2-BROMOBENZO[B]THIOPHENE

95-15-8

5394-13-8

To a solution of benzo[b]thiophene (2.0 g, 15 mmol) in tetrahydrofuran (20 mL) was slowly added n-butyllithium (2.5 M hexane solution, 12 mL, 30 mmol) dropwise at -70 °C and under nitrogen protection. The reaction mixture was stirred continuously at this temperature for 30 minutes. Subsequently, N-bromosuccinimide (5.3 g, 30 mmol) was added and the reaction system was slowly warmed from -70 °C to room temperature over 1 hour. Upon completion of the reaction, the reaction was quenched with saturated aqueous ammonium chloride solution (20 mL) followed by extraction with ethyl acetate (3 x 30 mL). The organic phases were combined, concentrated in vacuum, and the residue was purified by silica gel column chromatography [eluent: petroleum ether/ethyl acetate = 100:1] to afford 2-bromobenzothiophene (0.50 g, 16% yield) as a white solid.