I₂-Catalyzed Oxidative Coupling Reactions of Hydrazones and Amines and the Application in the Synthesis of 1,3,5-Trisubstituted 1,2,4-Triazoles

A general and expeditious approach for the metal-free mediated synthesis of 1,3,5-trisubstituted 1,2,4-triazoles from hydrazones and aliphatic amines has been achieved under aerobic oxidative conditions. The reaction proceeds through a cascade C-H functionalization, double C-N bonds formation, and oxidative aromatization sequence.