Asymmetric Diels–Alder reaction between furans and propiolates

Abstract

Abstract We report the first asymmetric Diels–Alder reaction between furan and propiolates. Propiolate, a dienophile, was equipped with an Evans’ auxiliary and a sulfonyl group to control and facilitate diastereoselective cycloaddition. Treatment with furan as a diene and aluminium Lewis acid afforded a 7-oxabicyclo[2.2.1]heptadiene skeleton diastereoselectively. The origin of diastereoselectivity can be explained by chelation of aluminium center to carbonyl groups and oxygen of furan. Friedel–Crafts-type products were obtained when pyrrole was used as diene.