Primary α-Phosphino- and α-Arseno-Nitriles, Analogues of α-Aminonitriles

More than 170 years after the synthesis of α-aminonitriles by the reaction of Strecker, α-phosphinonitriles, and α-arsenonitriles have been prepared and characterized by NMR and IR spectroscopy. For the simplest derivatives, the reaction was carried out by reaction of cyanomethyltributylstannane with phosphorus or arsenic trichloride, followed by a chemoselective reduction of the dichlorophosphine and dichloroarsine formed to the corresponding primary phosphine and arsine. The phosphinoacetonitrile can be stored at -80 °C for months in its pure state, but arsenoacetonitrile decomposes at this temperature. Chiral compounds can be synthesized from C-substituted cyano-1-alkyltributylstannanes. In ¹H NMR spectroscopy, these chiral phosphines and arsines display diastereotopic protons for the PH₂ and AsH₂ groups, a property never observed for the NH₂ group of α-aminonitriles. This work paves the way for further studies on the chemistry of these compounds, including a comparative chemistry of these phosphorus and arsenic derivatives with the well-known α-aminonitriles.