A short, enantioselective synthesis of (-)-epilupinine from proline via a spirocyclic ammonium ylide

Article abstract of DOI:10.1016/S0040-4020(97)01037-5

Diazoketone 5b, available in one step from proline benzyl ester, underwent conversion to quinolizidine 8b with high diastereoselectivity (19:1 8b/7b) and in surprisingly high enantiomeric excess (75%). The key step presumably occurs via spirocyclic ylide