One-step synthesis of substituted dihydro- and tetrahydroisoquinolines by FeCl3.6H2O 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.