To a solution of probucol (0.5 g, 0.97 mmol) in dimethylformamide (1.5 mL) were added ethyl iodoacetate (0.31 g, 1.45 mmol) and 40% potassium fluoride on alumina (0.7 g, 4.8 mmol). The mixture was stirred for 24 hours and then diluted with ether (25 mL), filtered and washed with water (2×5 mL). The ether layer was dried over MgSO4, filtered and concentrated. Silica gel chromatography (hexanes/ether 5:95) yielded 160 mg of {2,6-di-tert-butyl-4-[1-(3,5-di-tert-butyl-4-hydroxy-phenylsulfanyl)-1-methyl-ethylsulfanyl]-phenoxy}-acetic acid ethyl ester which was used directly for the next step of reaction.
