Rhenium-Catalyzed Insertion of Terminal Acetylenes into a C−H Bond of Active Methylene Compounds

reaction: see text A rhenium complex, ReBr(CO)(3)(thf)(2), catalyzed the intermolecular reactions of 1,3-dicarbonyl compounds with terminal acetylenes and gave the corresponding alkenyl derivatives in excellent yields. These reactions could apply to an intramolecular version and gave the corresponding cyclic compounds quantitatively.