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Abstract
This manuscript details the development of a general and mild protocol for the α-C-H cyanation of tertiary amines and its application in late-stage functionalization. Suitable substrates include tertiary aliphatic, benzylic, and aniline-type substrates and complex substrates. Functional groups tolerated under the reaction conditions include various heterocycles and ketones, amides, olefins, and alkynes. This broad substrate scope is remarkable, as comparable reaction protocols for α-C-H cyanation frequently occur via free radical mechanisms and are thus fundamentally limited in their functional group tolerance. In contrast, the presented catalyst system tolerates functional groups that typically react with free radicals, suggesting an alternative reaction pathway. All components of the described catalyst system are readily available, allowing implementation of the presented methodology without the need for lengthy catalyst synthesis.
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A dual light-driven palladium catalyst: Breaking the barriers in carbonylation reactions. Science 2020; 368:318-323. [DOI: 10.1126/science.aba5901] [Citation(s) in RCA: 107] [Impact Index Per Article: 26.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Accepted: 03/16/2020] [Indexed: 12/21/2022]
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3
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4
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NaBrO3/bmim[HSO4]: a versatile system for the selective oxidation of 1,2-diols, α-hydroxyketones, and alcohols. MONATSHEFTE FUR CHEMIE 2016. [DOI: 10.1007/s00706-016-1749-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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5
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Multifunctional Homopolymers: Postpolymerization Modification via Sequential Nucleophilic Aromatic Substitution. Macromolecules 2016. [DOI: 10.1021/acs.macromol.6b00181] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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6
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Silica-Supported Oligomeric Benzyl Phosphate (Si-OBP) and Triazole Phosphate (Si-OTP) Alkylating Reagents. J Org Chem 2015; 80:9942-50. [PMID: 26430955 PMCID: PMC4848109 DOI: 10.1021/acs.joc.5b01456] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The syntheses of silica-supported oligomeric benzyl phosphates (Si-OBP(n)) and triazole phosphates (Si-OTP(n)) using ring-opening metathesis polymerization (ROMP) for use as efficient alkylating reagents is reported. Ease of synthesis and grafting onto the surface of norbornenyl-tagged (Nb-tagged) silica particles has been demonstrated for benzyl phosphate and triazole phosphate monomers. It is shown that these silica polymer hybrid reagents, Si-OBP(n) and Si-OTP(n), can be used to carry out alkylation reactions with an array of different nucleophiles to afford the corresponding benzylated and (triazolyl)methylated products in good yield and high purity.
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Synthesis of 7-norbornenols via Diels–Alder cycloadditions of cyclopentadienol generated by decomposition of ferrocenium cation. Tetrahedron Lett 2015. [DOI: 10.1016/j.tetlet.2015.09.051] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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8
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Catalytic role of PPh3 and its polymer bound analog in the amidation of carboxylic acids mediated by 2,4,6-trichloro-1,3,5-triazine. Tetrahedron Lett 2015. [DOI: 10.1016/j.tetlet.2015.07.012] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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9
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A mild, copper-catalysed amide deprotection strategy: use of tert-butyl as a protecting group. Tetrahedron 2014. [DOI: 10.1016/j.tet.2014.07.080] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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10
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Reductive Carbonylation of Aryl Halides Employing a Two-Chamber Reactor: A Protocol for the Synthesis of Aryl Aldehydes Including 13C- and D-Isotope Labeling. J Org Chem 2013; 78:6112-20. [DOI: 10.1021/jo400741t] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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11
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Ring-opening metathesis polymerization-based recyclable magnetic acylation reagents. CHEMSUSCHEM 2013; 6:721-729. [PMID: 23427021 DOI: 10.1002/cssc.201200453] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2012] [Revised: 10/10/2012] [Indexed: 06/01/2023]
Abstract
An operationally simple method for the acylation of amines utilizing carbon-coated metal nanoparticles as recyclable supports is reported. Highly magnetic carbon-coated cobalt (Co/C) and iron (Fe/C) nanobeads were functionalized with a norbornene tag (Nb-tag) through a "click" reaction followed by surface activation employing Grubbs-II catalyst and subsequent grafting of acylated N-hydroxysuccinimide ROMPgels (ROMP=ring-opening metathesis polymerization). The high loading (up to 2.6 mmolg(-1) ) hybrid material was applied in the acylation of various primary and secondary amines. The products were isolated in high yields (86-99%) and excellent purities (all >95 % by NMR spectroscopy) after rapid magnetic decantation and simple evaporation of the solvents. The spent resins were successfully re-acylated by acid chlorides, anhydrides, and carboxylic acids and reused for up to five consecutive cycles without considerable loss of activity.
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A direct and mild formylation method for substituted benzenes utilizing dichloromethyl methyl ether-silver trifluoromethanesulfonate. J Org Chem 2013; 78:3438-44. [PMID: 23477294 DOI: 10.1021/jo400056k] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A silver trifluoromethanesulfonate (AgOTf)-promoted direct and mild formylation of benzenes has been developed. The reaction utilizing dichloromethyl methyl ether (Cl2CHOMe) and AgOTf powerfully formylated various substituted benzenes under temperature conditions as low as -78 °C without losing the protecting groups on the phenolic hydroxyl group.
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The direct amidation of α-diketones with amines via TBHP-promoted oxidative cleavage of C(sp2)–C(sp2) bonds. Org Biomol Chem 2013; 11:6772-9. [DOI: 10.1039/c3ob41392f] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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14
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Exploring chemical diversity via a modular reaction pairing strategy. Beilstein J Org Chem 2012; 8:1293-302. [PMID: 23019462 PMCID: PMC3458752 DOI: 10.3762/bjoc.8.147] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2012] [Accepted: 07/09/2012] [Indexed: 12/23/2022] Open
Abstract
The efficient synthesis of an 80-member library of unique benzoxathiazocine 1,1-dioxides by a microwave-assisted, intermolecular nucleophilic aromatic substitution (SNAr) diversification pathway is reported. Eight benzofused sultam cores were generated by means of a sulfonylation/SNAr/Mitsunobu reaction pairing protocol, and subsequently diversified by intermolecular SNAr with ten chiral, non-racemic amine/amino alcohol building blocks. Computational analyses were employed to explore and evaluate the chemical diversity of the library.
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Synthesis and applications of Fe3O4-diisopropylaminoacetamide as a versatile and reusable magnetic nanoparticle supported N,N-diisopropylethylamine equivalent. Tetrahedron Lett 2012. [DOI: 10.1016/j.tetlet.2012.03.063] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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16
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Intensified Azeotropic Distillation: A Strategy for Optimizing Direct Amidation. Org Process Res Dev 2012. [DOI: 10.1021/op300058f] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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17
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Facile (triazolyl)methylation of MACOS-derived benzofused sultams utilizing ROMP-derived OTP reagents. ACS COMBINATORIAL SCIENCE 2012; 14:268-72. [PMID: 22384820 DOI: 10.1021/co2001839] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
A combination of MACOS scale-out and ROMP-derived oligomeric triazole phosphates (OTP(n)) have been successfully utilized for the preparation of a 106-member library of triazole containing benzothiaoxazepine-1,1-dioxides. This report demonstrates the utilization of a suite of soluble OTP(n) reagents for facile (triazolyl)methylation of 10 MACOS-derived sultam scaffolds in purification-free process for parallel synthesis of small molecule collections for HTS.
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Synthesis of amino-benzothiaoxazepine-1,1-dioxides utilizing a microwave-assisted, S(N)Ar protocol. ACS COMBINATORIAL SCIENCE 2011; 13:653-8. [PMID: 21902243 DOI: 10.1021/co200076j] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The development of a microwave-assisted, intermolecular S(N)Ar protocol for the synthesis of a 126-member benzothiaoxazepine-1,1-dioxide library is reported. Diversification of 12 benzothiaoxazepine-1,1-dioxides was achieved in rapid fashion utilizing a variety of 2° amines and amino alcohols to generate an 80-member library. A second 48-member library was subsequently generated via a two-step alkylation, intermolecular S(N)Ar diversification protocol.
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An Efficient Protocol for the Amidation of Carboxylic Acids Promoted by Trimethyl Phosphite and Iodine. European J Org Chem 2011. [DOI: 10.1002/ejoc.201101030] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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Synthesis of epoxybenzo[d]isothiazole 1,1-dioxides via a reductive-Heck, metathesis-sequestration protocol. Chem Commun (Camb) 2011; 47:9528-30. [PMID: 21727956 PMCID: PMC3271945 DOI: 10.1039/c1cc12503f] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
An atom-economical purification protocol, using solution phase processing via ring-opening metathesis polymerization (ROMP) has been developed for the synthesis of tricyclic sultams. This chromatography-free method allows for convenient isolation of reductive-Heck products and reclamation of excess starting material via sequestration involving metathesis catalysts and a catalyst-armed Si-surface.
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"Click"-capture, ring-opening metathesis polymerization (ROMP), release: facile triazolation utilizing ROMP-derived oligomeric phosphates. Org Lett 2011; 13:2038-41. [PMID: 21434675 PMCID: PMC3098766 DOI: 10.1021/ol200430c] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Soluble, high-load ring-opening metathesis polymerization (ROMP)-derived oligomeric triazole phosphates (OTP) are reported for application as efficient triazolating reagents of nucleophilic species. Utilizing a "Click"-capture, ROMP, release protocol, the efficient and purification-free, direct triazolation of N-, O-, and S-nucleophilic species was successfully achieved. A variety of OTP derivatives were rapidly synthesized as free-flowing solids on a multigram scale from commercially available materials.
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Monomer-on-monomer (MoM) Mitsunobu reaction: facile purification utilizing surface-initiated sequestration. Org Lett 2011; 13:8-10. [PMID: 21121636 PMCID: PMC3271942 DOI: 10.1021/ol1022382] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
A monomer-on-monomer (MoM) Mitsunobu reaction utilizing norbornenyl-tagged (Nb-tagged) reagents is reported, whereby purification was rapidly achieved by employing ring-opening metathesis polymerization, which was initiated by any of three methods utilizing Grubbs catalyst: (i) free catalyst in solution, (ii) surface-initiated catalyst-armed silica, or (iii) surface-initiated catalyst-armed Co/C magnetic nanoparticles.
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Abstract
The combination of norbornenyl-tagged (Nb-tagged) silica particles and functionalized Nb-tagged monomers for the generation of hybrid Si-ROMP reagents and scavengers is reported. Specifically Si-ROMP-derived bis-acid chloride, dichlorotriazine, and triphenylphosphine scavenger/reagents have been grafted from the surface of silica particles utilizing surface-initiated, ring-opening metathesis polymerization (ROMP). These hybrid polymeric materials combine the physical properties of current immobilized silica reagents and represent a key advancement in load by merging the inherent tunable properties of the ROMP-derived oligomers with silica supports for application in a parallel synthesis.
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Synthesis of reactive poly(norbornene): Ring‐opening metathesis polymerization of norbornene monomer bearing cyclic dithiocarbonate moiety. ACTA ACUST UNITED AC 2011. [DOI: 10.1002/pola.24523] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Immobilization on a Nanomagnetic Co/C Surface Using ROM Polymerization: Generation of a Hybrid Material as Support for a Recyclable Palladium Catalyst. ADVANCED FUNCTIONAL MATERIALS 2010; 20:4323-4328. [PMID: 22308111 PMCID: PMC3271946 DOI: 10.1002/adfm.201000959] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
A novel hybrid material is reported as support for a recyclable palladium catalyst via surface immobilization of a ligand onto Co-based magnetic nanoparticles (NPs). A standard "click" reaction is utilized to covalently attach a norbornene tag (Nb-tag) to the surface of the carbon coated cobalt NPs. The hybrid magnetic nanoparticles are produced by initiating polymerization of a mixture containing both Nb-tagged ligand (Nb-tagged PPh (3)) and Nb-tagged carbon coated cobalt NPs. In turn, the norbornene units are suitably functionalized to serve as ligands for metal catalysts. A composite material is thus obtained which furnishes a loading that is one order of magnitude higher than the value obtained previously for the synthesis of functionalized Co/C-nanopowders. This allows for its application as a hybrid support with high local catalyst concentrations, as demonstrated for the immobilization of a highly active and recyclable palladium complex for Suzuki-Miyaura cross-coupling reactions. Due to the explicit magnetic moment of the cobalt- NPs, the overall magnetization of this organic/inorganic framework is significantly higher than of polymer coated iron oxide nanoparticles with comparable metal content, hence, its rapid separation from the reaction mixture and recycling via an external magnetic field is not hampered by the functionalized polymer shell.
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S(N)Ar-based, facile synthesis of a library of benzothiaoxazepine-1,1'-dioxides. ACTA ACUST UNITED AC 2010; 12:850-4. [PMID: 20879738 DOI: 10.1021/cc1001023] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The construction of a library of benzothiaoxazepine-1,1'-dioxides utilizing a one-pot, S(N)Ar diversification-ODCT(50) scavenging protocol is reported. This protocol combines microwave irradiation to facilitate the reaction, in conjunction with a soluble ROMP-derived scavenger (ODCT) to afford the desired products in good overall purity. Utilizing this protocol, a 78-member library was successfully synthesized and submitted for biological evaluation.
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Abstract
The development of new ROMP-based oligomeric benzyl phosphates (OBP(n)) is reported for use as soluble, stable benzylating reagents. These oligomeric reagents are readily synthesized from commercially available materials and conveniently polymerized and purified in a one-pot process, affording bench-stable, pure white, free-flowing solids on multigram scale. Utilization in benzylation reactions with a variety of nucleophiles is reported.
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Abstract
A formal [4+3] epoxide cascade protocol utilizing ambiphilic sulfonamides and a variety of epoxides (masked ambiphiles) has been developed for the generation of benzothiaoxazepine-1,1'-dioxides and oxathiazepine-1,1'-dioxides. This protocol combines an epoxide ring-opening with either an S(N)Ar or oxa-Michael cyclization pathway.
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The chemistry of the carbon-transition metal double and triple bond: Annual survey covering the year 2008. Coord Chem Rev 2010. [DOI: 10.1016/j.ccr.2009.07.018] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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30
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Synthetic studies of neoclerodane diterpenes from Salvia divinorum: role of the furan in affinity for opioid receptors. Org Biomol Chem 2009; 7:3748-56. [PMID: 19707679 DOI: 10.1039/b905148a] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Further synthetic modification of the furan ring of salvinorin A (1), the major active component of Salvia divinorum, has resulted in novel neoclerodane diterpenes with opioid receptor affinity and activity. A computational study has predicted 1 to be a reproductive toxicant in mammals and is suggestive that use of 1 may be associated with adverse effects. We report in this study that piperidine 21 and thiomorpholine 23 have been identified as selective partial agonists at kappa opioid receptors. This indicates that additional structural modifications of 1 may provide ligands with good selectivity for opioid receptors but with reduced potential for toxicity.
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