Ung, G.; Mendoza-Espinosa, D.; Bertrand G. Novel Route to Ynamides: Stable Ligands Equivalent to Unstable Oxazol-4-Ylidenes. Chem. Commun. 2012, 48, 7088-7090.
Deprotonation of an oxazolium salt induces a ring opening process leading to the corresponding ynamide. Although the expected mesoionic carbene is not obtained, the acyclic ynamide readily reacts with various transition metals yielding robust mesoionic carbene complexes.