Gold(I)-Catalyzed Intramolecular Tandem Addition/Friedel−Crafts Reactions between Acyclic Enamides and 1-Arylalkynes

Electron-deficient acyclic enamine derivatives react with electron-rich 1-arylalkynes using cationic gold(I) species as catalysts in an intramolecular process to form annulated 1-amido-substituted indene derivatives as the major products. Yields for this process range between 21% and 98%. In some cases, a two-step process that includes a subsequent alkene isomerization is needed.