C([Li])CCC.Br[C:7]1[CH:12]=[C:11]([F:13])[C:10]([Br:14])=[CH:9][C:8]=1[F:15].CN([CH:19]=[O:20])C.C(OCC)(=O)C>CCOCC.C1COCC1.CCCCCC>[Br:14][C:10]1[C:11]([F:13])=[CH:12][C:7]([CH:19]=[O:20])=[C:8]([F:15])[CH:9]=1
n-Butyl lithium (3.6 ml, 7.7 mmol) was added drop wise to a solution of 1,4-dibromo-2,5-difluoro-benzene (2 g, 7.35 mmol) in dry ether at −78° C. under nitrogen atmosphere and the resulting mixture was stirred at −78° C. for 30 minutes. This was followed by the addition of DMF (0.85 ml, 11.03 mmol) in dry THF. The resultant was stirred at room temperature for 1 hour. The reaction was monitored by TLC (5% ethyl acetate in hexane). The reaction mixture was partitioned between ethyl acetate and saturated ammonium chloride. The organic layer was concentrated and purified by column chromatography on silica gel (2% ethyl acetate in hexane) to afford 600 mg of the product (37% yield).
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