Relevant bibliographies by topics / Enantioselective

Academic literature on the topic 'Enantioselective'

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Published: 4 June 2021
Last updated: 7 July 2024

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Journal articles on the topic "Enantioselective"

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Gualandi, Andrea, Luca Mengozzi, and Pier Cozzi. "Stereoselective SN1-Type Reaction of Enols and Enolates." Synthesis 49, no. 15 (June 13, 2017): 3433–43. http://dx.doi.org/10.1055/s-0036-1588871.

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Stereoselective alkylation of enolates represents a valuable and important procedure for accessing carbon–carbon-bond frameworks in natural and nonnatural product synthesis. Usually, activated electrophilic partners that react through an SN2 mechanism are employed. To overcome the limitations due to reduced reactivity and steric hindrance, SN1-type reactions can be considered a valid and practical alternative. Accessible enolates can be used in stereoselective (diastereo- or enantioselective) reactions with electrophilic carbenium ions, either used as stable reagents or generated in situ from suitable precursors. The results achieved in this active field are summarized in this review.1 Introduction2 Alcohols in SN1-Type Reactions with Enolates2.1 Enantioselective Reactions with Metal Complexes2.2 Organocatalytic Enantioselective Reactions3 Alcohols and Alcohol Derivatives in SN1-Type Reactions with Enolates­: Enantioselective Reactions with Metal Enolates4 Isolated Carbenium Ions in SN1-Type Reactions with Enolates: Enantioselective­ Reactions with Metal Enolates5 Miscellaneous6 Conclusion
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Zhang, Yafeng, Huizhen Wang, Hu Yu, and Xiaoxia Sun. "Chiral fluorescent sensor based on H8-BINOL for the high enantioselective recognition of d- and l-phenylalanine." RSC Advances 12, no. 19 (2022): 11967–73. http://dx.doi.org/10.1039/d2ra00803c.

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A triazole-modified H8-BINOL fluorescence sensor was synthesized with 95% yield, which can enantioselectively recognize l-phenylalanine without the participation of metal ions, even the enantioselective fluorescence enhancement ratio was up to 104.28.
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Jakob, Bastian, Nico Schneider, Luca Gengenbach, and Georg Manolikakes. "Palladium-catalyzed enantioselective three-component synthesis of α-arylglycine derivatives from glyoxylic acid, sulfonamides and aryltrifluoroborates." Beilstein Journal of Organic Chemistry 19 (May 25, 2023): 719–26. http://dx.doi.org/10.3762/bjoc.19.52.

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A palladium-catalyzed enantioselective three-component reaction of glyoxylic acid, sulfonamides and aryltrifluoroborates is described. This process provides modular access to the important α-arylglycine motif in moderate to good yields and enantioselectivies. The formed α-arylglycine products constitute useful building blocks for the synthesis of peptides or arylglycine-containing natural products.
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He, Chuan, and Wei Yuan. "Enantioselective C–H Functionalization toward Silicon-Stereogenic Silanes." Synthesis 54, no. 08 (January 3, 2022): 1939–50. http://dx.doi.org/10.1055/a-1729-9664.

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AbstractIn recent years, transition-metal-catalyzed enantioselective C–H bond functionalization has emerged as a powerful and attractive synthetic approach to access silicon-stereogenic centers, which provides impetus for the innovation of chiral organosilicon chemistry. This short review summarizes recent advances in the construction of silicon-stereogenic silanes via transition-metal-catalyzed enantioselective C–H functionalization. We endeavor to highlight the great potential of this methodology and hope that this review will shed light on new perspectives and inspire further research in this emerging area.1 Introduction2 Enantioselective C–H Functionalization Induced by Oxidative Addition­ of an Aryl-OTf Bond3 Enantioselective C–H Functionalization Induced by Oxidative Addition­ of a Silacyclobutane4 Directing-Group-Assisted Enantioselective C–H Functionalization5 Enantioselective Dehydrogenative C–H/Si–H Coupling5.1 Enantioselective C(sp2)–H Silylation5.2 Enantioselective C(sp3)–H Silylation6 Summary and Outlook
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Gong, Liu-Zhu, Pu-Sheng Wang, and Meng-Lan Shen. "Transition-Metal-Catalyzed Asymmetric Allylation of Carbonyl Compounds with Unsaturated Hydrocarbons." Synthesis 50, no. 05 (December 21, 2017): 956–67. http://dx.doi.org/10.1055/s-0036-1590986.

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The asymmetric allylation of carbonyl compounds is an important process for the formation of carbon–carbon bonds, generating optically active homoallylic alcohols that are versatile building blocks with widespread applications in organic synthesis. The use of readily available unsaturated hydrocarbons as allylating reagents in the transition-metal-catalyzed asymmetric allylation has received increasing interest as either a step- or an atom-economy alternative. This review summarizes transition-metal-catalyzed enantioselective allylations on the basis of the ‘indirect’ and ‘direct’ use of simple unsaturated hydrocarbons (include dienes, allenes, alkynes, and alkenes) as allylating reagents, with emphasis on highlighting conceptually novel reactions.1 Introduction2 ‘Indirect’ Use of Unsaturated Hydrocarbons in Asymmetric Allylation of Carbonyl Compounds2.1 Enantioselective Allylation with 1,3-Dienes2.2 Enantioselective Allylation with Allenes2.3 Enantioselective Allylation with Alkenes3 ‘Direct’ Use of Unsaturated Hydrocarbons in Asymmetric Allylation of Carbonyl Compounds3.1 Enantioselective Allylation with 1,3-Dienes3.2 Enantioselective Allylation with Allenes3.3 Enantioselective Allylation with Alkynes3.4 Enantioselective Allylation with Alkenes4 Conclusions
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Bower, John F., Timothy P. Aldhous, Raymond W. M. Chung, and Andrew G. Dalling. "Enantioselective Intermolecular Murai-Type Alkene Hydroarylation Reactions." Synthesis 53, no. 17 (May 25, 2021): 2961–75. http://dx.doi.org/10.1055/s-0040-1720406.

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AbstractStrategies that enable the efficient assembly of complex building blocks from feedstock chemicals are of paramount importance to synthetic chemistry. Building upon the pioneering work of Murai and co-workers in 1993, C–H-activation-based enantioselective hydroarylations of alkenes offer a particularly promising framework for the step- and atom-economical installation of benzylic stereocenters. This short review presents recent intermolecular enantioselective Murai-type alkene hydroarylation methodologies and the mechanisms by which they proceed.1 Introduction2 Enantioselective Hydroarylation Reactions of Strained Bicyclic Alkenes3 Enantioselective Hydroarylation Reactions of Electron-Rich Acyclic Alkenes4 Enantioselective Hydroarylation Reactions of Electron-Poor Acyclic Alkenes5 Enantioselective Hydroarylation Reactions of Minimally Polarized Acyclic Alkenes6 Conclusion and Outlook
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Cozzi, Pier Giorgio, Alessandro Mignogna, and Luca Zoli. "Catalytic enantioselective Reformatsky reactions." Pure and Applied Chemistry 80, no. 5 (January 1, 2008): 891–901. http://dx.doi.org/10.1351/pac200880050891.

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The Reformatsky reaction is a venerable named reaction that was introduced more than 120 years ago. Diastereoselective variants based on the use of chiral auxiliary and enantioselective protocols, based on the employment of stoichiometric amount of chiral ligands, have been successfully applied in organic synthesis during the years. However, a facile and general catalytic enantioselective variant was still a difficult task. Recently, we have established a new general and straightforward methodology for catalytic enantioselective Reformatsky reaction based on different concepts. In this paper, we present our general finding in catalytic enantioselective Reformatsky reaction of ketones, imines, and aldehydes. Our simple methodologies could become benchmark reactions for testing new synthesized chiral ligands for asymmetric transformations.
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Brüllingen, Eric, Jörg-Martin Neudörfl, and Bernd Goldfuss. "Enantioselective Cu-catalyzed 1,4-additions of organozinc and Grignard reagents to enones: exceptional performance of the hydrido-phosphite-ligand BIFOP-H." New Journal of Chemistry 43, no. 12 (2019): 4787–99. http://dx.doi.org/10.1039/c8nj05886e.

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Boussonnière, Anne, Anne-Sophie Castanet, and Hélène Guyon. "Transition-Metal-Free Enantioselective Reactions of Organo­magnesium Reagents Mediated by Chiral Ligands." Synthesis 50, no. 18 (June 20, 2018): 3589–602. http://dx.doi.org/10.1055/s-0037-1610135.

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Organomagnesium reagents are among the most important reagents in organic chemistry because of their great utility in forming carbon–carbon bonds. Although most enantioselective reactions using these organometallics involve transmetalation, the past decade has witnessed impressive advances in direct chiral-ligand-mediated reactions of organomagnesiums­. This short review presents an overview of these achievements in enantioselective nucleophilic additions and substitutions.1 Introduction2 Enantioselective Nucleophilic Additions2.1 Addition to C=O Bonds2.2 Addition to C=N Bonds2.3 Addition to C=C Bonds3 Enantioselective Substitution Reactions3.1 Sulfoxide–Magnesium Exchange3.2 Desymmetrization via Anhydride Opening3.3 Asymmetric Allylic Alkylation (AAA)4 Conclusion
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Shukla, Nisha, Zachary Blonder, and Andrew J. Gellman. "Chiral Separation of rac-Propylene Oxide on Penicillamine Coated Gold NPs." Nanomaterials 10, no. 9 (August 30, 2020): 1716. http://dx.doi.org/10.3390/nano10091716.

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The surfaces of chemically synthesized spherical gold NPs (Au-NPs) have been modified using chiral L- or D-penicillamine (Pen) in order to impart enantioselective adsorption properties. These chiral Au-NPs have been used to demonstrate enantioselective adsorption of racemic propylene oxide (PO) from aqueous solution. In the past we have studied enantioselective adsorption of racemic PO on L- or D-cysteine (Cys)-coated Au-NPs. This prior work suggested that adsorption of PO on Cys-coated Au-NPs equilibrates within an hour. In this work, we have studied the effect of time on the enantioselective adsorption of racemic PO from solution onto chiral Pen/Au-NPs. Enantioselective adsorption of PO on chiral Pen/Au-NPs is time-dependent but reaches a steady state after ~18 h at room temperature. More importantly, L- or D-Pen/Au-NPs are shown to adsorb R- or S-PO enantiospecifically and to separate the two PO enantiomers from racemic mixtures of RS-PO.
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Dissertations / Theses on the topic "Enantioselective"

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Wozniak, Lukasz. "New Strategies for Enantioselective Catalysis of Photochemical Reactions." Doctoral thesis, Universitat Rovira i Virgili, 2017. http://hdl.handle.net/10803/458370.

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La tesi descriu noves estratègies per implementar reaccions fotoquímiques enantioselectives promogudes per llum visible. La primera part se centra en el desenvolupament de transformacions químiques que depenen de la formació de complexos donadors-acceptors d'electrons (EDA). Específicament, es desenvolupa la perfluoroalquilació fotoquímica enantioselectiva de β-cetoésters intervinguda per enolats quirals. Aquest estudi estableix la capacitat dels enolats quirals, generats mitjançant transferència de fase (PTC), per actuar com a donadors en la formació de complexos fotoactius EDA amb iodurs de perfluoroalquil, alhora que per proporcionar inducció asimètrica en la generació de centres quaternaris estereogènics de perfluoroalquil. La segona part de la tesi detalla una nova estratègia per dissenyar processos organocatalítics asimètrics en cascada. El nou enfoc combina la diferent reactivitat de dos intermedis organocatalítics quirals; la reactivitat de l'estat excitat d'ions imini quirals amb la reactivitat de l'estat fonamental de les enamines. Aquestes reaccions organofotoquímiques en cascada ens condueixen a la formació de ciclopentanols estereoquímicament densos, compostos als quals no es pot accedir per altres mètodes, amb elevats rendiments i excel·lents selectivitats. Les excel·lents selectivitats observades s'originen mitjançant un mecanisme d'amplificació asimètrica, que es deu a un procés de resolució cinètica operatiu en la segona etapa del procés en cascada
La tesis describe novedosas estrategias para implementar reacciones fotoquímicas enantioselectivas promovidas por luz visible. La primera parte se centra en el desarrollo de transformaciones químicas que dependen de la formación de complejos dadores-aceptores de electrones (EDA). Específicamente, se desarrolla la perfluoroalquilación fotoquímica enantioselectiva de β-cetoésteres mediada por enolatos quirales. Este estudio establece la capacidad de los enolatos quirales, generados mediante transferencia de fase (PTC), para actuar como dadores en la formación de complejos fotoactivos EDA con yoduros de perfluoroalquilo, a la vez que para proporcionar inducción asimétrica en la generación de centros cuaternarios estereogénicos de perfluoroalquilo. La segunda parte de la tesis detalla una nueva estrategia para diseñar procesos organocatalíticos asimétricos en cascada. El nuevo enfoque combina la distinta reactividad de dos intermedios organocatalíticos quirales; la reactividad del estado excitado de iones iminio quirales con la reactividad del estado fundamental de las enaminas. Estas reacciones organofotoquímicas en cascada nos conducen a la formación de ciclopentanoles estereoquímicamente densos, compuestos a los que no se puede acceder por otros métodos, con elevados rendimientos y excelentes selectividades. Las excelentes selectividades observadas se originan mediante un mecanismo de amplificación asimétrica, que se debe a un proceso de resolución cinética operativo en la segunda etapa del proceso en cascada
The thesis describes novel strategies to implement enantioselective photochemical reactions promoted by visible light. The first part focuses on the development of chemical transformations that rely on the formation of electron-donor acceptor (EDA) complexes. Specifically, the enantioselective photochemical perfluoroalkylation of β-ketoesters mediated by a chiral enolate was developed. This study established the ability of chiral enolates, generated under phase transfer (PTC) conditions, to act as suitable donors in the formation of photoactive EDA complexes with perfluoroalkyl iodides, while providing effective asymmetric induction in the generation of quaternary perfluoroalkyl stereogenic centers. The second part of the thesis details a new strategy to design organocatalytic asymmetric cascade processes. The new approach combines the distinct reactivity of two chiral organocatalytic intermediates, namely the excited-state reactivity of chiral iminium ions with the ground-state reactivity of enamines. The photochemical organo-cascade reaction leads to stereochemically dense cyclopentanols with high yields and excellent selectivity, compounds that cannot be accessed by other methods. The observed excellent selectivity originated by an asymmetric amplification mechanism, which is due to a kinetic resolution process operative in the second step of the cascade process.
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Mishir, Qayum. "Enantioselective organocerium reagents." Thesis, University of Liverpool, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.366685.

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Rowland, Emily Bretherick. "Enantioselective Brønsted Acid-Catalyzed Reaction Methodology Part A: Enantioselective Mannich Reaction Part B: Enantioselective Desymmetrization of meso-Aziridines." [Tampa, Fla] : University of South Florida, 2008. http://purl.fcla.edu/usf/dc/et/SFE0002613.

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Sikkander, Mohamed Inthikhab. "Enantioselective synthesis of (+)-majusculone." Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 46 p, 2007. http://proquest.umi.com/pqdweb?did=1253510231&sid=1&Fmt=2&clientId=8331&RQT=309&VName=PQD.

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Wilson, Jonathan E. Ph D. Massachusetts Institute of Technology. "Enantioselective nucleophile-catalyzed cycloadditions." Thesis, Massachusetts Institute of Technology, 2007. http://hdl.handle.net/1721.1/40973.

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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemistry, 2007.
Vita.
Includes bibliographical references.
Chapter 1 describes the development of an asymmetric nucleophile-catalyzed [2+2] cycloaddition of ketenes with aldehydes. This is the first report of a catalytic enantioselective synthesis of trisubstituted [beta]-lactones. Two enantioselective phosphine-catalyzed [3+2] cycloadditions of allenoates are detailed in Chapter 2. A method for the asymmetric synthesis of cyclopentenes via a [3+2] cycloaddition of allenoates with enones is first discussed. This is followed by a report of our efforts to extend this [3+2] methodology to imine electrophiles. We conclude, in Chapter 3, with an account of the development of a novel phosphine-catalyzed synthesis of bicyclo[3.3.0]octanones and bicyclo[4.3.0]nonanones. Preliminary results for an enantioselective variant of this method are also disclosed.
by Jonathan E. Wilson.
Ph.D.
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Boyes, Scott Antony. "Enantioselective synthesis using bromoacetals." Thesis, Sheffield Hallam University, 1998. http://shura.shu.ac.uk/19380/.

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A brief overview of why it is important to prepare a chiral compound as a specific enantiomer rather than as a racemate is discussed along with several general strategies on how they maybe prepared. The area of research into the preparation of racemic and enantiomerically pure arylpropanoic acids is briefly reviewed by reference to some of the more important synthons. Some of the more general procedures that have been developed for the construction of arylpropanoic acids are discussed. The preparation of substituted alkyl aryl ketones and their subsequent two step conversion into diastereomerically enriched dimethyl tartrate (S)-bromoalkyl aryl acetals is described. An investigation into the effects of solvent, source of anhydrous acid, workup procedure, source of bromine and temperature upon the bromination of these dimethyl tartrate acetals is discussed. Direct conversion of these diastereomerically enriched dimethyl tartrate (S)-bromoalkyl aryl acetals into enantiomerically pure (S)-bromoalkyl aryl ketones and their subsequent conversion into (S)-bromoalkyl aryl esters via a Baeyer-Villiger reaction is described. Hydrolysis of these (S)-bromoalkyl aryl esters followed by treatment with diazomethane afforded the corresponding methyl (S)-bromoalkyl esters with minimal racemisation, while treatment of these (S)-bromoalkyl aryl esters with an amine gave the corresponding amide with minimal racemisation. Reduction with sodium borohydride at low temperature of a (S)-bromoalkyl aryl ketone afforded exclusively the corresponding (1S,2S) alkyl aryl bromohydrin as predicted using the Felkin-Anh model. Stereospecific conversion of our diastereomerically enriched dimethyl tartrate (S)-bromoalkyl aryl acetals into (S)-arylcarboxylic acids using a silver promoted or solvent promoted rearrangement is discussed. Subsequent conversion of these (S)-arylcarboxylic acids into the corresponding Boc amide via a modified Curtius rearrangement is described. Possible further uses of dimethyl tartrate bromoacetals leading to the synthesis of highly functionalised lactones, lactols, epoxides, chiral diacids, diamines, chiral ligands, resolving agents etc are also discussed.
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M'BOUNGOU-M'PASSI, ATHANASE. "Tautomerie enantioselective de photoenols." Reims, 1993. http://www.theses.fr/1993REIM5014.

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Au cours de ce travail, nous avons effectue l'irradiation d'un ester alpha,beta-insature a temperature variable, pour rechercher les points isocinetique et d'iso-inversion de la reaction de protonation asymetrique du photodienol. Nous avons aussi developpe une nouvelle voie de synthese asymetrique permettant d'acceder en milieu neutre a des cetones chirales. Selon cette methode, un photoenol est genere a partir d'une cetone aromatique ayant un hydrogene en gamma suivant la reaction de norrish ii. L'induction asymetrique est obtenue par tautomerie de l'enol intermediaire, en presence d'une quantite catalytique d'un inducteur chiral. L'enantioselectivite depend fortement de l'enol, du choix de l'inducteur chiral et des conditions experimentales. Pour acceder a certains inducteurs utilises au cours de ce travail, nous avons propose une methode de synthese efficace permettant d'obtenir l'aminobornanol-endo-endo enantiomoeriquement pur. Differentes methodes developpees dans la litterature ont toujours permis de l'obtenir plus ou moins contamine par ses diastereoisomeres
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Powell, Luke Haydn William. "Palladium-catalysed enantioselective desymmetrisations." Thesis, University of Bath, 2005. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.425803.

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Azzouz, Mariam. "Enantioselective synthesis of natural products." Doctoral thesis, Universitat Rovira i Virgili, 2013. http://hdl.handle.net/10803/365571.

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El objetivo general del trabajo presentado es investigar nuevas metodologías para la síntesis de: a) nectrisina, un inhibidor de α-glucosidasas y α-mannosidasas, b) del fragmento oligosacarídico del antibiótico AT2433-A1, un antibiótico utilizado en el tratamiento de numerosos tipos de cánceres y, c) de análogos del cidofovir o HPMPC, nucleósido acíclico que incorpora una unidad de fosfonato, y que se utiliza en el tratamiento del citomegalovirus (CMV) en pacientes con SIDA. Síntesis enantioselectiva de nectrisina Retrosintéticamente la síntesis de la nectrisina puede llevarse a cabo por ciclación del aminoaldehído 2 (R4=CHO), el cual puede proceder del alqueno trans 3 mediante una reacción de dihidroxilación estereoselectiva. La síntesis de 3 puede llevarse a cabo a partir de 4 mediante elongación de la cadena utilizando la reacción de metatesis cruzada catalizada por rutenio. Finalmente, el intermedio clave 4 procede de una aminación alílica asimétrica catalizada por Pd del monepóxido de butadieno racémico 5, reacción ya descrita por Trost. La aminación alílica asimétrica del monepóxido de butadieno racémico catalizada por Pd (η3-C3H5)PdCl/DACH-naftilo transcurrió con elevado rendimiento y enantioselectividad para dar el compuesto 4. La elongación de la cadena de 4 se realizó mediante una metatesis cruzada catalizada por el catalizador de Grubbs-Hoveyda con diferentes alquenos como acroleína, 2-vinil-1,3-dioxolano, y con acrilato de etilo. Sólo en este último caso se obtuvieron resultados relevantes del compuesto 3 (R4=COOEt) como para continuar la síntesis. La reacción de dihidroxilación estereoselectiva del alqueno trans 3 (R4=COOEt) condujo al diol deseado 2 (R4=COOEt) con buena selectividad utilizando OsO4/TMEDA. La hidrólisis del benzoato con LiOH y la ciclación in situ condujo a la lactama, a partir de la cual se siguió una secuencia sintética descrita en la bibliografía, consistente en la sililación de los grupos hidroxilo, protección del grupo amino en forma de terc-butil carbamato, reducción del carbonilo y eliminación con desprotección concomitante de los grupo sililo para dar la imina, que en nuestras manos no logró llevarse a fin debido a problemas en la última etapa de eliminación para dar la imina. Síntesis enantioselectiva de análogos de Cidofovir HPMPC La síntesis de los análogos del cidofovir se planteó siguiendo un esquema sintético similar al de la nectrisina, en el que la síntesis del intermedio 7 se llevó a cabo mediante la aminación alílica asimétrica del monoepóxido del butadieno y posterior reacción de metátesis cruzada como pasos clave. En primer lugar se realizó la aminación alílica asimétrica catalizada por Pd (η3-C3H5)PdCl/DACH-naftil del monepóxido de butadieno racémico, con adenina y citosina la cual se optimizó hasta conseguir rendimientos y excesos enantioméricos superiores al 90%. Seguidamente se optimizó la reacción de metátesis cruzada de los compuestos obtenidos (6) con un alil fosfonato convenientemente protegido, obteniendo 7 con buen rendimiento. La síntesis de los análogos de cidofovir insaturados 8 y 9 se completó tras la desprotección de todos los grupos protectores con TMSBr. La síntesis del derivado saturado 10 se realizó mediante la hydrogenación (3 bares de hidrógeno, Pd/C durante 5h) y la eliminación de los grupos protectores. Síntesis enantioselectiva del fragmento oligosacarídico del antibiótico AT2433-A1 La retrosíntesis de 18 se planteó por ciclación electrófila inducida por yodo de 15, donde X debiera ser un grupo activador del doble enlace que a su vez se pudiera comportar como grupo saliente en la subsiguiente reacción de glicosilación a partir de 15. La síntesis del intermedio 15 se planteó por diferentes procedimientos y en particular a partir del sulfato 14, el cual provendría del diol 13, que a su vez provendría de la dihidroxilación de 12. El compuesto 12 debería poder obtenerse a partir de 5 por la secuencia clásica de DYKAT y metatesis cruzada. Así, a partir del compuesto 11 (R=Boc) se realizó la metatesis cruzada con diferentes alquenos y en particular con el alil fenil tioéter. Las limitaciones se encontraron en la reacción de dihidroxilación, ya que en casi todos los casos ensayados se produjo la oxidación del azufre, lo que conduciría al cambio de la selectividad en posteriores etapas como la ciclación. Se consiguió evitar la oxidación utilizando ligandos quirales en la dihidroxilación, pero con rendimientos muy bajos no compatibles con un esquema de síntesis por etapas.
The present thesis deals with the development of methodology for the syntheses of several organic molecules that were selected by their interesting biological properties: the antibiotic AT2433-A1, the glycosidase inhibidor nectrisine and analogs of the anti-viral Cidofovir (Figure 1.1) . Although apparently structurally unrelated, they were envisaged to be synthesized through common high-efficient key steps that involve metal-catalyzed process. Enantioselective Synthesis of nectrisine We explore an enantioselective synthesis of nectrisine based on Pd-catalyzed asymmetric allylic amination, cross-metathesis and dihydroxylation as key steps. Scheme 1 shows the retrosynthesis proposed, where the key synthon is the allylamine 4 which is obtained in high enantiomeric purity by a deracemization process using Pd/DACH as a catalytic system. Cross-metathesis will allow increasing the chain length, and at the same time would provide the aldehyde functionality necessary for formation of the cyclic imine moiety in the final nectrisine. Besides, configuration of double bond resulting from cross-metathesis must be E in order to provide the correct configuration of hydroxyl groups in 2 after the dihydroxylation reaction. The stereoselectivity of this reaction will be controlled by the stereocenter in the molecule, which could be also be enhanced by chiral ligands in a matched double stereodifferentiation process. The asymmetric allylic amination from racemic butadiene monoepoxide using (η3-C3H5)PdCl/DACH-naphtyl system and t-Butyl-benzoyl-imido carboxylate as a N-nucleophile proceeded with excellent yield (98%) and enantioselectivity (97%) to obtain the chiral allylic amine synthon 4. Elongation of the chain of the key chiral allylic imide with ethyl acrylate through cross metathesis using Hoveyda-Grubbs catalyst (5 mol %), proceeded quatitatively to obtain the trans alkene intermediates 3. The installation of the syn diol moiety via dihydroxylation of the alkene proceeded with high yield and good diastereoselectivity with OsO4/TMEDA. Hydrolysis of benzoate group in 2 with LiOH and in situ cyclization led to the lactam. Whose hydroxyl functionalities were fully protected by treatment with TBSCl. Subsequent protection with di-t-butyl dicarbonate (Boc) 2O and Et3N in CH2Cl2 gave desired product in 50% yield. The increased carbonyl electrophilicity resulting from NBoc protection should facilitate the smooth reduction of the lactam, which proceeded by reaction with Super Hydride® at −78°C to give lactol. Enantioselective Synthesis of Cidofovir Analogues In this context, the retrosynthetic proposal is shown in Scheme 2. Cidofovir (HPMPC) analogues could be obtained by double bond reduction of product 7 followed by protecting group cleavage on compound 11. Compound 7 in turn can be synthesized from compound 6 via chain elongation mediated by cross-metathesis reaction. Lastly, chiral synthon 6 could be obtained by a palladium-catalyzed dynamic kinetic asymmetric transformation (DYKAT) from racemic butadiene monoepoxide (5). The asymmetric allylic amination of racemic butadiene monoepoxide with cytosine as N-nucleophile was carried out with (η3-C3H5)PdCl/DACH-naphtyl system to obtain chiral allylic cytosine in 85% yield and 72% ee. The reaction was successfully expanded to other pyrimidine and purine bases, among which adenine afforded chiral allyl adenine in 90% yield and 92% ee. Chain elongation via Ru-cross metathesis of key allylic nucleobases and diethyl allylphosphonate with second generation Grubbs catalyst (5 mol%), produced desired compounds in 92% and 90% yield, respectively. Deprotection of all protecting groups with TMSBr afforded the desired unsaturated acyclic nucleosides 8 and 9 in good yields. Hydrogenation with (H2, /Pd/C) at 3 bar rendered the saturated Cidifovir analogues 10. Approaches to the Enantioselective Synthesis of AT2433-A1 The objective of this work was to explore a new enantioselective method to obtain AT2433-A1 with special focus on the synthesis of the 2, 4-dideoxy-4-amino-xyloside moiety. The retrosynthetic proposal is shown in Scheme 5.6. The aminodeoxysugar (19) could be obtained from 16 by eletrophile-induced cyclization. A key point is the selection of group X, since it must control the regioselectivity of the cyclization to an endo-mode and eventually must behave as a leaving group in a future glycosylation reaction. Amino alcohol 16 could be prepared from allylic amine 13 by dihydroxylation, sulphate formation and elimination. Compound 13 can be synthesized from allyl amine 12 via chain elongation mediated by cross-metathesis reaction. Lastly, chiral allyl amine 12 could be obtained, similarly to the previous chapters, by a palladium-catalyzed dynamic kinetic asymmetric transformation (DYKAT) from the racemic butadiene monoepoxide 5. On the other hand, the intermediate 15 could be also obtained by addition to the Garner aldehyde (18) followed by deprotection of the protecting groups in 17. The asymmetric allylic amination from racemic butadiene monoepoxide using (η3-C3H5)PdCl/DACH-naphtyl system and imide as a nitrogen nucleophile proceeded with good yield (96%) and enantioselectivity (90%). Chain elongation of key chiral allylic amine 12 was carried out by cross metathesis with allyl phenyl sulphide with Hoveyda-Grubbs catalyst (5 mol%) to obtain the corresponding trans alkene 13 in 80% yield. The installation of the diol moiety with OsO4 was unsuccesful, due to the competitive oxidation of sulfur, preventing the completion of the synthesis.
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Gauvreau, Danny. "Enantioselective tandem oxy-copeene reaction." Thesis, University of Ottawa (Canada), 2003. http://hdl.handle.net/10393/26374.

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The tandem oxy-Cope/ene reaction allows the rapid construction of complex structures in a few steps. It was notably used in the total synthesis of (+)-arteannium M where the cascade revealed to be highly diastereoselective and enantioselective. The hypothesis that the retention of chirality based on the rigidity of an intermediate atropisomer devoid of stereogenic centers was proposed. This document presents a study of the enantioselectivity of the tandem oxy-Cope/ene reaction and provides an explanation for the decrease in chirality observed during the cascade. Different variables of the reaction and of the starting material were analyzed to explain the retention of chirality.* The efforts of our group in the development of tandem reactions led to the discovery of a novel cascade that involves 4 pericyclic reactions: the oxa-Cope/Claisen/ene/Claisen cascade. This sequence of reactions was briefly investigated to determine its scope and limitations, notably by changing the substituent on the alkyne and on the tertiary alcohol of 150*. *Please refer to dissertation for diagrams.
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Books on the topic "Enantioselective"

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KLABUNOVSKII, EVGENII, GERARD V. SMITH, and ÁGNES ZSIGMOND, eds. HETEROGENEOUS ENANTIOSELECTIVE HYDROGENATION. Dordrecht: Springer Netherlands, 2006. http://dx.doi.org/10.1007/978-1-4020-4296-6.

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Dalko, Peter I., ed. Comprehensive Enantioselective Organocatalysis. Weinheim, Germany: Wiley-VCH Verlag GmbH & Co. KGaA, 2013. http://dx.doi.org/10.1002/9783527658862.

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Cox, Geoffrey B., ed. Preparative Enantioselective Chromatography. Oxford, UK: Blackwell Publishing Ltd, 2005. http://dx.doi.org/10.1002/9780470988428.

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Nevanen, Tarja K. Enantioselective antibody fragments. [Espoo, Finland]: VTT Technical Research Centre of Finland, 2004.

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1952-, Cox Geoffrey J., ed. Preparative enantioselective chromatography. Ames, Iowa: Blackwell Pub., 2005.

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Mahrwald, Rainer. Enantioselective Organocatalyzed Reactions I: Enantioselective Oxidation, Reduction, Functionalization and Desymmetrization. Dordrecht: Springer Science+Business Media B.V., 2011.

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Sebesta, Radovan, ed. Enantioselective Homogeneous Supported Catalysis. Cambridge: Royal Society of Chemistry, 2011. http://dx.doi.org/10.1039/9781849733427.

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Hodgson, David M., ed. Organolithiums in Enantioselective Synthesis. Berlin, Heidelberg: Springer Berlin Heidelberg, 2003. http://dx.doi.org/10.1007/3-540-36117-0.

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Mahrwald, Rainer, ed. Enantioselective Organocatalyzed Reactions I. Dordrecht: Springer Netherlands, 2011. http://dx.doi.org/10.1007/978-90-481-3865-4.

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Mahrwald, Rainer, ed. Enantioselective Organocatalyzed Reactions II. Dordrecht: Springer Netherlands, 2011. http://dx.doi.org/10.1007/978-90-481-3867-8.

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Book chapters on the topic "Enantioselective"

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Normant, Jean F. "Enantioselective Carbolithiations." In Organolithiums in Enantioselective Synthesis, 287–310. Berlin, Heidelberg: Springer Berlin Heidelberg, 2003. http://dx.doi.org/10.1007/3-540-36117-0_9.

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Uzir, Mohamad Hekarl. "Enantioselective Synthesis." In Encyclopedia of Membranes, 700. Berlin, Heidelberg: Springer Berlin Heidelberg, 2016. http://dx.doi.org/10.1007/978-3-662-44324-8_2070.

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Uzir, Mohamad Hekarl. "Enantioselective Membrane." In Encyclopedia of Membranes, 699. Berlin, Heidelberg: Springer Berlin Heidelberg, 2016. http://dx.doi.org/10.1007/978-3-662-44324-8_2072.

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Coote, Susannah C., and Thorsten Bach. "Enantioselective Photocatalysis." In Visible Light Photocatalysis in Organic Chemistry, 335–61. Weinheim, Germany: Wiley-VCH Verlag GmbH & Co. KGaA, 2018. http://dx.doi.org/10.1002/9783527674145.ch11.

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Uzir, Mohamad Hekarl. "Enantioselective Synthesis." In Encyclopedia of Membranes, 1–2. Berlin, Heidelberg: Springer Berlin Heidelberg, 2015. http://dx.doi.org/10.1007/978-3-642-40872-4_2070-1.

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Uzir, Mohamad Hekarl. "Enantioselective Membrane." In Encyclopedia of Membranes, 1. Berlin, Heidelberg: Springer Berlin Heidelberg, 2015. http://dx.doi.org/10.1007/978-3-642-40872-4_2072-1.

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Kotsuki, Hiyoshizo, and Niiha Sasakura. "Proline-Related Secondary Amine Catalysts and Applications." In Comprehensive Enantioselective Organocatalysis, 1–31. Weinheim, Germany: Wiley-VCH Verlag GmbH & Co. KGaA, 2013. http://dx.doi.org/10.1002/9783527658862.ch1.

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Türkmen, Yunus E., Ye Zhu, and Viresh H. Rawal. "Brønsted Acids." In Comprehensive Enantioselective Organocatalysis, 239–88. Weinheim, Germany: Wiley-VCH Verlag GmbH & Co. KGaA, 2013. http://dx.doi.org/10.1002/9783527658862.ch10.

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Mori, Keiji, and Takahiko Akiyama. "Brønsted Acids: Chiral Phosphoric Acid Catalysts in Asymmetric Synthesis." In Comprehensive Enantioselective Organocatalysis, 289–314. Weinheim, Germany: Wiley-VCH Verlag GmbH & Co. KGaA, 2013. http://dx.doi.org/10.1002/9783527658862.ch11.

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Jakab, Gergely, and Peter R. Schreiner. "Brønsted Acids: Chiral (Thio)urea Derivatives." In Comprehensive Enantioselective Organocatalysis, 315–41. Weinheim, Germany: Wiley-VCH Verlag GmbH & Co. KGaA, 2013. http://dx.doi.org/10.1002/9783527658862.ch12.

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Conference papers on the topic "Enantioselective"

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Eames, Jason, Ewan Boyd, Alastair Hay, Ray Jones, Rachel Stenson, and Michael Suggate. "Enantioselective Protonation of Prostereogenic Enol Equivalents." In The 10th International Electronic Conference on Synthetic Organic Chemistry. Basel, Switzerland: MDPI, 2006. http://dx.doi.org/10.3390/ecsoc-10-01388.

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Bagnoli, Luana, Marcello Tiecco, Lorenzo Testaferri, Catalina Scarponi, Andrea Temperini, Francesca Marini, and Claudio Santi. "Selenium Promoted Enantioselective Synthesis of Spiroketals." In The 9th International Electronic Conference on Synthetic Organic Chemistry. Basel, Switzerland: MDPI, 2005. http://dx.doi.org/10.3390/ecsoc-9-01519.

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Carrillo Fernández, Luisa, Jose Luis Vicario, Iker Riaño, Estibaliz Diaz, Efraim Reyes Martín, and Uxue Uria. "Enantioselective Synthesis of Chiral Proline Derivatives." In MOL2NET 2016, International Conference on Multidisciplinary Sciences, 2nd edition. Basel, Switzerland: MDPI, 2016. http://dx.doi.org/10.3390/mol2net-02-h004.

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Barabás, Béla, Luciano Caglioti, Francesco Faglioni, Nicola Florini, Paolo Lazzeretti, Marco Maioli, Károly Micskei, et al. "On the Traces of Absolute Enantioselective Synthesis." In COMPUTATIONAL METHODS IN SCIENCE AND ENGINEERING: Theory and Computation: Old Problems and New Challenges. Lectures Presented at the International Conference on Computational Methods in Science and Engineering 2007 (ICCMSE 2007): VOLUME 1. AIP, 2007. http://dx.doi.org/10.1063/1.2835949.

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Avetisov, Vladik A. "Spontaneous mirror symmetry breaking via enantioselective autocatalysis." In Physical orgin of homochirality in life. AIP, 1996. http://dx.doi.org/10.1063/1.51238.

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Yamada, Tohru. "Microwave Specific Effect on Catalytic Enantioselective Reactions." In 2018 Asia-Pacific Microwave Conference (APMC). IEEE, 2018. http://dx.doi.org/10.23919/apmc.2018.8617203.

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Cahard, Dominique, Jun-An Ma, and Vitaliy Petrik. "Towards Enantioselective Electrophilic Trifluoromethylation of β-Keto Esters." In The 10th International Electronic Conference on Synthetic Organic Chemistry. Basel, Switzerland: MDPI, 2006. http://dx.doi.org/10.3390/ecsoc-10-01405.

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Cahard, Dominique, Christophe Audouard, Jérôme Baudoux, Barbara Mohar, and Jean-Christophe Plaquevent. "Enantioselective Electrophilic Fluorination : Two Approaches Using Cinchona Alkaloids." In The 4th International Electronic Conference on Synthetic Organic Chemistry. Basel, Switzerland: MDPI, 2000. http://dx.doi.org/10.3390/ecsoc-4-01862.

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LEI, JIAN-DU, and TIAN-WEI TAN. "ENANTIOSELECTIVE SEPARATION OF RACEMIC KETOPROFEN USING MOLECULAR IMPRINTING." In Proceedings of the 4th International Conference. WORLD SCIENTIFIC, 2004. http://dx.doi.org/10.1142/9789812702623_0143.

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Li, Zhaoyang, Ye Zhang, Xiangnan Luo, Fengning Cheng, Jie Guo, and Weixiao Wang. "Enantioselective Degradation and Chiral Stability of Profenophos in Soils." In 2010 4th International Conference on Bioinformatics and Biomedical Engineering (iCBBE). IEEE, 2010. http://dx.doi.org/10.1109/icbbe.2010.5518046.

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Reports on the topic "Enantioselective"

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Zagitova, Liana, Ilya Abramov, and Svetlana Gainanova. Levofloxacin enantioselective voltammetric sensing based on functionalized fullerene. Peeref, July 2023. http://dx.doi.org/10.54985/peeref.2307p8077405.

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Ray, Sayan, Biki Ghosh, and Santanu Mukherjee. Centrally Chiral Arenes: From Concept to Catalytic Enantioselective Synthesis. The Israel Chemical Society, March 2023. http://dx.doi.org/10.51167/acm00037.

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Joshi, N. N., M. Srebnik, and H. C. Brown. Chiral Oxazaborolidines as Catalysts for the Enantioselective Addition of Diethylzinc to Aldehydes. Fort Belvoir, VA: Defense Technical Information Center, July 1989. http://dx.doi.org/10.21236/ada210543.

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Nazyrov, Marat, and Yulia Yarkaeva. Enantioselective voltammetric sensor system based on mesoporous carbon black Carbopack X and cyclopentadiene derivatives for determination of clopidogrel enantiomers. Peeref, July 2023. http://dx.doi.org/10.54985/peeref.2307p5734071.

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