Copper‐Catalyzed Guanylation by Ring Extension of 4‐Hydroxyquinazoline for the Synthesis of Quinazolino[3,2‐a]quinazolinones

Abstract This work reports a new method for the synthesis of quinazolino[3,2‐ a ]quinazolinone derivatives under ligand‐free copper‐catalyzed guanylation through C−H functionalization. The reaction provides a convenient protocol which can be applied to a broad range of substrates providing the corresponding products in good to excellent yields. Additionally, this process provides a number of benefits, including minimal waste, rapid reaction times, and readily available starting material.