Bispidine derivatives as molecular tools for studies of (-Allyl)palladium complexes: Ligand synthesis and analythical cpplications
1998 (English)Doctoral thesis, comprehensive summary (Other academic)
Determination of structural and stereochemical features of reaction intermediates in transition metal catalysed reactions is of central interest. Bispidine derivatives as ligands in (π-allyl)palladium complexes in combination with 1H NMR spectroscopy are shown to be useful tools for revealing structural characteristics of these reaction intermediates. As a support for the conclusions drawn from NMR investigations, X-ray crystallography and calculated structures were used.
Complexes of bispidine derivatives with varying substitution pattern and different pre-formed bis[(η3-allyl)palladium chloride] complexes were formed. The resulting complexes were analysed with 1H NMR spectroscopy, especially regarding the inter-ligand NOEs and the chemical shift effects due to anisotropic effects. It is shown that a large steric interaction between the aromatic systems of N,N'-diphenylated bispidine derivatives and various (π-allyl)palladium systems can be obtained. This steric interaction can be used for hindering rotation around C-C single bonds in (π-allyl)palladium ligands.
Furthermore, the nearness of the aromatic systems and the (π-allyl)palladium ligand give rise to anisotropic effects that, after quantification, can give information about the structure in such complexes. The inter-ligand NOEs can, in the case of a N,N-diphenyl substituted bispidine derivative, be used for assignment of relative configuration in a set of acyclic (π-allyl)palladium ligands. With a bispidine derivative carrying chiral substituents, the inter-ligand NOEs were used for assignment of absolute configuration of (π-allyl)palladium ligands.
Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis , 1998. , 43 p.
Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1104-232X ; 375
Research subject Organic Chemistry
IdentifiersURN: urn:nbn:se:uu:diva-895ISBN: 91-554-4248-XOAI: oai:DiVA.org:uu-895DiVA: diva2:172248
1998-09-25, Svedberg lecture hall at the Institute of Chemistry, Uppsala University, Uppsala, 10:15