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1
Essenfeld, Amy Pia. "Asymmetric intramolecular Diels-Alder reactions." Thesis, Massachusetts Institute of Technology, 1985. http://hdl.handle.net/1721.1/15197.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemistry, 1986.MICROFICHE COPY AVAILABLE IN ARCHIVES AND SCIENCE
Includes bibliographical references.
by Amy Pia Essenfeld.
Ph.D.
2
Göstl, Robert. "Photocontrolling the Diels-Alder reaction." Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät, 2014. http://dx.doi.org/10.18452/17060.
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Die Aufgabe des synthetischen Chemikers besteht darin neue Moleküle, Bauelemente oder Medikamente aus einfachen Edukten herzustellen. Die wachsende Komplexität dieser synthetischen Produkte bedingt jedoch, dass die Entwicklung der dazu benötigten Werkzeuge ebenso schritthalten muss. Licht ist mit seiner herausragenden räumlichen, zeitlichen und energetischen Auflösung sowie seinem nicht-invasiven Charakter den traditionell verwendeten Stimuli überlegen. In dieser Arbeit wurde durch die Kombination eines molekularen Photoschalters mit der Diels-Alder-Reaktion die Photokontrolle über eine dynamisch-kovalente Reaktion erlangt. Das Ergebnis der Reaktion eines furyl-substituierten Diarylethens mit Maleinimid konnte ausschließlich durch die Bestrahlung mit Licht unterschiedlicher Farbe bestimmt werden. Dieses prototypische System wurde dann unter Erhalt seiner photochemischen Eigenschaften für die Anwendung unter physiologischen Bedingungen weiterentwickelt. Es konnte die photoreversible Freisetzung therapeutisch wirksamer Konzentrationen verschiedener Anti-Tumor-Medikamente in gepufferter, wässriger Lösung bei Körpertemperatur durch bioorthogonales sichtbares Licht ausgelöst werden. Weiterhin wurden die Feinabstimmung der Freisetzung dieser photoschaltbaren Diels-Alder-Addukte und eine ausführliche Untersuchung der Freisetzungs-Dynamiken gezeigt. Hierdurch wurde das System auf eine Stufe gehoben, an der in vivo Anwendungen erwägt werden können. Des Weiteren wurden die Grundlagen zur Implementierung der photokontrollierbaren Diels-Alder-Reaktion in der reversiblen kovalenten Funktionalisierung von Kohlenstoffnanoröhren gelegt. Trotzdem noch keine erfolgreiche Funktionalisierung nachgewiesen werden konnte, wurde durch die Untersuchung der zugrundeliegenden Prinzipien der Weg für die Anwendung fortgeschrittener Techniken zur Modulation physikochemischer Eigenschaften von sp2-Kohlenstoff Allotropen geebnet.The synthetic chemist’s profession is devoted to the formation of chemical bonds to create new molecules, building blocks, or drugs from basic starting materials. However, the growing complexity of these synthetic products necessitates that the development of the tools to fulfill this task must also keep pace. Light as a stimulus with its superior spatial, temporal, as well as energetic resolution in combination with its non-invasive character outperforms the traditional means to control a chemical reaction, such as heat, pressure, or pH, clearly. In this work, the unprecedented reversible photocontrol over a dynamic covalent reaction was established by the combination of a molecular photoswitch and the well-known Diels-Alder reaction. The outcome of the reaction of a furyl-substituted diarylethene and maleimide could be determined exclusively by illumination with differently colored light. This prototypical system was then advanced for the application under physiological conditions while retaining its superior photochemical properties. The release of therapeutically effective concentrations of different antitumor agents could be photoreversibly triggered in buffered, aqueous solution at body temperature employing bioorthogonal visible light. It is shown how the release properties of these photoswitchable prodrugs can be fine-tuned and a thorough investigation of the release dynamics is presented promoting this system to a level where in vivo application can be considered. Furthermore, the foundations for the implementation of the photocontrollable Diels-Alder reaction in the reversible covalent functionalization of carbon nanotubes have been laid. Despite the fact that a successful functionalization has not yet been achieved, the basic principles were investigated and have paved the way for the application of more advanced techniques to effectively modulate the physicochemical properties of sp2-carbon allotropes.
3
Ho, David Gai. "Adventures in Lewis acid catalyzed highly hindered Diels-Alder reactions; Novel non-Diels-Alder Diels-Alder reaction and its utility for the synthesis of haterumaimide E." Diss., Restricted to subscribing institutions, 2007. http://proquest.umi.com/pqdweb?did=1495960681&sid=1&Fmt=2&clientId=1564&RQT=309&VName=PQD.
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4
Cernak, Timothy Andrew. "A Diels-Alder approach to palau'amine /." Thesis, McGill University, 2007. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=103369.
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Described in this thesis is the development of a key Diels-Alder reaction for use in a total synthesis of the potently immunosuppressant marine alkaloid palau'amine. This study focuses on the originally proposed structure of palau'amine. The strategy utilizes a computationally designed thiohydantoin dienophile as the 2pi component and a thermally stable 2-silyloxy-5-(silyloxymethyl)cyclopentadiene as the 4pi component in the critical Diels-Alder reaction. Essential to the design and study of these partners was the use of computational density functional theory (DFT) predictions.Four families of dienophiles---oxazolones, dehydroalanines, hydantoins and thiohydantoins---were investigated. The hydantoins and thiohydantoins react with cyclopentadiene with up to 13:1 exo-selectivity while the dehydroalanines are modestly selective and the oxazolones are unselective. The exo-selectivity of the hydantoin and thiohydantoin dienophiles is attributed to a novel stabilizing interaction whereby the lone pair of electrons on nitrogen interacts with a developing positive charge on the diene in the transition state. In terms of reactivity, the oxazolones are the superior dienophiles. The reactivity of the thiohydantoins is greater than that of analogous hydantoins and approaches that of the oxazolones. The bolstered reactivity of the thiohydantoins is attributed to the increased donation of the nitrogen lone-pair into the thiocarbonyl bond. This phenomenon was recognized first in DFT predictions and then proven experimentally. Synthetic access to the requisite beta-(chloromethylene)thiohydantoins necessitated the development of a reaction between dilithium diamides and thiophosgene.
2-silyloxy-5-(silyloxymethyl)cyclopentadienes were studied experimentally and computationally and found to be much more stable than conventional 5-substituted cyclopentadienes towards thermal decomposition by 1,5 hydride shift. The new dienes undergo Diels-Alder reaction with oxazolone and thiohydantoin dienophiles with exoselectivities as high as 6:1 for nonchlorinated dienophiles. Fully functionalized chlorinated exo-cycloadducts were prepared with up to 1.5:1 selectivity and subjected to oxidative ring-opening to reveal the persubstituted core of palau'amine.
5
Butt, Nicholas A. "A Diels-Alder approach towards pyrroindomycins." Thesis, University of Nottingham, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.555692.
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Many natural products contain a tetramic acid (pyrrolidine-2,4-dione) ring system as an integral part of their structure. They exhibit a wide range of biological activities and are structurally diverse, making them an attractive target for the synthetic chemist. The pyrroindomycin antibiotics are an example of such natural products which contain a spirotetramate core. Studies towards the total synthesis of the pyrroindomycins are described within this thesis, which involve inter- and intra- molecular Diels-Alder approaches towards the synthesis of the spirotetramate core of the natural products. In addition to these synthetic strategies, the relative stereochemistry of the aglycone (previously unknown) was elucidated using NMR spectroscopy, and the findings reported herein. Diels-Alder studies were performed on a model tetramic acid dienophile and the reactivity of this type of system compared to dehydroalanine derivatives. Several spirotetramates were prepared utilising this method, in order to determine if a similar synthetic approach could be used to synthesise the spirotetramate core of the pyrroindomycins. In addition, a spirotetramate was prepared using a nitroalkene dienophile precursor. A number of intramolecular Diels-Alder reactions involving dehydroalanine and nitroalkene dienophiles were also attempted, in order to synthesise a spirotetramate precursor which could be elaborated to the natural products.
6
Moloney, B. A. "Stereochemically controlled intramolecular Diels-Alder reactions." Thesis, Cardiff University, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.378452.
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7
Robson, David C. "Diels-Alder cycloaddition for novel bioanalysis." Thesis, University of Strathclyde, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.428842.
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8
Birkinshaw, Timothy Nicholas. "Diels-Alder routes to Prosopis alkaloids." Thesis, University of Cambridge, 1987. https://www.repository.cam.ac.uk/handle/1810/270418.
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This thesis describes the investigation of the Diels-Alder reaction of the imine (140) with the diene (141) to give four products (142,143,156, 157). At low temperatures the enone (156) is the major product while at ambient temperature the bicyclic compounds (142) and (143) predominate. The reaction is highly solvent dependent, with the best results being obtained in benzene solution. Lewis acids appear to have little effect on the course of the reaction. The reaction of the imine (140) with the TBDMSO diene (159) gives the silyl enol ethers (160) and (161) as well as the above four products. Possible mechanisms are discussed. COOM. OSIM., In order to investigate asymmetric induction the 8- phenylmenthyl derived imine (194) was reacted with the diene (141) under a variety of conditions but no asymmetric induction was seen in the exo adducts, and only a small degree in the endo adducts. The bromination and Baeyer-Villiger oxidation of the ketone (142) were investigated and the resultant lactone (209) was converted into the bromide (258). ISOPROSOPININE A (84) ISOPROSOPININE B (S3) Several methods to prepare a suitable side chain for isoprosopinine A were investigated. The prosopis alkaloids isoprosopinine A (84) and B (85) were prepared by alkylation of the sulphones (252) and (266) with the bromide (258) followed by reductive removal of the N-tosyl and sulphone moieties with sodium amalgam. The imine (274) has been prepared and shown to undergo a Lewis acid catalysed imino-Diels-Alder reaction with the diene (141) to give the adducts (283) and (284). hCH,M=CHCOjM» (2T4) Alternative imines for asymmetric synthesis, such as (299) and (288) have been investigated. Preparation of the sulphinamide imine (299) has proved difficult. Attempts to carry out aqueous Diels-Alder reactions of the silyloxydiene (159) with iminium ions, generated in situ from amines, aldehydes and acids, have proved fruitless.
9
Yamamoto, Yuhei. "Catalytic asymmetric nitroso Diels-Alder reaction." 京都大学 (Kyoto University), 2006. http://hdl.handle.net/2433/143962.
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10
Strange, Gregory Alan. "RESPONSIVE MATERIALS VIA DIELS-ALDER CHEMISTRY." DigitalCommons@CalPoly, 2012. https://digitalcommons.calpoly.edu/theses/710.
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The corrosion of infrastructure imposes a significant monetary cost, and at times human cost, upon society. Methods to improve corrosion resistance of materials are described herein which utilize the reversibility of the Diels-Alder reaction to impart thermal responsiveness upon materials. Such stimuli responsiveness can potentially play a role in self healing properties which lead to reduced cracking and thus increased corrosion protection.
Reversible Diels-Alder chemistry was utilized to manipulate the surface energy of glass substrates. Hydrophobic dieneophiles were prepared and attached to glass slides and capillaries to yield a nonwetting surface. Thermal treatment of the surfaces cleaved the Diels-Alder linkage, and resulted in the fabrication of a hydrophilic surface. Preliminary analysis utilized contact angle (CA) measurements to monitor the change in surface energy, and observed a hydrophilic state (CA - 70±3°) before attachment of the dieneophile to a hydrophobic state (CA - 101±9°) followed by regeneration of the hydrophilic state (CA - 70±6°) upon cleavage of the Diels-Alder linkage. The treatments were then applied to glass capillaries, with effective treatment confirmed by fluid column measurements. Patterned treatments were also demonstrated to provide effective fluid flow gating.
Reversible Diels-Alder linkages were incorporated into polymer thermoset binding resins in order to provide a means by which a crosslinked thermoset could undergo stimuli responsive reversible crosslinking. The binder systems which were utilized included two types of amine curing agents, polydimethylsiloxane (PDMS) and Jeffamine® polyetheramines (PEA), and two types of epoxy resins, EPON resin based on diglycidyl ether of Bisphenol-A and epoxidized soybean oil. Various dienes and dienophiles were employed to functionalize the selected binder systems and were met with various degrees of success. The synthetic technique which proved to be the most promising was the Diels-Alder modification of the epoxidized soybean oil.
11
Lin, Denny. "Intramolecular Diels-Alder reactions of alkenylboranes & a hetero Diels-Alder approach to the total synthesis of Martinelline." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp04/mq29224.pdf.
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12
Gomes, Maria Goretti. "Diels-alder reactions of a cyclopentadienone derivative." Diss., Columbia, Mo. : University of Missouri-Columbia, 2007. http://hdl.handle.net/10355/4670.
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Thesis (Ph. D.)--University of Missouri-Columbia, 2007.The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on February 13, 2008) Vita. Includes bibliographical references.
13
Knol, Jochem. "Chiral Lewis acid catalyzed Diels-Alder reactions." [S.l. : [Groningen : s.n.] ; University of Groningen] [Host], 2008. http://irs.ub.rug.nl/ppn/.
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14
Dyer, Jolon Matthew. "Diels-Alder approaches to anti-cancer prodrugs." Thesis, University of Canterbury. Chemistry, 1998. http://hdl.handle.net/10092/6781.
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This thesis concerns the design and synthesis of compounds relevant to a new strategy for the synthesis of anti-cancer prodrugs. The focus of this strategy is Diels-Alder chemistry leading to oxygen or sulfur-bridged polycyclic adducts. Bridge cleavage of such adducts can result in the formation of polycyclic, aromatic compounds, a structure characteristic of anti-cancer drugs which act via intercalation.
Part A describes the design of a model system for the synthesis of Diels-Alder adducts as prodrugs. A range of isobenzofurans, along with a range of fumaramide and N-aryl maleimide derivatives, were synthesised, and these were reacted together in Diels-Alder fashion. The resulting adducts were bridge cleaved.
Part B describes the introduction of functional groups into Diels-Alder adducts. The functional groups investigated included alkylating and hydrogen-bonding substituents, introduced via N-aryl maleimide based dienophiles. A range of isobenzothiophenes was also synthesised, and these were used to generate sulphur-bridged Diels-Alder adducts, with the resulting increase in stability proving advantageous in some instances. A variety of functionalised adducts and their bridge cleaved derivatives were prepared. The biological properties of some showed promise as leads for the development of anti-cancer compounds.
15
Smith, Stephen Geoffrey. "The Diels-Alder chemistry of substituted pyrroles." Thesis, University of Birmingham, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.403449.
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Taylor, Sara Louise. "Enantioselective Diels-Alder reactions of 2H-pyrans." Thesis, University of Liverpool, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.480888.
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17
LAUGRAUD, SYLVAIN. "Syntheses d'anthracyclinones par cycloadditions de diels-alder." Paris 6, 1989. http://www.theses.fr/1989PA066614.
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Les anthracyclines constituent une vaste famille de produits naturels aux proprietes antitumorales exceptionnelles. Apres avoir presente, dans le preambule, les grands axes de recherche qui ont debouche sur l'utilisation clinique de ces drogues, nous exposons nos syntheses d'anthracyclinones, aglycones d'anthracyclines, selon une strategie basee sur la reaction de diels-alder. La deoxy-11 daunomycinone constitue la cible de la premiere partie de nos travaux. Apres avoir passe en revue les grandes strategies de synthese de cette anthracyclinone, nous exposons nos syntheses formelles de la deoxy-11 daunomycinone et de son analogue demethoxy-4. Dans la seconde partie, nous presentons une approche de la deoxy-4 (epsilon)-rhodomycinone basee sur la cycloaddition de deux entites hautement fonctionnalisees. L'adduit tetracyclique ainsi obtenu comporte potentiellement toutes les fonctionnalites de l'anthracyclinone cible. L'aromatisation de cet intermediaire donne alors acces a un analogue structural d'une anthracyclinone naturelle non usuelle. Nous exposons, dans une partie annexe, divers aspects physicochimiques de la chimie sous haute pression. Ces elements permettent d'apprehender les atouts de cette technique d'activation qui a permis la realisation de nos differentes syntheses
18
Evans, Jessica. "Synthesis of Highly Fluorinated Diels-Alder Polyphenylenes." Diss., Virginia Tech, 2010. http://hdl.handle.net/10919/39179.
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Fluoropolymers have useful properties including high thermal stability, chemical resistance, low dielectric constants, and both hydrophobic and oleophobic character, as compared to non-fluorinated analogues. Meanwhile, Diels-Alder polyphenylenes (DAPPs) are known for thermal stability as well as their rigid structure and glassy physical characteristics, which have led to a variety of film and membrane applications. This dissertation merges these two fields by demonstrating a novel and general synthetic approach to highly fluorinated DAPPs. These polymers are expected to retain the physical characteristics of glassy, non-fluorinated DAPPs while also incorporating the desirable attributes of fluoropolymers.
The polymer synthesis described herein is based on the well-established polycondensation of bis(cyclopentadienone) (CPD) monomers and dialkynes. Our first main scientific contribution is a general method for preparing CPDs containing both a fluoroaromatic linker and variable fluoroaromatic head-groups. Our CPD synthesis uses nucleophilic aromatic substitution reactions of cyclopentadienyl anions and perfluoroarenes, as well as a new catalytic method of converting cyclopentadiene methylene (CH₂) groups into the corresponding ketones (C=O) that is the primary dissertation subject of Brian S. Hickory in our laboratory. The overall synthesis is notable for its use of inexpensive starting materials, its efficiency, and its structural versatility.
Our second main contribution is the synthesis of novel highly fluorinated Diels-Alder polyphenylenes (DAPPs). Fluorinated DAPPs varied in their molecular weight, in the identity of the lateral fluoroaryl substituent (pentafluoro-phenyl or tetrafluoro-4-pyridyl), and in the structure of the aromatic dialkyne monomer. These polymers are glassy materials with high glass transition temperatures and high thermal stability. Since the polyphenylene structure is intrinsically rigid, the polymers form brittle films even at molecular weights of over 30,000 (Mw). Unlike many fluoropolymers, the fluorinated DAPPs are freely soluble in common organic solvents such as tetrahydrofuran and chloroform. An unknown side reaction competes with the polymer propagation and reduces the highest obtainable molecular weights, which limit the ability to form films. However, a stoichiometric imbalance leads to highly fluorinated polyphenylene oligomers terminated with either alkyne or CPD end groups (Mn = 9000).
Because preliminary experiments had shown that the desired Diels-Alder propagation reaction was slower than expected, we also undertook a detailed model study of the reaction conditions needed for Diels-Alder reactions of fluorinated CPDs and aromatic alkynes. These experiments showed that protic polar solvents (e.g., m-cresol) and conventional heating at ca. 150 °C optimize reaction rate while minimizing side-reactions that can contribute to lower molecular weight in corresponding polymerization reactions.Ph. D.
19
Tan, Siu Min. "Multicomponent Diels-Alder Sequences of 1-Aminodendralenes." Phd thesis, Canberra, ACT : The Australian National University, 2017. http://hdl.handle.net/1885/143040.
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This thesis explores the use of in situ generated acyclic
1-aminodendralenes in multicomponent diene-transmissive
Diels-Alder (DTDA) reaction sequences. Dendralenes have
previously been shown to generate polycyclic frameworks in a
step-economic manner. The 1-amino substituent is shown to promote
very high levels of site selectivity in these processes.
Chapter 1 reviews the Diels-Alder reactions of
1-amino-1,3-butadienes and is divided
into three sections. The first two sections cover the Diels-Alder
reactions of
1-amino-1,3-butadienes and 1-amino-3-siloxy-1,3-butadienes
(Rawal’s dienes)
generated with a stoichiometric amount of amine. The third
section covers
enantioselective Diels-Alder reactions involving
1-amino-1,3-butadienes generated in
situ with a catalytic amount of a chiral amine. While there have
been many reports of
Diels-Alder reactions of 1-amino-1,3-butadienes and
1-amino-3-siloxy-1,3-butadienes,
there has been only one involving a semi-cyclic
1-amino[3]dendralene. There have been
few examples which combine these Diels-Alder reactions with other
transformations in
multicomponent reactions to generate polycyclic frameworks.
Chapter 2 describes the use of acyclic 1-amino[3]dendralenes in
multicomponent
reactions to generate a diverse range of heterocyclic structures.
The condensation/Diels-
Alder reaction sequence was tolerant of a variety of amines as
well as carbon and
hereoatom-based dienophiles. The Diels-Alder reactions of
1-amino[3]dendralenes were
highly site-selective, taking place exclusively at the amine
substituted 1,3-butadiene
unit. The sequence was extended to a one-pot four-component
reaction by including an
additional dienophile for a Diels-Alder reaction to take place at
the newly generated
semi-cyclic diene. These condensation/Diels-Alder/Diels-Alder
cycloadducts were
generated with high diastereoselectivity, the origins of which
were investigated and
explained with the use of density functional theory calculations
(carried out by Prof
Paddon-Row). By reversing the order of events, that is performing
a Diels-Alder
reaction on the skipped dienal precursor before the
condensation/Diels-Alder reaction
sequence, constitutional isomers were accessed. The second
Diels-Alder reaction could be performed intramolecularly when an
amine bearing an alkenyl substituent was used. This
condensation/Diels-Alder/intramolecular Diels-Alder reaction
sequence furnished a variety of tricyclic and tetracyclic
heterocycles.
Chapter 3 describes the use of acyclic 1-aminodendralenes bearing
chiral amines in
organocatalytic, enantioselective Diels-Alder reactions to
deliver enantioenriched
cycloadducts. The enantioselective Diels-Alder reaction between
1-amino[3]dendralenes, the condensation product of skipped
dienals and chiral amines,
and various dienophiles followed by elimination of the amine
generated trienal
cycloadducts in good yield and high enantioselectivity. The
reaction tolerates
substitution on the skipped dienal as well as dienophiles
possessing an aldehyde
substituent at the α position. Extension of this methodology by
performing Wittig and Diels-Alder reactions on the trienal
cycloadducts enabled access to enantioenriched polycyclic
products. By using a diene-dialdehyde as the starting precursor,
it is anticipated that the Horeau principle would operate in the
twofold condensation/Diels-Alder/elimination reaction sequence
would furnish the cycloadduct in high enantioselectivity. A
preliminary attempt successfully generated the desired
cycloadduct as the major product.
20
Buckle, Ronald Neil. "Asymmetric Diels-Alder studies involving chiral acetylenic diesters and investigations of an intramolecular Diels-Alder approach to the pentalenolactones." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp03/NQ36199.pdf.
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Abaee, Mohammad Saeed. "Lewis acid catalyzed and self-assembled Diels-Alder reactions (LACASA-DA), a new strategy to control Diels-Alder reactions." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape7/PQDD_0026/NQ37867.pdf.
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Borm, Claudia. "Enantioselektive Cycloadditionssequenzen." [S.l. : s.n.], 1997. http://deposit.ddb.de/cgi-bin/dokserv?idn=954338189.
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Olsson, Philip. "Datorbaserad analys av enzymdesign för Diels-Alder reaktioner." Thesis, KTH, Skolan för kemivetenskap (CHE), 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-34153.
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This thesis has been focused around the Diels Alder reaction with the goal to design an enzyme catalyzed reaction pathway. To achieve this goal computer aided enzyme design was utilized. Common traditional methods of computational chemistry (B3LYP, MP2) do not do well when calculating reaction barriers or even reaction energies for the Diels Alder reaction. New calcu- lation methods were developed and tested. This was the focus of the first part of the thesis, by choosing a small system, extensive and heavy calculations could be done with CBS-QB3. Then by benchmarking faster methods of calculation (SCS-MP2, M06-2X) against the results, they could be graded by efficiency and cost. This was done anticipating that the same accuracy could be applied to larger systems where CBS-QB3 cannot be used. In the second part activating groups were investigated for both the diene and the dienophile, along with their effects on reaction rates. A qualitative analysis was done. This is important not only for the uncatalyzed reaction, but also interesting when searching for possible substrates for the enzyme reaction. In the last part the thesis presents a designed enzyme that catalyzes Diels Alder in silico using ∆5−3−Keto steroid isomerase. Using empirical calculations, the enzyme was scanned for catalytic activity. The catalytic effect was then showed with ab initio Quantum chemical calculations.
24
Jackson, P. Mark. "Diels-Alder reactions of heterocyclic fused α-pyrones." Thesis, Loughborough University, 1991. https://dspace.lboro.ac.uk/2134/27733.
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The chemistry of heterocyclic analogues of orthoquinodimethane is reviewed. Benzothieno[2,3-c]pyran-3-ones and the isomeric [3,2-c]pyranones are stable analogues of benzothiophene-2,3-qyinodimethane. When heated with alkynes they undergo Diels-Alder reaction to give, after loss of carbon dioxide, dibenzothiophenes.
25
De, Bue Geneviève. "Réactions de Diels-Alder sur les 3-vinylindolizines." Doctoral thesis, Universite Libre de Bruxelles, 1995. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/212575.
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Thadani, Avinash N. "Alkenyl- and dienylboronate tethered intramolecular diels-alder reactions." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape10/PQDD_0001/MQ40737.pdf.
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Hedger, Paul Christopher Marcus. "Studies on the promotion of Diels-Alder reactions." Thesis, University of Oxford, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.386638.
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Shah, Saral. "SOLUTION PROCESSIBLE AROMATIC POLYIMIDES VIA DIELS ALDER PRECURSOR." Master's thesis, University of Central Florida, 2008. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/3509.
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Aromatic polyimides are interesting materials since they possess outstanding key properties such as thermoxidative stability, high mechanical strength, high modulus, excellent electrical properties, and superior chemical resistance. However, their low solubility makes them difficult to characterize, process and obtain high molecular weight polymer. In this report, we synthesized a series of precursor polymers that contains Diels-Alder (DA) adducts of anthracene. Different dienophiles were tried. These precursor polymers are soluble in common organic solvents such as chloroform and can be easily processed to thin films. Heating the film above 215 degree induce retro-DA reaction, which generated the fully aromatic polyimides in situ. The solid-state retro-DA reactions were monitored by ATR-FTIR and UV-Vis spectra. The fully aromatic polyimides are highly stable and their thin films are insoluble in organic solvents. Profilometry and AFM studies showed that after the thermal treatment, the films are smooth and pin-hole free, while the volumes decreased with a percentage close to the weight loss caused by retro-DA reaction. These Polymers can have a wide range of potential applications from thermal patterning polymers to organic photovoltaics.M.S.
Department of Chemistry
Sciences
Industrial Chemistry MS
29
Hirst, David J. "A Diels-Alder approach to naturally occurring octahydronaphthalenes." Thesis, University of Nottingham, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.423647.
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Wood, Jane E. "The retro Diels-Alder route to diatomic sulfur." Thesis, University of Liverpool, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.317277.
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Wilson, Robert Darrin. "The synthetic applications of Aza-Diels-Alder reactions." Thesis, University of York, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.304291.
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Willis, Nicky John. "A hetero-Diels-Alder strategy towards the rubromycins." Thesis, Queen Mary, University of London, 2014. http://qmro.qmul.ac.uk/xmlui/handle/123456789/9072.
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Due to their interesting biological properties and complex molecular architectures, the rubromycin family of natural products, have attracted the attention of a number research groups over the last sixty years. Despite this significant interest, there is still a requirement for a short, robust, and modular synthetic route towards these intriguing secondary metabolites. This thesis presents an investigation into the application and development of Bray’s recent [4+2] cycloaddition methodology, towards achieving this goal (Scheme I). Scheme I. Retrosynthetic analysis of the rubromycin scaffold The initial introductory chapter outlines the structural relationships and biological properties of the rubromycins, in addition to providing details of the current understanding of their biochemical synthesis. This is followed by a comprehensive review of the five synthetic strategies used to construct the challenging [5,6]-bisbenzannulated spiroketal rubromycin core outlined in turn. In the third and final introductory chapter, the application and relative merits of these strategies towards the synthesis of fully elaborated rubromycin scaffolds is discussed. The results of this investigation towards a flexible and modular synthesis of γ-rubromycin are then presented and discussed in chapter four. The three main topics covered are; exploration of synthetic routes towards the napthazarin (II), exploration of synthetic routes towards the ortho-quinone methide (III), and utility of the orthoquinone methide in ‘inverse’ electron-demand [4+2] cycloaddition reactions. The experimental details of this investigation and selected 1H and 13C are also reported in chapters 5 and 6 respectively.
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Shah, P. "Diels-Alder reactivity of indol-2 3-quinodimethanes." Thesis, Imperial College London, 1988. http://hdl.handle.net/10044/1/47250.
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Grossmith-Hague, Catharine. "New catalysts for the hetero Diels-Alder reaction." Thesis, University of Bath, 2002. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.760796.
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Marsh, Andrew. "Intramolecular Diels-Alder reactions of sulphonyl-substituted trienes." Thesis, Imperial College London, 1991. http://hdl.handle.net/10044/1/63786.
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This thesis is divided into two parts. The first part describes the development ofmethodology for the intramolecular Diels-Alder (IMDA) reaction of sulphonyl-substituted trienes. A brief introduction to the area of the IMDA reaction is provided. This provides the basis for the rational development of a new class of IMDA substrate. A series of E- and Z-sulphonyl substituted deca- and undecatrienes was synthesised and their cyclisation behaviour under thermal conditions examined. Cyclisation of (IE, 7E, 9E)-l-phenylsulphonyl-l,7,9-undecatriene gave a 6:1 mixture of cis- and trans-fused bicyclic sulphones. Contrastingly, cyclisation of the corresponding (Z, £ , E)- sulphonyltriene yielded a 3:1 mixture of trans- and cis-fused isomers. These results added weight to the postulate that a suitable dienophile could exert a sereocontrolling influence over the outcome of the IMDA reaction. The lower homologues of these trienes were found to provide similar results. The reaction of a series of a methylated trienes was carried out to examine the degree of stereocontrol exerted by the phenylsulphone group over the [4+2] cycloaddition. Characterisation of the bicyclic sulphones derived from these reactions is supported by X-ray crystallographic evidence and supplemented by chemical correlation. The second part begins with a review of approaches towards the total synthesis of the CD ring of vitamin D3 and its analogues. This introduces the use of the IMDA reaction as a concise strategy towards the construction of a vitamin D3 CD ring synthon in a stereocontrolled fashion. The synthesis of a suitable model substrate and its cyclisation via a novel IMDA route is described. With the success of this reaction, an enantiomerically pure triene was synthesised. Cyclisation under thermal conditions led to material suitable for elaboration to the natural product, vitamin D3. The diastereomeric bicyclic tetrahydroindene adducts were epoxidised to allow their separation and characterisation using spectroscopic techniques.
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Warmus, Joseph Scott Warmus. "Synthetic studies of the intramolecular Diels-Alder reaction." Thesis, Massachusetts Institute of Technology, 1990. http://hdl.handle.net/1721.1/13718.
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Balfe, Andrew M. "In-situ hetero Diels-Alder procedure for hippeastrine." Thesis, University of East Anglia, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.423397.
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Salafia, Vittoria. "Synthesis and transformation of difluorinated Diels-Alder cycloadducts." Thesis, University of Leicester, 2004. http://hdl.handle.net/2381/30089.
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This thesis describes the synthesis of highly substituted geminally difluorinated cyclohexenols based on Diels-Alder reactions between a difluorinated dienophile and furans (furan, 2-methyl and 2,3-dimenthyl) in presence of stannic chloride. The dienophile was synthesised in two different ways: a literature procedure, starting from the commercially available trifluoroethanol and new route involving an organometallic reagent.;Sulphur electrophile chemistry applied to the endo and exo cycloadducts gained stereo- and regio- control completely. Full protection of the free hydroxyl group was required before two different ring-opening strategies could be implemented: a carbanionic and a reductive method were attempted to ring-open the 7-oxabicyclo[2.2.1]heptenyl system. The scope of these methodologies was investigated with furan, 2-methyl and 2,3-dimethyl furan cycloadducts. When a stoichiometric amount of the Lewis acid (stannic chloride) was used in the cycloaddition with furan, an interesting bicyclic carbonate was afforded. To understand the mechanism of the reaction and the role of the Lewis acid in binding the cycloadduct, crystals were grown and an interesting complex was obtained.;Useful vinyl bromide products (endo and carbonate) were generated by cycloaddition between the difluorinated alkenoate and 3-bromofuran in the presence of 1.0 equivalents of tin tetrachloride. Suzuki coupling reaction of endoadduct with phenylboronic acid was carried out under Leadbeater's aqueous microwave conditions. Finally, dihydroxylation of the ring opened products and deprotections of the protected hydroxyl groups delivered the required gem- difluorinated polyhydroxy cyclohexane allowing for the first time the synthesis of cyclitol analogues via Diels-Alder reaction.
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Ward, Simon Edward. "Novel amino-acids from imino Diels-Alder reactions." Thesis, University of Cambridge, 1997. https://www.repository.cam.ac.uk/handle/1810/283723.
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Gordon, Richard Spencer. "Intramolecular Diels-Alder reactions of conformationally restricted systems." Doctoral thesis, University of Cape Town, 2000. http://hdl.handle.net/11427/6309.
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Bibliography: leaves 184-191.In the first phase of this investigation, the synthesis of triene systems, linked via a diester tether was investigated with the aim of studying the respective thermal Intramolecular Diels-Alder (IMDA) properties. It was envisaged that the diene and dienophile would be linked via a conformationally restricted spacer, trans-cyc1ohexane-l,2-dicarboxylic acid anhydride.
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Kidane, Aklilu Asefaw. "Retro-Diels-Alder routes to 4,5 disubstituted cyclopentenones." Master's thesis, University of Cape Town, 2005. http://hdl.handle.net/11427/8660.
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Includes bibliographical references ( leaves 78-81)Investigation into the synthesis of 4,5-disubstituted cyclopentenones was conducted in light of recent interest on cyclopentenone prostaglandins (PGs) as a new class of anti-viral and anti-inflammatory agents. The strategy involved conjugate addition of various organocuprates to tricyclodecadienone derived from dicyclopentadiene and gave 5-exo-substituted tricyclodecadienones. Attempts to alkylate the kinetic lithium, copper and quaternary ammonium enolates generated from 5-exo-substituted tricyclodecadienones with alkylhalides were unsuccessful. Even in the presence of strong cation solvating hexamethylphosphoramide (HMPA) (±30% co-solvent), lithium enolates proved inert. However, trapping the magnesium enolate generated from the 1, 4-addition of n-butylmagnesium bromide to tricyclodecadienone with aldehydes yielded β-ketols of syn and anti-relative configuration. Due to their labile nature, the β-ketols were dehydrated to their corresponding stable enones. Achiral retro-Diets-Alder reactions were first attempted on 5-exo-substituted tricyclodecadienones using several Lewis-acid catalysts. 4-Substituted-2 cyclopentenones were isolated in good yield and no double bond rearrangement or decomposition was observed. Similar results were also obtained with the dienones generated from dehydration of β-ketols to give αα',ββ'-unsaturated cyclopentadienones in good yield. The synthesis of enantiomerically pure 4- Substituted cyclopentenones and 4- butyl-5-butylidene-cyclopent-2-enone via chiral Lewis-acid catalysed asymmetric retro-Diets-Alder reactions were unsuccessful. Chiral Lewis-acids were prepared in situ from selected Lewis-acids and chiral ligands containing the diol functionality namely BINOL and the TADDOLs.
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Reutenauer, Philippe. "Réactions de Diels-Alder et chimie dynamique constitutionnelle." Université Louis Pasteur (Strasbourg) (1971-2008), 2006. https://publication-theses.unistra.fr/public/theses_doctorat/2006/REUTENAUER_Philippe_2006.pdf.
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La chimie dynamique constitutionelle (CDC) tire profit de la réversibilité des interactions entre les molécules pour conférer un caractère adaptatif aux systèmes qu’elle met en oeuvre. Les bibliothèques combinatoires dynamiques sont composées à partir de briques de base qui forment de manière réversible un grand nombre de combinaisons à l’équilibre thermodynamique. L’application d’une contrainte comme l’introduction d’une cible présentant une information structurelle et induisant une reconnaissance moléculaire préférentielle par certains éléments de la bibliothèque peut déplacer l’équilibre thermodynamique. Ce phénomène peut être interprété comme une sélection, menant éventuellement à une amplification, ou comme une évolution du système sous la pression d’une contrainte. Pour obtenir ces propriétés, il est important de disposer de réactions chimiques réversibles qui laissent les interactions supramoléculaires guider son évolution. Le petit nombre de réactions covalentes réversibles disponibles et utilisables dans des conditions douces propices à la reconnaissance moléculaire est un facteur limitant pour le développement de la CDC. Le travail qui a été effectué pour cette thèse de doctorat vise à développer des systèmes basés sur la chimie de la réaction de Diels-Alder fournissant au niveau moléculaire la fonction de jonctions dynamiques entre des briques de base. Des molécules formant à température ambiante des adduits dynamiques ont été identifiées par un criblage, avec comme point de départ les données de la littérature, puis le jeu sur la substitution des produits de départ pour augmenter leur réactivité, et réduire la stabilité de leurs adduits de Diels- Alder. Cette approche a abouti à l’identification de réactions équilibrées entre les fulvènes et certaines cyanooléfines : les dicyanofumarates et les tricyanoéthylènecarboxylates. Leurs fortes réactivités résultent de leur importante électrodéficience et s’expriment par des cinétiques d’équilibration inférieures à la minute à température ambiante. Ces équilibres, et leurs variations avec la température, ont été caractérisés pour des systèmes simples, afin de servir de preuve de principe de la possibilité d’utiliser leurs propriétés dans des architectures supramoléculaires plus sophistiquées. Des expériences de compétition et d’échange ont complété cette étude qui prouve la possibilité d’utiliser ces systèmes en CDC. Il s’agit de la première utilisation de la chimie de Diels- Alder dans ce contexte. La recherche de nouveaux systèmes a été poursuivie pour comprendre les éléments structuraux qui génèrent ce caractère dynamique. En nous inspirant de la réaction réversible entre les anthracènes et les fullerènes, nous avons découvert des réactions de Diels-Alder équilibrées à température ambiante entre le 9,10-diméthylanthracène et les cyanooléfines utilisées avec les fulvènes. Les anthracènes présentent des propriétés de fluorescence, alors que leurs adduits de Diels-Alder ne les présentent plus : une commutation de la fluorescence par le contrôle de la position de l’équilibre a été étudiée. L’électrodéficience du groupement 1,1,2-tricyanoéthylène que nous avons décrit comme un diénophile très activé, est également responsable de son rôle d’accepteur d’électrons dans des molécules à transfert de charge interne. Les structures de type tricyanoéthynyléthylène ont montré une réactivité comme diénophiles dans des systèmes dynamiques mettant en jeu le 9,10-diméthylanthracène. Ces systèmes peuvent être vus comme des prototypes de commutation de propriétés d’optique non linéaire par la réaction de Diels-Alder. L’emploi de la réversibilité thermique de la réaction de Diels-Alder avait déjà été décrit pour la fabrication de polymères capables d’autoréparation. A haute température, une partie des adduits liant les monomères se défont, et renouent les chaînes des polymères au-delà de la cassure en se reformant quand la température diminue. Une limitation de ces systèmes est la température élevée (> 120°C) à laquelle se faisait jusqu’à présent la réa ction de rétro Diels-Alder. En se basant sur la réaction dynamique dès la température ambiante entre les fulvènes et les cyanooléfines que nous avons décrite, nous avons recherché l’obtention de polymères dynamiques à température ambiante avec des monomères fonctionnalisés par ces motifs. La preuve de la formation de polymères a été obtenue en solution par diffraction de neutrons. Des films minces de polymères ont aussi été obtenus. Des variations dans leurs structures ont permis d’obtenir des films souples et élastiques. Pour ceux-ci, des expériences d’autoréparation rapide à température ambiante ont été effectuées. D’un point de vue synthétique, l’obtention des diénophiles très activés a représenté un défi pour trouver des conditions permettant leurs purifications, celles précédemment publiées n’étant pas compatibles avec le développement de systèmes plus complexes qui sont décrits dans ce travail.
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Lacerda, Paula Sofia Sarrico. "Porfirinas como dienófilos em reacções de diels-alder." Master's thesis, Universidade de Aveiro, 1998. http://hdl.handle.net/10773/18279.
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Mestrado em Química de Produtos Naturais e AlimentosA presente dissertação encontra-se dividida em três partes: uma de índole introdutória, outra onde se apresentam e discutem os resultados obtidos e finalmente, uma parte onde se descrevem todos os procedimentos experimentais efectuados. Na primeira parte, de carácter geral, começamos por referir algumas características gerais das reacções de Diels-Alder, nomeadamente ao nível da reactividade. Devido ao papel crucial dos o-quinodimetanos no trabalho experimental apresentado nesta dissertação, é também feita uma referência a sua importância em reacções de Diels-Alder e a alguns dos métodos disponíveis para gerar este tipo de intermediários. Os compostos porfírínicos ocupam, nesta dissertação, um lugar de destaque pelo que neste capítulo também abordamos algumas características deste tipo de compostos. Depois de referirmos algumas características gerais ao nível da sua estrutura e reactividade, é feita também uma breve revis,ão das reacções de cicloadição de Diels-Alder envolvendo porfírias, descritas na literatura. Por fim, referimos uma das mais promissoras aplicações de compostos porfíícos no campo da medicina, a Terapia Fotodinâmica do cancro, onde estes compostos são utilizados como fotossensibilizadores. Na segunda parte desta dissertação, descrevem-se os métodos e resultados obtidos na síntese e a caracterização dos novos compostos porfirínicos obtidos a partir da transformação de várias porfirinas segundo a reacção de cicloadição de Diels-Alder. Mostra-se aqui, pela primeira vez, que o macrociclo porfirínico pode participar como dienófilo em reacções de Diels-Alder. Foram utilizadas várias meso-arilporfírinas, e como dienos utilizámos o o-benzoquinodimetano e dois pirimidino-o-quinodimetanos. Esta reacção permite a formação, num só passo, de nafto[2,3-blporfirias, clorinas e bactenoclorinas. Estes dois últimos tipos de compostos apresentam características espectroscópicas que tornam possível o seu uso como fotossensibilizadores de segunda geração para a Terapia Fotodinâmica do cancro. Na Última parte são descritas pormenorizadamente todas as experiências efectuadas e as características espectroscópicas, nomeadamente de espectcofotometria de UV-Vis, espectrometria de massa e espectroscopia de RMN, dos compostos sintetizados.
The work presented in this thesis is based on the use of meso-arylporphyrins as dienophiles in Diels-Alder reactions. It has been shown that nzeso-arylporphyrins react with ortho-quinodimethanes to give Diels-Alder adducts. The reaction of several meso-tetraarylporphyrins with o-benzoquinodimethane, generated in situ by thermal ekation of SOz fiam 1,3-dihydrobenzo[c]thiophene-2,2-dioxide was shidied. The main products of the reactions were identified as 2,21,26,3-tetrahydronaphtho[2,3-b]porphs(c hlorins), 21,26-dihydronaphtho[2,3-b]porphyrins and naphtho[2,3-blporphy~ins. When meso-tetra(pentduorophenyl)porphyrjn was used as dienophile, bis-addition was also observed and the adducts were identified as bacteriochlorins. This study was extended to 5,15-diarylporphyrins and to other o-quinodimethanes. Similar results were also obtained in these cases. Considering the UV-Vis spectra of some of these new products, we can expect that they are potential candidates to be used as photosensitiwrs in Photodynamic Therapy of cancer. All the synthesized compounds were characterked by nuclear magnetic resonance, mass spectromem and UV-Vis.
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Chahal, Jasprit Kaur. "Applications of imino-Diels-Alder reactions in synthesis." Thesis, Imperial College London, 2012. http://hdl.handle.net/10044/1/9524.
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The aim of the project was to synthesise (−)-morphine utilising a tethered intramolecular imino-Diels–Alder reaction. This thesis begins by providing brief reviews on the subjects of total synthesis of morphine and asymmetric imino-Diels–Alder reaction. The major section focuses on the research findings in the past four years. Starting with investigations in the development of a novel stereoselective imino-Diels–Alder reaction of methyl propargyl ether derived (1E,3Z)-1-silyloxy-3-(phenylthio)-1,3- dienes with trans-2-phenylcyclohexyl glyoxylate derived N-tosylimine. Following with the progress made so far to synthesise triene II; this was envisaged to be prepared from the enantiomerically pure alcohol III and allylic halide IV. The alcohol III was prepared in a five-step sequence from p-anisaldehyde. However, the synthesis of the allylic halide IV from D-lyxose was more challenging and problematic. Initial efforts for its synthesis via a route incorporating the Ohira–Bestmann reaction caused an unwanted epimerisation. Further efforts, through an eleven-step sequence including Wittig dibromomethylenation and intramolecular ene–yne metathesis gave V or VI. However, the reductive eliminations to give the alcohol precursor to IV were unsuccessful. [Molecular structure diagrams appear here. To view, please open pdf attachment]. Experimental details and characterisation data are provided at the end of the thesis.
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Reutenauer, Philippe Lehn Jean-Marie. "Réactions de Diels-Alder et chimie dynamique constitutionnelle." Strasbourg : Université Louis Pasteur, 2007. http://eprints-scd-ulp.u-strasbg.fr:8080/756/01/REUTENAUER2006.pdf.
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Lubin-Germain, Nadège. "Etude des reactions de diels-alder et hetero diels-alder en phase aqueuse. Synthese de l'acide 3-desoxy octulosonique (kdo) et d'analogues." Paris 11, 1992. http://www.theses.fr/1992PA112291.
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Apres avoir decrit la synthese du (2s), (3e)-hexa-3,5-diene-1,2-diol, chiral, soluble dans l'eau et constituant le materiel de depart de la synthese du kdo, nous avons etudie sa cycloaddition avec l'acroleine en phase aqueuse. L'eau est responsable de l'augmentation de la selectivite faciale si, requise pour la synthese du kdo, et de l'acceleration de la reaction. L'etude de cycloadditions en phase aqueuse a ete etendue a l'utilisation de dienophiles carbonyles, conduisant a des butyrolactones precurseurs de composes naturels. Enfin, nous decrivons la synthese rapide de l'acide 3-desoxy-d-manno-octulosonique (kdo): les etapes ont ete mises au point sur un diene modele conduisant a des analogues de l'acide 3-desoxy-d-arabino-heptulosonique; la strategie de synthese permet d'obtenir le kdo sous forme activee pour d'eventuelles glycosylations, et des analogues, inhibiteurs potentiels d'enzymes impliques dans la biosynthese du lps
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Barbosa, Jader da Silva. "Estudo sobre a síntese de furanoliangolidos pela Reação de Diels-Alder." Universidade de São Paulo, 2010. http://www.teses.usp.br/teses/disponiveis/59/59138/tde-08062010-185911/.
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Nosso grupo de pesquisa já vem há alguns anos estudando métodos para a síntese do núcleo estrutural dos furanoeliangolidos, mais especificamente do goiazensolido. A estrutura básica deste composto corresponde a um sistema 7-oxabiciclo [6.2.1] undecano, e ele possui atividades biológicas como esquistossomicida, citotóxica e antiinflamatória. Em nosso trabalho utilizamos como etapa chave a reação de Diels-Alder, que é geralmente eficiente e rápida para formação de sistemas policíclicos. Na ultima etapa da proposta sintética, propomos a clivagem da ligação interna do sistema policíclico para obtenção do macrociclo desejado.Our research group has been studying, for some years, new methods for the synthesis of the core structure of the furanoheliangolides, more specifically of goyazensolide. The basic structure of this compound is a 7-oxabicyclo [6.2.1] undecane system, and it shows biological activities such as schistosomicidal, cytotoxic and anti-inflammatory. In this work, we have used the Diels-Alder reaction as a key step, since it is usually fast and efficient for the synthesis of polycyclic structures. As a last step, we proposed that the cleavage of the internal bond of the rings should furnish the desired macrocycle.
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Chumachenko, Natasha. "[Beta]-acryloyloxysulfonyl tethers for intramolecular Diels-Alder cycloaddition reactions." [Kent, Ohio] : Kent State University, 2005. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=kent1135392557.
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Thesis (Ph.D.)--Kent State University, 2005.Title from PDF t.p. (viewed July 28, 2005). Author's first name appears on the abstract page as: Nataliya. Advisor: Paul Sampson. Keywords: b-hydroxysulfones; [beta]-hydroxysulfones; epoxide opening; intramolecular Diels-Alder reaction; vinylsulfones. Includes bibliographical references (p.194- 202).
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Zerwes, Ludger. "Untersuchungen zur Stereoselektion in einer Photo-Diels-Alder-Cycloaddition." [S.l. : s.n.], 2005. http://deposit.ddb.de/cgi-bin/dokserv?idn=973887664.
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Linder, Mats. "Computational Studies and Design of Biomolecular Diels-Alder Catalysis." Doctoral thesis, KTH, Tillämpad fysikalisk kemi, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-101706.
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The Diels-Alder reaction is one of the most powerful synthetic tools in organic chemistry, and asymmetric Diels-Alder catalysis allows for rapid construction of chiral carbon scaffolds. For this reason, considerable effort has been invested in developing efficient and stereoselective organo- and biocatalysts. However, Diels-Alder is a virtually unknown reaction in Nature, and to engineer an enzyme into a Diels-Alderase is therefore a challenging task. Despite several successful designs of catalytic antibodies since the 1980’s, their catalytic activities have remained low, and no true artificial ’Diels-Alderase’ enzyme was reported before 2010. In this thesis, we employ state-of-the-art computational tools to study the mechanism of organocatalyzed Diels-Alder in detail, and to redesign existing enzymes into intermolecular Diels-Alder catalysts. Papers I–IV explore the mechanistic variations when employing increasingly activated reactants and the effect of catalysis. In particular, the relation between the traditionally presumed concerted mechanism and a stepwise pathway, forming one bond at a time, is probed. Papers V–X deal with enzyme design and the computational aspects of predicting catalytic activity. Four novel, computationally designed Diels-Alderase candidates are presented in Papers VI–IX. In Paper X, a new parameterization of the Linear Interaction Energy model for predicting protein-ligand affinities is presented. A general finding in this thesis is that it is difficult to attain large transition state stabilization effects solely by hydrogen bond catalysis. In addition, water (the preferred solvent of enzymes) is well-known for catalyzing Diels- Alder by itself. Therefore, an efficient Diels-Alderase must rely on large binding affinities for the two substrates and preferential binding conformations close to the transition state geometry. In Papers VI–VIII, we co-designed the enzyme active site and substrates in order to achieve the best possible complementarity and maximize binding affinity and pre-organization. Even so, catalysis is limited by the maximum possible stabilization offered by hydrogen bonds, and by the inherently large energy barrier associated with the [4+2] cycloaddition. The stepwise Diels-Alder pathway, proceeding via a zwitterionic intermediate, may offer a productive alternative for enzyme catalysis, since an enzyme active site may be more differentiated towards stabilizing the high-energy states than for the standard mechanism. In Papers I and III, it is demonstrated that a hydrogen bond donor catalyst provides more stabilization of transition states having pronounced charge-transfer character, which shifts the preference towards a stepwise mechanism. Another alternative, explored in Paper IX, is to use an α,β -unsaturated ketone as a ’pro-diene’, and let the enzyme generate the diene in situ by general acid/base catalysis. The results show that the potential reduction in the reaction barrier with such a mechanism is much larger than for conventional Diels-Alder. Moreover, an acid/base-mediated pathway is a better mimic of how natural enzymes function, since remarkably few catalyze their reactions solely by non-covalent interactions.QC 20120903