Further studies on the Stobbé condensation with 2-methyl cyclohexanone

Abstract

2-Methyl cyclohexanone is condensed with dimethyl succinate in the presence of potassium tertiary butoxide giving a solid mixture of isomers of the corresponding alkylidene and alkenyl half-esters. On alkaline hydrolysis this gives β-carboxy-β-(2-methyl cyclohex-1-enyl)propionic acid. The keto-ester obtained by cyclization of the half-ester yielded the corresponding unsaturated ketone after acid hydrolysis and decarboxylation. Reduction of the keto-ester affords the corresponding α,β-unsaturated ester. Both the unsaturated ketone and ester are easily hydrogenated in the presence of platinum oxide to the corresponding saturated ketone and ester.