Platinum Iodide-Catalyzed Formal Three-Component Cascade Cycloaddition Reactions between γ‑Aminoalkynes and Electron-Deficient Alkynes

Herein, we report a protocol for PtI2-catalyzed formal three-component cascade cycloaddition reactions between γ-aminoalkynes and electron-deficient alkynes to afford highly substituted cyclohexadiene-b-pyrrolidines in good yields. On the basis of the results of the control experiments and density functional theory calculations, we present a plausible mechanism that proceeds via two key intermediates. The overall transformation involves the cleavage and formation of multiple C–C and C–N bonds and a previously unreported reaction mode of a seven-membered nitrogen heterocyclic intermediate.