Photoinduced radical alkylation of aldehydes with potassium alkyltrifluoroborates

Abstract

Radical addition to the carbonyl group has attracted long-standing interest in synthetic chemistry as it represents an orthogonal approach to classic electrophilic carbonyl reactivity. Herein we describe a protocol for radical alkylation of aldehydes with commercially available and shelf-stable potassium alkyltrifluoroborates. The formation of a complex between the aldehyde and difluoroalkylborane generated from the trifluoroborate and Lewis acid is believed to be a key factor responsible for the reaction efficiency. The process proceeds under visible light irradiation and does not require the use of a photocatalyst.