SYNTHESES OF QUINOLIZIDINONE AND INDOLIZIDINONE USING N-ACYLIMINIUM ION CYCLIZATION AND A ONE-POT PROCEDURE FOR PREPARATION OF BENZOQUINOLIZIDINONE

摘要

Quinolizidinone, and indolizidinone systems were synthesized in a non-racemic form using cyclization of chiral N-acyliminium ions. The key reactive intermediates were prepared from the corresponding 2-arylethylamine or 3-butenylamine and L-glutamic acid or L-aspartic acid. The stereocenter bearing a dibenzylamino group was used for stereocontrol and resulted in diastereomeric products. A one-pot procedure for synthesis of benzoquinolizidinone was also developed. The dibenzylamino moiety was subsequently converted via Cope elimination to the corresponding cyclic enamide which is suitable as a synthetic precursor for a variety of quinolizidine alkaloids in enantiomerically pure form.