KO<i>t</i>Bu-Promoted [4+2] Annulation-Dehydration Cascade Enabling the Construction of Diverse 2-Pyridone-Fused Uracils

A KO<i>t</i>Bu-promoted [4+2] annulation-dehydration cascade reaction has been developed, enabling the efficient synthesis of diverse 2-pyridone-fused uracils through a vinylogous enolization strategy involving <i>o</i>-quinodimethane (<i>o</i>QDM) dienolate intermediates. This method provides a simple yet robust approach for constructing structurally interesting fused <i>N</i>-heterocycles that incorporate two privileged scaffolds, both of which are widely recognized in drug discovery. Consequently, these compounds hold significant potential for biological and pharmacological applications. Moreover, further transformations of the products obtained from this process allow access to highly functionalized and structurally diverse uracil derivatives, expanding the scope of accessible chemical diversity.