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dc.contributor.authorHöck, Stefan-
dc.contributor.authorBorschberg, Hans-Jürg-
dc.date.accessioned2018-10-19T14:26:33Z-
dc.date.available2018-10-19T14:26:33Z-
dc.date.issued2003-
dc.identifier.issn0018-019Xde_CH
dc.identifier.issn1522-2675de_CH
dc.identifier.urihttps://digitalcollection.zhaw.ch/handle/11475/11997-
dc.description.abstractSignificant improvements in the realm of a recently disclosed, novel synthetic concept towards the Iboga alkaloid family are presented. The key step for the construction of the bicyclic aliphatic core consists of an intramolecular nitrone-olefin 1,3‐dipolar cycloaddition reaction of a 1 : 1 mixture 15/16 yielding the two diastereoisomeric tricyclic isoxazolidine derivatives 17 and 18. The required nitrones were prepared from the readily available (S)‐hydroxylactone 6 in twelve steps with an overall yield of 15% (average: 83.5% per step). The relative configuration of the minor isomer was deduced unambiguously by single‐crystal X‐ray analysis of the derived tricyclic carbamate 21. As four out of five asymmetric centers in the pair 17/18 have opposite configuration, destruction of the one possessing the same absolute configuration transforms the original set of diastereoisomers into a pair of enantiomers. We verified this contention by oxidizing the two alcohols 20 and 22 to yield the two antipodal forms of ketone 23. The absence of significant amounts of by‐product and the high reproducibility of the crucial cycloaddition reaction represent marked improvements over our earlier attempts. In addition, the new route, which starts from L‐glutamate, should provide access to both naturally occurring antipodal series of the targeted alkaloid class.de_CH
dc.language.isoende_CH
dc.publisherWileyde_CH
dc.relation.ispartofHelvetica Chimica Actade_CH
dc.rightsLicence according to publishing contractde_CH
dc.subjectIndole Alkaloidsde_CH
dc.subjectEnantioselektive Synthesisde_CH
dc.subjectIreland-Claisen Rearrangemenentde_CH
dc.subject.ddc540: Chemiede_CH
dc.titleEnantioselective synthesis of key intermediates in a novel approach towards the Iboga-alkaloid familyde_CH
dc.typeBeitrag in wissenschaftlicher Zeitschriftde_CH
dcterms.typeTextde_CH
zhaw.departementLife Sciences und Facility Managementde_CH
zhaw.organisationalunitInstitut für Chemie und Biotechnologie (ICBT)de_CH
dc.identifier.doi10.1002/hlca.200390125de_CH
zhaw.funding.euNode_CH
zhaw.issue5de_CH
zhaw.originated.zhawNode_CH
zhaw.pages.end1409de_CH
zhaw.pages.start1397de_CH
zhaw.publication.statuspublishedVersionde_CH
zhaw.volume86de_CH
zhaw.publication.reviewPeer review (Publikation)de_CH
Appears in collections:Publikationen Life Sciences und Facility Management

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Höck, S., & Borschberg, H.-J. (2003). Enantioselective synthesis of key intermediates in a novel approach towards the Iboga-alkaloid family. Helvetica Chimica Acta, 86(5), 1397–1409. https://doi.org/10.1002/hlca.200390125
Höck, S. and Borschberg, H.-J. (2003) ‘Enantioselective synthesis of key intermediates in a novel approach towards the Iboga-alkaloid family’, Helvetica Chimica Acta, 86(5), pp. 1397–1409. Available at: https://doi.org/10.1002/hlca.200390125.
S. Höck and H.-J. Borschberg, “Enantioselective synthesis of key intermediates in a novel approach towards the Iboga-alkaloid family,” Helvetica Chimica Acta, vol. 86, no. 5, pp. 1397–1409, 2003, doi: 10.1002/hlca.200390125.
HÖCK, Stefan und Hans-Jürg BORSCHBERG, 2003. Enantioselective synthesis of key intermediates in a novel approach towards the Iboga-alkaloid family. Helvetica Chimica Acta. 2003. Bd. 86, Nr. 5, S. 1397–1409. DOI 10.1002/hlca.200390125
Höck, Stefan, and Hans-Jürg Borschberg. 2003. “Enantioselective Synthesis of Key Intermediates in a Novel Approach towards the Iboga-Alkaloid Family.” Helvetica Chimica Acta 86 (5): 1397–1409. https://doi.org/10.1002/hlca.200390125.
Höck, Stefan, and Hans-Jürg Borschberg. “Enantioselective Synthesis of Key Intermediates in a Novel Approach towards the Iboga-Alkaloid Family.” Helvetica Chimica Acta, vol. 86, no. 5, 2003, pp. 1397–409, https://doi.org/10.1002/hlca.200390125.


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