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Atropoisomerism in Phosphepines and Azepines
KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry. (Christina Moberg)
KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry. (Zoltán Szabó)ORCID iD: 0000-0002-7552-1076
KTH, School of Chemical Science and Engineering (CHE), Chemistry, Organic Chemistry. (Christina Moberg)ORCID iD: 0000-0002-1743-7650
2009 (English)In: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 74, no 23, 9120-9125 p.Article in journal (Refereed) Published
Abstract [en]

Free energy barriers to biaryl tropoinversion in metal complexes with tropos phosphepine and azepine ligands were determined by temperature-dependent P-31 NMR inversion-transfer experiments and line shape analysis of the temperature-dependent H-1 NMR spectra, respectively. The barrier in the PdCl2 complex of the azepine ligand was found to be slightly higher than that of the corresponding free ligand. Studies of a tridentate azepine ligand Suggested that Configurational change takes place without prior decoordination from the metal.

Place, publisher, year, edition, pages
Washington DC: American Chemical Society , 2009. Vol. 74, no 23, 9120-9125 p.
Keyword [en]
atropoisomerism, phosphepines, azepines, palladium, rotation barrier, VT NMR, inversion transfer, line shape analysis
National Category
Organic Chemistry
Identifiers
URN: urn:nbn:se:kth:diva-12847DOI: 10.1021/jo902047kISI: 000272083700023Scopus ID: 2-s2.0-72249106390OAI: oai:DiVA.org:kth-12847DiVA: diva2:319274
Note
QC20100630Available from: 2010-05-17 Created: 2010-05-17 Last updated: 2017-12-12Bibliographically approved
In thesis
1. Self-adaptable catalysts: Importance of flexibility and applications in asymmetric catalysis
Open this publication in new window or tab >>Self-adaptable catalysts: Importance of flexibility and applications in asymmetric catalysis
2010 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

The topic of this thesis is the design and synthesis of biaryl-based self adaptableligands for asymmetric metal catalysis. The results discussed in papers I-III are covered, together with some unpublished results concerning substrate-adaptable catalysts. A general survey of self-adaptable catalysts is presented first.

The second chapter of this thesis starts with a survey of inversion barriers in biphenyl-based ligands and catalysts. Thereafter, the determination of barriers to conformational adaptation in dibenzoazepines and dibenzophosphepines is described. Palladium complexes with a diphosphine ligand or a diamine ligand, as well as the free diamine ligand, were studied. Entropies and enthalpies of activation were determined with variable temperature NMR spectroscopy. The mechanism of conformational change in the metal complexes was elucidated.

The third chapter describes the synthesis of semiflexible and rigid phosphinite ligands, as well as their application in rhodium-catalysed asymmetric hydrogenation. Modest enantioselectivities (up to 63% ee) were obtained. The semiflexible ligand was found to behave like the most active rigid diastereomer. The fourth chapter describes the behaviour of amine and phosphoramidite ligands in model complexes relevant to the palladium-catalysed asymmetricallylic alkylation of benchmark substrates. Diphosphoramidite and aminephosphoramiditeligands were designed and synthesised. Pd(olefin) complexesof diamine and diphosphoramidite ligands were studied, and their symmetry determined. It was found that both types of ligands are able to adapt their conformation to the substrate.

Place, publisher, year, edition, pages
Stockholm: KTH, 2010. 58 p.
Series
Trita-CHE-Report, ISSN 1654-1081 ; 2010:19
Keyword
adaptable, flexible, semi-flexible, symmetry, conformational study, mechanistic study, rotation barrier, VT NMR, asymmetric catalysis, ligand design, allylic alkylation, hydrogenation, azepines, dioxaphosphepines, phosphepines, amines, phosphines, phosphoramidites, phosphinites, palladium, rhodium
National Category
Organic Chemistry
Identifiers
urn:nbn:se:kth:diva-12852 (URN)978-91-7415-645-4 (ISBN)
Public defence
2010-06-09, F3, Lindstedtsvägen 26, Stockholm, 10:00 (English)
Opponent
Supervisors
Note
QC20100630Available from: 2010-05-21 Created: 2010-05-17 Last updated: 2010-06-30Bibliographically approved

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Szabó, ZoltánMoberg, Christina

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