Synthesis of Furo[2,3‑e][1,4]diazepin-3-one Derivatives through Tandem Cyclization/[4 + 3] Annulation Reactions

A variety of furo­[2,3-e]­[1,4]­diazepin-3-one derivatives were facilely synthesized through one-pot tandem cyclization/[4 + 3] annulation reactions between enynamides and α-bromohydroxamates. The reactions proceeded efficiently at room temperature, and various functional groups were well tolerated. The obtained furo­[2,3-e]­[1,4]­diazepin-3­(2H)-ones containing a 7-membered dinitrogen-fused ring might be of biological and medicinal value. The products could be further derived using convenient procedures.