General Zinc-Catalyzed Conia-Ene Reactions of 1,3-Dicarbonyl Compounds with Alkynes Including the Classically Challenging Substrates under Neat Conditions

A simple, versatile new approach to four-membered ring to six-membered ring products has been developed by zinc-catalyzed intramolecular Conia-ene reactions of 1,3-dicarbonyl compounds with alkynes. This new route allows a wide range of dicarbonyl compounds, including the classically challenging 1,3-diesters and N,N'-disubstituted 1,3-keto amides, to be used for the Conia-ene reaction with inexpensive zinc chloride (ZnCl2) under neat conditions.