Green and controllable synthesis of symmetrical and unsymmetrical difluoromethylated diarylmethanes via a direct bisarylation strategy enabled by an HFIP–B(C6F5)3 adduct

Abstract

A metal-free B(C₆F₅)₃ and HFIP synergistically catalyzed bisarylation reaction between difluoroacetaldehyde ethyl hemiacetal and anilines was developed to efficiently synthesize symmetrical and unsymmetrical difluoromethylated diarylmethanes without using stoichiometric activating agents or in concentrated strong acid media. This efficient, scalable and operationally simple protocol displays high atom economy and broad substrate tolerance, allowing quick access to diverse symmetrical and unsymmetrical difluoromethylated diarylmethane products under mild conditions. Furthermore, the recyclability and reusability of the HFIP solvent make the reaction environmentally friendly.