C[O:2][C:3]([C@@H:5]1[CH2:9][O:8][C:7]([CH3:11])([CH3:10])[N:6]1[C:12](=[O:19])[CH2:13][CH2:14][CH2:15][CH2:16][CH2:17][CH3:18])=O.[BH4-].[Li+]>CCOCC>[CH3:11][C:7]1([CH3:10])[N:6]([C:12](=[O:19])[CH2:13][CH2:14][CH2:15][CH2:16][CH2:17][CH3:18])[C@H:5]([CH2:3][OH:2])[CH2:9][O:8]1A solution of 8a (296 mg, 1.09 mmol) in dry ether (1 mL) is treated with lithium borohydride (2M solution in THF, 0.55 mL, 1.09 meq) under an argon atmosphere. The mixture is stirred for 3 h at reflux and 18 h at room temperature. The resulting mixture is diluted with ether and quenched with methanol. The volatiles are removed and the residue is taken up in EtOAc/H2O. Workup provides the crude alcohol which is purified by chromatography (2:1 hexane/EtOAc): NMR δ 0.88 (m, 3H), 1.30 (m, 6H), 1.54 (s, 3H), 1.62 (s, 3H), 2.35 (m, 2H), 3.30-4.40 (complex m, 6H); MS (HR-E1) m/z 243.1837 (M calcd. for C13H25NO3 243.1840); [α]D26 =-5±1 (CHCl3).
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