Polymer supported and homogeneous organocatalysts for asymetric reactions: from batch to continuous flow applications

Identifier:  TDX:1433

Handle: https://hdl.handle.net/20.500.11797/TDX1433

Authors:  Kasaplar Ozkal, Pinar

Abstract:
The general aim of this thesis is to establish a synthetic route for the immobilization of organocatalysts onto polymer support. In this work, firstly we describe the development of polystyrene-supported diarylprolinol ethers via copper-catalyzed azide alkyne cycloaddition reaction, additionally, homogeneous proline derived thiourea organocatalyst and finally, polystyrene supported hydrogen bonding squaramide and thiourea organocatalysts. The formation and application of PS-supported diarylprolinol ethers was demonstrated successfully in Michael-type reactions. Then we continued with H-bonding homogeneous organocatalysts, proline derived bifunctional thiourea organocatalysts tested in enantioselective anti-Mannich reactions. In the last part, a facile preparation of PS-supported squaramide organocatalyst was successfully demonstrated, high catalytic activities and enantioselectivities obtained in the Michael addition reactions. Furthermore, all the advantages of solid supported catalysts such as recycling, and continuous flow applications have been performed with success. At the same time, the PS-supported thiourea organocatalyst was prepared with an approach adapted from the synthesis of squaramide organocatalyst. This thiourea was used in the α-amination reaction together with squaramide organocatalyst, good to moderate results were obtained in the α-hydrazination of 1,3-dicarbonyl compounds. Therefore, we have been able to develop effective polymer-supported organocatalysts and used them in the recycling and continuous flow applications successfully.