Palladium-catalyzed Cyanation of Aryl Halides

Cheng et al. have reported the palladium-catalyzed cyanation of aryl halides. According to their results, in the presence of [1,2-bis(diphenylphosphino)ethane]palladium(II) dichloride catalyst, formic acid and sodium formate as an acid and an additive, respectively, aryl halides react with cuprous thiocyanate to provide the corresponding aromatic nitriles in good yields. In this reaction, even when using aryl boronic acids instead of aryl halides, the reaction successfully proceeds and the dihydroxyboryl groups are directly replaced with the cyano group. Since cuprous thiocyanate is an inexpensive and nontoxic cyanide source, this protocol is a novel and safe method to access aromatic nitriles.