A mixture of tert-butyl 3-[4-[(3-bromobenzyl)oxy]phenyl]propanoate (3.5 g, 8.94 mmol), 2-formylphenylboronic acid (1.47 g, 9.83 mmol), tetrakistriphenylphosphine palladium (413 mg, 0.36 mmol), 2N potassium carbonate aqueous solution (7 mL), ethanol (7 mL) and toluene (70 mL) was stirred under an argon atmosphere at 80° C. for 14 hrs. The reaction mixture was cooled, diluted with ethyl acetate, washed with water, dried, and concentrated under reduced pressure. The residue was purified by silica gel column chromatography (hexane/ethyl acetate=10/1-4/1) to give the title compound (3.62 g, 97%) as a colorless oil.
