This thesis describes the synthesis of some novel carbohydrate lactones and their uses as starting materials in (a) the syntheses of various polyfunctionalised cyclopentanes, via intramolecular aldol condensations, (b) the synthesis of 1-epihydantocidin, in which the crucial synthetic step involves a novel transformation induced by tetra-n-propylammonium perruthenate, and (c) the syntheses of various tetrahydrofurans and tetrahydropyrans. The syntheses of 3,4-O-isopropylidene and cyclohexylidene altrono and allono-1,5-lactones via Kiliani ascension of protected forms of D-ribose are described. The stereochemistry of the major reaction product, which was identified as 2,3-O-isopropylidene-D-altrono-l,5-lactone was confirmed by X-ray diffraction. Introduction of azide and iodide at C-2 is achieved via silyl protection of C-6 and formation of the 2-O-triflates. Nucleophilic displacement with azide or iodide produces mixtures of C-2 epimers. Desilylation is readily achieved by treatment with acetic acid to yield azido and iodo alcohols. Attempted oxidation of C-6 to an aldehyde functionality, in an attempt to effect cyclopentane formation via intramolecular aldol condensation of C-2 onto C-6 failed. Treatment of altrono and allono azido alcohols with tetrapropylammonium perruthenate unexpectedly results in the formation of a [2.2.2.] bicyclic hemiaminal, whose structure was confirmed by X-ray diffraction. Conversion of the amine functionality to a urea is effected by treatment with potassium cyanate. Cyclisation of the urea functionality onto the lactone carbonyl and subsequent deprotection effects the synthesis of 1-epihydantocidin. Investigations into acid catalysed epimerisation of the spiro centre in both hydantocidin and 1-epihydantocidin are described. Potassium carbonate induced ring contraction of 6-O-silyl altrono- and allono- 1,5-lactone-2-O-triflates yields tetrahydrofurans, the stereochemistry of which is confirmed by conversion to symmetric materials. Intramolecular Mitsunobu cyclisation of OH-2 onto C-6 of altrono-1,5-lactones effects tetrahydropyran formation. Inversion of C-5 of the known 3,4:5,6-di-O-ispropylidene-D-glycero-D-galacto-heptono- 1,5-lactone is described. Confirmation of product stereochemistry is achieved by conversion to 2,3-O-isopropylidene-L-altrono-1,5-lactone. Introduction of iodide and azide at C-2 is achieved via the formation of the 2-O-triflate. Selective deprotection of the 5,6 isopropylidene and subsequent periodate cleavage yields aldehydo lactones which undergo potassium fluoride induced intramolecular aldol cyclisation, to yield bicyclic [2.2.1.] azido and iodo carbocycles. Sodium azide induced intramolecular aldol cyclisation of 5-azido-5-deoxy-3,4-O-isopropylidene-L-galacturono-2,6-lactone, which produces two [2.2.1.] bicyclic azido carbocycles, is described. The second azido carbocycle, which is found to be the major reaction product, readily undergoes a retro aldol reaction, resulting in the formation of a third azido carbocycle, the structure of which was confirmed by X-ray diffraction. Investigations into the equilibration of these three bicyclic [2.2.1.] azido carbocycles under the reaction conditions employed to effect their formation are described. Various ring opening reactions of the second and third materials, and their uses in the syntheses of a novel amino pentol, two novel tetrahydroxy cyclopentane spirohydantoins and two novel cyclopentane amino acids are described. The structure of the asymmetric amino acid was confirmed by X-ray diffraction. Under basic reaction conditions retro aldol equilibration is seen to compete effectively with ring opening.

by Wai Ming Ho. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1995. / Includes bibliographical references (leaves 71-74). / ACKNOWLEDGEMENTS --- p.i / CONTENTS --- p.ii / ABSTRACT --- p.iv / Chapter I. --- INTRODUCTION --- p.1 / Chapter I-1. --- Liquid Crystal Mesophases --- p.1 / Chapter I-1-1. --- Mesophases --- p.1 / Chapter I-1 -2. --- Classification of liquid crystals according to molecular order --- p.1 / Chapter I-2. --- Ferroelectric Liquid Crystals --- p.6 / Chapter I-3. --- "The Relationship Among Spontaneous Polarization, Tilted Angle and Response Time" --- p.7 / Chapter I-4. --- Applications of Liquid Crystals --- p.8 / Chapter I-5. --- An Ideal Ferroelectric Liquid Crystal --- p.9 / Chapter I-6. --- Recent Development in Chiral Liquid Crystals --- p.10 / Chapter I-7. --- Aim of The Present Research: Chiral Liquid Crystals from Carbohydrates --- p.15 / Chapter II. --- RESULTS AND DISCUSSION --- p.17 / Chapter II-1. --- "Synthesis of 4',4""-Heptoxybiphenyl (methyl 2-O-n- butyl-3,4-dideoxy-a-D-glucopyranosid) uronate (12) and 4',4""-Cyanobiphenyl (methyl 2-O-n-butyl -3,4-dideoxy-a-D-glucopyranosid) uronate (13)" --- p.17 / Chapter II-2. --- "Synthesis of 4',4''-Heptoxybiphenyl (methyl 2-O-n- butyl-3,4-di-O-methyl-a-D-glucopyranosid) uronate (14) and 4' ,4""-Cyanobiphenyl (methyl 2-O-n-butyl -3,4-di-O-methyl-α-D-glucopyranosid) uronate (15)" --- p.33 / Chapter II-3. --- Mesomorphic Phases and Transition Temperatures of Chiral Liquid Crystalline Compounds 12 and 13 --- p.42 / Chapter III. --- CONCLUSION --- p.47 / Chapter IV. --- EXPERIMENTAL SECTION --- p.48 / Chapter V. --- REFERENCES --- p.71 / List of Spectra --- p.75 / Spectra --- p.76

by Ivan H.F. Chung. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1995. / Includes bibliographical references (leaves 63-67). / Acknowledgements --- p.i / Contents --- p.ii / Abstract --- p.iv / Abbreviations --- p.v / Chapter Chapter I --- Introduction / Chapter I-1. --- General background --- p.1 / Chapter I-2. --- Asymmetric Diels-Alder reaction using chiral auxiliaries --- p.2 / Chapter I-2A --- Some well-known chiral auxiliaries --- p.3 / Chapter I-2B --- Carbohydrates as chiral auxiliaries --- p.6 / Chapter I-3. --- Asymmetric Diels-Alder reaction using chiral catalysts --- p.10 / Chapter Chapter II --- Results and Discussion --- p.14 / Chapter II-1. --- "Synthesis of η6-(benzyl 2-O-acryloyl-3,4-O-isopropylidene- β-L-arabinopyranoside) tricarbonylchromium(O) (47)" --- p.15 / Chapter II-2. --- "Syntheses of 4'-methylbenzyl 2-O-acryloyl-3,4-O- isopropylidene-β-L-arabinopyranoside (57) and η6-(4'- methylbenzyl 2-O-acryloyl-3,4-O-isopropylidene-β-L- arabinopyranoside) tricarbonylchromium(O) (56)" --- p.19 / Chapter II-3. --- "Syntheses of naphthylmethyl 2-O-acryloyl-3,4-O- isopropylidene-α-L-arabinopyranosides" --- p.22 / Chapter II-4. --- Diels-Alder reaction using the dienophiles 56 and 57 as the chiral auxiliaries --- p.25 / Chapter II-5. --- "Synthesis of benzyl 3,4-O-methylene-β-L-arabinopyranoside (81)" --- p.32 / Chapter II-6. --- Using the alcohol 81 as the ligand for Lewis acid in the Diels-Alder reaction --- p.36 / Chapter Chapter III --- Conclusions --- p.38 / Chapter Chapter IV --- Experimental Section --- p.40 / Chapter IV-1. --- Experimental section for the asymmetric Diels-Alder reaction using the chiral auxiliaries --- p.41 / Chapter IV-2. --- Experimental section for the asymmetric Diels-Alder reaction using the chiral catalysts --- p.59 / References --- p.63 / List of spectra --- p.68

Wong Wai Fun. / "June 2006." / Thesis (Ph.D.)--Chinese University of Hong Kong, 2006. / Includes bibliographical references (p. 226-230). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in English and Chinese.

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The efficiency of an intermolecular synthetic transformation can be improved by temporarily linking reaction components together. The addition of a tether leads to enhanced regio- and stereocontrol by restraining the mobility of the reacting partners, effectively transforming an intermolecular reaction into its intramolecular counterpart. Silicon tethers are associated with an expanding range of applications, including hydrosilylations, cycloadditions and radical reactions. This project has continued work pioneered by the Robertson group into silicon tethered Type I ene cyclisations, extending the methodology to incorporate O-linked ene precursors with the intention of applying this chemistry to the stereoselective synthesis of non-natural carbohydrates. This investigation encompassed advances in the area made concurrently within the Robertson group and extended the scope of the ene protocol by successfully incorporating latent functionality into the R-group side chain. In addition, a new route to the O-linked ene precursors was established employing silylcyanohydrin chemistry. In general, the ene reactions proceeded stereoselectively to generate the expected oxasilacyclohexanols, which could be cleaved oxidatively to afford 1,2,4-triols. The formation of the major diastereomer was consistent with ene cyclisation proceeding through a trans-decalin type transition state (e.g. leading to compound 1). During our attempts to effect ene cyclisation in the O-linked prenyl systems we observed an unexpected side reaction, resulting from intramolecular allylic transfer. Further studies revealed that this novel process could be initiated thermally to generate 1,2-homoallylic diols with excellent levels of stereoselectivity. Tethered E- and Z-crotylsilanes were found to be equally receptive to this process. Although attempts to apply the silicon tethered allyl transfer chemistry to aldimines and glycosides failed, an extension of the methodology to incorporate cyclohexadienylsilanes was successful and provided interesting synthetic intermediates for elaboration to carbasugars.

A 5-membered INOC cycloadduct 84 was employed to prepare alcohol 91, which was transformed into several cyclopent-2-enone derivatives 94-96. / By using intramolecular nitrile oxide-alkene cycloaddition (INOC) as the kep step to construct hydroxylated carbocycles, gabosine F was synthesized for the first time from L-arabinose. Hence, theoretically, gabosine B, which is the enantiomer of gabosine F, can also be synthesized from D-arabinose by the same synthetic strategy. / In this thesis, the background information on the construction of carbocycles from carbohydrates via intramolecular 1,3-dipolar cycloaddition is presented. A review regarding the syntheses of gabosine B and cocaine are also descibed. / Starting with D-ribose, INAC of nitrones 113, 129, and 140, bearing an alpha/beta-unsaturated ester as the dipolarophile was studied. The INAC endo-cycloadduct 141 (cycloheptane) was converted into natural cocaine sucessfully, together with cocaine analogues 162,169,170,173,175, and 177. / The regioselectivity of intramolecular nitrone-alkene cycloaddition (INAC) was studied. The INAC of hept-6-enose nitrone 98, with a 3,4- trans-pentylidene acetal as the only blocking group, afforded endo-cycloadduct 97 (cycloheptane) exclusively. This result concluded that the regiospecific outcome of this INAC reaction is due to the present of the 3,4-trans-pentylidene acetal blocking group. / To investigate the regioselectivity in INAC of hex-5-enose with a 2,3- trans-pentylidene acetal blocking group, nitrones 178 and 195 were prepared from D-mannitol. endo-Cycloadducts (cyclohexanes) were afforded exclusively. / So, King Ho. / Adviser: Kung Ming Tony Shing. / Source: Dissertation Abstracts International, Volume: 73-06, Section: B, page: . / Thesis (Ph.D.)--Chinese University of Hong Kong, 2011. / Includes bibliographical references (leaves 165-171). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [201-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.

M.Sc. / The main objective of this project was to synthesize carbohydrates that contain a thiol functional group, commonly known as thiocarbohydrates and subsequently employ them as stabilizing agents in the synthesis of gold nanoparticles and as ligands in the synthesis of phosphine thiocarbohydrate gold(I) complexes. In achieving our objective, thiocarbohydrate compounds 62, 64, 69 and 71 were successfully synthesized from acetylated 60 or benzylated glucal 66 using a Ferrier rearrangement reaction. NaHSO4-SiO2 was used as a catalyst for Ferrier rearrangement reaction in the presence of dithiol type nucleophiles (i.e. 1,2-dithiol ethane or 1,5-dithiol pentane) to afford the desired thiocarbohydrate compounds. The S-acetate derivatives 63, 65, 70 and 72 of the corresponding thiocarbohydrates were prepared as a confirmatory test for the presence of the terminal thiol (SH) in the thiocarbohydrate compounds. C-2 modified thiocarbohydrate compounds 78 and 80 were synthesized from C-2 iodomethyl glycoside 77 following a literature reported procedure in the presence of 1,2-dithiol ethane or 1,5-dithiol pentane as nucleophiles. S-acetate derivatives 79 and 81 of the corresponding thiocarbohydrate compounds were synthesized again to confirm the presence of the terminal thiol (SH). All the thiocarbohydrate compounds and their corresponding S-acetate derivatives were characterized with NMR spectroscopy and HRMS. Ethyl thiocarbohydrate compounds 62, 69 and 78 were successfully employed as stabilizing agents in the preparation of gold nanoparticles GNP1-GNP9 following a Brust-Schiffrin procedure. UV-Vis spectroscopy and transmission electron microscopy (TEM) were used to characterize these gold nanoparticles. Phosphine thiocarbohydrate gold(I) complexes 84-94 were synthesized from selected thiocarbohydrate compounds. NMR spectroscopy and HRMS were used to characterize these gold(I) complexes. Having synthesized the target thiocarbohydrate compounds, gold nanoparticles and gold(I) complexes, our aim was to investigate their biological activity against cancer and HIV. However, the biological testing process took considerably longer and as a result this dissertation was submitted without the biological tests results.

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