Copper-catalyzed one-pot synthesis of 1,3,4-oxadiazol-2(3H)-ones using DMF as the carbonyl source

A series of diaryl 1,3,4-oxadiazol-2(3H)-ones were prepared in moderate to good 34-72% yields by an efficient copper-catalyzed one-pot reaction of aryl hydrazides, arylboronic acids and DMF as the carbonyl source. A proposed mechanism for this reaction involves ligand exchange and transmetalation of a copper catalyst with aryl hydrazides and arylboric acids, followed by reductive elimination and intramolecular cyclization. Compared to previous work, the stable and readily available substrates enhance the practicality of this strategy, which also features a short reaction time, relatively low reaction temperature, and improved safety. Furthermore, this protocol features high functional group tolerance and reaction scalability.