Ammonium Chloride → Ethyl 4-hydroxy-4-methylcyclohexane-1-carboxylate

To a solution of ethyl 4-oxocyclohexanecarboxylate (4.00 g, 23.5 mmol) in diethyl ether (80 mL) was added MeLi (37.6 mL, 1M in diethyl ether) at −60° C. under nitrogen atmosphere. The reaction mixture was stirred at −60° C. for 30 min. Saturated aqueous NH4Cl (50 mL) was added and the resulting mixture was extracted with EtOAc (100 mL×2). The combined organic layers were washed with brine (150 mL) and water (150 mL), dried over anhydrous sodium sulfate, and concentrated. The residue was purified by flash column chromatography on silica gel (petroleum ether/EtOAc=10:1) to afford ethyl 4-hydroxy-4-methylcyclohexanecarboxylate (1.8 g, 41% yield) as an oil.