Bis(pinacolato)diboron (391 mg, 1.54 mmol), potassium acetate (412 mg, 4.5 mmol) and [1,1'-bis(diphenylphosphino)ferrocene]palladium(II) dichloride (102 mg, 0.14 mmol) were sequentially added to the reaction flask under nitrogen atmosphere. A solution of 2-chloro-4-bromobenzonitrile (300 mg, 1.4 mmol) in dioxane (15 mL) was then added. The reaction mixture was stirred at 80 °C for 12 hours. After completion of the reaction, the mixture was cooled to room temperature, filtered through diatomaceous earth and the filter cake was washed with ethyl acetate (50 mL). The filtrate was concentrated under reduced pressure and the resulting residue was purified by preparative thin layer chromatography on silica gel to afford the white solid product 3-chloro-4-pinacolboronate benzonitrile (73 mg, 20% yield). The product was characterized by 1H-NMR (400 MHz, CDCl3): δ 7.78 (d, J = 7.6 Hz, 1H), 7.62 (d, J = 1.2 Hz, 1H), 7.52 (dd, J = 7.6 Hz, 1.2 Hz, 1H), 1.37 (s, 12H) ppm.
