The synthesis of 1,4-diketones via fluoride-catalysed Michael addition and supported-permanganate-promoted nef transformation

Abstract

A versatile synthetic route for the preparation of 1,4-diketones from simple starting materials is described and applied to the preparation of a wide range of diketones. The two most important steps in the reaction are the fluoride ion-catalysed Michael addition of a nitroalkane to a vinyl ketone and the subsequent transformation of the nitro ketone to the diketone using supported permanganate as the oxidant. The interaction of F^– with nitroethane has been studied and a number of sources of F^– have been tested in the Michael addition reaction. Potassium fluoride supported on alumina and potassium permanganate supported on silica gel are remarkably efficient reagents for the Michael addition and Nef transformation stages, respectively, although it is important to determine the best reagent loadings and drying conditions for maximum reaction efficiency to be achieved.