Feist‐Bénary Reaction

Abstract

The synthesis of furan derivatives by treatment of an α‐halo ketone and β‐dicarbonyl compound with a base is known as the Feist‐Bénary condensation. The bases used are normally ammonia and pyridine, however, it was found advantageous to use aqueous pyridine to effect this reaction instead of ammonia, because the production of pyrrole derivative is obviated and the yield of the furan derivative is increased. The intermediate dihydrofuran has been isolated with good diastereoselectivity under mild conditions. This reaction has been extended to prepare furan from α,β‐dichloroethyl ether and β‐ketoester in aqueous pyridine solution to reduce the formation of pyrrole.