Ruthenium-Catalyzed Direct and Selective C–H Cyanation of <i>N</i>‑(Hetero)aryl-7-azaindoles

An efficient, highly regioselective, and scalable ruthenium-catalyzed o-aryl C–H mono-cyanation of N-aryl-7-azaindoles to form N-(2-cyanoaryl)-7-azaindoles has been developed through N-directed ortho C–H activation using N-cyano-N-phenyl-p-toluenesulfonamide as cyanating reagent in the presence of AgOTf and NaOAc in DCE. A range of substrates has furnished cyanated azaindoles in good to excellent yields under the simple reaction conditions. Involvement of C–H metalation has been supported by a kinetic study. This methodology provides easy access to a class of pharmaceutically significant molecules and their precursors.