The 300 mL round bottom flask, equipped with magnetic stirrer and refluxed condenser, was charged with 6-chlorobenzofuro[2,3-b]pyridine (2.04 g, 10 mmol), 3-(9-carbazolyl)carbazole (3.32 g, 10 mmol), Pd(OAc)2 (450 mg, 20 mol %), P(t-Bu)3 (10 mL of 1M solution in toluene, 10 mmol), potassium tert-buthoxide (1.92 g, 20 mmol) and 150 ml of xylene. The flask was filled with nitrogen, and the reaction mixture was heated to reflux and stirred under nitrogen atmosphere for 36 hours. Then the reaction was cooled down to room temperature, washed with water, filtered through silica plug and evaporated. The residue was subjected to column chromatography on silica gel, eluent hexane/ethyl acetate mixture 4:1, providing 3.01 g of 6-(9H-3,9′-bicarbazol-9-yl)benzofuro[2,3-b]pyridine as white solid, structure was confirmed by NMR and MS spectroscopy.
