A solution of 3-(2-chloroethyl)benzoyl chloride (2.43 g, 12.0 mmol) in ethyl acetate (10 mL) was added to a solution of 3-(tert-butyldimethylsiloxymethyl)benzylamine (3.01 g, 12.0 mmol) and triethylamine (3.3 mL, 24 mmol) in ethyl acetate (20 mL) at 0° C., and the resulting mixture was stirred at the same temperature for 2 hours and then at room temperature for 3 hours. The reaction mixture was diluted with ethyl acetate, washed successively with a 5% aqueous potassium hydrogensulfate solution, water, a saturated aqueous sodium hydrogencarbonate solution and a saturated aqueous sodium chloride solution, dried over anhydrous sodium sulfate, and then concentrated under reduced pressure. The residue was purified by a silica gel column chromatography (silica gel 200 mL; hexane/ethyl acetate=10/1 to 3/1) to obtain the title compound (3.74 g, 75%) as a white solid.
