Under nitrogen protection, 9-(3-bromophenyl)-9H-carbazole (10.5 g, 1.0 equiv), pinacol ester of bis(boronic acid) (9.93 g, 1.2 equiv), potassium acetate (10.9 g, 3.0 equiv), and anhydrous dimethylsulfoxide (190 mL) were added to the reaction vial, heated to 60 °C and stirred for 15 min. Subsequently, [1,1'-bis(diphenylphosphino)ferrocene]palladium(II) dichloride dichloromethane complex (0.799 g, 0.03 equiv) was added. The reaction mixture was heated to 80 °C and the reaction was continuously stirred for 9 hours. After completion of the reaction, it was cooled to room temperature. Water (250 mL) and toluene (500 mL) were added to the reaction solution and mixed with stirring. The aqueous layer was separated and the aqueous layer was extracted twice with toluene. The organic layers were combined and dried by adding magnesium sulfate and activated clay. The desiccant was removed by filtration and the toluene was removed by concentration under reduced pressure. The resulting solid was washed with cold methanol and dried under reduced pressure to give the target product 9-(3-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)-9H-carbazole (9.86 g, 80% yield) as white crystals.
