Novel Pyridine-Catalyzed Reactionof Dimethyl Acetylenedicarboxylate with Aldehydes and<i>N</i>-Tosylimines: Efficient Synthesis of2-Benzoylfumarates and 1-Azadienes

Abstract

A novel reaction of 1,4-dipolar intermediate 3,generated from pyridine and dimethyl acetylenedicarboxylate, witharomatic aldehydes, resulted in the facile synthesis of 2-benzoylfumaratesvia the elimination of pyridine, whereas with N-tosyliminesas dipolarophiles the reaction afforded highly substituted 1-azadienes.The reaction of pyridine and dimethyl acetylenedicarboxylate withN-substituted isatins, resulted in a novel three component condensation,affording spiropyrido[2,1-b][1,3]oxazinoderivatives in high yields via 1,4-dipolar cycloaddition.