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Organoboron compounds are highly valued synthetic intermediates due to their diverse array of reactivity, which is often utilized in the synthesis of valuable organic molecules. For this reason, there is significant interest in the development of novel borylation protocols, especially those whose products are suitable for further synthetic transformations towards valuable classes of compounds. Research in organoboron synthesis has been geared heavily toward transition metal-catalyzed addition to double and triple bonds, though an increasing number of publications detail transition metal-free borylation techniques involving substrate-mediated activation of a diboron reagent. This dissertation describes the author's contributions to the development of both a transition metal-catalyzed diboration and a transition metal-free protoboration. A transition metal-free diboration of alkynamides is described in Chapter 1 which uses the unsymmetrical, differentially protected diboron reagent, pinBBdan. The method installs both boron moieties in a regio- and stereoselective fashion. The products have synthetic value because they are shown to have chemoselectivity in downstream cross-coupling reactions; chemoselectivity is made possible by to the significant difference in Lewis acidity of the pinacol and diaminonapthalene-protected boron centers. This method allows for facile synthesis of tetrasubstituted alkenes with a set geometry about the double bond. A protoboration of allenes employing a Cu(II) catalyst under aqueous and atmospheric conditions is described. Though Cu(I)-catalyzed allene protoboration is well-described in the literature, this is the first report of an analogous Cu(II)-mediated process. The selectivity of the reaction is ligand-controlled, and moderate to good regioselectivities and yields can be achieved through use of a triphenylphosphine as ligand. The method is an environmentally friendly and facile means by which to borylate a challenging cumulated substrate. / Ph. D. / Organoboron compounds are valuable because of their ability to undergo a wide variety of chemical transformations, and they are often used as intermediates in the synthesis of challenging target molecules. In order for this reactivity to be exploited, methods must exist for the efficient synthesis of the desired boron-containing compound. This dissertation describes the author’s contributions to the development of two new methods by which to synthesize organoboron products. The first method involves installation of two differently ligated boron moieties onto an alkynamide substrate to produce a single, uncommon trans isomer as product. A synthetic application of these diboration products is described. The second method involves installation of a single boron moiety into allenes. Though the same overall transformation has been achieved in the literature with use of highly air-sensitive catalysts and organic solvents, the described method entails use of air-stable CuSO4 as catalyst and water as solvent. Therefore, the method is operationally simple and environmentally friendly relative to previously described methods.

The effect of substituents on the stabilities of cumulenes-ketenes, allenes, diazomethanes and isocyanates and related systems-alkynes, nitriles and nitrile oxides is studied using the density functional theory (B3LYP, SVWN and BP86) and ab initio (HF, MP2) calculations at the 6-31G* basis set level. Using isodesmic reactions, correlation between stabilization energies of cumulenes and substituent group electronegativities (c BE) is established and the results from DFT and MP2 methods are compared with the earlier HF calculations. Calculations revealed that the density functional methods can be used to study the effect of substituents on the stabilities of cumulenes. It is observed that the cumulenes are stabilized by electropositive substituent groups from s -electron donation and p -electron withdrawal and are destabilized by electronegative substituent groups from n-p donation. The calculated geometries of the cumulenes are compared with the available experimental data.High level ab initio and density functional theory calculations have been used to study the energetics of low-barrier hydrogen bond (LBHB) systems. Using substituted formic acid-formate anion complexes as model LBHB systems, hydrogen bond strength is correlated to the pKa mismatch between the hydrogen bond donor and the hydrogen bond acceptor. LBHB model systems are characterized by the 1H-NMR chemical shift calculations. A linear correlation between the calculated hydrogen bond strength and the predicted 1H-NMR chemical shift was established. It is concluded that the pKa matching within the enzyme active site of the two species involved in the LBHB is important to maximizing catalytic stabilization.

This thesis has been focused on enzymatic kinetic resolutions and stereoselective oxidative transformations of enallenes catalyzed by PdII. In the first part of the thesis, a detailed discussion on Candida antarctica lipase B (CALB)-catalyzed kinetic resolution (KR) of δ-functionalized alkan-2-acetates is shown. We gained a deeper insight into the mechanism of enzyme-substrate recognition. Changing from an anhydrous solvent to water or a water-containing organic solvent enhanced the enantioselectivity. The effect of –OH was also confirmed by a lipase mutant suggesting that the water molecule mentioned above can be partly mimicked. In the second part of the thesis, we developed an efficient KR for allenic alcohols. On this basis, a novel synthesis of optically pure 2-substituted 2,3-dihydrofurans from allenic alcohols via a Ru-catalyzed cycloisomerization was reported. The developed protocol enabled us to assemble an optically pure precursor for total synthesis with three chiral centers from readily available allenol in 2 days. In the third part, we reported a class of reactions involving C–H cleavage under mild conditions: PdII-catalyzed oxidative transformations of enallenes. These reactions are particularly attractive since a number of meticulous structures have been achieved from readily accessible starting materials. The directing effect of an unsaturated hydrocarbon was found to be key for these transformations. In the final part, we developed the carbonylative insertion reaction discussed in the third part of the thesis into an asymmetric version. By using this methodology, a number of cyclopentenone compounds were obtained in good to excellent enantioselectivity.

This thesis describes the development and mechanistic studies of carbocyclization reactions of allene-substituted olefins and 1,3-dienes, catalyzed by palladium(0) and palladium(II). These reactions results in the formation of [n,3,0] bicyclic systems (n = 3-5) with high stereoselectivity and in good to excellent yields. The first carbocyclization presented is a novel palladium(0)-catalyzed cyclo- isomerization of allene-substituted olefins. Secondly an efficient aerobic biomimetic system has been developed for a Pd(II)-catalyzed allylic oxidative carbocyclization of allene-substituted olefins. Additionally, during the studies of palladium-catalyzed carbocyclizations of allene-substituted olefins, it was found that in the absence of palladium a mild thermal ene-reaction occurs. In this manner stereodefined, functionalized bicyclic compounds are obtained with good regioselectivity and in high yields. The third and fourth carbocyclization developed are a palladium(II)-catalyzed oxidation and a palladium(0)-catalyzed intramolecular telomerization of allene-substituted 1,3-dienes. A mechanistic study of the palladium(II)-catalyzed oxidation of allene-substituted 1,3-dienes was made, and reaction intermediates could be isolated. The stereochemistry of the reaction intermediates was assigned, and this made it possible to suggest a mechanism for the reaction. The presented mechanism is a trans carbopalladation of the 1,3-diene, where the allene act as the carbon nucleophile. Due to different stereochemical outcomes of the stoichiometric and catalytic reactions, this mechanism could only explain the stoichiometric reaction. Another mechanism for the catalytic reaction was suggested, which rationalizes both the regio- and stereochemistry of the products.

In recent years, the exploitation of flow technologies as an enabling tool to access unique chemical reactivity has flourished. This dissertation describes the utilisation of these flow methods to access new sets of highly versatile, unstable diazo compounds and their application in coupling reactions. In the first chapter, an introduction into the structure and reactivity of diazo compounds is provided, as well as a discussion of currently available methods for their generation. The second chapter describes the coupling of flow-generated, semi-stabilised diazo compounds with terminal alkynes for the synthesis of racemic di- and trisubstituted allenes, using copper(I) catalysis. The third chapter follows with an account of creating chiral disubstituted allenes by asymmetric coupling of flow-generated, semi-stabilised aryl aldehyde-derived diazo compounds with terminal alkynes, using a copper(I) catalyst and a newly developed pyridine(bisimidazoline) ligand. The fourth chapter describes the generation of new, highly reactive non-stabilised diazo compounds and their reaction with arylboronic acids to allow metal-free ‘protodeboronative’ and ‘oxidative’ C(sp2)-C(sp3) cross-couplings. Finally, the fifth chapter describes the experimental procedures relevant for the results described in Chapters 2-4.

Depuis une trentaine d'année, l'obtention de composés chiraux énantiopurs tient un rôle prépondérant dans la synthèse de molécules biologiquement actives, tout particulièrement dans les domaines de la pharmacie de l'agrochimie et de la parfumerie. Cet engouement pour la synthèse énantiosélective a conduit à la mise au point de multiples ligands chiraux et notamment les diphosphines chirales par atropoisomérie initiées par les travaux de Noyori et Takaya. Nous nous sommes intéressés à la synthèse de nouveaux ligands hétérocycliques bidents et chiraux par atropoisomérie par des voies de synthèse originale où une double construction des hétérocycles sera mise en œuvre dans l'étape clé. En parallèle, nous avons aussi développé une approche de synthèse permettant l'obtention de mono et bis phosphonates atropochiraux utilisant des allènes comme précurseurs de la synthèse. / Atropisomeric diphosphine ligands play a crucial role in the synthesis of enantiopur molecules, particularly in pharmaceutical, agrochemical and flavors industries. Growing demand in asymmetric synthesis, impose to develop news ligands by rapid, economic and effective strategies of synthesis. This optically pure ligand was combined with multiples transition metal to form catalyst what will have used wide variety of entioselective reaction type.Over the past few years, a new family of ligands has emerged, possessing biheterocyclic skeleton and thus allowing the introduction of different steric and electronic interactions. We will report a efficient syntheses of the new atropisomeric five-membered heterocyclic diphosphines with original strategy of synthesis whose the main stages consist in a double heterocyclic construction. In the second part, we will develop an approach permitting to obtain atropochiral phosphonates with a similar strategy of synthesis from allenylphosphine oxides or allenylphosphonates as precursors.

Ce travail de thèse décrit la synthèse de nouveaux ligands chiraux pour des applications en catalyse asymétrique. Nous avons ainsi synthétisé différents allènes chiraux possédant des groupements phosphines et nous les avons testés sur des métaux de transition comme l'or(I). Les allènes possédant des oxydes de phosphine ont été préparés à partir de précurseurs de l'acétate propargylique correspondant avec des rendements modérés à élevés. Nous avons pu montrer que les allènes possédant un motif pyridine se coordinent efficacement avec de l'or(I), donnant deux nouveaux types de complexes d'or vinylique. Un complexe cationique vinylique avec un fragment triphénylphosphine d’or(I) permet de préparer des dérivés fonctionnalisés tels qu’un sel d'indolizinium et un iodure de vinyle. L’autre complexe contenant le groupement de chlore d’or a été utilisé comme catalyseur dans des réactions de cyclisation catalysées par de l'or. De plus, les différents allènes synthétisés ont été étudiés dans le cadre de réarrangements catalysés par l'or. Les allènes avec les groupements 3,5-methoxyphenyl et vinylallène peuvent conduire respectivement à des produits indényle et cyclopentadiényle, portant tous deux un centre stéréogène. En outre, un transfert complet de chiralité axiale en chiralité centrée a été observé sur le produit d’indényle -oxyde de phosphine à partir de l’allène optiquement pur. L’étape suivante, nous avons préparé quelques nouveaux précatalyseurs alléniques bisphosphine bimétalliques à base d’or. Ces nouveaux complexes peuvent être utilisés dans des réactions intermoléculaires et des réactions de cyclisation catalysées à l’or. Plusieurs produits carbocycliques et hétéocycliques ont été obtenus avec des rendements modérées à excellents. Ces complexes d’or chiraux peuvent être séparés par HPLC chirale préparative. Certains des excès énantiomériques obtenus dans les réactions des cycloisomérisations sont prometteurs. / This thesis has focused on the synthesis of new ligands bearing chirality for asymmetric catalysis. We first aimed to synthesize chiral allenes with phosphine moieties and use them as ligands of transition metals such as gold(I) species. Allenes bearing a phosphine oxide group were prepared from the corresponding propargylic acetate precursors in moderate to high yields. When substituted by a pyridine substituent, these substrates efficiently combined with gold(I) species to afford two types of new vinyl gold complexes. One cationic vinyl complex featuring a triphenylphosphine gold(I) moiety can be further functionalized to give an indolizinium salt and a vinyliodide derivative. The other one bearing a chlorogold(I) group can be used as a catalyst in gold-catalyzed cyclization. Moreover, other allenes have been investigated in gold(I)-catalyzed rearrangements. To our delight, the allenes featuring a 3,5-methoxyphenyl substituent and a vinylallene can produce respectively indenyl and cyclopentadienyl phosphine oxide products bearing stereogenic centers. In addition, a complete axial-to-center chirality transfer was observed on the indenylphosphine oxide product starting from the optically pure allene. In a next attempt, we have prepared some new digold-allenyl bisphosphine precatalysts. These new complexes can be used in gold-catalyzed intermolecular reactions and cyclization reactions. Several carbo- and heterocyclic products were produced in moderate to excellent yields. These chiral gold complexes could be separated by preparative chiral HPLC. Some promising enantiomeric excesses were observed in cycloisomerization reactions.

Les allènes ont longtemps été perçus comme des curiosités scientifiques notamment à cause de leur réactivité et de leur structure très particulières. Cependant ils bénéficient d'une attention de plus en plus importante de la part des chercheurs depuis plusieurs décennies grâce au développement de méthodes efficaces pour les synthétiser. Au cours de cette thèse, nous nous sommes intéressés à l'hydrofonctionnalisation intermoléculaire de ces molécules insaturées. Les hydrofonctionnalisations sont généralement des réactions très efficaces, qui permettent d'éviter la production de déchets, et qui donnent accès à un très large panel de produits d'intérêts. Jusqu'à maintenant, les réactions d'hydrofonctionnalisations d'allènes ont nécessité l'emploi de systèmes catalytiques faisant appel à des métaux précieux combinés à des ligands complexes. Notre objectif était de rendre ces réactions réalisables avec le système le plus simple possible et un catalyseur peu onéreux et peu toxique : le cuivre. Nous avons tout d'abord étudié les réactions d'hydroaminations, qui ont été réalisées avec de nombreux allènes variés. Par la suite, nous avons souhaité démontrer le potentiel de notre système catalytique, en étendant cette réactivité pour la création de liaisons C-C et C-O. / Allenes were perceived as scientific oddity for a long time, due to their particular reactivity. But they are currently attracting a growing interets of chemists since the discovery of efficient synthesis for these compounds in the past few decades. During this thesis, we focused on intermolecular hydrofunctionalization of these substrates. Hydrofunctionalization process generally avoid the production of any wastes, and give an efficient access to a large scope of valuables compounds. Until now, allenes hydrofunctionalizations required the use of catalytic systems using precious metals combined with complex ligands. Our goal was to perform this sort of reaction with a simplest possible system using a cheap metal with low-toxicity : copper. We started studying hydroaminations process, which were realized on a large scope of allenes. Subsequently, we wanted to demonstrate the potential of our new catalytic system and so applied it for the creation of C-C and C-O bonds.

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