Transition-metal free direct difluoromethylthiolation of electron-rich aromatics with difluoromethanesulfonyl chloride

Abstract

A new method for phosphine-mediated difluoromethylthiolation of indole derivatives and other electron-rich aromatics including pyrroles, pyrazolones, indolizine, and 1,3,5-trimethoxybenzene was developed using difluoromethanesulfonyl chloride. The additive n-Bu₄NI was demonstrated to facilitate this reaction by generating iodine in situ, which could promote this transformation. The use of a transition-metal-free protocol, readily available reagents, and mild reaction conditions makes this protocol more practical than traditional methods.