Visible light-promoted defluorinative alkylation/arylation of α-trifluoromethyl alkenes with thianthrenium salts†

Herein, an operationally simple and mild protocol for defluorinative alkylation and arylation between thianthrenium salts and α-trifluoromethyl alkene with visible light to afford gem-difluoroolefins has been developed. The main feature of this method is avoiding the use of a metal photocatalyst, and an organic photocatalyst is unnecessary for the arylation reaction. In addition, thianthrene can also be recycled and transformed to thianthrenium salts without affecting the efficiency of these reactions. The protocol demonstrates excellent tolerance of functional groups and viable functionalization of late-stage natural products and pharmaceutically relevant molecules.