To a mixture of 4-[3-[6-(3-bromo-5-ethoxy-phenoxy)-hexyl]-2-(2-ethoxycarbonyl-ethyl)-phenoxy]-butyric acid ethyl ester (155 mg, 0.255 mmol), 3,4-methylenedioxybenzeneboronic acid (85 mg, 0.51 mmol), [1,1′-bis(diphenylphosphino)ferrocene]dichloropalladium(II) (73 mg, 0.1 mmol), and cesium carbonate (166 mg, 0.51 mmol) was added dimethoxyethane (10 mL) at room temperature under nitrogen atmosphere. The resulting brown reaction mixture was heated to 96° C. and stirred for 15 h at which time the TLC analysis of the reaction mixture indicated the absence of starting material. Then, the reaction mixture was cooled to room temperature and diluted with water (50 mL) and ethyl acetate (50 mL). The two layers were separated and the aqueous layer was extracted with ethyl acetate (50 mL) and the combined organic extracts were washed with water (50 mL) and brine solution (50 mL). The organic layer was dried over anhydrous magnesium sulfate and filtration of the drying agent and removal of the solvent under vacuum gave the colored residue which was purified by using an ISCO 40 column, eluting with 0-25% ethyl acetate in hexanes to obtain 4-[3-[6-(3-benzo[1,3]dioxol-5-yl-5-ethoxy-phenoxy)-hexyl]-2-(2-ethoxycarbonyl-ethyl)-phenoxy]-butyric acid ethyl ester (165 mg, 99%) as a colorless viscous oil: ES(+)-LRMS m/e calcd for C38H48O9 (M+Na)+ 671.3190. found 671.3185.
