[CH2:1]([O:8][C:9](=[O:16])[NH:10][C@@H:11]([CH3:15])[CH2:12][CH2:13][OH:14])[C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=1.[Si:17](Cl)([C:20]([CH3:23])([CH3:22])[CH3:21])(C)C.N1C=CN=C1>CN(C=O)C.CCOC(C)=O>[CH2:1]([O:8][C:9](=[O:16])[NH:10][C@@H:11]([CH3:15])[CH2:12][CH2:13][O:14][SiH2:17][C:20]([CH3:23])([CH3:22])[CH3:21])[C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=1(3-Hydroxy-1-(S)-methyl-propyl)-carbamic acid benzyl ester (8.02 g, 35.9 mmol) was taken up in DMF (75 mL). tert-Butyl-dimethylsilyl chloride (8.12 g, 53.9 mmol) was added to the solution followed by imidazole (4.15 g, 61.0 mmol). The reaction was stirred at rt and monitored by TLC. The reaction was determined to be complete at 1 h by TLC. The reaction was taken up in EtOAc (200 mL) and partitioned between 5% LiCl(aq) (200 mL). The aqueous was back extracted with EtOAc. The organics were combined and washed with 3×200 mL 5% LiCl(aq), and dried over Na2SO4. Solids were filtered and solvent removed under reduced pressure. [3-(tert-Butyl-silanoxy)-1-(S)-methyl-propyl]-carbamic acid benzyl ester (12.73 g, 100%) was isolated by silica gel chromatography as a white solid.
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