Synthesis and Design of Foldamers for Organocatalysis

Details

Supervisors

Singleton, Michael L.

Faculty

Faculté des sciences

Degree label

Master [120] en sciences chimiques, à finalité spécialisée: chimie de l'industrie

Abstract

Enzymes and organocatalysts have been extensively used to catalyze a wide range of reactions in chemistry. Despite their numerous advantages, those two types of catalysts also present some drawbacks that would be interesting to overcome. In this regard, foldamers seem to combine the best of both worlds by only carrying relevant groups on a well-defined backbone, similar to the folding of enzymes, which is easily tunable. Foldamers present many other advantages such as the ease of synthesis and the predictability of the resulting structure based on different interactions between the monomers in the sequence. While aliphatic foldamers have been used several times as organocatalysts, there exist however, very few examples of aromatic foldamers, and more precisely, aromatic oligoamide foldamers used for such purpose. Therefore, we aimed at synthetizing an aromatic oligoamide foldamer for organocatalysis. In this master’s thesis we describe the synthesis of a new helical aromatic oligoamide foldamer containing the repeating quinoline-pyridine-quinoline unit leading to the alignment of isobutoxy side chains on two faces of the helix. The helical structure resulting from π-stacking, hydrogen bonds and electrostatic interactions was confirmed in the solid and the solution states. This master’s thesis also describes the different attempts for the second purpose of the project, being the synthesis of quinolines units functionalized with different urea groups. From the two targeted amine precursors, only the 4-aminoquinoline was successfully obtained but no urea derivatives could be synthesized. We describe the different approaches using isocyanate derivatives. We describe herein the attempts for the synthesis of a second amine group, an aminopropoxy quinoline which could not be deprotected and therefore could not be used in reactions with isocyanate derivatives.