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Palladium(II)-Catalyzed Oxidative Carbocyclization : Stereoselective Formation of C–C and C–B BondsJiang, Tuo January 2014 (has links)
Transition metal catalysis has emerged as one of the most versatile methods for the selective formation of carbon–carbon and carbon–heteroatom bonds. In particular, oxidative carbon–carbon bond forming reactions have been widely studied due to their atom economic feature. This thesis has been focused on the development of new palladium(II)-catalyzed carbocyclization reactions under oxidative conditions. The first part of the thesis describes the palladium(II)-catalyzed oxidative carbocyclization-borylation and -arylation of enallenes. In these reactions, the (σ-alkyl)palladium(II) intermediate, which was shown previously to undergo β-hydride elimination, could be trapped in situ by organoboron reagents (B2pin2 and arylboronic acids) to form new carbon–boron and carbon–carbon bonds. Through these two protocols, a range of borylated and arylated carbocycles were obtained as single diastereomers in high yields. The second part deals with a palladium(II)-catalyzed oxidative diarylative carbocyclization of enynes. The reaction was proposed to start with a syn-arylpalladation of an alkyne, followed by insertion of the coordinated alkene. Subsequent arylation afforded a series of valuable diarylated tetrahydrofuran and tetrahydropyran products. The final part of the thesis advances the previously developed palladium(II)-catalyzed oxidative carbocyclization-borylation of enallenes in an enantioselective manner. C2-symmetric chiral phosphoric acids were used as the novel co-catalyst to trigger the enantioselective formation of intramolecular carbon–carbon bonds. By using this chiral anion strategy, a number of enallenes were converted to the borylated carbocycles with high to excellent enantioselectivity. / <p>At the time of the doctoral defense, the following paper was unpublished and had a status as follows: Paper 4: Manuscript.</p>
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Directed C-H borylation for the synthesis of fused and ladder type conjugated oligomers and polymersCrossley, Daniel January 2016 (has links)
The synthesis, photophysical and electronic properties of a series of novel boron containing fused and ladder type donor-acceptor (D-A) oligomers and polymers are reported. The synthesis was achieved through coordination of the basic functionality of the ubiquitous benzothiadiazole acceptor unit onto a boron Lewis acid followed by an electrophilic aromatic borylation resulting in the formation of fused and ladder type structures (termed borylative fusion). The novel C,N-chelated borane structures disclosed herein are a new member of a large family of tetra-coordinate organoboron compounds that are used for the construction of highly emissive materials. Upon borylation large bathochromic shifts in the absorption and fluorescence spectra were observed, DFT and cyclic voltammetry demonstrate that this is a result of a significant reduction of the LUMO energy levels whist the HOMO energy levels remains relatively unperturbed. These large bathochromic shifts lead to materials that show far red/NIR emission in the solid state with absolute quantum yields of up to 44%. Furthermore, the frontier molecular orbital energy levels of these fused structures can be modulated through judicious selection of the exocyclic boron substituents. These novel borocycles also proved stable to a range of cross-coupling conditions which facilitated further modulation of the frontier molecular orbitals and emissive properties. Borylative fusion was also applicable to D-A conjugated polymers, this represents a facile post-polymerisation functionalisation that is an effective method of modulating the photophysical properties of D-A conjugated polymers. Solution processed OLEDs with far red/NIR electroluminescence (EL) were fabricated from these materials. These devices showed good external quantum efficiency values (EQE) for the far red/NIR region of the electromagnetic spectrum (EQE > 0.4 % for maximum EL > 700 nm).
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Synthèse stéréosélective d'aminoacides boronatés et silylés pour le piégeage de fluorures, à visée imagerie médicale / Stereoselective synthesis of boronated and silylated amino acids for fluorine trapping, referred to medical imagingAudi, Hassib 18 December 2012 (has links)
La synthèse stéréosélective d'une nouvelle classe d'amino acides boronatés est réalisée par réaction de Wittig, puis borylation catalysée par un complexe d'iridium. Des amino esters portant un noyau aromatique en position δ de la chaîne latérale, sont tout d'abord préparés par réaction de Wittig d'un sel de phosphonium dérivé d'amino acide avec l'aldéhyde aromatique correspondant, puis estérification et hydrogénation. La borylation de ces amino esters avec le bis(pinacolato)diborane (B2Pin2) en présence d'un complexe d'iridium comme catalyseur, conduit aux dérivés correspondants boronatés avec des rendements atteignant 74% . Enfin, des dérivés iodés ou trifluoroboratés sont facilement obtenus à partir des amino acides boronatés, par réaction avec Nal ou avec KHF2. L'hydrolyse des trifluoroborates d'amino acides en solution tampon a été étudiée par RMN 19F. Dans le cas des amino esters difluorophényle et thiophényle, ces composés montrent une très bonne stabilité à l'hydrolyse. D'un autre côté, la synthèse stéréosélective d'amino acides silylés est également obtenue par réaction de Wittig du sel de phosphonium dérivé d'amino acide avec le 4-di-t-butylsilanobenzaldéhyde. L'amino acide silylé a été utilisé pour la préparation d'un dipeptide avec un rendement de 80%, puis son dérivé fluorosilane sans racémisation, par réaction avec KF. Le dipeptide fluorosilylé obtenu montre une excellente stabilité à l'hydrolyse après 10 jours. Finalement, la méthode de synthèse mise au point, se révèle très efficace pour la préparation d'amino acides boronatés et silylés, et pour leur application au marquage par l'iode ou les fluorures / The stereoselective synthesis of new boronato amino acid derivatives, using Wittig and C-H iridium-catalyzed borylation as key step reactions, is described. Firstly, the synthesis of amino ester precursors bearing an aromatic moiety in -position of the lateral chain, was achieved by Wittig reaction of a phosphonium salt derived from amino acid with the corresponding aromatic aldehyde, then esterification and hydrogenation. The reaction of the amino esters with the bis(pinacolato)diborane reagent (B2Pin2) in presence of an iridium complex as catalyst, leads to the corresponding boronato derivatives in yields up to 74 %. Finally, the iodo- or trifluoroborato derivatives were easily prepared from the boronato amino acid by reaction either with NaI or with KHF2. The hydrolysis of the trifluoroborato amino acid derivatives was studied in buffer solution using 19F NMR monitoring. In the case of the difluorophenyl and thiophenyl amino esters, the corresponding trifluoroborates derivatives show good to excellent stability toward hydrolysis. In addition, the stereoselective synthesis of silano amino acid has been developped by Wittig reaction of the phosphonium salt derived from amino acid with the 4-di-t-butylsilanobenzaldehyde. The silano amino acid was used to prepare a dipeptide with 80% yield, and the corresponding fluorosilane derivative without racemization, by reaction with KF. The hydrolysis of the fluorosilylated dipeptide in aqueous media shows an excellent stability, up to 10 days. Finally, this stereoselective synthesis of hetero substituted amino acids, offers a promising tool for the application of the boronated and silyled derivatives to the fluoride labeling
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Production of New Carbon-Heteroatom Bonds Induced by Visible LightHerrera Luna, Jorge Carlos 05 January 2023 (has links)
[ES] En la presente tesis doctoral se describen metodologías novedosas, simples y rápidas con luz visible para producir compuestos con nuevos enlaces C-heteroátomo como C-B, C-P y C-S que representan estructuras valiosas en la síntesis orgánica moderna. La luz visible se emplea como fuente de energía más suave y sostenible que la tradicional (energía térmica). Por otro lado, también se han empleado nanorreactores espaciales como las redes de gel viscoelástico mediante enfoques 'ascendentes' para mejorar diferentes procesos en comparación con la disolución, en términos de cinética, selectividad o procesabilidad.
Por lo tanto, el Capítulo 3 describe un procedimiento novedoso, directo y rápido para producir tiofenos que contienen boro empleando luz visible en disolución anaeróbica sin el uso de ningún fotocatalizador externo. Este estudio se ha ampliado a la borilación de haluros de heteroareno comerciales en condiciones aeróbicas en un nanorreactor de gel fácil de usar (Capítulo 4). La red de gel proporciona un microambiente estabilizador adecuado para soportar una amplia gama de sustratos, incluidos los ésteres de boronato de furano, tiofeno, selenofeno y de pirrol.
El Capítulo 5 se centra en una nueva estrategia para lograr una fosforilación aeróbica eficiente de heteroarenos de cinco miembros mediante catálisis fotorredox dicromática en un nanorreactor basado en gel. La metodología, que opera mediante un mecanismo de transferencia de electrones fotoinducida consecutiva (ConPET), se ha aplicado con éxito a la síntesis sencilla y limpia de varios fosfonatos de heteroareno diferentes (furano, tiofeno, selenofeno, pirrol, oxazol o tioxazol), extendiéndose a la etapa tardía de la fosforilación del anticoagulante rivaroxabán. Por último, el Capítulo 6 muestra una tiolación (formación enlaces C-S) simple y efectiva, libre de metales, de haluros de heteroareno comerciales usando luz visible. Los resultados experimentales son consistentes con una reacción basada en un complejo aceptor-donador de electrones (EDA) entre una alquilamina y el haluro de heteroareno. El mecanismo del proceso se ha demostrado mediante estudios espectroscópicos, mientras que la robustez se ha demostrado mediante experimentos a escala de gramo y derivatización de última etapa. / [CA] En la present tesi doctoral es descriuen metodologies noves, simples i ràpides amb llum visible per a produir compostos amb nous enllaços C-heteroàtom com C-B, C-P i C-S que representen estructures valuoses en la síntesi orgànica moderna. La llum visible s'utilitza com a font d'energia mes suau i sostenible que la tradicional (energia tèrmica). D'altra banda, també s'han emprat nanorreactors espacials com les xarxes de gel viscoelàstic mitjançant enfocaments 'ascendents' per a millorar diferents processos en comparació amb la dissolució, en termes de cinètica, selectivitat o procesabilitat. Per tant, el Capítol 3 descriu un procediment nou, directe i ràpid per a produir tiofens que contenen bor emprant llum visible en dissolució anaeròbica sense l'ús de cap fotocatalitzador extern. Aquest estudi s'ha ampliat a la borilació d'halurs d'heteroaré comercials en condicions aeròbiques en un nanorreactor de gel fàcil d'usar (Capítol 4). La xarxa de gel proporciona un microambient estabilitzador adequat per a suportar una àmplia gamma de substrats, inclosos els èsters de boronat de furan, tiofé, selenofé i de pirrol. El Capítol 5 se centra en una nova estratègia per a aconseguir una fosforilació aeròbica eficient de heteroarens de cinc membres mitjançant catàlisis fotorredox dicromàtica en un nanorreactor basat en gel. La metodologia, que opera mitjançant un mecanisme de transferència d'electrons fotoinducida consecutiva (ConPET), s'ha aplicat amb èxit a la síntesi senzilla i neta de diversos fosfonats d'heteroaré diferents (furan, tiofé, selenofé, pirrol, oxazol o tioxazol), estenent-se a l'etapa tardana de la fosforilació de l'anticoagulant rivaroxabán. Finalment, el Capítol 6 mostra una tiolació (formació d'enllaços C-S) simple i efectiva, lliure de metalls, d'halurs d'heteroaré comercials usant llum visible. Els resultats experimentals són consistents amb una reacció basada en un complex acceptor-donador d'electrons (EDA) entre una alquilamina i l'halur d'heteroaré. El mecanisme del procés s'ha demostrat mitjançant estudis espectroscòpics, mentre que la robustesa s'ha demostrat mitjançant experiments a escala de gram i derivatització d'última etapa. / [EN] This thesis doctoral describes novel, simple, and rapid methodologies using visible light to produce compounds with new C-heteroatom bonds such as C-B, C-P and C-S that represent valuable scaffolds in modern organic synthesis. The employment of visible light as energy source highlights the concepts of green and sustainable chemistry considering its mild, safe, and eco-friendly advantages. On the other hand, spatially nanoreactors such as viscoelastic gel networks by 'bottom-up' approaches to improve different processes in comparison to solution, in terms of kinetics, selectivity or processability have been also developed.
Thus, Chapter 3 describes a novel, straightforward, and fast procedure to produce boron-containing thiophenes employing visible light in anaerobic solution. Interestingly, the process does not require the use of any external photocatalyst. This study has been extended to the borylation of commercially available heteroarene halides under aerobic conditions in an easy-to-use gel nanoreactor (Chapter 4). The gel network provides an adequate stabilizing microenvironment to support wide substrate scope, including furan, thiophene, selenophene, and pyrrole boronate esters.
Chapter 5 focus on a new strategy to achieve efficient aerobic phosphorylation of five-membered heteraroenes using dichromatic photoredox catalysis in a gel-based nanoreactor. The methodology, which operates by a consecutive photoinduced electron transfer (ConPET) mechanism, has been successfully applied to the straightforward and clean synthesis of a number of different heteroarene (furan, thiophene, selenophene, pyrrole, oxazole, or thioxazole) phosphonates, extending to the late-stage phosphonylation of the anticoagulant rivaroxaban.
Lastly, regarding the construction of new C-S bonds, Chapter 6 shows a simple and effective metal-free thiolation of commercial heteroarene halides using visible light. The experimental results are consistent with the reaction taking place from an electron donor-acceptor (EDA) complex between an alkylamine and the heteroarene halide. Mechanistic aspects of the whole process have been demonstrated by spectroscopic measurements whereas the strength of this novel method has been proven by gram-scale experiment and late-stage derivatization. / Herrera Luna, JC. (2022). Production of New Carbon-Heteroatom Bonds Induced by Visible Light [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/191051
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Transition metal-catalyzed allylic and vinylic functionalization : Method development and mechanistic investigationsLarsson, Johanna M. January 2013 (has links)
The use of small molecule building blocks in, for example, pharmaceutical research and new material development, creates a need for new and improved organic synthesis methods. The use of transition metals as mediators and catalysts opens up new reaction pathways that have made the synthesis of completely new compounds possible as well as greatly improved the synthetic routes to known compounds. Herein, the development of new metal-mediated and catalyzed reactions for construction of vinylic and allylic carbon-carbon and carbon-heteroatom bonds is described. The use of iodonium salts as coupling partners in Pd-catalyzed Heck type reactions with alkenes is shown to improve the current substrate scope. Results from a mechanistic study indicate that the reaction proceeds via high oxidation state palladium intermediates. The use of IIII reagents is also believed to facilitate a PdII/PdIV catalytic cycle in allylic silylation of alkenes using (SiMe3)2, which, to the best of our knowledge, is the first method developed for metal-catalyzed allylic C-H silylation. The same silyl-source, (SiMe3)2, has previously been used in a Pd-catalyzed allylic substitution reaction in which allylic silanes are formed from allylic alcohols. A detailed mechanistic investigation of this reaction is described in which by-products as well as intermediates, including the resting state of the catalyst, are identified using 1H, 11B, 19F and 29Si NMR spectroscopy. Kinetic experiments are performed that give information about the turn-over limiting step and the mechanism of the analogous borylation using B2pin2 is also investigated. Insights from this study further made it possible to improve the stereoselectivity of this reaction. Additionally, a new method for Cu-mediated trifluoromethylation of allylic halides is presented in which linear products are formed exclusively from both linear and branched allylic substrates at room temperature. Identification of allylic fluorides as by-products during the reaction also led to the development of a similar Cu-mediated reaction for the fluorination of allylic halides. / <p>At the time of the doctoral defense, the following paper was unpublished and had a status as follows: Paper 4: Manuscript.</p>
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Étude de nouvelles méthodologies d'arylation directe en séries azole et pyridine : Application à la synthèse de coeurs de thiopeptides antibiotiques de la série dLassalas, Pierrik 11 December 2012 (has links) (PDF)
Face à l'apparition grandissante de souches bactériennes multi-résistantes à l'arsenal d'antibiotiques actuels, les thiopeptides antibiotiques, bien que connus depuis plus de 60 ans, suscitent actuellement un fort regain d'intérêt. En effet, cette classe de molécules présente une forte activité antibiotique contre des souches bactériennes résistantes et multirésistantes, et met en œuvre deux modes d'inhibition originaux de la synthèse protéique encore inexploités en thérapie antibiotique humaine. Leur développement pharmacologique est en particulier freiné par la difficulté de préparation de ces molécules très complexes. L'élaboration d'une stratégie innovante de synthèse de la partie la plus complexe de ces molécules, le cœur hétérocyclique est étudiée dans ce travail. Cette approche repose sur l'étude et la valorisation de nouvelles méthodologies de fonctionnalisation directe des liaisons C-H et C-X de mono- et bis-thiazoles avec une large gamme d'hétéroaromatiques. Sa viabilité est démontrée par la préparation du cœur hétérocyclique commun aux amythiamicines.
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Étude de nouvelles méthodologies d’arylation directe en séries azole et pyridine : Application à la synthèse de coeurs de thiopeptides antibiotiques de la série d / Development of new C-H and C-X direct arylation methodologies in thiazole and pyridine series : application to the synthesis of the heterocyclic core of thiopeptides antibiotics in the d seriesLassalas, Pierrik 11 December 2012 (has links)
Face à l’apparition grandissante de souches bactériennes multi-résistantes à l’arsenal d’antibiotiques actuels, les thiopeptides antibiotiques, bien que connus depuis plus de 60 ans, suscitent actuellement un fort regain d’intérêt. En effet, cette classe de molécules présente une forte activité antibiotique contre des souches bactériennes résistantes et multirésistantes, et met en œuvre deux modes d’inhibition originaux de la synthèse protéique encore inexploités en thérapie antibiotique humaine. Leur développement pharmacologique est en particulier freiné par la difficulté de préparation de ces molécules très complexes. L'élaboration d'une stratégie innovante de synthèse de la partie la plus complexe de ces molécules, le cœur hétérocyclique est étudiée dans ce travail. Cette approche repose sur l'étude et la valorisation de nouvelles méthodologies de fonctionnalisation directe des liaisons C-H et C-X de mono- et bis-thiazoles avec une large gamme d’hétéroaromatiques. Sa viabilité est démontrée par la préparation du cœur hétérocyclique commun aux amythiamicines. / Due to the emergence of multiresistant bacterial strains to standard antibacterial treatments, thiopeptides antibiotics are actually highly considered, though they are known for 60 years. They show an excellent antibiotic activity against multiresistant bacterial strains, and implement two originals inhibition mechanisms of protein synthesis, still unemployed in human therapy. However, the difficulty to prepare these complex macromolecules limits their pharmacological development. The development of a new strategy to synthetize the most complicated part of these macromolecules, their heterocyclic core, is studied here in. This approach is based on the study and the exploitation of novel direct C-H and C-X transition-metal-catalyzed couplings of mono- and bithiazoles units with a broad panel of heteroaromatics. Its viability is here demonstrated trough the multi-step synthesis of the common heterocyclic core of amythiamicins.
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Amine-Boranes: Synthesis and ApplicationsHenry J Hamann (10730742) 30 April 2021 (has links)
Reported herein is a brief summary of the history,
properties, and applications of amine-boranes. The past methods devised for
their preparation are described and the routes used to produce the compounds
used in the work presented here are detailed. Building on prior synthetic
approaches to amine-boranes, a new carbon dioxide mediated synthesis is
presented. Proceeding through a monoacyloxyborane intermediate, the borane
complexes of ammonia, primary, secondary, tertiary, and heteroaromatic amine
are provided in 53-99% yields. Utilizing the amine-boranes obtained from the
methods described, two divergent methods for direct amidation are introduced.
The first uses amine-boranes as dual-purpose reagents, where the carboxylic
acid is first activated by the borane moiety to form a triacyloxyborane-amine
complex. This allows the delivery of the coordinated amine to form the amide
products. A series of primary, secondary, and tertiary amides were prepared in 55-99% yields using this protocol, which
displays a broad functional group tolerance. Extended from this dual-purpose
methodology, a catalytic amidation is described. Utilizing ammonia-borane as a
substoichiometric (10%) catalyst, a series of secondary and tertiary amide are
prepared directly from carboxylic acids and amines in 59-99% yields, including
amines containing typically borane reactive functionalities including alcohols,
thiols, and alkenes. Amine-boranes are additionally used in two borylation
methodologies. By reaction with <i>n</i>-butyl lithium, the amine-boranes are
converted to the corresponding lithium aminoborohydrides, which upon reaction
with a terminal alkyne provides the alkynyl borane-amine complexes in 65-98%
yields. This process is compatible with both alkenes and internal alkynes, as
well as a range of aprotic functionalities. A new strategy for aminoborane
synthesis is also described and applied to the borylation of haloarenes.
Activation of a series of amine-boranes with iodine produces the iodinated
amine-borane, which undergoes dehydrohalogenation with an appropriate base to
produce either monomeric or dimeric aminoboranes. Several aminoboranes were
synthesized exclusively as the monomeric species, which due to their greater
reactivity, were used directly in the synthesis of a series of aryl boronates
in 65-99% yields.
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Novel methodology for the synthesis of ¹³C-Labelled phenols and its application to the total synthesis of polyphenolsMarshall, Laura J. January 2010 (has links)
The base-catalysed reaction of 4H-pyran-4-one with a range of nucleophiles, namely diethyl malonate, ethyl acetoacetate, nitromethane, acetylacetone and ethyl cyanoacetate, was developed as a reliable, high yielding method for the preparation of para-substituted phenols. The methodology was extended to include the use of the substituted pyranones, maltol, 2,6-dimethyl-4H-pyran-4-one and diethyl chelidonate. Reactions were studied using conventional heating methods and microwave irradiation. Microwave irradiation had definite beneficial effects, with improved yields, reduced reaction times and cleaner reaction profiles. The potential of this methodology was examined for the regioselective placement of ¹³C-atoms into benzene rings using ¹³C-labelled nucleophiles or ¹³C-labelled 4H-pyran-4-ones. [3,5-13C₂]4H-Pyran-4-one and [2,6-13C₂]4H-pyran-4-one were prepared from various ¹³C-labelled versions of triethyl orthoformate and acetone. This methodology was applied to the synthesis of [1,3,5-¹³C₃]gallic acid, via the base-catalysed reaction of [3,5-¹³C₂]4H-pyran-4-one with diethyl [2-¹³C]malonate, followed by subsequent transformations to yield [1,3,5-¹³C₃]gallic acid. The preparation of [2-¹³C]phloroglucinol was carried out via [2-¹³C]resorcinol, with regioselective placement of a single ¹³C-atom into the aromatic ring. This was accomplished from non-aromatic precursors, with the source of the ¹³C-atom being [¹³C]methyl iodide. The key step in this synthesis was the introduction of the third hydroxyl group, which was achieved using a modified iridium-catalysed C-H activation/borylation/oxidation procedure. The scope of an existing C-H activation/borylation reaction was modified and expanded to include a range of protected resorcinol derivatives. A catalyst system was developed which allowed high conversion to the intermediate arylboronic acids, followed by oxidation using aqueous Oxone® to yield the corresponding phenols. Finally, to demonstrate the potential of these new methods for application in the synthesis of isotopically labelled natural products and polyphenols, the syntheses of ¹³C-labelled anthocyanins were studied. A route was developed that could be applied to the synthesis of either cyanidin-3-glucoside or delphinidin-3-glucoside. Only the final coupling/cyclisation step to yield the desired anthocyanin targets remains to be carried out.
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Synthese und Reaktivität von Rhodium(I)-Boryl-Komplexen und ihre Verwendung als Katalysatoren in BorylierungsreaktionenKalläne, Sabrina 12 March 2015 (has links)
Da Boryl-Komplexe als Schlüsselintermediate in Borylierungsreaktionen betrachtet werden, gilt Ihnen ein großes experimentelles und theoretisches Interesse. Das Ziel der vorliegenden Dissertation ist daher die Darstellung hoch reaktiver 16 VE-Rhodium(I)-Boryl-Komplexe. Der Fokus der Arbeit liegt auf der Untersuchung ihres Reaktionsverhaltens sowie ihrer katalytischen Aktivität in Reaktionen, die die Bildung neuer Bor-Element-Bindungen zur Folge haben und somit z. B. die Darstellung von Boronsäureestern als wertvolle Synthesebausteine ermöglichen. In dieser Arbeit wird neben der erfolgreichen Darstellung mehrerer Rhodium(I)-Boryl-Komplexe exemplarisch das Reaktionsverhalten des Pinacolatoboryl-Komplexes gegenüber substituierten (Hetero-)Aromaten, Aminen sowie ungesättigten Verbindungen beschrieben. Die Untersuchungen zeigen, dass der Boryl-Komplex mit Aromaten wie Phenyltrifluormethylsulfid oder fluorierten Benzolderivaten chemo- und regioselektiv unter Aktivierung von C-H-Bindungen reagiert und dass mit Aminen wie Anilin hingegen gezielt die N-H-Bindung aktiviert wird. Darüber hinaus erwies sich der Boryl-Komplex als effizienter Katalysator für C-H- und N-H-Borylierungsreaktionen und ist somit zur katalytischen Darstellung borylierter Verbindungen geeignet. Weitere Studien mit Verbindungen, die eine C=X-Bindung (X = O, N, C, S) besitzen, wie Ketone und Imine sowie Stilben und Thioharnstoff zeigen die ausgeprägte Neigung des Rhodium(I)-Boryl-Komplexes, initial unter Insertion der ungesättigten Verbindung in die Rhodium-Bor-Bindung zu reagieren. Diese Beobachtungen können wichtige Informationen über die Teilschritte eines Katalyseprozesses geben. Besonders bemerkenswert ist die Reaktivität des Boryl-Komplexes gegenüber Kohlenstoffdioxid und Schwefelkohlenstoff, die in der Spaltung der stabilen C=X-Bindung (X = O, S) resultiert. Insgesamt verdeutlicht das hier beschriebene breite Reaktivitätsspektrum der Rhodium(I)-Boryl-Komplexe die Relevanz dieses Forschungsgebiets. / Since boryl complexes are regarded as key intermediates in borylation reactions, there is a high experimental and theoretical interest. Therefore, the aim of this dissertation is the synthesis of highly reactive 16 VE rhodium(I) boryl complexes. Moreover, the thesis focuses on their reactivity as well as their catalytic activity in reactions, which afford new boron-element bonds and, thus, enable for example the synthesis of boronic esters as useful building blocks. Herein, in addition to the successful synthesis and characterization of several rhodium(I) boryl complexes, the reactivity of the pinacolato boryl complex towards substituted (hetero)arenes, amines and unsaturated substrates is described. The studies reveal that the treatment of the boryl complex with aromatics like phenyltrifluoromethyl sulfid or fluorinated benzene derivatives leads chemo- and regioselectively to C-H bond activation reactions and that in contrast, with amines like aniline the N-H bond is exclusively activated. Furthermore, the boryl complex turned out to be an efficient catalyst for C-H and N-H borylation reactions and yields borylated compounds in a catalytic way. Further investigations with reagents containing a C=X bond (X = O, N, C, S) like ketones and imines as well as stilbene and thiourea show the pronounced tendency of the rhodium(I) boryl complex to react initially via insertion of the unsaturated unit into the rhodium-boron bond. These results might give a deeper insight into the mechanism of catalytic processes. The remarkable reactivity of the boryl complex towards carbon dioxide and carbon disulfide is reported, too, which result in the cleavage of the thermodynamic stable C=X double bonds (X = O, S). Overall, the here shown wide range of reactivity of rhodium(I) boryl complexes demonstrates the relevance of this research topic.
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