One-Step Synthesis of Substituted Dihydro- and Tetrahydroisoquinolines by FeCl<sub>3</sub>·6H<sub>2</sub>O Catalyzed Intramolecular Friedel−Crafts Reaction of Benzylamino-Substituted Propargylic Alcohols
A mild, versatile, and efficient method for the one-step synthesis of substituted dihydro- and tetrahydroisoquinolines has been developed by the FeCl3·6H2O catalyzed intramolecular allenylation/cyclization reaction of benzylamino-substituted propargylic alcohols, representing the first example of the intramolecular Friedel−Crafts reaction of propargylic alcohols.