Palladium-catalyzed cyanation of aryl halides: Recent developments and perspectives

The palladium-catalyzed cyanation of aryl halides is an elegant method for the preparation of benzonitriles. Since its discovery in 1973, this reaction has been the topic of several investigations. Nevertheless, the general methodology is still somewhat underdeveloped compared to other palladium-catalyzed coupling reactions. Here, we summarize important developments from 1997 until 2003 in this area. Recent contributions from our group include the development of palladium/phosphane/amine catalyst systems for the cyanation of aryl chlorides, the successful cyanation of aryl halides with acetone cyanohydrin and trimethylsilyl cyanide as cyanation reagents, and a general improvement of catalyst efficiency by using a continuous dosage of cyanide sources. (C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003.