TBAI or KI‐Promoted Oxidative Coupling of Enamines and N‐Tosylhydrazine: An Unconventional Method toward 1,5‐ and 1,4,5‐Substituted 1,2,3‐Triazoles

A novel method for the synthesis of 1,5‐ and 1,4,5‐substituted 1,2,3‐triazoles has been reported. This approach is promoted by iodine‐TBHP oxidation system using enamines and N‐tosylhydrazine as materials, which avoid the dependence of traditional methods on azides and transition metals. Through this approach, various 1,5‐ and 1,4,5‐substituted 1,2,3‐triazoles were delivered in moderate to high yields. The mechanistic study indicated that an amino exchange would be involved in the reaction process. Moreover, the product methyl 1‐(2‐methoxyphenyl)‐4‐methyl‐1H‐1,2,3‐triazole‐5‐carboxylate is a useful precursor to anti‐influenza A agent, and further application research was conducted.