Visible-Light-Induced Amination of Pyridylphosphonium Salts: Synthesis of Heteroarylamines via Radical–Radical Coupling

The development of operationally simple and efficient synthetic methodologies for constructing heteroarylamines is highly valuable in modern synthetic chemistry. Herein, we describe a visible-light-induced, mild, oxidant- and reductant-free radical-radical coupling between pyridylphosphonium salts and arylamines for their synthesis. This protocol exhibits excellent regioselectivity, broad substrate scope, and good functional group tolerance, enabling the late-stage functionalization of complex drug molecules and providing a sustainable pathway to valuable aromatic amines. Mechanistic studies indicate that DABCO acts as a key mediator, facilitating two sequential single-electron transfer (SET) and deprotonation processes.