Mild and Efficient Copper-Catalyzed Cyanation of Aryl Iodides and Bromides

An efficient copper‐catalyzed cyanation of aryl iodides and bromides is reported. Our system combines catalytic amounts of both copper salts and chelating ligands. The latter, which have potential nitrogen‐ and/or oxygen‐binding sites, have never previously been used in this type of reaction. A protocol has been developed that enables the cyanation of aryl bromides through the copper‐catalyzed in situ production of the corresponding aryl iodides using catalytic amounts of potassium iodide. Aryl nitriles are obtained in good yields and excellent selectivities in relatively mild conditions (110 °C) compared with the Rosenmund–von Braun cyanation reaction. Furthermore, the reaction is compatible with a wide range of functional groups including nitro and amino substituents. The protocol reported herein involves two main innovations: the use of catalytic amounts of ligands and the use of acetone cyanohydrin as the cyanating agent in copper‐mediated cyanation reactions. The high‐yielding cyanation of aryl iodides and bromides is efficiently performed by using catalytic amounts of copper salts and bi‐, tri‐, or tetradentate ligands. The cyanation of aryl bromides is achieved by the copper‐catalyzed in situ production of the corresponding aryl iodides in the presence of catalytic amounts of potassium iodide (see scheme). This protocol involves two main innovations: 1) the use of catalytic amounts of ligands and 2) the use of acetone cyanohydrin as the cyanating agent in copper‐mediated cyanation reactions.