Radical Reactions of N-Heterocyclic Carbene Boranes with Organic Nitriles: Cyanation of NHC-Boranes and Reductive Decyanation of Malononitriles

The observation that NHC-boryl radicals abstract cyano groups from various organic nitriles has been parlayed into two complementary transformations. In the main group chemistry aspect, reactions of various NHC-boranes with simple organic dinitriles selectively provide stable NHC-boryl mono- or dinitriles, depending on the nitrile source. In the organic synthesis aspect, reaction of malononitriles and related derivatives with readily available 1,3-dimethylimidazol-2-ylidene borane provides reductively decyanated products in good yields.