Chemo‑, Regio‑, and Stereoselective Trifluoromethylation of Styrenes via Visible Light-Driven Single-Electron Transfer (SET) and Triplet–Triplet Energy Transfer (TTET) Processes

A process for tunable and chemo-, regio-, and stereoselective photocatalytic trifluoromethylation of styrenes was developed. Thermodynamically stable <i>E</i>-trifluoromethylated alkenes were prepared using Togni’s reagent in the presence of Ru­(bpy)₃Cl₂·6H₂O under visible light irradiation, whereas less thermodynamically stable <i>Z</i>-trifluoromethylated alkenes were obtained by employing Umemoto’s reagent and photocatalyst Ir­(ppy)<sub>3