One-step synthesis of substituted dihydro- and tetrahydroisoquinolines by Fe[Cl.sub.3].6[H.sub.2]O catalyzed intramolecular Friedel-Crafts reaction of benzylamino-substituted propargylic alcohols

A versatile and efficient method is described for the one-step synthesis of substituted dihydro- and tetrahydroisoquinolines. This method is developed by the Fe[Cl.sub.3].6[H.sub.2]O catalyzed intramolecular allenylation/cyclization reaction of benzylamino-substituted propargylic alcohols, which has represented the first example of the intramolecular Fieldel-Crafts reaction of propargylic alcohols.