A catalyst-free, environmentally friendly, and efficient electrochemical selenylation/cyclization of alkenes has been developed with moderate to excellent yields. This selenylated transformation proceeds smoothly and tolerates a wide range of synthetically useful groups to deliver diverse functionalized benzheterocycles, including iminoisobenzofuran, lactones, oxindoles, and quinolinones. Moreover, the present synthetic route could also be readily scaled up to gram quantity with convenient operation in an undivided cell.

A novel selenium‐electrocatalytic intramolecular cyclization of 2‐vinylanilides for synthesis of functionalized indoles and azaindoles has been developed. In contrast to the previous synthetic methods, this sustainable protocol enabled unparalleled broad substrates scope for viable indoles with highly functional and sensitive groups by employing recyclable selenium catalyst, under mild, metal‐ and external‐oxidant‐free conditions. The approach can be used to the late‐stage modification of complex bioactive molecular system, thereby setting the stage for versatile syntheses of decorated indoles with peptide labeling. A plausible catalytic pathway was proposed.