Visible-Light-Promoted Nickel-Catalyzed Cross-Coupling of Alkyltitanium Alkoxides with Aryl and Alkenyl Halides

Abstract

Here, we report that alkyltitanium alkoxides generated in situ from Grignard reagents and Ti­(OiPr)4 undergo a photocatalyst-free nickel-catalyzed cross-coupling with organic halides upon irradiation with blue light. Mechanistic studies suggested that the reaction proceeds through radical intermediates formed by photochemical decomposition of the alkyltitanium reagents. Various aryl, heteroaryl, and vinyl halides were efficiently alkylated under the reported conditions, including those containing ester and amide groups.

Demystifying the recent photochemical and electrochemical strategies in installing the magic methyl group: a comprehensive overview

“…67). 141 Alkyltitanium alkoxides could be generated in situ from Grignard reagents and Ti (OiPr) 4 . Various aryl, heteroaryl, and vinyl halides were efficiently alkylated under the reported conditions, including the methylation of 2-bromonaphthene (MeMgBr, 94% yield and MeMgI, 98% yield).…”

Visible-Light-Promoted Reduction of Epoxides, Hydroxysulfonates, and Halohydrines with Alkyltitanium Alkoxides

“…In our group, a light-promoted cross-coupling of alkyltitanium alkoxides with organic halides was recently developed. 16 The reaction proceeded through the light induced Ti−C bond homolysis, and then both alkyl radical and Ti III species were engaged in the nickel catalytic cycle.…”

“…While chlorine radical abstracted H atom from the substrate, Ti III species were necessary in the subsequent Giese addition stage for reduction of the radical center to an anion. In our group, a light-promoted cross-coupling of alkyltitanium alkoxides with organic halides was recently developed . The reaction proceeded through the light induced Ti–C bond homolysis, and then both alkyl radical and Ti III species were engaged in the nickel catalytic cycle.…”

Visible-Light-Promoted Reduction of Epoxides, Hydroxysulfonates and Halohydrines with Alkyltitanium Alkoxides

“…In our group, a light-promoted crosscoupling of alkyltitanium alkoxides with organic halides was recently developed. 16 The reaction proceeded through the light induced Ti-C bond homolysis and then both alkyl radical and Ti III species were engaged in the nickel catalytic cycle.…”