Thermal, three-carbon + two-atom cycloaddition of cyclopropenone ketals with carbon-heteroatom double bonds: Butenolide, furan, and γ-keto ester preparation.

Abstract

A preliminary study of the thermal reaction of cyclopropenone ketals with carbon-heteroatom double bonds is detailed. The reaction with aldehyde and keto carbonyls provide butenolide ortho esters, the product of a formal three-carbon + two-atom cycloaddition of the cyclopropenone ketal across the carbon-oxygen double bond.