HOAc-Mediated Cyclocondensation of 2‑Formylazaarenes and Cyclic Amines. Synthesis of Pyrrolo[1,2‑a]azaarenes

In this paper, a concise, easy-operational, high-yield, one-pot method for the synthesis of pyrrolo­[1,2-a]­azaarenes is described by a straightforward HOAc-mediated double condensation of substituted 2-formylazaarenes (2 equiv) and cyclic amines (1 equiv) in refluxing toluene. Only water is generated as a byproduct. A plausible mechanism is proposed and discussed. This protocol provides a highly effective annulation via two carbon–nitrogen (C–N) and one carbon–carbon (C–C) bond formations.