Stereospecific synthesis of tetrahydrobenzisoquinoline derivatives

Abstract

A new synthesis of optically active tetrahydrobenzisoquinolines is described. Cyclization of N-aryl- alkylalanines with retention of configuration was achieved by mild intramolecular Friedel-Crafts acylation. The compounds synthesized this way represent simple analogues of phenanthroindolizidine alkaloids. Some features of the n.m.r. spectra of cyclized and open-chain intermediates are discussed.