Under a nitrogen atmosphere, dehydrated tetrahydrofuran was added to 0.783 g (2.55 mmol) of 2,7-dimethyl-3,6-ditert-butyl-fluorene, and the mixture was stirred. This solution was cooled in an ice bath, and 1.85 mL (2.85 mmol) of a 1.54 mol/L hexane solution of n-butyllithium was added. The mixture was stirred at room temperature for 2 hours. The resulting orange-colored solution was cooled to −78° C. in a dry ice/methanol bath, and a solution prepared by dissolving 0.571 g (3.00 mmol) of 6,6-di(n-butyl)fulvene synthesized in Synthesis Example 1-2 (i) in 15 mL of dehydrated tetrahydrofuran was added dropwise over 20 minutes, and the mixture was stirred for 2 hours. 100 mL of 1 N hydrochloric acid was added to the resulting orange-colored solution to terminate the reaction. 100 mL of diethyl ether was added to perform liquid-liquid phase separation, and the soluble fraction was extracted. This organic layer was washed two times with a saturated aqueous solution of sodium hydrogen carbonate, two times with water, and once with saturated brine, and dried over magnesium sulfate. The solvent was distilled off, and the residue was recrystallized from diethyl ether/methanol to obtain a target product as a white powder (yield 0.63 g (50%)). The target product was identified by 1H-NMR and FD-MS spectroscopy.
