Nickel/Cobalt-Catalyzed Reductive Hydrocyanation of Alkynes with Formamide as the Cyano Source, Dehydrant, Reductant, and Solvent

A Ni/Co co-catalyzed reductive hydrocyanation of various alkynes was developed for the production of saturated nitriles. Hydrocyanic acid is generated in situ from safe and readily available formamide. Formamide played multiple roles as a cyano source, dehydrant, and reductant for the Ni-II pre-catalyst and vinyl nitriles, along with acting as the co-solvent in this reaction. Detailed mechanistic investigation supported a pathway via hydrocyanation of C equivalent to C bond and the subsequent reduction of C=C bond. Wide substrate scope, the employment of a cheap and stable nickel salt as pre-catalyst, a safe cyano source and convenient experimental operation render this hydrocyanation practical for the laboratory synthesis of saturated nitriles.