190 μl (1 mmol) of chlorodi-tert-butylphosphine and then 112 mg (0.5 mmol) of palladium(II) acetate are added to a suspension of 15.3 g (50 mmol) of 5-bromobenzo[c]phenanthrene, 10.2 g (60 mmol) of diphenylamine 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 the mixture has been cooled to 60° C., 500 ml of water are added, the organic phase is separated off, filtered through silica gel, evaporated virtually to dryness at 80° C. in vacuo, and 300 ml of ethanol are then added. After cooling, the solid is filtered off with suction. The product is purified by recrystallisation from dioxane five times (about 8 ml/g). Yield: 12.6 g (32 mmol), 64.1%, purity 99.9% (HPLC).
