[O:1]=[C:2]1[CH2:7][CH2:6][CH:5]([CH2:8][C:9]([O:11][CH2:12][C:13]2[CH:18]=[CH:17][CH:16]=[CH:15][CH:14]=2)=[O:10])[CH2:4][CH2:3]1.[BH4-].[Na+]>CO>[OH:1][C@@H:2]1[CH2:3][CH2:4][C@H:5]([CH2:8][C:9]([O:11][CH2:12][C:13]2[CH:14]=[CH:15][CH:16]=[CH:17][CH:18]=2)=[O:10])[CH2:6][CH2:7]1Benzyl 2-(4-oxocyclohexyl)acetate (5.0 g, 20.3 mmol) was dissolved in methanol (150 ml), NaBH4 (770 mg, 20.3 mmol) was added by portions to the solution at 0° C., and the mixture was stirred for 2 hr. The mixture was concentrated under reduced pressure, followed by separation with ethyl acetate and water. The organic layer was washed with saturated brine and was dried over anhydrous magnesium sulfate, and the filtrate was concentrated under reduced pressure. The residue was chromatographed on silica gel column (hexane:ethyl acetate=85:15) to give the title compound as an oil (900 mg, yield 18%).
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