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Morita Baylis-Hillman (MBH) reaction a carbon-carbon bond forming reaction between an α,β-unsaturated carbonyl and aldehydes or activated ketones in the presence of a nucleophilic catalyst. The MBH reaction is an atom-economical method of rapid increase of molecular complexity. The development of this process has received considerable attention in recent years. This dissertation presents the development of a new catalytic system for the symmetric and asymmetric MBH reaction. The new system for the racemic version of this reaction was accomplished employing a 1:1:1 ratio of catalytic amounts (10 mol%) of MgI2, TMEDA and DMAP and proved to be highly effective. For the asymmetric version was developed a highly enantio-selective system based on Fu’s planar chiral DMAP derivative (II) with ee´s up to 98%. Abnormal MBH adducts are obtained employing either ethyl 2,3-butadienoate or ethyl propiolate in good yields, in the presence if MgI2 and either a tertiary amine or phosphine as the nucleophile. The α,β-unsaturated carbonyls where prepared by a modified direct α- methylenation using paraformaldehyde, diisopropylammonium trifluoroacetate, and catalytic acid or base with excellent yields for several carbonyls compounds. The Negishi cross-coupling reaction is the Pd or Ni-catalyzed stereoselective cross-coupling or organozincs and aryl-, alkenyl-, or alkynyl halides. Enantioselective Negishi cross-coupling of aryl zincs and α-bromo ketones was accomplished employing a NCN Pincer complex as the catalyst with ee´s up 99%. The required pincer complexes have been prepared by the oxidative addition of pincer ligands with palladium or nickel. Additionally, It has been developed a direct and highly active, (NCN)-Pd catalytic system for the α-arylation of ketones with a variety of aryl bromides using the air and moisture stable [t-BuPheBox-Me2]PdBr (XVI) as the catalyst. The adducts are obtained in excellent yields (92% average for 20 examples) in only 1 hour using 1 mol% of catalyst loading. Perhaps more importantly, the work described here shows that XVI is highly reactive, highly selective, even on substrates bearing challenging functional groups such alkenes.

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Introdução: As alterações anatômicas do fêmur proximal ou do acetábulo, como as decorrentes das sequelas da epifisiólise do fêmur proximal, da displasia do quadril da doença de Legg-Perthes-Calvé, podem levar ao desenvolvimento da artrose do quadril. No entanto, em torno de 80% dos indivíduos que desenvolvem essa doença têm uma anatomia óssea considerada normal. Ainda assim, surgiu a hipótese que alterações sutis do fêmur proximal ou do acetábulo, denominadas, respectivamente, cam e pincer, poderiam gerar um contato anormal entre essas estruturas ósseas, desencadear lesão condral e, como consequência, a artrose do quadril. Esse mecanismo foi denominado impacto fêmoro-acetabular. No entanto, a comprovação da relação entre o impacto e a artrose do quadril depende da uniformização dos critérios diagnósticos do cam e do pincer, ainda escassa e variável na literatura. Dessa forma, será possível a definição da prevalência e história natura do impacto fêmoro-acetabular e da sua relação com a artrose do quadril. Objetivo: Avaliar a prevalência do impacto fêmoro-acetabular tipo cam e tipo pincer em uma amostra de indivíduos assintomáticos. Pacientes e Métodos: Foram estudados 106 indivíduos assintomáticos (65 homens e 41 mulheres), com idade entre 20 e 40 anos. A condição determinante para a inclusão no estudo foi à ausência de história de dor no quadril ao longo da vida. Foram obtidas radiografias em ântero-posterior e Dünn 45°. A presença de cam foi determinada por um ângulo alfa, arbitrado, de 55° e a presença de pincer, quando observado o sinal da parede posterior e/ou o sinal de crossover. Resultados: Foi observada prevalência de cam de 29%; o sinal do crossover e da parede posterior ocorreram, respectivamente, em 20% e 29% dos indivíduos estudados. Pelo menos uma das imagens de impacto fêmoro-acetabular estava presente em 65% dos indivíduos da amostra. Conclusão: A prevalência encontrada das imagens de impacto fêmoro-acetabular (65%) está acima daquelas relatadas na literatura. É necessária a ampliação do estudo para confirmar os resultados encontrados e a realização de estudos prospectivos bem controlados para avaliar o papel do cam e do pincer no desenvolvimento da artrose do quadril. / Background: Anatomical abnormalities of the proximal femur or the acetabulum, such as those resulting from the consequences of slipped epiphyses of the proximal femur, the hip dysplasia of Legg-Calve-Perthes disease, could lead to the development of hip osteoarthrosis. Nevertheless, around 80% of individuals who develop this condition have a bone anatomy considered normal. Still, the hypothesis arose that subtle alterations of the proximal femur or the acetabulum, called, respectively, cam and pincer, could generate an abnormal contact between these bony structures, triggering chondral lesion and as a consequence, arthritis of the hip. This mechanism has been named femoroacetabular impingement. Nevertheless, evidence of the relationship between the impact and osteoarthritis of the hip depends on the standardization of diagnostic criteria of cam and pincer, still scarce and variable in the literature. Thus it will be possible to define the prevalence and natural history of femoroacetabular impingement and its relationship with hip osteoarthrosis. Aim: To determine the prevalence of cam-type and pincer-type femoroacetabular impingements in asymptomatic subjects. Patients and Methods: Were studied 106 asymptomatic subjects (65 males and 41 females) aged between 20 and 40 years. The determining condition for inclusion in the study was the absence of history of hip pain throughout life. Radiographs were obtained in anteroposterior pelvic view and Dunn 45° view. The presence of cam was determined by an angle alpha, arbitrated, 55 ° and the presence of pincer when the observed the posterior wall and / or crossover signs. Results: A prevalence of 29% of cam, and 20% and 29% of crossover sign and posterior wall sign respectively was found. At least, one of those radiographic signs of femoroacetabular impingement was found in 65% (68) of the cases. Conclusion: In conclusion, the prevalence of images of femoroacetabular impingement (65%) is above those reported in the literature. Increase of the study is necessary to verify the results found, and the performance of well-controlled prospective studies to evaluate the role of the cam and pincer in the development of osteoarthritis of the hip.

Ce travail de thèse présente la synthèse, la caractérisation et la réactivité de métallylènes stabilisés par différents ligands pinces fonctionnalisés par des substituants soufrés à différents états d'oxydation. Les métallylènes, analogues lourds des carbènes, présentent dans leur état fondamental singulet une paire d'électrons et une orbitale p vacante. Ces caractéristiques donnent à ces espèces un comportement et une réactivité particulière. La littérature décrit de nombreux exemples de métallylène stabilisés par différents types de ligands, parmi lesquels les ligands de type pince gagnent actuellement en importance. Dans la chimie des complexes de métaux de transition, il a déjà été démontré que les ligands de type pince constituent un type de plateforme efficace grâce aux possibilités de modulation des propriétés des complexes liées à la modulation du squelette du ligand. Au cours des dernières décennies, ces ligands se sont révélés efficaces pour la stabilisation de métallylènes stables. Cependant, un seul exemple de métallylène stabilisé par un ligand de type pince contenant du soufre a été reporté dans la littérature. Au cours de cette étude, des ligands pinces O,C,O chélatants contenant des groupement sulfonyles et sulfinyles ont été conçus, synthétisés et complètement caractérise par les méthodes physico-chimiques et computationnelle et leurs effets sur la stabilisation des métallylènes ont été étudiés. Dans un premier temps, un ligand pince de type bis-sulfone a été obtenu et étudié pour la synthèse de nouveaux métallylènes. A partir de ce ligand, un germylène et un stannylène ont été caractérisés, le germylène étant le premier exemple dans la littérature d'une espèce de germanium divalente stabilisée par un ligand pince de donneur d'oxygène. La réactivité des métallylènes a été testée pour obtenir des produits de cycloaddition avec l'ortho-benzoquinone et des complexes des métaux de transition (fer et tungstène). Il a été démontré que la bis-sulfone se comporte comme un ligand ajustable de type pince O,C,O-chélatant, la coordination pouvant être possible par l'un ou l'autre des atomes d'oxygène des groupements sulfonyles. [...] / This work presents the synthesis, characterization and reactivity of metallylenes stabilized by different functionalized pincer ligands with substituents containing sulfur atoms in different oxidation states. Metallylenes, the heavier analogues of carbenes, have in their singlet ground state a lone pair of electron and a vacant p orbital. These features give the particular behavior and reactivity of these species. The literature describes many examples of metallylenes stabilized by different types of ligands, among which lately the pincer type ligands are gaining importance. In the chemistry of transitional metal complexes it was shown for a long time that the pincer-type ligands are a versatile ligand platform thanks to the possibilities of modulating the properties of the complexes through small changes of the ligand backbone. In the last few decades these ligands proved to be effective for obtaining stable metallylenes. However, in the literature there is one sole example of metallylene stabilized through sulfur containing pincer-type ligands. For this study, para substituted sulfonyl and sulfinyl containing O,C,O-chelating pincer ligands were designed, synthesized and completely characterized by the physico-chemical and computational methods and their effects on the stabilization of metallylenes was investigated. First, a bis-sulfone pincer ligand was obtained and studied for the synthesis of novel metallylenes. With this ligand a germylene and stannylene were obtained and characterized, the germylene being the first example in the literature of a divalent germanium species stabilized by an oxygen donor pincer ligand. The reactivity of the metallylenes was tested for obtaining cycloadducts with ortho-benzoquinone and transition metal complexes (iron and tungsten). It was shown that the bis-sulfone behaves as an adjustable O,C,O-chelating pincer type ligand, the coordination could be possible with either one of the oxygen atoms of the sulfonyl groups. [...]

Polybutadiene, the homopolymer of 1,3-butadiene, is a synthetic rubber especially important in the production of tires. Industrially, it is polymerized using multi-site catalysts that do not offer significant control over molecular weight distribution resulting in polymers with poor mechanical properties. Single-site polymerization of 1,3-butadiene results in narrow molecular weight distribution and thus increased impact resistance and durability. Complexes of chromium and neodymium bearing bis-phosphinimine pincer ligands have been synthesized and studied for their behavior in 1,3-butadiene polymerization in combination with methylaluminoxane. The complexes that were active produced highly cis-1,4-polybutadiene with high molecular weight and narrow polydispersities. The co-polymerization of acrylonitrile and 1,3-butadiene with the bis-phosphinimine chromium (III) complexes and methylaluminoxane to produce nitrile-butadiene rubber was also explored. The insertion of 1,3-butadiene into nickel-methyl and nickel-hydride complexes bearing the bis-phosphinimine pincer ligands was examined using nuclear magnetic resonance spectroscopy and will also be discussed.

Polybutadiene, the homopolymer of 1,3-butadiene, is a synthetic rubber especially important in the production of tires. Industrially, it is polymerized using multi-site catalysts that do not offer significant control over molecular weight distribution resulting in polymers with poor mechanical properties. Single-site polymerization of 1,3-butadiene results in narrow molecular weight distribution and thus increased impact resistance and durability. Complexes of chromium and neodymium bearing bis-phosphinimine pincer ligands have been synthesized and studied for their behavior in 1,3-butadiene polymerization in combination with methylaluminoxane. The complexes that were active produced highly cis-1,4-polybutadiene with high molecular weight and narrow polydispersities. The co-polymerization of acrylonitrile and 1,3-butadiene with the bis-phosphinimine chromium (III) complexes and methylaluminoxane to produce nitrile-butadiene rubber was also explored. The insertion of 1,3-butadiene into nickel-methyl and nickel-hydride complexes bearing the bis-phosphinimine pincer ligands was examined using nuclear magnetic resonance spectroscopy and will also be discussed.

In this dissertation, catalytic C-F bond activation mediated by alumenium and silylium species, improved methods for the synthesis of highly chlorinated carboranes and dodecaborates, new type of P2Si= pincer silylene Pt complexes and PBP pincer Rh complexes are presented. In Chapter II, the design and synthesis of P2Si= and PBP ligand precursors is described. BrC6H4PR2 is shown to be a useful building block for PXP type of ligands with o-arylene backbone. RLi reagents displayed high chemoselectivity towards electrophiles, such as Si(OEt)4 and BX3 (X = Hal). In Chapter III, new chlorination methods to synthesize [HCB11Cl11]- and [B12Cl12]2- are presented. [HCB11Cl11]- was obtained via reactions of Cs[HCB11H11] with SbCl5 or via reactions of Cs[HCB11H11] with Cl2 in acetic acid and triflic acid. Heating Cs2[B12H12] in mixtures of SO2Cl2 and MeCN led to the isolation of Cs2[B12Cl12] in high yield. In Chapter IV, Et2Al[HCB11H5Br6] or Ph3C[HCB11H5Br6] were shown to be robust catalysts for sp3 C-F bond activation with trialkylaluminum as the stoichiometric reagent. Trialkylaluminum compounds were also shown to be able to be used as “clean-up” reagent for the C-F bond activation reactions, which led to ultra high TON for the catalytic reactions. In Chapter V, a series of (TPB)M complexes (M = Ni, Pd, Pt) were synthesized and characterized by multinuclear NMR spectroscopy and X-ray crystallography. The resulting metal complexes displayed strong dative M→B interaction and unusual tetrahedral geometry for four-coordinate 16ē species, due to the cage structure of the ligand. In Chapter VI, (PSiHP)PtCl was synthesized via the reaction of the ligand precursor and Pt(COD)Cl2, which was used to obtain a series of (PSiHP)PtX complexes(X= I, OTf, Me, Ph, Mes). After hydride abstraction by Ph3C[HCB11Cl11], the X ligand (X= I, OTf, Me, Ph) migrated from the Pt center to silicon center to give a cationic pincer silyl species. The migration was not observed when mesityl was used as the X ligand, which resulted in the first known pincer complex with central silylene donor. Our approaches towards PNP pincer boryl Rh complexes were summarized in Chapter VII. (PBPhP)Rh pivalate complex underwent C-Ph bond activation to yield the pivalate-bridging Rh borane complex.

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