Organocatalytic Enantioselective Synthesis of Dihydronaphthofurans and Dihydrobenzofurans: Reaction Development and Insights into Stereoselectivity & Design and Synthesis of Heterogeneous Recyclable Organocatalysts

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Zeynep Dilşad Susam Tez.pdf

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2022-11-18

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SUSAM, Zeynep Dilşad

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The first part of thesis comprises Friedel-Crafts/substitution, which is the most common and widely used C-C bond forming reaction in synthetic organic chemistry. Applications of these reactions in domino type reactions are trending topic in organocatalytic studies in the recent years. These types of reactions are used to perform dihydrobenzofuran (DHB) and dihydronaphthofuran (DHN) skeletons, which are very important pharmaceutical precursors. In this study, it was chosen as the key step in domino reaction to afford disubstituted dihydronaphthofuran derivatives possessing two chiral centers in enantiomerically enriched form. For this purpose, (Z)-(2-bromo-2-nitrovinyl) benzene and β–naphthol was used to perform model organocatalytic Friedel-Crafts/substitution domino type reaction. In this part, 65 different chiral DHN and DHB derivatives were synthesized with quinine based novel bifunctional organocatalyst, which has been developed in our group, in up to >99% ee under the optimized condition with 5 mol% catalyst loading. In the second part of the study, a similar Friedel-Crafts domino approach was also applied to synthesize 2,3-dihydrofuran derivatives. 11 different DHF derivatives were synthesized in up to 95% ee with complete conversion. In the third part of the study, novel heterogeneous catalysts are constructed from our homogeneous catalysts. For this purpose, initial trials with the small amount of catalyst have started to generate the active site for the attachment to gold nanoparticles. The attachment of the catalysts to the gold surfaces were also performed. After other characterization studies of these catalysts will be completed and they will be ready to be tested in different type of asymmetric reactions.

Subject Keywords

Organocatalyst, Enantioselectivity, Friedel-Crafts, Domino, Recyclable Heterogeneous Catalyst

URI

https://hdl.handle.net/11511/101225

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Graduate School of Natural and Applied Sciences, Thesis

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Citation Formats

Z. D. SUSAM, “Organocatalytic Enantioselective Synthesis of Dihydronaphthofurans and Dihydrobenzofurans: Reaction Development and Insights into Stereoselectivity & Design and Synthesis of Heterogeneous Recyclable Organocatalysts,” Ph.D. - Doctoral Program, Middle East Technical University, 2022.