5-bromo-7-fluoro-1H-indole

321-23-3

1826-67-1

883500-73-0

Vinylmagnesium bromide (1M solution in THF, 13.62 mL, 13.62 mmol) was added slowly and dropwise to a solution of 4-bromo-2-fluoro-1-nitrobenzene (1.0 g, 4.54 mmol) in tetrahydrofuran (THF, 20 mL) at -40 °C. The reaction mixture was stirred at this temperature for 60 minutes. Upon completion of the reaction, the reaction was quenched by the addition of saturated aqueous ammonium chloride (NH4Cl) and the mixture was extracted with ethyl acetate (EtOAc, 2 x 20 mL). The organic layers were combined, dried with anhydrous sodium sulfate (Na2SO4) and concentrated to dryness under reduced pressure. Purification by fast column chromatography (silica gel, ethyl acetate: petroleum ether = 9:1) afforded 5-bromo-7-fluoro-1H-indole as a gel solid (0.24 g, 25% yield).