Lambin, Dominique
[UCL]
(eng)
One considerable issue in organic chemistry nowadays is the taming of chirality. In this context, asymmetric catalysis represents a powerful and economical method to generate chirality in a controlled maner. Furthermore, the underlying biological, environmental and economical issues continuously stimulate the improvement of existing methods and fuel the search for new research fields and new concepts. The recent merging of supramolecular chemistry and asymmetric catalysis has for instance afforded a new research field, namely supramolecular catalysis, research field to which our own research projects will be related.
The first part of this thesis was devoted to the development of a new way to generate bidentate ligands and to their further use in asymmetric catalysis. These bidentate ligands would be synthetised from two ditopic ligands, by means of a self assembly process based on coordination interactions.
Synthetic efforts towards some appropriate ditopic ligands were firstly made. The viability of the self-assembly step was then assessed. Unfortunately, a lack of orthogonality between the different coordination interactions within the system was observed, underlying some inherent drawbacks of the initially proposed self-assembly system.
Trying to take advantage of theses limitations then guided us towards a second research project.
This second part was devoted to the study of new copper complexes of general strucure [(N1N2)Cu(L1L2)]+X-, ultimately aiming at the development of a copper (I) catalytic system onto N1N2 imines substrates.. Depending on the nature of ligands L1 and L2, and the nature of anion X-, complexes successively achiral, chiral-at-metal racemic, and finally complexes existing as diastereoisomeric ions pairs were studied.
Efficient synthetic methods were designed for each of theses complexes classes. Detailled studies then allowed the description and understanding of the inherent equilibria within these copper (I) complexes. The copper atom stereogenicity could be observed in specific cases, leading to the first description of tetracoordinated copper complexes exhibiting a central at metal-chirality.
Finally, first exploratory efforts were made towards the development of an enantioselective addition reaction of organometallic derivatives on imines substrates, catalyzed by copper complexes bearing a chiral anion.
Référence bibliographique |
Lambin, Dominique. Approches supramoléculaires pour la catalyse énantiosélective. Prom. : Riant, Olivier |
Permalien |
http://hdl.handle.net/2078.1/68559 |