B. Phosphorus tribromide (PBr3, 0.23 mL, 2.42 mmol) was added slowly and dropwise to a stirring solution of benzothiophene-3-ylmethanol (400 mg, 2.44 mmol) in ether (12 mL) at 0 °C. The reaction mixture was continued to be stirred at 0 °C for 30 min, then brought to room temperature and held for 45 min. The reaction mixture was poured into a mixture of ice water and ether, and the organic phase was separated, washed with saturated brine, dried over anhydrous sodium sulfate, and concentrated under reduced pressure to afford 3-(bromomethyl)benzo[b]thiophene as a light-colored solid (404 mg, 73% yield).