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Dissertations / Theses on the topic 'Organic synthesis ; Natural products ; Synthetic organic chemistry'

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Published: 4 June 2021

Last updated: 5 February 2022

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1

Wu, Boshen. "Synthesis of taurospongin A and other biologically active natural products." Thesis, University of Oxford, 2017. http://ora.ox.ac.uk/objects/uuid:37a34bc4-efb4-4a6b-9d44-a3ad1c8ae0be.

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This thesis firstly describes a synthesis of the natural product taurospongin A, a potent DNA polymerase beta inhibitor. Sharpless asymmetric dihydroxylation on olefin <b>E-1.60</b> followed by selective deoxygenation at C(2) via Barton‒McCombie reaction delivers the desired C(1)–C(10) carboxylic acid core. Subsequent esterification of the C(1)–C(10) fragment with C(1′)–C(25′) fatty acid furnishes the natural product in 13.5% yield. The structure of an unnamed natural product <b>2.14</b> isolated in 1974 is proven to be misassigned by previous studies within the Robertson group. As described i

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2

Nimkar, Sandeep Krishnaji. "Studies in asymmetric synthesis: Development of new synthetic methods for syntheses of natural products." Diss., The University of Arizona, 1993. http://hdl.handle.net/10150/186538.

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The research, to be discussed in three chapters, involves the development of new synthetic methods which are applicable to the total synthesis of many natural products. Chapter 1: As a part of a program to synthesize new auxiliary agents for asymmetric synthesis, we have prepared a structurally rigid acetal from norbornene in three chemical steps. This enantiomerically pure acetal has been used for resolution of racemic α-hydroxy esters and might be applied as a chiral auxiliary for diastereoselective reactions. Chapter 2: The Calicheamicin and Esperamicin antibiotics have shown remarkable bio

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3

Källström, Jan Eddy Adolf. "Synthesis studies towards daphlongeranine B." Thesis, University of Oxford, 2013. http://ora.ox.ac.uk/objects/uuid:638685a8-da64-488b-b65d-ba9a2111d4fb.

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This thesis describes the development of a synthetic route towards daphlongeranine B, an alkaloid isolated from the fruits of Daphniphyllum longeracemosum, by utilising an intramolecular Michael addition to form its unique tricyclic core. <strong>Chapter 1</strong> gives a general introduction to the family of Daphniphyllum alkaloids together with some recent examples, from the literature, illustrating some synthetic attempts towards structurally similar alkaloids. This chapter also features our retrosynthetic analysis of daphlongeranine B. <strong>Chapter 2</strong> details the synthesis of t

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4

Leslie, Pauline. "Studies towards the synthesis of chlorinated natural products." Thesis, University of Bristol, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.268989.

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5

Welch, Rosemary. "The development of new synthetic methods towards the synthesis of biologically active natural products." Thesis, University of Portsmouth, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.292089.

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6

Shah, Rushabh Surendra. "Total syntheses of the nakinadine alkaloids." Thesis, University of Oxford, 2013. http://ora.ox.ac.uk/objects/uuid:c022e538-9ff8-4914-8c17-dc0b3ed1fbae.

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This thesis is concerned with the development of methodology for the asymmetric syntheses of the nakinadine family of marine alkaloids and through these synthetic endeavours, seeks to confirm the structure and assign the relative and absolute configurations of these alkaloids for the first time.

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7

Dyson, Bryony Sara. "Determining the structures of halogenated marine natural products by total synthesis." Thesis, University of Oxford, 2011. http://ora.ox.ac.uk/objects/uuid:31737a99-a13c-4110-b36d-1c043b66565b.

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Elatenyne, a brominated C<sub>15</sub> acetogenin isolated from the red Laurencia elata marine algae, was originally assigned a pyranopyran structure. Previous total synthesis of the pyranopyran structure has found this assignment to be incorrect. During this work the revised 2,2’-bifuranyl skeleton of elatenyne was suggested, but this skeleton has 32 possible diastereomers. The most likely diastereomer of elatenyne was predicted using computational <sup>13</sup>C NMR chemical shift calculation in combination with the possible stereochemical outcomes from the proposed biosynthesis. Chapter 1 i

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8

O'Riordan, Timothy Jeremiah Cornelius. "Synthesis of the pyrrolidinone core of oxazolomycin A." Thesis, University of Oxford, 2009. http://ora.ox.ac.uk/objects/uuid:298746d3-69df-47b9-8a83-7949df1c94dc.

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This thesis describes the development of synthetic strategies towards the densely functionalised pyrrolidinone core of the polyene β-lactone-γ-lactam antibiotic oxazolomycin A. <strong>Chapter 1 The oxazolomycins</strong> The oxazolomycins, a unique class of biologically active molecules containing a spiro-fused β-lactone-γ-lactam ring system are introduced. The isolation, structural elucidation and biological properties of the oxazolomycins as well as those of the structurally related inthomycins are reviewed. <strong>Chapter 2 Previous syntheses</strong> The two total syntheses of

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9

Phillips, Andrew. "Studies towards the total synthesis of patellazole B." Thesis, University of Cambridge, 2017. https://www.repository.cam.ac.uk/handle/1810/269364.

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The patellazoles are a family of marine polyketide natural products first isolated from Lissoclinum patella in 1988 by both the Moore and Ireland groups. They exhibit significant cytotoxicity against the HCT 116 human colon tumour cells. To date however, their full 3D stereostructure have yet to be elucidated, which has hindered their development as potential drugs, and hampered full investigation into their biological mechanism of action and has deterred total synthesis efforts. This thesis describes synthetic efforts towards Patellazole B, which exhibits the highest potency of the three main

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10

Elbert, Bryony L. "The synthesis and applications of cyclic alkenylsiloxanes." Thesis, University of Oxford, 2014. http://ora.ox.ac.uk/objects/uuid:a332365e-22f2-4449-b517-3fd8a62ea8a3.

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This thesis describes the development of robust methodology to access cyclic alkenylsiloxanes, and their subsequent application in Hiyama-Denmark cross couplings. An early chapter shows the identification of Lindlar reduction conditions capable of generating cyclic alkenylsiloxanes from alkynylsiloxanes in high yields. The use of such species in Hiyama-Denmark cross coupling is then examined, with particular emphasis on the development of fluoride-free conditions, previously unreported for this class of organosilane. A ring-size dependent orthogonality is revealed, where 5-membered cyclic alke

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11

Saliba, Regis C. "Design and synthesis of nanoparticles functionalised with Lewis oligosaccharides for selective targeting of DC-SIGN." Thesis, University of Oxford, 2014. http://ora.ox.ac.uk/objects/uuid:21906fcb-b29f-415b-a1b7-bca375f06a2b.

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Dendritic cells (DC) are one of the major antigen presenting cells (APC) of the body. They, by capture of antigen and cross-presentation of these antigens, activate dormant T-cells and co-activate B-cells. As such they regulate the immune system toward either a more humoral type immune response or a more cellular type immune response. These properties have made them very studied over the past decade and many works have focus on the development of vaccine or therapeutic using DCs as a target. However, most of these actual studies have been done by injection of in vitro pre-activated DCs. The ma

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12

Heaviside, Elizabeth Anne. "Analogues of antibacterial natural products." Thesis, University of Oxford, 2012. http://ora.ox.ac.uk/objects/uuid:6b5bd771-515b-49d0-8ec9-cee115d3aebf.

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Analogues of Antibacterial Natural Products Elizabeth Anne Heaviside, St Catherine’s College, University of Oxford DPhil Thesis, Trinity Term 2012 This thesis is concerned with the synthesis and biological evaluation of structural mimics for the natural products 16-methyloxazolomycin and lemonomycin which display potent biological activity including antibacterial and antitumour activity. Chapter 1 explores methods and approaches to the discovery of new antibacterial drugs and the challenges faced in this respect. It also gives an overview of the properties of the natural products investigated

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13

Cordonnier, Marie-Caroline A. "Palladium-catalysed cascade cyclisation of alkynyl silanes and studies towards rubriflordilactone A." Thesis, University of Oxford, 2011. http://ora.ox.ac.uk/objects/uuid:24302e85-de80-4562-a98e-ee0e6ba93862.

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In this work, a new methodology for the synthesis of a number of silylated bicyclic dienes has been reported. These bicyclic dienes allowed access to a variety of enones and phenols in 2 further steps. The stabilities and reactivities of different dialkylisopropoxy silanes have been evaluated,revealing relative instability of the dimethylisopropoxy silyl group towards chromatography. When using the analogous diethylisopropoxy silyl group instead, the products showed greater stability towards chromatography, however a higher temperature was necessary to oxidise the more sterically hindered sily

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14

Hawkins, Alison. "Studies towards the total synthesis of manzamine A." Thesis, University of Oxford, 2013. http://ora.ox.ac.uk/objects/uuid:0ca64b5d-bc7c-4624-b9c2-4b5f7b6967e3.

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This thesis describes studies towards the total synthesis of manzamine A (9), a marine alkaloid. Two routes are presented. The first route applied a novel palladium-catalysed arylative allene spirocyclisation cascade to the synthesis of manzamine A (9). In the first generation, a short route was developed to access the tricyclic ACE core 263a in only nine steps. The second generation applied the palladium-catalysed cascade to a similar system which utilised non-terminal allene pro-nucleophile 450 in an attempt to access a homologated derivative of the ACE core. The second route relied on a dia

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15

Clark, J. Stephen. "Approaches to the synthesis of oxocane natural products." Thesis, University of Cambridge, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.293810.

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Newman, Nicola Ann. "Cyclisation strategies towards the synthesis of natural products." Thesis, University of Southampton, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.342637.

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17

Blunt, Christoper Edward. "The synthesis of benzisothiazole and benzothiazole natural products." Thesis, University of Nottingham, 2018. http://eprints.nottingham.ac.uk/49541/.

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Chapter 1 gives an introduction to benzisothiazole and benzothiazole natural products. It explores the scope of natural products that are known within these families and discusses what they are used for, how they have been made and how they may have been biosynthesised. Chapter 1 provides a review of each family of natural products in turn. Chapter 2 describes the total synthesis of the benzisothiazole natural products aulosirazole and pronqodine A, and a series of unnatural analogues. The Chapter begins with a short discussion on the use of the Diels-Alder reaction for the formation of naphth

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18

Nolan, William Peter. "Synthesis of indolo[2,3-A]carbazole natural products." Thesis, University of Cambridge, 1990. https://www.repository.cam.ac.uk/handle/1810/272982.

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19

Larsson, Michael. "Natural products from nonracemie building blocks : synthesis of pine sawfly pheromones." Doctoral thesis, KTH, Kemi, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-128.

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This thesis describes a number of synthetic approaches for obtaining chiral, enantiomerically pure natural products, in particular some semiochemicals. This has been accomplished by using various strategies; by starting from compounds from the chiral pool, by using chiral auxiliaries, via enzymatic resolutions or by chemical asymmetric synthesis. Hence, the sexual pheromone of Microdiprion pallipes, a propanoate ester of one or several isomers of 3,7,11-trimethyltridecan-2-ol, was synthesised, both as a mixture of all isomers and as the sixteen pure, individual stereoisomers. These compounds w

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20

Brooks, Steven Halton. "Studies in methodology toward the synthesis of natural products." Thesis, University of Reading, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.385612.

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21

Dexter, Hannah. "Towards the synthesis of heterocycle containing natural products." Thesis, University of Nottingham, 2017. http://eprints.nottingham.ac.uk/40735/.

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Chapter 1 gives an introduction to ribosomally synthesised and post-translationally modified peptides. The different classes of this group of natural products are described. Examples of linear azol(in)e-containing peptides and cyanobactins are given, along with more detail about these classes of peptides and examples of their chemical synthesis. Chapter 2 explains the importance of the natural product goadsporin 64, along with the retrosynthesis and a review of methods to synthese oxazoles, thiazoles and dehydroalanines. The first total synthesis of goadsporin 64 is then reported, demonstratin

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22

Kyle, Andrew F. "Total synthesis of (–)-nakadomarin A and an approach to the diazatricyclic core of the madangamines." Thesis, University of Oxford, 2012. http://ora.ox.ac.uk/objects/uuid:43e8044f-6860-47a2-9850-5f42990d4a68.

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This dissertation describes work towards two marine alkaloid natural products of the manzamine family. The total synthesis of (–)-nakadomarin A, via two conceptually different strategies is described along with the development of a novel nitro-Mannich-Mannich cascade reaction, which has been applied in a synthesis of the diazatricyclic core of the madangamines. A short and highly stereoselective synthesis of (–)-nakadomarin A has been developed. A sequential alkyne ring-closing metathesis/syn selective reduction strategy enabled the stereoselective construction of the Z-configured alkene in th

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23

Stefinovic, Marijan. "Novel synthetic and mechanistic metholologies for the construction of natural products." Thesis, University of Reading, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.385614.

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24

Docherty, Paul Henry. "Diastereocontrolled synthesis of hetero- and carbocycles via manganese(III) and copper(II) : towards a novel prostaglandin total synthesis." Thesis, University of Oxford, 2008. http://ora.ox.ac.uk/objects/uuid:6ca5556a-3d2d-454a-abbd-0a3a269c5724.

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The prostaglandins are a unique family of natural products found in all mammalian life, including humans. Their biological significance is profound, and they are responsible for a vast array of bodily functions. This importance, coupled with their low concentration in vivo, has made them attractive targets for total chemical synthesis. The work herein describes synthetic efforts towards their synthesis using an oxidative radical cyclisation to construct the key [3.3.0]-bridged bicyclic lactone, from which the prostaglandin skeleton may be derived. Key to this was the development of manganese(I

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Stevens, Kiri. "Methodology for the synthesis of NP25302 and other bioactive natural products." Thesis, University of Oxford, 2011. http://ora.ox.ac.uk/objects/uuid:ae18879e-d75e-4280-ba55-1ae08e64034f.

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Total synthesis of the pyrrolizidine alkaloid NP25302: (+)-NP25302 is an unusual vinylogous urea containing pyrrolizidine alkaloid shown to exhibit cell adhesion inhibition. It was envisaged that this natural product could be accessed by a novel 5-endo-dig cyclisation to construct the pyrrolizidine core, and a Curtius rearrangement to install the vinylogous urea motif. This methodology was first tested on a model system, furnishing nor-NP25302 from L-proline in 12 steps and 9% overall yield. The total synthesis of (±)-NP25302 was completed in 9 steps and 26% overall yield from ethyl 2-nitropro

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Logan, Angus W. J. "Synthesis of complex γ-lactones mediated by manganese(III)". Thesis, University of Oxford, 2012. http://ora.ox.ac.uk/objects/uuid:ab56e6c1-4069-462e-91ef-fbc83f525ee4.

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This thesis details the development of manganese(III) acetate-mediated oxidative radical cyclisation methodology. In particular, the use of radicals to form complex, highly sterically congested and strained carbo- and heterocycles in a stereocontrolled manner is described. Chapter 1 gives a summary of the literature regarding three key areas relevant to this work. Radical reaction mechanisms are introduced, including the use of transition metals and lanthanides in C-centred radical cyclisations. The formation of highly sterically congested vicinal all-carbon quaternary stereocentres is also di

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27

Fabiano, E. "Synthesis and reactions of amino compounds relating to natural products." Thesis, University of Newcastle Upon Tyne, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.373890.

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Robinson, Anthony R. "Approaches to the synthesis of oxocane and oxonane natural products." Thesis, University of Cambridge, 1994. https://www.repository.cam.ac.uk/handle/1810/273010.

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29

Marx, Leo. "Studies towards and total synthesis of pyrrolidinone containing natural products." Thesis, University of Oxford, 2014. http://ora.ox.ac.uk/objects/uuid:84ac3159-3c5e-4826-89d1-4b293935ed53.

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<strong>Chapters 1</strong> and <strong>2</strong> of this thesis focus on the application manganese(III) and copper(II)-mediated oxidative radical cyclisation of alkenyl amidomalonates to the formation of pyrrolidinone-lactones and their subsequent use in the total syntheses of highly bioactive natural products. A novel concise total synthesis of (-)-salinosporamide A based on the oxidative cyclisation previously developed in the group is presented in <strong>chapter 1</strong>. The second chapter discusses the work towards the pyrrolidinone core of the oxazolomycin. Each chapter contains its

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Hariprakasha, H. K. "Synthesis Of Natural Products Based On Cyclohexadienes." Thesis, Indian Institute of Science, 1996. http://hdl.handle.net/2005/118.

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The thesis entitled "Synthesis of Natural Products Based on Cyclohexadienes" consists of two chapters. Chapter 1 is divided into two parts. Part I gives a brief introduction to the structure, synthesis, biosynthesis and biological activities of some naturally occurring phthalides (eg. mycophenolic acid 1, zinniol2, phthalides 3 & 4). A general strategy for the preparation of highly substituted phthalides is also described. Cycloaddition of 1,s-dimethoxycoclohexa-1, 4-diene with dimethylacetylenedicarboxylate(DMAD) followed by an Alder-Rickert reaction gave the diester 5 which upon hydrolysis w

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Lipinski, Radoslaw Michal. "Synthesis of the ABC fragment of pectenotoxin-4." Thesis, University of Oxford, 2012. http://ora.ox.ac.uk/objects/uuid:123bf4c1-844a-492a-abdb-f7555719d7ff.

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This thesis details the application of two synthetic methodologies, developed by the Donohoe group, to the synthesis of the ABC fragment of pectenotoxin-4, a macrolide marine natural product that consists of 19 stereogenic centres, three tetrahydrofuran rings, one spiroketal and one bicyclic ketal embedded within a 26-membered macrocycle. Pivotal to the developed synthetic route was the utilisation of an unprecedented cascade osmium catalysed oxidative cyclisation for the construction of two THF rings (the BC ring system). After successfully developing a model system for the synthesis of the A

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Ayers, Benjamin James. "The synthesis and biology of iminosugars and their precursors." Thesis, University of Oxford, 2014. http://ora.ox.ac.uk/objects/uuid:2441a224-0e6f-42e9-97d2-63dd3f6c49c3.

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Iminosugars are carbohydrate mimics, where the endocyclic ring oxygen has been replaced by nitrogen. This substitution affords these compounds their inhibitory activity towards sugar-processing enzymes (glycosidases) and, as a consequence, their chemotherapeutic potential in the treatment of a broad range of diseases. Several iminosugars are currently in clinical trials or have entered the market as approved drugs. This has consequently led to increasing levels of research into their synthesis and application, both in terms of the development of efficient methodology to access naturally occurr

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Figuccia, Aude L. A. "Total asymmetric syntheses of iminosugars." Thesis, University of Oxford, 2015. http://ora.ox.ac.uk/objects/uuid:7075b45f-e3e1-4ae6-a544-4d6e54d4714e.

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This thesis is concerned with the development of ring-closing iodoamination and ringexpansion methodology and its subsequent application to the asymmetric syntheses of pyrrolidine and piperidine iminosugars. <strong>Chapter 1</strong> highlights the remarkable biological properties displayed by iminosugars and introduces methods for the formation of the pyrrolidine and piperidine sub-classes. <strong>Chapter 2</strong> describes investigations into the ring-closing iodoamination of bishomoallylic amines which occurs with concomitant <i>N</i>-debenzylation to give an iodomethyl pyrrolidine scaf

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Allwein, Shawn Paul. "Iterative strategies toward the synthesis of fused ether ring systems and the synthesis of fused ether containing natural products." Diss., The University of Arizona, 2001. http://hdl.handle.net/10150/280230.

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A highly efficient and general approach to fused ether ring systems has been presented. The approach couples stereoselective C-glycoside forming reactions with subsequent annulations. C-glycosides were formed from glycals through an oxidation and carbon-carbon bond forming sequence. Annulations involving a two step methylenation/enol ether-olefin ring closing metathesis or a single flask, acid mediated cyclization/elimination proved to be efficient tribenzyl- D-glucal (95), [4.4.0] and [4.5.0] bicyclic enol ethers (194, 200, 204) were stereoselectively generated in 2-4 steps in good overall yi

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Gatland, Alice Elizabeth. "Palladium-catalysed enolate arylation in the synthesis of isoquinolines." Thesis, University of Oxford, 2014. http://ora.ox.ac.uk/objects/uuid:f106760d-2375-4d56-81b2-faa6ee96cabc.

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<strong>Chapter 1. Introduction</strong> Scientific background on the development of homogeneous palladium-catalysed cross coupling reactions, focusing on the α-arylation reaction of enolates and its application to the synthesis of heteroaromatic compounds. The classical syntheses of isoquinolines are discussed, followed by an account of modern methods for their synthesis, including the recent α-arylation-based methodology developed by the Donohoe group. <strong>Chapter 2. Results and Discussion</strong> 2.1 Studies towards the development of a palladium-catalysed, C–H activation-b

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Rathi, Akshat Hemant. "Studies towards the synthesis of complex amino acids derived from microsclerodermins." Thesis, University of Oxford, 2012. http://ora.ox.ac.uk/objects/uuid:ca121a22-aee7-4da5-bd0d-dc7ee6e53bea.

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This thesis describes the studies towards the synthesis of β-amino acids found in the microsclerodermins, a family of complex macrocyclic hexapeptides. These β-amino acids have four or five contiguous stereocentres and an aliphatic side-chain. The synthetic route utilised an aminohydroxylation reaction to install the most challenging moiety in the structure - the 1,2- amino alcohol. The work aimed to construct the core structure (five contiguous stereocentres) of the β-amino acids and install the side-chain later to enable the synthesis of multiple members (A, B, F, G, H and I) of the microscl

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Tan, Song Wei Benjamin. "Natural product inspired organic synthesis : enantiopure heterocycles modelled on pramanicin." Thesis, University of Oxford, 2014. http://ora.ox.ac.uk/objects/uuid:2368dca6-7fe5-46b7-a913-6fecbaa21bf0.

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This thesis is concerned with the synthesis of chiral pyrrolidinone scaffolds as mimics of the natural product pramanicin, and the evaluation of their antibacterial properties for use towards the development of potential novel antibacterial lead compounds. Chapter 1 discusses the urgency of the antibiotic resistance problem as well as the current lack of new antibiotics in the drug pipeline. This dearth of new antibacterials is partly attributed to the combinatorial libraries used in the screening process which occupies a limited chemical space. By applying the natural product-inspired paradig

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Ferrara, Steven. "Oxidative radical cyclisations for total synthesis." Thesis, University of Oxford, 2013. http://ora.ox.ac.uk/objects/uuid:f91dbfcd-4e9a-41f6-8e16-b86855930c3f.

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Manganese(III) acetate mediated radical cyclisations provide a mild and powerful tool in the construction of complex bicyclic systems. This thesis focuses on the formation of a number of alkenyl substituted [3.3.0]-bicyclic γ-lactones utilising a manganese(III) acetate/copper(II) triflate induced radical cyclisation. The methodology was then applied to a short catalytic and enantioselective synthesis of (+)-aphanamol I and related natural products. Chapter 1 presents a summary of the theories and methodology which will be utilised in this work. In particular, a key focus will revolve around ox

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Powell, Kimberley Jade. "Synthetic and biophysical studies on the tridachiahydropyrone family of natural products." Thesis, University of Nottingham, 2014. http://eprints.nottingham.ac.uk/14228/.

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This thesis primarily details synthetic and biophysical studies on the tridachiahydropyrone family of natural products. The general aim of this work was to explore an hypothesis regarding the location and function of these metabolites, isolated from sacoglossan molluscs. Specifically, it was hypothesised that tridachiahydropyrone is synthesised photochemically from linear polyene precursors via a selective double bond isomerisation-6pi electrocyclisation sequence which occurs within the cell membrane of the producing organism. Furthermore, it was postulated that this reaction sequence, and sub

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Aldred, Gregory. "Studies towards the total synthesis and structural elucidation of leiodolide A." Thesis, University of St Andrews, 2015. http://hdl.handle.net/10023/6657.

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In 2006, the secondary metabolite leiodolide A was isolated from a newly discovered deep-sea sponge of the genus Leiodermatium. The 19-membered macrolide represented a new class of mixed polyketide, nonribosomal, peptide synthetase natural products. A total synthesis of leiodolide A is yet to be achieved and is of specific interest, not only for its complex structure and undefined stereochemistry, but also the potent cytotoxic properties it possesses, particularly towards leukaemia, non-small cell lung and ovarian cancers. A synthetic strategy for leiodolide A must be flexible to overcome the

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Wallace, Stephen. "A cascade approach towards the gephyrotoxins." Thesis, University of Oxford, 2012. http://ora.ox.ac.uk/objects/uuid:1f7b55ec-0346-498c-be03-81f3b9fde2f5.

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The aim of this project was to develop a cascade approach towards perhydropyrrolo-[1,2-a]-quinolines and to apply this to the asymmetric synthesis of the gephyrotoxin alkoids. Chapters Two and Three outline the development of a synthetic route towards a range of cascade precursors, whilst Chapter Four outlines investigations into the enamine-Michael cascade. Central to understanding the cascade process was the discovery that the major product of the enamine-Michael cascade was the unusual tricyclic hydroquinium salt. This can subsequently be engaged in a diastereoselective inter- or intramolec

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Rali, T. "Approaches to the synthesis of 5- and 6-membered nitrogen containing heterocyclic natural products." Thesis, University of East Anglia, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.370395.

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Tatton, Matthew R. "New methods for the synthesis of aromatic compounds." Thesis, University of Oxford, 2014. http://ora.ox.ac.uk/objects/uuid:52a95189-d8ea-432f-aefd-4f9ae7ef996a.

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<strong>Introduction</strong> The introduction describes the importance of arylamine compounds to society and provides a brief overview of the methods available for their synthesis. The application of metathesis catalysis to the de novo synthesis of heteroaromatic compounds is also described. <strong>Results and discussion</strong> The first section describes efforts towards the de novo synthesis of arylamines using a cross metathesis/oxidation protocol to form a 1,5-unsaturated dicarbonyl followed by an amine mediated cyclisation. The scope with respect to the 1,5-unsaturated dicarbonyl and a

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Snell, Robert Henry. "Development and application of asymmetric C-N bond formation." Thesis, University of Oxford, 2011. http://ora.ox.ac.uk/objects/uuid:512e617a-2b01-45f3-86ae-c0cf4b874149.

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A synthetic investigation on the chemistry of cyclotryptamine derived natural products, with a particular focus on the synthesis of the trimeric-alkaloid, hodgkinsine. Methodology has been developed to tackle this complex natural product which utilises a desymmetrization approach; this strategy hinges on the development and applications of asymmetric C-N bond forming reactions. Chapter one examines elements of symmetry in natural products, looking in particular at the synthesis of compounds which contain cyclotryptamine functionality. Chapter two contains a brief review of enantioselective des

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Fox, Ryan Michael. "Total Synthesis of The Bidensyneosides; Remarkable Protecting Group Effects in Glycosylation And Synthetic Efforts Towards The Total Synthesis of A Pentaacetylenic Glucoside." Miami University / OhioLINK, 2004. http://rave.ohiolink.edu/etdc/view?acc_num=miami1091480459.

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Hirner, Sebastian. "New Methodologies in Organic Chemistry: Applications to the Synthesis of α-Amino Acids and Natural Products". Doctoral thesis, KTH, Organisk kemi, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-11112.

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This thesis deals with the development and application of new synthetic methodology in organic chemistry. The first part describes the development of a new protocol for the synthesis of 3-pyrrolines by means of a microwave-assisted ring-expansion reaction of 2-vinylaziridines. In addition, this methodology is implemented as a key-step in a formal total synthesis of the antibiotic (-)-anisomycin. In the second part, a new methodology for the synthesis of arylglycines from Weinreb amides is described. In this procedure, a Grignard reagent is added to the iminium ion formed from the Weinreb amide

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Liau, Brian Bor-Jen. "Total Syntheses of Fastigiatine and the Hibarimicin Aglycons." Thesis, Harvard University, 2013. http://dissertations.umi.com/gsas.harvard:10831.

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Part one of this two-part thesis describes my efforts toward the total syntheses of the complex polycyclic alkaloids himeradine A and fastigiatine, which are members of the Lycopodium family of natural products. A cascade reaction sequence featuring a biosynthesis-inspired transannular Mannich reaction was planned to construct the strained and densely functionalized pentacyclic cores of the molecules from acyclic starting materials. After difficulties were encountered in a first-generation synthesis plan toward himeradine A, a second-generation synthesis plan was eventually successful in accom

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Kenton, Nathaniel T. "Total Synthesis of Azaspiracid-3, C20-epi-Azaspiracid-3, and Structural Definition of the Azaspiracids." The Ohio State University, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=osu1523545452232749.

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Lorkin, Thomas James Anthony. "Asymmetric synthesis of the Martinella alkaloids." Thesis, University of Oxford, 2013. http://ora.ox.ac.uk/objects/uuid:e8bcf4df-c046-4daf-9f87-12190e3992c3.

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This thesis is concerned with the application of the conjugate addition of enantiopure lithium amides in the asymmetric syntheses of (−)-martinellic acid. Chapter 1 introduces the importance of the quinoline motif in a wide variety of natural products and pharmaceuticals. The natural products (–)-martinellic acid and (+)-martinelline are introduced and previous methods for their synthesis are described. Chapter 2 introduces the conjugate addition reaction of lithium N-benzyl-N-α-methylbenzylamide as a means of synthesising β-amino esters from α,β-unsaturated esters. Both “tandem” and “stepwise

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Turkut, Engin. "Chemoenzymatic Synthesis Of Biologically Active Natural Products." Master's thesis, METU, 2004. http://etd.lib.metu.edu.tr/upload/12604854/index.pdf.

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Racemic metyhl 3-cyclohexene-1-carboxylate was resolved via enzymatic hydrolysis to afford the enantiomerically enriched 3-cyclohexene-1-carboxylic acid with PLE (S-configuration), HLE (S-configuration), CCL (S-configuration) and PPL (R-configuration) . The nucleoside&amp<br>#65533<br>s precursor, 5-(hydroxymethyl)-2-cyclohexen-1-ol (19), was synthesized by iodolactonization, followed by iodine elimination and the reduction of the lactone. In connection with this work, alpha,beta-unsaturated and saturated cyclic ketones were selectively oxidized on alpha&#039<br>- and alpha-positions using Mn

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