Visible Light-Driven Chlorodifluoromethylation of Unactivated Alkenes

A visible-light-driven regioselective chlorodifluoromethylation of unactivated alkenes has been developed. In this process, readily available difluoroacetic acid serves as a difluoromethyl radical precursor and, upon activation with (diacetoxyiodo)benzene under visible-light irradiation, generates the CF2H radical species. Subsequent addition to terminal, di-, or trisubstituted alkenes, followed by trapping with N-chlorosuccinimide, furnishes the chlorodifluoromethylated products in good yields. Notably, the method has been used for the chlorodifluoromethylation of natural products and functional molecules, and the resulting C–Cl bond can undergo diverse derivatizations including replacement with heteroatoms.