Copper-Mediated Direct Aryl C–H Cyanation with Azobisisobutyronitrile via a Free-Radical Pathway

An unprecedented protocol for the copper-mediated direct cyanation of aryl C–H by employing 2,2′-azobisisobutyronitrile (AIBN) as a free radical "CN" source is presented. The protocol not only provides a more efficient pathway for the synthesis of aryl nitriles in terms of the yields and the loading amount of copper salts but also, more importantly, represents a novel strategy for aryl C–H cyanation via a CN free-radical mechanism as compared to the CN anion-participating protocols often reported.