An improved preparation of methyl 3-oxo-1-cyclohexene-1-carboxylate (6) is reported in which cyclohexanecarboxylic acid is converted to methyl 1-bromocyclohexanecarboxylate by a variation of the Hell-Volhard-Zelinsky reaction and then the bromo eater is dehydrohalogenated with quinoline and the resultant unsaturated ester is oxidized at an allylic position with chromium trioxide in acetic acid and acetic anhydride to give 6. The ...