[Br:1][C:2]1[CH:7]=[C:6]([F:8])[CH:5]=[C:4]([Br:9])[C:3]=1I.C([Mg]Cl)(C)C.CN([CH:19]=[O:20])C>C1(C)C=CC=CC=1>[Br:1][C:2]1[CH:7]=[C:6]([F:8])[CH:5]=[C:4]([Br:9])[C:3]=1[CH:19]=[O:20]To a solution of 1,3-dibromo-5-fluoro-2-iodobenzene (50 g, 132 mmol) in anhydrous toluene (300 mL) cooled at −35° C. was added the solution of isopropylmagnesium chloride (84 mL, 171 mmol, 2.0M in Et2O) over 30 minutes while maintaining the internal temperature below −25° C. A clear brown solution was obtained and the stirring was continued for 1.5 h at −25° C. Then anhydrous DMF (34 mL, 436 mmol) was added over a period of 30 minutes. The reaction mixture was warmed to 10° C. (room temperature) over 1 h and stirred at this temperature for 1.5 h. It was then quenched with 3.0M HCl and followed by the addition of ethyl acetate. The organic layer was separated and evaporated under reduced pressure. The residue was purified by silica-gel column chromatography eluting with petroleum ether/ethyl acetate (from 50:1 to 20:1) to give 101h as a white solid (20 g, 54%).
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