Photoinduced cross-coupling of aryl halides enabled by n-tetrabutylphosphonium phthalate

Abstract

The generation and control of aryl radicals pose considerable challenges, such as highly negative reduction potentials of aryl halides and their amphiphilic character. Herein, we introduce the synergistic interplay of a three-component photoactive electron-transfer system that enables photoinduced cross-coupling of aryl halides using n-tetrabutylphosphonium phthalate as a one-electron-transfer mediator. Our method readily accommodates the formation of four different bond-forming reactions (C(sp²)–C/P/B/S). The present approach exhibits good functional group tolerance and biocompatibility with plasmids, DNase, and serum albumin, as well as great efficiency for late-stage incorporation into drug molecules, BODIPY dye, and natural compounds. Mechanistic investigations revealed the bifunctional property of n-tetrabutylphosphonium phthalate potentially through two-point non-covalent interaction to bring aryl halides and pyrrole derivatives within proximity for facilitated electron transfer.