Mechanistical insight into 'electrophilic' trifluoromethylation with S-(trifluoromethyl)dibenzothiophenium salts

Trifluoromethyl sulfonium salts are widely used for the introduction of a trifluoromethyl group through reaction with a wide range of nucleophiles. Nevertheless, the reaction mechanism is far from obvious and has been the subject of various literature discussions. In this Letter, we show, through trapping experiments with a radical probe that, at least in the case of nucleophiles such as enol silyl ethers, the reaction proceeds by SET.