Visible‐Light‐Mediated Cycloaddition of Azobenzenes and Nonstabilized Azomethine Ylides to Access 1,2,4‐Triazolidines

Abstract

AbstractA visible‐light‐mediated cycloaddition of azobenzenes and nonstabilized azomethine ylides has been developed to access 1,2,4‐triazolidines. With readily available organic dye rose bengal as a photocatalyst and alkyl tertiary amines as precursors for azomethine ylides, the reaction proceeded smoothly under visible light irradiation at room temperature, affording various 4‐alkyl‐1,2‐diaryl‐1,2,4‐triazolidines with yields of up to 96%. Preliminarily mechanistic studies suggest that the nonstabilized azomethine ylides are formed in situ through photoredox catalysis.