[BH4-].[Na+].[CH2:3]([O:7][CH:8]([O:10][C@H:11]([CH3:19])[C:12](OCC(C)C)=[O:13])[CH3:9])[CH:4]([CH3:6])[CH3:5].CO.O>C1CCCCC1.C(OCC)(=O)C>[CH2:3]([O:7][CH:8]([O:10][C@H:11]([CH3:19])[CH2:12][OH:13])[CH3:9])[CH:4]([CH3:6])[CH3:5]
5.7 g of sodium borohydride was suspended at room temperature in a solution of 25.0 g of the isobutyl (R)-(+)-2-(1-isobutoxyethoxy)propionate (obtained in Reference Example 4) dissolved in 30 ml of cyclohexane. Thereto was dropwise added slowly 24 ml of methanol with stirring, so that the internal temperature of the reaction system could be kept at 40° C. After the completion of the dropwise addition, the mixture was stirred at room temperature for 5 hours. After the reaction, the reaction mixture was added 100 ml of water, followed by stirring for a while. Thereto was added 200 ml of ethyl acetate. The resulting organic layer was separated, washed with a saturated aqueous sodium chloride solution, and dried over anhydrous sodium sulfate. The resulting solution was subjected to vacuum distillation to remove the solvent. The resulting concentrate was subjected to distillation to obtain 17.3 g (yield: 98.0%) of an oily title compound (diastereomixture).
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