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
Strategies for fine-tuning the catalytic activity of pincer-complexes
Stockholm University, Faculty of Science, Department of Organic Chemistry.
Stockholm University, Faculty of Science, Department of Organic Chemistry.
2006 (English)In: Tetrahedron Letters, ISSN 0040-4039, E-ISSN 1359-8562, Vol. 47, no 50, 8999-9001 p.Article in journal (Refereed) Published
Abstract [en]

Various methoxy substituted pincer-complexes were prepared in order to study the substituent effects on the catalytic activity in palladium catalyzed opening of vinyl epoxides and boronation of cinnamyl alcohol. The results clearly show that methoxy substitution at the para-position of the pincer-complex leads to up to fourfold acceleration of the catalytic reactions, while substitution of the side-arms does not change the activity of the complex or leads to a slight deceleration of the catalytic processes.

Place, publisher, year, edition, pages
2006. Vol. 47, no 50, 8999-9001 p.
Keyword [en]
Pincer-complexes; Catalysis; Substituent effects; Palladium; Boron; Epoxide
Identifiers
URN: urn:nbn:se:su:diva-25750DOI: 10.1016/j.tetlet.2006.08.141OAI: oai:DiVA.org:su-25750DiVA: diva2:200426
Note
Part of urn:nbn:se:su:diva-8524Available from: 2009-02-26 Created: 2009-02-17 Last updated: 2017-12-13Bibliographically approved
In thesis
1. Novel Pincer Complex-Catalyzed Transformations: Including Asymmetric Catalysis
Open this publication in new window or tab >>Novel Pincer Complex-Catalyzed Transformations: Including Asymmetric Catalysis
2009 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

This thesis is focused on the development of new pincer complex-catalyzed transformations. Optimization of the catalytic properties (fine-tuning) was directed to increase the catalytic activity as well as the chemo-, stereo- and enantioselectivity of the complexes. This was achieved by varying the heteroatoms in the terdentate pincer ligand, by changing the electronic properties of the coordinated aryl moiety and by implementing chiral functionalities in the pincer complexes.

In the cross-coupling reaction of vinyl epoxides and aziridines with organoboronic acids the chemoselectivity of the reaction could be increased by employment of pincer complexes instead of commonly used Pd(0) catalysts. Furthermore, the introduction of a methoxy substituent in the aromatic subunit of the complex considerably increased the activity of the pincer complex catalyst.

Fine-tuning of the enantioselectivity in electrophilic allylation reactions was achieved by using a wide variety of new BINOL- and biphenanthrol-based pincer complexes. The highest enantioselectivity (85% ee) was obtained by applying biphenanthrol-based pincer complexes.

Stereoselective pincer complex-catalyzed condensation of sulfonylimines with isocyanoacetate could be achieved under mild reaction conditions. By application of chiral PCP catalysts, 2-imidazolines could be obtained with up to 86% ee.

A new pincer complex-catalyzed C-H bond functionalization based reaction between organonitriles and sulfonylimines affords homoallylic amines and beta-aminonitriles in high yields. The asymmetric version of this process affords beta-aminonitriles with up to 71% ee.

In the last chapter, a pincer complex-catalyzed redox coupling reaction is described. In this highly regio- and stereoselective process the integrity of the pincer catalysts is fully retained. This catalytic reaction proceeds with a high level of functional group tolerance, as allylic acetate and aryl halide functionalities are retained.

Place, publisher, year, edition, pages
Stockholm: Institutionen för organisk kemi, 2009. 136 p.
Keyword
pincer, palladium, catalysis, chiral, asymmetric, palladium IV, allylation, aldol, aminoacid, C-H functionalization, cross-coupling, homoallylic, heck reaction, tridentate ligand
National Category
Chemical Sciences
Research subject
Organic Chemistry
Identifiers
urn:nbn:se:su:diva-8524 (URN)978-91-7155-825-1 (ISBN)
Public defence
2009-03-20, Magnélisalen, Kemiska övningslaboratoriet, Svante Arrhenius väg 12 A, Stockholm, 10:00 (English)
Opponent
Supervisors
Available from: 2009-02-26 Created: 2009-02-17 Last updated: 2009-05-25Bibliographically approved
2. Catalytic Functionalization of Allylic Substrates by Palladium Pincer Complexes
Open this publication in new window or tab >>Catalytic Functionalization of Allylic Substrates by Palladium Pincer Complexes
2010 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

This thesis is based on the development of novel catalytic reactions for the synthesis and application of organometallic reagents. The main focus is directed towards organoboronate derivatives. We developed an efficient procedure for converting allylic alcohols to the corresponding allylboronates using palladium pincer complexes as catalysts. The reactions were performed under mild conditions with high selectivity, allowing further one-pot transformations. Using this approach, a variety of stereodefined homoallylic alcohols and amino acid derivatives were synthesized via trapping of the in situ generated allylboronate derivatives with an appropriate electrophile. The synthetic scope of these types of multi-component reactions is broad as many different substrate allylic alcohols may be used together with various electrophiles. Several aspects of these reactions were studied, including different reagents, catalysts and electrophiles.

Furthermore, we studied the possibility to use oxidizing reagents as an essential component in the functionalization of olefins. Two main strategies were utilized for these catalytic methods using palladium pincer complexes. The functional group was either transferred from the oxidizing reagent, or introduced via an oxidation-transmetallation route. We propose that both methods involve palladium(IV) intermediates thus expanding both the coordination sphere of palladium and the synthetic scope of pincer complex catalysis.

Place, publisher, year, edition, pages
Stockholm: Department of Organic Chemistry, Stockholm University, 2010. 65 p.
Keyword
Catalysis, Palladium, Pincer Complex, Boron, Multicomponent Reaction
National Category
Organic Chemistry
Research subject
Organic Chemistry
Identifiers
urn:nbn:se:su:diva-39065 (URN)978-91-7447-090-1 (ISBN)
Public defence
2010-06-22, Magnélisalen, Kemiska övningslaboratoriet, Svante Arrhenius väg 16 B, Stockholm, 13:00 (English)
Opponent
Supervisors
Note
At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 11: In press.Available from: 2010-05-24 Created: 2010-05-06 Last updated: 2010-05-21Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full text

Search in DiVA

By author/editor
Selander, NicklasSzabó, Kálmán J.
By organisation
Department of Organic Chemistry
In the same journal
Tetrahedron Letters

Search outside of DiVA

GoogleGoogle Scholar

doi
urn-nbn

Altmetric score

doi
urn-nbn
Total: 80 hits
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