[CH3:1][O:2][C:3](=[O:9])[CH2:4][C:5](=[O:8])[CH2:6][CH3:7].[H-].[Na+].Br[CH2:13][C:14]1[CH:19]=[CH:18][C:17]([F:20])=[CH:16][CH:15]=1>CN(C)C=O.O1CCCC1>[CH3:1][O:2][C:3](=[O:9])[CH:4]([CH2:13][C:14]1[CH:19]=[CH:18][C:17]([F:20])=[CH:16][CH:15]=1)[C:5](=[O:8])[CH2:6][CH3:7]3-Oxopentanoic acid methyl ester (7.5 g) was added to a stirred suspension of sodium hydride (60% in oil, 4.6 g) in N,N-dimethylformamide (20 mL) and tetrahydrofuran (80 mL) at 0° C. and the resulting mixture stirred at 0° C. for 30 minutes. A solution of 1-bromomethyl-4-fluorobenzene (7.0 mL) in tetrahydrofuran was added and the resulting mixture warmed to room temperature and then stirred at this temperature for 17 hours. The mixture was partitioned between ethyl acetate and water and the aqueous phase extracted with ethyl acetate. The combined organic phases were dried over sodium sulfate and the solvent removed under reduced pressure. The residue was purified by column chromatography on silica gel, eluting with a mixture of cyclohexane and ethyl acetate (19:1 by volume) to afford title compound, 1.0 g.
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