AgNO3 as nitrogen source for rhodium(iii)-catalyzed synthesis of 2-aryl-2H-benzotriazoles from azobenzenes

Abstract

A new approach has been established for Rh(III)-catalyzed direct aza oxidative cyclization of non-prefunctionalized azobenzenes to provide 2-aryl-2H-benzotriazoles in good yields, in which AgNO₃ instead of conventional azide reagents for the first time functions as the nitrogen source for the nitrogenation reaction. Preliminary mechanistic studies suggest that the Rh(III)-catalyst could account for the nitration reaction, and subsequently cationic silver species might both play a vital role in the fission of the nitrogen–oxygen bonds in nitro groups and promote aza oxidative cyclization.