[CH2:1]([O:8][CH2:9][C@@H:10]([C:19](N(OC)C)=[O:20])[NH:11][C:12]([O:14][C:15]([CH3:18])([CH3:17])[CH3:16])=[O:13])[C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=1.[H-].[H-].[H-].[H-].[Li+].[Al+3]>C(OCC)C>[CH2:1]([O:8][CH2:9][CH:10]([NH:11][C:12](=[O:13])[O:14][C:15]([CH3:17])([CH3:16])[CH3:18])[CH:19]=[O:20])[C:2]1[CH:3]=[CH:4][CH:5]=[CH:6][CH:7]=1A cold (10° C.) solution of O-benzyl-N1-methoxy-N1-methyl-N2-(tert-butoxycarbonyl)serinamide (6.27 g, 18.5 mmol) in diethyl ether (312 mL) was treated in portions with LAH (780 mg, 20.6 mmol). The reaction was stirred under inert atmosphere for 30 min and quenched at 0° C. by the addition of a solution of KHSO4 (16 g) in water (75 mL). The mixture was diluted with 1 M aqueous HCl (60 mL), and the organic layer was washed with brine, dried over MgSO4 and concentrated in vacuo to a yellow oil. Purification by silica gel chromatography (10% to 50% EtOAc/hexanes) afforded the title compound as a colorless oil. 1H NMR (500 MHz, CDCl3) δ 9.64 (s, 1H), 7.38-7.26 (m, 5H), 5.42 (d, J=5.0 Hz, 1H), 4.51 (dd, J=12.0, 19.5 Hz, 2H), 4.32 (d, J=4.01-3.99 (m, 1H), 3.73-3.70 (m, 1H), 1.46 (s, 9H). ES MS (M+1−100, for loss of BOC group)=180.1.
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