Easy access to 5-cyanotriazoles <i>via</i> Pd-catalyzed cyanation of 5-iodotriazoles

A straightforward approach for the attachment of a nitrile moiety to the 1,2,3-triazole core has been developed. The protocol is based on the cyanation of 5-iodo-1,2,3-triazoles which are readily accessible by Cu-catalyzed azide-iodoalkyne cycloaddition. Halogen substitution occurs smoothly with KCN as a cyanide source using a Pd(0)-Dpephos catalytic system. The reaction tolerates a variety of functional groups as well as some sensitive heterocyclic scaffolds and affords the target 5-cyano-1,2,3-triazoles in yields of up to 99%. Further transformations of the nitrile group enable an easy preparation of 1,2,3-triazoles bearing diverse moieties, including amides, amines, and some azaheterocycles.