Copper-catalyzed γ-selective yne-allylic substitution of vinyl ethynylethylene carbonates towards a formal [3 + 3] cycloaddition

Selective nonclassic propargylic substitutions have been a research focus in recent years. Herein, we developed a tandem γ-selective propargylic substitution and ring closure reaction of vinyl ethynylethylene carbonates (VEECs), efficiently synthesizing a series of 4H-pyran compounds. Additionally, the synthetic applications demonstrated that the products have significant synthetic potential in the synthesis of spirocyclic compounds.