Actualmente, el interés industrial de los productos carbonilados ha atraído la atención de los científicos hacia el desarrollo de nuevos sistemas catalíticos eficientes. La reacción de alcoxicarbonilación de vinil arenos ha sido considerada una ruta alternativa para la obtención de ácidos 2-aril propiónicos, la clase más importante de antiinflamatorios no esteroides. Por otro lado, los copolímeros de monóxido de carbono y olefinas son materiales de gran interés industrial debido a su aplicación potencial como termoplásticos. El concepto de economía atómica ha influenciado el desarrollo de los procesos catalíticos industriales. El máximo aprovechamiento de los reactivos y la disminución de residuos han hecho de la catálisis un proceso altamente atractivo en el marco de tecnologías de desarrollo sostenible. El conocimiento de los mecanismos operantes en las reacciones de carbonización es de gran importancia para el diseño de nuevos sistemas catalíticos altamente efectivos.Basándose en las consideraciones anteriores, el primer objetivo de esta tesis se ha centrado en el desarrollo de nuevos sistemas catalíticos de paladio y su aplicación en la metoxicarbonilación asimétrica de vinil arenos, con el fin de obtener altas regio- y enantioselectividades, simultáneamente. Un segundo objetivo, ha sido el desarrollo de nuevos catalizadores catiónicos de paladio y el estudio de su actividad catalítica en las reacciones de co- y terpolimerización de CO/etileno/propileno. Para alcanzar el primer objetivo, se ha planteado la exploración de complejos de paladio modificados con fosfinas monodentadas y fosfinas bidentadas. Con el fin de conocer mejor ambos sistemas e identificar algunos intermedios de reacción, se llevó a cabo un estudio de la metoxicarbonilación de estireno bajo condiciones similares a las catalíticas. Para lograr el segundo objetivo, se han sintetizado nuevos catalizadores de paladio catiónicos modificados con difosfinas derivadas de D-(+)-xilofuranosa. Los nuevos complejos se aplicaron en las reacciones de copolimerización de CO/etileno y CO/propileno, así como, en la terpolimerización CO/etileno/propileno. Después de revisar los antecedentes bibliográficos en la introducción y planteados los objetivos, en el Capítulo 2 "Palladium complexes bearing monodentate ligands in asymmetric methoxycarbonylation of vinyl arenes" se presenta la síntesis y caracterización de complejos de paladio modificados con fosfinas cíclicas quirales, tales como, fosfetanos, fosfolanos y fosfepinos. Estos nuevos complejos se aplican en la metoxicarbonilación asimétrica de vinil arenos, mostrando que la actividad decrece a medida que aumenta el número de miembros del ciclo fosforado.En el Capítulo 3 "Palladium complexes bearing bidentate ligands in asymmetric methoxycarbonylation of styrene" se describe la aplicación de complejos de paladio neutros y catiónicos modificados con ligandos bidentados, en la metoxicarbonilación asimétrica de estireno. Los ligandos ultilizados en este capítulo presentan propiedades estéricas y electrónicas diferentes. En términos generales, para los sistemas neutros y catiónicos, la presencia de sustituyentes electroatractores en los grupos fenilos del ligando, tiene una gran influencia sobre la regioselectividad de la reacción hacia el producto ramificado. En el Capítulo 4 "Mechanistic aspects of the methoxycarbonylation of styrene" se discuten algunos aspectos mecanísticos de la metoxicarbonilación de estireno, utilizando complejos de paladio modificados con ligandos monodentados y bidentados. La reactividad de los complejos con los diferentes componentes del sistema catalítico, se llevó a cabo paso a paso y mediante experimentos in situ en condiciones similares a las empleadas en la catálisis.Finalmente en el Capítulo 5 "Cationic palladium complexes bearing xylofuranose-derivative diphosphines in CO/ethene/propene co- and terpolymerisation reactions" se describe la síntesis de una difosfina derivada de la D-(+)-xilofuranosa, así como la síntesis y caracterización de nuevos complejos neutros y catiónicos. Los resultados obtenidos han sido comparados con los complejos análogos modificados con dppp y o-MeO-dppp, con el fin de discutir cómo afectan los efectos electrónicos y la rigidez del ligando en la copolimerización perfectamente alternada. / Nowadays the industrial interest of the carbonylated products has attracted the attention of scientists towards the development of new efficient catalytic systems. The alcoxycarbonylation of vinyl arenes has been considered an alternative route to obtain 2-aryl propionic acids, the most important class of non-steroidal anti-inflammatory drugs. Copolymers formed by carbon monoxide and alkenes are materials of industrial interest due to their potential application as engineering thermoplastics. The concept of atomic economy has influenced the development of industrial catalytic processes. The waste diminishing by the complete conversion of reagents into the desired product in a catalytic process introduce the homogeneous catalysis as an attractive sustainable technology. The knowledge of the carbonylation mechanisms is of great importance for the design of new highly efficient catalytic systems.Based on these considerations, the first objective of this thesis was to develop new catalytic palladium systems and its application in the asymmetric methoxycarbonylation of vinyl arenes, in order to obtain high regio-and enantioselectivities simultaneously. The second objective was to synthesise new cationic palladium complexes and to study the activity in the copolymerisation reaction. To achieve the first objective, palladium complexes modified with monodentate and bidentate phosphine ligands were explored. In order to know more about the influence of the nature of the ligand on the mechanism, a mechanistic study under similar conditions to those used in the catalysis was performed. To achieve the second objective new cationic palladium complexes modified with diphosphine ligands derived from D-(+)-xylofuranose were synthesised. The new complexes were tested in the CO/ethene, CO/propene copolymerisation reaction, as well as in the CO/ethene/propene terpolymerisation process. Chapter 2 "Palladium complexes bearing monodentate ligands in asymmetric methoxycarbonylation of vinyl arenes" shows the use of chiral monodentate cyclic phosphines, such as phosphetane, phospholane and binepine, in the palladium-catalysed asymmetric methoxycarbonylation of vinyl arenes. New neutral palladium complexes are synthesised and characterised by multinuclear NMR spectroscopy. This new complexes were showed a decreased in the catalytic activity when increased the number of the phosphorus membered ring.Chapter 3 "Palladium complexes bearing bidentate ligands in asymmetric methoxycarbonylation of vinyl arenes" describes the synthesis of neutral and cationic complexes bearing bidentate ligands with different electronic and steric properties and its application in the methoxycarbonylation of vinyl arenes. In general terms, it was observed that the presence of electron withdrawing groups in the phenyl moiety of the ligand has an influence on the regioselectivity of the reaction to the branched ester. Chapter 4 "Mechanistic aspects of the methoxycarbonylation of styrene" discusses mechanistic aspects of the methoxycarbonylation reaction. In situ studies are performed under similar conditions to those used in the catalytic studies. The studies are focuses in palladium systems modified with mono- and bidentate ligands, in order to establish comparison between them. The characterisation of some species by NMR spectroscopy is showed.Finally in Chapter 5 "Cationic palladium complexes bearing xylofuranose-derivative diphosphines in CO/ethene/propene co- and terpolymerisation reactions" it was discussed the electronic effects of xylose-derivatives diphosphines ligands in the CO/ethene/propene co- and ter-polymerisation processes. The new diphosphines o-MeO-xylophos is synthesised. A series of new neutral and cationic palladium complexes bearing xylophos and o-MeO-xylophos were synthesised and fully characterised by multinuclear NMR techniques. The catalytic polymerisation reactions were performed in methanol using the cationic complexes and are compared to the reaction catalysed by analogous complexes bearing dppp and o-MeO-dppp to determine the electronic effects and the backbone rigidity on the perfectly alternating copolymerisation.

Ruthenium-catalyzed cycloadditions of bicyclic alkenes with alkynyl phosphonates were investigated. In regard to the Ru-catalyzed [2+2] cycloadditions, the phosphonate moieties were found to be compatible, giving the corresponding cyclobutene cycloadducts in low to excellent yield (up to 96%). Alkynyl phosphonates showed lower reactivity than other heteroatom-substituted alkynes such as alkynyl halides, ynamides, alkynyl sulfides and alkynyl sulfones, and required a higher reaction temperature and much longer reaction time. To this end microwave heating was employed to expedite the reaction. While yields comparable to the conventionaly heated cycloadditions were not achieved, the reaction was much faster by microwave heating. In direct comparison over a 2 h period, yields were much greater in the microwave heated reactions. Computational studies determined that the electronic nature of the triple bond is sufficiently different in alkynyl phosphonates compared to other substituents. While investigating solvents of varying polarity in the microwave assisted [2+2] cycloaddition a new mode of reaction, previously unknown to this catalyst, was discovered. At elevated temperatures, in polar solvents, norbornadiene undergoes a Ru-catalyzed [2+2+2] homo Diels-Alder cycloaddition with alkynyl phophonates. This reaction was optimized to produce excellent yields with the model alkynyl phosphonate studied. Investigation of other alkynes revealed that the scope of this reaction may be limited to phosphonate substituted alkynes.

This thesis examines the various aspects of catalytically deoxygenating biomass-derived feedstocks including the relevant catalyst materials, conditions and equipment. Preliminary investigations probed the ability of T316 SS, as a reactor material, to perform as an effective hydrogenation catalyst at temperatures above 100 oC, under reducing aqueous-acidic media. Additionally, an external apparatus was developed in order to facilitate the optimization of catalytic hydrogenations. The accuracy and applicability of this system was confirmed using the reduction of levulinic acid to γ-valerolactone. Accurate information pertaining to the quantity of hydrogen consumed was obtained in addition to in situ differential rates reaction allowing for the derivation of the integrated rate law. Subsequently, the newly designed uptake system was used to monitor, and effectively optimize, the deoxygenation of a series of complex furfural-derived substrates towards the attempted production of high-energy density fuels. Commercially available Pd/C and Ru/C catalysts were employed, unsuccessfully, under a variety of reaction conditions. / NSERC, Los Alamos National Laboratories, Ontario Innovation Trust

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A methodology for the catalytic asymmetric hydroboration of vinylarenes with pinacolborane has been developed. Use of pinacolborane in hydroboration, especially catalytic asymmetric hydroboration grants direct access to chiral boronate esters, without the cryogenic temperatures required for catalytic hydroboration with catecholborane and the subsequent transesterification with excess pinacol. These chiral boronate esters were then subjected to a homologation/oxidation sequence previously refined in our labs to prepare Naproxen™ in 66% yield and 88% enantiopurity from its corresponding vinyl arene precursor. A survey of metal catalysts, solvents and ligands revealed remarkable changes in regioselectivity with changes in metal. Rhodium catalysts in combination with pinacolborane were able to provide regioselectivity for the secondary branched isomer equivalent to those obtained with catecholborane. Iridium catalysts showed a near perfect regioselectivity for the primary linear isomer. With respect to the choice of chiral ligand, complete reversal in the enantiomer obtained was observed with the choice of hydroborating reagent from catecholborane to pinacolborane. In order to understand the regioselectivity observed under iridium catalysis, deuterium labeling studies were undertaken. A synthesis of the deuterated hydroboration reagent pinacolborane was first completed. From the results of these studies, in combination with published thermodynamic data, a mechanism for the iridium catalyzed hydroboration of alkenes was proposed. / Thesis (Ph.D, Chemistry) -- Queen's University, 2007-08-29 09:30:38.571

Enormous efforts have been made to optimize the Pd-catalyzed Suzuki-Miyaura reaction, but there is to date no generally useful protocol and forcing conditions are often required. One reaction variable that has often been neglected is the extent to which the supposed catalysts, bisphosphinepalladium(0) complexes, are actually formed from the variety of popular precatalysts used. There is in fact little evidence that these precursors produce bis-ligated Pd(0) complexes and it is possible that the rate limiting factor may be catalyst formation. If so, then the development of an optimized method for forming these catalytic species would be a significant contribution to this field. The following work describes research efforts to determine the optimum conditions to generate PdL2 (L = PCy3, PMeBut2, PBut3) cleanly and quantitatively from Pd(3-C3H5)(5-C5H5) and Pd(3-1-Ph-C3H5)(5-C5H5). Furthermore, the conditions under which PdL3 species may exist in equilibrium with the PdL2 species are defined. NMR studies indicate that while Pd(PBut3)2 shows no inclination to increase its coordination number, Pd(PCy3)2 and Pd(PMeBut2)2 react with added phosphine to form 3:1 compounds. Equilibrium constants for dissociation of the PdL3 compounds were measured over a range of temperatures, yielding the thermodynamic parameters of dissociation and estimated Pd-P bond dissociation energies. Additionally, the generation of heteroleptic species serve to confirm the existence of 3:1 compounds. A kinetic study of the oxidative addition of PhBr to Pd(PCy3)2 was also performed. It was found that oxidative addition was first order in palladium, but that added bromide had no effect on the rate of oxidative addition. Added PCy3 inhibited oxidative addition, possibly due to the conversion of palladium(0) into the less active 3:1 compound. The formation of the catalytically less active 3:1 compounds has serious implications for many catalytic cross-coupling processes which involve catalyst formation via the slow reduction of palladium(II) in the presence of excess phosphine; for many systems, relatively little of the added palladium may actually be present as the active bisphosphinepalladium(0) compound. / Thesis (Ph.D, Chemistry) -- Queen's University, 2008-12-08 13:24:50.825