Enantioselective total syntheses of the alkaloids (−)-rhazinal, (−)-rhazinilam, (−)-leuconolam and (+)- epi -leuconolam

Abstract

The title alkaloids, (-)-1, (-)-2, (-)-4 and (+)-5 respectively, have each been prepared from the enantiomerically enriched (74% ee) tetrahydroindolizine 14 which is itself obtained via an organocatalyzed and enantioselective intramolecular Michael addition reaction of the pyrrole 13 incorporating an N-tethered and β,β-disubstituted acrylaldehyde moiety.