NHC and photoredox co-catalyzed 1,4-alkylcarbonylation of 1,3-enynes†

Abstract

A strategy to obtain 1,2-alkenyl ketone products by radical relay coupling is proposed. We report that the ketyl radical produced by the single electron reduction of acyl azolium mediated by NHCs is a good coupling partner of alkenyl radicals, and the imidazole ions generated in this process directly activate alkylboronic acids to form alkyl radicals. This transformation mode is carried out under mild conditions and shows an excellent range of substrate applications.