The reaction of di-tert-butyl malonate (I) with ethyl 2-bromoacetate (II) by means of NaH in THF gives di-tert-butyl 2-(ethoxycarbonylmethyl)malonate (III), which is condensed with trans-4-methylcyclohexylcarbonyl chloride (IV) by means of NaH in THF, and without isolation is treated with p-toluenesulfonic acid in refluxing toluene to afford trans-4-(4-methylcyclohexyl)-4-oxobutyric acid ethyl ester (V). Finally, this compound is hydrolyzed with aqueous NaOH.