Copper-catalyzed C-O bond cleavage and cyclization: synthesis of indazolo[3,2-b]quinazolinones

The first example of a copper-catalyzed halogen-free protocol to construct indazolo[3,2-b]quinazolinones was developed through sequential inert C-O bond cleavage followed by intramolecular C-N bond formation. This protocol represents an efficient synthetic tool for accessing a more diverse range of functionalized indazolo[3,2-b]quinazolinones. The structure of the newly synthesized indazolo[3,2-b]quinazolinones was unambiguously confirmed by X-ray crystal diffraction analysis.