Les composés deutérés sont d’un intérêt grandissant dans des domaines variés. Par exemple, en pharmacologie, l'échange H/D peut améliorer les propriétés pharmacocinétiques de certains médicaments ou réduire leur toxicité. Les composés deuterés peuvent également être utilisés comme étalons internes en spectroscopie de masse. Il est donc important de trouver un moyen simple et sélectif d'échanger l'hydrogène avec le deutérium sur des molécules d’intérêt biologique. Les nanoparticules, de ruthénium en particulier, se sont révélées être des systèmes efficaces pour catalyser cet échange. Cependant, étant très actives, elles conduisent souvent à la réduction de substrats aromatiques. L'objectif principal du doctorat est l’élaboration de nouvelles nanoparticules permettant de contrôler la réactivité en échange isotopique H/D. Nous avons d’abord synthétisé des alliages Ru-Pt afin d’introduire du platine, moins actif en échange H/D, et donc empoisonner la surface du Ru. Nous avons montré qu’en changeant le précurseur de platine, on pouvait changer la distribution atomique de surface, et ainsi moduler la réactivité des nanoparticules. Nous avons finalement synthétisé des nanoparticules de nickel et d'iridium. Ces nanoparticules se sont avérées être des catalyseurs efficaces pour l'échange H/D, sans réduction de fonctions aromatiques. De plus, des sélectivités différentes ont été obtenues en fonction du métal utilisé. / Deuterated compounds are molecules of great interest in various fields. In pharmacology, the H/D exchange can improve the pharmacokinetic properties of some drugs or reduce their toxicity. In addition, deuterium-labelled compounds can be used as internal standards for mass spectroscopy, or as tracers for the understanding of different reaction mechanisms. Therefore, it is important to find a way to exchange hydrogen with deuterium in a simple, selective and efficient way. The main goal of the PhD project is the synthesis of novel nanoparticles for isotopic exchange (H/D). Metal nanoparticles and more particularly ruthenium nanoparticles, has shown their efficiency to catalyze this exchange. However, ruthenium nanoparticles are very active in arene hydrogenation, and often lead to the reduction of aromatic substrates. In a second part of the work, we synthesized Ru-Pt alloys in an attempt to passivate the Ru surface with platinum, which is less-active in H/D exchange. We have shown that by changing the platinum precursor, we can change the atomic distribution of the surface, and thus we were able to modulate the reactivity of nanoparticles. We finally synthesized Ni and Ir nanoparticles. These nanoparticles have proven to be efficient catalysts for H/D exchange, without reducing aromatic functions. In addition, different selectivity was obtained depending on the metal used.

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<div>Mass spectrometry (MS) is a powerful and versatile analytical tool, especially for identification and analysis of complex mixtures. Coupling to high-performance liquid chromatography (HPLC) or gas chromatography (GC) provides additional dimension for mixture analysis. MS manipulates ionized analytes and separates them based on their mass-to-charge (<i>m/z</i>) ratios. MS is capable of providing molecular weight (MW) information by generating pseudo-molecular ions of the analytes. Detailed elemental compositions can be also obtained if high resolution MS is used. MS can also provide extensive structural information of the analyte ions. One of the most commonly used technique is tandem mass spectrometry (MSⁿ). Ions of interest are isolated and subject to sequential reactions (reactions with other molecules or dissociation reactions) to generate product ions that can provide structural information. MS is also a powerful tool for generating and studying highly reactive reaction intermediates, such as organic polyradicals.</div><div><br></div><div>The research described in this dissertation mainly focuses on the generation and gas-phase reactivity studies of different organic biradicals. Their reactions with various organic reagents are studied, and the reactivity-controlling factors are discussed. For example, the reactivity of several substituted pyridine-based biradical cations with 2,6-topology are discussed (all with singlet ground states), and their special reactivity from their excited triplet states are illustrated. Besides, several quinoline-based biradicals and cyano-substituted pyridine-based <i>para</i>-benzyne cations are also discussed. Some of the radicals (or ions) described in this dissertation are generated for the first time, i.e. the quinoline-based oxenium cations. Their structural characterization and gas-phase reactivity toward some organic molecules are discussed in the dissertation. Further, an electrophilic anion, <i>closo</i>-[B₁₂X₁₁]^- (X = Cl, Br) and its application in the activation of C-H and C-C bonds in hydrocarbon molecules are described in the dissertation.</div>

Pendant de nombreuses années, les liaisons C-H aliphatiques ont été considérées comme dormantes, difficilement exploitables dans le contexte de la chimie organique. Le défi le plus important est de sélectionner une liaison C-H parmi toutes celles que contient une molécule. L’approche la plus utilisée à ce jour est l’utilisation d’un groupement directeur qui permet, en se liant à un métal, de diriger l’activation d’une liaison C-H en particulier. Suite au développement des groupements bicoordinants, nous avons développé notre propre groupement bicoordinant chiral. Cet auxiliaire nous a permis de réaliser de nombreuses transformations diastéréosélectives sur des carbones aliphatiques telles que l'arylation et l'oléfination. Nous l’avons également utilisé pour développer une méthodologie innovante pour la synthèse de produits naturels. Suite à ces travaux, nous avons développé un nouveau ligand chiral qui a été utilisé dans l’arylation et l’alkynylation énantiosélectives de cycloalcanes. / Over the decades, non-activated C-H bonds have been considered as dormant functionalities, hardly exploitable in the context of multistep synthesis of complex scaffolds. The main challenge is to select one C-H bond among all contained in one molecule. To answer to this problem bicoordinating directing groups allowing directed C(sp3)-H activation have been developed. Following the work of Daugulis and Babu, we developed our own chiral bicoordinating directing group, (S)-2-(p-tolylsulfinyl)aniline. This chiral auxiliary allowed us to realise various diastereoselective transformations on aliphatic chains such as arylation, olefination oracetoxylation. We also used it to develop a brand-new methodology for the total synthesis ofcyclopropane-bearing natural products. Moreover we developed a new chiral sulfinyl ligand, N-((S)-1-(4-(tert-butyl)phenyl)-2-((R)-p-tolylsulfinyl)ethyl)acetamide, that has been used for the enantioselective arylation and alkynylation of cycloalkanes.

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Résumé : Au cours de ce travail, nous avons effectué une étude méthodologique concernant la synthèse d'azobenzènes tétrasubstitués en position ortho pour mieux comprendre les éléments affectant leurs synthèses, généralement inefficaces, et afin d'en améliorer les rendements. Nous avons conclu que l'inefficacité de cette synthèse est causée par des effets stéréoélectroniques : l’effet stérique du substituant en position ortho, qui s’ajoute à l’effet électronique du groupement en position para. Après différentes optimisations, nous avons réussi à synthétiser un azobenzène tétrachloré et un azobenzène tétrafluoré via un intermédiaire nitrosobenzène avec de bons rendements.Le dérivé tétrafluoro azobenzène a été ensuite fonctionnalisé en introduisant une chaîne alcyne terminée par un groupement maléimide afin de permettre sa fixation sur un résidu cystéine. Les propriétés physicochimiques très intéressantes (lumière verte d'irradiation,T1/2 = 72 jours, photostable) de cette pince ont été évaluées.Parallèlement, une synthèse efficace et pratique pour générer directement la fonction hydroxyle en ortho de l'azobenzène dans des conditions douces a été développée. Nous avons synthétisé plusieurs séries en faisant varier les substituants enpositions para ou/et en ortho afin d'étudier l'influence de ces subsituants sur la régiosélectivité de cette ortho-hydroxylation. L'équation de Jaffé et ses extensions ont donné une relation linéaire avec d'excellents coefficients de détermination R2.Enfin, les azophenols ont été évalués comme des détecteurs colorimétriques d'anions. Leurs caractéristiques ainsi que le mécanisme d'interaction ont été déterminés par une inspection visuelle, des mesures UV-Visible et des expériences de RMN. / Abstract : A methodological study on the synthesis of tetrasubstituted azobenzenes has been realized. We concluded that synthesis of multisubstitued azobenzene is hardly affected by the steric hindrance in ortho position and the electronic effect of para substituents.A tetrachloro and a tetrafluoro azobenzene have been synthesized in good yields, via nitrosobenzene intermediate. The tetrafluoro derivative was then functionalized with an alkyne chain containing a maleimide group for bioconjugation to cysteine residue. Its interesting photoisomerisation properties (green light of irradiation,1/2 = 72 days, photostable) were evaluated.We also developed a practical and effective method for direct ortho-hydroxylation of azobenzenes under mild conditions. The reaction showed a very good functional groups tolerance, leading to a wide range of original azophenols in satisfying to high yields.Through Hammett-Jaffé analyses, we presented a study that correlated electronic and steric perturbations induced by substituents nature to the regioselectivity of this direct hydroxylation process.Azophenols were finally evaluated as anion sensors. Anion sensing characteristics as well as interaction mechnism were determined using visual inspection, UV-Vis and NMR spectrocopy.

Alkenes can undergo a variety of chemical reactions to form more complex molecules with a range of functional groups. This makes them useful starting materials for synthesizing a wide range of organic compounds. Chapter I provided an overview of the development history of alkenyl C−H bond activation. The early reactions of C−H compounds with metal complexes, as well as stoichiometric activation of the transition metal-activated C–H bond, were discussed. Then the first successful and efficient organometallic-catalyzed transformations of a C−H bond, the first transition metal-catalyzed vinylic C–H functionalization, and the first transition metal-catalyzed olefinic C–H functionalization under mild conditions were demonstrated. Finally, enantioselective vinylic C–H functionalization was discussed. In Chapter II, a method for enantioselective vinylic C(sp2)−H bond activation using a Ru(II) catalyst and a chiral transient directing group was developed. Chiral amine was also utilized to control the Z/E stereoselectivity. The method demonstrated a broad substrate scope with good yield, high Z/E ratio stereoselectivity, and excellent enantioselectivity. Its synthetic utility was demonstrated by the synthesis of key structural motifs of particularly useful natural products and pharmaceutical compounds. Additionally, a rare vinylic C−H bond activated ruthenic complex was isolated and determined by single-crystal X-ray diffraction. The methodology suggested in this work is expected to facilitate the further development of asymmetric vinylic C−H functionalization reactions. In Chapter III, a practical and efficient methodology for Ru(II)-catalyzed enantioselective alkenyl C–H bond functionalization of indole-substituted acrylaldehyde derivatives via the chiral transient directing group (CTDG) strategy to obtain optically active pyrrolo[1,2-a]indole derivatives was suggested. The methodology resulted in a series of optically active products with good yields (up to 80%), good stereoselectivity (up to 25.0:1 Z/E), and excellent enantioselectivity (up to 95% ee). Furthermore, synthetic transformations were explored. Chapter IV presented the first demonstration of a sequentially composed catalytic substitution reaction of alkenes for building multi-amido methylated derivatives while reserving the π- components. The process involved a simple Fe (III)-catalyst and bisamidomethane reagent, which directly and selectively transformed α-substituted styrenes into several biologically and pharmaceutically relevant N-heterocycles through tandem processes.

Previous work was successful at delineating reaction pathways for the photoactivated synthesis of an amine, [CztBu(PyriPr)(NH2−PyriPr)], by double intramolecular C−H activation and functionalization via irradiating a metal(II) azido complex, [CztBu(PyriPr)2NiN3. The present work seeks to expand upon earlier research, and to substitute the metal with iron or cobalt, and to expand the study to photocatalyzed intermolecular C−H activation and functionalization of organic substrates. Density functional theory (DFT) – B3LYP/6-31+G(d') and APFD/Def2TZVP – and time-dependent density functional theory (TDDFT) were used to propose a detailed pathway comprised of intermediates of low, intermediate, or high spin multiplicity and photo-generated excited states for the reaction of the azido complex, [CztBu(PyriPr)2MN3] to form the amine complex [CztBu(PyriPr)M(NH2−PyriPr)], M = Co, Ni or Fe, and the intermediates along the reaction pathway. For applications on quantum computing, the photophysical properties of photoactive d8 nickel(II) complexes are modeled. Such systems take advantage of a two-level system pathway between ground to excited state electronic transitions and could be useful for the discovery of successful candidates for a room temperature qubit, the analogue of a classical computational bit. A modified organometallic model, inspired by a nitrogen vacancy selective intersystem crossing model in diamond, was developed to take advantage of the formation of excited states. Tanabe-Sugano diagrams predict areas where these excited states may relax via phosphorescent emission. Under Zeeman splitting, these transitions create the conditions required for a two-level system needed to design a functional organometallic qubit.

The base-catalysed reaction of 4H-pyran-4-one with a range of nucleophiles, namely diethyl malonate, ethyl acetoacetate, nitromethane, acetylacetone and ethyl cyanoacetate, was developed as a reliable, high yielding method for the preparation of para-substituted phenols. The methodology was extended to include the use of the substituted pyranones, maltol, 2,6-dimethyl-4H-pyran-4-one and diethyl chelidonate. Reactions were studied using conventional heating methods and microwave irradiation. Microwave irradiation had definite beneficial effects, with improved yields, reduced reaction times and cleaner reaction profiles. The potential of this methodology was examined for the regioselective placement of ¹³C-atoms into benzene rings using ¹³C-labelled nucleophiles or ¹³C-labelled 4H-pyran-4-ones. [3,5-13C₂]4H-Pyran-4-one and [2,6-13C₂]4H-pyran-4-one were prepared from various ¹³C-labelled versions of triethyl orthoformate and acetone. This methodology was applied to the synthesis of [1,3,5-¹³C₃]gallic acid, via the base-catalysed reaction of [3,5-¹³C₂]4H-pyran-4-one with diethyl [2-¹³C]malonate, followed by subsequent transformations to yield [1,3,5-¹³C₃]gallic acid. The preparation of [2-¹³C]phloroglucinol was carried out via [2-¹³C]resorcinol, with regioselective placement of a single ¹³C-atom into the aromatic ring. This was accomplished from non-aromatic precursors, with the source of the ¹³C-atom being [¹³C]methyl iodide. The key step in this synthesis was the introduction of the third hydroxyl group, which was achieved using a modified iridium-catalysed C-H activation/borylation/oxidation procedure. The scope of an existing C-H activation/borylation reaction was modified and expanded to include a range of protected resorcinol derivatives. A catalyst system was developed which allowed high conversion to the intermediate arylboronic acids, followed by oxidation using aqueous Oxone® to yield the corresponding phenols. Finally, to demonstrate the potential of these new methods for application in the synthesis of isotopically labelled natural products and polyphenols, the syntheses of ¹³C-labelled anthocyanins were studied. A route was developed that could be applied to the synthesis of either cyanidin-3-glucoside or delphinidin-3-glucoside. Only the final coupling/cyclisation step to yield the desired anthocyanin targets remains to be carried out.