A solution of benzenesulfonyl chloride (1.92 mL, 15.0 mmol) in toluene (15.0 mL) was slowly added dropwise to a mixed system of toluene (30.0 mL) containing pyrrole (0.69 mL, 10.0 mmol), tetrabutylammonium hydrogensulfate (0.34 g, 1.0 mmol), and a 50% aqueous sodium hydroxide solution (10.0 mL) over a period of 15 min. The reaction mixture was stirred at room temperature and the progress of the reaction was monitored by thin layer chromatography (TLC).After 3 h, TLC analysis indicated that the reaction was complete. Subsequently, the two phases of the reaction solution were separated and the organic phase was washed sequentially with water and saturated saline, dried over anhydrous sodium sulfate, filtered and concentrated under reduced pressure. The crude product was purified by fast column chromatography (silica gel as stationary phase and 30% dichloromethane/hexane as eluent) to afford 1.81 g (87% yield) of the target compound 1-phenylsulfonylpyrrole as a white solid. Melting point: 86-87°C; 1H NMR (300 MHz, CDCl3) δ 6.30 (m, 2H), 7.17 (m, 2H), 7.50 (m, 2H), 7.57 (m, 1H), 7.84 (m, 1H), 7.87 (m, 1H).
