FeCI3‐promoted [3+3] cycloaddition: Efficient preparation of 1,2‐dihydro‐2‐oxo‐3‐pyridinecarboxylate and 1,2‐dihydro‐2‐oxo‐3‐pyridinecarboxamide derivatives

A facile approach was developed on assembly of the 2-pyridone nucleus by ferric chloride promoted [3+3] cycloaddition in propionic acid. The tandem process involves cyclization of Michael adduct followed by aromatization. Thus, different substituted 1,2-dihydro-2-oxo-3-pyridinecarboxylate and 1,2-dihydro-2-oxo-3-pyridinecarboxamide derivatives were prepared in good yields from various enones with malonamic ester and malonamide, respectively