3,5-Dimethylcyclohex-2-en-1-one → 3-Benzyl-3,5-dimethylcyclohexanone

関与物質

反応手順

To a cooled (−20° C.) 1M benzylmagnesium bromide solution in diethyl ether (50 ml) under argon was added CuCl (0.52 g, 5.3 mmol) and the mixture was stirred for 5 min. Then a solution of 3,5-dimethyl-2-cyclohexen-1-one (12) (4.4 g, 35.1 mmol) in diethyl ether (15 ml) was added dropwise keeping the temperature below −10° C. The mixture was stirred for 2 h and quenched with 10% aqueous acetic acid (40 ml). The organic layer was separated, washed with water, saturated aqueous NaHCO3 and saturated aqueous NaCl, and dried over MgSO4. Filtration and concentration in vacuo afforded oily residue what was separated by flash chromatography on silica gel (light petroleum ether-ethyl acetate, 10:1). Cyclohexanone 13 (4.0 g, 53%) was obtained as a colorless oil.

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