One-Pot Two-Step Multicomponent Process of Indole and Other Nitrogenous Heterocycles or Amines toward α‑Oxo-acetamidines

A cesium carbonate promoted three-component reaction of N–H containing heterocycles, primary or secondary amines, arylglyoxaldehydes, and anilines is reported. The key step involves a tandem sequence of N-1 addition of a heterocycle or an amine to preformed α-iminoketones, followed by an air- or oxygen-mediated oxidation to form α-oxo-acetamidines. The scope of the reaction is enticingly broad, and this novel methodology is applied toward the synthesis of various polycyclic heterocycles.