A mixture of the trifluoromethanesulfonic acid 3,3,4,4-tetramethylcyclopent-1-enyl ester (992 mg, 3.64 mmol) produced in Example (54a), 2-nitrophenylboronic acid (729 mg, 4.37 mmol), tetrakis(triphenylphosphine)palladium(0) (219 mg, 0.189 mmol), 2N aqueous solution of sodium carbonate (3.64 mL), toluene (12.5 mL) and ethanol (6.3 mL) was stirred for 6 hours at an external temperature of 90° C. under a nitrogen atmosphere. The reaction mixture was air-cooled to room temperature, and then ethyl acetate and brine were added and extraction was performed twice with ethyl acetate. The separated organic layer was dried over anhydrous sodium sulfate. The desiccant was filtered off and the filtrate was concentrated under reduced pressure. The resultant residue was purified by silica gel column chromatography (ethyl acetate/heptane) to give 891 mg of the title compound as a light brown oil.
