Silane-promoted cycloaddition of thiobenzhydrazides with carbon dioxide toward 1,3,4-thiadiazol-2(3H)-ones.

Herein, we developed a silane-promoted cycloaddition of thiobenzhydrazides with carbon dioxide leading to 1,3,4-thiadiazol-2(3H)-ones. This procedure involves sequential N-silylation and fixation of carbon dioxide toward a hydrazine formyl intermediate, followed by intramolecular nucleophilic cyclization and aromatization. A series of functional groups are well-tolerated under this procedure. As such, it represents a facile and efficient pathway for utilizing carbon dioxide in the construction of value-added heterocyclic frameworks.