Visible-Light-Induced Povarov-Type Reaction of N -Alkyl Anthranilium Salts with Alkenes

Abstract Although numerous photocatalytic protocols have been established for the synthesis of tetrahydroquinolines, the development of synthetic systems independent of sophisticated and costly photocatalysts remains highly desirable. Herein, a photocatalyst-free, visible-light-induced Povarov-type reaction of N-alkyl anthranilium salts with alkenes is developed for the efficient construction of ortho-acyl-substituted tetrahydroquinoline scaffolds. This transformation proceeds via direct visible-light excitation of N-alkyl anthranilium salts to generate key iminium cation intermediates, which further undergo Povarov-type cyclization with alkenes. The reaction features simple and mild conditions, no requirement for external photocatalysts, and broad substrate compatibility. Moreover, this method provides a convenient strategy for accessing valuable deuterated nitrogen heterocycles.