Organobismuth Compounds as Aryl Radical Precursors via Light-Driven Single-Electron Transfer
Nicholas D. Chiappini, Eric P. Geunes, Ethan T. Bodak, Robert R. Knowles
Abstract
A light-driven method for the generation of aryl radicals from triarylbismuth(III) and (V) reagents is described. Aryl radical generation is proposed to occur through the ligand-assisted mesolytic cleavage of an organobismuth(IV) intermediate generated from either oxidation of Bi III or reduction of Bi V . This mode of aryl radical generation is demonstrated to be compatible with a range of bimolecular radical arylations, including hydroarylation of electron-deficient olefins and arylation of diboronates, disulfides, sulfonyl cyanides, phosphites, and isocyanides. The intermediacy of an aryl radical is supported by radical trapping and radical clock experiments, and Bi IV –aryl mesolysis is supported computationally.