Cette thèse décrit le développement de trois méthodes de formation de liaison C-P par fonctionnalisation de liaison C-H avec l’utilisation d’aucun métal de transition.Tout d’abord, une méthode de phosphorylation régiosélective a été développée via un procédé séquentiel, constitué d’une activation de la pyridine par l’acide de Lewis BF3 suivie d’une oxydation par la chloranile qui réaromatise le cycle pyridinique. La caractérisation de l’intermédiaire de Meisenheimer par des études RMN à basse température nous a permis de confirmer le mécanisme de la réaction. Ensuite, nous avons développé une voie d’accès directe aux oxydes de benzo[b]phosphole à partir d’oxyde de phosphine secondaire et d’alycne via l’utilisation d’un oxydant organique et d’un organophotocatalyseur. Mis à part la grande étendue de cette méthodologie que nous avons appliquée à de nombreux susbtrats, nous avons effectué de nombreuses études physico-chimiques (RPE, RMN, diffraction des rayons X,…), qui nous a permis de proposer un courant. Ces études nous ont notamment permis de caractériser un complexe à transfert de charge existant entre l’état fondamental de l’organophotocatalyseur et l’oxydant organique qui est à l’origine de l’efficience de ce procédé. Enfin, nous avons développé une méthode de phosphorylation régiosélective et photoinduite d’aniline, ne nécessitant l’ajout d’aucun photocatalyseur. La réaction fonctionnne grâce à la photoexcitation d’un complexe à transfert de charge l’aniline et l’oxydant organique. Des études mécanistiques ont permis de caractériser ce complexe ainsi qu’un intermédiaire de type iminium. / This thesis describes the successful development of three modes of activation for the formation of Carbon–Phosphorus bonds under mild conditions and without the use of transition metals.First, a regioselective phosphorylation of pyridines has been developed via a sequential process consisting of the activation of the pyridine with a Lewis acid (BF3) followed by oxidative aromatization mediated by chloranil. The characterization of the Meisenheimer complex enabled to confirm the proposed reaction mechanism. Next, we developed a straightforward approach for the synthesis of benzo[b]phospholes from the reaction of secondary phosphine oxides and alkynes in the presence of an organic oxidant and eosin Y as a catalyst. Apart from the broad scope of this reaction, extensive mechanistic investigations, including EPR, NMR, steady state photolysis permitted the elucidation of the mechanism of this photoreaction. It has been suggested that the oxidant and the photocatalyst come together to form a ground state charge transfer complex that is the driving force of the photocatalyzed process. Finally, we developed a metal-free photoinduced approach for the phosphorylation of anilines and related structures. The reaction proceeded through the formation of an electron donor acceptor complexes between anilines derivatives (electron donors) and N–ethoxypyridinium (electron acceptor). Scope and limitations of this process are discussed along with detailed mechanistic studies.

Les composés marqués aux isotopes de l’hydrogène possèdent des nombreuses applications lors des phases précliniques de développement des médicaments. Par exemple, les composés deutérés sont utilisés comme étalons internes dans la quantification par LC-MS de métabolites alors que les molécules tritiées sont souvent des radiotraceurs de choix dans les études d’absorption, distribution, métabolisme et excrétion (ADME) moléculaire des candidats médicaments. Après une brève introduction, un premier chapitre discutera du développement d’une méthode douce et sélective, catalysée par des nanoparticules de ruthénium, qui permet d’effectuer le marquage en une étape de bases azotées et de médicaments dérivés. En changeant le ligand qui stabilise le nanocatalyseur, on a réalisé des échanges isotopiques compliqués tels que des tritiations en utilisant une pression sous-atmosphérique de tritium gaz et des deutérations d’oligonucleotides sensibles. Le chapitre suivant décrira la modification des catalyseurs commerciaux à base de ruthénium grâce à la coordination de carbènes N-hétérocycliques (NHCs). La modification assure une régio- et une chimiosélectivité améliorées lors de la deutération d’alcools aliphatiques. Certains des catalyseurs modifiés ont permis l’échange hydrogène/deutérium sur des molécules, particulièrement sensibles à la réduction, qui n’ont pas pu être isolées en utilisant le catalyseur commercial. Dans le dernier chapitre, la synthèse et l’évaluation de l’activité catalytique des nanoparticules à base d’iridium seront discutées. Ces nanocatalyseurs ont démontré une réactivité intéressante dans le marquage des composés complexes. Dans certains cas, les nanoparticules d’iridium ont permis l’incorporation de deutérium sur des positions inhabituelles en comparaison avec d’autres réactions d’échange isotopique déjà décrites. / Hydrogen isotopes labelled compounds possess a broad range of application in the early pre-clinical phases of drug development process. For instance, deuterated compounds are applied as internal standard in quantitative LC-MS techniques while tritiated molecules are often the preferred radioactive tracers for the study of molecular absorption, distribution, metabolism and excretion (ADME). After a brief introduction, a first chapter will discuss the development of a mild and selective method to perform late stage labelling of variously functionalized nucleobases and drug analogues catalyzed by ruthenium nanoparticles. By changing the ligand which stabilizes the nanocatalyst, we achieved challenging isotopic exchanges such as tritiations of pharmaceuticals using subatmospheric pressure of tritium gas and deuteration of sensible oligonucleotides. The next chapter will describe the modification of commercially available ruthenium nanocatalysts via the coordination of N-Heterocyclic carbenes (NHCs). The modification granted enhanced regio and chemoselectivity for the deuteration of aliphatic alcohols. Some of the modified ruthenium catalysts allowed the hydrogen/deuterium exchange on easily reducible compounds which were not obtainable using the unmodified commercial catalyst. The final chapter will discuss the synthesis and the evaluation of the catalytic activity of iridium nanoparticles. The latter, showed an interesting reactivity for the labelling of challenging substrates. In some of the investigated compounds, IrNps were able to introduce deuterium with unusual regioselectivities compared to already described hydrogen isotope exchange reactions.

No description available.

In an effort to obtain more efficient and greener chemical transformations, a substantial amount of research interest has been directed towards the use of arene C-H bonds as functional groups. Hydroarylation of alkynes through direct functionalisation of C-H bonds has been studied in recent years leading to the development of high-yielding metal-mediated processes. The main aim of the current work is the addition of a third component in the hydroarylation of alkynes trough C-H activation, in order to achieve a second C-C bond formation. Attempts at palladium-catalysed three-component reaction of unactivated indoles with alkynes and aryliodides are described. The three-component reaction was studied in the intermolecular mode with both aryliodides and the more reactive diaryliodonium salts. These latter regents are reactive arylating and oxidising agents and have been used in the direct arylation of indoles under mild conditions through a PdII-PdIV catalytic cycle. In both cases the three-component product was not obtained. The intramolecular version of the reaction using alkyne-tethered indoles and diaryliodonium salts is also described. In this case the tandem process was successful, especially when using ethynylbenzyl indole derivatives, the Z-tetrasubstituted olefins could be selectively obtained under mild conditions. Finally, a low-yielding synthesis of chromenes from propargylaryl ethers and diaryliodonium salts is also discussed.

This thesis concerned about the Ru-catalyzed C-H functionalizations on the synthesis of 2-arylindole unit, silylation of heteroarenes and preparation of aryne precursor. In the first project, we developed the Ru-catalyzed C2-H arylation of N-(2-pyrimidyl) indoles and pyrroles with nucleophilic arylboronic acids under oxidative conditions. Wide variety of arylboronic acids afforded the desired product in excellent yield regardless of the substituents or functional group electronic nature. Electron-rich heteroarenes are well suited for this method than electron-poor heteroarenes. Halides such as bromide and iodide also survived, further derivatisation of the halide is shown by Heck alkenylation. In order to find catalytic on-cycle intermediate extensive mechanistic experiments have been carried out by preparing presumed ruthenacyclic complexes and C-H/D exchange reactions. It suggested that para-cymene ligand is not present in the catalytic on-cycle intermediate and we suspect that metalation occurs with electrophilic ruthenium center via SEAr mechanism. In the second project, we developed the Ru-catalyzed silylation of gramine, tryptamine and their congeners using silanes as coupling partner. The transformation worked well with many different silanes. Regarding directing group, nitrogen atom containing directing groups are more favoured than the oxygen containing directing groups. Wide range of gramines and tryptamines also yielded the desired product in poor to excellent yield. At higher temperature, albeit in low yield, undirected silylation occurred. In order to get some insights about the reaction pathway of the silylation C-H/D exchange experiments were performed, and it revealed the possibility of C4-H activation of gramines by an electron rich metal- Si-H/D experiments showed Si-H activation by Ru is easy. In the final project, we presented the closely related aryne precursors from arylboronic acids via Ru-catalyzed C-H silylation of arylboronates and their selective oxidation. Worthy of note, the aryne capture products obtained from arylboronic acids in a single purification.

This thesis comprises three projects on the theme of catalytic C(sp3)–H carbonylation of secondary aliphatic amines. Chapter 2 describes the development of a general methyl C–H carbonylation of secondary aliphatic amines to form synthetically useful β-lactam building blocks. Amines exhibiting a range of substitution patterns around the nitrogen functionality, and bearing a wide variety of functional groups, could be tolerated in the reaction. The desired β-lactam products were delivered in high yields, with excellent selectivity observed for the β-C–H position. Computational studies suggested that the reaction proceeds through a novel carbamoyl cyclopalladation pathway, which is distinct from classical cyclopalladation. The subsequent discovery of a selective methylene C–H carbonylation of α-tertiary amines (ATAs) is discussed in chapter 3. By employing the ATA motif, remarkable levels of selectivity for β-methlyene C–H bonds were achieved, even in the presence of traditionally more reactive methyl C–H and C(sp2)–H bonds. Once more, the reaction was found to exhibit excellent functional group tolerance, delivering highly functionalised β-lactam building blocks in high yields and selectivity. Chapter 4 presents work towards the total synthesis of the marine natural product (±)cylindricine C. The key step of this synthesis was demonstrated to proceed in good yield and excellent selectivity.

Lolines are specialized metabolites produced by endophytic fungi, such as Neotyphodium and Epichloë species, that are in symbiotic relationships with cool-season grasses. Lolines are vital for the survival of the grasses because their insecticidal and antifeedant properties protect the plant from insect herbivory. Although lolines have various bioactivities, they do not have any concomitant antimammalian activities. Lolines have complex structures that are unique among naturally occurring pyrrolizidine alkaloids. Lolines have four contiguous stereocenters, and they contain an ether bridge connecting C(2) and C(7) of the pyrrolizidine ring. An ether bridge connecting bridgehead C atoms is unusual in natural products and leads to interesting questions about the biosynthesis of lolines in fungal endophytes. Dr. Pan, who was a graduate student in Dr. Schardl Lab at University of Kentucky, isolated a novel metabolite, 1-exo-acetamidopyrrolizidine (AcAP). She observed that AcAP was accumulating in naturally occurring and artificial lolO mutants. I synthesized an authentic sample of (±)-AcAP and compared it spectroscopically with AcAP isolated from a lolO mutant to determine the structure and stereochemistry of the natural product. I was also able to grow crystals of synthetic (±)-AcAP, X-ray analysis of which further supported our structure assignment. There were two possible explanations for the fact that a missing or nonfunctional LolO led to the accumulation of AcAP: that AcAP was the actual substrate of LolO, or that it was a shunt product derived from the real substrate of LolO, 1-exo-aminopyrrolizidine (AP), and that was produced only when LolO was not available to oxidize AP. To distinguish between the two hypotheses, I synthesized 2´,2´,2´,3-[2H4]-AcAP. Dr. Pan used this material to confirm that AcAP was an intermediate in loline alkaloid biosynthesis, not a shunt product. To determine the product of LolO acting on AcAP, Dr. Pan expressed LolO in yeast (Saccharomyces cerevisiae). When Dr. Pan fed AcAP (synthesized by me) to the modified organism, it produced NANL, suggesting that LolO catalyzed two C–H activations of AcAP and the formation of both C–O bonds of the ether bridge in NANL, a highly unusual transformation. Dr. Chang then cloned, expressed, and purified LolO and incubated it with (±)-AcAP, 2-oxoglutarate, and O2. He observed the production of NANL, further confirming the function of LolO. Dr. Chang also observed an intermediate, which we tentatively identified as 2-hydroxy-AcAP. In order to determine whether the initial hydroxylation of AcAP catalyzed by LolO occurred at C(2) or C(7), I prepared (±)-7,7-[2H2]- and (±)-2,2,8-[2H3]-AcAP. When Dr. Pan measured the rate of LolO-catalyzed hydroxylation of these substrates under conditions under which only one C–H activation would occur, she observed a very large kinetic isotope effect when C(2) was deuterated, but not when C(7) was deuterated, establishing that the initial hydroxylation of AcAP occurred at the C(2) position. In order to determine the stereochemical course of C–H bond oxidation by LolO at C(2) and C(7) of AcAP, I synthesized trans- and cis-3-[2H]-Pro and (2S,3R)-3-[2H]- and (2S,3S)-2,3-[2H2]-Asp. Feeding experiments with these substrates carried out by both Dr. Pan (Pro) and me (Asp) showed that at both the C(2) and C(7) positions of AcAP, LolO abstracted the endo H atoms during ether bridge formation. In summary, feeding experiments with deuterated (±)-AcAP derivatives and its amino acid precursors have shown that AcAP is an intermediate in loline biosynthesis. We have shown that LolO catalyzes the four-electron oxidation of AcAP at the endo C(2) position first and then the endo C(7) position to give NANL.

Density Functional Theory (DFT) is a powerful tool for treating large organometallic structures efficiently and accurately. DFT calculations on the Hg-catalyzed oxidation of methane to methyl bisulfate in sulfuric acid suggest the lowest energy pathway involves a closed-shell electrophilic C–H activation mechanism coupled with metal alkyl reductive functionalization and oxidation by SO3. Comparison to Tl, Zn, and Cd suggests that Hg is unique in its ability to catalyze this set of reaction steps. Comparison to K2S2O8 highlights the selectivity of this C–H activation reaction as opposed to radical conditions. In contrast, DFT calculations indicate that CoIII(TFA)3 oxidizes methane through a radical TFA ligand decarboxylation pathway. A similar decarboxylation pathway is identified for MnIII(TFA)3, but the low spin ground state of TlIII(TFA)3 favors electrophilic C–H activation over this decarboxylation pathway. DFT calculations indicate that Cp(PPh2Me)Co=CF2 undergoes [2 + 2] cycloaddition with TFE by a unique open-shell singlet diradical mechanism. The significant stability of the perfluorometallacyclobutane reveals why catalytic metathesis with TFE is difficult.

Reactions of Fullerene with Tris(diphenylacetylene)(carbonyl)Tungsten and structure identified of these compounds. Due to its have many special mechanism for Tris(diphenylacetylene)(carbonyl)Tungsten. They could form interested structure of new compounds. Synthesis in high temperature we could get metallofullerene compounds W(CO)(£b2-C60)(£b2-PhC¡ÝCPh)(£b4-C4Ph4) 1a and W(CO)(£b2-C60)(¡ÝCPh)(£b5-C5Ph5) 1b. We also through C-H activation to get compound W(CO)2(£b3,£b5-C5Ph4(o-C6H4)CHPh) 2. To separate and Purify these compounds. To make sure mechanism of compound 2, we use cross experiment to confirm it.

No description available.