Visible-light-promoted S -trifluoromethylation of thiophenols with trifluoromethyl phenyl sulfone.

Trifluoromethyl phenyl sulfone is traditionally a nucleophilic trifluoromethylating agent. Herein, we report the first example of the use of trifluoromethyl phenyl sulfone as a trifluoromethyl radical precursor. Arylthiolate anions can form electron donor-acceptor (EDA) complexes with trifluoromethyl phenyl sulfone, which can undergo an intramolecular single electron transfer (SET) reaction under visible light irradiation, thus realizing the S -trifluoromethylation of thiophenols under photoredox catalyst-free conditions. Similar S -perfluoroethylation and S -perfluoro- iso -propylation of thiophenols are also achieved using the corresponding perfluoroalkyl phenyl sulfones.