Dual Copper/PhotoredoxCatalysis for Radical-Mediated Arylation and Alkylation of Sulfenamides

Radical-based pathways provide an attractive approach for constructing C(sp²/sp³)–S bonds from various substrates. Herein we report two strategies that can be used for aryl radical sulfilimination of aryl sulfonium salts and aryl radical–mediated cross-coupling reactions between alkyl iodides and sulfenamides, both via synergetic photoredox and copper catalysis. These mild, operationally simple reactions have a broad substrate scope and potential utility for late-stage functionalization of natural products and drug molecules. In addition, both sulfilimination reactions can be carried out on a gram scale under continuous-flow conditions. Mechanistic studies indicate that rapid abstraction of the iodine atom from the alkyl iodide by sterically hindered, electron-rich aryl radicals and tuning of the electronic properties of the copper catalyst by varying the ligand contribute to the chemoselectivity for alkylation.