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Iridium-catalyzed selective 1,2-hydrosilylation of N-heterocycles.

ABSTRACT: A silylene-bridged Ir dimer in situ generated from [Ir(coe)₂Cl]₂ and Et₂SiH₂ was found to catalyze the hydrosilylation of N-heteroaromatics to furnish dearomatized azacyclic products with high activity (up to 1000 TONs), excellent selectivity, and good functional group tolerance. The substrate scope was highly broad, including (iso)quinolines, substituted pyridines, pyrimidines, pyrazines, deazapurines, triazines, and benzimidazoles. Mechanistic studies such as a kinetic profile, rate-order assessment, and investigation of the electronic substituent effects on the initial rates were performed to access the detailed pathways. One pathway is proposed to involve an intramolecular insertion of the C[double bond, length as m-dash]N moiety of the substrates into the Ir-H bond of a resting species to form an Ir-amido silyl intermediate, followed by reductive elimination. The synthetic utility was proven by successful application to cinchona alkaloids, and facile post-synthetic transformations of the 1,2-dihydroquinoline products.

SUBMITTER: Jeong J

PROVIDER: S-EPMC6020754 | biostudies-literature | 2016 Aug

REPOSITORIES: biostudies-literature

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Iridium-catalyzed selective 1,2-hydrosilylation of N-heterocycles.

Jeong Jinseong J Park Sehoon S Chang Sukbok S

Chemical science 20160426 8

A silylene-bridged Ir dimer in situ generated from [Ir(coe)2Cl]2 and Et2SiH2 was found to catalyze the hydrosilylation of N-heteroaromatics to furnish dearomatized azacyclic products with high activity (up to 1000 TONs), excellent selectivity, and good functional group tolerance. The substrate scope was highly broad, including (iso)quinolines, substituted pyridines, pyrimidines, pyrazines, deazapurines, triazines, and benzimidazoles. Mechanistic ...[more]

PMID: 30155189

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