Thesis (Ph. D.)--University of Michigan, 1934. / "By W.E. Bachmann and Helen R. Sternberger." "Reprint from the Journal of the American chemical society, 55 ... (1933); 56 ... (1934)."

Thesis (Ph. D.)--University of Chicago, 1934. / Lithoprinted. "Private edition, distributed by the University of Chicago Libraries, Chicago, Illinois."

Thesis (M. Sc.)--York University, 2001. Graduate Programme in Chemistry. / Typescript. Includes bibliographical references (leaves 85-90). Also available on the Internet. MODE OF ACCESS via web browser by entering the following URL: http://wwwlib.umi.com/cr/yorku/fullcit?pMQ71609.

Crystal structures of anhydrous pinacol, the hexagonal pinacol, pinacol monohydrate, and pinacol hexahydrate were studied. In all the structures crystal packing is unusual and complicated. The origin of the complexity may be the difficulty in filling space densely and while also satisfying the H-bonding requirements when the molecule has few internal degrees of freedom. Five 15-crown-5 complexes of M(NO3)2 (M = Cu, Zn, Mg, Co, Mn) were synthesized and characterized using X-ray diffraction and differential scanning calorimetry. The system is rich in polymorphs. Nine definite solid-state phases were identified. More phases probably exist in the solid state at temperatures slightly above the room temperature. Most phase transformations in this system take place in single crystals without the loss of crystallinity. The nine phases crystallize in five crystal structures. The crown ether ligands have very similar conformation in all the structures. The asymmetric units in all the structures are complicated and pseudosymmetric, which is the consequence of the presence of the packing problem. The origin of the packing problem that leads to the complicated phase behavior is the odd number of -CH2-O-CH2- units in the crown ether ligand.

In our previous publication of Thiele cage diols, we describe the first pinacol rearrangement to occur over a C(sp3)–C(sp3). Two mechanisms were initially proposed: a concerted mechanism and a stepwise mechanism, proceeding through a carbocation intermediate. Interestingly, the rearrangement provides only a single diastereomer. The aim of this thesis is to investigate the nature of the reaction by measuring the relative rates of reaction with varying substituents that either stabilize or impede the formation of carbocations. From the relative rates, we can narrow in on whether the mechanism is stepwise or concerted, based on substituent effects, and determine how the reaction may provide a single diastereomer. In Chapter 1, the pinacol rearrangement is introduced, and each analogue that followed after, including stereoselective pinacol rearrangements and a series of different semipinacol rearrangements that provide useful synthetic pathways for chemists with desirable stereochemical outcomes. In Chapter 2, we describe the isolation and characterization of two analogues of a key side product. The structure of each analogue was determined through a series of spectroscopic techniques including 1H-1H COSY, HSQC, HMBC, and 1D-selective gradient NOE NMR. From the solved structures, we proposed a possible mechanism to describe their formation during the main rearrangement reaction – one that shares a carbocation intermediate with the stepwise mechanism already proposed. In Chapter 3, we prepared five Thiele cage diol analogues with aryl substituents with different electronic properties: two substituents that stabilize carbocation intermediates (p-OCH3 and p-CH3), two that destabilize (p-F and 3,5-diOCH3), and the base tetraphenyl Thiele cage diol. We measured the rates of reaction of each diol with p-toluenesulfonic acid at 25°C, 35°C, 45°C, and 52°C via variable temperature quantitative 1H-NMR over time. From the rates of reaction, we found that diols with carbocation-stabilizing aryl substituents reacted faster than the destabilizing analogues, providing evidence that the rearrangement proceeds through a carbocation intermediate. We also found that the diols with electron-deficient aryl substituents showed an increase in the entropy of activation with increasing electron-deficiency in the aryl groups, suggesting an associative pathway for the electron-deficient substituents toward the rearrangement product. Considering the pathway proposed for the side product, we propose an updated stepwise mechanism. Based on computational studies and a previously-isolated X-ray crystal structure, we determined that the diastereoselectivity of the reaction was facilitated by favourable π-π stacking interactions between two aryl substituents. The interaction of the aryl groups twists the geometry of the molecules, placing the migrating aryl substituent in the ideal position for the rearrangement to occur stereoselectively. / Graduate / 2023-10-31

Asymmetric synthesis and catalysis is one of the leading research areas in chemistry society, for its versatility and efficiency in obtaining chiral molecules that found the vast majority in natural active compounds and synthetic drugs. Developing asymmetric catalytic methodology is at the frontier in both industrial and academic research laboratories. Enantioselective organocatalysis has emerged as a powerful synthetic tool that is complementary to metal-catalyzed transformations. The development of chiral phosphoric acid and metal phosphate as catalysts has been a breakthrough in recent years. Chiral phosphoric acids have been shown to be powerful catalysts in many organic transformations. Moreover, chiral metal phosphates, which formed by simply replacing the proton in phosphoric acid with metals, have introduced new catalytic activations and broaden the scope of phosphoric acids. This thesis details new highly enantioselective chiral phosphoric acid-catalyzed Pinacol rearrangement and robust alkaline phosphates catalytic system, which utilizes novel carbonyl activation. The Pinacol rearrangement has long been known to be difficult to control in terms of regioselectivity and stereoselectivity. The initial studies found that indolyl-diol compounds can be treated with chiral phosphoric acids to afford the Pinacol rearrangement with high regio- and enantioselectivity. Over 16 chiral phosphoric acids were screened, and it was found an H8-BINOL-phosphoric acid variant with 1-naphthyl groups at 3 and 3' position was the excellent catalyst. This asymmetric transformation is tolerant toward variety of substituents both on the indole ring and migrating groups. During the study, it was found that different ways to generate the catalyst had critical effect on this catalytic transformation. Only those phosphoric acids washed with HCl after column chromatography afforded the rearrangement products with high enantioselectivity. And those without treating with HCl were found contaminated by alkaline metals. These "contamination" catalysts were also found active with carbonyl activations. A highly enantioselective catalytic hetero-Diels-Alder reaction of alpha-keto esters has been developed with chiral alkaline metal phosphates. A calcium 1-naphthyl-BINOL phosphate was found to be the optimum catalyst. A large range of alpha-keto esters as well as isatins can be applied in this alkaline phosphates catalytic system with high efficiency and selectivity. The structure of the catalyst is detailed for the first time by X-ray crystal structure analysis. A proposed Transition state model is provided based on the catalyst crystal structure and Raman spectroscopy analysis. This methodology was further developed with an asymmetric Mukaiyama-Michael addition of beta,gamma-unsaturated alpha-keto ester. The best catalyst was found to be a magnesium chiral phosphate. And the transformation was found capable of tolerating a wide variety of beta,gamma-unsaturated alpha-keto esters.

No description available.

Les travaux de recherche présentés ici ont pour objectif la synthèse de fongicides innovants de la manière la plus éco-compatible qu’il soit. Pour cela, plusieurs axes de réflexion ont été étudiés. Tout d’abord, la synthèse d’un intermédiaire de fongicides bien connu, l’o-crésol1, a été réalisée à partir d’un substrat naturel, le salicylaldéhyde2. Les conditions expérimentales ont été éco-conçues afin de correspondre au mieux aux exigences de la chimie verte. Des solvants et des réactifs classés verts ont été utilisés, comme l’éthanol, l’eau et l’acide acétique3 par exemple, ainsi que des techniques alternatives comme l’activation par micro-ondes (Schéma 1). Dans un second temps, des synthèses éco-compatibles de nouveaux fongicides ont été réalisées. Le salicylaldéhyde, substrat naturel de référence, a été mis à réagir avec différents alcools afin de réaliser des réactions d’éthérifications réductrices. Les molécules obtenues sont composées d’une partie phénolique portant un groupement alcoxyle en position 2. Ce groupement alcoxyle se compose d’une longueur de chaîne variable ayant une influence sur les propriétés fongicides des produits synthétisés (Schéma 1). Troisièmement, des réactions d’homo- et d’hétéro-couplages pinacoliques ont été réalisées entre divers aldéhydes, aromatiques et aliphatiques, afin d’obtenir des diols vicinaux, appelés pinacols, symétriques ou non (Schéma 1). Dernièrement, les propriétés fongicides et anti-oxydantes de toutes les molécules obtenues de manière stable, référencées ou non, ainsi que les substrats de départ, ont été testés. Les tests microbiologiques ont été réalisés sur une gamme de diverses souches fongiques. / The purpose of this research is to synthesize innovative fungicides by the most ecocompatible way. Several hypotheses have been investigated. First, an extensively studied molecule, intermediate of fungicides, o-cresol1, has been achieved from a natural substrate, salicylaldehyde2. The experimental conditions have been eco-designed in the aim to best match green chemistry requirements. Green solvents and reactants have been used, as ethanol, water and acetic acid3 for example, as well as alternative technologies like microwaves activation (Schema 1). Secondly, novel fungicides green syntheses have been carried out. Salicylaldehyde, a natural substrate model, reacted with various alcohols in the aim to perform reductive etherification reactions. In this way, products were composed of phenolic part with an alkoxyl group at the 2nd position. These alcoxyl groups have various chain lengths, playing a key role in fungicidal ability (Schema 1). Then, homo and hetero pinacol coupling reactions have been achieved with various aromatic or aliphatic aldehydes to obtain symmetrical and asymmetrical vicinal diols, called pinacols (Schema 1). At last, fungidal and antioxidant properties of all stable obtained molecules, referenced or not, as well as starting materials, have been evaluated. Microbiological studies have been carried out with various fungal strains.

L'utilisation de composés organométalliques pour le traitement des cancers est l'un des domaines de la chimie bioorganométallique qui connait une expansion rapide. Parmi les composés développés en endocrinologie, les composés les plus intéressants et très étudiés sont les dérivés ferrocéniques du tamoxifène. Ils sont développés par le groupe du Professeur Gérard Jaouen. Parmi ces composés, le ferrocifène et le ferrociphénol sont très actifs contre les cellules cancéreuses hormono-dépendantes (MCF-7) et hormono-indépendantes (MDA-MB-231) du cancer du sein. Le ferrocénophanyl diphénol, un dérivé phénolique de la série ferrocénophane et analogue du ferrociphénol, s'est montré plus actif que celui-ci. Dans le but de verifier cette caractéristique et aussi de trouver de meilleures molécules, de nouveaux composés de la série ferrocénophane ont été synthétisés et étudiés. Les nouveaux composés sont des 1-(diarylméthylidène)-[3]ferrocénophanes, portant un ou deux substituants (R1, R2 = H, OH, OAc, NH2, NHAc, Br, CN, NHCO(CH2)2NMe2, O(CH2)3NMe2 ou O(CH2)2COOEt) en para du cycle aromatique. L'activité antitumorale de ces composés prouve que la série des ferrocenophanes est plus efficace que la série des ferrocènes contre les cellules cancéreuses du sein. Les études ont été également menées sur les pinacols et les produits résultant de l'arrangement pinacolique. Ces deux produits ont été péparés à partir de la réaction de couplage de McMurry. On trouve que les pinacols sont très actifs contre les cellules cancéreuses MDA-MB-231. Cependant les produits de transposition sont peu réactifs. Ce travail montre que la série des ferrocénophanes est plus efficace que la série des ferrocènes contre les céllules cancéreuses du sein.