Chelation-Assisted Interrupted Copper(I)-Catalyzed Azide–Alkyne–Azide Domino Reactions: Synthesis of Fully Substituted 5‑Triazenyl-1,2,3-triazoles

We describe the synthesis of 1,4-(disubstituted)-5-triazenyl-1,2,3-triazoles through a ligand-free domino copper­(I)-catalyzed azide–alkyne–azide process of chelating aryl azides bearing N–PO, PO, and SO₃H groups at the ortho position with a wide variety of acetylenes. DFT calculations reveal that Cu-chelation is a crucial factor in the interception of the CuAAC intermediate by the azide. The crystal structure of the catalytic species has been determined by X-ray diffraction.