The investigation has been focussed largely on the chemistry and stereo-directing potential of camphor-derived compounds. The major regioisomer produced on partial hydrolysis of N-benzylcamphorimide was identified, by one- and two-dimensional NMR and X-ray crystallography, as (+)-(1S,3R)-(N-enzylcarbamoyl)-2,3,3-trimethylcyclopentanecarboxylic acid, the methyl ester of which was shown to undergo an unexpected intramolecular rearrangement during LAH reduction to afford (1S,3R)-Nbenzyl-3-hydroxymethyl-2,2,3-trimethylcyclopentane carboxamide. Several tartrate- and camphor-derived diols have been investigated as chiral auxiliaries in various asymmetric reactions of corresponding acetals of α,β-unsaturated aldehydes. MCPBA epoxidation of the tartrate-derived acetals afforded epoxy acetals in 4-12% diastereomeric excess. The camphor-derived acetals were obtained solely as the exosubstituted diastereomers, the stereochemistry being confirmed by two-dimensional NMR spectroscopy and X-ray crystallography. Simmons-Smith cyclopropanation of these camphor-derived acetals afforded cyclopropyl products with diastereoselectivities of 4% d.e. for the bornane-2,10-diol acetal and 46->99% d.e. for the bomane-2,3-diol acetals. In order to increase diastereofacial selectivity, a camphor-derived diol having a bulky substituent at C-10 was prepared, viz., phenyl 2,3-dihydroxybomane-10sulfonate, and α,β-unsaturated acetals of this diol were shown to undergo Simmons-Smith cyclopropanation with complete topological control (>99% d.e.), the diastereoselectivities being conveniently determined by ¹H and ¹³C NMR spectroscopy. Computer modelling, with the software package HYPERCHEM®, was used to explore the stereochemical aspects of the Simmons-Smith cyclopropanation, and hydrolysis of one of the cyclopropyl acetals has permitted the diastereoselective bias to be confirmed. (+)-Pinane-2,3-diol was also investigated as a chiral auxiliary in the Simmons-Smith reactions of α,β-unsaturated aldehydes, and moderate diastereoselectivities (20-30% d.e.) were observed. In a series of exploratory studies, the Diels-Alder reaction of the 2,3-dihydroxybomane-10-sulfonate acetal of trans-cinnamaldehyde with cyclopentadiene afforded a single cycloadduct, while OSO₄ dihydroxylation, MCPBA oxidation and alkylation of chiral acetals produced from both bomane-2,3-diol and phenyl 2,3-dihydroxybomane-10-sulfonate were less selective.

Oxidation of a ferrocenyl group in conjugation to another metal centre can alter the electron density at that metal centre and lead to a change in overall reactivity of a complex. Herein, the synthesis and characterization of redox active symmetrical and unsymmetrical ferrocenylalkene derivatives is described. A change in the standard redox potential of ferrocene (465 mV), to more positive potentials in vinylferrocene 1 (478 mV) and 4-phenylvinylferrocene 3 (499 mV), showed how manipulation of a redox potential can be effected on the ferrocenyl moiety by just using conjugation effects. A shift by +13 mV is observed in 1 and this potential more than doubled in 3 (+34 mV). Ferrocenylderived ruthenium alkylidene complexes were also prepared in a cross metathesis of 1 and 3 with Grubbs’ 1 (676.5 mV) to give complexes Ferrocenylidenebis( tricyclohexylphosphine)dichlororuthenium 14, 4-ferrocenylphenylidene-bis (tricyclohexylphosphine)dichlororuthenium 15 respectively. The extent of the electronic communication between the ferrocenyl group and the ruthenium centre was then estimated by looking at the positive or negative redox potential shifts of 14 and 15 as a result of 1 and 3. A large positive potential shift by 180 mV in 14 indicated that there was a strong electronic communication between the two metal centres, while the smaller, yet significant positive potential shift by 89.5 mV in 15 showed 3 to have a lesser effect on the ruthenium centre. Compounds 14 and 15 were tested in a Ring Closing Metathesis (RCM) of diethyldiallylmalonate showed enhanced reactivity.

Stereoselective hydroaminations of unactivated alkenes are rare as this represents a very challenging synthetic transformation. The most efficient examples occur in biased intramolecular systems and highly enantioselective intermolecular examples are rare, which is consistent with the forcing conditions required to catalyze the reactions. This limited reactivity also accounts for the lack of highly diastereoselective hydroamination variants. Recently our group has shown that intermolecular Cope-Type hydroamination of unactivated alkenes can be achieved using simple aldehydes as catalysts. The aldehyde promotes pre-association of the two reaction partners, inducing temporary intramolecularity resulting in a remarkably facile hydroamination event. This thesis will present the development of two reactions: intermolecular enantioselective Cope-type hydroamination and intermolecular diastereoselective Cope-type hydroamination of allylic amines.

Since only one example of an asymmetric synthesis which involved an intermediate containing an optically active ligand has been reported, two questions immediately arise: "Is this type of asymmetric synthesis an isolated example, or is it a stepping stone toward a generalized trend for Co (III) which may be extended to include levo rotatory, as well as dextro rotatory molecules?" In addition, asymmetric synthesis affords a new avenue for synthesizing resolved neutral complexes.

ASYMMETRIC DIMETHYLARGININE - COMPARSION OF CHROMATOGRAPHY AND IMMUNOMETRIC METHODS Objective:Asymmetric dimethylarginine (ADMA) is often discussed in connection with hyperhomocysteinemia and its toxic effect on vessel wall. ADMA concentration is usually measured by HPLC (High Performance Liquid Chromatography) after previous derivatisation. Recently, ELISA (Enzym Linked Immuno Assay) methods for ADMA determination were introduced and ELISA kits are commercially available. Method and Result:The aim of the study was to compare HPLC and ELISA methods for ADMA determination. For HPLC determination we used equipments from Thermo separation product (Florida, USA). After solid-phase extraction on polymer cation-exchange column and the following derivatisation with o-phthaldialdehyde the samples were separated using C18 column (mobile phase 8.7% acetonitril, 50 mmol/l phosphate buffer, pH 6.5) and a fluorescence detector. NG-monomethyl-L-arginine was used as an internal standard. ADMA® ELISA kit, based on a competitive principle, was obtained from DLD Diagnostika, Hamburg, Germany. ADMA was measured in EDTA plasma of 40 healthy blood donors and 40 hemodialysis patients with hyperhomocysteinemia. Conclusion: In spite of different principles both methods showed a very good correlation (r = 0.944, p<0.0001). ELISA...

No description available.

No / ¿-Ketophosphonates are prepared by a [3,3]-sigmatropic shift of enolphosphonates.

Doctor of Philosophy (PhD), Science / A concise stereo-selective synthesis of a protected form of APTO 1, an unusual amino acid component of microsclerodermin C 2, was undertaken. Sequential Sharpless Asymmetric Aminohydroxylation (AA) and Asymmetric Dihydroxylation (AD) reactions were used to introduce the chiral amino and hydroxyl groups. Specific directing groups were chosen to ensure high regio- and enantio-selectivity in these reactions. The target compound was reached in a linear reaction sequence of fourteen steps. The strategy was designed to generate common intermediates which could be used to access analogous amino acid fragments in other microsclerodermins. A protected form of AETD 3, from microsclerodermin E, was synthesised via a late-stage common intermediate. Initial studies into the modification of the sequence to allow access to AMPTD 4 and 10-methyl AMPTD 5 were made.

Doctor of Philosophy (PhD), Science / A concise stereo-selective synthesis of a protected form of APTO 1, an unusual amino acid component of microsclerodermin C 2, was undertaken. Sequential Sharpless Asymmetric Aminohydroxylation (AA) and Asymmetric Dihydroxylation (AD) reactions were used to introduce the chiral amino and hydroxyl groups. Specific directing groups were chosen to ensure high regio- and enantio-selectivity in these reactions. The target compound was reached in a linear reaction sequence of fourteen steps. The strategy was designed to generate common intermediates which could be used to access analogous amino acid fragments in other microsclerodermins. A protected form of AETD 3, from microsclerodermin E, was synthesised via a late-stage common intermediate. Initial studies into the modification of the sequence to allow access to AMPTD 4 and 10-methyl AMPTD 5 were made.

The hydroformylation of unfunctionalised olefins (such as prop-1-ene and oct-1-ene) is an extremely valuable process and is practised on a massive scale industrially in the synthesis of commodity chemicals. In fact, it represents the worlds largest scale application of homogeneous catalysis. As a result, the majority of research carried out on this reaction has been in the study of catalytic systems which provide high rates and selectivity for the production of linear aldehydes from terminal unfunctionalised olefins, with the products finding use in the production of plasticizers and detergents. Asymmetric hydroformylation, the enantioselective variant of this reaction is extremely attractive, as low cost or easily accessible olefins are transformed into highly versatile value-added enantioenriched aldehydes in a single step. However synthetic organic chemists interested in the synthesis of fine chemicals, both in academia and industry, have been slow to adopt this attractive protocol for the production of chiral aldehydes. This is mainly due to the fact that in the past catalysts for this reaction exhibited low activity and/or selectivity in this process. However, the last two decades have seen major advances, mainly in the development of highly effective chiral ligands, and with these developments the time has come to tackle the vastly under-explored area of asymmetric hydroformylation of more functionalised olefins. To set the scene for the research carried out during this project a brief introduction will be given which highlights the historical development of highly efficient catalysts for the hydroformylation of olefins. This will be accompanied by some examples of the use of this methodology in the synthesis of pharmaceutically relevant compounds. It should become apparent from the introduction that the asymmetric hydroformylation of functionalised olefins and in particular nitrogen containing olefins, has received very little attention despite the fact that over half of all medicinal compounds contain at least one nitrogen containing functional group. Firstly we describe hydroformylation as a useful alternative to the classical synthesis of a delicate chiral building block, namely α-formyl amides. These compounds, traditionally only available through multi-step synthetic procedures from enantiopure starting materials, have been accessed by asymmetric hydroformylation of readily accessible and in some cases commercially available acrylamides. By judicious choice of reaction conditions and selection of the appropriately active chiral ligand enantioenriched α-formyl amides (e.e. up to 82%) were produced in high yield. A comparison is made between the classical route and the hydroformylation route to illustrate the potential of this efficient transformation. We have studied the hydroformylation of enamides, a much under-studied substrate class in hydroformylation and developed knowledge of how some more functionalised 1,1- and 1-2-subtituted olefinic amides react under hydroformylation conditions. This research illustrates the work still to be done in terms of development of more active and selective catalysts for this reaction but despite limitations we developed a potential route to gamma amino aldehyde derivatives which could be used in turn in the synthesis of physiologically important gamma amino butyric acid (GABA) derivatives. We provide an example of the highly efficient and selective asymmetric hydroformylation of a bicyclic olefinic lactam, which is of industrial importance in the synthesis of carbocyclic nucleosides. We demonstrate the efficiency of this synthetic methodology by synthesising the central pharmacophore of a potent anti- HSV-1 (herpes simplex virus) carbocyclic nucleoside via a hydroformylationreduction protocol. The classical synthesis of this pharmacophore involves nine synthetic transformations to produce racemic material, whereas the hydroformylationreduction protocol produces highly enantioenriched material in just two steps. We also demonstrate some downstream chemistry of the aldehyde products showcasing the synthetic versatility of the aldehyde functionality in the production of a variety of functionalised cyclopentanes. Finally the synthesis and catalytic testing of a group of novel phosphine-phosphite ligands for use in asymmetric hydroformylation is described, one of which produces unprecedented regioselectivity and state of the art enantioselectivity in the asymmetric hydroformylation of styrene. Highly selective asymmetric hydroformylation of the other two ‘model substrates' in this reaction namely, vinyl acetate and allyl cyanide is also achieved. Having shown high activity and selectivity over these ‘model substrates' this ligand takes its place among the small group of highly active and selective ligands available for asymmetric hydroformylation and may also help to broaden the substrate scope of this efficient and atom-economic transformation.