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Preparation of organocatalysts derived from monosaccharides
Nekvinda, Jan ; Veselý, Jan (advisor) ; Trnka, Tomáš (referee)
This bachelor thesis is focused on the synthesis of organocatalysts derived from monosaccharides, in particular D-glucose and D-glucosamine, with various protecting groups. Synthesis of various thiourea catalysts and the attempt to prepare new squaramide catalysts is described. ABSTRAKT Tato bakalářská práce je zaměřena na syntézu organokatalyzátorů odvozených od monosacharidů, zejména z D-glukózy a D-glukosaminu, s různými chránícími skupinami. Dále je popsána syntéza různých thiomočovinových katalyzátorů a pokus o přípravu katalyzátoru obsahující derivát kyseliny čtvercové.
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Organocatalytic reactions leading to functionalized cyclic compounds
Formánek, Bedřich ; Veselý, Jan (advisor) ; Jindřich, Jindřich (referee)
First part is focused on finding suitable reaction conditions for organocatalytic domino Michael/Michael reaction of ethyl (E)-3-(2-thiophenyl)acrylate with α,β-unsaturated aldehydes. Second part deals with the preparation of pyrazolone derivatives from commercially available compounds and describes effects of various substituents in α-position on chemical efficiency and stereoselectivity of amination with azodicarboxylate catalyzed by quinine.
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Enantioselective synthesis of fluorinated organic compounds using iminium and enamine catalysis
Hejnová, Monika ; Veselý, Jan (advisor) ; Smrček, Stanislav (referee)
This diploma thesis deals with the scope of organocatalytic concept for the preparation of enantiomerically pure organic compounds, containing fluorine atom. Our attention was focused on the use of easily available α,β-unsaturated aldehydes and ketones as starting materials and commercially available secondary amines as catalysts. The first part of the work is dedicated to the enantioselective cyclization reaction of hydrazone (24) with cyclohex-2-enone (25). The second part describes a study of enantioselective nucleophilic addition of diethyl 2-fluoromalonate (31a) to α,β-unsaturated aldehydes (30) via enamine activation.
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Synthesis of cycles using organocatalysis and catalysis with metal complexes
Hurný, David ; Veselý, Jan (advisor) ; Trnka, Tomáš (referee)
This thesis deals with an enantioselective synthesis of cyclic compounds by using a combination of organocatalysis and transition metal catalysis. The thesis deals mainly with usage of aminocatalyst for activation of aldehydes and copper catalyst for activation of terminal triple bond. The first part is focused on the preparation of starting compounds for cyclizations (α-oxoesters, α- substituted nitroalkanes and α-substituted aldehydes). The second part concerns carbocyclization itself and optimization of reaction conditions to achieve highly stereoselective reaction. Powered by TCPDF (www.tcpdf.org)
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The use of BH carbonates in organocatalytic transformations
Tichá, Iveta ; Veselý, Jan (advisor) ; Jindřich, Jindřich (referee)
This diploma thesis is focused on the preparation of enantiomerically pure compounds based on organocatalytic allylic substitution using Baylis-Hillman carbonates. As selected substrates for the allylic substitution were chosen α-azidoketones such as azidoacetophenone, 2-azido-1-indanone and then heterocyclic compounds (N-phenylrhodanine and its derivate) belonging to the pharmaceutical privileged compounds. Other substrate for allylic substitution was allylmalononitrile. In addition, this thesis includes with synthesis of cyclic compounds based on the reaction of products of allylmalononitrile with B-H carbonates using olefin metathesis.
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Verification of flavinium salts reactivity with N- and O-nucleophiles for eventual transformation of boronic acids to corresponding amines
Honskusová, Linda ; Kotoučová, Hana (advisor) ; Holakovský, Roman (referee)
Presented diploma thesis follows the long-term study running at the Department of Organic Chemistry at the University of Chemistry and Technology Prague in the field of using flavinium salts as catalysts of oxidation reactions. The aim was to verify the reactivity of flavinium salt 13 with different types of O- and N-nucleophiles by monitoring of the corresponding C4a-adducts formation. In the thesis a simple alloxazinium salt 13 and one of the nucleophiles (hydroxylamine 25) were prepared. According to the results obtained from the UV-VIS measurements nucleophile 25 is the only one of the newly tested wchich formed desired C4a-adduct 13d with alloxazinium salt 13. KEYWORDS flavinium salt, nucleophile, C4a-adduct, organocatalysis, IBSE
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The preparation of chiral NHC carbene precatalysts
Krejčířová, Kateřina ; Veselý, Jan (advisor) ; Míšek, Jiří (referee)
This bachelor thesis is focused on the preparation of chiral NHC carbene precatalysts, which are used as organocatalysts in a variety of organic transformations leading to the formation of optically active compounds. In the course of this work, several triazolium salts were prepared from suitable starting materials using six reaction steps. Triazolium salts derived from oxazolidinone were obtained from well available starting materials, arylhydrazines and phenylalanine.
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