Four-component, three-step cascade reaction: an effective synthesis of indazole-fused triazolo[5,1-c]quinoxalines

An efficient four-component, three-step cascade reaction was developed for the synthesis of indazole-fused triazolo[5,1-c]quinoxalines from o-azido aldehyde, o-iodoaniline, phenylacetylene, and sodium azide. The methodology involves the sequential formation of 2H-indazole, then azide–alkyne cycloaddition, followed by C–N coupling, and finally intramolecular cross-dehydrogenative C–C coupling. Notable features of this protocol include simple starting materials, reduced synthetic steps, and good yields.