Synthesis of 6-Substituted-4-Hydroxy-2-pyridinones via Intramolecular Ketene Trapping of Functionalized Enamine-Dioxinones

The synthesis of various 6-substituted-4-hydroxy-2-pyridinones is reported. The functionalized keto-dioxinones were constructed via a diethylzinc mediated crossed Claisen condensation reaction and subsequent enamine formation, thermolysis, and cyclization–aromatization providing the pyridinone unit.