n-Butyllithium (1.57 M hexane solution; 8.33 ml, 13.1 mmol) was added dropwise to a solution of 2-bromo-1,4-bis[(tetrahydropyran-2-yl)oxymethyl]benzene (3.55 g, 9.22 mmol) obtained from Example 1-(2) in tetrahydrofuran (30 ml) with stirring at −78° C. After the mixture was stirred at the same temperature for 20 minutes, carbon dioxide gas was introduced thereto for 40 minutes. The resulting mixture was stirred at the same temperature for 1 hour, and then the reaction was stopped by addition of a saturated aqueous solution of ammonium chloride. The mixture was warmed to 0° C., and then the product was extracted with ethyl acetate. The organic layer was washed with a saturated aqueous solution of sodium chloride, and the solvent was distilled off under reduced pressure to afford the residue. The residue was subjected to chromatography on a silica gel (100 g) column (eluent; ethyl acetate:hexane=1:3) to give the title compound (1.63 g, 50% yield) as a colorless oil.
