Visible Light-Promoted Phosphine-Catalyzed Difluoroalkylation of Arenes and Heterocycles

A visible light-promoted difluoroalkylation reaction of arenes or heterocycles, using triaryl phosphine as the catalyst and difluoroalkyl iodide as the alkylating agent, is presented. The strategy is highlighted by photocatalyst-free, mild reaction conditions and a broad substrate scope. Mechanistic experiments indicate that this reaction involves a radical-chain process that is initiated by an electron donor-acceptor complex formed from difluoroalkyl iodide and phosphine.