Electrochemical Trifluoromethylchlorosulfonylation of Alkenes via Copper-Mediated SO₂Cl Radical Transfer

This report describes an electrosynthetic method for vicinal trifluoromethylchlorosulfonylation of alkenes using the readily available copper salt [Cu(MeCN)₄]PF₆ and triethylamine, without the need for elaborate ligands. This protocol enables efficient and selective addition of CF₃ and SO₂Cl groups across a wide range of unactivated alkenes with broad functional group tolerance, including pyrrole, furan, thiophene, thioethyl, and silyl substituents. The sulfonyl chloride products can be readily transformed into sulfonamides, sulfonates, sulfonyl fluorides, and thiosulfonates. Mechanistic studies provide evidence in support of an electrochemically driven, Cu-mediated SO₂Cl radical transfer mechanism.