General procedure for the synthesis of 2,4,6-trichlorobenzonitrile from 1-iodo-2,4,6-trichlorobenzene and zinc cyanide: 1-iodo-2,4,6-trichlorobenzene (1500 mg, 4.88 mmol), zinc cyanide (345 mg, 2.94 mmol) and tetrakis(triphenylphosphine)palladium(0) (282 mg, 0.244 mmol) were added to anhydrous DMF (30 mL). The reaction mixture was heated to 85 °C and stirred overnight. After completion of the reaction, it was cooled to room temperature, diluted with toluene and washed sequentially with 2N aqueous ammonium hydroxide solution (3 times) and saturated aqueous sodium chloride solution. The organic phase was dried over anhydrous sodium sulfate and concentrated under reduced pressure. The crude product was purified by silica gel column chromatography to afford 2,4,6-trichlorobenzonitrile (850 mg, 84% yield) using n-hexane/dichloromethane as eluent. The structure of the product was confirmed by 1H NMR (400 MHz, CDCl3): δ 7.76 (s, 1H), 7.65 (s, 1H).
