One-Pot Three-Component Synthesis of Enamine-Functionalized 1,2,3-Triazoles via Cu-Catalytic Azide-Alkyne Click (CuAAC) and Cu-Catalyzed Vinyl Nitrene Transfer Sequence

A number of enamine-functionalized 1,2,3-triazole derivatives have been prepared via the Cu-catalyzed three-component reaction of terminal alkyne, azide, and 2H-azirine. The reaction proceeds through insertion of vinyl nitrene into the C-Cu bond of the triazolyl-Cu species, providing an efficient and step- and atom-economic approach to the enamine-bearing polysubstituted 1,2,3-triazoles. The resulting triazoles were easily transformed to trisubstituted pyrazoles in the presence of a Rh catalyst.