Photoinduced Synthesis of ( Z )‐ β ‐Sulfonamido Enamines via an Electron Donor–Acceptor Complex With N ‐(Sulfon)amido Pyridinium Salts

A novel, visible‐light‐driven, transition‐metal, and photocatalyst‐free methodology for the C(sp 2 )–H amination of enamines has been developed, enabling the regio‐ and stereoselective synthesis of ( Z )‐ β ‐sulfonamido enamines from readily accessible N ‐aminopyridinium salts. This new protocol provides straightforward access to a broad range of ( Z )‐ β ‐sulfonamido enamines (32 examples, 31%–78% yields) and proceeds via an electron donor–acceptor complex‐initiated radical pathway, as supported by mechanistic studies. Its synthetic robustness was further demonstrated through a gram‐scale reaction, one‐pot three‐component processes, and successful application to natural sunlight‐driven transformations. The utility of this method in pharmaceutical chemistry was highlighted by the late‐stage functionalization of amino‐containing drug derivatives. Overall, this operationally simple and mild strategy offers an efficient new platform for constructing functionalized enamine derivatives of synthetic significance.