Dimethylformamide → 2,6-Dibromo-4-fluorobenzaldehyde

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 a solution of isopropyl-magnesium 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 (hours). 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 104k as a white solid (20 g, 54%). 1H NMR (500 MHz, CDCl3) δ 10.23 (s, 1H), 7.48 (d, J=7.5, 2H).