Intermediate 1 (850 mg) and tetrakis(triphenylphosphine)-palladium (0) (250 mg) are dissolved in tetrahydrofuran (16 ml), and thereto is added a 0.5 M tetrahydrofuran solution (20 ml) of cyclohexylzinc bromide under argon atmosphere at room temperature, and the mixture is stirred for 18 hours. A saturated aqueous ammonium chloride solution is added to the reaction solution, and the mixture is extracted with ethyl acetate. The organic layer is dried over sodium sulfate, and the solvent is evaporated under reduced pressure. The residue is purified by silica gel column chromatography (eluent: gradient from 0% to 100% hexane/ethyl acetate) to give the desired compound (120 mg).
