A general and convenient synthesis of β-ketols and α, β-alkenones has been achieved by a Knoevenagel condensation of a β-ketoacid with an aldehyde in aqueous medium. Saponification of a β-ketoester by an aqueous KOH 10% solution gives the potassium salt of the β-ketoacid, which is condensed in situ with an aldehyde at pH 7.8-8.0, at 60° C for 5-6 h. The intermediate β-ketocarboxylate is smoothly decarboxylated in the reaction medium, ...
