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) x C(6)H(6) and AgBF(4), 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 substituents at the terminal of alkynes.