Cu(I)–Pd(II)-Catalyzed Cycloaddition–Fusion of 1-Iodoalkynes and Azides: One-Pot Synthesis of Fused Tricyclic Heterosystems

An unprecedented, one-pot regioselective synthesis of 1,2,3-triazole-fused heterocycles through Cu(I)–Pd(II) cycloaddition–fusion of 1-iodoalkynes and organic azides is described. The method presents a convenient heteroannulation approach towards the synthesis of polycyclic frameworks from easily accessible substrates.