[Synthesis]
General procedure for the synthesis of 2-chloro-6-phenylnicotinonitrile from (4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)benzene and 2,6-dichloronicotinonitrile: 2,6-dichloronicotinonitrile (0.865 g) and 4,4,5,5-tetramethyl-2-phenyl-1,3,2-dioxaborolane (1.021 g) were dissolved in a mixture of glycol dimethyl ether (60 mL) and water (20 mL) in a solvent mixture. Sodium bicarbonate (1 M) and [1,1'-bis(diphenylphosphino)ferrocene]palladium dichloride (0.366 g) were added, and the reaction mixture was heated to 90 °C under argon protection for 6 hours. After completion of the reaction, the aqueous phase was separated and extracted with ethyl acetate. The organic phases were combined, washed with saturated aqueous sodium chloride solution, dried over anhydrous sodium sulfate and filtered. The residue was purified by column chromatography (eluent: petroleum ether/ethyl acetate, 99:1 to 95:5, v/v) to afford 2-chloro-6-phenylnicotinonitrile (0.680 g, 63.4% yield) as a white solid. |