[Si:1]([O:8][CH2:9][C@@H:10]1[NH:14][C:13](=[O:15])[CH2:12][CH2:11]1)([C:4]([CH3:7])([CH3:6])[CH3:5])([CH3:3])[CH3:2].CC(C)([O-])C.[K+].Br[CH2:23][C:24]([O:26][CH3:27])=[O:25].O>O1CCCC1.CCCCCC.C(OCC)(=O)C>[Si:1]([O:8][CH2:9][C@H:10]1[CH2:11][CH2:12][C:13](=[O:15])[N:14]1[CH2:23][C:24]([O:26][CH3:27])=[O:25])([C:4]([CH3:7])([CH3:6])[CH3:5])([CH3:3])[CH3:2]To a solution of (5R)-5-({[tert-butyl(dimethyl)silyl]oxy}methyl)-2-pyrrolidinone (11.2 g) in tetrahydrofuran (97 mL) were potassium tert-butoxide (6.27 g) and methyl bromoacetate (8.11 g) at 0° C. and the solution was stirred for 2 Hours. To the reaction solution were added water, ethyl acetate and hexane and the reaction solution was separated. The aqueous layer was extracted with ethyl acetate. The combined organic layer was washed with water and brine, dried over anhydrous sodium sulfate and concentrated to give the title compound (14.3 g) having the following physical data.
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