Log in

Relevant bibliographies by topics / Alkany / Dissertations / Theses

To see the other types of publications on this topic, follow the link: Alkany.

Dissertations / Theses on the topic 'Alkany'

Author: Grafiati

Published: 4 June 2021

Last updated: 25 April 2022

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles

Select a source type:

Consult the top 50 dissertations / theses for your research on the topic 'Alkany.'

Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.

You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.

Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.

1

Mahelová, Zora. "Charakterizace chemického složení dehtu po zplyňování biomasy." Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2016. http://www.nusl.cz/ntk/nusl-240964.

Full text

Abstract:

Biomass is a renewable source of energy and represents an acceptable alternative to fosil fuels. Usable methods of energetic use of biomass are combustion and gasification. Main interest is focused on gasification in last years. Gasification is based on conversion of organic material to usable gaseous product called syngas, which can be used as a fuel for energy production. Large amount of tar is formed as a by-product of incineration and gasification of biomass. Tar is composed by various mixture of organic substances, has a negative effect on operating conditions and is a potential threat to environment. Experimental part of this study was focused on analysis of tar obtained by gasification of various kind of biomass. Selected groups of hydrocarbons and oxygen compounds were identified in analysed samples. Individual biomass samples were compared regarding to determined relative content of selected substances. Analysis was done by complete twodimensional gas chromatography with mass spectrometric detection (GCxGC/TOF-MS).

APA, Harvard, Vancouver, ISO, and other styles

2

Peter, Sebastian. "Oxyfunctionalization of alkanes, alkenes and alkynes by unspecific peroxygenase (EC 1.11.2.1)." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2013. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-113321.

Full text

Abstract:

Unspecific peroxygenase (EC 1.11.2.1) represents a group of secreted hemethiolate proteins that are capable of catalyzing the selective mono-oxygenation of diverse organic compounds using only H2O2 as a cosubstrate. In this study, the peroxygenase from Agrocybe aegerita (AaeUPO) was found to catalyze the hydroxylation of various linear (e.g n-hexane), branched (e.g. 2,3-dimethylbutane) and cyclic alkanes (e.g. cyclohexane). The size of n-alkane substrates converted by AaeUPO ranged from gaseous propane (C3) to n-hexadecane (C16). They were mono-hydroxylated mainly at the C2 and C3 position, rather than at the terminal carbon, and the corresponding ketones were formed as a result of overoxidation. In addition, a number of alkenes were epoxidized by AaeUPO, including linear terminal (e.g. 1-heptene), branched (2-methyl-2-butene) and cyclic alkenes (e.g. cyclopentene), as well as linear and cyclic dienes (buta-1,3-diene, cyclohexa-1,4-diene). Furthermore, the conversion of terminal alkynes (e.g. 1- octyne) gave the corresponding 1-alkyn-3-ol in low yield. Some of the reactions proceeded with complete regioselectivity and - in the case of linear alkanes, terminal linear alkenes and alkynes - with moderate to high stereoselectivity. The conversion of n-octane gave (R)-3-octanol with 99% enantiomeric excess (ee) and the preponderance of the (S)-enantiomer reached up to 72% ee of the epoxide product for the conversion of 1-heptene. Catalytic efficiencies (kcat/ Km) determined for the hydroxylation and respectively epoxidation of the model compounds cyclohexane and 2-methyl-2-butene were 2.0 × 103 M-1 s-1 and 2.5 × 105 M−1 s−1. The results obtained in the deuterium isotope effect experiment with semideuterated n-hexane and the radical clock experiment with norcarane clearly demonstrated that the hydroxylation of alkanes proceeds via hydrogen abstraction, the formation of a substrate radical and a subsequent oxygen rebound mechanism. Moreover, stopped-flow experiments and substrate kinetics proved the involvement of a porphyrin radical cation species (compound I; AaeUPO-I) as reactive intermediate in the catalytic cycle of AaeUPO, similar to other hemethiolate enzymes (e.g. cytochrome P450 monooxygenases, P450s)
Die Gruppe der Unspezifischen Peroxygenasen (EC 1.11.2.1) umfasst extrazelluläre Häm-Thiolat-Enzyme, die mittels H2O2 als Cosubstrat die selektive Monooxygenierung unterschiedlicher organischer Verbindungen katalysieren. In der vorliegenden Arbeit konnte gezeigt werden, dass die von Agrocybe aegerita sekretierte Peroxygenase (AaeUPO) verschiedene lineare (z. B. n-Hexan), verzweigte (z. B. 2,3-Dimethylbutan) und zyklische Alkane (z. B. Cyclohexan) hydroxyliert. Die Größe der von der AaeUPO umgesetzten Substrate reichte vom gasförmigen Propan (C3) bis hin zu n-Hexadekan (C16). Die Alkane wurden bevorzugt am zweiten und dritten Kohlenstoffatom (C2 und C3) hydroxyliert; eine Hydroxylierung am terminalen Kohlenstoff konnte nur vereinzelt und in geringem Umfang beobachtet werden. Die Überoxidationen der primär gebildeten, sekundären Alkohole führte außerdem zur Entstehung der entsprechenden Ketonderivate. Darüber hinaus wurde eine Vielzahl linearer terminaler (z. B. 1-Hepten), verzweigter (z. B. 2-Methyl-2-Buten) und zyklischer Alkene (z. B. Cyclopenten) sowie linearer und zyklischer Diene (1,3-Butadien, 1,4-Cyclohexadien) durch die AaeUPO epoxidiert. Die Umsetzung terminaler Alkine (z. B. 1-Octin) führte zur Entstehung der jeweiligen 1-Alkin-3-ole. Manche dieser Reaktionen verliefen ausgeprägt regioselektiv und, im Falle der linearen Alkane sowie der linearen terminalen Alkene und Alkine, mit mittlerer bis hoher Stereoselektivität. So ergab beispielsweise die Umsetzung von n-Octan einen Enantiomerenüberschuss größer 99% für (R)-3-Octanol; die Epoxidierung von 1-Hepten lieferte einen Enatiomeerenüberschuss (ee) von bis zu 72% für das (S)-Enantiomer. Die katalytischen Effizienzen, die für die Hydroxylierung bzw. Epoxidierung der Modellverbindungen Cyclohexan und 2-Methyl-2-Buten ermittelt wurden, betragen 2.0 × 103 M-1 s-1 und 2.5 × 105 M−1 s−1. Der ausgeprägte Deuterium-Isotopen-Effekt, der im Zuge der Umsetzung von semideuteriertem n-Hexan beobachtet wurde sowie die Ergebnisse des Radical-Clock-Experiments mit Norcarane als Substrat bestätigten, dass die Hydroxylierung von Alkanen über Wasserstoffabstraktion, die Bildung eines Substratradikals und anschließende direkte Sauerstoffrückbindung verläuft. Die Stopped-Flow-Experimente belegen zudem das Auftreten eines Porphyrin-Kationradikal-Intermediates (Compound I; AaeUPO-I) im katalytischen Zyklus der AaeUPO (vergleichbar mit dem reaktiven Intermediat der P450-Monooxygenasen)

APA, Harvard, Vancouver, ISO, and other styles

3

Haak, Edgar. "Titankatalysatoren für die intermolekulare Hydroaminierung von Alkinen und Alkenen." [S.l. : s.n.], 2002. http://deposit.ddb.de/cgi-bin/dokserv?idn=964517639.

Full text

APA, Harvard, Vancouver, ISO, and other styles

4

George, Darren Shawn Allen. "Alkyne and alkynyl complexes of rhodium and iridium." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape7/PQDD_0025/NQ39530.pdf.

Full text

APA, Harvard, Vancouver, ISO, and other styles

5

Groaz, Elisabetta. "Alkene and alkyne metathesis reactions using ruthenium initiators." Thesis, King's College London (University of London), 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.440449.

Full text

APA, Harvard, Vancouver, ISO, and other styles

6

Wang, Ruiping. "Indenyl nickel complexes bearing alkynyl, alkenyl and triflate ligands." [Montréal] : Université de Montréal, 2003. http://wwwlib.umi.com/cr/umontreal/fullcit?pNQ82764.

Full text

Abstract:

Thèse (Ph. D.)--Université de Montréal, 2003.
"NQ-82764." "Thèse présentée à la faculté des études supérieures en vue de l'obtention du grade de philosophiae doctor (Ph. D.) en chimie." Version électronique également disponible sur Internet.

APA, Harvard, Vancouver, ISO, and other styles

7

Mehta, Brinda Mayank. "Green Resins based on Alkene- and Alkyne-containing Triglycerides." University of Akron / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=akron1468795161.

Full text

APA, Harvard, Vancouver, ISO, and other styles

8

Shoai, Shiva. "Regioselective rhodium-catalyzed alkyne hydrothiolation with alkane thiols : substrate scope and mechanistic investigations." Thesis, University of British Columbia, 2010. http://hdl.handle.net/2429/27028.

Full text

Abstract:

The optimization and substrate scope of ClRh(PPh₃)₃-catalyzed alkyne hydrothiolation with alkane thiols producing E-linear vinyl sulfides is presented. The reactions generally proceed in good yields with good selectivities for a variety of alkane thiols and alkynes. Bulky aliphatic alkynes result in the best selectivity, while aryl alkynes with para-substituted electron donating groups give the best yields. The presence of coordinating functional groups in either the substrate or solvent negatively affects the reaction both in yield and selectivity. Deuterium-labeling studies indicate that the reaction proceeds via thiol oxidative addition, migratory alkyne insertion into the Rh-H bond, followed by reductive elimination. Investigations into the mechanism of Tp*Rh(PPh₃)₂-catalyzed alkyne hydrothiolation are discussed. Five mechanisms are identified as being the most likely for this process; experiments were designed to support or refute each of these possibilities. Two mechanisms are definitively dismissed and another is dismissed as highly unlikely. The results cannot distinguish between the remaining two. The product distribution of hydrothiolation is analyzed and compared to other precatalysts. Stoichiometric reactivity of Tp*Rh(PPh₃)₂ with benzyl thiol is presented. Two new complexes, proposed to be Tp*Rh(PPh₃)₂(HSBn) and Tp*Rh(H)(SBn)(PPh₃), are generated. Presumed Tp*Rh(H)(SBn)(PPh₃), prepared in situ, does not catalyze alkyne hydrothiolation. Kinetic analysis was complicated by reaction inhibition at high thiol concentrations and competing side-reactions at high alkyne concentrations. Kinetic isotope effect experiments indicate that the alkyne is not involved in the rate-determining step; however, differences in the reactivity of several para-substituted phenyl acetylenes suggest that the rate-determining step is influenced by alkyne electronics. Overall, the reaction appears to obey the following rate law under normal catalytic reaction conditions rate = k[Tp*Rh(PPh₃)₂]¹[thiol]¹[alkyne]⁰. The reaction is hypothesized to proceed by thiol oxidative addition, migratory alkyne insertion into the Rh-S bond, followed by reductive elimination.

APA, Harvard, Vancouver, ISO, and other styles

9

Lamberto, Massimiliano. "Thiol mediated radical cyclisations of isocyanides : synthesis of #NU# heterocycles." Thesis, University of Southampton, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.289909.

Full text

APA, Harvard, Vancouver, ISO, and other styles

10

ZHENG, TAO. "MOLECULAR SIMULATION OF DIFFUSION AND SORPTION OF ALKANES AND ALKANE MIXTURES IN POLY[1-(TRIMETHYLSILYL)-1-PROPYNE]." University of Cincinnati / OhioLINK, 2000. http://rave.ohiolink.edu/etdc/view?acc_num=ucin973701057.

Full text

APA, Harvard, Vancouver, ISO, and other styles

11

Grasso, Giuseppe. "Solid-state NMR studies of alkali fullerides and long-chain alkanes." Thesis, University of Nottingham, 2004. http://eprints.nottingham.ac.uk/10051/.

Full text

Abstract:

The main focus of this thesis is the investigation of structure and motion of different materials by applying different solid-state NMR techniques. In the first section (1) some of the bases of NMR are described both in a Classical (1.1) and Quantum Mechanical (1.2) approach, while the next two sections deal with the experimental part of the work. In section 2 solid-state NMR studies of CsC60 are described and an unambiguous assignment of the 13C NMR spectrum of the polymer phase of CsC60, which is based solely on our experimental data, is presented. In contrast to previous work, the assignment does not rely on the knowledge of the electronic structure of this material and our results support a fully three-dimensional electronic structure as opposed to a quasi one-dimensional one. This is achieved using a two-dimensional 13C MAS NMR correlation experiment, which identifies nuclei coupled via a through-bond scalar interaction, the Refocused INADEQUATE. In section 3 solid-state NMR experiments performed on polyethylene and long-chain n-alkanes corresponding to the formula C246H494 are described. Particular attention is given to some specific issues such as chain folding and a detailed study of the saturation-recovery curves (T1) obtained is carried out for different materials. The model elaborated is able to simulate all the data recorded and the presence of an interphase between the crystalline and the amorphous parts of the samples is proposed. To help the understanding of the structure and the motion of long-chain n-alkanes in section 3 some deuterated samples such as C216H434-d24 and C12H25(CH2)192CHDC11D23+C162H326 ("the mixture") are also studied. Deuterium NMR is widely used and we fit all the experimental line shape of the different samples at different temperatures. Diverse models for the structure and motion of such materials are given, which take into account all the experimental results obtained.

APA, Harvard, Vancouver, ISO, and other styles

12

Žvaková, Veronika. "Detailní charakterizace pyrolýzního oleje pomocí separačních technik a hmotnostní spektrometrie." Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2017. http://www.nusl.cz/ntk/nusl-316220.

Full text

Abstract:

The aim of this work is detailed characterization of pyrolysis oil by advanced analytical separation methods and mass spectrometry. During the pyrolysis process decomposition of complex organic material take place in the presence of high temperatures and the absence of oxygen. Condensable part of vapours and aerosols forms viscous liquid called pyrolysis oil which is a complex mixture of large amount of compounds. In this work samples from microwave pyrolysis of woodchips and sewage sludge from wastewater treatment plant Brno-Modřice were analysed. Samples were provided by Bionic Laboratories company. Samples were separated by column chromatography on activated silica. For detailed characterization of each fraction gas chromatography with mass spectrometry detection and comprehensive two-dimensional gas chromatography with mass spectrometric detection with time of flight analyser were used. Substances that have been identified can be divided into several groups: alkanes, alkenes, aromatic hydrocarbons, polycyclic aromatic hydrocarbons, alcohols, aldehydes, esters, carboxylic acid and heterocycles.

APA, Harvard, Vancouver, ISO, and other styles

13

Yip, Wing-ping, and 葉永平. "Alkane C-H bond oxidations and alkene dihydroxylations by oxorutheniumcomplexes of chelating tertiary amine ligands." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2004. http://hub.hku.hk/bib/B31246254.

Full text

APA, Harvard, Vancouver, ISO, and other styles

14

Naohisa, Nakagawa. "Selective Synthesis of Alkynes and Alkenes Using Iron-Catalyzed Cross-Coupling and Organometallic Addition Reactions." 京都大学 (Kyoto University), 2015. http://hdl.handle.net/2433/200444.

Full text

APA, Harvard, Vancouver, ISO, and other styles

15

Wagener, Alex [Verfasser], and Stefan [Akademischer Betreuer] Ernst. "Adsorptive Trennung von Gemischen kurzkettiger Alkane und Alkene an nanostrukturierten porösen Adsorbentien / Alex Wagener. Betreuer: Stefan Ernst." Kaiserslautern : Universitätsbibliothek Kaiserslautern, 2012. http://d-nb.info/1021529036/34.

Full text

APA, Harvard, Vancouver, ISO, and other styles

16

Hunt, Ashley D. "Intramolecular Cope-type Hydroamination of Alkenes and Alkynes Using Hydrazides." Thèse, Université d'Ottawa / University of Ottawa, 2011. http://hdl.handle.net/10393/19881.

Full text

Abstract:

Nitrogen-containing molecules are ubiquitous in both natural products and pharmaceutical drugs, thus an efficient method for the formation of these motifs is of great importance. Hydroamination, that is the addition of an N-H bond across an unsaturated carbon-carbon bond of an alkene or alkyne, stands out as a potential approach to obtain such molecules. To date, most research in this area relies on transition-metal catalysis to enable such reactivity. In efforts directed towards metal-free alternatives, we have developed a simple, metal-free hydroamination of alkenes using hydrazides. Further investigation into the corresponding reactivity of alkynes with hydrazides has provided access to novel azomethine imine products. In Chapter 2, expansion of the substrate scope with respect to the intramolecular hydroamination of alkenes using hydrazides, as well as studies directed towards elucidation of the mechanism of this reaction will be presented. The intramolecular hydroamination of alkynes using hydrazides and methods to access and isolate the azomethine imine products formed will be discussed in Chapter 3.

APA, Harvard, Vancouver, ISO, and other styles

17

Correia, Leslie Daniel Camara. "Oxygen transfer in hydrocarbon-aqueous dispersions and its applicability to alkane-based bioprocesses." Thesis, Link to the online version, 2007. http://hdl.handle.net/10019/999.

Full text

APA, Harvard, Vancouver, ISO, and other styles

18

Criswell, Leah. "Neutron diffraction and quasielastic neutron scattering studies of films of N-alkanes and a branched alkane absorbed on graphite." Diss., Columbia, Mo. : University of Missouri-Columbia, 2007. http://hdl.handle.net/10355/6010.

Full text

Abstract:

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 March 11, 2008) Includes bibliographical references.

APA, Harvard, Vancouver, ISO, and other styles

19

Peters, Dietmund. "Homoaromatische Nickel(0)-Alken- und Alkin-Komplexe computergestützte Optimierung, Synthese und Eigenschaften /." [S.l.] : [s.n.], 2005. http://e-diss.uni-kiel.de/diss_1684/d1684.pdf.

Full text

APA, Harvard, Vancouver, ISO, and other styles

20

Régent, Damien [Verfasser], and Bernhard [Akademischer Betreuer] Breit. "Rhodium-catalyzed intra- and intermolecular alkene hydroacylation = Rhodium-katalisierte Intra- und Intermolecular Alken Hydroacylation." Freiburg : Universität, 2014. http://d-nb.info/1115813811/34.

Full text

APA, Harvard, Vancouver, ISO, and other styles

21

Rode, Katharina. "Studies Toward Selenium-pi-Acid Catalyzed Oxidative Functionalizations of Olefinic and Acetylenic Multiple Bonds." Doctoral thesis, Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2020. http://hdl.handle.net/21.11130/00-1735-0000-0005-1491-0.

Full text

APA, Harvard, Vancouver, ISO, and other styles

22

Prat, Casellas Irene. "Bioinspired non-heme iron catalysts for challenging oxidative transformations: mechanistic studies and catalytic applications on selective alkane hydroxylation and alkene cis-dihydroxilation." Doctoral thesis, Universitat de Girona, 2013. http://hdl.handle.net/10803/117778.

Full text

Abstract:

The functionalization of hydrocarbons in a sustainable manner is one of the main challenges for chemists. Their abundance in nature as natural gas or crude oil makes them the most convenient chemical feedstock. The oxidation of hydrocarbons is one of the most interesting reactions, because the introduction of an oxygen atom introduces functionality in these molecules, increasing their value as reagents for further chemical transformation. However, these reactions are fundamentally difficult due to the low reactivity of alkyl C-H bonds. Current available methodologies involve highly reactive-oxidizing reagents, high temperatures and long-time reactions in order to overcome this lack of reactivity. These harsh conditions introduce drawbacks in terms of chemo- and regioselectivity, essential to produce synthetic valuable products. An important step forward is the development of one-step oxidation methodologies, allowing the oxidation of C-H and C=C with high regio- and stereoselectivity. Natural systems, such as iron enzymes, are capable of perform this chemistry with high selectivity and efficiency. Iron is the most abundant metallic element in the earth and is essential for live. In addition, this lack of toxicity makes it and attractive material to substitute more toxic and expensive metals currently used. One of the main objective of this thesis is design of iron complexes that mimics the structure and function of these natural enzymes with the aim of find new methodologies for the selective C-H and C=C bond oxidation using green conditions. Furthermore, the study of these compounds could give useful information about the oxidation mechanisms operating in oxygenase enzymes. The results obtained in this thesis clarify the mechanism by which the oxidation of the C-H bond with retention of stereochemistry takes place at a mononuclear non-heme iron site, and evidence the formation of a high valent iron (V) capable of perform the cis-dihydroxylation of alkenes. Furthermore, a new complex is described as an efficient and selective catalyst capable of performing this chemistry in a scale amenable for synthetic applications
La funcionalització d'hidrocarburs de manera sostenible i eficaç és un dels principals reptes per la química moderna, degut a que la seva abundància natural els fa una important matèria primera. L'oxidació d'hidrocarburs és una de les reaccions més interessants, ja que la introducció d’un àtom d’oxigen en l’estructura d’un hidrocarburs li confereix funcionalitat química, fa augmentar el seu valor i els converteix en reactius adients per subseqüents transformacions químiques. No obstant això, aquestes reaccions són difícils a causa de la inherent baixa reactivitat dels hidrocarburs. Les metodologies actualment disponibles impliquen la utilització d’espècies altament oxidants i tòxiques, altes temperatures i llargs temps de reacció per tal de superar aquesta manca de reactivitat. Aquestes condicions extremes eviten que la química es pugui dur a terme de manera selectiva, fet essencial per produir productes d’alt valor sintètic. Un avanç important és el desenvolupament de metodologies de reacció suaus que permetin l'oxidació d'enllaços C-H i C=C amb alta regio- i estereoselectivitat. Els sistemes naturals, com ara enzims de ferro, són capaços de realitzar aquesta química. El ferro és l’element metàl•lic més abundant a la terra i és clau per nombrosos processos vitals, a més la seva baixa toxicitat el fa un atractiu material per substituir els elements de segona i tercera seria de transició més cars i tòxics emprats actualment. Un dels principals objectius d’aquesta tesi és dissenyar catalitzadors de ferro que imiten l’estructura i la funció dels enzims naturals per tal de trobar una nova metodologia que permeti l'oxidació selectiva d'enllaços C-H i C=C utilitzant condicions suaus i mediambientalment més benignes que les metodologies tradicionals. A més, l’estudi d’aquests sistemes pot donar informació útil sobre el mecanisme d’oxidació del propi enzim. Els resultats obtinguts en aquesta tesi aclareixen el mecanisme pel qual es duu a terme la hidroxilació de l’enllaç C-H amb retenció de la estereoselectivitat en centres mononuclears de ferro, i evidencien la formació d’una espècie de ferro (V) d’alt estat d’oxidació capaç de catalitzar la cis-dihidroxilació d’alquens. A més a més, es descobreix un catalitzador eficient i selectiu capaç de dur a terme aquesta química en condicions d’escala preparativa

APA, Harvard, Vancouver, ISO, and other styles

23

Imbert, F. E. "Aspects of alkane decomposition." Thesis, Swansea University, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.637369.

Full text

APA, Harvard, Vancouver, ISO, and other styles

24

Weiguo, Shen. "Thermodynamics of alkane solutions." Thesis, University of Canterbury. Chemical and Process Engineering, 1988. http://hdl.handle.net/10092/7727.

Full text

Abstract:

An apparatus for static vapour pressure measurements on pure liquids and on binary and ternary mixtures containing one involatile component has been designed and constructed. The apparatus and corresponding experimental techniques have been tested and experimental errors have been discussed. Measurements have been made of the vapour pressures of binary mixtures of n-hexane + n-hexadecane at 298.15 K and 303.15 K and of binary mixtures of n-hexane + n-octane, n-octane + n-hexadecane, and ternary mixtures of n-hexane + n-octane + n-hexadecane at 298.15 K. The experimental measurements of pressures (P) vs mole fractions (x) have been fitted to the Redlich-Kister equation by Barker's method to obtain activity coefficients of each component in the liquid phase, the excess Gibbs functions, and the mole fractions in the vapour phase. The results for n-hexane + n-hexadecane at 303.15 K have been compared with those of previous work (Williamson, 1957) and the agreement is reasonably good. The excess volumes of n-hexane +benzene, n-dodecane + 2-methylpentane and pseudo n-dodecane prepared from equimolar numbers of n-decane + n-tetradecane + each of four branched hexane isomers at 298.15 K have been obtained from measurements of the densities of pure compounds and mixtures with a vibrating tube densimeter. Two methods for preparation of mixtures of which densities are required to be accurately measured have been designed and compared with each other. The excess enthalpies of 2-methylpentane with n-dodecane and with each of three pseudo n-dodecanes prepared from equimolar mixtures of n-decane + n-tetradecane, n-undecane + n-tridecane, and n-octane + n-hexadecane, and the excess enthalpies of equimolar decane + tetradecane mixture with each of the other three branched hexane isomers at 298.15 K have been measured with an isothermal displacement calorimeter. The experimental results of binary mixtures have been discussed in term of the principle of congruence with Hijmans' graphical method and Bellemans and Mat's analytical formula. New graphical tests of the principle of congruence and a modified Bellemans and Mat equation for ternary mixtures have been developed and applied to the experimental p-x data of ternary systems. The agreement between the experimental values and those predicted by the principle are excellent. The modified Bellemans and Mat equation seems to be more powerful than and preferable to the Redlich-Kister equation for the systems investigated in this work.

APA, Harvard, Vancouver, ISO, and other styles

25

Calderone, Joseph Anthony III. "Borylations and Silylations of Alkenyl and Alkynyl Carbonyl Compounds Employing a Mild and Environmentally Friendly Cu(II) Catalyst." Thesis, Virginia Tech, 2014. http://hdl.handle.net/10919/47723.

Full text

Abstract:

An environmentally friendly, operationally simple copper-amine catalyst system is disclosed. Using this catalyst system, electron deficient alkenes and alkynes with diverse functional groups are borylated and silylated in high yields and with short reaction times. In the case of electron deficient alkynes the identity of the electron withdrawing group controlled diastereoselectivity. Esters and amides exclusively form E-product, while aldehydes and ketones favor Z-product. Mechanistic insights into the catalytic cycle as well as origin of diastereoselectivity are discussed.
Master of Science

APA, Harvard, Vancouver, ISO, and other styles

26

Okabayashi, Yohei. "Synthesis of azide- and alkyne-terminated alkane thiols and evaluation of their application in Huisgen 1,3-dipolar cycloaddition ("click") reactions on gold surfaces." Thesis, Department of Physics, Chemistry and Biology, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-20559.

Full text

Abstract:

Immobilization of different bio- and organic molecules on solid supports is fundamental within many areas of science. Sometimes, it is desirable to obtain a directed orientation of the molecule in the immobilized state. In this thesis, the copper (I) catalyzed Huisgen 1,3-dipolar cycloaddition, referred to as a “click chemistry” reaction, was explored as a means to perform directed immobilization of small molecule ligands on gold surfaces. The aim was to synthesize alkyne- and azide-terminated alkanethiols that would form well-organized self assembled monolayers (SAMs) on gold from the commercially available substances orthoethylene glycol and bromo alkanoic acid. N-(23-azido-3,6,9,12,15,18,21-heptaoxatricosyl)-n-mercaptododekanamide/hexadecaneamide (n = 12, 16) were successfully synthesized and allowed to form SAMs of different compositions to study how the differences in density of the functional groups on the surface would influence the structure of the monolayer and the click chemistry reaction. The surfaces were characterized by different optical methods: ellipsometry, contact angle goniometry and infrared reflection-absorption spectroscopy (IRAS). The click reaction was found to proceed at very high yields on all investigated surfaces. Finally, the biomolecular interaction between a ligand immobilized by click chemistry on the gold surfaces and a model protein (bovine carbonic anhydrase) was demonstrated by surface plasmon resonance using a Biacore system.

APA, Harvard, Vancouver, ISO, and other styles

27

Elser, Iris [Verfasser], and Michael R. [Akademischer Betreuer] Buchmeiser. "(Pre-)ionic and/or chiral alkene and alkyne metathesis catalysts of group 6 / Iris Elser ; Betreuer: Michael R. Buchmeiser." Stuttgart : Universitätsbibliothek der Universität Stuttgart, 2018. http://d-nb.info/1183678274/34.

Full text

APA, Harvard, Vancouver, ISO, and other styles

28

García, Ojeda José Luis [Verfasser], and Rudolf [Akademischer Betreuer] Müller. "Oxidation of long-chain n-alkanes by mutants of a thermophilic alkane-degrading bacterium: Thermus sp. ATN1 / José Luis García Ojeda. Betreuer: Rudolf Müller." Hamburg-Harburg : Universitätsbibliothek der Technischen Universität Hamburg-Harburg, 2014. http://d-nb.info/1048647358/34.

Full text

APA, Harvard, Vancouver, ISO, and other styles

29

Kleinschmidt, Olaf. "Photokatalytische Oxidation von Alkenen und Alkanen mit Sauerstoff an belichtetem Titandioxid." [S.l. : s.n.], 2001. http://deposit.ddb.de/cgi-bin/dokserv?idn=962781142.

Full text

APA, Harvard, Vancouver, ISO, and other styles

30

Weidinger, Inez Marita. "Untersuchungen zum Gefrierverhalten levitierter n-Alkan- Mikrotropfen." [S.l. : s.n.], 2003. http://www.diss.fu-berlin.de/2003/152/index.html.

Full text

APA, Harvard, Vancouver, ISO, and other styles

31

Szuromi, Endre. "Alkene-oxo and alkene-alkene coupling on Pt(II)." Diss., Columbia, Mo. : University of Missouri-Columbia, 2005. http://hdl.handle.net/10355/4156.

Full text

Abstract:

Thesis (Ph. D.)--University of Missouri-Columbia, 2005.
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 (November 14, 2006) Vita. Includes bibliographical references.

APA, Harvard, Vancouver, ISO, and other styles

32

Tóth, Krisztián [Verfasser], and Klaus T. [Akademischer Betreuer] Wanner. "Synthesis and biological evaluation of novel N-substituted nipecotic acid derivatives with an alkyne, trans-alkene or cis-alkene spacer as GABA uptake inhibitors / Krisztián Tóth ; Betreuer: Klaus T. Wanner." München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2018. http://d-nb.info/1177682087/34.

Full text

APA, Harvard, Vancouver, ISO, and other styles

33

Hooper, Andrew David. "Alkane hydrogenolysis on ruthenium catalysts." Thesis, Brunel University, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.302574.

Full text

APA, Harvard, Vancouver, ISO, and other styles

34

Newell, Helen E. "Alkane adsorption on metal surfaces." Thesis, University of Nottingham, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.243748.

Full text

APA, Harvard, Vancouver, ISO, and other styles

35

Huang, Zheng Brookhart Maurice S. "Alkane metathesis via tandem catalysis." Chapel Hill, N.C. : University of North Carolina at Chapel Hill, 2009. http://dc.lib.unc.edu/u?/etd,2576.

Full text

Abstract:

Thesis (Ph. D.)--University of North Carolina at Chapel Hill, 2009.
Title from electronic title page (viewed Oct. 5, 2009). "... in partial fulfillment of the requirements for the degree of Doctor of Philosophy in the Department of Chemistry." Discipline: Chemistry; Department/School: Chemistry.

APA, Harvard, Vancouver, ISO, and other styles

36

Bouyer, Maouen Abdelkarim. "Computer simulations of alkane-zeolite systems." Doctoral thesis, Universite Libre de Bruxelles, 1998. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/212049.

Full text

APA, Harvard, Vancouver, ISO, and other styles

37

Mallors, Ruth Louise. "Alkyne and alkyne-arene complexes of ruthenium." Thesis, University of Edinburgh, 1995. http://hdl.handle.net/1842/15261.

Full text

Abstract:

The introduction begins with an out-line of the cluster surface analogy and looks at the importance of studying small organic molecules on clusters to attain a greater understanding of metallic surfaces. The Chapter goes on to look at the activation of alkynes upon coordination to a cluster and assesses the diverse behaviour of alkynes as ligands, some electron counting considerations are considered. Reaction procedures employed in the synthesis of cluster-alkyne complexes are compared highlighting pros and cons of the different routes. The Chapter concludes with a brief synopsis on the cluster [Ru₆C(CO)₁₇]. Chapter two is concerned with the synthesis and characterisation of a series alkyne substituted hexaruthenium carbonyl complexes. It is shown that through the utilisation of the oxidative decarbonylation reagent trimethylamine-N-oxide, Me₃NO but-2-yne will successively displace carbonyl ligands to yield the complexes [Ru₆C(CO)₁₅(m³:h²:h¹:h¹-Me₂C₂)], 2, [Ru₆C(CO)₁₄(m₃:h²:h¹:h¹:-Me₂C₂)(m:h²:h²-Me₂C₂)], 3. [(Ru₆C(CO)₁₂(m₃h²:h¹:h¹-Me₂C₂)₃], 5 and [Ru₆C(CO)₁₀(Me₂C₂)₄], 6. It is observed that the octahedral array of atoms in complex 2 undergoes a polyhedral rearrangement when reacted to form 3 which exhibits a capped square based pyramid geometry, Complex 3 loses a carbon monoxide ligand to produce [Ru₆C(CO)₁₃(Me₂C₂)₂], 4 via chemical and thermal activation. Complexes 3, 5 and 6 display unusual electron counts of 88 when according to polyhedral electron counting predictions such geometries should have counts of 86, this is discussed. The Chapter goes onto investigate the synthesis of complexes which have difference alkyne ligands bound to the cluster fragment. Complexes [Ru₆C(CO)₁₄(Me₂C₂)(Ph₂C₂), 7, [Ru₆C(CO)₁₅(MeC₂Et)], 8, [Ru₆C(CO)₁₄(MeC₂Et)(Me₂C₂)], 9 and [Ru₆C(CO)₁₂(MeC₂Et)(Me₂C₂)(Ph₂C₂)], 11 are prepared and characterised. The Chapter closes with concluding remarks and an update of the current state of play of the research.

APA, Harvard, Vancouver, ISO, and other styles

38

Hill, Geoffrey Stephen. "Organoplatinum complexes as models for alkane activation." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/nq28489.pdf.

Full text

APA, Harvard, Vancouver, ISO, and other styles

39

Yahya, Rosiyah. "Alkane hydrogenolysis on supported Group VIII metals." Thesis, Brunel University, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.257670.

Full text

APA, Harvard, Vancouver, ISO, and other styles

40

Ash, Philip Andrew. "Surface freezing in surfactant/alkane/water systems." Thesis, Durham University, 2011. http://etheses.dur.ac.uk/843/.

Full text

Abstract:

Surface freezing transitions in mixed monolayers of a homologous series of cationic surfactants, the alkyltrimethyl ammonium bromides (CnTAB where n = 12, 14, 16, 18), as well as a range of non-ionic, zwitterionic and biological surfactants, have been investigated ellipsometrically with a range of n-alkanes (Cm where m = 12 – 20, 28). Two distinct solid phases are observed depending upon the chain length difference between surfactant and n-alkane. Type I solid phases consist of a surface frozen mixed monolayer and are formed when this difference is small. Type II solid phases are bilayer structures with a frozen layer of neat n-alkane above a liquid-like mixed monolayer. Type II freezing was thought to occur via wetting of surface frozen n-alkane, as previously reported type II transitions took place in the presence of surface frozen n-alkanes. Thermodynamically stable type II solid phases have now been found in the presence of n-alkanes that do not show surface freezing at the air/alkane interface, however, and so this picture is incomplete. In the presence of pentadecane, for example, the biological surfactant lyso-OPC forms a stable type II solid phase 6.5 °C above the n-alkane bulk melting point. Such a large surface freezing range is unprecedented for a type II system. Studies using external reflection FTIR (ER-FTIRS) and vibrational sum-frequency spectroscopies (VSFS) have been used to probe these novel behaviours. Results were fully consistent with the proposed structures of both type I and type II surface frozen layers. 2D correlation analysis of ER-FTIR spectra as a function of temperature showed that type II frozen layer formation does not proceed via a simple wetting transition, with the formation of a transient intermediate implied. Evidence for such an intermediate was provided by dynamic ellipsometry measurements on the type II C18TAB/n-eicosane system.

APA, Harvard, Vancouver, ISO, and other styles

41

Beal, Richard Kenneth. "Mechanisms of (bio)surfactant enhanced alkane biodegradation." Thesis, University of York, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.313856.

Full text

APA, Harvard, Vancouver, ISO, and other styles

42

Grootboom, Natasha Denise. "Alkane oxidation using metallophthalocyanine as homogeneous catalysts." Thesis, Rhodes University, 2002. http://hdl.handle.net/10962/d1007794.

Full text

Abstract:

Iron polychlorophthalocyanine (FePc(Cl)₁₆) and tetrasulfophthalocyanine ([M¹¹TSPc]⁴) complexes of iron, cobalt and manganese are employed as catalysts for the oxidation of cyclohexane using tert-butyl hydroperoxide (TBHP), chloroperoxybenzoic acid (CPBA) and hydrogen peroxide as oxidants. Catalysis using the FePc(Cl)₁₆ was performed in a dimethylformamide:dichloromethane (3 :7) solvent mixture. For the [Fe¹¹TSPc]⁴⁻, [Co¹¹TSPc]⁻ and [Mn¹¹TSPc]⁴⁻catalysts, a water:methanol (1:9) mixture was employed. The products of the catalysis are cyclohexanone, cyclohexanol and cyclohexanediol. The relative percentage yields, percentage selectivity and overall percentage conversion of the products depended on types of oxidant, or catalyst, concentrations of substrate or catalysts and temperature. TBHP was found to be the best oxidant since minimal destruction of the catalyst and higher selectivity in the products were observed when this oxidant was employed. Of the four catalysts investigated [Fe¹¹TSPc]⁴⁻ yielded the highest overall percentage conversion of 20%.The mechanism of the oxidation of cyclohexane in the presence of the FePc(Cl)₁₆ and [M¹¹TSPc]⁴⁻ involves the oxidation of these catalysts, forming an Fe(IlI) phthalocyanine species as an intermediate. Electrocatalysis using [Co¹¹TSPc]⁴⁻ as catalyst, employed an aqueous pH 7 buffer medium for electro-oxidation of 4-pentenoic acid. An enone is suggested as the only oxidation product of 4-pentenoic acid. No degradation of [Co¹¹TSPc]⁴⁻ was observed during the electrocatalytic process. In this process water was used as a source of oxygen therefore eliminating the production of by products from oxidant as in the case of TBHP and CPBA. This system was studied In an attempt to set up conditions for alkane electrocatalytic oxidation.

APA, Harvard, Vancouver, ISO, and other styles

43

Price, Claire Louise. "Candida CYP52 : alkane and fatty acid metabolism." Thesis, Swansea University, 2012. https://cronfa.swan.ac.uk/Record/cronfa42696.

Full text

Abstract:

Cytochromes P450 are a superfamily of haem-thiolate proteins found in all kingdoms of life. To date 11294 enzymes have been identified and have been shown to be involved in the metabolism of a wide variety of substrates, including hydrocarbons and xenobiotics. In yeast and fungi the hydroxylation of alkanes is associated with a family of cytochromes P450 enzymes known as CYP52s. These enzymes are involved in the terminal hydroxylation of long-chain alkanes resulting in the production of alcohols, which can be further converted to form fatty acids and diacids. In vivo such hydrocarbons can be subjected to beta-oxidation for use in growth. Alternatively, the products formed by CYP52 catalysed hydroxylation in vitro can be used in biotechnological applications. They can be used as platform chemicals in the production of a number of industrial products, including plastics, fragrances and antibiotics. The p-oxidation of fatty acids has been less well documented for Candida albicans than for other Candida species, therefore it was the aim of this study to investigate a) did cytochromes P450 exist in C. albicans that could possibly fulfil this function and b) to definitively assign function to a single cytochrome P450. Using a bioinformatic approach, five putative CYP52s were identified in C. albicans. Of these CYP52s, Alk1 was shown to have the greatest homology to the archetypal alkane-assimilating CYP52, CYP52A3 from C. maltosa. ALK1 heterologous gene expression in the brewer's yeast Saccharomyces cerevisiae allowed growth on hexadecane (C16:0) as the sole carbon source. This showed for the first time that Alk1 is involved in the hydroxylation of long-chain alkanes as normally S. cerevisiae is unable to utilise alkanes for growth. This study has also shown that Alk1 is able to interact with sterol substrates suggesting a possible role for CYP52s in sterol metabolism, which was previously unknown.

APA, Harvard, Vancouver, ISO, and other styles

44

Lin, Lin [Verfasser], Johannes A. [Akademischer Betreuer] Lercher, and Klaus [Akademischer Betreuer] Köhler. "Activation and Transformation of n-Alkanes and n-Alkene in Zeolites / Lin Lin. Gutachter: Johannes A. Lercher ; Klaus Köhler. Betreuer: Johannes A. Lercher." München : Universitätsbibliothek der TU München, 2012. http://d-nb.info/1031515380/34.

Full text

APA, Harvard, Vancouver, ISO, and other styles

45

Lin, Lin [Verfasser], Johannes [Akademischer Betreuer] Lercher, and Klaus [Akademischer Betreuer] Köhler. "Activation and Transformation of n-Alkanes and n-Alkene in Zeolites / Lin Lin. Gutachter: Johannes A. Lercher ; Klaus Köhler. Betreuer: Johannes A. Lercher." München : Universitätsbibliothek der TU München, 2012. http://d-nb.info/1031515380/34.

Full text

APA, Harvard, Vancouver, ISO, and other styles

46

Merkel, Roswitha. "Untersuchung zur Synthese und Eigenschaften von komplexen Oligospiroketalen." Phd thesis, Universität Potsdam, 2014. http://opus.kobv.de/ubp/volltexte/2015/7256/.

Full text

Abstract:

Es ist in dieser Arbeit gelungen, starre Oligospiroketal(OSK)-Stäbe als Grundbausteine für komplexe 2D- und 3D-Systeme zu verwenden. Dazu wurde ein difunktionalisierter starrer Stab synthetisiert, der mit seines Gleichen und anderen verzweigten Funktionalisierungseinheiten in Azid-Alkin-Klickreaktionen eingesetzt wurde. An zwei über Klickreaktion verknüpften OSK-Stäben konnten mittels theoretischer Berechnungen Aussagen über die neuartige Bimodalität der Konformation getroffen werden. Es wurde dafür der Begriff Gelenkstab eingeführt, da die Moleküle um ein Gelenk gedreht sowohl gestreckt als auch geknickt vorliegen können. Aufbauend auf diesen Erkenntnissen konnte gezeigt werden, dass nicht nur gezielt große Polymere aus bis zu vier OSK-Stäben synthetisiert werden können, sondern es auch möglich ist, durch gezielte Änderung von Reaktionsbedingungen der Klickreaktion auch Cyclen aus starren OSK-Stäben herzustellen. Die neu entwickelte Substanzklasse der Gelenkstäbe wurde im Hinblick auf die Steuerung des vorliegenden Gleichgewichts zwischen geknicktem und gestrecktem Gelenkstab hin untersucht. Dafür wurde der Gelenkstab mit Pyrenylresten in terminaler Position versehen. Es wurde durch Fluoreszenzmessungen festgestellt, dass das Gleichgewicht z. B. durch die Temperatur oder die Wahl des Lösungsmittels beeinflussbar ist. Für vielfache Anwendungen wurde eine vereinfachte Synthesestrategie gefunden, mit der eine beliebige Funktionalisierung in nur einem Syntheseschritt erreicht werden konnte. Es konnten photoaktive Gelenkstäbe synthetisiert werden, die gezielt zur intramolekularen Dimerisierung geführt werden konnten. Zusätzlich wurde durch Aminosäuren ein Verknüpfungselement am Ende der Gelenkstäbe gefunden, das eine stereoselektive Synthese von Mehrfachfunktionalisierungen zulässt. Die Synthese der komplexen Gelenkstäbe wurde als ein neuartiges Gebiet aufgezeigt und bietet ein breites Forschungspotential für weitere Anwendungen z. B. in der Biologie (als molekulare Schalter für Ionentransporte) und in der Materialchemie (als Ladungs- oder Energietransporteure).
In this dissertation the use of rigid Oligospiroketal (OSK)-rods as basic model for 2D- and 3D-systems was shown. For that purpose a bifunctionalized rigid rod was synthesized and was used in Azide-Alkine-clickreaction with itself and with other branched functionalized units. By theoretical calculations a statement about the novel bimodulation of the conformation of two OSK-rods which are linked by a clickreaction could be made. “Articulated rod” was introduced as new term, because the molecules could exist elongated or buckled. Based on this knowledge it became apparent that not only the size selective synthesis of polymers by using up to four OSK-rods is possible but also cycles with OSK-rods by using different click-reaction conditions can be synthesized. The newly developed group of “articulated rod” substances was examined regarding the equilibrium between buckled and elongated “articulated rod”. That for the articulated rod was functionalized with pyrenyl moieties in terminal position. By fluorescence measurements of these rods it could be shown that the equilibration is influenced by different temperatures and different solvents. For multiple applications a simplified strategy for synthesis with a wide range of functionalization in only one step of synthesis could be achieved. Photoactive articulated rods were synthesized, that could be selectively intramolecular dimerized. Additionally, amino acids were introduced as linker at the end of a articulated rod. By this a stereoselective synthesis of multiple functionaliations is possible. By the synthesis of complex articulated rods a novel field of research was found. There is a wide potential of research for more applications for example in biology (as molecular switch for transportation of ions) and in materials chemistry (as transporter for charge or energy).

APA, Harvard, Vancouver, ISO, and other styles

47

Montenegro, Rivelino V. D. "Kristallisation, Biomimetik und halbleitende Polymere in räumlich begrenzten Systemen." [S.l.] : [s.n.], 2003. http://deposit.ddb.de/cgi-bin/dokserv?idn=967796873.

Full text

APA, Harvard, Vancouver, ISO, and other styles

48

Allegrezza, Michael LeGrande. "Mechanistic Insight Into Photo-Polymerization Techniques Through Kinetic Analysis." Miami University / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=miami1605182244121264.

Full text

APA, Harvard, Vancouver, ISO, and other styles

49

García, Ruiz Víctor M. "Studien zur Anwendung der Olefinmetathese." [S.l.] : [s.n.], 2001. http://deposit.ddb.de/cgi-bin/dokserv?idn=962929832.

Full text

APA, Harvard, Vancouver, ISO, and other styles

50

Trenkle, James D. (James Douglas). "Phosphine-promoted cross-coupling reactions of propargylcopper reagents and alkenyl iodides and the total synthesis of (-)-gloeosporone via nickel-catalyzed epoxide-alkyne reductive macrocyclization." Thesis, Massachusetts Institute of Technology, 2007. http://hdl.handle.net/1721.1/39582.

Full text

Abstract:

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemistry, 2007.
Vita.
Includes bibliographical references.
I. Phosphine-Promoted Cross-Coupling Reactions of Propargylcopper Alkenyl Iodides Reagents and Alkenyl Iodides. An electron-rich phosphine additive is critical and sufficient for propargyl-selective couplings of propargylcopper reagents and alkenyl iodides. This method is complementary to those previously described, in which high allenyl selectivity is observed in analogous coupling reactions. While the basis of the phosphine effect requires further investigation, the information gained in these studies enables the synthesis of complex molecules by way of skipped enyne intermediates. ... II. Total Synthesis of (-)-Gloeosporone via Nickel-Catalyzed Epoxide-Alkyne Reductive Macrocyclization. The total synthesis of macrolide natural product (-)-gloeosporone 1 is described in 10 steps (LLS) and 5.2% overall yield. The key macrocyclization was performed via nickel-catalyzed reductive macrocyclization of an alkyne and a epoxide to give the 14-membered ring in 46% yield (4a ---> 3a; up to 67% yield could be achieved with stoichiometric nickel). This transformation differs from previous strategies in closing the macrocycle of 1 using more traditional approaches such as macrolactonization and ring-closing metathesis. ...
(cont.) Additional nickel-catalyzed macrocyclization studies of alkynes and epoxides were undertaken with other alkynylepoxides. With these studies we were able to recognize an important structural pattern (a 6,e-unsaturated ynoate) which might be necessary for efficient cyclization. Using this information, the nickel-catalyzed reductive cyclization of alkynes and epoxides was extended to the formation of 12- and 15-membered rings.
by James D. Trenkle.
Ph.D.

APA, Harvard, Vancouver, ISO, and other styles

We offer discounts on all premium plans for authors whose works are included in thematic literature selections. Contact us to get a unique promo code!