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.