Design, synthesis and testing of new chiral sulfide catalysts for Corey-Chaykovsky reaction
1University of Oulu, Faculty of Science, Department of Chemistry
|Online Access:||PDF Full Text (PDF, 1.4 MB)|
|Persistent link:|| http://urn.fi/urn:isbn:9514265718
|Publish Date:|| 2001-11-19
|Thesis type:||Doctoral Dissertation
|Defence Note:||Academic Dissertation to be presented with the assent of the Faculty of Science, University of Oulu, for public discussion in Raahensali (Auditorium L10), Linnanmaa, on December 5th, 2001, at 12 noon.
Professor Tapio Hase
Professor Liisa Kanerva
The first part of this monograph discusses the asymmetric, ylide based, reagent controlled epoxidations. Both different chiral ylides and epoxidation processes, stoichiometric and catalytic, are reviewed.
In the following part, new chiral sulfide catalysts were discovered as enantioselective catalysts for the Corey-Chaykovsky reaction (epoxidation of aldehydes via sulfonium ylides). Using a crystal structure of an oxazolidine derivative as a starting point, a thiazolidine ligand family was designed, synthesized and finally employed as catalysts in the asymmetric epoxidation of benzaldehyde. The ligands were prepared starting from L-valine, L-tert-leucine, D-penicillamine and L-cysteine. The differently tuned thiazolidine ligands were demonstrated to catalyze the formation of trans-stilbene oxide with varying enantioselectivities. On the basis of these results, a mechanistic rationale for the asymmetric induction was presented. The results heavily demonstrated the importance of ring rigidity as an affecting factor in the enantioselectivity of the tested thiazolidines.
Acta Universitatis Ouluensis. A, Scientiae rerum naturalium
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