified Julia reaction then enabled the synthesis of an advanced synthetic intermediate containing the EF and G rings of the target.
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Affiliation(s)
- Ahria Roushanbakhti
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory, Mansfield Road, Oxford, OX1 3TA, UK
| | - Yifan Liu
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory, Mansfield Road, Oxford, OX1 3TA, UK
| | - Paul C M Winship
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory, Mansfield Road, Oxford, OX1 3TA, UK
| | - Michael J Tucker
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory, Mansfield Road, Oxford, OX1 3TA, UK
| | - Wasim M Akhtar
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory, Mansfield Road, Oxford, OX1 3TA, UK
| | - Daryl S Walter
- GlaxoSmithKline Medicines Research Centre, Gunnels Wood Road, Stevenage, SG1 2NY, UK
| | - Gail Wrigley
- AstraZeneca, IMED Oncology, Darwin Building, Unit 310, Cambridge Science Park, Cambridge, CB4 0WG, UK
| | - Timothy J Donohoe
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory, Mansfield Road, Oxford, OX1 3TA, UK
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40
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Alves Esteves CH, Hall CJJ, Smith PD, Donohoe TJ. Pyruvate Enolate Arylation and Alkylation: OBO Ester Protected Pyruvates as Useful Reagents in Organic Synthesis. Org Lett 2017; 19:5248-5251. [DOI: 10.1021/acs.orglett.7b02524] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- C. Henrique Alves Esteves
- Department
of Chemistry, University of Oxford, Chemistry Research Laboratory, Mansfield
Road, Oxford OX1 3TA, U.K
| | - Christopher J. J. Hall
- Department
of Chemistry, University of Oxford, Chemistry Research Laboratory, Mansfield
Road, Oxford OX1 3TA, U.K
| | - Peter D. Smith
- AstraZeneca, Pharmaceutical Sciences, Silk Road Business Park, Macclesfield SK10 2NA, 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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41
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Abstract
Synthesis of substituted β-carbolines was accomplished by utilizing the catalytic enolate arylation reaction of ketones in conjunction with several 3-bromoindole derivatives. Quenching of the arylation reaction in situ with an electrophile allowed ready incorporation of functionality at the carboline C-4 position in an efficient one-pot protocol.
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Affiliation(s)
- C Henrique Alves Esteves
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory , Mansfield Road, Oxford OX1 3TA, U.K
| | - Peter D Smith
- AstraZeneca, Pharmaceutical Sciences , Silk Road Business Park, Macclesfield SK10 2NA, 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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42
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Akhtar WM, Cheong CB, Frost JR, Christensen KE, Stevenson NG, Donohoe TJ. Hydrogen Borrowing Catalysis with Secondary Alcohols: A New Route for the Generation of β-Branched Carbonyl Compounds. J Am Chem Soc 2017; 139:2577-2580. [PMID: 28177613 DOI: 10.1021/jacs.6b12840] [Citation(s) in RCA: 78] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A hydrogen borrowing reaction employing secondary alcohols and Ph* (Me5C6) ketones to give β-branched carbonyl products is described (21 examples). This new C-C bond forming process requires low loadings of [Cp*IrCl2]2, relatively low temperatures, and up to 2.0 equiv of the secondary alcohol. Substrate-induced diastereoselectivity was observed, and this represents the first example of a diastereoselective enolate hydrogen borrowing alkylation. By utilizing the Ph* group, the β-branched products could be straightforwardly cleaved to the corresponding esters or amides using a retro-Friedel-Crafts reaction. Finally, this protocol was applied to the synthesis of fragrance compound (±)-3-methyl-5-phenylpentanol.
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Affiliation(s)
- Wasim M Akhtar
- Department of Chemistry, Chemical Research Laboratory, University of Oxford , Oxford, OX1 3TA, United Kingdom
| | - Choon Boon Cheong
- Department of Chemistry, Chemical Research Laboratory, University of Oxford , Oxford, OX1 3TA, United Kingdom
| | - James R Frost
- Department of Chemistry, Chemical Research Laboratory, University of Oxford , Oxford, OX1 3TA, United Kingdom
| | - Kirsten E Christensen
- Department of Chemistry, Chemical Research Laboratory, University of Oxford , Oxford, OX1 3TA, United Kingdom
| | - Neil G Stevenson
- GlaxoSmithKline, Medicines Research Centre, Stevenage, SG1 2NY, United Kingdom
| | - Timothy J Donohoe
- Department of Chemistry, Chemical Research Laboratory, University of Oxford , Oxford, OX1 3TA, United Kingdom
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43
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Colomer I, Barcelos RC, Christensen KE, Donohoe TJ. Orthogonally Protected 1,2-Diols from Electron-Rich Alkenes Using Metal-Free Olefin syn-Dihydroxylation. Org Lett 2016; 18:5880-5883. [DOI: 10.1021/acs.orglett.6b02959] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [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)
- Ignacio Colomer
- Department of Chemistry, University of Oxford, Chemistry
Research Laboratory, Mansfield
Road, Oxford, OX1 3TA, U.K
| | - Rosimeire Coura Barcelos
- Department of Chemistry, University of Oxford, Chemistry
Research Laboratory, Mansfield
Road, Oxford, OX1 3TA, 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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44
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Melikhova EY, Pullin RDC, Winter C, Donohoe TJ. Dehydromicrosclerodermin B and Microsclerodermin J: Total Synthesis and Structural Revision. Angew Chem Int Ed Engl 2016; 55:9753-7. [PMID: 27418203 PMCID: PMC5132153 DOI: 10.1002/anie.201604764] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [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: 05/16/2016] [Indexed: 11/08/2022]
Abstract
The total synthesis of dehydromicrosclerodermin B and microsclerodermin J is described. Efficient approaches to the unusual amino acids in the target molecules were developed on the basis of a Negishi coupling (for Trp‐2‐CO2H) and Blaise reaction (for Pyrr). An incorrect assignment of the pyrrolidinone stereochemistry of both compounds was confirmed by synthesizing epimers of the proposed structures. The spectroscopic data of these epimers were in complete agreement with those for the naturally derived material.
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Affiliation(s)
- Ekaterina Y Melikhova
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory, Mansfield Road, Oxford, OX1 3TA, UK
| | - Robert D C Pullin
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory, Mansfield Road, Oxford, OX1 3TA, UK
| | - Christian Winter
- 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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45
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Melikhova EY, Pullin RDC, Winter C, Donohoe TJ. Dehydromicrosclerodermin B and Microsclerodermin J: Total Synthesis and Structural Revision. Angew Chem Int Ed Engl 2016. [DOI: 10.1002/ange.201604764] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Ekaterina Y. Melikhova
- Department of Chemistry; University of Oxford, Chemistry Research Laboratory; Mansfield Road Oxford OX1 3TA UK
| | - Robert D. C. Pullin
- Department of Chemistry; University of Oxford, Chemistry Research Laboratory; Mansfield Road Oxford OX1 3TA UK
| | - Christian Winter
- 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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46
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Colomer I, Batchelor-McAuley C, Odell B, Donohoe TJ, Compton RG. Hydrogen Bonding to Hexafluoroisopropanol Controls the Oxidative Strength of Hypervalent Iodine Reagents. J Am Chem Soc 2016; 138:8855-61. [DOI: 10.1021/jacs.6b04057] [Citation(s) in RCA: 136] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Ignacio Colomer
- Department
of Chemistry, Chemistry Research Laboratory, University of Oxford, Mansfield Road, Oxford OX1 3TA, United Kingdom
| | - Christopher Batchelor-McAuley
- Department
of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom
| | - Barbara Odell
- Department
of Chemistry, Chemistry Research Laboratory, University of Oxford, Mansfield Road, Oxford OX1 3TA, United Kingdom
| | - Timothy J. Donohoe
- Department
of Chemistry, Chemistry Research Laboratory, University of Oxford, Mansfield Road, Oxford OX1 3TA, United Kingdom
| | - Richard G. Compton
- Department
of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom
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47
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Colomer I, Coura Barcelos R, Donohoe TJ. Catalytic Hypervalent Iodine Promoters Lead to Styrene Dimerization and the Formation of Tri- and Tetrasubstituted Cyclobutanes. Angew Chem Int Ed Engl 2016; 55:4748-52. [DOI: 10.1002/anie.201511683] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Revised: 01/26/2016] [Indexed: 11/10/2022]
Affiliation(s)
- Ignacio Colomer
- Department of Chemistry; University of Oxford; Chemistry Research Laboratory; Mansfield Road Oxford OX1 3TA UK
| | - Rosimeire Coura Barcelos
- 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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48
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Colomer I, Coura Barcelos R, Donohoe TJ. Catalytic Hypervalent Iodine Promoters Lead to Styrene Dimerization and the Formation of Tri‐ and Tetrasubstituted Cyclobutanes. Angew Chem Int Ed Engl 2016. [DOI: 10.1002/ange.201511683] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Ignacio Colomer
- Department of Chemistry University of Oxford Chemistry Research Laboratory Mansfield Road Oxford OX1 3TA UK
| | - Rosimeire Coura Barcelos
- 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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49
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Frost JR, Cheong CB, Akhtar WM, Caputo DFJ, Stevenson NG, Donohoe TJ. Strategic Application and Transformation of ortho-Disubstituted Phenyl and Cyclopropyl Ketones To Expand the Scope of Hydrogen Borrowing Catalysis. J Am Chem Soc 2015; 137:15664-7. [DOI: 10.1021/jacs.5b11196] [Citation(s) in RCA: 77] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- James R. Frost
- Department
of Chemistry, Chemistry Research Laboratory, University of Oxford, Oxford OX1 3TA, United Kingdom
| | - Choon Boon Cheong
- Department
of Chemistry, Chemistry Research Laboratory, University of Oxford, Oxford OX1 3TA, United Kingdom
| | - Wasim M. Akhtar
- Department
of Chemistry, Chemistry Research Laboratory, University of Oxford, Oxford OX1 3TA, United Kingdom
| | - Dimitri F. J. Caputo
- Department
of Chemistry, Chemistry Research Laboratory, University of Oxford, Oxford OX1 3TA, United Kingdom
| | - Neil G. Stevenson
- GlaxoSmithkline, Medicines Research Centre, Stevenage SG1 2NY, United Kingdom
| | - Timothy J. Donohoe
- Department
of Chemistry, Chemistry Research Laboratory, University of Oxford, Oxford OX1 3TA, United Kingdom
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50
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Pilgrim BS, Gatland AE, Esteves CHA, McTernan CT, Jones GR, Tatton MR, Procopiou PA, Donohoe TJ. Palladium-catalyzed enolate arylation as a key C-C bond-forming reaction for the synthesis of isoquinolines. Org Biomol Chem 2015; 14:1065-90. [PMID: 26632484 DOI: 10.1039/c5ob02320c] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The palladium-catalyzed coupling of an enolate with an ortho-functionalized aryl halide (an α-arylation) furnishes a protected 1,5-dicarbonyl moiety that can be cyclized to an isoquinoline with a source of ammonia. This fully regioselective synthetic route tolerates a wide range of substituents, including those that give rise to the traditionally difficult to access electron-deficient isoquinoline skeletons. These two synthetic operations can be combined to give a three-component, one-pot isoquinoline synthesis. Alternatively, cyclization of the intermediates with hydroxylamine hydrochloride engenders direct access to isoquinoline N-oxides; and cyclization with methylamine, gives isoquinolinium salts. Significant diversity is available in the substituents at the C4 position in four-component, one-pot couplings, by either trapping the in situ intermediate after α-arylation with carbon or heteroatom-based electrophiles, or by performing an α,α-heterodiarylation to install aryl groups at this position. The α-arylation of nitrile and ester enolates gives access to 3-amino and 3-hydroxyisoquinolines and the α-arylation of tert-butyl cyanoacetate followed by electrophile trapping, decarboxylation and cyclization, C4-functionalized 3-aminoisoquinolines. An oxime directing group can be used to direct a C-H functionalization/bromination, which allows monofunctionalized rather than difunctionalized aryl precursors to be brought through this synthetic route.
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Affiliation(s)
- Ben S Pilgrim
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory, Mansfield Road, Oxford, OX1 3TA, UK.
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