Photoredox‐Induced Deaminative Radical‐Cationic Three‐Component Couplings with N‐Alkylpyridinium Salts and Alkenes.

N‐Benzyl‐ and N‐2°‐alkylpyridinium salts were engaged in visible‐light‐driven, photoredox‐induced radical‐cationic three‐component couplings with N‐methylmaleimide and acrylonitrile as radical acceptors, in combination with 1,1‐diarylethylenes as donor alkenes. These multicomponent coupling reactions could be achieved under mild conditions, with high efficiency, and to furnish diverse 3,4‐disubstituted pyrrolidin‐2,5‐dione products with high stereoselectivity. In addition, 2,3‐diaryl‐1,3‐butadienes could be utilized as alternative donor alkene components, to furnish diastereomerically pure 1,2,3‐trisubstituted 1,3‐butadienes as the coupling products. [ABSTRACT FROM AUTHOR]