Copper/silver-cocatalyzed Conia-ene reaction of linear β-alkynic β-ketoesters

A novel and general copper/silver catalytic system has been developed for the Conia-ene intramolecular reaction of linear beta-alkynic beta-ketoesters. In the presence of (CuOTf)(2)center dot C6H6 and AgSbF6 (or AgOAc), a variety of the linear 6-alkynic 6-ketoesters selectively underwent the Conia-ene intramolecular reaction in moderate to good yields.