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.