[F:1][CH:2]1[C:8](=[O:9])[CH2:7][CH2:6][CH2:5][N:4]([C:10]([O:12][C:13]([CH3:16])([CH3:15])[CH3:14])=[O:11])[CH2:3]1.[BH4-].[Na+]>CO>[F:1][CH:2]1[CH:8]([OH:9])[CH2:7][CH2:6][CH2:5][N:4]([C:10]([O:12][C:13]([CH3:16])([CH3:15])[CH3:14])=[O:11])[CH2:3]1To a solution of the product from Step B (0.300 g, 1.30 mmol) in MeOH (6 mL) at 0° C. was added NaBH4 (0.123 g, 3.24 mmol) in one portion, and the mixture was warmed to ambient temperature and stirred for 5.0 hours. The mixture was concentrated and the residue was taken up in EtOAc (20 mL) and a saturated aqueous NH4Cl solution (5 mL) and water (5 mL). The layers were mixed and separated and the aqueous phase extracted with EtOAc (2×10 mL). The combined organic extracts were washed with brine and dried over Na2SO4, then filtered and concentrated. The crude product was purified by column chromatography (12% to 60% EtOAc/hexanes gradient) to provide 0.130 g (43%) of the major isomer as a colorless oil that solidified overnight to a white solid.
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