A reaction vessel equipped with a dropping funnel was charged with 40 ml of dehydrated tetrahydrofuran and 2.35 g (6.08 mmol) of octamethyloctahydrodibenzofluorene synthesized by a method described in (i) of Synthetic Example 1 under nitrogen atmosphere, and 4.62 ml (7.30 mmol) of a hexane solution of n-butyllithium of 1.58 mol/L was added dropwise and stirred while cooling the above solution at 0° C. 1,3-Dimethyl-2-imidazolidinone 0.86 ml (7.90 mmol) was added to the above solution and stirred for 30 minutes. Then, a solution prepared by dissolving 2.00 g (6.68 mmol) of 6,6-di(p-chlorophenyl)fulvene in 30 ml of dehydrated tetrahydrofuran was [put] placed in the dropping funnel and added dropwise while cooling at −78° C., and the solution was stirred for one day while slowly allowing it to return to room temperature. This reaction solution was extracted with diethyl ether, and the separated organic layer was washed with 1N hydrochloric acid, a saturated sodium hydrogen carbonate aqueous solution and a saturated salt solution and dried over anhydrous magnesium sulfate. Then, magnesium sulfate was removed by filtration, and the solvent contained in the filtrate was removed by distillation under reduced pressure by means of a rotary evaporator. The residue was purified through a silica gel column and then recrystallized from toluene to obtain a targeted product (amount obtained: 0.714 g, yield: 17%). The targeted product was identified by means of 1H-NMR and FD-MS spectra.
