Paired Electrolysis Enabled Trifluoromethylheteroaromatization of Alkenes and Alkyne with Trifluoromethyl Thianthrenium Triflate (TT-CF 3 + OTf - ) as a Bifunctional Reagent.

We report a strategic exploitation of trifluoromethyl thianthrenium triflate (TT-CF 3 + OTf - ) as both electromediator and CF 3 radical precursors for paired electrolysis. Enabled by this strategy, the three-component trifluoromethylheteroaromatization of alkenes and alkynes was realized. The superiority of TT-CF 3 + OTf - to other electrophilic CF 3 reagents is attributed to the cathodic generation of thianthrene (TT) as a mediator, which shifts the heterogeneous oxidation of interest to a homogeneous one.