4-Toluenesulfonyl chloride → Toluene-4-sulfonic acid 2-(4-bromo-phenyl)-2-cyano-2-methyl-ethyl ester

To a stirred solution of 2-(4-bromo-phenyl)-3-hydroxy-2-methyl-propionitrile (25 g, 104.17 mmol) in pyridine (225 mL) was added para-toluene sulphonyl chloride (29.79 g, 156.25 mmol) and the reaction stirred at room temperature for 16 h. The reaction mixture was diluted with ethyl acetate (300 mL), washed with a 2N aqueous hydrochloric acid solution (2×50 mL), water (2×100 mL), a saturated aqueous sodium bicarbonate solution (2×50 mL), dried over sodium sulfate, and concentrated in vacuo. Flash chromatography (10% ethyl acetate/hexanes) afforded toluene-4-sulfonic acid 2-(4-bromo-phenyl)-2-cyano-2-methyl-ethyl ester as a colorless liquid (35 g, 73%).