Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Asymmetric Hydrogenation of Functionalized Olefins Using N,P-Ligated Iridium Complexes
Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Synthetical Organic Chemistry.
2012 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Transition-metal-catalyzed asymmetric hydrogenation is one of the most efficient, straightforward, and well-established methods for preparing enantiomerically enriched compounds. Over the past decades, significant progress has been made with iridium, rhodium and ruthenium complexes to asymmetric hydrogenate a selection of olefins, such as, α,β-unsaturated carboxylic acid derivatives, ketones, imines and phosphonates. Although these metals have been applied successfully in the hydrogenation of olefins, they differ in their substrate tolerance.  Ruthenium and rhodium based catalysts require a coordinating group in the vicinity of the C=C bond. However, iridium based catalysts do not require this coordinating group, hence, asymmetric hydrogenation with iridium catalysts has been widely used for both functionalized and unfunctionalized olefin substrates. This thesis focuses on expanding the substrate scope for asymmetric hydrogenation using chiral N,P-ligated iridium catalysts. Papers I and II investigate the asymmetric hydrogenation of prochiral N-heterocyclic compounds prepared by ring-closing metathesis using the iridium catalysts developed in our group.  These substrates are interesting as they bear resemblance to pharmaceutically active compounds and therefore have tremendous value in medicinal chemistry.  Excellent enantioselectivities, up to >99% ee and conversions were obtained. In papers III and IV we synthesized many unsaturated acyclic and cyclic sulfones with varying substitution patterns.  The sulfones were subjected to hydrogenation using our N,P-ligated iridium catalysts, producing the chiral sulfone products in high enantiomeric excess (up to 99% ee). This methodology was combined with the Ramberg-Bäcklund reaction, offering a novel route to chiral allylic and homoallylic compounds. In addition to obtaining these chiral compounds in good yields, no decrease in enantiomeric excess was observed after the Ramberg-Bäcklund reaction. This strategy has been applied in the preparation of the chiral building block for renin inhibitors.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2012. , 59 p.
Series
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 983
Keyword [en]
asymmetric hydrogenation, iridium, Ramberg-Bäcklund reaction, sulfone, heterocycle, preclamol, remikiren
National Category
Organic Chemistry
Identifiers
URN: urn:nbn:se:uu:diva-182648ISBN: 978-91-554-8503-0 (print)OAI: oai:DiVA.org:uu-182648DiVA: diva2:561043
Public defence
2012-11-29, A1:107A, BMC, Husargatan 3, Uppsala, 10:15 (English)
Opponent
Supervisors
Available from: 2012-11-07 Created: 2012-10-14 Last updated: 2013-01-23
List of papers
1. Highly Flexible Synthesis of Chiral Azacycles via Iridium-Catalyzed Hydrogenation
Open this publication in new window or tab >>Highly Flexible Synthesis of Chiral Azacycles via Iridium-Catalyzed Hydrogenation
Show others...
2010 (English)In: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 132, no 26, 8880-8881 p.Article in journal (Refereed) Published
Abstract [en]

A range of saturated chiral azacycles has been prepared in high yield and with high selectivity from simple starting materials. A modular approach with ring-closing metathesis as a key step was used to produce a number of five-, six-, and seven-membered cyclic alkenes. Asymmetric hydrogenation catalyzed by N,P-ligated iridium complexes gave saturated azacycles in high optical purity. This methodology was demonstrated in the synthesis of a pharmaceutical precursor.

National Category
Chemical Sciences
Identifiers
urn:nbn:se:uu:diva-135809 (URN)10.1021/ja103901e (DOI)000279561200033 ()20557052 (PubMedID)
Available from: 2010-12-09 Created: 2010-12-08 Last updated: 2017-12-11Bibliographically approved
2. Chiral Hetero- and Carbocyclic Compounds from the Asymmetric Hydrogenation of Cyclic Alkenes
Open this publication in new window or tab >>Chiral Hetero- and Carbocyclic Compounds from the Asymmetric Hydrogenation of Cyclic Alkenes
Show others...
2012 (English)In: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 18, no 21, 6507-6513 p.Article in journal (Refereed) Published
Abstract [en]

Several types of chiral hetero- and carbocyclic compounds have been synthesized by using the asymmetric hydrogenation of cyclic alkenes. N,P-Ligated iridium catalysts reduced six-membered cyclic alkenes with various substituents and heterofunctionality in good to excellent enantioselectivity, whereas the reduction of five-membered cyclic alkenes was generally less selective, giving modest enantiomeric excesses. The stereoselectivity of the hydrogenation depended more strongly on the substrate structure for the five- rather than the six-membered cyclic alkenes. The major enantiomer formed in the reduction of six-membered alkenes could be predicted from a selectivity model and isomeric alkenes had complementary enantioselectivity, giving opposite optical isomers upon hydrogenation. The utility of the reaction was demonstrated by using it as a key step in the preparation of chiral 1,3-cis-cyclohexane carboxylates.

Keyword
asymmetric synthesis, heterocyclic compounds, homogeneous catalysis, hydrogenation, iridium
National Category
Chemical Sciences
Identifiers
urn:nbn:se:uu:diva-175620 (URN)10.1002/chem.201104073 (DOI)000304045000016 ()
Available from: 2012-06-12 Created: 2012-06-11 Last updated: 2017-12-07Bibliographically approved
3.
The record could not be found. The reason may be that the record is no longer available or you may have typed in a wrong id in the address field.
4.
The record could not be found. The reason may be that the record is no longer available or you may have typed in a wrong id in the address field.

Open Access in DiVA

fulltext(7329 kB)