CN1CCOCC1.[O:8]=[C:9]1[CH2:13][CH2:12][CH2:11][N:10]1[CH2:14][CH2:15][C:16]([OH:18])=O.[CH:19]1([Mg]Br)[CH2:23][CH2:22][CH2:21][CH2:20]1>C1COCC1.[Cu](I)I>[CH:19]1([C:16](=[O:18])[CH2:15][CH2:14][N:10]2[CH2:11][CH2:12][CH2:13][C:9]2=[O:8])[CH2:23][CH2:22][CH2:21][CH2:20]12-Chloro-4-6-dimethoxy-1,3,5-triazine (2.68 g, 15.2 mmol) and N-methylmorpholine (4.2 mL, 38.1 mmol) were added to a solution of 3-(2-Oxo-pyrrolidin-1-yl)-propionic acid (2 g, 12.7 mmol, from Step 1) in THF (35 mL). After 1 h the reaction mixture was filtered through a glass frit to remove a white precipitate. The filtrate was treated with copper iodide (2.4 g, 12.7 mmol), cooled to 0° C. and then cyclopentyl magnesium bromide (6.35 mL, 12.7 mmol, 2M in ether) was added. After 4 h the resulting black mixture was quenched with saturated NH4Cl and extracted with CH2Cl2. The organic layers were washed with 1 N HCl, saturated NaHCO3, brine, dried over Na2SO4 and concentrated. The residue was purifed by silica gel chromatography (75% EtOAc in hexanes then 5% MeOH in CH2Cl2) to give the title compound as a yellow oil. (0.4 g, 15% yield).
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