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.