Selective diarylmethane formation in the reaction of iron(III) perchlorate with alkylbenzenes

Abstract

Treatment of alkylbenzenes with iron(III) perchlorate in acetic acid affords diarylmethanes selectively in good yields; the formation of biaryls reported in previous studies with iron(III) chloride was not observed. Reactions with other iron(III) salts in the presence of perchloric acid proceed similarly. The reaction is interpreted in terms of formation of a benzylic cation, followed by its electrophilic attack on another alkylbenzene molecule.