To a 250 mL round bottom flask was added 5-bromo-2-cyanopyridine (3.0 g, 16.39 mmol), bis(pinacolato)diboron (4.58 g, 18.03 mmol), potassium acetate (5.47 g, 55.74 mmol), and dimethyl sulfoxide (100 mL). After degassing for 20 min, [1,1'-bis(diphenylphosphino)ferrocene]palladium dichloride dichloromethane complex (1.39 g, 1.64 mmol) was added. The reaction mixture was stirred at 80 °C for 24 h, followed by continued stirring at room temperature for 3 days. Upon completion of the reaction, 50 mL of water was added and the product was extracted with ethyl acetate. The organic phases were combined, washed with saturated brine, dried over anhydrous sodium sulfate and concentrated under reduced pressure. The dark residue was purified by fast column chromatography (eluent: 20% acetone/hexane) to give a red solid. The solid was ground with hexane to give 1.72 g (46% yield) of the target product 5-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-2-cyanopyridine as a light pink solid.
