In a 50-mL three-neck flask, 0.56 g (1.5 mmol) of 2-(3-bromophenyl)dibenzo[f,h]quinoline, 0.46 g (1.5 mmol) of 3-(dibenzothiophen-4-yl)phenylboronic acid, 58 mg (0.19 mmol) of tri(ortho-tolyl)phosphine, 15 mL of toluene, 1.5 mL of ethanol, and 1.5 mL of a 2M aqueous solution of potassium carbonate were put. The mixture was degassed by being stirred under reduced pressure, and the air in the flask was replaced with nitrogen. Then, 17 mg (77 μmol) of palladium(II) acetate was added to this mixture, and the mixture was stirred at 80° C. for 9 hours under a nitrogen stream. After a predetermined time, water and toluene were added to this mixture, and the resulting solid was collected by suction filtration. A toluene solution of the obtained solid was suction-filtered through alumina and Celite, and the filtrate was concentrated to give a yellow solid. A methanol suspension of the obtained solid was irradiated with ultrasonic waves, and a solid was collected by suction filtration, so that the object of the synthesis was obtained as 0.52 g of white powder in 63% yield.
