TBAF-Catalyzed O-Nucleophilic Cyclization of Enaminones: A Process for the Synthesis of Dihydroisobenzofuran Derivatives

A novel methodology for the stereoselective synthesis of dihydroisobenzofuran derivatives is described in this paper. The procedure was realized by the bifunctional TBAF catalyzed selective O-nucleophilic cyclization of enaminone with intramolecular alkyne under mild and non-metal-mediated conditions. The results of control experiments suggested that the cation-pi interaction and basicity, offered by TBAF, might be indispensable for the isomerization of enaminone and the formation of carbon-oxygen bond.