Electrophotocatalysis Versus Indirect Electrolysis: Electrochemical Selenocyclization of 3‐Aza‐1,5‐dienes Facilitated by Energy Transfer, Direct Photolysis or N‐Hydroxyphthalimide

Three hybrid electrochemical protocols, which involve the energy transfer, direct photolysis and N‐hydroxyphthalimide catalyst, respectively, are presented for the selenylation/cyclization of the fragile substrates of 3‐aza‐1,5‐dienes with diorganyl diselenides to afford 3‐selenomethyl‐4‐pyrrolin‐2‐ones. The two electrophotocatalytic reactions and the indirect electrolysis one are both regioselective and external‐oxidant‐ and transition‐metal‐free, and are associated with a broad substrate scope and high Se‐economy, and all three methods are amenable to gram‐scale syntheses, late‐stage functionalizations, sunlight‐induced experiments and all‐solar‐driven syntheses. Two new archetypes of electrophotocatalysis, including the first example of energy‐transfer‐involved photo/electro dual catalysis and the direct photolysis‐involved one, as well as a NHPI‐catalyzed electrochemical selenocyclization, are presented. These catalytic platforms enable direct syntheses of seleno 4‐pyrrolin‐2‐ones from 1,5‐dienes with broad substrate scopes in a mild, clean, Se‐economic, regioselective and oxidant‐ and metal‐free manner.