This treatise is based on first-principles of the nano-scale properties of methanol synthesis on copper. We implement calculations using density functional theory within the framework of general gradient approximation. Initially, we gain insights into the mechanism of hydrogen dissociative adsorption on Cu(100) and find that the process is activated and the transition state involves an extended H... H bond. Hydrogens adsorb preferentially at surface hollows and upon saturation of these, penetrate lattice bulk and occupy interstitials. We proceed by monitoring the adsorption of atomic hydrogen on Cu(110) and find that the surface is likely to undergo reconstruction to (1x2) missing row Cu(110). We do not find threshold coverage for restructuring and suggest that the process initiates from zero-limit coverage. Bulk absorption is again found possible upon surface saturation. Moreover, we find that hydrogen dissolution on the reconstructed surface induces a contraction of the lattice, contrarily to the other surfaces examined. Based on this observation we add to the interpretation of experimentally observed hydrogen locking-in upon surface restructuring. Subsequently, we analyse the mechanism of carbon dioxide hydrogenation to formate. Three different possible routes are considered and the possibility of surface reconstruction taken into account. Reaction barriers are lower on the perfect structure, however results on the reconstructed surface agree better to experimental range. In all cases, transition states involve tilted formates. We also analyse the minimum energy pathway dependence on structural variables. We contribute to the understanding of the nature of interaction of several additional probable intermediates of methanol synthesis; namely dioxymethylene, formyl, formaldehyde and methoxy. The strongest bound species is dioxymethylene, closely followed by formate. We conclude that the active site of Cu(110) perfect and reconstructed surfaces are the top copper ridges in all cases examined. We explain the stabilisation of the adsorbents in terms of charge transfer from the top copper atoms to the bonding atoms of the species. Finally, we examine two different possible pathways to methanol synthesis from carbon dioxide and hydrogen. We consider seven different step reactions on each route. We infer that the most probable path involves dioxymethylene and that formyl is not likely to be a precursor to methanol. Based on our calculation of activation energies, we propose that the ratelimiting step is the hydrogenation of formate to dioxymethylene.

The aim of the research project described here was to develop a novel colourimetric nucleic acids biosensor based on polydiacetylene liposomes containing lipophilic peptide nucleic acids. Preliminary investigations in this area have shown that PNA-containing PDA liposomes can be constructed and that they are blue in colour as expected. However, their poor water solubility and the resulting precipitation made it necessary to synthesise and evaluate a second generation. In these, the PNA head-group is separated from the lipid tail by an amino diethylene glycol-type spacer molecule. The first hydrophilic spacer synthesised was 8-(tert-butoxycarbonyl)amino-3,6- dioxaoctanoic acid. Three methods based on the O-alkylation of mono-Boc, di-Boc and dibenzyl 5-amino-3-oxapentanol were devised. The Boc strategy afforded the corresponding ether in low yield of 20% while in the case of the dibenzyl approach a suitable methodology to effectively cleave the protecting groups from the amino function could not be found. Moreover, the model reaction between dibenzyl 8-amino-3,6- dioxaoctanoic acid and thyminyl PNA monomer afforded the corresponding conjugates in only 6%. An alternative type of connection to link the spacer to the PNA headgroup was thus sought. A 1,4-disubstituted [1,2,3]-triazole moiety was obtained in 60% yield by reacting spacer, 8-(tert-butoxycarbonyl)amino-3,6-dioxaoctan-1-azide and N-alkynyl PNA monomers bearing thymine, Cbz protected adenine and Cbz protected cytosine according to the conditions of the ‘Click’ reaction. These ‘spacer-PNA monomer’ intermediates were then functionalised at their N-terminus using 10,12-pentacosadiynoyl fluoride, to afford ‘lipid-spacer-PNA monomer’ models. The saturated conjugates were obtained by first preparing the ‘lipid-spacer’ intermediate, N-(8-azido-3,6- dioxaoctanyl)stearamide which was then connected to the N-alkynyl PNA monomers using the ‘Click’ reaction. Following this last strategy, a homothymine PNA dimer, prepared in solution phase, was also functionalised with the saturated lipid chain. This second generation of lipid functionalised-PNA monomer models were incorporated into PDA-liposomes. Upon photo-polymerisation, the liposome solutions became blue. They were found to be stable in solution, at 4 oC over long period of time. Their colour changed to red upon environmental changes (i.e. pH and temperature).

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This thesis reports the development of a novel asymmetric route towards a variety of NBoc protected allylic amines. This was achieved by creating an organocatalytic asymmetric transformation of aldehydes into a diverse range of allylic sulfides, and then applying a [2,3]-sigmatropic rearrangement with chirality transfer to afford five target motifs that will be discussed in individual chapters. Chapter One. introduces the general topi:along with supporting references. Chapter Two focuses on allylic amines and a [2,3]-sigmatropic rearrangement as a method ofasymmetric C-N bond construction via sulfimidation. The use of an oxaziridine reagent as an electrophilic source ofNBoc to induce rearrangement of prochiral allylic sulfides is then discussed prior to optimisation of a chemoselective version utilising chiral substrates..The chirality transfer is addressed in light of contradictory evidence, and confirmed as complete with simple aliphatic allylic sulfides and several unexplored substrates. Chapter Three highlights vinyl glycines and the development of an organocatalytic preparation of chiral substrates which had previously only been available from a limited chiral pool. Both (E) and (2) allylic sulfides were selectively prepared and the creation of a one-pot amination-rearrangement/N-S- bond cleavage sequence afforded both optical isomers of the target compounds with a variety of y-substituents. Chapter Four focuses on quaternary substituted vinyl glycines which were prepared with an array of a- and y-substituents by optimising the asymmetric organocatalytic preparation of geometrically enriched tri-substituted allylic sulfides through variation ofthe aldehyde and olefinating reagent respectively. Chapter Five discuses allylic afluoro aminoacids and their inherent instability. Chapter Six covers allylic a-aminophosphonates where the organocatalytic preparation of chiral vinylic phosphonates was achieved along with their amination-rearrangement, but the chirality transfer remains to be examined. Chapter Seven concludes our findings and outlines future research. Chapter Eight provides experimental details with spectroscopic and physical data for new compounds.

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The oxidation of olefins is of central importance in organic synthesis. This thesis is divided into the development of novel approaches to two classes of this transformation: (i) dihydroxylation and (ii) aminohydroxylation. (i) Dihydroxylation 1. Introduction- 1,2-Benzoquinones The chemistry of 1,2-benzoquinones is reviewed, including synthesis and reactivity; particular attention is paid to their cycloaddition chemistry and their reaction as hetero-dienes with alkenes. 2. Results and discussion - Utilising 1,2-benzoquinones as reagents for dihydroxylation The [4+2] reaction of 3,4,5,6-tetrachloro-I,2-benzoquinone as a hetero-diene with a range of alkenes to form the corresponding 2,3-dihydrobenzo[b][1,4]dioxines is studied. The reactivity of a sterically and electronically diverse range of 1,2-benzoquinones with representative alkenes is also studied. The cleavage of a 2,3-dihydrobenzo[b][1,4]dioxine to constitute overall syn-dihydroxylation of the alkene is investigated. (ii) Aminohydroxylation 3. Introduction - Osmium-mediated aminohydroxylation Development of the osmium-mediated aminohydroxylation is discussed, with particular emphasis on its mechanism and the development of an asymmetric variant. The tethered aminohydroxylation (TA) reaction is introduced, including discussion of its scope and limitations. 4. Results and discussion - Development of the osmium-mediated aminohydro~'Ylation reaction Tethered aminohydroxylation Optimisation of the standard TA protocol is investigated. An efficient synthesis of sulfonyloxycarbamate substrates for employment in a novel TA protocol is developed. The scope of the modified reaction is investigated in both allylic and homoallylic systems. Asymmetric aminohydroxylation (AA) The application of sulfonyloxycarbamates and benzoyloxycarbamates in AA reactions is studied, including extensive investigation of reaction conditions. 5. Introduction - MicroscIerodermins Synthetic approaches to the microsclerodermin family of natural products are reviewed. 6. Results and discussion - Towards the synthesis of the microscIerodermins A novel approach to the synthesis of the microsclerodermins utilising the TA reaction is disclosed, including the development of a protecting group strategy based on model studies. 7. Experimental Full experimental procedures and characterisation of compounds are reported.

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