Under argon protection, sequentially NiCl2-6H2O (0.05 mmol, 11.9 mg), dppf (0.06 mmol, 33.3 mg), 5-chloro-2-methylbenzothiazole (0.2 mmol, 13.0 mg), DMAP (1.0 mmol, 122.2 mg), zinc cyanide (0.8 mmol, 93.9 mg) , p-chloroanisole (1.0 mmol, 140.6 mg) and acetonitrile (5.0 mL) were added to a 25.0 mL sealed tube. The reaction mixture was heated in an oil bath at 60°C for 6 hours. After completion of the reaction, it was cooled to room temperature and the reaction solution was filtered directly through a short silica gel column and washed with dichloromethane. The filtrate was concentrated and purified by silica gel column chromatography (wet sampling was used to avoid sample loss). The eluent ratio was petroleum ether/ethyl acetate = 20:1. 117.2 mg of 2-methyl-5-cyanobenzothiazole was obtained as a white solid in 88% yield, and 1H NMR showed a purity of >98%.
