Visible-Light Copper Catalysis for the Synthesis of α-Alkyl-Acetophenones by the Radical-Type Ring Opening of Sulfonium Salts and Oxidative Alkylation of Alkenes.

Direct difunctionalization of simple alkenes has been treated as a powerful synthetic strategy for the construction of highly functionalized skeletons. In this study, direct oxidative coupling of sulfonium salts with alkenes was achieved under mild conditions by a blue-light-driven photoredox process using a copper complex as a photosensitizer. This protocol allows regioselective synthesis of aryl/alkyl ketones from simple sulfonium salts and aromatic alkenes via selective C-S bond cleavage of sulfonium salts and oxidative alkylation of aromatic alkenes using dimethyl sulfoxide (DMSO) as a mild oxidant.