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Artigos de revistas sobre o assunto "Iodure hypervalent"
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Kiyokawa, Kensuke, e Satoshi Minakata. "Iodine-Based Reagents in Oxidative Amination and Oxygenation". Synlett 31, n.º 09 (26 de fevereiro de 2020): 845–55. http://dx.doi.org/10.1055/s-0039-1690827.
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In this Account, we provide an overview of our recent advances in oxidative transformations that enable the introduction of nitrogen and oxygen functionalities into organic molecules by taking advantage of the unique characteristics of iodine-based reagents, such as hypervalency, soft Lewis acidity, high leaving ability, and radical reactivity. We also report on the development of new types of hypervalent iodine reagents containing a transferable nitrogen functional group with the objective of preparing primary amines, which is described in the latter part of this Account.1 Introduction2 Decarboxylative Functionalization of β,γ-Unsaturated Carboxylic Acids3 Decarboxylative Functionalization at Tertiary Carbon Centers4 C–H Bond Functionalization at Tertiary Carbon Centers5 Intramolecular C–H Amination of Sulfamate Esters and N-Alkylsulfamides6 Oxidative Amination with Hypervalent Iodine Reagents Containing Transferable Nitrogen Functional Groups7 Summary and Outlook
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Dearman, Samuel M. G., Xiang Li, Yang Li, Kuldip Singh e Alison M. Stuart. "Oxidative fluorination with Selectfluor: A convenient procedure for preparing hypervalent iodine(V) fluorides". Beilstein Journal of Organic Chemistry 20 (29 de julho de 2024): 1785–93. http://dx.doi.org/10.3762/bjoc.20.157.
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The ability to investigate hypervalent iodine(V) fluorides has been limited primarily by their difficult preparation traditionally using harsh fluorinating reagents such as trifluoromethyl hypofluorite and bromine trifluoride. Here, we report a mild and efficient route using Selectfluor to deliver hypervalent iodine(V) fluorides in good isolated yields (72–90%). Stability studies revealed that bicyclic difluoro(aryl)-λ5-iodane 6 was much more stable in acetonitrile-d3 than in chloroform-d1, presumably due to acetonitrile coordinating to the iodine(V) centre and stabilising it via halogen bonding.
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Goesten, Maarten G., Roald Hoffmann, F. Matthias Bickelhaupt e Emiel J. M. Hensen. "Eight-coordinate fluoride in a silicate double-four-ring". Proceedings of the National Academy of Sciences 114, n.º 5 (17 de janeiro de 2017): 828–33. http://dx.doi.org/10.1073/pnas.1615742114.
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Fluoride, nature’s smallest anion, is capable of covalently coordinating to eight silicon atoms. The setting is a simple and common motif in zeolite chemistry: the box-shaped silicate double-four-ring (D4R). Fluoride seeks its center. It is the strain of box deformation that keeps fluoride in the middle of the box, and freezes what would be a transition state in its absence. Hypervalent bonding ensues. Fluoride’s compactness works to its advantage in stabilizing the cage; chloride, bromide, and iodide do not bring about stabilization due to greater steric repulsion with the box frame. The combination of strain and hypervalent bonding, and the way they work in concert to yield this unusual case of multiple hypervalence, has potential for extension to a broader range of solid-state compounds.
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Kuhn, Norbert, Qutaiba Abu-Salem, Torben Gädt, Steffi Reit e Manfred Steimann. "Trimethyl(4-Iodophenyl)Ammoniumiodid, Eine Hypervalente Verbindung Des Iods". Zeitschrift für Naturforschung B 62, n.º 6 (1 de junho de 2007): 871–72. http://dx.doi.org/10.1515/znb-2007-0619.
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LaMartina, Kelsey B., Haley K. Kuck, Linda S. Oglesbee, Asma Al-Odaini e Nicholas C. Boaz. "Selective benzylic C–H monooxygenation mediated by iodine oxides". Beilstein Journal of Organic Chemistry 15 (5 de março de 2019): 602–9. http://dx.doi.org/10.3762/bjoc.15.55.
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A method for the selective monooxdiation of secondary benzylic C–H bonds is described using an N-oxyl catalyst and a hypervalent iodine species as a terminal oxidant. Combinations of ammonium iodate and catalytic N-hydroxyphthalimide (NHPI) were shown to be effective in the selective oxidation of n-butylbenzene directly to 1-phenylbutyl acetate in high yield (86%). This method shows moderate substrate tolerance in the oxygenation of substrates containing secondary benzylic C–H bonds, yielding the corresponding benzylic acetates in good to moderate yield. Tertiary benzylic C–H bonds were shown to be unreactive under similar conditions, despite the weaker C–H bond. A preliminary mechanistic analysis suggests that this NHPI-iodate system is functioning by a radical-based mechanism where iodine generated in situ captures formed benzylic radicals. The benzylic iodide intermediate then solvolyzes to yield the product ester.
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Zhdankin, V. "APPLICATION OF HYPERVALENT IODINE COMPOUNDS IN ADVANCED GREEN TECHNOLOGIES". Resource-Efficient Technologies, n.º 1 (14 de maio de 2021): 1–16. http://dx.doi.org/10.18799/24056529/2021/1/286.
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This review summarizes industrial applications of inorganic and organic polyvalent (hypervalent) iodine compounds. Inorganic iodate salts have found some application as a dietary supplements and food additives. Iodine pentafluoride is used as industrial fluorinating reagent, and iodine pentoxide is a powerful and selective oxidant that is particularly useful in analytical chemistry. Common organic hypervalent iodine reagents such as (dichloroiodo)benzene and (diacetoxyiodo)benzene are occasionally used in chemical industry as the reagents for production of important pharmaceutical intermediates. Iodonium salts have found industrial application as photoinitiators for cationic photopolymerizations. Various iodonium compounds are widely used as precursors to [18F]-fluorinated radiotracers in the Positron Emission Tomography (PET).
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Zhang, Chi, Xiao-Guang Yang, Ze-Nan Hu, Meng-Cheng Jia e Feng-Huan Du. "Recent Advances and the Prospect of Hypervalent Iodine Chemistry". Synlett 32, n.º 13 (27 de abril de 2021): 1289–96. http://dx.doi.org/10.1055/a-1492-4943.
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AbstractNowadays, hypervalent iodine chemistry has remarkably advanced in parallel with the emergence of novel hypervalent iodine reagents. Hypervalent iodine reagents, due to their outstanding characteristics including rich reactivities, excellent chemoselectivity, stability, and environmental friendliness, are becoming more and more popular in the synthetic organic chemistry. In this Account, a number of recent elegant research works and our perspective on the future of hypervalent iodine chemistry is presented.1 Introduction2 Recent Advances and Discussion2.1 Novel Reactivities of Hypervalent Iodine Reagents2.2 Atom-Economical Reactions Promoted by Hypervalent Iodine Reagents2.3 Other Applications of Hypervalent Iodine Reagents2.4 The Applications of DFT Calculations in Elucidating Reaction Mechanism Involving Hypervalent Iodine Reagents3 Outlook and Conclusion
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Maegawa, Tomohiro, Yasuyoshi Miki, Ryohei Oishi, Kazutoshi Segi, Hiromi Hamamoto e Akira Nakamura. "Hypervalent Iodine-Mediated Beckmann Rearrangement of Ketoximes". Synlett 29, n.º 11 (23 de abril de 2018): 1465–68. http://dx.doi.org/10.1055/s-0037-1609686.
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We developed a Beckmann rearrangement employing hypervalent iodine reagent under mild conditions. The reaction of ketoxime with hypervalent iodine afforded the corresponding ketone, but premixing of hypervalent iodine and a Lewis acid was effective for promoting Beckmann rearrangement. Aromatic and aliphatic ketoximes were converted into their corresponding amides in good to high yields.
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Xing, Linlin, Yong Zhang e Yunfei Du. "Hypervalent Iodine-Mediated Synthesis of Spiroheterocycles via Oxidative Cyclization". Current Organic Chemistry 23, n.º 1 (13 de março de 2019): 14–37. http://dx.doi.org/10.2174/1385272822666181211122802.
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Hypervalent iodine reagents have been widely used in the construction of many important building blocks and privileged scaffolds of bioactive natural products. This review article aims to briefly discuss strategies that have used hypervalent iodine reagents as oxidants to synthesize spiroheterocyclic compounds and to stimulate further study for novel syntheses of spiroheterocyclic core structures using hypervalent iodine reagents under metal-free conditions.
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Mowdawalla, Cyrus, Faiz Ahmed, Tian Li, Kiet Pham, Loma Dave, Grace Kim e I. F. Dempsey Hyatt. "Hypervalent iodine-guided electrophilic substitution: para-selective substitution across aryl iodonium compounds with benzyl groups". Beilstein Journal of Organic Chemistry 14 (14 de maio de 2018): 1039–45. http://dx.doi.org/10.3762/bjoc.14.91.
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The reactivity of benzyl hypervalent iodine intermediates was explored in congruence with the reductive iodonio-Claisen rearrangement (RICR) to show that there may be an underlying mechanism which expands the reasoning behind the previously known C–C bond-forming reaction. By rationalizing the hypervalent iodine’s metal-like properties it was concluded that a transmetallation mechanism could be occurring with metalloid groups such as silicon and boron. Hypervalent iodine reagents such as Zefirov’s reagent, cyclic iodonium reagents, iodosobenzene/BF3, and PhI(OAc)2/BF3 or triflate-based activators were tested. A desirable facet of the reported reaction is that iodine(I) is incorporated into the product thus providing greater atom economy and a valuable functional group handle for further transformations. The altering of the RICR’s ortho-selectivity to form para-selective products with benzyl hypervalent iodine intermediates suggests a mechanism that involves hypervalent iodine-guided electrophilic substitution (HIGES).
Teses / dissertações sobre o assunto "Iodure hypervalent"
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Jaussaud, Quentin. "Génération in situ d’isocyanates par décarboxylation d’acides oxamiques pour l’élaboration de matériaux polyuréthanes". Electronic Thesis or Diss., Bordeaux, 2024. http://www.theses.fr/2024BORD0139.
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Ces travaux de thèse portent sur la synthèse de polyuréthanes par génération in situ d’isocyanates, à travers différentes voies de moindre toxicité que la voie classique faisant appel à l’utilisation directe d’isocyanates. Dans un premier temps, la décarboxylation oxydante des acides oxamiques conduisant à la formation d’isocyanates a été réalisée par activation thermique grâce à l’utilisation d’un iodure hypervalent, jouant le rôle d’oxydant. Une étude cinétique sur des réactions modèles en présence d’alcool, associé à une modélisation numérique, ont notamment mis en évidence un effet catalytique de l’acide acétique, sous-produit de la réaction, sur la formation de liaisons uréthane. La formation de CO2 généré par cette réaction menant à la formation d’isocyanates, a ensuite été exploitée, pour la synthèse de mousses polyuréthanes réticulées. Les effets de différents paramètres, tels la nature des monomères ou la température de réaction, sur la morphologie et les propriétés des mousses obtenues ont ensuite été étudiés. Cette réaction d’activation des acides oxamiques a ensuite été réalisée par irradiation lumineuse en présence d’un photocatalyseur, permettant d’élaborer des films polyuréthanes. La modification des composés du mélange réactionnel a permis de développer des formulations homogènes, notamment en changeant la nature de l’iodure hypervalent utilisé. Enfin, la synthèse d’uréthanes et de polyuréthanes à partir de 1,4,2-dioxazol-5-ones a été explorée. Après une optimisation des conditions catalytiques permettant la génération d’isocyanates par ouverture de ces hétérocycles, le CO2 aussi formé a été exploité pour la production de mousses polyuréthanesThis PhD work focus on the synthesis of polyurethanes through the in situ generation of isocyanates, using pathways with lower toxicity compared to the classical approach involving the direct use of isocyanates. The oxidative decarboxylation of oxamic acids leading to the formation of isocyanates was, first, carried out by thermal activation using a hypervalent iodine as an oxidant. A kinetic study on model reactions in the presence of alcohol, combined with computational modeling, notably revealed a catalytic effect of acetic acid, a by-product of the reaction, on the formation of urethane bonds. The CO2 generated by this reaction, leading to the formation of isocyanates, was then exploited for the synthesis of cross-linked polyurethane foams. The effects of various parameters, such as the nature of the monomers or the reaction temperature, on the morphology and properties of the obtained foams were thereafter studied. This activation reaction of oxamic acids was then carried out by light irradiation in the presence of a photocatalyst, allowing the production of polyurethane films. Modifying the components of the reaction mixture enabled the development of homogeneous formulations, particularly by changing the nature of the hypervalent iodine used. Finally, the synthesis of urethanes and polyurethanes from 1,4,2-dioxazol-5-ones was explored. After optimizing the catalytic conditions for generating isocyanates through the opening of these heterocycles, the generated CO2 was exploited for the production of polyurethane foams
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Antien, Kevin. "Développement de nouveaux réactifs iodés hypervalents chiraux hélicéniques. Synthèse collective stéréodivergente d’alcaloïdes de Securinega". Thesis, Bordeaux, 2018. http://www.theses.fr/2018BORD0349/document.
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La chimie des composés iodés hypervalents, ou organoiodanes, suscite un engouement croissant de la part de la communauté scientifique depuis maintenant près de 30 ans. Les efforts de recherche sont de nos jours orientés de manière prépondérante vers des applications en synthèse asymétrique, principalement au travers de l’utilisation d’architectures organoiodées chirales. À ce jour, seules les chiralités centrales et axiales sont exploitées dans l’élaboration de tels objets. L’emploi d’iodanes achiraux (i.e. en synthèse asymétrique) en présence d’additifs chiraux a par ailleurs été largement négligé par la communauté. La chiralité hélicoïdale est incarnée en chimie organique par les hélicènes. Ces composés polyaromatiques sont des objets fascinants de par leurs propriétés structurelles, électroniques et chiroptiques hors du commun. Ils sont le centre d’une attention considérable dans de nombreux domaines de recherches allant de la catalyse asymétrique à l’élaboration de diodes électroluminescentes organiques. Jamais la chiralité hélicoïdale n’a été exploitée en chimie de l’iode hypervalent. Ces travaux de thèse traitent en premier lieu de l’élaboration d’une méthodologie asymétrique de désaromatisation oxygénante de phénols faisant usage d’un iodane-3 achiral en présence d’un agent de transfert de phase issu des alcaloïdes du Quinquina. Dans une seconde partie de ces travaux est abordée la synthèse asymétrique d’un nouvel iodoarène hélicénique et ses premières applications dans des réactions de désaromatisation oxygénante de phénols. Cet ouvrage traite également dans un troisième chapitre d’une synthèse totale, collective et stéréodivergente de 12 alcaloïdes de Securinega. Il s’agit d’une classe métabolites secondaires retrouvés dans de multiples plantes des genres Securinega (Flueggea), Phyllanthus, Margaritaria et Breynia de la famille Phyllanthaceae. Depuis près d’un demi-siècle, la biogénèse de ces molécules naturelles demeure partiellement incomprise. La synthèse développée dans ce travail a pour vocation d’améliorer la compréhension du mécanisme biosynthétique à l’origine de ces substances. Il a ainsi été établi qu’une étape clé de condensation aldolique pourrait permettre d’expliquer la stéréodivergence observée dans la natureHypervalent iodine chemistry has been arousing the interest of the scientific community for the last 30 years. Research efforts are now mainly directed towards applications in asymmetric synthesis, notably through the use of chiral organoiodine scaffolds. To this end, solely central and axial chiralities have been exploited to construct such objects. The use of achiral iodanes (i.e. hypervalent organoiodine compounds) in asymmetric synthesis has been largely neglected by the community. Helical chirality in organic synthesis is mainly found in polyaromatic compounds known as helicenes. These molecules exhibit fascinating structural, electronic and chiroptical properties. They are the center of considerable attention across many fields of research, spanning from asymmetric catalysis to organic light-emitting diodes. Helical chirality has never been exploited in the field of hypervalent iodine chemistry. In the first part of this doctoral work, a methodology for the asymmetric oxygenative dearomatization of phenols by an achiral 3-iodane in the presence of a Cinchona-alkaloid-based phase transfer agent was developed. The second part of this manuscript details the synthesis of a new helicenic organoiodine compound and its application to oxygenative phenol dearomatization reactions. In the last chapter of this doctoral dissertation is described the total, collective and stereodivergent synthesis of 12 Securinega alkaloids. These natural products are commonly found in plants belonging to the genera Securinega (Flueggea), Phyllanthus, Margaritaria and Breynia of the Phyllanthaceae family. Even after little less than half a century of research, the real biogenetic pathway used by nature to construct these molecules is still only partly understood. The chemical synthesis developed in this doctoral work provides a better understanding of the biosynthetic mechanism. It was established in the course of this work that a key aldol condensation step could shed light upon the stereodivergence observed in nature
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Nocquet-Thibault, Sophie. "La difonctionnalisation d’énamides en utilisant des dérivés d’iode (III) hypervalent". Thesis, Paris 11, 2014. http://www.theses.fr/2014PA112270/document.
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Lors de ce travail de thèse qui visait à développer une méthode générale d’introduction d’halogénures et de pseudo-halogénures en se basant sur l’utilisation de réactifs d’iode hypervalent en tant que promoteurs d’umpolung, diverses avancées ont pu être accomplies. Tout d’abord, une réaction d'alkoxybromation régiosélective mettant en jeu des sels de bromure et du PIDA a été mise au point. Un des intérêts de cette réaction réside dans l'utilisation de LiBr peu coûteux comme source d'halogène électrophile (par inversion de polarité : umpolung). En outre, l'introduction de deux groupements de manière chimio- et régiosélective est possible sans recourir à l'utilisation d’un catalyseur métallique. Une large gamme d'énamides a été testée et les rendements sont généralement excellents (au dessus de 75 %) et les réactions rapides (moins d’une heure). En outre, la diastéréosélectivité oscille entre modérée et excellente. Ces produits éthoxybromés se sont aussi montrés très polyvalents et permettent l’accès à de nombreux motifs structuraux. Une version asymétrique de cette réaction en faisant intervenir des dérivés d’iode hypervalent chiraux n’a pas été couronnée de succès tout comme l’introduction de copules chirales. Le but initial était de mettre au point une méthode générale de difonctionnalisation d’énamides avec l’insertion d’halogénures. C’est pourquoi, notre stratégie a ensuite été étendue au chlore et une réaction d’éthoxychloration a été développée avec des rendements moyens à très bons (de 36% à 86%) un temps de réaction rapide (généralement autour de 30 minutes) et une diastéréosélectivité moyenne à très bonne (de 55/45 à 92/8). Les deux réactions d’éthoxybromation et d’éthoxychloration ont fait l’objet d’une investigation mécanistique (notamment par spectrométrie de masse) et il semblerait que le mécanisme soit ionique. Nous avons alors voulu appliquer cette méthodologie au fluor, élément dont l’introduction sélective sur un substrat est rarement triviale. En accord avec la littérature, nous avons conclu que le fluor ne pouvait être transféré directement en tant qu’électrophile. Enfin, une version d’éthoxyiodation a été validée et est en cours d’optimisation au laboratoire. Concernant les pseudo-halogénures, nous nous sommes uniquement intéressés aux azotures. Ayant réalisé qu’une réaction d’éthoxyazidation ne serait pas possible, une étude poussée des différents paramètres réactionnels adossée à la compréhension des mécanismes mis en jeu a été entreprise. Deux méthodologies ont alors pu être mises au point : une réaction de diazidation dont les rendements sont modérés ( entre 20% et 52%), les temps de réaction courts (environ 1 h) et des diastéréosélectivités moyennes à bonnes (entre 75/25 et 90/10) ainsi qu’une réaction d’oxyamination qui se montre bien plus efficace avec des rendements moyens à très bons (de 31% à 95%), des temps de réaction assez rapides (autour de 2 h), des diastéréosélectivités souvent excellentes (supérieures à 67/33) et un champ d’application bien plus large (Schéma 245). Ces deux méthodes réunies représentent un outil utile pour l’obtention de composés à la fois azotés et azidés. Dans ce cas, les intermédiaires réactionnels semblent être radicalaires même si des études complémentaires restent à effectuer.L’intérêt synthétique de ces deux types de composés a aussi fait l’objet de diverses études. Si la réduction du groupement azido en amine n’a pas pu être systématiquement accomplie, des réactions de cyclisation d’Huisgen sur les produits diazidés ont cependant fonctionné (les produits oxyaminés semblant trop encombrés stériquement). Quant au groupement TEMPO il a notamment pu être oxydé en cétone. Ainsi, des outils méthodologiques ont été développés lors de cette thèse, pour la difonctionnalisation oxydante d’énamides par des dérivés d’iode (III) hypervalent et en particulier, l’introduction d’halogénures et d’azoturesHypervalent iodine compounds such as (diacetoxyiodo)benzene (PIDA) are non-toxic and mild reagents that can behave in similar fashion to transition-metal complexes. Indeed, around the central iodine atom, ligands can be exchanged and then transferred through a formal reductive elimination. Following this strategy, halides can be used as ‘ligands’, in which case an umpolung of the salt can occur to give birth to electrophilic halogen species. Using LiBr, ethanol and PIDA, a variety of enamides underwent a regioselective ethoxybromination with high yields, short reaction time and good to excellent diastereoselectivity. One of the main interests of this reaction lies in the use of a cheap and widely available bromide salt (LiBr) to generate electrophilic halogen species by umpolung. Moreover, despite the oxidative nature of the reaction conditions, a wide scope of functional groups (olefins, esters, alcohols…) is tolerated. This reaction provides α-bromo-hemiaminals which are highly versatile synthons. For instance, various nucleophiles can be incorporated on the hemiaminal moeity and then engaged in further transformations. The development of an asymmetric variant of this transformation using chiral pool or chiral hypervalent iodine was unsucceful. This methodoly has been extended to the umpolung of other salts as chlorine with moderate to good yields (from 36% to 86%) and a moderate to very good diastereoselectivity (from 55/45 to 92/8) with a short reaction time (30 minutes). Mechanistic investigation for both reactions has been performed and an ionic parthway has been priviledge. The introduction of fluorine as an electrophile was not possible according to the litterature.Finally, the last halide, iodine can be tansfered and an ethoxyiodation reaction is under optimisation. Concerning the pseudo-halides, we devot a special attention to azides. Two methodologies has been set up : a diazidation reaction which yields are moderate (betwwen 20% and 52%), short reaction times (around 1 h) and moderate to good diastereoselectivity ratios (between 75/25 and 90/10) and an oxyamination reaction whiwh shows to be much more efficient with moderate to very high yields (from 31% to 95%), short reaction times (around 2 h), excellent diastereoselectivity ratio (superior to67/33). These two gathered reactions represent a useful tool for the introduction of a nitrogen. For the diazidation reaction, the intermediatories seem to be radicals whereas for the oxyamination reaction probably ionic species. . Thus, synthetic tools have been developped during this thesis for the difunctionnalisation of enamides by hypervalent iodine and particulary introduction of halides and azides
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Khan, Zulfiqar Ali. "Novel iodine mediated carbocyclisations and hypervalent iodine(III) reagents". Thesis, Cardiff University, 2010. http://orca.cf.ac.uk/54137/.
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The first chapter focuses on the introduction of iodine mediated carbocyclisations and their applications continue to present a stimulating challenge in target- and diversity-oriented synthesis. The second chapter discusses applications and brief literature overview about classical approaches towards the syntheses of indene derivatives. Herein the syntheses of 3-iodo-1 H-indene derivatives via iodonium-promoted 5-endo-dig carbocyclisation of 2-substituted ethynylmalonates as a key starting material are described. Within this study, we were able to show that the 3-iodo-1 H-indene can be used as a synthetic platform not only for the palladium chemistry but also as a catalyst for the in situ generation of [text unavailable] hypervalent iodine reagent. Additionally, 3-iodo-1 H-indene derivatives have the potential to perform asymmetric synthesis. Third chapter demonstrates tandem iodine mediated carboannulation of the stilbene malonate derivatives via either 5-exo- or 6-endo-trig mode under basic reagents with subsequent lactonisation to structurally complex indanes and tetrahydronaphthalenes with three new stereogenic centres. In the present study, a unique stereochemistry was observed in the case of tetrahydroindenofuranones and confirmed by single crystal X-ray analysis. These cyclisations proceed exclusively with the retention of configuration to form tetrahydroindenofuranones. Both the compounds formed as a single diastereomers as judged from their 1H and 13C NMR spectrum. In fourth chapter the synthesis of novel simplified analogues of IBA by oxidation of [text unavailable] diiodoacrylic acids are described. Additionally, the ligand exchange resulted in tosylate derivative. The new reagents have been utilized in various well established oxidative transformations with superior or similar reactivity as conventional hypervalent iodine(III) reagents.
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Brenet, Simon. "Nouvelle structure BINOL-Maléimide. Applications en catalyse d'oxydation asymétrique". Thesis, Grenoble, 2013. http://www.theses.fr/2013GRENV050/document.
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Les réactions asymétriques catalysées constituent une approche élégante au problème de l'introduction de centres stéréogène pour la synthèse de molécules complexes. Dans ce contexte, les oxydations sont notables de par la possibilité de créer en une seule étape à la fois le centre asymétrique ainsi que les fonctions dont les réactivités sont à la base des méthodologies de synthèse. La sélectivité d'un catalyseur est le plus souvent contrôlée par sa structure même. Notre groupe étudie les oxydations aérobies asymétriques par activation C-H par des analogues chiraux du N-hydroxyphtalimide (NHPI). Nous avons développé une nouvelle structure de catalyseur comportant un cœur BINOL-maléimide afin de dépasser les limitations intrinsèque des précédentes générations de catalyseurs. La première série n'a pas montré d'énantiosélectivité, cela nous a conduit a synthétiser une deuxième série dont les caractéristiques permettraient d'améliorer l'efficacité de ces catalyseurs d'oxydation aérobie asymétrique. Le développement d'un analogue portant deux iodes nous a conduit à étudier cette structure en tant que cœur de catalyseurs à base d'iode hypervalent. Nous avons analysé trois séries de ces catalyseurs pour l'oxytosylation de cétones prochirales et montré que notre structure est comparable avec celles présentées dans la littératureCatalysed asymmetric reactions are an elegant approach towards the synthesis of complex molecules for the controlled introduction of stereocenters. Within this field, oxidations are noteworthy since they allow to create in one step both the stereogenic elements and the moieties whose reactivities are the cornerstone of the methodologies of synthesis. The selectivity of a catalyst is most often controlled by its own structure. Our group has investigated catalysed asymmetric aerobic oxidations by C-H activation through the use of chiral analogues of N-hydroxyphtalimide (NHPI). We have developed a new structure of catalyst based upon a BINOL-fused maleimide core to circumvent the inherent limitations of previous catalysts generations. The first series showed no enantioselectivity and led us to synthesize a second series whose features are expected to improve the overall efficiency of those catalysts for asymmetric aerobic oxidations. The development of an analogue bearing two iodine moieties prompted us to study this structure as a core for chiral hypervalent organo-iodine(lll) catalysts. We have investigated three series of such catalysts for the asymmetric α-oxytosylation of prochiral ketones and showed that our structure is comparable with the ones found in the literature
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Peilleron, Laure. "Nouvelle approche synthétique vers des analogues de l'avibactam et cyclisations de N-alkoxyurées insaturées initiées par des réactifs d’iode(III) hypervalent". Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLS408/document.
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La situation très préoccupante due aux résistances antimicrobiennes incite les chimistes à concevoir de nouvelles molécules capables de lutter contre ces résistances. Les inhibiteurs de β-lactamases diazabicyclooctanes permettent de préserver l'arsenal thérapeutique actuel en restaurant l’activité des antibiotiques β-lactames. Ainsi, l'avibactam a été très récemment approuvé par la FDA et l'EMA en association avec la ceftazidime (une céphalosporine de 3ème génération) pour le traitement des infections sévères de bactéries Gram négatif. Ces composés se caractérisent par une structure bicyclique présentant un motif N-hydroxyurée cyclique qui est la clé de leur activité. Cependant, les méthodes permettant d’accéder facilement à ce type d'hétérocycles saturés, sont peu nombreuses. Dans le cadre de cette thèse, l'objectif était de développer une nouvelle approche synthétique permettant d’accéder à des analogues de l'avibactam. Pour cela, nous avons développé des cyclisations chimiosélectives, initiées par des réactifs d’iode(III) de N-alkoxyurées insaturées. Trois cyclisations différentes ont été optimisées et étudiées, fournissant des oxazolidinones oximes ou des N-oxyimidazolidinones à partir des mêmes substrats, selon des mécanismes distincts. Les différents modes de cyclisation peuvent être contrôlés grâce à l’association d’un réactif d'iode(III) et d'un sel d'halogénure ou de TEMPO, selon des conditions réactionnelles simples à mettre à œuvre. En parallèle, nous avons également réalisé la synthèse asymétrique d'un intermédiaire monocyclique clé, qui devrait conduire à des analogues de l'avibactam grâce à une nouvelle voie de synthèse utilisant la méthodologie de cyclisation développéeThe current dire situation of antimicrobial resistances urges synthetic chemists to design new molecules that can fight these resistances. Hence, the diazabicyclo-octanes β-lactamase inhibitors are of particular interest, as they can preserve the current therapeutic arsenal by restoring the activity of β-lactam antibiotics. Thus, avibactam was very recently approved by the FDA and the EMA in combination with ceftazidime (a 3rd generation cephalosporin antibiotic) for the treatment of severe Gram-negative bacteria infections. Structurally, these compounds are characterized by a bicyclic framework featuring a cyclic N-hydroxylated urea motif that is key to its activity. Yet, only few methods exist to easily access this singular type of saturated heterocycles. The aim of this project was to develop a new synthetic approach to acces a new range of avibactam analogues. For this, we developed chemoselective iodine(III)-mediated cyclizations of unsaturated N-alkoxyureas. We were able to optimize and study three different cyclizations that proceed through distinct mechanisms to yield oxazolidinone oximes, or N-oxyimidazolidinones from the same substrates. The different modes of cyclization can be triggered using a combination of the iodine(III) and a halide salt or TEMPO, under reaction conditions which are operationally simple and easily tunable. In parallel, we also devised asymmetric synthesis of a key monocyclic intermediate which should yield avibactam analogues, through a new synthetic route that relies on the methodology we developed
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Jia, Zhiyu. "Transformations promoted by the hypervalent iodine reagents". Doctoral thesis, Universitat Autònoma de Barcelona, 2014. http://hdl.handle.net/10803/134832.
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Malmedy, Florence. "Stereoselective transformations using chiral hypervalent iodine reagents". Thesis, Cardiff University, 2016. http://orca.cf.ac.uk/93576/.
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Hypervalent iodine (III) compounds are efficient, selective and environmentally friendly reagents. Due to their electrophilic nature and excellent leaving group ability, they can be used to mediate oxidative transformations; for example, the oxidation of sulfides to sulfoxides, the α-functionalisation of ketones, the dearomatisation of phenols, the functionalisation of alkenes and, more recently, the rearrangement of various substrates. In this thesis, the stereoselective rearrangement of propiophenone derivatives mediated by chiral hypervalent iodine reagents is described (Scheme i). A chiral lactate-based iodine (III) reagent was used to synthesise 2-arylpropionate derivatives with moderate to good yields and enantioselectivities. These compounds are highly attractive as they are direct precursors to Non-Steroidal Anti Inflammatory Drugs (NSAIDs). Scheme i. Rearrangement of propiophenone derivatives to 2-aryl-propionates. The cyclisation of malonate derivatives, mediated by hypervalent iodine reagents has also been investigated (Scheme ii). Several lactone derivatives were synthesised with this method, achieving moderate to good yields. Scheme ii. Cyclisation of malonate derivatives to synthesise functionalised lactones. Finally, the design of a new hypervalent iodine reagent is described (Figure i). After its synthesis, the pyridine-based reagent was tested in several model reactions, usually mediated by iodine (III) reagents. Its reactivity was similar to the one of other hypervalent iodine reagents. However, its ability to induce stereoselectivity to different products was quite poor. Figure i. Structure of the new hypervalent iodine reagent.
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Edmunds, J. J. "Novel fluorination reactions via hypervalent iodine reagents". Thesis, Imperial College London, 1988. http://hdl.handle.net/10044/1/47045.
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Romero, Segura Rafael Martín. "Development of hypervalent iodine(iii)-mediated chemical reactions". Doctoral thesis, Universitat Rovira i Virgili, 2017. http://hdl.handle.net/10803/402470.
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El iode hipervalent representa una poderosa eina per dur a terme diferent reaccions d’oxidació en condicions lliures de metalls. S’han realitzat estudis mecanístics que inclouen experiments de control físic-orgànics relatius a la diaminació intermolecular d’alquens mediats per iode(III) que han servit per a demostrar la veracitat dels càlculs computacionals realitzats prèviament.
Aquesta informació va proporcionar una visió crucial per al desenvolupament d’una nova reacció enantioselectiva de diaminació d’estirens catalitzada per iode(III). El disseny d’un nou catalitzador quiral de iode basat en l’ús de l’àcid làctic com a font econòmica de quiralitat representa la clau d’aquest assoliment. L’optimització del catalitzador implica l’increment de la densitat d’electrònica en el nucli de iode i un motiu d’amida secundària en la cadena lateral de lactat quiral. Entre els diferents oxidants terminals, el mCPBA ha resultat ser el més eficient conduint a bons rendiments i excel·lent enantioselectivitats (>99% ee). L’abast de la reacció comprèn alquens terminals i alquens interns dins del motiu de l’estirè.
En un estudi addicional, es va aconseguir la formació d’un nou enllaç carboni-bor. Així doncs, la borilació de sals de diariliodoni va ser possible després d’identificar el contra-anió del reactiu de diariliodoni més adequat. Mitjançant la generació in situ umpolung al centre de bor, la seva arilació per el reactiu hipervalent esdevé possible. Amb aquest fi, diferent acetats de diariliodoni van ser sintetitzats, demostrant la gran aplicabilitat d’aquest nou mètode respecte al grup aromàtic transferible. Aquest mètode s’afegeix a l’escàs nombre de reaccions de borilació en condicions lliures de metalls.Los reactivos de iodo hipervalente representan una herramienta muy poderosa para la realización de diferentes oxidaciones libres de metal. Se llevaron a cabo estudios mecanísticos incluyendo experimentos físico-orgánicos de control respecto a la diaminación intermolecular de alquenos, demostrando la veracidad de los cálculos DFT previamente realizados. Esta información resultó crucial para el desarrollo de una pionera diaminación enantioselectiva de estirenos catalizada por iodo(III). Uno de los mayores logros es el diseño de un nuevo catalizador de iodo quiral basado en el ácido láctico como fuente económica de información estereoquímica. La optimización del catalizador incluye un aumento crucial de electrondensidad en el núcleo de iodo y la presencia del grupo amida en la cadena de lactato quiral. Entre los diferentes oxidantes terminales probados, mCPBA resultó ser el más eficiente, dando buenos rendimientos y una enantioselectividad sin precedentes, siendo ésta siempre superior al 90% ee. Esta reacción puede extenderse a alquenos terminales e internos que contengan la estructura de estireno. Este logro representa uno de los resultados más avanzados en la diaminación asimétrica de alquenos. En un estudio adicional, se consiguió una nueva formación de enlaces carbono-boro. Aquí, la borilación de sales de diariliodonio fue posible tras la identificación de un contraión apropiado en el reactivo de diariliodonio. Gracias a la generación in situ de un umpolung en el centro de boro, su arilación por el reactivo hipervalente es posible. Con esta finalidad, se sintetizaron diferentes acetatos de diariliodonio y se demostró la gran aplicabilidad de esta metodología en la transferencia de grupos aromáticos. Este protocolo representa uno de los pocos procesos económicos de borilación en ausencia de metal.
Hypervalent iodine(III) reagents represent a powerful tool for the realisation of different metal-free oxidation reactions. Mechanistic studies including physical-organic control experiments concerning the oxidative iodine(III)-mediated intermolecular diamination of alkens were carried out, demonstrating the veracity of previous DFT calculations. This information provided crucial insight for the development of a pioneering iodine(III)-catalysed enantioselective diamination of styrenes. The design of a novel chiral iodine catalyst based on lactic acid as economic chiral information source represents the key accomplishment. Catalyst optimisation involves a crucial electrondensity enhancement at the iodine core and a secondary amide motive in the chiral lactate side chain. Among different terminal oxidants, conventional mCPBA emerged as the most efficient one leading to good yields and unprecedented enantioselectivities of above 90% ee. The scope of the reaction comprises terminal and internal alkenes within the styrene motif. It represents the state of the art in asymmetric diamination of alkenes. In an additional study, a novel carbon-boron bond formation was accomplished. Here, borylation of diaryliodonium salts was encountered feasible upon identification of a suitable counterion in the diaryliodonium reagent. By generating an in situ umpolung at the boron centre, its arylation by the hypervalent reagent becomes viable. To this end, different diaryliodonium acetates were synthesised, thereby successfully demonstrating a broad applicability of this new methodology regarding the transferable aromatic group. This protocol adds to the still scarce number of economic borylation reactions under metal-free conditions.
Livros sobre o assunto "Iodure hypervalent"
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Zhdankin, Viktor V. Hypervalent Iodine Chemistry. Chichester, UK: John Wiley & Sons Ltd, 2013. http://dx.doi.org/10.1002/9781118341155.
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Wirth, Thomas, ed. Hypervalent Iodine Chemistry. Cham: Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-33733-3.
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Wirth, Thomas, ed. Hypervalent Iodine Chemistry. Berlin, Heidelberg: Springer Berlin Heidelberg, 2002. http://dx.doi.org/10.1007/3-540-46114-0.
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Andrews, Ian Philip. Hypervalent iodine oxidations of substituted pyridines. Norwich: University of East Anglia, 1992.
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McLaren, Lee. Synthetic applications of hypervalent iodine reagents: Total synthesis of aranorosin. Norwich: Universityof East Anglia, 1994.
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Koyuncu, Demet. Functional group oxidations using sodium perborate and hypervalent iodine reagents. Norwich: Universityof East Anglia, 1992.
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Wirth, Thomas. Hypervalent Iodine Chemistry. Springer, 2016.
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Wirth, Thomas. Hypervalent Iodine Chemistry. Springer International Publishing AG, 2018.
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Wirth, Thomas. Hypervalent Iodine Chemistry. Springer London, Limited, 2016.
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Katritzky, Alan R., O. Meth-Cohn, A. Varvoglis e C. S. Rees. Hypervalent Iodine in Organic Synthesis. Elsevier Science & Technology Books, 1996.
Encontre o texto completo da fonteCapítulos de livros sobre o assunto "Iodure hypervalent"
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Dohi, Toshifumi, e Yasuyuki Kita. "Hypervalent Iodine". In Iodine Chemistry and Applications, 103–57. Hoboken, NJ: John Wiley & Sons, Inc, 2014. http://dx.doi.org/10.1002/9781118909911.ch7.
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Kumar, Ravi, e Thomas Wirth. "Asymmetric Synthesis with Hypervalent Iodine Reagents". In Hypervalent Iodine Chemistry, 243–61. Cham: Springer International Publishing, 2015. http://dx.doi.org/10.1007/128_2015_639.
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Murarka, Sandip, e Andrey P. Antonchick. "Oxidative Heterocycle Formation Using Hypervalent Iodine(III) Reagents". In Hypervalent Iodine Chemistry, 75–104. Cham: Springer International Publishing, 2015. http://dx.doi.org/10.1007/128_2015_647.
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Maertens, Gaëtan, e Sylvain Canesi. "Rearrangements Induced by Hypervalent Iodine". In Hypervalent Iodine Chemistry, 223–41. Cham: Springer International Publishing, 2015. http://dx.doi.org/10.1007/128_2015_657.
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Früh, Natalja, Julie Charpentier e Antonio Togni. "Iodanes as Trifluoromethylation Reagents". In Hypervalent Iodine Chemistry, 167–86. Cham: Springer International Publishing, 2015. http://dx.doi.org/10.1007/128_2015_658.
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Waser, Jerome. "Alkynylation with Hypervalent Iodine Reagents". In Hypervalent Iodine Chemistry, 187–222. Cham: Springer International Publishing, 2015. http://dx.doi.org/10.1007/128_2015_660.
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Olofsson, Berit. "Arylation with Diaryliodonium Salts". In Hypervalent Iodine Chemistry, 135–66. Cham: Springer International Publishing, 2015. http://dx.doi.org/10.1007/128_2015_661.
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Muñiz, Kilian. "Aminations with Hypervalent Iodine". In Hypervalent Iodine Chemistry, 105–33. Cham: Springer International Publishing, 2015. http://dx.doi.org/10.1007/128_2015_663.
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Protasiewicz, John D. "Organoiodine(III) Reagents as Active Participants and Ligands in Transition Metal-Catalyzed Reactions: Iodosylarenes and (Imino)iodoarenes". In Hypervalent Iodine Chemistry, 263–88. Cham: Springer International Publishing, 2015. http://dx.doi.org/10.1007/128_2015_664.
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Quideau, Stéphane, Laurent Pouységu, Philippe A. Peixoto e Denis Deffieux. "Phenol Dearomatization with Hypervalent Iodine Reagents". In Hypervalent Iodine Chemistry, 25–74. Cham: Springer International Publishing, 2016. http://dx.doi.org/10.1007/128_2015_665.
Texto completo da fonteTrabalhos de conferências sobre o assunto "Iodure hypervalent"
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Moriarty, Robert M., Jaffar S. Khosrowshahi e Tomasz Dalecki. "Hypervalent Iodine Iodinative Decarboxylation Of Cubyl And Homocubyl Carboxylic Acids". In 1988 Los Angeles Symposium--O-E/LASE '88, editado por Joseph Flanagan. SPIE, 1988. http://dx.doi.org/10.1117/12.943749.
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Utaka, Aline, Lívia N. Cavalcanti e Luiz F. Silva Jr. "Electrophilic alkynylation of ketones using hypervalent iodine reagent: a new approach to quaternary carbon formation". In 15th Brazilian Meeting on Organic Synthesis. São Paulo: Editora Edgard Blücher, 2013. http://dx.doi.org/10.5151/chempro-15bmos-bmos2013_201391510568.
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Dávila Rodríguez, Izaskun. "Searching for new applications of the hypervalent iodine reagents in the construction of nitrogen containing compounds". In MOL2NET 2016, International Conference on Multidisciplinary Sciences, 2nd edition. Basel, Switzerland: MDPI, 2016. http://dx.doi.org/10.3390/mol2net-02-h007.
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