A Transition‐Metal‐Free Azide–Alkyne Cycloaddition/Aza‐Michael Addition Reaction to 1,2,3‐Triazole‐Fused Piperazin‐2‐Ones

A practical and efficient protocol for the construction of functionalized 1,2,3‐triazole‐fused piperazin‐2‐one derivatives has been developed. The transformation proceeds through an azide–alkyne cycloaddition/aza‐Michael addition cascade process. This operationally simple, transition‐metal‐free protocol features a broad substrate scope and good functional group tolerance. The resulting products can be readily transformed into structurally diversified 1,2,3‐triazole‐fused piperazin‐2‐one derivatives, underscoring the potential of this scaffold for constructing biologically relevant compounds.