Copper-catalyzed domino halide exchange-cyanation of aryl bromides.

An efficient copper-catalyzed domino halogen exchange-cyanation procedure for aryl bromides was developed utilizing 10 mol % CuI, 20 mol % KI, 1.0 equiv of the inexpensive N,N'-dimethylethylenediamine as ligand, and 1.2 equiv of NaCN in toluene at 110 degrees C. The new method represents a significant improvement over the traditional Rosenmund-von Braun reaction: the reaction conditions are much milder, and the use of stoichiometric amounts of copper(I) cyanide and polar solvents is avoided; therefore the isolation and purification of the aromatic nitrile products is greatly simplified. In addition, the new method exhibits excellent functional group compatibility comparable to that of the analogous Pd-catalyzed cyanation methodology.