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Auswahl der wissenschaftlichen Literatur zum Thema „Asymmetric photocatalysis“
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Zeitschriftenartikel zum Thema "Asymmetric photocatalysis"
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Kang, Xing, Xiaowei Wu, Xing Han, Chen Yuan, Yan Liu und Yong Cui. „Rational synthesis of interpenetrated 3D covalent organic frameworks for asymmetric photocatalysis“. Chemical Science 11, Nr. 6 (2020): 1494–502. http://dx.doi.org/10.1039/c9sc04882k.
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Covalent organic frameworks (COFs) show great promise as heterogeneous photocatalysts, but they have not yet been explored for asymmetric photocatalysis, which is important for the sustainable production of pharmaceuticals and fine chemicals.
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Cao, Nan, Meilan Xi, Xiaoli Li, Jinfang Zheng, Limei Qian, Yitao Dai, Xizhong Song und Shengliang Hu. „Recent Developments in Heterogeneous Photocatalysts with Near-Infrared Response“. Symmetry 14, Nr. 10 (11.10.2022): 2107. http://dx.doi.org/10.3390/sym14102107.
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Photocatalytic technology has been considered as an efficient protocol to drive chemical reactions in a sustainable and green way. With the assistance of semiconductor-based materials, heterogeneous photocatalysis converts solar energy directly into chemical energy that can be readily stored. It has been employed in several fields including CO2 reduction, H2O splitting, and organic synthesis. Given that near-infrared (NIR) light occupies 47% of sunlight, photocatalytic systems with a NIR response are gaining more and more attention. To enhance the solar-to-chemical conversion efficiency, precise regulation of the symmetric/asymmetric nanostructures and band structures of NIR-response photocatalysts is indispensable. Under the irradiation of NIR light, the symmetric nano-morphologies (e.g., rod-like core-shell shape), asymmetric electronic structures (e.g., defect levels in band gap) and asymmetric heterojunctions (e.g., PN junctions, semiconductor-metal or semiconductor-dye composites) of designed photocatalytic systems play key roles in promoting the light absorption, the separation of electron/hole pairs, the transport of charge carriers to the surface, or the rate of surface photocatalytic reactions. This review will comprehensively analyze the four main synthesis protocols for the fabrication of NIR-response photocatalysts with improved reaction performance. The design methods involve bandgap engineering for the direct utilization of NIR photoenergy, the up-conversion of NIR light into ultraviolet/visible light, and the photothermal effect by converting NIR photons into local heat. Additionally, challenges and perspectives for the further development of heterogeneous photocatalysts with NIR response are also discussed based on their potential applications.
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Liu, Peng, Weijun Dai, Xianfu Shen, Xiang Shen, Yuxiang Zhao und Jian-Jun Liu. „Recent Advances in the Utilization of Chiral Covalent Organic Frameworks for Asymmetric Photocatalysis“. Molecules 29, Nr. 21 (23.10.2024): 5006. http://dx.doi.org/10.3390/molecules29215006.
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The use of light energy to drive asymmetric organic transformations to produce high-value-added organic compounds is attracting increasing interest as a sustainable strategy for solving environmental problems and addressing the energy crisis. Chiral covalent organic frameworks (COFs), as porous crystalline chiral materials, have become an important platform on which to explore new chiral photocatalytic materials due to their precise tunability, chiral structure, and function. This review highlights recent research progress on chiral COFs and their crystalline composites, evaluating their application as catalysts in asymmetric photocatalytic organic transformations in terms of their structure. Finally, the limitations and challenges of chiral COFs in asymmetric photocatalysis are discussed, with future opportunities for research being identified.
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Gao, Zhongwei, Changqing Pan, Chang-Ho Choi und Chih-Hung Chang. „Continuous-Flow Photocatalytic Microfluidic-Reactor for the Treatment of Aqueous Contaminants, Simplicity, and Complexity: A Mini-Review“. Symmetry 13, Nr. 8 (23.07.2021): 1325. http://dx.doi.org/10.3390/sym13081325.
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Water pollution is a growing global issue; there are many approaches to treating wastewater, including chemical coagulation, physical adsorption, and chemical oxidation. The photocatalysis process has provided a solution for removing pollutants from wastewater, where the pair of the photoelectron and hole works through an asymmetric way to degrade the contaminants under UV irradiation. This method offers an alternative route for treating the pollutant with a lower energy cost, high efficiency, and fewer byproducts. A continuous-flow microfluidic reactor has a channel size from tens to thousands of micrometers, providing uniform irradiation and short diffusion length. It can enhance the conversion efficiency of photocatalysis due to the simple spatial symmetry inside the microreactor channel and among the individual channels. In addition, the bandgap of TiO2, ZnO, or other photocatalyst nanoparticles with symmetric crystal structure can be modified through doping or embedding. In this mini-review, a review of the reported continuous-flow photocatalytic microfluidic reactor is discussed from the perspective of both microreactor design and material engineering.
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Chapman, Steven J., Wesley B. Swords, Christine M. Le, Ilia A. Guzei, F. Dean Toste und Tehshik P. Yoon. „Cooperative Stereoinduction in Asymmetric Photocatalysis“. Journal of the American Chemical Society 144, Nr. 9 (22.02.2022): 4206–13. http://dx.doi.org/10.1021/jacs.2c00063.
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Liu, Yang, Jiangtao Li, Xinyi Ye, Xiaowei Zhao und Zhiyong Jiang. „Organocatalytic asymmetric formal arylation of benzofuran-2(3H)-ones with cooperative visible light photocatalysis“. Chemical Communications 52, Nr. 97 (2016): 13955–58. http://dx.doi.org/10.1039/c6cc07105h.
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Hong, Bor-Cherng. „Enantioselective synthesis enabled by visible light photocatalysis“. Organic & Biomolecular Chemistry 18, Nr. 23 (2020): 4298–353. http://dx.doi.org/10.1039/d0ob00759e.
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Wang, Chengfeng, und Zhan Lu. „Catalytic enantioselective organic transformations via visible light photocatalysis“. Organic Chemistry Frontiers 2, Nr. 2 (2015): 179–90. http://dx.doi.org/10.1039/c4qo00306c.
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Jiang, Chunhui, Wei Chen, Wen-Hua Zheng und Hongfei Lu. „Advances in asymmetric visible-light photocatalysis, 2015–2019“. Organic & Biomolecular Chemistry 17, Nr. 38 (2019): 8673–89. http://dx.doi.org/10.1039/c9ob01609k.
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Asymmetric visible-light photocatalysis has recently drawn considerable attention of the scientific community owing to its unique activation modes and significance for the enantioselective green synthesis.
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Long, Chao-Jiu, Yan-Hong He und Zhi Guan. „Asymmetric oxidative Mannich reactions promoted by photocatalysis and electrochemistry“. Organic & Biomolecular Chemistry 20, Nr. 13 (2022): 2544–61. http://dx.doi.org/10.1039/d2ob00054g.
Der volle Inhalt der QuelleDissertationen zum Thema "Asymmetric photocatalysis"
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HERBRIK, FABIAN. „(ASYMMETRIC) PHOTOCATALYSIS UNDER HOMOGENEOUS AND HETEROGENEOUS CONDITIONS - OPTIMIZATION IN CONTINUO, NOVEL CATALYTIC REACTORS AND MATERIALS“. Doctoral thesis, Università degli Studi di Milano, 2022. http://hdl.handle.net/2434/938229.
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Solid supported catalysts exhibit several advantages over the homogenous ones – to name only a few: ease of catalyst separation and low catalyst loadings under continuous operation. This work shows how careful fine-tuning of solid supported material, transmission-based considerations (photocatalyst choice, concentration, and other methodologies) allowed to overcome the difficulties with the inefficient irradiation of reaction mixtures. Generally, the herein described solid supported catalyst shows higher degrees of enantioinduction than its homogeneous counterpart often even higher degrees than previously reported in literature by MacMillan et al and Melchiorre et al. By building a homemade chiral reactor for continuous flow operations productivity was greatly increased when comparing to the batch process, with significantly decreased catalysts loading. Ultimately the applicability of the material was proven by employing it in the telescoped synthesis of an approved antidiabetic drug – Mitiglinide in high yield and satisfactory enantioselectivity.
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Coutant, Corinne. „Développement de nouvelles structures dérivées du BODIPY pour des applications en catalyse et en photothérapie dynamique antibactérienne“. Electronic Thesis or Diss., Nantes Université, 2024. http://www.theses.fr/2024NANU4027.
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L’oxygène singulet (¹O₂), état excité du dioxygène, trouve des applications dans divers domaines tels que la synthèse organique, la science des matériaux ou encore dans le milieu médical. Dans ces travaux de doctorat, deux applications majeures de l’1O2 ont été mises en avant : l’organophotocatalyse asymétrique et la photothérapie dynamique antibactérienne (PTDa). Dans ce but, de nouveaux photosensibilisateurs issus du chromophore BODIPY ont été développés. Ce choix reposait avant tout sur les propriétés photophysiques intéressantes du BODIPY et plus particulièrement sa modularité. Ainsi, le premier chapitre de ce manuscrit est consacré à la synthèse de nouveaux photosensibilisateurs bifonctionnels BODIPYs fonctionnalisés sur l’atome de bore et présentant un motif chiral dérivé de la quinine. Ces structures ont été engagées dans différentes réactions d’organophotocatalyse asymétrique afin d’en tester l’efficacité. Le second chapitre vise le développement de BODIPYs fonctionnalisés sur l’atome de bore afin d’accéder à des structures de type rotaxane. Dans le troisième chapitre, en repartant des résultats précédemment obtenus, de nouveaux rotaxanes dérivés de BODIPYs ont été synthétisés. Leurs propriétés photophysiques et antibactériennes ont également pu être quantifiées dans un second temps. Enfin, dans un quatrième et dernier chapitre, la synthèse de rotaxanes à base de BODIPY présentant des propriétés de fluorescence ou de production en ¹O₂ modulables selon l’acidité du milieu a été mise au pointSinglet oxygen (¹O₂), an excited state of dioxygen, has applications in various fields such as organic synthesis, materials science, and medicine. In this PhD work, two major applications of ¹O₂ are highlighted: asymmetric organophotocatalysis and antibacterial photodynamic therapy (aPDT). New photosensitizers based on the BODIPY chromophore are developed for those purposes. BODIPY is chosen mainly for its interesting photophysical properties, especially its modularity. The first chapter of this manuscript shows the synthesis of new bifunctional BODIPYs photosensitizers with a functionalized boron and featuring a chiral unit derived from quinine. The efficacy of these structures is tested in various asymmetric organophotocatalysis reactions. The second chapter focuses on developing new boron-functionalized BODIPYs to obtain rotaxane-type structures. In the third chapter, building on the previous results, we synthesize new BODIPY-derived rotaxanes and quantify their photophysical and antibacterial properties. Finally, in the fourth and last chapter, we develop new syntheses of BODIPY-based rotaxanes, with fluorescence or ¹O₂ production properties that can be modulated according to the medium's acidity
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Bastida, Borrell David. „Novel Enantioselective Aminocatalytic Processes by means of Vinylogous Reactivity and Photoredox Catalysis“. Doctoral thesis, Universitat Rovira i Virgili, 2015. http://hdl.handle.net/10803/668081.
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En aquesta tesi es mostra com la aminocatàlisis pot ser utilitzada per resoldre diferents problemes en síntesis orgànica. La combinació de la aminocatàlisis amb el concepte de la vinilogia per tal de funcionalitzar enantioselectivament posicions llunyanes dels grups carbonílics ha sigut l’eix central en el primer projecte. S’ha utilitzat una amina bifuncional amb una tiourea capaç de catalitzar una reacció aldòlica en posició γ mitjançant la formació de la dienamina combinada amb la direcció de l'aproximació del acceptor (electròfil) mitjançant enllaços d'hidrogen amb el dador (tiourea). En el segon projecte s’ha utilitzat una amina secundaria quiral per desenvolupar una reacció en cascada de tres components. S'ha aconseguint funcionalitzar regioselectivament posicions δ de dienals. Els compostos Espiro-Oxindolic Ciclohexans han estat obtinguts amb una completa puresa òptica. Per últim s’ha desenvolupat mitjançant la combinació de la aminocatàlisis i la fotocatàlisis una addició conjugada enantioselectiva de radicals alquílics generats mitjançant la fotocatàlisi a ions imini quirals generats in-situ a partir de cetones insaturades i amines primàries.En esta tesis se muestra como la aminocatálsis puede ser utilizada para solventar diversos problemas en síntesis orgánica. La combinación de la aminocatálisis con el concepto de la vinilogia para funcionalizar enantioselectivamente posiciones lejanas de compuestos carbonílicos, ha sido el eje del primer proyecto. En dicho proyecto se ha utilizado una amina bifuncional con un grupo tiourea para el desarrollo de una reacción aldólica en posición γ, mediante la formación de la dienamina combinada con la dirección del aceptor (electrofilo) mediante enlaces de hidrogeno con el dador (tiourea). En el segundo proyecto, se ha utilizado una amina secundaria quiral para desarrollar una reacción en cascada de tres componentes consiguiendo funcionalizar regioselectivamente posiciones δ de dienales. Los compuestos espiro-oxindolic ciclohexanos fueron obtenidos con total pureza óptica. En ultimo caso se ha desarrollado mediante la combinación de la aminocatalisis y la fotocatalisis, una addición conugada enantioselectiva de radicales alquílicos generados mediante fotocatalisis a iones iminio quirales, generados in situ a partir de cetonas insaturadas y aminas primarias.
In the present thesis it is shown how aminocatalysis may be used to solve some problems for synthetic organic chemists'. Combination of aminocatalysis with the concept of vinylogy is the key concept for the enantioselective functionalization of remote positions of carbonyl compounds. In the first project a bifunctional primary amine-thiourea catalyst that can combine H-bond-directing activation of the electrophile with the dienamine activation for an asymmetric vinylogous aldol reaction. In the second project, using a chiral secondary amine we expanded the potential of organocascade catalysis by including vinylogous reactivity functionalizing exclusive δ poitions. In the last project, we developed an enantioselective radical conjugate addition of enones by trapping photochemically generated carbon-centered radicals using iminium ion activation generated in-situ by condensation of primary amines with enones.
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Kong, Julie. „Design, synthesis and applications of new chiral bifunctional iminophosphorane - thiourea organocatalysts. Organophotocatalytic addition of unactivated alkenes with silicon enolate“. Electronic Thesis or Diss., université Paris-Saclay, 2024. http://www.theses.fr/2024UPASF018.
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Ce travail de thèse porte sur le développement de nouveaux organocatalyseurs chiraux bifonctionnels et leurs applications en organocatalyse asymétrique. Pour ce faire, nous avons d'abord étudié la conception et la synthèse de nouveaux organocatalyseurs chiraux possédant une fonction iminophosphorane, d'une part et une fonction donneuse de liaison hydrogène, d'autre part. Ainsi, plusieurs familles d'organocatalyseurs chiraux bifonctionnels à base de L-proline et d'acide (S)-pyroglutamique ont été synthétisées en quelques étapes avec des rendements globaux modérés à bons. Ces nouveaux catalyseurs ont été évalués par la suite dans diverses réactions asymétriques. Le grand potentiel de ces catalyseurs a été démontré dans la synthèse d'α-acyloxythioester par transfert d'acyle suivi d'une protonation énantiosélective via l'intermédiaire énolate d'α-acyloxy-β-cétosulfure. De très bons rendements (jusqu'à 94 %) et énantiosélectivités (jusqu'à 98 %) ont été obtenus. Le catalyseur le plus performant a été ensuite immobilisé sur support résine et évalué dans la même réaction. D'une manière générale, les réactions se sont bien déroulées conduisant à la formation des produits attendus avec de bons rendements et énantiosélectivités. Au cours de ce travail, l'exploration d'une nouvelle méthodologie pour la fonctionnalisation d'alcènes non-activés par voie organophotocatalytique a été étudiée. Les oléfines représentent une grande classe de composés chimiques. De nombreuses méthodes ont été développées pour la fonctionnalisation d'alcènes activés. Cependant, la fonctionnalisation des alcènes non-activés reste un challenge synthétique. Par conséquent, développer de nouveaux outils synthétiques pour résoudre ce problème reste un défi pour les chimistes organiciensThe PhD work focuses on the development of new bifunctional chiral organocatalysts and their applications in asymmetric organocatalysis. For this purpose, we first studied the design and synthesis of new chiral organocatalysts possessing an iminophosphorane function, on the one hand, and a hydrogen bond donor function, on the other hand. Thus, several families of bifunctional chiral organocatalysts based on L-proline and (S)-pyroglutamic acid have been synthesized in a few steps with moderate to good overall yields. These new catalysts were subsequently evaluated in various asymmetric reactions. The great potential of these catalysts has been demonstrated in the synthesis of α-acyloxythioester through enantioselective acyl transfer /protonation of α-acyloxy-β-ketosulfides. Very good yields (up to 94%) and enantioselectivities (up to 98%) were obtained. The best performing catalyst was then immobilized on a resin support and evaluated in the same reaction. Generally speaking, the reactions worked well leading to the formation of the expected products in good yields and enantioselectivity. During this work, the exploration of a new methodology for the functionalization of non-activated alkenes by organophotocatalytic route was studied. Olefins represent a large class of chemical compounds. Several methods have been developed for the functionalization of activated alkenes. However, the functionalization of non-activated alkenes remains a synthetic challenge. Therefore, developing new synthetic tools to solve this problem remains a challenge for organic chemists
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Bouchet, Damien. „Applications de l'organocatalyse asymétrique et de la photocatalyse aux additions nucléophiles sur des dérivés α,β-insaturés électroappauvris“. Electronic Thesis or Diss., université Paris-Saclay, 2024. http://www.theses.fr/2024UPASF001.
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Les additions nucléophiles sur les accepteurs de Michael comptent parmi les réactions les plus fondamentales de la chimie organique. Elles n'ont eu de cesse d'être revisitées, notamment au gré de l'emploi de dérivés α,β-insaturés peu conventionnels. La catalyse permet de démultiplier leurs potentialités tout en s'inscrivant dans une démarche plus respectueuse de l'environnement. Aussi, cette thèse s'ouvre par une partie dédiée à l'organocatalyse asymétrique. Le premier chapitre relate le développement d'une cycloaddition (4 + 2) asymétrique promue par des isothiourées et permettant la synthèse d'anti-2,3-dihydrothiopyranones. La réactivité singulière des thiochalcones, utilisées pour la première fois en tant qu'accepteurs de Michael, y est mise en exergue. Un deuxième chapitre est consacré à une cycloaddition (3 + 2) entre des quinones diimines et des énecarbamates médiée par les acides phosphoriques chiraux. Elle a conduit à des indolines 2,3-disubstituées. Étonnamment, des produits acycliques de ζ-amination ont été formés en étendant cette transformation aux triénecarbamates. Ils résultent d'une addition 1,6 sur l'azote des quinones diimines. Afin d'optimiser la stéréosélectivité de cette transformation, nous nous sommes tournés vers l'intelligence artificielle. Une seconde partie porte sur une désaromatisation photocatalytique d'indoles électoappauvris en C3 par C2-acylation. Elle repose sur l'addition de radicaux générés à partir d'aldéhydes par un HAT direct opéré par le TBADT, un polyoxométallateNucleophilic additions to Michael acceptors constitute one of the most fundamental class of reactions in organic chemistry. They have been frequently revisited using unconventional α,β-unsaturated derivatives. Catalysis drastically increases their potential while falling within an environmentally-friendly approach. Hence, this manuscript begins with a first part devoted to asymmetric organocatalysis. The opening chapter focuses on the development of an asymmetric (4 + 2)-cycloaddition promoted by isothioureas. It enabled the synthesis of anti-2,3-dihydrothiopyranones while showcasing the peculiar reactivity of thiochalcones. They were used, for the first time, as Micheal acceptors. The second chapter is dedicated to a (3 + 2)-cycloaddition between quinones diimines and enecarbamates. It led to 2,3-disubstituted indolines. Surprisingly, ζ-amination acyclic products were obtained when we extended this transformation to trienecarbamates. They resulted from a 1,6-addition on the nitrogen of quinone diimines. Aiming to optimize the stereoselectivity of this transformation, we turned our attention towards artificial intelligence. A second part deals with a photocatalytic dearomatization of indoles bearing an electron-withdrawing group at C3 position via their C2-acylation. It relied on the addition of acyl radical species generated from aldehydes through a HAT mediated by a polyoxometalate: the TBADT
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Traboulsi, Iman. „Radical Additions onto Functionalized Chiral Cyclobutenes. Application to the Total Syntheses of Eucophylline and Eburnamine. A Biomimetic Approach Towards Leucophyllidine“. Thesis, Bordeaux, 2020. http://www.theses.fr/2020BORD0282.
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Cette thèse décrit une nouvelle approche à la sulfonyl-cyanation de cyclobutènes chiraux à l’aide d’un simple photocatalyseur, le p-anisaldéhyde. Cette réaction a permis d’introduire un centre quaternaire tout-carboné d’une manière régio-, stéréo- et diastéréocontrôlée, via un processus par transfert d’énergie. Différentes stratégies d’élimination du groupement sulfonylé et d’ouverture de cycle des cyclobutanes correspondants ont ensuite été examinées afin de donner accès à une nouvelle bibliothèque de dérivés fonctionnalisés. Un processus basé sur l’utilisation de borure de nickel a permis de mettre au point une séquence en cascade en “ un-pot ” de réduction de la fonction nitrile / cyclisation / ouverture de cycle donnant accès à un lactame cyclique à six chaînons à partir des cyclobutanes ci-dessus. Cette chimie a été appliquée à la synthèse totale énantiosélective de l’eucophylline, le fragment sud de la leucophyllidine, un alcaloïde terpène bis-indole cytotoxique isolé de Leuconotis griffithii et L. eugenifolius. La synthèse racémique de l’éburnamine, le fragment nord, a également été réalisée en 10 étapes à partir d’un substrat commercialement disponible. Le couplage biomimétique de ces deux fragments a ensuite été examiné en utilisant un modèle de l’eucophyllineThis Ph.D. thesis describes a new approach to the sulfonyl-cyanation of chiral cyclobutenes using p-anisaldehyde as a simple photocatalyst. This reaction allowed the introduction of an all-carbon quaternary stereocenter in a regio-, stereo- and diastereocontrolled manner, via an energy transfer process. Different strategies for the removal of the sulfonyl group and ring-opening of the corresponding cyclobutanes were then examined to provide access to a new library of functionalized derivatives. A process based on the use of nickel boride allowed the development of a “one-potˮ cascade sequence of nitrile function reduction/cyclization/ring-opening giving access to a six-membered cyclic lactam from above cyclobutanes. This chemistry has been applied to the enantioselective total synthesis of eucophylline, the southern fragment of leucophyllidine, a cytotoxic bis-indole terpene alkaloid isolated from Leuconotis griffithii and L. eugenifolius. The racemic synthesis of eburnamine, the northern fragment, was also performed in 10 steps from a commercially available substrate. The biomimetic coupling of these two fragments was then examined using an eucophylline model
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Marchal, Lucas. „Synthèse de nouveaux candidats médicamenteux présentant une chiralité axiale C-N par le développement de nouveaux couplages C-N atroposélectifs“. Electronic Thesis or Diss., Strasbourg, 2024. http://www.theses.fr/2024STRAF029.
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Les composés à chiralité axiale C–N ont démontré un potentiel significatif dans divers domaines, en particulier dans l'industrie pharmaceutique. Cependant, il existe actuellement peu de méthodologies connues permettant d’accéder à ces composés, et elles sont généralement limitées à des structures moléculaires très spécifiques. Afin de préparer de nouveaux atropisomères C–N d'intérêt, des méthodologies synthétiques innovantes doivent être développées. À cette fin, nous avons concentré nos efforts sur l'utilisation de sels de diaryliodonium comme partenaires de couplage hautement réactifs, ce qui nous a permis de concevoir un nouveau couplage C–N atropo-énantiosélectif catalysé au cuivre pour obtenir des benzoxazolones N-arylées énantio-enrichies. Les applications potentielles bioactives de ces molécules ont été étudiées et des études mécanistiques ont été menées pour concevoir un cycle catalytique pour ce couplage. De telles investigations approfondies ont été possibles grâce à une collaboration interdisciplinaire fructueuse. Le développement de nouvelles méthodologies a été étendu au premier couplage C–N atropo-énantiosélectif photoinduitC–N axially chiral compounds have demonstrated significant potential across various fields, especially in the pharmaceutical industry. However, there are currently only few known methodologies to access these compounds, which are generally restricted to very specific molecular scaffolds. In order to prepare new C–N atropisomers of interest, innovative synthetic methodologies must be develop. To this purpose, we focused our efforts of the use of diaryliodonium salts as highly reactive coupling partners which allowed us to design a new copper-catalyzed atropo-enantioselective C–N coupling to afford enantio-enriched N-aryl benzoxazolones. The potential bioactive applications of such molecules has been studied and mechanistic studies were carried out to design a catalytic cycle for coupling. Such in-depth investigations were possible thanks to a fruitful interdisciplinary collaboration. The development of new methodologies was further extended through the first photoinduced atropo-enantioselective C–N coupling
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Levitre, Guillaume. „Photocatalyse et organocatalyse comme outils innovants pour la synthèse de molécules complexes“. Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLS380.
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Face aux enjeux environnementaux actuels, la catalyse est devenue un outil majeur pour la synthèse de molécules complexes et à visées thérapeutiques. Dans ce contexte, nous nous sommes intéressés au développement de nouvelles méthodes de synthèses innovantes, efficaces, sans métaux ou activées par la lumière visible. Ainsi, mes travaux de thèse ont fait appel à deux thématiques largement étudiées au sein de notre laboratoire que sont la catalyse photorédox et l'organocatalyse. Dans ce manuscrit, la première partie porta sur la conception de réactions multicomposants photocatalysées pour la synthèse de structures trifluorométhylées avec de bons rendements. La partie suivante a été consacrée au développement et à l’évaluation de nouveaux photocatalyseurs supportés, robustes et recyclables. La troisième partie présenta l’élaboration de réactions de cyloadditions formelles (4+3) et (4+2), catalysées aux acides phosphoriques chiraux pour une synthèse efficace, énantiosélective et diastéréosélective de cyclohepta[b]indoles et de spiroindolines. Dans la quatrième partie, une stratégie combinant l’organocatalyse asymétrique et la photocatalyse pour la synthèse de tryptamines α-substituées β-aminées potentiellement biologiquement actives a été décrite. Enfin, l’élaboration de nouveaux composés d’iode hypervalent chiraux et leur évaluation en tant qu’organocatalyseurs fût rapportées dans la dernière partie de ce manuscrit de thèseIn front of current environmental challenges, catalysis has become a major tool for the synthesis of complex and therapeutic molecules. In this context, we have focused on the development of new synthesis methods that are innovative, efficient, metal-free or activated by visible light. Thus, my thesis work has involved two themes that have been widely studied in our team: photoredox catalysis and organocatalysis. In this manuscript, the first part focused on the conception of photocatalyzed multicomponent reactions for the synthesis of trifluoromethylated structures with good yields. The following section devoted to the design and evaluation of new supported, robust and recyclable photocatalysts. The third part presented the formulation of formal (4+3) and (4+2) cyloaddition reactions, catalyzed with chiral phosphoric acids for an effective, enantio- and diastereo-selective synthesis of cyclohepta[b]indoles and spiroindolines. In the fourth part, a strategy combining asymmetric organocatalysis and photocatalysis for the synthesis of potentially biologically active α-substituted β-amino tryptamines was described. Finally, the elaboration of new chiral hypervalent iodine compounds and their evaluation as organocatalysts was reported in the last part of this thesis manuscript
Buchteile zum Thema "Asymmetric photocatalysis"
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Afewerki, Yi‑Yin, Jing Liu, Liang‑Qiu Liu und Wen‑Jing Xiao. „Organocatalysis Combined with Photocatalysis“. In Asymmetric Organocatalysis Combined with Metal Catalysis, 67–81. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-43851-7_3.
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Marzo, Leyre, und José Alemán. „Recent approaches in asymmetric non-covalent organo-photocatalysis“. In Photochemistry, 283–302. Cambridge: Royal Society of Chemistry, 2022. http://dx.doi.org/10.1039/9781839167676-00283.
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Jia, Yue, Xiang-Kui He, Liang-Qiu Lu und Wen-Jing Xiao. „Asymmetric Oxidation Using Photocatalysis“. In Reference Module in Chemistry, Molecular Sciences and Chemical Engineering. Elsevier, 2024. http://dx.doi.org/10.1016/b978-0-323-96025-0.00113-7.
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Zhu, Yue-Die, und Pu-Sheng Wang. „Photocatalytic enantioselective radical transformation enabled by radical–polar crossover“. In Photochemistry, 455–66. Royal Society of Chemistry, 2023. http://dx.doi.org/10.1039/bk9781837672301-00455.
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Asymmetric transformation of radicals has always been recognized as a highly challenging issue, compared with the well-developed enantioinduction methods in traditional polar/ionic chemistry. Enantioselective radical polar crossover (RPC) reactions have recently emerged as valuable and powerful tools to assemble molecular complexity that would be impossible using either a radical or polar approach alone. This chapter summarizes the recent and synthetically important stereoselective RPC transformations by merging photoredox catalysis.
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Mandal, R., B. Garai und B. Sundararaju. „2.5 Cobalt-Catalyzed Bidentate-Chelation-Assisted C—H Functionalization“. In Base-Metal Catalysis 2. Stuttgart: Georg Thieme Verlag KG, 2023. http://dx.doi.org/10.1055/sos-sd-239-00273.
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AbstractC—H bond functionalization catalyzed by high-valent-cobalt species with the aid of bidentate chelation has come a long way since the pioneering report by Daugulis almost a decade ago. Further study of the reaction mechanisms revealed that stoichiometric amounts of metal salts could be replaced with photocatalysts or electricity as one-electron oxidants, and approaches based on these strategies can be considered more environmentally friendly than the initially developed catalytic systems. Systematic investigations have led to a better understanding of the coordination environment of the in-situ-formed cobaltacycle, and this has led to the development of external chiral ligands for cobalt-catalyzed asymmetric C—H functionalizations. This review is a comprehensive summary of the documented methods for cobalt-catalyzed, bidentate-chelation-assisted C—H bond functionalizations as of early 2023.
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Lin, Yu-Mei, und Lei Gong. „Asymmetric Photochemical Transformations Using a Chiral Lewis Acid or/and Chiral Photocatalyst“. In Reference Module in Chemistry, Molecular Sciences and Chemical Engineering. Elsevier, 2024. http://dx.doi.org/10.1016/b978-0-32-390644-9.00136-0.
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Griffith, Allison K., und Tristan H. Lambert. „Alkenes“. In Organic Synthesis. Oxford University Press, 2017. http://dx.doi.org/10.1093/oso/9780190646165.003.0027.
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The α-C–H functionalization of piperidine catalyzed by tantalum complex 1 to produce amine 2 was developed (Org. Lett. 2013, 15, 2182) by Laurel L. Schafer at the University of British Columbia. An asymmetric diamination of diene 3 with diaziridine reagent 4 under palladium catalysis to furnish cyclic sulfamide 5 was developed (Org. Lett. 2013, 15, 796) by Yian Shi at Colorado State University. Enantioenriched β-fluoropiperdine 8 was prepared (Angew. Chem. Int. Ed. 2013, 52, 2469) via aminofluorocyclization of 6 with hypervalent iodide 7, as reported by Cristina Nevado at the University of Zurich. Erick M. Carreira at ETH Zürich disclosed (J. Am. Chem. Soc. 2013, 135, 6814) a ruthenium-catalyzed hydrocarbamoylation of allylic formamide 9 to yield pyrrolidone 10. Hans-Günther Schmalz at the University of Köln disclosed (Angew. Chem. Int. Ed. 2013, 52, 1576) an asymmetric hydrocyanation of styrene 11 with Ni(cod)₂ and phosphine–phosphite ligand 12 to yield exclusively the branched cyanide 13. A similar transformation of styrene 11 to the hydroxycarbonylated product 15 was catalyzed (Chem. Commun. 2013, 49, 3306) by palladium complex 14, as reported by Matthew L. Clarke at the University of St Andrews. Feng-Ling Qing at the Chinese Academy of Sciences found (Angew. Chem. Int. Ed. 2013, 52, 2198) that the hydrotrifluoromethylation of unactivated alkene 16 to 17 was catalyzed by silver nitrate. The same transformation was also reported (J. Am.Chem. Soc. 2013, 135, 2505) by Véronique Gouverneur at the University of Oxford using a ruthenium photocatalyst and the Umemoto reagent 18. Clark R. Landis at the University of Wisconsin, Madison reported (Angew. Chem. Int. Ed. 2013, 52, 1564) a one-pot asymmetric hydroformylation using 21 followed by Wittig olefination to transform alkene 19 into the γ-chiral α,β-unsaturated carbonyl compound 20. Debabrata Mati at the Indian Institute of Technology Bombay found (J. Am. Chem. Soc. 2013, 135, 3355) that alkene 22 could be nitrated stereoselectively with silver nitrite and TEMPO to form alkene 23. Damian W. Young at the Broad Institute disclosed (Org. Lett. 2013, 15, 1218) that a macrocyclic vinylsiloxane 24, which was synthesized via an E-selective ring closing metathesis reaction, could be functionalized to make either E- or Z-alkenes, 25 and 26.
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Faisca Phillips, A. M., M. F. C. Guedes da Silva und A. J. L. Pombeiro. „19 Enantioselective Cross-Dehydrogenative Coupling“. In Cross-Dehydrogenative Coupling. Stuttgart: Georg Thieme Verlag KG, 2023. http://dx.doi.org/10.1055/sos-sd-240-00196.
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AbstractThe possibility of creating a chiral center directly from two C—H bonds, or from a C—H bond and an X—H bond (X = heteroatom), without any prior derivatization (e.g., the installation of a leaving group) opens up many new possibilities in synthesis. Many chiral ligands and organocatalysts have now been discovered to be compatible with the oxidizing conditions in which these transformations take place. Furthermore, as reactions that can be performed under milder conditions are found, such as those that involve the use of molecular oxygen or even air to accept the two hydrogen atoms lost, or that can be run at lower temperatures, the repertoire of cross-dehydrogenative coupling (CDC) methodologies has become even bigger. Ligands such as mono- and bisoxazolines, bisphosphines, axially chiral binaphthols and bi-2-naphthylamine derivatives, and salens, as well as organocatalysts such as amino acids, chiral amines and diamines, cinchona alkaloids, axially chiral phosphoric acids, imidodiphosphoric acids, imidazolinones, and thioureas, amongst others, have been found to be robust and to perform well under CDC reaction conditions, providing high asymmetric induction and good yields of products. Some of these catalysts also work well in synergy with another catalyst. Recent developments in this area include the use of light energy for activation in combination with photocatalysts, as well as methods based on the use of electrochemistry. In this review, methods involving CDC that have been developed for the synthesis of molecules with one or more chiral centers, including compounds with axial or planar chirality, are presented, and their scope and limitations are discussed. The organization is based firstly on the type of catalysis used, and then divided further according to the type of bond being formed.
Berichte der Organisationen zum Thema "Asymmetric photocatalysis"
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Echeverrigaray, Fernando, und Fernando Alvarez. Nanocrystalline heterophase boundaries and asymmetric topographies for enhanced photocatalysts produced by dual ion beam-assisted deposition. Peeref, April 2023. http://dx.doi.org/10.54985/peeref.2304p5860036.
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