A Direct Route into Fused Imidazo-diazines and Imidazo-pyridines Using Nucleophilic Nitrenoids in a Gold-Catalyzed Formal [3 + 2]-Dipolar Cycloaddition

Pyridinium <i>N</i>-(hetero­aryl)­aminides can be employed as robust and practical synthetic equivalents of nucleophilic 1,3-<i>N</i>,<i>N</i>-dipoles in a formal cycloaddition onto electron-rich alkynes under gold catalysis. Convergent and regioselective access to five types of imidazo-fused heteroaromatics is provided from the appropriate aminide. The efficient transformation accommodates significant structural variation around the aminide, ynamide, or indolyl-alkyne reactants and tolerates sensitive functional groups