The use of ionic liquids (ILs) as both reagents and solvents is widely recognised. ILs offer a number of advantages compared to regular molecular solvents. These advantages include: chemical and thermal stability, no measurable vapour pressure, no or lower toxicity, non-flammability, catalytic ability, high polarity and they can be recycled. There are a number of research groups investigating the various applications of this reaction medium and most studies have focused on solvents derived from the imidazolium cation. The use of the imidazolium-based ILs in the Diels-Alder reaction has been studied in detail and higher yields compared to conventional methods have been reported. The IL affects the rate and interesting selectivities have been observed. However, not much attention has been paid to the scope and limitations of phosphonium ILs (PILs). Therefore the focus of this thesis is the synthesis and application of novel chiral PILs as environmentally benign, task-specific solvents for the Diels-Alder reaction. In addition, this research seeks alternative ways to eliminate the use of toxic heavy metal catalysts and to exploit methodologies which reduce the energy consumption of the Diels-Alder reaction. A series of CILs were synthesised from the chiral pool and they were characterised by thermogravimetric analysis, differential scanning calorimetry and spectroscopy. They were then investigated as solvents and catalysts in the Diels-Alder reactions of a series of dienes (cyclopentadiene, isoprene, 2,3-dimethylbuta-1,3-diene, furan, pyrrole, N-methyl pyrrole) and dienophiles (methyl acrylate, methyl vinyl ketone, acrylonitrile, dimethyl maleate, acrolein, dimethylacetylene dicarboxylate, maleic anhydride and maleimide). Investigation of the effect of PILs in the presence of three heterogeneous catalysts Al2O3, SiO2 and K-10 montmorillonite were studied. Ultrasound and microwave-assisted Diels-Alder reactions in the PILs, in the absence and presence of the catalysts, were also studied. The reactions of these prototypical substrates illustrated that the solvents are indeed task-specific.

Thesis advisor: James P. Morken / This dissertation details the development, application and study of new palladium-catalyzed carbon-carbon bond forming strategies that generate synthetically useful enantioenriched small molecules. Controlled by a bidentate phosphine ligand, these transformations are thought to operate through a unique 3,3'-reductive elimination that leads to high regio- and stereoselectivity. Specifically, Chapter 1 introduces background on prior work that led to the first allyl-allyl coupling to deliver branched 1,5-dienes, and presents new computational studies on the origins of regioselectivity with mono- and bidentate ligands. Building on these studies, Chapter 2 describes the development of a diastereoselective allyl-allyl coupling of substituted allylboron reagents with allylic chloride electrophiles. To extend the scope of allyl-allyl coupling, Chapter 3 details further reaction optimization and mechanistic studies that have allowed for increasingly congested bond formations. In Chapter 4, a related allyl-propargyl coupling to give enantioenriched 1,5-enynes through stereospecific reactions and kinetic resolution is presented. These developments are accompanied by laboratory and computational data that provide a deeper understanding of reaction mechanisms and the origins of regio- and stereoselectivity. / Thesis (PhD) — Boston College, 2014. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Chemistry.

Os compostos carbonílicos no estado triplete (CCT) são considerados espécies reativas de oxigênio uma vez que possuem comportamento químico semelhante ao de radicais alcoxil. Quando formadas em sistemas biológicos, estas espécies podem estar envolvidas tanto em processos benéficos quanto deletérios ao organismo, como é o caso da lipoperoxidação, onde CCT não só são gerados como também iniciam ou amplificam o processo. Visando estudar a capacidade de dienos conjugados de suprimir a energia triplete de tais compostos, de forma a diminuir seus efeitos deletérios, determinou-se as constantes de supressão, para quatro diferentes dienos, de acetona triplete gerada pela da termólise do tetrametil-1 ,2- dioxetano e pelo sistema enzimático isobutanal/ \"horseradish peroxidase\"/O2 Todos os dienos apresentaram constantes de supressão de ordem difusional. Foi analisada também a forma pela qual os dienos suprimem a acetona triplete e concluiu-se que tanto dienos com hidrogênios alílicos (2,4-hexadienoato e seu éster etílico), potencialmente abstraíveis, quanto dienos sem estes hidrogênios (2 ,4-pentadienoato e seu éster metílico), suprimem a acetona por um processo físico de transferência de energia, que leva à sua fotoisomerização cis,trans. A reatividade destes dienos frente a espécies reativas de oxigênio comumente formadas em sistemas de lipoperoxidação, como o oxigênio singlete, radicais hidroxil, peroxil e superóxido, foi também testada, mostrando que nenhum dos dienos apresenta atividade sequestradora destas espécies. Experimentos preliminares de lipoperoxidação em sistemas biomiméticos (mitocôndrias e microssomos isolados de fígado de rato), mostraram que o trans, trans-2,4-hexadienoato de etila é capaz de inibir o inchamento mitocondrial induzido por benzofenona triplete e de suprimir a quimiluminescência de microssomos induzida por Fe2+/ ascorbato. Concluiu-se assim que dienos conjugados, contendo ou não hidrogênios alílicos, podem ser usados como supressores específicos de compostos carbonílicos triplete em sistemas biológicos e contribuir para o esclarecimento dos mecanismos de reação destes processos. / Triplet carbonyls can be named reactive oxygen species once they behave chemically as alkyloxyl radicals and therefore can potentially drive beneficial and deleterious processes in biological systems. In the case of lipid peroxidation, these species have been found not only to be reaction products but also to amplify the radical chain by hydrogen abstraction of polyunsatured lipid molecules. With the aim of finding efficient and reliable chemical probes for triplet carbonyls, we studied here the quenching properties of conjugated dienes, namely 2,4-hexadienoate and 2,4- pentadienoate anions and corresponding alkyl esters, upon triplet acetone generated either chemically (thermolysis of tetramethyl-1 ,2-dioxetane) or enzymically (aerobic oxidation of isobutanal/horseradish peroxidase). As expected, the quenching rate constants were found to be diffusion controlled, although those for the pentadienoate derivatives were 3-fold lower than those measured for the hexadienoates. Therefore, independently of the presence of allylic hydrogens in the diene probe, the triplet acetone quenching occurred by a physical process followed by cis,trans-isomerization, without hydrogen abstraction from the quencher. The reactivity of the studied dienes towards oxygen reactive species known to be formed during lipid peroxidation, such as singlet oxygen, and peroxyl, hydroxyl and superoxide radicals, was also investigated to assure they would not interfere with the radical lipoperoxidation chain. Indeed, none of the dienes showed antioxidant activity on classical model systems. Preliminary experiments with model systems widely used to study lipid peroxidation showed that the trans, trans-ethyl sorbate can inhibit the mitochondrial swelling induced by enzymically formed triplet benzophenone and to quench the chemiluminescence of microsome preparations challenged with iron/ascorbate. This is in agreement with reported work showing that the lipid peroxidation chain associated with mitochondria permeabilization and polyunsaturated fatty acid peroxidation is amplified by intermediate triplet carbonyl products. Altogether our data indicate that conjugated dienes can be used as specific quenchers of triplet carbonyls formed in biological systems without reacting with other reactive intermediates.

Forty-five Angus steers (358 kg BW) were utilized in a completely randomized block design with a 3 x 3 factorial arrangement of treatments to evaluate the hypothesis that differing dietary linolenic acid (from corn, flaxseed plus corn, or milo) and whole cottonseed (WCS) inclusion (0, 5, or 15% DM) would interact to alter fatty acid metabolism and deposition of conjugated linoleic acid (CLA) in subcutaneous (s.c.) and interfasicular (i.f.) adipose tissues, and thereby decrease carcass quality score. During the feeding period (135 d), steers receiving flaxseed or corn diets had a greater gain:feed ratio (0.119 and 0.108, respectively) than steers receiving the milo diet (0.093). Following transportation to a local abattoir and overnight starvation, there was less decrease in weight in flaxseed-fed steers (1.51%) than in steers fed the corn (2.89%) or milo diets (3.11%). Ribeye area of steers fed milo was less than that of steers fed the corn or flaxseed diets. Lipogenesis from acetate in s.c. adipose tissue was greater in steers fed flaxseed (5.42 nmol h-1 105 cells-1) than in the corn (3.10 nmol h-1 105 cells-1) or milo (1.92 nmol h-1 105 cells-1) groups. Stearoyl-CoA desaturase (SCD) activity in s.c. adipose tissue was unchanged between the 0% WCS group (88.1 nmol mg protein-1 7 min-1) and the 15% WCS group (20 nmol mg protein-1 7 min-1). The i.f. saturated fatty acid percentages increased with increasing levels of WCS. The i.f. cis-9, trans-11 CLA percentage increased with increasing WCS in the steers fed the corn diet, whereas it remained unchanged or even decreased slightly in the steers fed the flaxseed or milo-based diets. Steers fed flaxseed had a greater s.c. adipose concentration of vaccenic acid (18:1trans-11) than the steers fed milo. Steers fed flaxseed also had greater s.c. and i.f. percentages of linolenic acid (18:3, n-3) than steers fed either of the other grain sources. Increased dietary linolenic acid from flaxseed may have increased s.c. adipocyte volume by stimulating lipogenesis. These data indicate that rations formulated to provide increased levels of linolenic acid (i.e., flaxseed) will increase feed efficiency and lipogenesis from acetate without altering either the quality or composition of the beef carcasses.

Natural products continue to influence society at large as many drugs are of natural product origin. Consequently, the development and study of new chemical reactions that lead to the efficient preparation of natural products is a central goal in organic chemistry today. To this end, we have investigated the reactivity and stereoselectivity of cyclic 2-(N-acylamino)-1,3-dienes toward a total synthesis of stenine. Chapter I describes the isolation and characterization of stenine, in addition to comparing five published total syntheses of stenine. Chapter II discusses synthetic and theoretical investigations of cyclic 2-(Nacylamino)- 1,3-dienes. We have shown that vinylazepenes react with Nphenylmaleimide to afford exo cycloadducts exclusively. Previous studies of vinylpiperidenes revealed a preference for endo selectivity. We confirmed the contrasting stereoselectivity by X-ray analysis of compounds i and ii. The stereoselectivity of vinylazepenes, vinylcycloalkenes, and vinyl piperidenes in Diels-Alder reactions varies depending on the detailed structure of the diene. In collaboration with Dr. Daniel Singleton and Jennifer Hirschi, DFT calculations were utilized to study model reactions of these dienes to provide insight into controlling the stereochemistry of this class of Diels-Alder reactions. Chapter III describes the synthesis of compounds such as iv and v that were utilized in intra and intermolecular Diels-Alder approaches toward the synthesis of stenine. We demonstrated that intermediate viii could be constructed from vinyl stannane vii in ten steps via an intermolecular Diels-Alder reaction of v and dimethyl fumarate (vi). Finally, we propose a synthetic plan for the completion of stenine from advanced intermediate viii.

Forty-five Angus steers (358 kg BW) were utilized in a completely randomized block design with a 3 x 3 factorial arrangement of treatments to evaluate the hypothesis that differing dietary linolenic acid (from corn, flaxseed plus corn, or milo) and whole cottonseed (WCS) inclusion (0, 5, or 15% DM) would interact to alter fatty acid metabolism and deposition of conjugated linoleic acid (CLA) in subcutaneous (s.c.) and interfasicular (i.f.) adipose tissues, and thereby decrease carcass quality score. During the feeding period (135 d), steers receiving flaxseed or corn diets had a greater gain:feed ratio (0.119 and 0.108, respectively) than steers receiving the milo diet (0.093). Following transportation to a local abattoir and overnight starvation, there was less decrease in weight in flaxseed-fed steers (1.51%) than in steers fed the corn (2.89%) or milo diets (3.11%). Ribeye area of steers fed milo was less than that of steers fed the corn or flaxseed diets. Lipogenesis from acetate in s.c. adipose tissue was greater in steers fed flaxseed (5.42 nmol h-1 105 cells-1) than in the corn (3.10 nmol h-1 105 cells-1) or milo (1.92 nmol h-1 105 cells-1) groups. Stearoyl-CoA desaturase (SCD) activity in s.c. adipose tissue was unchanged between the 0% WCS group (88.1 nmol mg protein-1 7 min-1) and the 15% WCS group (20 nmol mg protein-1 7 min-1). The i.f. saturated fatty acid percentages increased with increasing levels of WCS. The i.f. cis-9, trans-11 CLA percentage increased with increasing WCS in the steers fed the corn diet, whereas it remained unchanged or even decreased slightly in the steers fed the flaxseed or milo-based diets. Steers fed flaxseed had a greater s.c. adipose concentration of vaccenic acid (18:1trans-11) than the steers fed milo. Steers fed flaxseed also had greater s.c. and i.f. percentages of linolenic acid (18:3, n-3) than steers fed either of the other grain sources. Increased dietary linolenic acid from flaxseed may have increased s.c. adipocyte volume by stimulating lipogenesis. These data indicate that rations formulated to provide increased levels of linolenic acid (i.e., flaxseed) will increase feed efficiency and lipogenesis from acetate without altering either the quality or composition of the beef carcasses.

Tese de doutorado defendida em 2014 ma Pontifícia Universidade Católica do Paraná. / Submitted by Mariliza Portela (mariliza.portela@gmail.com) on 2014-06-05T12:57:34Z No. of bitstreams: 2 SOARES_ElenirTerezinhaPaluch_Tese.pdf: 18305306 bytes, checksum: 8637b291965e6070bf7ac6688a71ab39 (MD5) SOARES_ElenirTerezinhaPaluch_Tese.pdf: 18305306 bytes, checksum: 8637b291965e6070bf7ac6688a71ab39 (MD5) / Made available in DSpace on 2014-06-05T12:57:34Z (GMT). No. of bitstreams: 2 SOARES_ElenirTerezinhaPaluch_Tese.pdf: 18305306 bytes, checksum: 8637b291965e6070bf7ac6688a71ab39 (MD5) SOARES_ElenirTerezinhaPaluch_Tese.pdf: 18305306 bytes, checksum: 8637b291965e6070bf7ac6688a71ab39 (MD5) Previous issue date: 2014-02-12 / Pesquisa que busca compreender o impacto que as contribuições de Dienes para o processo de ensino aprendizagem do Sistema de Numeração Decimal, tiveram na cultura escolar paranaense nas décadas de 1960, 1970 e 1980.

Os compostos carbonílicos no estado triplete (CCT) são considerados espécies reativas de oxigênio uma vez que possuem comportamento químico semelhante ao de radicais alcoxil. Quando formadas em sistemas biológicos, estas espécies podem estar envolvidas tanto em processos benéficos quanto deletérios ao organismo, como é o caso da lipoperoxidação, onde CCT não só são gerados como também iniciam ou amplificam o processo. Visando estudar a capacidade de dienos conjugados de suprimir a energia triplete de tais compostos, de forma a diminuir seus efeitos deletérios, determinou-se as constantes de supressão, para quatro diferentes dienos, de acetona triplete gerada pela da termólise do tetrametil-1 ,2- dioxetano e pelo sistema enzimático isobutanal/ \"horseradish peroxidase\"/O2 Todos os dienos apresentaram constantes de supressão de ordem difusional. Foi analisada também a forma pela qual os dienos suprimem a acetona triplete e concluiu-se que tanto dienos com hidrogênios alílicos (2,4-hexadienoato e seu éster etílico), potencialmente abstraíveis, quanto dienos sem estes hidrogênios (2 ,4-pentadienoato e seu éster metílico), suprimem a acetona por um processo físico de transferência de energia, que leva à sua fotoisomerização cis,trans. A reatividade destes dienos frente a espécies reativas de oxigênio comumente formadas em sistemas de lipoperoxidação, como o oxigênio singlete, radicais hidroxil, peroxil e superóxido, foi também testada, mostrando que nenhum dos dienos apresenta atividade sequestradora destas espécies. Experimentos preliminares de lipoperoxidação em sistemas biomiméticos (mitocôndrias e microssomos isolados de fígado de rato), mostraram que o trans, trans-2,4-hexadienoato de etila é capaz de inibir o inchamento mitocondrial induzido por benzofenona triplete e de suprimir a quimiluminescência de microssomos induzida por Fe2+/ ascorbato. Concluiu-se assim que dienos conjugados, contendo ou não hidrogênios alílicos, podem ser usados como supressores específicos de compostos carbonílicos triplete em sistemas biológicos e contribuir para o esclarecimento dos mecanismos de reação destes processos. / Triplet carbonyls can be named reactive oxygen species once they behave chemically as alkyloxyl radicals and therefore can potentially drive beneficial and deleterious processes in biological systems. In the case of lipid peroxidation, these species have been found not only to be reaction products but also to amplify the radical chain by hydrogen abstraction of polyunsatured lipid molecules. With the aim of finding efficient and reliable chemical probes for triplet carbonyls, we studied here the quenching properties of conjugated dienes, namely 2,4-hexadienoate and 2,4- pentadienoate anions and corresponding alkyl esters, upon triplet acetone generated either chemically (thermolysis of tetramethyl-1 ,2-dioxetane) or enzymically (aerobic oxidation of isobutanal/horseradish peroxidase). As expected, the quenching rate constants were found to be diffusion controlled, although those for the pentadienoate derivatives were 3-fold lower than those measured for the hexadienoates. Therefore, independently of the presence of allylic hydrogens in the diene probe, the triplet acetone quenching occurred by a physical process followed by cis,trans-isomerization, without hydrogen abstraction from the quencher. The reactivity of the studied dienes towards oxygen reactive species known to be formed during lipid peroxidation, such as singlet oxygen, and peroxyl, hydroxyl and superoxide radicals, was also investigated to assure they would not interfere with the radical lipoperoxidation chain. Indeed, none of the dienes showed antioxidant activity on classical model systems. Preliminary experiments with model systems widely used to study lipid peroxidation showed that the trans, trans-ethyl sorbate can inhibit the mitochondrial swelling induced by enzymically formed triplet benzophenone and to quench the chemiluminescence of microsome preparations challenged with iron/ascorbate. This is in agreement with reported work showing that the lipid peroxidation chain associated with mitochondria permeabilization and polyunsaturated fatty acid peroxidation is amplified by intermediate triplet carbonyl products. Altogether our data indicate that conjugated dienes can be used as specific quenchers of triplet carbonyls formed in biological systems without reacting with other reactive intermediates.

The use of ionic liquids (ILs) as both reagents and solvents is widely recognised. ILs offer a number of advantages compared to regular molecular solvents. These advantages include: chemical and thermal stability, no measurable vapour pressure, no or lower toxicity, non-flammability, catalytic ability, high polarity and they can be recycled. There are a number of research groups investigating the various applications of this reaction medium and most studies have focused on solvents derived from the imidazolium cation. The use of the imidazolium-based ILs in the Diels-Alder reaction has been studied in detail and higher yields compared to conventional methods have been reported. The IL affects the rate and interesting selectivities have been observed. However, not much attention has been paid to the scope and limitations of phosphonium ILs (PILs). Therefore the focus of this thesis is the synthesis and application of novel chiral PILs as environmentally benign, task-specific solvents for the Diels-Alder reaction. In addition, this research seeks alternative ways to eliminate the use of toxic heavy metal catalysts and to exploit methodologies which reduce the energy consumption of the Diels-Alder reaction. A series of CILs were synthesised from the chiral pool and they were characterised by thermogravimetric analysis, differential scanning calorimetry and spectroscopy. They were then investigated as solvents and catalysts in the Diels-Alder reactions of a series of dienes (cyclopentadiene, isoprene, 2,3-dimethylbuta-1,3-diene, furan, pyrrole, N-methyl pyrrole) and dienophiles (methyl acrylate, methyl vinyl ketone, acrylonitrile, dimethyl maleate, acrolein, dimethylacetylene dicarboxylate, maleic anhydride and maleimide). Investigation of the effect of PILs in the presence of three heterogeneous catalysts Al2O3, SiO2 and K-10 montmorillonite were studied. Ultrasound and microwave-assisted Diels-Alder reactions in the PILs, in the absence and presence of the catalysts, were also studied. The reactions of these prototypical substrates illustrated that the solvents are indeed task-specific. / University of Bradford

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