[摘要]:We report here the construction of quinolizidine ring systems by intramolecular cyclization of suitable functionalized pipendines via a reductive amination sequence This reaction proceeds with a total stereocontrol at C4 The preparation of the piperidine precursors is based on a chain elongation of a piperidine aldehyde either by aldolization or by Wittig reaction We applied this second route to the total synthesis of quinolizidine (-)-217A from (S)-methyl 2-((S)-1-((R)-1-phenylethyl)pipendin-2-yl)propanoate 5 |