First Synthesis of N‐Methylene‐Ynamines (2‐Azabut‐1‐en‐3‐ynes)

Abstract
An addition to the family of C3H3N isomers is HCCNCH2, the skeletal unit of the title compounds 3. Compared to the ynamines these first N‐methylene‐ynamines contain an additional conjugated CN bond. The compounds 3 have now been obtained from the cuprate 1 and the oxime esters 2. For a reliable differentiation, the isomeric propargylideneamine PhCCC(Ph)NPh was also synthesized. Quantum mechanical calculations make it possible to predict the energy content of these compounds (a, R  Ph, R′  Me; b, R  Me, R′  H). equation image