Under a nitrogen atmosphere, 50 mL of dehydrated tetrahydrofuran was added to 3.50 g (8.02 mmol) of 2,7-dibromo-3,6-ditert-butyl-fluorene synthesized in Synthesis Example 1-1(i), 0.186 g (0.20 mmol) of Pd2(dba)3, 0.115 g (0.57 mmol) of P(tBu)3, and 6.81 g (32.1 mmol) of tripotassium phosphate, and the mixture was stirred at room temperature for 20 minutes. To the solution, a solution of 2.73 g (20.0 mmol) prepared by dissolving o-tolylboronic acid in 15 mL of dehydrated tetrahydrofuran was added. Subsequently, the mixture was heated to reflux for 72 hours, left to be naturally cooled, and then 1N hydrochloric acid was added in an ice bath to terminate the reaction. Thereafter, diethylether was added to perform liquid-liquid phase separation. The aqueous layer was extracted twice with diethylether and the resultant was combined with the organic layer obtained previously. Then, the resultant liquid 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. Subsequently, the solvent was distilled off, and the resultant was subjected to separation by silica gel chromatography to obtain a target product as a white powder (yield 0.532 g (14%)). The target product was identified by 1H-NMR.
