TfOH/HFIP Cluster-Promoted Direct C–F Bond Activation of Trifluoromethyl Arenes/Alkanes

A direct C-F bond activation for trifluoromethyl compounds promoted by the TfOH/HFIP cluster is developed, allowing the conversion of various trifluoromethyl arenes and trifluoromethylalkanes to diverse carboxylic acids and their derivatives. This method is distinguished by its broad substrate scope, good functional group tolerance, and exclusive regioselectivity. The utility of this reaction is further showcased on a gram scale and in the synthesis of the ultraviolet (UV) absorber and fenofibrate. Control experiments confirmed the crucial role of the TfOH/HFIP cluster in achieving this efficient conversion.