Copper-MediatedDirect Trifluoromethylation of TrichloromethylAlkanes

CF₃CCl₂-containing compounds are of significant synthetic value but are typically synthesized from environmentally harmful hydrochlorofluorocarbons (CFCs). Herein, we report the use of a well-defined Cu(I) complex, [(bpy)Cu(CF₃)], as an efficient trifluoromethylating reagent for the direct trifluoromethylation of trichloroalkanes under mild conditions, affording CF₃CCl₂-containing products with excellent chemoselectivity. This protocol also enabled the gram-scale synthesis of cyhalothric acid ester, which is a key intermediate in the production of pyrethroid pesticides.