A Green Approach for 1,2,3-Triazole-Fused Quinolinones via Metal-Free Cascade [3+2] Cycloaddition/C-N Coupling Reaction

A metal-free cascade reaction of 1-(8-halonaphthalen-1-yl)prop-2-yn-1-ones with sodium azide has been developed for the construction of quinolinone fused triazole frameworks. The reaction proceeded smoothly via an intramolecular metal-free version of the azide-alkyne [3 + 2] cycloaddition. A variety of quinolinone fused triazole derivatives were prepared in good to excellent yields under metal-free conditions. The practicality of this metal-free protocol was further evaluated by gram scale synthesis of quinolinone fused triazole derivatives.