[F:1][C:2]([F:8])([F:7])[C:3]([F:6])([F:5])I.C[Li].[Br-].[Li+].[Br:13][C:14]1[CH:15]=[CH:16][C:17]([F:28])=[C:18]([CH:20]=[CH:21][C:22](N(OC)C)=[O:23])[CH:19]=1>>[Br:13][C:14]1[CH:15]=[CH:16][C:17]([F:28])=[C:18]([CH:20]=[CH:21][C:22](=[O:23])[C:3]([F:6])([F:5])[C:2]([F:8])([F:7])[F:1])[CH:19]=1To a saturated solution of pentafluoroiodoethane (0.84 M, in diethyl ether) (15.3 mL, 13.3 mmol), was slowly added a solution of methyllithium/lithium bromide (1.5 M, in diethyl ether) (8.9 mL, 13.3 mmol) under nitrogen atmosphere at −78° C. The reaction mixture was stirred for 20 minutes and then 3-(5-bromo-2-fluoro-phenyl)-N-methoxy-N-methylacrylamide (1.3 g, 4.4 mmol, in tetrahydrofuran 10.0 mL) prepared in Step 3 was slowly added thereto at −78° C. The reaction mixture was stirred at room temperature, quenched with distilled water, acidified by a 10% potassium hydrogen sulfate solution (pH=5), and then extracted with ethyl acetate. The extract was washed with a saturated solution of sodium hydrogen carbonate, dried on anhydrous magnesium sulfate, and then concentrated under reduced pressure to give a yellow liquid residue. The resulting residue was purified by silica gel column chromatography (eluent: ethyl acetate/n-hexane=1/10) to give 620.0 mg of the titled compound as a yellow liquid.
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