[CH2:1]([O:8][C:9](=[O:24])[NH:10][C@H:11]([CH:18]1[CH2:23][CH2:22][CH2:21][CH2:20][CH2:19]1)[C:12](=[O:17])N(OC)C)[C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=1.[H-].[H-].[H-].[H-].[Li+].[Al+3]>C1COCC1>[CH2:1]([O:8][C:9](=[O:24])[NH:10][C@H:11]([CH:18]1[CH2:19][CH2:20][CH2:21][CH2:22][CH2:23]1)[CH:12]=[O:17])[C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=1To a solution of [(R)-Cyclohexyl-(methoxy-methyl-carbamoyl)-methyl]-carbamic acid benzyl ester (27 g, 82 mmol) in THF (400 mL) at −20° C. was slowly added LiAlH4 (4.06 g, 106 mmol, 1.3 equiv). LiAlH4 was freshly ground from pellet purchased from Aldrich. During addition, the internal temperature was carefully monitored and did not rise above 0° C. After addition the mixture was stirred at 0° C. and the reaction was monitored by TLC and LCMS. After 1 hour, the reaction solution was cooled at −10° C. and quenched by slow addition of sat. aq. KHSO4 solution until pH=5. The mixture was partitioned between water and EtOAc. The phases were separated and the organic layer was concentrated. The residue was dissolved in EtOAc and the solution was washed with water, brine, dried over Na2SO4 and concentrated to give product ((R)-1-Cyclohexyl-2-oxo-ethyl)-carbamic acid benzyl ester 22 g (99%). The material was continued to next step with no further purification.
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