Visible‐Light‐Promoted Radical Cyclization and N−N Bond Cleavage Relay of N‐Aminopyridinium Ylides for Access to 2,3‐Difunctionalized Indoles

Abstract Reported herein is a photocatalytic platform for the vicinal aminopyridylation of indoles. The accurate difunctionalization reaction undergoes a tandem process involving a radical‐mediated 1,3‐dipolar cycloaddtion which generated from the single‐electron oxidation of N ‐aminopyridinium ylides, a cleavage of the N−N bond as well as an oxidation of indoline ring. The electrophilic pyridyl and nucleophilic amino groups can be installed simultaneously into a wide range of indoles under mild and metal‐free conditions. Moreover, the protocol shows high levels of step and atom economy. magnified image