Amine-catalyzed synthesis of N2-sulfonyl 1,2,3-triazole in water and the tunable N2-H 1,2,3-triazole synthesis in DMSO via metal-free enamine annulation

The selective synthesis of N-2-sulfonyl and N-2-H1,2,3-triazoles via organocatalytic annulation of enaminone/enaminoester with sulfonyl azide has been realized. The unconventional selectivity providing N-2-sulfoyl 1,2,3-triazoles takes place in pure water, wherein the hydrogen bond effect between water and the intermediate resulting from enamine-azide corporation accounts for the novel reaction selectivity. On the other hand, the reactions conducted in DMSO specifically afford N-2-H 1,2,3-triazoles in the absence of such hydrogen bond effect. (C) 2021 Published by Elsevier B.V. on behalf of Chinese Chemical Society and Institute of Materia Medica, Chinese Academy of Medical Sciences.

Automated summary

Selective synthesis of N-2-sulfonyl and N-2-H1,2,3-triazoles was achieved through organocatalytic annulation of enaminone/enaminoester with sulfonyl azide. The unconventional selectivity for N-2-sulfonyl 1,2,3-triazoles occurred in pure water, where the hydrogen bond effect between water and the intermediate formed by enamine-azide corporation accounted for the novel reaction selectivity. In contrast, the reactions conducted in DMSO specifically yielded N-2-H 1,2,3-triazoles in the absence of such hydrogen bond effect.