DMSO as a Switchable Alkylating Agent in Heteroarene C−H Functionalization

Abstract Herein, we report a novel strategy for the activation of DMSO to act as a versatile alkylating agent in heteroarene C−H functionalization. This direct, simple, and mild switch between methylation/trideuteromethylation and methylthiomethylation of heteroarenes was achieved under reagent‐controlled photoredox catalysis conditions. The proposed mechanism is supported by both experimental and computational studies.