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This work demonstrates the use of a Diels-Alder/retro Diels-Alder approach using a chiral anthracene auxiliary to control the stereochemistry of subsequent reactions. A range of N-substituted maleimide cycloadducts have been prepared and asymmetric transformations undertaken to give N-acyliminium ion precursors. N-Acyliminium ions have been formed under standard conditions and a range of nucleophiles used to form tertiary and quaternary stereocentres. For the synthesis of polycyclic heterocycles, a N-[2-(6-methoxypyridin-2-yl)ethyl] cycloadduct was prepared in 3 steps from commercially available starting materials. Asymmetric transformations were carried out; reduction and Grignard addition to form hydroxy-lactams both in high yield with high selectivity. The N-acyliminium ion was then formed for both systems but unfortunately, due to the inherent electron poor nature of the pyridine ring, even with an activating methoxy group, no ring formation occurred and side products predominated. For the synthesis of natural product comosidine, a N-(3,4-dimethoxyphenylpropyl)maleimide cycloadduct was prepared in high yield and a range of nucleophiles added to prepare hydroxy-lactam analogues. When subjected to Friedel-Crafts conditions in an attempt to form a 7 membered ring, no cyclisation took place. In fact, intramolecular Friedel-Crafts additions were shown to be highly dependent on the ring size that is being formed when using a dimethoxyphenyl group as nucleophile. Indeed the 6 membered ring is the only size that will form. Attempts to make 5, 7 and 8 membered rings by this method are not viable, and computational studies show the desired FriedelCrafts products are relatively less stable than the alkenes that are indeed formed experimentally for the 7 and 8 ring analogues. Intermolecular Friedel-Crafts reactions have also been undertaken using nucleophiles such as furan, thiophene and indole, accessing tertiary stereocentres (seven examples in 54 - 100% yield) and quaternary stereo centres (five examples in 50 - 100% yield). Retro Diels-Alder reaction of furan addition cycloadduct containing a quaternary stereocentre yielded a substituted maleimide derivative in 100% yield and 97% enantiomeric excess. This demonstrates the use of this strategy to construct quaternary stereo genic centres. A further attempt to prepare comosidine used a Parham cyclisation; using an aryl iodide to form the desired 7 membered ring. This proved to be very successful and gave the corresponding hydroxy-lactam in high yield. Addition of carbon nucleophiles such as silyl enol ethers, were then tested on a range of substituted N-acyliminium ions to prove the overall methodology before application to the natural product. Three examples with tertiary stereocentres were prepared in 97 - 98% yield and four examples with quaternary stereocentres formed in 78 - 95% yield, exclusively. The nature of the Nacyliminium ion itself has found to be very important. If the iminium ion is unstabilised, nucleophilic addition is relatively facile. However, if a stabilising group is attached such as a phenyl ring, attack is much more difficult and harsher reaction conditions are needed. The N-acyliminium ion formed for comosidine was found to be very stable and therefore would not react with any nucleophile tested. Several ideas to overcome the stability and unreactivity of very electron rich N-acyliminium ions have been investigated. Finally, the formal synthesis of (+)-hygrine has been completed by use of the methodology; using addition of acetone to the N-acyliminium ion formed from Nmethylmaleimide hydroxy-lactam in 100% yield. Other steps including cycloreversion, hydrogenation and amide reduction gave the enantioenriched protected natural product in 7 steps from 9-(1-methoxyethyl) anthracene auxiliary and N-methyl maleimide.

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Describes investigations in three areas of aromatic chemistry, namely, the preparation and properties of aromatic organoboron compounds, the reactions of carbonyl compounds with aromatics, and the structure and synthesis of naturally occurring carbonyl compounds. The papers cover an extended period, from 1955 to 2003, during which time spectroscopic techniques developed greatly.  The early work did not have the advantage of modern NMR and MS techniques let alone X-ray crystal structure determination and had to rely on the limited structural information provided by UV and IR measurements.

The interactions of some aromatic nitro-compounds with nucleophiles in protic solvents and in protic-dipolar aprotic solvent mixtures have been investigated using the techniques of proton magnetic resonance and visible spectroscopy and stopped-flow spectrophotometry. The rates of reaction (nucleophilic reactivities) of a series of substituted thiophenoxide ions with l-chloro-2,4-dinitrobenzene in 95/5 (v/v) ethanol-water, determined by a stopped-flow spectrophotometric method, correlate better with their carbon basicities than with their proton basicities. In methanol 4-methoxy-3,5-dinitrobenzaldehyde is in equilibrium with its hemiacetal formed by solvent addition to the carbonyl function of the aldehyde group, the equilibrium constant for hemiacetal formation (= 8) being obtained from p.m.r. measurements. In the presence of methoxide ions Meisenheimer complex formation occurs by base addition to the parent aldehyde. Kinetic and equilibrium data are reported for complex formation in methanol. In dimethyl sulphoxide there is straightforward formation of Meisenheimer complex. The formation of 1:2 adducts from l-X-2,4,6-trinitroberizenes (X = OMe, OH, NH(_2), NHMe, NMe(_2)) and sodium sulphite in water is characterised by only one relaxation time. P.m.r. measurements also indicate the existence of one isomer of the 1:2 adduct at equilibrium. However when X = H such measurements reveal the presence of both cis- and trans-isomers. Ring-activated glycol ethers cyclise in the presence of aqueous base to give spiro-complexes. Equilibrium and kinetic parameters for complex formation and decomposition are much higher than the corresponding values for their non-cyclic analogues. The spiro-complexes derived from 1-(2-hydroxyethoxy)-2,4,6- trinitrobenzene and -2,4-dinitronaphthalene undergo general acid catalysed decomposition. On going from spiro-complexes which contain 5- to those which contain 6- and 7-membered dioxolan rings there is a dramatic decrease in complex stability.

This thesis is divided into two parts. The first part begins with a concise introduction (Chapter 1) into the crystallographic theory that underpins much of the work that is presented in later chapters. In Chapter 2， the crystal structures of eight aromatic sulphonate compounds are discussed in detail. These structures form a series, and the packing arrangements for each have been scrutinised using graph-set analysis; this allows for common structural patterns to be identified, and for conclusions to be drawn in relation to the solid-state packing behaviour for this class of compounds. A crystallographic study of a number of phosphorus ylide compounds is reported in Chapter 3. Phosphorus ylides are of fundamental importance as reagents for a number of key synthetic reactions, and the aim of the study was to establish a deeper the first examples of uranium(VI)-ylide complexes are reported. Part 2 of this thesis commences with a general introduction to coordination polymer complexes and gas-storage materials (Chapter 4). The structural features and physical (Zn40(BDC)) that is central to the work presented in the following chapters are discussed. In Chapter 5, a variable temperature single crystal X-ray diffraction study of nitrogen- and argon-loaded Zn40(BDC) is presented. The aim of this ambitious project was to locate the absorption sites for the physically absorbed gas that are located within the cavities of the framework architecture. This work laid the foundation for the neutron Laue diffraction study of hydrogen-loaded Zn40(BDC) that is reported in the final chapter (Chapter 6). This neutron study represents the first example of the use of neutron diffraction for the location of physically absorbed gas within a host structure. The results given in Chapters 5 and 6 are of vital importance for the development of Zn40(BDC), and similar complexes, for gas-storage and purification applications.

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