A NOVEL INVERSE TYPE DIELS-ALDER REACTION OF ETHYL (E)-3-(1, 3-BENZOTHIAZOL-2-YL)-3-CYANOPROPENOATE AS A HIGHLY REACTIVE 1-AZA-1, 3-BUTADIENE

Abstract

Diels-Alder reactions of ethyl (E)-3-(1, 3-benzothiazol-2-yl)-3-cyanopropenoate (2) as a 1-aza-1, 3-butadiene are described. The diene (2), bearing electron-withdrawing ester group, reacts with electron-rich dienophiles (3a-d) under extremely mild conditions to give corresponding cycloadducts (4a-d) in high yields with high regio- and endo-selectivities. Treatment of 2 with electron-donating allyl alcohols (5a, b) causes tandem transesterification and intramolecular cycloaddition to afford cis-fused polycyclic systems (6a, b) in one step.