Thesis (Ph. D.)--McMaster University (Canada), 1988. / Source: Dissertation Abstracts International, Volume: 49-11, Section: B, page: 4824. Supervisor: R.A. Bell.

A new synthetic route to cyclophanenes 56, starting from an appropriate 2,6-dihalogen-substituted toluene via monothiacyclophanes as intermediate compounds, was developed. By this method, anti-5,8,13-16-tetramethyl [2,2] (1,3)cyclophan-1-ene, 56b, and anti-4,6,8,12,14,16-hexa-methyl [2,2] (1,3)cyclophan-1-ene, 56c, were first synthesized as well as three new monothiacyclophanes, anti-9,17-dimethyl-2-thia [3,2] (1,3) cyclophane, 72a, anti-6,9,14,17-tetramethyl-2-thia [3,2] (1,3) cyclophane, 72b, anti-5,7,9,13,15,17-hexamethyl-2-thia [3,2] (1,3) cyclophane, 72c. An X-ray structural determination of the monothiacyclophane 72a revealed an anti-stepped geometry of the molecule and that the aromatic rings were bent outward in a slightly distorted boat form. A reciprocal relationship between deviations of the inner carbons from their basal planes and distances between the inner carbons was found by comparison of X-ray data of four metacyclophanes. Several tricarbonylchromium(0) and η5-cyclopentadienyl-iron(I) complexes of cyclophanenes 56 were also prepared for the first time. The complexation effect and ring current reduction effects in these complexes were investigated through studies of their proton nmr spectra. An X-ray structure analysis of anti-8,16-dimethyl [2,2] (1,3) cyclophan-1-ene-cyclopentadienyliron(I), 105a, was determined and it was found that the bridge double bond (1.345A) has a cis geometry but with very large torsional angles: 24.7° for C-C=C-C and 41.6° for H-C=C-H. The bridge chemistry of cyclophanenes 56 and their metal complexes was investigated through some selected reactions. It was found that the cyclophanenes 56 were easily oxidized in attempted electrophilic additions to the bridge double bond. Bromination of the cyclophanene-iron complexes 105b and 105c did give the desired bromine adducts. However, it was found that the reactivity of the bridge double bond in cyclophanenes 56 is very low since most of the attempted reactions failed to give the desired products. The first synthesis of the (η6, η6-anti-4,6,8-trimethyl [2,2] (1,3) cyclophan-1,9-diene)-bis(tricarbonylchromium(0)), 133, was achieved through the dithiacyclophane route. An X-ray structure analysis of 133 was also determined and found that the two aromatic rings were inclined at 19.8° with respect to each other. / Graduate

Isobenzofurans (IBF)s are interesting molecules with regards to their structure and reactivity. The properties of these compounds are investigated through the use of gas phase calculations and kinetic studies. This work provides insight into the aromatic character of IBF and how substituents affect IBF’s reactivity. Substituted derivatives of naphtho[1,2-c:5,6-c]difuran are synthesized and reacted with tethered bis(dienophile)s to form cyclophanes. Phenyl-substituted naphtho[1,2-c5,6-c]difuran forms only a single isomer when reacted with a tethered bis(acrylate) and a tert-butyldimethylsilyl-substituted derivative exhibits higher selectivity towards cyclophane formation rather than polymer formation. Evidence for strong intramolecular interactions within these cyclophanes is presented as well. A five-step synthesis of anthra[1,2-c:7,8-c]difuran is developed, although with a poor overall yield. Similar reaction conditions could be applied to the synthesis of anthra[1,2-c:5,6-c]difuran. We also propose the synthesis of two different aromatic belts from these compounds. / xxii, 122 leaves : ill. ; 29 cm.

The synthesis of 1,2-bis(5-isobenzofuranyl)ethene by two routes is described. The first route involved generation of 1,2-bis(5-isobenzofuranyl)ethene from a bis(acetal) precursor under basic conditions. However, the synthesis was lengthy with low-yielding steps, which led to it being abandoned. The second route involved generation of 1,2-bis(5-isobenzofuranyl)ethene from a bis(oxabicyclic) precursor with 3,6-di(2'-pyridyl)-s-tetrazine. Napththo[1,2-c:5,6-c] difuran and 1,2-bis(5isobenzofuranyl)ethene were used to construct novel cyclophanes by double Diels-Alder reactions with bis(maleimide)s. NMR, AM1 modeling, and X-ray studies of the cyclophanes are discused. Attempts to prepare phenanthro[2,3-c:6,7-c] difuran and its cyclophanes are discussed. None was successful, and investigations were hampered by the inability to obtain sufficient quantities of starting materials. Finally, several suggestions are given for improving the syntheses of 1,2-bis(5- isobenzofuranyl)ethene, phenanthro[2,3-c:6,7-c]difuran, and their cyclophanes. Future directions, such as the functionalization of the double bond of 1,2-bis(5-isobenzofuranyl)ethene, aromatization of the oxabicyclic rings of the cyclophanes, and further X-ray studies are discussed. / x, 122 leaves : ill. ; 28 cm.

Isobenzofuran has since its discovery proven an important intermediate in the synthesis of novel organic compounds, due to its high reactivity in Diels-Alder reactions. This thesis details the synthesis, purification and characterization of cyclophane compounds derived from a novel analogue of isobenzofuran, 5,5'-bi(isobenzofuran). Because of the relative rarity of molecules containing multiple isobenzofuran units, 5.5'-bi(isobenzofuran) is an excellent candidate for study. Prelminary analysis of an additional novel analogue of isobenzofuran, 5.5'-bis(isobenzofuranyl) acetylene, is also presented. / x, 119 leaves : ill. ; 29 cm.

Thesis (Ph.D.)--Memorial University of Newfoundland, 2000. / Includes bibliographical references.

Thesis (Ph.D.)--Memorial University of Newfoundland, 2003. / Includes bibliographical references.

La réaction de macrocyclisation par métathèse est une réaction clé en synthèse organique et qui comporte de nombreux défis. Les méthodes traditionnelles de macrocyclisation impliquent par exemple la haute dilution du mélange réactionnel et l’emploie d’une pompe seringue. Dans cette thèse de doctorat, une méthode qui évite l’emploi des techniques de haute dilution a été développée. Cette méthode a été appliquée à la synthèse de cyclophanes macrocycliques. De plus, la synthèse totale de la néomarchantine A, un macrocycle bisbibenzylique, a été réalisée en 12 étapes à partir de produits commercialement disponibles avec un couplage d’Ullmann, un couplage de Wittig et une macrocyclisation par métathèse comme réactions clés. La chimie en débit continu, une méthode facilement applicable en milieu industriel, a été explorée. Cette technologie a été appliquée à l’étape clé de macrocyclisation par métathèse pour la synthèse de la néomarchantine A ainsi que pour la synthèse d’un musc macrocyclique breveté par la compagnie « International Flavors and Fragrances (IFF) ». / The macrocyclic metathesis reaction is a key reaction in organic synthesis and possesses numerous challenges. Traditional methods typically involve high dilution conditions and the use of a syringe pump. In this doctoral thesis, a method that avoids the use of dilution technics has been developed. This method has been applied to the synthesis of macrocyclic cyclophanes. Furthermore, total synthesis of neomarchantin A, a bisbibenzyl macrocycle, has been done in 12 steps from commercially available reagents with an Ullmann coupling, a Wittig coupling and a macrocyclic metathesis reaction as key steps. Continuous flow chemistry, a method easily applicable in an industrial setting, has been explored. This technology was applied to the key macrocyclization step of the neomarchantin A and for the synthesis of a macrocyclic musk patented by International Flavors and Fragrances (IFF).

Only within the last decade has supramolecular chemistry begun to adopt the Group 15 elements into its field of research. This dissertation presents a supramolecular approach to the self-assembly and reactivity of Group 15 metalloids, specifically arsenic and antimony, with organothiolate ligands. Investigating the self-assembly of pnictogen-based coordination complexes allows for in-depth characterization of the chemical behavior of arsenic, antimony and other Group 15 elements. Currently, the infiltration of arsenic into global groundwater systems has developed into a worldwide health concern. There are no chelating agents available for public use in the treatment of arsenic poisoning which are capable of binding arsenic (III) in its preferred coordination geometry thereby hindering the selectivity for rapid chelation. Chapter I is a review covering two important characteristics observed in the Group 15 elements: 1) a stabilizing, non-covalent cation-π interaction aiding in the formation of pnictogen-aryl thiolates, and 2) an observed lack of selectivity in environments containing multiple pnictogen ions which enables transmetalation of the complexes to occur or the generation of heterometallic assemblies. Based on the discovery of this new transmetalation reactivity, the remainder of the dissertation explores the effects of external additives during self-assembly in order to understand how they may affect the reactivity of these self-assembled complexes and provide insight into formation mechanisms. Chapter II identifies a catalyst for the acceleration of a slow self-assembly reaction between AsCl3 and a dithiolate ligand to give an As2L3 cryptand. Chapter III examines the oxidation of the arsenic cryptand using iodine, which leads to the self-assembly of a series of differently sized, discrete disulfide-bridged macrocycles. In Chapter IV, the self-assembly of the first trinuclear arsenic- and antimony-based coordination complexes was studied, revealing interesting solvent dependent conformational isomerism in solution. Chapter V applies the pnictogen-enhanced iodine oxidation to the synthesis of known and new cyclophanes using supramolecular chemistry, including the self-assembly and covalent capture of an unprecedented tetrahedral thiacyclophane. Additionally, an unusual trithioorthoformate capped tricyclophane cage was also synthesized and isolated by pnictogen-activated oxidation. Chapter VI includes the conclusion and future directions for the project. This dissertation includes co-authored material and previously published results. / 10000-01-01

Thesis (Ph.D.)--McMaster University (Canada), 1993. / Source: Dissertation Abstracts International, Volume: 54-12, Section: B, page: 6203. Adviser: Russell A. Bell.