[CH2:1]([O:8][C:9]([N:11]1[CH2:15][C@@H:14]([OH:16])[CH2:13][C:12]1=[O:17])=[O:10])[C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=1.[Si:18](Cl)([C:21]([CH3:24])([CH3:23])[CH3:22])([CH3:20])[CH3:19].N1C=CN=C1>CN(C)C=O>[CH2:1]([O:8][C:9]([N:11]1[CH2:15][C@@H:14]([O:16][Si:18]([C:21]([CH3:24])([CH3:23])[CH3:22])([CH3:20])[CH3:19])[CH2:13][C:12]1=[O:17])=[O:10])[C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=1A mixture of (4S)-N-benzyloxycarbonyl-4-hydroxy-2-pyrrolidone (116 g), t-butyldimethylsilyl chloride (81.4 g), imidazole (67.4 g) and dimethylformamide (350 ml) is stirred at room temperature for 17 hours, and the solvent is evaporated in vacuo. To the residue is added ethyl acetate, and the mixture is washed with water, dried and concentrated under reduced pressure. The residue is purified by silica gel column chromatography (eluent, n-hexane :ethyl acetate=4:1 to 2:1) to give (4S)-N-benzyloxycarbonyl-4-t-butyldimethylsilyloxy-2-pyrrolidone (160 g) as colorless needles.
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