Diverse Asymmetric Quinolizidine Synthesis: A Stereodivergent One-Pot Approach
2010 (English)In: Advanced Synthesis and Catalysis, ISSN 1615-4150, E-ISSN 1615-4169, Vol. 352, no 2-3, 499-518 p.Article in journal (Refereed) Published
A diverse stereodivergent organocatalytic one-pot addition/cyclization/annulation sequence to optically active quinolizidine derivatives from easily available starting materials is presented. The one-pot sequence relies on a pyrrolidine-catalyzed enantioselective Conjugate addition of electron-deficient amide alpha-carbons to alpha,beta-unsaturated aldehydes, spontaneous hemiaminal formation and acid-catalyzed/mediated N-acyliminium ion cyclization to give the quinolizidine framework. Simple tuning of the reaction conditions in the N-acyliminuim ion cyclization step provides a diastereomeric switch, which gives access to both of the two bridgehead epimers through kinetic, thermodynamic or chelation control. The methodology display a broad substrate scope that is demonstrated by the stereoselective formation of indolo-, thieno-, benzofuro-, furo- and different benzoquinolizidine derivatives with high atom efficiency, up to >99% ee and up to >95:5 dr. Due to its efficiency, synthetic diversity and operational simplicity, this protocol has the potential to find important use as a key step in natural product Synthesis, biochemistry and pharmaceutical science. The stereochemical Outcome of the one-pot sequence was investigated. and the mechanism and origin of stereoselectivity of the different steps is discussed.
Place, publisher, year, edition, pages
2010. Vol. 352, no 2-3, 499-518 p.
N-acyliminuim ion cyclization, alkaloids, one-pot reaction, organocatalysis, quinolizidines, stereodivergent synthesis
IdentifiersURN: urn:nbn:se:kth:diva-19285DOI: 10.1002/adsc.200900686ISI: 000275235800033ScopusID: 2-s2.0-77349124192OAI: oai:DiVA.org:kth-19285DiVA: diva2:337332
FunderSwedish Research Council
QC 20100525 QC 201202242010-08-052010-08-052012-02-24Bibliographically approved