Efficient stereoselective syntheses of piperidine, pyrrolidine,
and indolizidine alkaloids*
Dieter Enders** and Christoph Thiebes
Institut für Organische Chemie, Rheinisch-Westfälische
Technische Hochschule, Professor-Pirlet-Strasse 1, 52074 Aachen, Germany
Abstract: Recent advances in the diastereo- and enantioselective
synthesis of piperidine, pyrrolidine, and indolizidine alkaloids, based
on the highly stereoselective 1,2-addition to the CN double bond of
chiral aldehyde-SAMP/RAMP hydrazones, are described. The enantioselective
syntheses of the pyrrolidine alkaloids bgugaine and (2S,12¢R)-2-(12¢-aminotridecyl)-pyrrolidine,
a defense alkaloid of the Mexican bean beetle are reported. Furthermore,
the SAMP/RAMP-hydrazone method was applied to the syntheses of two 5,8-disubstituted
indolizidine alkaloids that have been extracted from neotropical poison-dart
frogs. The a-alkylation of aldehyde-SAMP/RAMP hydrazones has been used
in the enantioselective synthesis of two epimers of stenusine, a 3-substituted
piperidine alkaloid and spreading reagent of the beetle Stenus comma.
*Lecture presented at the 22nd IUPAC International
Symposium on the Chemistry of Natural Products, São Carlos, Brazil,
3-8 September 2000. Other presentations are published in this issue,
pp. 549-626.
**Corresponding author
