A mixture of 2-(4-(4-chlorobenzoyl)phenoxy)-2-methylpropanoic acid (10.0 g, 31.4 mmol), sodium bicarbonate (13.2 g, 47.1 mmol, 1.5 eq) and tetrabutylammonium hydrogensulfate (2.1 g, 6.3 mmol, 0.2 eq) in water (150 mL) was stirred at room temperature for 15 min. Dichloromethane (150 mL) was added and the mixture was cooled in ice. Chloromethyl sulfochloridate (4.2 mL, 47.1 mmol, 1.5 eq) was added and the mixture was stirred overnight at room temperature. The layers were separated, the organic phase was washed with water (50 mL) and brine, then dried over sodium sulfate. The drying agent was filtered off and the solution was concentrated by rotary evaporation to leave a thick oil. Hexane (50 mL) and seeds were added and rotary evaporation was continued at room temperature to leave chloromethyl 2-(4-(4-chlorobenzoyl)phenoxy)-2-methylpropanoate 1 as a white solid (11.6 g, 101% yield). 1H-NMR (CDCl3) δ 7.73 (d, 2 H), 7.70 (d, 2 H), 7.44 (d, 2 H), 6.87 (d, 2 H), 5.77, (s, 2 H), 1.70 (s, 6 H) ppm.
