Cobalt(II) chloride catalysed condensation of acetoacetate with enolisable aldehydes

Abstract

Enolisable aldehydes and methyl acetoacetate react in the presence of cobalt(II) chloride (catalytic) to give the corresponding α,β-unsaturated carbonyl compound in excellent yields. Non enolisable aldehydes do not react under these conditions. A catalytic cycle for these reactions has been proposed by involving the intermediacy of a cobalt(III) enol complex of aldehyde.