Visible-Light-Induced Nickel-Catalyzed Radical Cross-Couplings to Access α-Aryl-α-trifluoromethyl Alcohols

A photochemically induced nickel-catalyzed radical cross-coupling of phthalimido trifluoroethanol with aryl bromides to furnish alpha-aryl-alpha-trifluoromethyl alcohols is reported. This reaction proceeds via a photoinduced charge transfer of an electron donor- acceptor complex between Hantzsch ester and phthalimido trifluoroethanol, followed by 1,2-hydrogen atom transfer, to generate the alpha-hydroxytrifluoroethyl radical for the cross-coupling of aryl bromides. No exogenous photocatalysts or stoichiometric metal reductants are required in this mild and operationally simple protocol. Broad substrate compatibility and excellent functional group tolerance are observed.

Automated summary

A photochemically induced, nickel-catalyzed radical cross-coupling reaction has been developed for the synthesis of alpha-aryl-alpha-trifluoromethyl alcohols. This reaction utilizes a photoinduced charge transfer process between Hantzsch ester and phthalimido trifluoroethanol to generate a radical intermediate for the cross-coupling with aryl bromides. The protocol is mild and operationally simple, without the need for exogenous photocatalysts or stoichiometric metal reductants, and exhibits broad substrate compatibility and excellent functional group tolerance.