To a solution of tert-butyl [2-(4-bromophenyl)ethyl][(2R)-2-(3-chlorophenyl)-2-hydroxyethyl]carbamate (500 mg) in 1,2-dimethoxyethane (6 ml) was added 5-formyl-2-thiopheneboronic acid (206 mg), tetrakis(triphenylphosphine)palladium (63 mg) and aqueous solution of sodium carbonate (2M, 1.0 ml), and the mixture was stirred at 80° C. for 7 hours under nitrogen. The mixture was diluted with ethyl acetate and water. The organic layer was separated, washed with brine, dried over magnesium sulfate and evaporated under reduced pressure. The residue was purified by column chromatography on silica gel (hexane/ethyl acetate=3/1) to give tert-butyl [(2R)-2-(3-chlorophenyl)-2-hydroxyethyl][2-[4-(5-formyl-2-thienyl)phenyl]ethyl]carbamate (187 mg).
