Cobalt-catalyzed C-H allylation reactions of NH-free benzimidates using vinylcyclopropanes or allyl carbonate are reported. The reactive and relatively unstable imidate groups remain intact during the C-H allylations to afford functionalized imidates without dealcoholizations. The thus obtained allylated imidate was subsequently converted into other heterocyclic structures through a following C-H functionalization reaction, demonstrating the synthetic utility of this method.
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http://dx.doi.org/10.1021/acs.joc.9b01972 | DOI Listing |
J Am Chem Soc
January 2025
Department of Chemistry, University of Houston, Houston, Texas 77204-5003, United States.
Monoanionic, bidentate-auxiliary-directed, cobalt-catalyzed C-H bond functionalization has become a very useful tool in organic synthesis. A comprehensive investigation into isolated organometallic intermediates and their reactivity within the catalytic cycle is lacking. We report here mechanistic studies of cobalt-catalyzed, aminoquinoline-directed C(sp)-H bond functionalization.
View Article and Find Full Text PDFJ Org Chem
January 2025
Collaborative Innovation Center for Advanced Organic Chemical Materials Co-Constructed by the Province and Ministry, Ministry of Education Key Laboratory for the Synthesis and Application of Organic Functional Molecules, Hubei Key Laboratory for Precision Synthesis of Small Molecule Pharmaceuticals, College of Chemistry and Chemical Engineering, Hubei University, Wuhan 430062, P. R. China.
Direct functionalization of native (N-H) indoles via C-H activation remains a challenge. Herein, we report a salicylaldehyde-promoted cobalt-catalyzed selective C2-H Heck reaction of native (N-H) indoles with both active and unactivated olefins in the presence of free N-H bonds. A series of structurally diverse C2-alkenylated native (N-H) indoles including natural product and drug derivatives were prepared directly and effectively without additional preprotection and deprotection procedures.
View Article and Find Full Text PDFJ Org Chem
December 2024
Natural Products and Green Chemistry Division, Central Salt and Marine Chemicals Research Institute (CSIR), G. B. Marg, Bhavnagar 364002, Gujarat, India.
A simple cobalt-catalyzed, picolinamide-directed C8-H sulfoxamination of 1-naphthalamides with NH-sulfoximines has been developed. This cross-dehydrogenative C-H/N-H coupling reaction offers a facile route to N-arylated sulfoximines, exhibiting high yields, a broad substrate scope, and excellent functional group tolerance and scalability.
View Article and Find Full Text PDFOrg Lett
November 2024
Latvian Institute of Organic Synthesis, Aizkraukles Street 21, LV-1006 Riga, Latvia.
Herein, we report a simple method for the synthesis of 3-benzazepine derivatives via a cobalt-catalyzed, picolinamide-directed α-amidoacrylate C(sp)-H bond functionalization approach. The reactions utilize calcium carbide as an inexpensive, easy-to-handle, and solid acetylene source, and simple CoCl as the reaction catalyst. Excellent functional group tolerance is observed, yielding diverse substituted 3-benzazepine derivatives in good to excellent yields.
View Article and Find Full Text PDFOrg Lett
October 2024
Jiangsu Key Laboratory of Neuropsychiatric Diseases and Department of Medicinal Chemistry, College of Pharmaceutical Sciences, Soochow University, 199 Ren-Ai Road, Suzhou, Jiangsu 215123, China.
Cobalt-catalyzed enantioconvergent cross-coupling of C(sp)-H bonds with -generated sulfenate anions is achieved to access chiral sulfoxides, which are found in the structures of many biologically active agents. The more challenging aliphatic C-H bonds as well as sterically hindered substrates containing tertiary C-H bonds could also be tolerated well. Mechanistic studies indicate that the transformation could undergo a CoS(O)R-mediated single-electron transfer with -fluorocarboxamides, followed by a 1,5-hydrogen atom transfer and then a pivotal organocobalt(IV)-controlled enantioselective cross-coupling process.
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