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

Herein, we developed a silane-promoted cycloaddition of thiobenzhydrazides with carbon dioxide leading to 1,3,4-thiadiazol-2(3)-ones. This procedure involves sequential -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.

Pyridine-catalyzed ring-opening reaction of cyclopropenone with bromomethyl carbonyl compounds toward furan-2(5)-ones.

We developed a pyridine-catalyzed annulation of diaryl cyclopropenone with bromomethyl carbonyl compounds leading to 5-carbonyl furan-2(5)-ones. Pyridinium, derived from the reaction of bromomethyl carbonyl and pyridine, triggered the reaction by the inter-molecular Michael addition to cyclopropenone. This procedure was sensitive neither to air nor moisture and proceeded at room temperature with broad substrate scopes and good functional group tolerance in moderate-to-good yields.