Conversion of simple alkenes into 1H-1,2,3-triazolium salts by oxidative cycloaddition and subsequent dehydrogenation

Abstract

A new method for the synthesis of 1H-1,2,3-triazolium salts from triazenes and simple alkenes has been developed. The oxidative [3+2] cycloaddition of triazenes with alkenes affords 4,5-dihydro-1H-1,2,3-triazolium salts, which undergo dehydrogenative aromatization under remarkably mild conditions (using potassium bicarbonate in air at room temperature) to provide 1H-1,2,3-triazolium salts. This method exhibits broad functional group tolerance and enables the synthesis of a triazolium-based diol, which serves as a cationic diol monomer for cationic polymer synthesis.