[OH:1][CH2:2][CH2:3][C@@H:4]1[O:8][C:7]([CH3:10])([CH3:9])[O:6][C:5]1=[O:11].N1C=CN=C1.[C:17]([Si:21]([CH3:24])([CH3:23])Cl)([CH3:20])([CH3:19])[CH3:18].O>CN(C)C=O>[C:17]([Si:21]([CH3:24])([CH3:23])[O:1][CH2:2][CH2:3][C@@H:4]1[O:8][C:7]([CH3:9])([CH3:10])[O:6][C:5]1=[O:11])([CH3:20])([CH3:19])[CH3:18]Step C A mixture of (S)-5-(2-hydroxy-ethyl)-2,2-dimethyl-[1,3]dioxolan-4-one (6.8 g, 42 mmol) and imidazole (7.5 g, 107 mmol) in dimethylformamide (40 mL) was added tert-butyldimethylchlorosilane (7 g, 45 mmol). The reaction mixture was stirred at room temperature for 18 h. Water was added. The organic layer was separated, the aqueous layer was then extracted with ethyl acetate twice. The combined organic layers were washed with brine, dried over MgSO4, concentrated to give (S)-5-[2-(tert-butyl-dimethyl-silanyloxy)-ethyl]-2,2-dimethyl-[1,3]dioxolan-4-one as a colorless oil (8.6 g, 74%).
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