Cascade Synthesis of Pyridoquinazolinones: A Pd-Catalyzed Double C-N Bond Formation Strategy via Intramolecular 1,6-Conjugate Addition.

A cascade process has been designed to access pyridoquinazolinone derivatives through a Pd-catalyzed annulation reaction between readily accessible 2-bromo-p-quinone methides and commercially available 2-aminopyridines. This one-pot process comprises Pd-catalyzed C-N bond formation, followed by a second C-N bond formation through intramolecular 1,6-conjugate addition, affording the various functionalized pyridoquinazolinones in good yields. This synthetic method has several advantages, including step economy, broad substrate scope, and an open-air reaction.