Conversion of Simple Alkenes into 1H-1,2,3-Triazolium Salts by Oxidative Cycloaddition and Subsequent Dehydrogenation

A new method for preparing 1H-1,2,3-triazolium salts from triazenes and simple alkenes has been developed. The oxidative cycloaddition of triazenes and alkenes produces 4,5-dihydro-1H-1,2,3-triazolium salts, which undergo dehydrogenation under very mild conditions (using potassium bicarbonate in air at room temperature) to provide 1H-1,2,3-triazolium salts. This method demonstrates high functional tolerability and enables the synthesis of a triazolium-based diol, which can serve as a cationic diol monomer for cationic polymer synthesis.