General and Mild Nickel-Catalyzed Cyanation of Aryl/Heteroaryl Chlorides with Zn(CN)2: Key Roles of DMAP

Abstract

A new and general nickel-catalyzed cyanation of hetero(aryl) chlorides using less toxic Zn(CN)₂ as the cyanide source has been developed. The reaction relies on the use of inexpensive NiCl₂·6H₂O/dppf/Zn as the catalytic system and DMAP as the additive, allowing the cyanation to occur under mild reaction conditions (50-80 °C) with wide functional group tolerance. DMAP was found to be crucial for successful transformation, and the reaction likely proceeds via a Ni(0)/Ni(II) catalysis based on mechanistic studies. The method was also successfully extended to aryl bromides and aryl iodides.