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Application of amines for the preparation of chiral cyclic compounds
Formánek, Bedřich ; Veselý, Jan (advisor) ; Kočovský, Pavel (referee) ; Soural, Miroslav (referee)
Organocatalysis, along with catalysis by metal complexes or enzymes, has become one of the very useful tools of asymmetric synthesis. Different activation modes or their combinations into sequences (domino reactions) enable effective access to enantiomerically enriched complex substances. The objective of this work was the preparation of chiral molecules from simple precursors activated by amine-based organocatalysts. In particular, we were focused on a study of asymmetric allyl substitution of Morita-Baylis-Hillman carbonates and two-component domino reactions on sulfur-containing heterocycles. The thesis deals with the organocatalytic allyl amination of Morita-Baylis-Hillman carbonates with aromatic amines catalyzed by β-isocupreidine. The corresponding allylic amines were obtained in high yields (90-96%) with moderate enantiomeric excess. It was possible to get substances of high optical purity (ee 82-99%) by recrystallization of selected products. Furthermore, the developed method was applied in the preparation of enantiomerically enriched β-lactams, which represent valuable precursors, for example, in the synthesis of the drug Ezetimibe. The second part of the work is focused on stereoselective cyclization reactions comprising selected sulfur heterocycles. Although the cyclization reaction of...
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Enantioselective synthesis of bispirocyclic compounds
Nigríni, Martin
This diploma thesis is focused on synthesis of enantiomeric and diastereomeric pure bispirocyclic compounds via sequential Mannich/hydroamination reaction. The first part is focused on the optimization of reaction conditions of enantioselective asymmetric organocatalytic Mannich reaction of pyrazolone derivatives with isatin-derived ketimines. The enantiomerically enriched Mannich adducts were used in hydroamination cyclization. The second part of the work is focused on finding the suitable reaction conditions for performing the Mannich reaction and hydroamination as a sequential reaction leading to bispirocyclic compounds. The application of sequential reaction and selected transformations of bispirocyclic compounds was also performed. Key words Asymmetric synthesis, organocatalysis, Mannich reaction, hydroamination, sequential reaction, bispirocyclic coumpounds.
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N-heterocyclic carbene catalysis in enantioselective cycloadditions
Krejčířová, Kateřina ; Veselý, Jan (advisor) ; Baszczyňski, Ondřej (referee)
This diploma thesis deals with selected enantioselective cycloaddition reactions catalyzed by N-heterocyclic carbenes. First, we focused on studying the [4+3] cycloaddition reaction. Non-commercial ketimines were prepared as starting materials for the model reaction. Subsequently, the reaction between ketimines and salicylaldehyde was studied, where, despite all efforts, preparing the desired product was impossible. Furthermore, the [3+3] cyclization reaction was studied. Aminopyrazole and substituted α-bromenals were prepared for these purposes. However, while optimizing this reaction, the same concept was published. Finally, our attention was focused on the [3+2] cycloaddition reaction between α-bromenals and hydrazides derived from oxalic acid esters. Here, the reaction conditions were optimized, and the substrate scope was subsequently studied.
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Stereoslective addition reaction to ketimines
Franc, Michael
This diploma thesis deals with the stereoselective addition reaction of benzothiophenone derivatives to ketimines derived from isatin using bifunctional organocatalysis. The stereoselective addition reaction was optimized to provide the appropriate reaction conditions which were subsequently used to study the scope of the reaction. Keywords Organocatalysis, stereoselective synthesis, bifunctional organocatalysts, ketimines, sulphur heterocykles.
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Development of catalytic systems suitable for the enantioselective synthesis of heterocycles
Dočekal, Vojtěch ; Veselý, Jan (advisor) ; Cibulka, Radek (referee) ; Pospíšil, Jiří (referee)
The development of novel methodologies and synthetic strategies for the preparation of complex 3D heterocyclic compounds with the well-defined spatial arrangement of functional groups represents one of the most studied research problems in current synthetic chemistry. Nowadays, organocatalysis (beside transition-metal catalysis and biocatalysis) became the most popular tool, because of usage small chiral organic compound for asymmetric induction and acceleration of reaction. In this thesis, the development of novel organocatalytic methodologies for the preparation of various heterocyclic compounds is described. The utility of novel methodologies is demonstrated by easy access to chiral building block molecules or products with valuable physical or biological properties. In the first part, a novel [4+2] cycloaddition reaction of sulfur-containing heterocyclic electron-deficient alkenes with allenic compounds catalyzed by chiral tertiary amine is described. Organocatalytic cycloaddition reaction of 3-benzylidene benzo[b]thiophenones with allenoates was investigated and optimized. Dihydro-2H-pyranes were obtained in high isolated yields (up to 92%) and optical purities (up to 99% ee). The robustness and synthetic utility of the developed methodology was demonstrated by a simple work-up of...
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Development of a heterogeneous catalytic system using multiply charged cyclodextrins and proline-based organocatalysts
Zelený, Jan ; Jindřich, Jindřich (advisor) ; Baszczyňski, Ondřej (referee)
Cyclodextrins are a class of organic molecules consisting of a cyclic system of α(1→4) linked glucose units. These compounds possess a range of interesting properties and can be derivatised to suit various industrial and scientific purposes. Among their derivatives are so- called multiply charged cyclodextrins, the development and application of which is an essential part of our group's research interest. These cyclodextrin derivatives are capable of binding electrostatically to different solid sorbents, such as silicagel or alumina. This electrostatic interaction is mediated by an array of permanently positively charged moieties which are covalently attached to the primary rim of a cyclodextrin unit. The free secondary rim then offers the possibility of further derivatisation and functionalisation of this system. The resultant cyclodextrin derivative represents a modular scaffold which can be used to immobilise different functional components. This project focuses on the application of this system to the immobilisation of a Hayashi- Jørgensen-type catalyst for the purposes of heterogeneous catalysis. The work includes the assembly of the of the chosen catalytic system from its precursors and also the synthesis thereof. Furthermore, the resulting supramolecular system is tested for its catalytic...
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Preparation of organocatalysts derived from thiourea containing saccharide units
Řehůřková, Tereza ; Veselý, Jan (advisor) ; Smrček, Stanislav (referee)
4 ABSTRACT This diploma thesis is focused on the synthesis of new bifunctional thiourea organic catalysts containing a carbohydrate moiety, in particular D-glucose with modification on the primary hydroxyl group. The first part of this diploma thesis describes a modification of synthesis of the known bifunctional thiourea catalyst with 2,3,4,6-tetra-O-acetyl-β-D-glucopyranose and (1R,2R)-diaminocyclohexane. The second part is dedicated to the synthesis of new bifunctional thiourea catalysts with modification of the carbohydrate moiety. We focused on per-O-acetyl-β-D-glucopyranose derivatives with pefluoroalkyl moiety on the primary hydroxyl group. We examined different ways of the preparation of 6-O-perfluoroalkylated glucose derivatives. These perfluoroalkylated carbohydrate compounds were transformed into corresponding glycosyl isothiocyanates. Those derivatives upon treatment of (1R,2R)-diaminocyklohexane or 3,5- bis(trifluormethyl)aniline afforded new bifunctional thiourea organocatalysts.
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Organocatalytic asymmetric synthesis of various organic compounds from α,β-unsaturated aledyhes
Kamlar, Martin ; Veselý, Jan (advisor) ; Trnka, Tomáš (referee)
With regard to a fast development in the field of fluoroorganic chemisty, the intention of this diploma thesis is focused to utilize of organocatalysis by secondary amines as catalysts for preparation enantiomerically pure compounds containing fluorine atom in its structure. The preparation of these subsances is realized by way of nucleofilic addition to α,β- unsaturated aldehydes using suitable fluorine containing nuclephilic agent 1-(fluoronitromethylsulphonyl)benzene, to get appropriate 1,4-adduct.
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Synthesis of New Types of Biologically Active Substances Using the Organometallic Compounds
Korotvička, Aleš ; Kotora, Martin (advisor) ; Dvořák, Dalimil (referee) ; Starý, Ivo (referee)
This work consists of four separate chapters. Although they are seemingly different projects, they have a common feature - the application of organometallic chemistry. 1. Lusianthridin and denbinobin, the phenanthrene derivatives, can be found in plants of the family Orchidaceae. They exhibit cytostatic activity against cancer of human lung and ovarian and against promyelocytic leukemia. Therefore, new synthetic methods for these substances may be applied in research and development of new bioactive compounds. I prepared 9,10- disubstituted phenanthrenes through reactions of biphenylene with alkynes, which were catalyzed by iridium complexes. Phenanthridine derivatives are found naturally in the group benzo[c]phenanthridine alkaloids. The most famous of these include sanguinarine and chelerythrine. Sanguinarine selectively induces apoptosis (planned cell death) of human cancer cells and, therefore, is investigated as a potential antitumor agent. Chelerythrine selectively inhibits protein kinase C, leading again to apoptosis. I have studied reactions of biphenylene with nitriles catalyzed by rhodium complexes that have not been described yet. By this, I prepared a series of 6-substituted phenanthridines. 2. Carboranes are artificially prepared organic compounds of boron, which are not represented in...
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