The development of a nickel-catalyzed
reductive alkyne hydrocyanation
is described using 2-methyl-2-phenylmalononitrile (MPMN), a C-bound
electrophilic transnitrilation reagent. Reproducibility issues led
to the detection of oxidized hemiaminal impurities within N,N-dimethylacetamide. These impurities
release formaldehyde in situ, which was ultimately identified as a
critical reaction additive. A range of diaryl and aryl-alkyl alkynes
underwent hydrocyanation. Mechanistic experiments revealed that formaldehyde
and MPMN undergo a Ni-catalyzed reductive coupling of two π-components,
leading to the controlled release of glycolonitrile as the active
cyanating agent.