The Reductive Deacylation of the Knoevenagel Condensates by the Use of the Tetracarbonylhydridoferrate(0) Anion. A New Synthetic Route of Ketones from Aldehydes

Abstract

The Knoevenagel condensates prepared from 2,4-pentanedione with aldehydes were allowed to react with the tetracarbonylhydridoferrate(0) anion in ethanol to give reductively deacylated monoketones in high yields. However, the exclusive reduction of the α,β-unsaturated double bond of the same condensates was encountered when the reaction was carried out in such a solvent as tetrahydrofuran and acetone. The Knoevenagel condensates, derived from the reaction of ethyl acetoacetate and/or ethyl benzoylacetate with aldehydes, were simply reduced even in ethanol. The reaction mechanism is briefly discussed.