Copper/Silver-Cocatalyzed Conia-Ene Reactions of 2-Alkynic 1,3-Dicarbonyl Compounds

A copper/silver-catalyzed Conia-ene reaction has been developed for selectively constructing five-membered and six-membered rings. In the presence of (CuOTf)(2)center dot C6H6 and AgBF4, a variety of 2-alkynic 1,3-dicarbonyl compounds underwent the Conia-ene intramolecular reaction smoothly in moderate to good yields. It is noteworthy that both 2-phenylacetylhept-6-ynenitrile and diethyl 2-(pent-4-ynyl)-malonate are also suitable substrates under the standard conditions, and the selectivity toward endo- or exo-products depends on the substitutents at the terminal of alkynes.