Crossed Acyloin Condensation of Aliphatic Aldehydes

Abstract

Crossed acyloins were efficiently prepared by the thiazolium-catalysed condensation of two different unhindered aldehydes, using one mol equivalent of one aldehyde with three mol equivalents of the other. Conversion into the corresponding nonsymmetrical 1,2-dioxime was achieved either by oxidation with bismuth(III) oxide or the Dess−Martin periodinane to give a 1,2-diketone that was then treated with hydroxylamine to give the oxime.