α‑Imino Gold Carbenes from 1,2,4-Oxadiazoles: Atom-Economical Access to Fully Substituted 4‑Aminoimidazoles

A novel
and atom-economical synthesis of fully substituted 4-aminoimidazoles
via gold-catalyzed selective [3 + 2] annulation of 1,2,4-oxadiazoles
with ynamides is reported. This protocol represents a new strategy
to access α-imino gold carbenes, which corresponds to an unprecedented
intermolecular transfer of N-acylimino nitrenes to
ynamides. Moreover, the reaction proceeds with 100% atom economy,
exhibits good functional group tolerance, and can be conducted in
gram scale.