2-Cyclohexen-1-one → 3-Benzylcyclohexanone

To a solution of benzylmagnesiumchloride in THF (1.31 M, 393 mmol, 300 mL) CuCl (1.9 g) was added and the mixture was cooled to 0° C. The mixture was stirred for 6 min., and a solution of cyclohex-2-enone (193 mmol, 18.9 g) in THF (75 mL) was added dropwise at 0° C. over a period of 1 h. The reaction mixture was warmed to RT overnight. After cooling again to 0° C., saturated aqueous NH4Cl (450 mL) was added and the layers were separated. The aqueous layer was extracted with EtOAc (2×500 mL). The combined org. layers were washed with saturated aqueous NH4Cl (500 mL) and dried over Na2SO4. After evaporation, the crude product was subjected to column chromatography (SiO2, EtOAc/Hept=1/19→1/9) to give two fractions of product 01-1. Fraction 1 (23.5 g, 125 mmol, 65%, yellow oil) was used in the next step.