190 μl (1 mmol) of di-tert-butylphosphine chloride and then 112 mg (0.5 mmol) of palladium(II)acetate are added to a suspension of 26.3 g (50 mmol) of biphenyl-4-yl-(12,12-dimethyl-10-phenyl-10,12-dihydro-10-azaindeno[2,1-b]fluoren-7-yl)amine, 13.3 g (49 mmol) of 2-bromo-9,9-dimethylfluorene and 7.7 g (80 mmol) of sodium tert-butoxide in 500 ml of toluene, and the mixture is subsequently heated under reflux for 5 h. After cooling to 60° C., 500 ml of water are added, the organic phase is separated off, filtered through silica gel, evaporated virtually to dryness under reduced pressure at 80° C., and 300 ml of ethanol are then added. After cooling, the solid is filtered off with suction and then recrystallised five times from dioxane. Yield: 31.5 g (43 mmol), 88%, purity 99.9% (HPLC).
