2-Fluorobenzeneboronic acid (4.48 g) and tetrakis(triphenylphosphine)palladium (740 mg) were added to a solution of ethyl 2-trifluoromethanesulfonyloxycyclopent-1-enecarboxylate obtained in Preparation Example 3-(1) in toluene. Then, ethanol (100 mL) and a 1 N sodium carbonate solution (32 mL) were added to the reaction solution, followed by replacement of the reaction atmosphere with nitrogen. The reaction solution was heated to 85° C. and stirred overnight. The reaction solution was cooled to room temperature, followed by extraction with ethyl acetate. The organic layer was dried over anhydrous magnesium sulfate. The drying agent was removed by filtration and the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography to obtain the title compound (7.60 g).
