Dissertationen: „Allyic substitution“

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Yu, Xiaodan. „New functionalized alkylidenecyclobutanes : multicomponent synthesis and applications“. Electronic Thesis or Diss., université Paris-Saclay, 2024. http://www.theses.fr/2024UPASF034.

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Les dérivés du cyclobutane sont devenus de plus en plus importants en tant que blocs de construction moléculaires en raison de leur contrainte cyclique inhérente et de la modification sélective de leurs structures qui peuvent être utilisées de manière stratégique dans la synthèse organique. Les cycles cyclobutane apparaissent également dans les structures moléculaires d'un large panel de molécules naturelles et synthétiques qui présentent des activités biologiques intéressantes. Au sein de cette grande famille, les sous-unités alkylidènecyclobutane sont rencontrées dans des produits naturels, tels que la providencine, et elles présentent une réactivité accrue permettant d'accéder à des structures moléculaires complexes, notamment des dérivés cyclobutane à cycle élargi et hautement fonctionnalisés. Dans notre laboratoire, nous avons récemment développé une synthèse efficace de cyclobutènes fonctionnalisés par une réaction domino photochimique à partir de cyclopent-2-énones et d'éthylène. Sur la base de cette étude, nous avons d'abord exploré une transformation simple de cyclobutènes fonctionnalisés en alkylidènecyclobutanes. Ensuite, nous avons combiné les deux séquences dans un processus domino à plusieurs composants. La réaction domino-MCR est réalisée selon un protocole unique, comprenant une réaction photochimique en tandem de cycloaddition [2+2] / Norrish-I / γ-H suivie d'une réaction de protection acétal et d'une réaction de substitution allylique. De plus, la version intramoléculaire de ces réactions a permis la synthèse d'alkylidènecyclobutanes bicycliques fusionnés complexes. Enfin, la post-fonctionnalisation des alkylidènecyclobutanes a été étudiée, dans le but de découvrir le nouveau composé tricyclique fusionné par un processus photochimique intramoléculaire [2+2]
Cyclobutane derivatives have become increasingly important as molecular building blocks because of their inherent ring strain that facilitates the selective modification of their structures for strategic used in organic synthesis. Cyclobutane rings also appear in the molecular structures of a wide panel of natural and synthetic molecules that display interesting biological activities. Within this large family, alkylidenecyclobutane subunits are encountered in natural products, such as providencin, and they exhibit enhanced reactivity providing access to complex molecular structures, including enlarged ring and highly functionalized cyclobutane derivatives. In our laboratory, we recently developed an efficient synthesis of functionalized cyclobutenes through a domino photochemical reaction starting from cyclopent-2-enones and ethylene. Based on this study, we first explored a straight-forward transformation of functionalized cyclobutenes into alkylidenecyclobutanes. We then combined both sequences in a domino-multicomponent process. This was accomplished in a single protocol, comprising a tandem photochemical [2+2]-cycloaddition / Norrish-I / γ-H transfer reaction followed by an acetal-protection and an allylic substitution reaction. Additionally, the intramolecular version of these reactions allowed the synthesis of complex fused-bicyclic alkylidenecyclobutanes. Finally, the post-funtionalization of selected alkylidenecyclobutanes was studied, aiming to prepare novel fused tricyclic compounds through a intramolecular [2+2] photochemical process

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2

Xie, Jianing. „Advancing Pd-catalyzed Stereoselective Allylic Substitution Reactions“. Doctoral thesis, Universitat Rovira i Virgili, 2020. http://hdl.handle.net/10803/670221.

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Aquesta tesi doctoral se centra principalment en el desenvolupament de nous mètodes catalítics (dòmino) basats en la substitució al·lílica catalitzada per Pd per a la síntesi estereoselectiva de petites molècules funcionals i heterocicles utilitzant un disseny detallat de lligants i substrats. Aquesta tesi està organitzada en cinc capítols: el primer capítol és una introducció general sobre els aspectes bàsics de la química al·lílica. El segon capítol il·lustra el primer mètode general per a la preparació d'èters arílics al·lílics terciaris enantioenriquits mitjançant una eterificación regio- i enantio-selectiva catalitzada per Pd dels VCCs en presència de nucleòfils fenòlics. La regioselectivitat de la reacció pot ajustar-se selectivament al producte lineal Z canviant el lligant fosforamidit a un lligant monofosfina, demostrant així el paper crucial del disseny adequat del lligant. El tercer capítol descriu el disseny d'un nou alcohol al·lílic terciari equipat amb un grup carboxil, que s'utilitza en primer lloc per a la síntesi de γ-lactames α,β-insaturades mitjançant una aminació al·lílica estereoselectiva catalitzada per Pd, seguit d’un procés de ciclació intramolecular. Els estudis mecanístics suggereixen que el grup carboxil és crucial per a aquesta transformació i actua com un grup funcional activador i estereodirector. El quart capítol presenta un enfocament estereodivergent controlat pel lligant per a la síntesi de γ-aminoàcids amb configuració Z o E derivats d'alcohols al·lílics terciaris i amines secundàries. Els resultats experimentals destaquen el paper crucial del lligant de suport i l'angle de mossegada de la difosfina. El cinquè capítol informa sobre un mètode general per a la síntesi de caprolactames insaturades substituïdes a través d'un procés d'aminació / ciclació en cascada utilitzant vinil γ-lactones com a substrats mitjançant l'ús d'un lligant fosforamidito recentment desenvolupat. Finalment, s'extreu una conclusió general per a cada capítol i també es discuteix l’aplicació potencial d'aquestes metodologies desenvolupades.
Esta tesis doctoral se centra principalmente en el desarrollo de nuevos métodos catalíticos (dominó) basados en la sustitución alílica catalizada por Pd para la síntesis estereoselectiva de pequeñas moléculas funcionales y heterociclos utilizando un diseño detallado de ligandos y sustratos. Esta tesis está organizada en cinco capítulos: el primer capítulo es una introducción general sobre los aspectos básicos de la química alílica. El segundo capítulo ilustra el primer método general para la preparación de éteres arílicos alílicos terciarios enantioenriquecidos mediante una eterificación regio- y enantio-selectiva catalizada por Pd de los VCCs en presencia de nucleófilos fenólicos. La regioselectividad de la reacción puede ajustarse selectivamente al producto lineal Z cambiando el ligando fosforamidito a un ligando monofosfina, demostrando así el papel crucial del diseño adecuado del ligando. El tercer capítulo describe el diseño de un nuevo alcohol alílico terciario equipado con un grupo carboxilo, que se utiliza en primer lugar para la síntesis de γ-lactamas α,β-insaturadas mediante una aminación alílica estereoselectiva catalizada por Pd, seguido por un proceso de ciclación intramolecular. Los estudios mecanisticos sugieren que el grupo carboxilo es crucial para esta transformación y actúa como un grupo funcional activador y estereodirector. El cuarto capítulo presenta un enfoque estereodivergente controlado por el ligando para la síntesis de γ-aminoácidos con configuración Z o E derivados de alcoholes alílicos terciarios y aminas secundarias. Los resultados experimentales destacan el papel crucial del ligando de soporte y el ángulo de mordedura de la difosfina. El quinto capítulo informa sobre un método general para la síntesis de caprolactamas insaturadas sustituidas a través de un proceso de aminación / ciclación en cascada utilizando vinil γ-lactonas como sustratos mediante el uso de un ligando fosforamidito recientemente desarrollado. Finalmente, se extrae una conclusión general para cada capítulo y también se discute la aplicación potencial de estas metodologías desarrolladas.
This doctoral thesis is mainly focused on the development of novel catalytic (domino) synthesis methods based on Pd-catalyzed allylic substitution for the stereoselective synthesis of functional small molecules and heterocycles utilizing a detailed ligand engineering and substrate design. The scope of this thesis is organized into five chapters: the first chapter is a general introduction on the regular aspects of allylic chemistry. The second chapter illustrates the first general method for the preparation of enantioenriched tertiary allylic aryl ethers through a Pd-catalyzed regio- and enantio-selective etherification of VCCs in the presence of phenolic nucleophiles. The regioselectivity of the reaction can be finely tuned to the Z-selective linear product by switching the phosphoramidite ligand to a monophosphine ligand, thus proving the crucial role of proper ligand engineering. The third chapter describes a newly designed tertiary allylic alcohol equipped with a carboxyl group, which is firstly used for α,β-unsaturated γ-lactams synthesis through Pd-catalyzed stereoselective allylic amination and intramolecular cyclization process. Mechanistic studies suggest that the carboxyl group is crucial for this transformation, and acts as an activating and stereodirecting functional group. The fourth chapter presents a ligand-controlled stereodivergent approach for the synthesis of either Z or E-configured γ-amino acids derived from tertiary allylic alcohols and secondary amines. The experimental results highlight the crucial role of the supporting ligand and the diphosphine bite angle. The fifth chapter reports a general method for substituted unsaturated caprolactam synthesis through a cascade amination/cyclization process using vinyl γ-lactones as substrate by using a newly developed phosphoramidite ligand. Finally, a general conclusion for each chapter is given and potential applications for these developed methodologies are also discussed.

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Clizbe, Elizabeth Adair. „Assymmetric transition metal-catalyzed allylic substitution reactions“. Thesis, University of Liverpool, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.539737.

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4

Cai, Aijie. „Pd-catalyzed Allylic Substitution for Construction of Quaternary Stereocenters“. Doctoral thesis, Universitat Rovira i Virgili, 2019. http://hdl.handle.net/10803/668819.

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Des del primer treball inicial de Tsuji i Trost, hi ha hagut un ràpid progrés durant les últimes dècades en el desenvolupament de lligands quirals i l'abast de reacció dels electròfils i nucleòfils aplicables en reaccions de substitució al·lílica catalitzades per Pd. A més, s'han utilitzat reaccions de substitució al·lílica asimètriques asimètriques catalitzades per Pd en la síntesi total d'una varietat de molècules quirals complexes, proporcionant una evidència sòlida de la utilitat de la metodologia AAA en el control tant de la regio com de l'enantio-selectivitats. Malgrat els nombrosos avenços ja realitzats, forjar derivats al·lílics ramificats quirals de materials inicials senzills i fàcilment disponibles continua essent una tasca important en la química sintètica, a causa del potencial d’aquests compostos al·lílics quirals en campanyes postintèntiques. Les bastides al·líliques que porten estereocentrisme quaternari basades en reaccions de substitució al·lílica catalitzades per Pd encara no es troben en cap cas. en aquesta tesi, hem desenvolupat una metodologia eficient i concisa per a la síntesi d’amines al·líliques aral a-a-desubstituïdes amb alts nivells de regio i enantioselectivitat. A continuació, vam desbloquejar l’origen de la regio- i l’enantioselectivitat en la inusual aminació al·lílica mitjançant càlculs de la teoria funcional de densitat (DFT) en combinació amb experiments de control mecanicista. Finalment, es van dissenyar lligams quirials nous i eficients i el seu ús en la síntesi en regio- i enantioselectiva de catalitzats de Pd de sulfones al·líliques ramificades. La utilitat del mètode es demostrarà més mitjançant la síntesi del sesquiterpè (-) - Agelasidine A.
Des del primer treball inicial de Tsuji i Trost, hi ha hagut un ràpid progrés durant les últimes dècades en el desenvolupament de lligands quirals i l'abast de reacció dels electròfils i nucleòfils aplicables en reaccions de substitució al·lílica catalitzades per Pd. A més, s'han utilitzat reaccions de substitució al·lílica asimètriques asimètriques catalitzades per Pd en la síntesi total d'una varietat de molècules quirals complexes, proporcionant una evidència sòlida de la utilitat de la metodologia AAA en el control tant de la regio com de l'enantio-selectivitats. Malgrat els nombrosos avenços ja realitzats, forjar derivats al·lílics ramificats quirals de materials inicials senzills i fàcilment disponibles continua essent una tasca important en la química sintètica, a causa del potencial d’aquests compostos al·lílics quirals en campanyes postintèntiques. Les bastides al·líliques que porten estereocentrisme quaternari basades en reaccions de substitució al·lílica catalitzades per Pd encara no es troben en cap cas. en aquesta tesi, hem desenvolupat una metodologia eficient i concisa per a la síntesi d’amines al·líliques aral a-a-desubstituïdes amb alts nivells de regio i enantioselectivitat. A continuació, vam desbloquejar l’origen de la regio- i l’enantioselectivitat en la inusual aminació al·lílica mitjançant càlculs de la teoria funcional de densitat (DFT) en combinació amb experiments de control mecanicista. Finalment, es van dissenyar lligams quirials nous i eficients i el seu ús en la síntesi en regio- i enantioselectiva de catalitzats de Pd de sulfones al·líliques ramificades. La utilitat del mètode es demostrarà més mitjançant la síntesi del sesquiterpè (-) - Agelasidine A.
Since the early seminal work by J. Tsuji and B. M. Trost, there has been rapid progress in the development of chiral ligands and scope of the electrophiles and nucleophiles in Pd-catalyzed allylic substitution reactions over the past few decades. In addition, Pd-catalyzed asymmetric allylic substitution reactions have been applied in total synthesis of a variety of complex chiral molecules, providing solid evidence of the efficiency of this methodology in controlling both regio- and enatioselectivities. Despite the numerous advances realized, forging chiral branched allylic derivatives from simple and readily available starting materials continues to be an important task in synthetic chemistry, due to the potential of the allylic moiety for further elaboration and asymmetric synthesis. The building allylic scaffolds bearing quaternary stereocenters based on Pd-catalyzed allylic substitution still remain rather underexplored. In this thesis, we have develop a concise and efficient methodology for synthesis of chiral a,a-disubtituted allylic amines with high levels of regio- and enantioselectivity. And then, we unlocked the origin of the regio- and enantioselectivity in the unusual allylic amination by density functional theory (DFT) calculations in combination with mechanistic control experiments.Finally, we designed a novel and highly efficient ligand to mediate regio- and enantioselective synthesis of various chiral allylic sulfones featuring quaternary stereocenters. The utility of the method will be further demonstrated by the synthesis of the sesquiterpene (-)-Agelasidine A.

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Takeda, Momotaro. „Copper-Catalyzed Asymmetric Allylic Substitution with Organo- and Silylboronates“. 京都大学 (Kyoto University), 2014. http://hdl.handle.net/2433/188504.

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6

Baldwin, I. Craig. „New methodology involving allylic substitution and conjugate addition reactions“. Thesis, Loughborough University, 1996. https://dspace.lboro.ac.uk/2134/27583.

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Chapter one reviews routes to the generation of α-aminophosphonates and α-aminophosphonic acids. These biologically important compounds are synthesised in both racemic and enantiomerically enriched forms. The second chapter describes the results of conjugate addition reactions of lower order cuprates to diethylvinylphosphonate followed by an electrophilic quench to give a range of alkylphosphonates. The third and fourth chapters are concerned with the generation of enantiomencally enriched α-aminophosphonates and α-aminoesters via palladium catalysed allylic substitution reactions With allyl acetate the resulting products were isolated with an enantiomeric excess of up to 19%. With 1,3-diphenyl-2-propenyl acetate products with both high diastereomeric and enantiomeric excesses were isolated with the best being 75 % de and 97 % ee.

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Dawson, Graham John. „Studies on the stereoselective palladium-catalysed allylic substitution reaction“. Thesis, Loughborough University, 1995. https://dspace.lboro.ac.uk/2134/31866.

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This thesis contains the preparation of a new design of ligand for the palladium catalysed allylic substitution reaction. The phosphine oxazoline ligands detailed in the thesis give high levels of enantiocontrol when used in conjunction with symmetrical allyl systems in the palladium catalysed allylic substitution reaction. For unsymmetrical allyl systems the palladium catalysed allylic substitution process proceeds with complete regiocontrol and high levels of stereocontrol are again observed. The products from the palladium catalysed allylic substitution reaction can be readily converted to succinic acids, γ-lactones and aryl propanoic acids.

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Tosatti, Paolo. „Metal-catalysed asymmetric allylic substitution reactions for array synthesis“. Thesis, University of Leeds, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.540583.

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9

Kawatsura, Motoi. „Palladium-Catalyzed Allylic Substitution with a Monodentate Phosphine Ligand“. 京都大学 (Kyoto University), 1998. http://hdl.handle.net/2433/157157.

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本文データは平成22年度国立国会図書館の学位論文(博士)のデジタル化実施により作成された画像ファイルを基にpdf変換したものである
Kyoto University (京都大学)
0048
新制・課程博士
博士(理学)
甲第7163号
理博第1937号
新制||理||1043(附属図書館)
UT51-98-G92
京都大学大学院理学研究科化学専攻
(主査)教授林民生, 教授鈴木仁美, 教授大須賀篤弘
学位規則第4条第1項該当

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10

Ceban, Victor. „New methodologies in asymmetric allylic substitution and organocascade reactions“. Thesis, University of Southampton, 2015. https://eprints.soton.ac.uk/397983/.

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Asymmetric organocatalysis and organometallic catalysis are rapidly developing. The first catalytic process can be traced back in the XIX century. Since then, research in the field of catalysis grew, especially in the last decades exponentially. Four projects involving organocatalysis are described in this thesis: “Highly enantioselective addition of anthrones to MBH-carbonates”, “Synergistic catalysis: Highly diastereoselective benzoxazole addition to Morita-Baylis-Hillman carbonates”, “Three-component diastereoselective cascade synthesis of thiohydantoins” and “Highly diastereoselective synthesis of spiropyrazolones”. A) Asymmetric allylic substitution Since Tsuji and Trost reported their first examples of allylic substitution catalysed by palladium salts in 1963, many examples of allylic substitution were published involving other types of transition metals. Later, in 2002, Kim et al. reported the first allylic substitution using a metal-free approach. Morita-Baylis-Hillman carbonates are important scaffolds in the synthesis of more complex molecules due to the presence of numerous functional groups. In this thesis two examples of asymmetric allylic substitution involving Morita-Baylis-Hillman (MBH) carbonates are described. Highly enantioselective addition of anthrones to Morita-Baylis-Hillman carbonates Anthrone derivatives are present in various natural sources and are known for their medicinal effects. We were interested in the enantioselective addition of anthrone to MBH-carbonates. The products were synthesised in very good yields and enantioselectivity by using a (DHQD)2AQN as catalyst. Moreover, a kinetic resolution was perfomed in order to better understand the mechanistic process. Synergistic catalysis: Highly diastereoselective benzoxazole addition to Morita-Baylis-Hillman carbonates Catalysis is one of the most efficient strategies for identifying new chemical reactions. Usually, a catalytic pathway relies on the interaction of a single catalyst with a single reagent in order to lower the energetic barrier. In some cases, the mono-catalytic concept is not enough and other strategies are used, in particular, synergistic catalysis. This consists in the activation of the electrophile and the nucleophile by two different catalysts for reaction to occur. Based on this idea, we studied the addition of benzoxazoles to Morita-Bayllis-Hillman carbonates by the use of two different catalysts (Metal Lewis acid and Organic Lewis base). Both catalysts work in a concerted way giving the final compound in high yield and diastereoselectivity. B) Organocascade reactions Synthesis of complex organic molecules is a challenge for every chemist. The aim is achieveing the final product in as few steps as possible using safer, cleaner and environmentally friendly techniques. One-pot reactions emerged as a powerful tool in creating several bonds in one step. Based on this idea, we studied two reactions: Three-component diastereoselective cascade synthesis of thiohydantoins Thiohydantoins have interesting medicinal applications such as antibacterial, antiviral, antimutagenic, etc. Synthesising these scaffolds in one step via three-component one-pot reaction was our main focus. We developed a three-component cascade reaction for the synthesis of thiohydantoins. The reaction between ?-amino esters, nitrostyrenes and aromatic isothiocyanates is efficiently promoted by organic bases to afford highly substituted thiohydantoins in moderate to good yields and diastereoselectivities. Highly diastereoselective synthesis of spiropyrazolones Spiro compounds are present in various natural products and are powerful active agents. We have developed a methodology for the synthesis of spiropyrazolone bearing fourchiral centres. The reaction was catalysed by a secondary amine in a Michael-aldol cascade fashion affording the product in very good yields and diastereoselectivity.

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Popa, Dana Madeleine. „Modular phosphinooxazolines: synthesis and evaluation in allylic substitutions“. Doctoral thesis, Universitat Rovira i Virgili, 2008. http://hdl.handle.net/10803/9025.

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La reacción de substitución alílica asimétrica representa un método importante para la generación de enlaces C-C y C-N de forma estereoselectiva (Esquema 1).
Las fosfinooxazolinas (Figura 1) fueron descritas originalmente en 1993 por Pfaltz Williams y Helmchen1 de simultáneamente y han sido utilizadas en múltiples ejemplos de sustituciones alílicas enantioselectivas sobre una gran diversidad de sustratos.
En el primer capitulo de la Tesis, se recoge la síntesis y caracterización de una familia altamente modular de complejos de paladio-fosfinooxazolina. La metodología de síntesis empleada se describe en el Esquema 1.
La preparación de los epoxiéteres 1a-e a partir del epoxido de Sharpless ha sido descrita con anterioridad en nuestro grupo de trabajo.2 La apertura regioselectiva y estereoespecífica de los epoxiéteres con amoniaco (25% NH3 en solución acuosa, en tubo de presión o en condiciones de irradiación en microondas) ha conducido a los amino alcoholes enantiopuros 2a-e los cuales, sin previa purificación, han sido Nacilados seguido de activación del hidroxilo (como mesilato) y ciclación resultando las fluorooxazolinas 5a-e. En el siguiente paso, la substitución del átomo de flúor por derivados de fósforo aniónicos ha conducido a los ligandos fosfinooxazolina que finalmente han sido transformados en los complejos de paladio 7a-e. Los métodos preparativos empleados son fácilmente escalables y ha sido posible obtener con suma facilidad, en algunos casos, cantidades cercanas al gramo. En el segundo capítulo de la Tesis están recogidos los resultados obtenidos en la alquilación alílica mediada por la nueva familia de complejos [Pd(η3-alil)(PHOX)]PF6 7a-e. Los complejos descritos en este trabajo han mostrado una gran estereoselectividad en un amplio margen de temperaturas, sin prácticamente ninguna pérdida en la enantioselectividad en el rango de temperaturas comprendido entre temperatura ambiente y 130º C. En la Tabla 1 se resumen las mejores condiciones de reacción optimizadas para la alquilación alílica asimétrica de una serie de acetatos alílicos con nucleófilos derivados de ésteres malónicos. Se ha observado un caso sin precedentes de inversión de la enantioselectividad para el acetato de 1,3-dimetilalílo comparado con el substrato análogo difenil sustituído.
En el tercer capítulo de la Tesis están recogidos los resultados obtenidos con la nueva familia de complejos Pd-PHOX en la aminacion asimétrica de varios substratos alílicos con nucleófilos nitrogenados. El grado de estereoinducción alcanzado con nuestros ligandos, en algunos de los casos, ha sido superior a los resultados descritos en la literatura. En la tabla 2 se resumen las mejores condiciones de reacción desarrolladas para la aminación alílica asimétrica de una serie de acetatos alílicos con una gran variedad de nucleófilos nitrogenados.
En el cuarto capítulo presentamos un nuevo agente chiral de resolucion, para la determinación de la pureza óptica de aminas quirales. Las aminas primarias y secundarias fueron derivatizadas con el reactivo quiral por apertura del agente de resolución (fluoro epóxido 8) resultando en la formación de productos diastereoméricos los cuales son fáciles de identificar y cuantificar mediante 19F, 1H, 13C NMR y HPLC (Esquema 2).

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Béton, Didier. „Synthesis of new phosphorus amidite ligands : iridium-catalyzed allylic substitution /“. Heidelberg, 2008. http://opac.nebis.ch/cgi-bin/showAbstract.pl?sys=000253233.

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13

Litvinov, Alexander E. „Ortho-diphenylphosphanylbenzoyl-directed Palladium catalyzed allylic substitution with soft nucleophiles“. [S.l. : s.n.], 2008. http://nbn-resolving.de/urn:nbn:de:bsz:25-opus-61462.

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14

Perrone, Sylvie. „Copper(I)-mediated anti-SN2' allylic substitution reactions with diorganozinc reagents“. Diss., [S.l.] : [s.n.], 2006. http://edoc.ub.uni-muenchen.de/archive/00006218.

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15

Cheng, Xiaohui. „Transition metal catalysed homogeneous hydroamination, allylic substitution and transfer hydrogenation reactions“. Thesis, King's College London (University of London), 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.410013.

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16

Baxendale, Ian Richard. „An investigative study into group 6 metal catalysed allylic substitution reactions“. Thesis, University of Leicester, 1999. http://hdl.handle.net/2381/33907.

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We have shown that a number of molybdenum(II) and tungsten(II) complexes are capable of catalysing the C-C bond forming allylic substitution reaction with silyl enol ethers derived from dicarbonyls or simple ketones, aldehydes, and esters as nucleophiles under mild conditions (rt, 1-2 h). Mechanistic and stereochemical experiments are indicative of a Lewis-acid catalysed process. The research was successful in identifying an number of key catalyst structures and properties for our continued investigation into M(II) catalysts. We have subsequently developed a catalytic system based on the chemistry of 2,2'-bipyridine and 1,10-phenanthroline substituted molybdenum(II) complexes {M(CO3 NN(SnCl3) Cl}. These complexes have promoted allylic substitution reactions with cinammyl derived allylic substrates with high levels of regioselectivity, the effect of the ligand, choice of solvent and steric congestion of the nucleophile have been investigated. The above investigation has lead to the development of chiral catalysts for the asymmetric allylic substitution reaction with modest enantioselectivity. Finally, we have prepared and characterised (including X-ray crystal structures) a pair of chiral 2,2'-bipyridyl ligands of C2-symmetry with the aim of introducing complementary chiral environments around a bound metal. These chiral ligands are currently being screened in our laboratory for asymmetric molybdenum catalysed allylic substitution reactions.

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17

Le, Chi. „Efforts Toward Improved Allylic Substitution via Pd-Catalyzed C-H Activation“. The Ohio State University, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=osu1396436482.

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18

Spangenberg, Thomas. „Synthesis of biomolecules using directed allylic substitution, multicomponent reaction and hydroformulation“. Université Louis Pasteur (Strasbourg) (1971-2008), 2008. http://www.theses.fr/2008STR13250.

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L'économie d'atomes est un enjeu majeur dans le domaine de la synthèse organique. Dans cette optique, la préparation de cibles d'intérêts biologiques (amino-acides, alcaloïdes) par de nouvelles stratégies de synthèse attire en permanence l'attention des chimistes. [. . . ]
Atomökonomische Reaktionen gewinnen in der organische Synthese eine zunehmend an Bedeutung, nicht nur bei der Herstellung einfacher Moleküle sondern auch für strukturell aufwendige und biologisch hochwirksame Moleküle wie z. B. Alkaloide und nicht natürliche Aminosäuren. [. . . ]

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19

Hagelin, Helena. „Palladium-catalyzed aromatic coupling and allylic substitution : an experimental and theoretical study /“. Stockholm, 1999. http://www.lib.kth.se/abs99/hage0528.pdf.

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20

Jiang, Xingyu. „Iridium-Catalyzed Asymmetric Allylic Substitution Reactions with Unstabilized Enolates and Prochiral Enolates“. Thesis, University of California, Berkeley, 2019. http://pqdtopen.proquest.com/#viewpdf?dispub=13422366.

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The following dissertation discuss the development of iridium-catalyzed asymmetric allylic substitution reactions with unstabilized enolates and prochiral enolates. These reactions include the enantioselective allylic substitutions with silyl ketene acetals, diastereo- and enantioselective allylic substitutions with ?-alkoxy ketones, and stereodivergent allylic substitutions with aryl acetic acid esters, azaaryl acetamides and azaaryl acetates. Chapter 1 provides a brief overview of transition-metal-catalyzed asymmetric allylic substitutions with enolates. This overview focused on the mechanism of allylations of enolates catalyzed by palladium complexes and iridium complexes. Additionally, methodologies for asymmetric allylations of unstabilized enolates are discussed in detail. Furthermore, this overview highlights the challenges and the strategies for the control of diastereoselectivity for the allylic substitutions with prochiral enolates. Chapter 2 describes the development of iridium-catalyzed enantioselective allylic substitution reactions with silyl ketene acetals, the silicon enolates of esters, under relatively neutral conditions. The ester products contain a quaternary carbon atom at the nucleophile moiety and a chiral tertiary carbon atom at the electrophile moiety. Chapter 3 describes the study on diastereoselective and enantioselective allylic substitution reactions with acyclic ?-alkoxy ketones. A metallacyclic iridium complex catalyzes the allylation of unstabilized copper(I) enolates generated in situ from acyclic ?-alkoxy ketones to form products with contiguous stereogenic centers. Chapter 4 describes the development of stereodivergent allylic substitutions with aryl acetic acid esters catalyzed synergistically by a metallacyclic iridium complex and a Lewis base co-catalyst. Through permutations of the enantiomers of the two chiral catalysts, all four stereoisomers of the products bearing two adjacent stereocenters are accessible with high diastereoselectivity and enantioselectivity. A stereochemical model is provided to understand the origin of high stereoselec-tivity. Chapter 5 describes a combination of catalysts that enable stereodivergent allylic substitution reactions with azaaryl acetamides and acetates. This combination of catalysts comprises a chiral metallacyclic iridium complex and a chiral bisphosphine-ligated copper(I) complex, which individually control the configuration of the electrophilic and nucleophilic carbon atoms, respectively. Chapter 6 extends from the work discussed in Chapter 5 and demonstrates iridium and copper complexes synergistically catalyze stereodivergent allylations to construct vicinal fully substituted and tertiary stereogenic centers in acyclic structures. In particular, fluorine-containing fully substituted stereocenters are readily constructed from fluorinated acetates.

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21

Norinder, Jakob. „Asymmetric Synthesis and Mechanistic Studies on Copper(I)-Catalyzed Substitution of Allylic Substrates“. Doctoral thesis, Stockholm : Department of Organic Chemistry, Stockholm University, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-1031.

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22

Stranne, Robert. „Investigation of Symmetry and Electronic Effects in Asymmetric Palladium-Catalysed Allylic Substitutions“. Doctoral thesis, KTH, Chemistry, 2001. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3283.

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23

O'Connor, Ryan. „Rhodium-catalysed allylic substitution with unstabilised carbon nucleophiles : asymmetric construction of carbon-carbon bonds“. Thesis, University of Liverpool, 2013. http://livrepository.liverpool.ac.uk/17253/.

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The controlled formation of carbon-carbon bonds is the bedrock of organic chemistry, with the asymmetric construction of stereogenic carbon-carbon bonds remaining a key motivation for the development of novel synthetic methodologies. Transition metal catalysis provides an important strategy in the arsenal of the modern synthetic chemist. While there is a plethora of transition metal-catalysed cross-couplings for the formation of sp2-sp2 and achiral sp2-sp3 carbon bonds, there are relatively few methodologies for the selective formation of stereogenic sp-sp3, sp2-sp3 and sp3-sp3 carbon-carbon bonds, the number of which that involve highly reactive organometallic reagents are fewer still. Two methodologies that can enable this asymmetric coupling are copper-catalysed SN2’ allylic alkylation and transition metal-catalysed allylic substitution. The overall utility of both these methods is described in the introductory review, which seeks to compare and contrast the relative advantages and disadvantage of both approaches. The asymmetric formation of carbon-carbon bonds utilising unstabilised carbon nucleophiles is generally dominated by the copper-catalysed SN2’ allylic alkylation. However, the copper-catalysed reaction suffers from poor substrate scope, in which electronically biased or symmetrical substrates are required in order to ensure favourable regioselectivities. Another restriction is that, for the formation of a stereocenter, the reaction is mechanistically limited to disubstituted allylic substrates. These linear substrates often require a multistep synthesis which involves a selective olefination, as an isomeric mixture of alkenes would result in the erosion of asymmetric induction. In contrast, there has been very little development of the analogous transition metal-catalysed allylic substitution utilising unstabilised carbon nucleophiles, especially in comparison to the analogous methodologies utilising stabilised carbon and heteroatom nucleophiles. Despite the numerous potential advantages that are afforded by this approach, a general method for the regio- and stereoselective transition-metal catalysed allylic substitution utilising unstabilised carbon nucleophiles has yet to be reported. Chapter 2 describes the development of a novel regio- and stereoselective rhodium-catalysed allylic substitution reaction, which utilises benzyl magnesium bromide as an unstabilised carbon nucleophile. Following a brief introduction to the rhodium-catalysed allylic substitution reaction, this chapter is organised into four distinct sections. The first of these outlines the identification of a suitable nucleophile, and the subsequent development of reaction conditions for the regioselective alkylation of secondary allylic carbonates with a range of benzyl magnesium bromides transmetallated with zinc iodide. Then the next section will deal with studies toward the development of the stereospecific variant, these studies will highlight the main challenges of deploying a sp3-hybridised carbon nucleophile. This section will also determine the absolute stereochemical outcome of the reaction, thus confirming the inner sphere mechanism of the reaction. The third section will demonstrate that how the limitation of the stereospecific reaction, namely the fluxionality of the rhodium-enyl, can be utilised to develop a regio- and diastereoselective alkylation for the formation of 1,2-stereoarrays containing tertiary and quaternary carbon stereocenters. Finally, preliminary studies towards the expansion of this methodology to include an sp2-hybridised vinylic nucleophiles for the preparation of 1,4-skipped dienes will be detailed. Overall, we have developed a novel, highly regioselective rhodium-catalysed allylic substitution of secondary allylic carbonates utilising highly unstabilised carbon nucleophiles. We also have developed a highly diastereoselective allylic substitution for the construction of both tertiary and quaternary carbon stereocenters, which to best of our knowledge, has yet to be described in the context of rhodium-catalysed allylic substitution utilising an unstabilised carbon nucleophile. We have successfully carried out preliminary studies towards the development of a rhodium-catalysed allylic substitution utilising a vinyl organometallic reagent as nucleophile, as well.

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24

Zhou, Yuebiao. „New Strategies for the Development of Catalytic Regio- and Enantioselective Allylic Substitution and Conjugate Addition Reactions:“. Thesis, Boston College, 2020. http://hdl.handle.net/2345/bc-ir:108959.

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Thesis advisor: Amir H. Hoveyda
Chapter 1. Catalytic SN2”-Selective and Enantioselective Substitution Reactions. The first broadly applicable strategy for SN2”-selective and enantioselective catalytic allylic substitution will be presented. It will be shown that transformations can be promoted by 5.0 mol% of a sulfonate-containing NHC–Cu complex (NHC = N-heterocyclic carbene), and may be carried out by the use of a commercially available allenyl–B(pin) (pin = pinacolato) or a readily accessible silyl protected propargyl–B(pin). Products bearing a 1,3 diene, a silyl allenyl or a propargyl moiety were obtained in high efficiency and selectivities. Also provided is insight regarding several of the unique mechanistic attributes of the catalytic process, obtained on the basis of kinetic isotope effect measurements and DFT studies. These investigations indicated that cationic π-allyl–Cu complexes are the likely intermediates, clarifying the role of the s-cis and s-trans conformers of the intermediate organocopper species and their impact on E:Z selectivity and enantioselectivity. It will also be shown we were able to highlight the utility of the approach by chemoselective functionalization of various product types, through which the propargyl, allenyl, or 1,3-dienyl sites within the products can be converted catalytically and chemoselectively to several synthetically useful derivatives. Chapter 2. NHC–Copper–Hydride-Catalyzed Enantioselective Processes with Allenyl Boronates and its Application in Natural Product Synthesis. Here, the development of a catalytic process that delivers otherwise difficult-to-access organoboron compound will be detailed. These processes involve the combination of a hydride, an allenyl–B(pin) and an allylic phosphate. As will be discussed, two unique selectivity problems were solved: avoiding rapid Cu–H reduction of an allylic phosphate, while promoting its addition to an allenylboronate as opposed to the commonly observed Cu–B exchange. We were able to underscore the considerable utility of the approach by applications to preparation of the linear fragment of pumiliotoxin B (myotonic, cardiotonic) and the first enantioselective synthesis of netamine C (anti-tumor), which also served to confirm its stereochemical identity. Chapter 3. Catalytic Enantioselective Prenyl Conjugate Addition Reactions. In this final section, studies leading to the development of the first class of catalytic enantioselective strategies for prenyl conjugate additions will be detailed. At the core of these investigations was finding ways to overcome two problems. One challenge originated from the fact that highly activated allylmetal species often deliver product with low enantioselectivity. The other was that regioselectivity was difficult to control owing to a strong preference for γ-selective additions. As will be described, we were able to address these difficulties by the use of a hydroxy NHC-copper complex and 3,3-dimethyl allyl–B(pin) as a reagent. In the end, we were able to use acyclic as well as cyclic enoates as substrates. The results of DFT studies that provide insight regarding varying selectivity profiles with different chiral ligands will be discussed as well
Thesis (PhD) — Boston College, 2020
Submitted to: Boston College. Graduate School of Arts and Sciences
Discipline: Chemistry

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25

Müller, Constanze Annelie. „Mass spectrometric screening of chiral catalysts by monitoring the back reaction: Palladium-catalysed allylic substitution“. Göttingen Cuvillier, 2008. http://d-nb.info/989139719/04.

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26

Müller, Constanze A. „Mass spectrometric screening of chiral catalysts by monitoring the back reaction : palladium-catalysed allylic substitution /“. [S.l.] : [s.n.], 2008. http://edoc.unibas.ch/diss/DissB_8322.

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27

Olsson, Vilhelm. „Development of New Synthetic Routes to Organoboronates by Catalytic Allylic Substitution and C-H bond Functionalization“. Doctoral thesis, Stockholms universitet, Institutionen för organisk kemi, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-27753.

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This thesis describes the development of new catalytic methods for the synthesis and application of organometallic reagents, mainly focusing on allylboronic acid derivatives. Thus, palladium pincer-complex catalysis has been applied for extending the scope of palladiumcatalyzed borylation reactions in the synthesis of regio- and stereodefined functionalized allylboronic acid derivatives. These novel allylboronic acids were also employed as substrates in palladium catalyzed regioselective coupling reactions with iodobenzenes. We have also developed a new one-pot sequence based on preparation of allyl- and vinylboronates via catalytic carbon-hydrogen bond activation/borylation reactions. The synthetic scope of the reaction as well as mechanistic studies on the borylation process are presented. Finally, the synthesis of new chiral palladium pincer-complexes is described. These species were employed as catalysts in asymmetric electrophilic allyation of imines.

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28

Selim, Khalid Bashir Shaaban. „Development of chiral ligand-copper(1)-catalyzed asymmetric conjugate addition and allylic substitution with organometallic reagents“. 京都大学 (Kyoto University), 2009. http://hdl.handle.net/2433/126604.

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29

McGrath, Kevin Patrick. „Enantioselective Methods for Allylic Substitution and Conjugate Addition Reactions Catalyzed by N-Heterocyclic Carbene-Copper Complexes“. Thesis, Boston College, 2016. http://hdl.handle.net/2345/bc-ir:106792.

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Thesis advisor: Amir H. Hoveyda
Chapter 1 Catalytic Enantioselective Addition of Organoaluminum Reagents Catalytic methods involving the enantioselective addition of both commercially available as well as in situ generated organoaluminum reagents are reviewed. An overview of additions to aldehydes, ketones, and imines is provided as well as the difficulties and limitations of such transformations. Furthermore, additions to unsaturation adjacent to a leaving group to form a new stereogenic center are examined. Finally, conjugate addition reactions wherein an organoaluminum reagent is added to an olefin adjacent to a carbonyl or nitro group are discussed. Chapter 2 Synthesis of Quaternary Carbon Stereogenic Centers through Enantioselective Cu-Catalyzed Allylic Substitution with Alkenylaluminum Reagents A method for the formation of 1,4-diene containing quaternary stereogenic centers through catalytic enantioselective allylic substitution is disclosed. The addition of alkyl- and aryl-substituted alkenylaluminum reagents to trisubstituted allylic phosphates is promoted by 0.5–2.5 mol % of a sulfonate-containing bidentate N-heterocyclic carbene–copper complex. Products containing a quaternary stereogenic center as well as a newly formed terminal olefin are obtained in up to 97% yield and 99:1 er with high site selectivity (>98:2 SN2’:SN2). The requisite nucleophiles are generated in situ through hydroalumination of terminal alkynes. The utility of the method is demonstrated through a concise synthesis of natural product bakuchiol. Chapter 3 A Multicomponent Ni-, Zr-, Cu-Catalyzed Strategy for Enantioselective Synthesis of Alkenyl-Substituted Quaternary Carbons Despite the widespread use of conjugate addition in organic synthesis, few reports pertain to the addition of nucleophiles to acyclic systems and none in which the nucleophile is an alkene. Herein, we report the first examples of enantioselective conjugate addition of alkenylmetal reagents to trisubstituted enones to form all-carbon quaternary stereogenic centers. Alkenylaluminum nucleophiles are prepared through a site-selective Ni-catalyzed hydroalumination of terminal alkynes and the requisite E-trisubsituted enones are the products of a regioselective Zr-catalyzed carboalumination/acylation of a terminal alkyne. Products are obtained in up to 97% yield and 99:1 er. A model for enantioselectivity, supported by DFT calculations, is proposed. Chapter 4 Formation of Tertiary Centers through Catalytic Enantioselective Conjugate Addition of Alkenylaluminum Reagents to Acyclic Enones We have developed an enantioselective NHC–Cu catalyzed synthesis of tertiary centers in acyclic systems using in situ generated alkenylaluminum reagents, as current methods typically rely on Rh-catalysis at high temperatures with alkenyl boronic acids in protic solvents. Moreover, most examples include chalcone-derived substrates, which, while more reactive, often preclude further functionalization. With the current method, we are able to couple a variety of alkenyl nucleophiles with α,β-unsaturated ketones. E- or Z-silylalkenylaluminum reagents, derived from hydroalumination of silyl-protected alkynes, lead to products in good yields and high enantioselectivities. Additionally, both the α- and β-alkenylaluminum reagents participate in the reaction. Chapter 5 Development of N-Heterocyclic Carbene–Cu Catalyzed Allylic Substitution of Diboryl Methane to Morita-Baylis-Hillman Derived Allylic Phosphates We have developed a method for the coupling of a geminyl diboron reagent with Morita-Baylis-Hillman derived trisubstituted ester-containing allylic phosphates. With 10 mol % of an in situ generated NHC–Cu complex and 1.5 equivalents of the boron reagent, we are able to form the desired product in high regio- and enantioselectivity with a 2,5-ditert-butyl containing carbene. Simple aryl substituents as well as those containing a halogen or an electron-withdrawing group furnish the desired products in up to 85% yield and 98:2 er. Alkyl-containing substrates are also competent reaction partners, although longer chain aliphatics results in slightly diminished enantioselectivity. We are pursuing the application of this method to the synthesis of α-methylene lactones which can be further functionalized to natural products like tubulin polymerization inhibitor (–)-steganone and glaucoma medication (+)-pilocarpine
Thesis (PhD) — Boston College, 2016
Submitted to: Boston College. Graduate School of Arts and Sciences
Discipline: Chemistry

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30

Gao, Fang. „Copper-Catalyzed Enantioselective Allylic Substitution Reactions with Organoaluminum and Boron Based Reagents Promoted by Chiral Sulfonate Bearing N-Heterocyclic Carbenes“. Thesis, Boston College, 2013. http://hdl.handle.net/2345/bc-ir:101227.

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Thesis advisor: Amir H. Hoveyda
Chapter 1. A Review of Catalytic Enantioselective Allylic Substitution (EAS) with Chiral Sulfonate Containing N-heterocyclic Carbenes (NHC). A comprehensive review of enantioselective allylic substitution reactions, which are promoted by a chiral N-heterocyclic carbene metal complex that features a unique sulfonate motif, is provided in this chapter. Reactions are classified into two categories. One class of transformations is catalyzed by a series of easily modifiable sulfonate bearing NHC-Cu complexes, with which a range of nucleophilic organometallic reagents (i.e., organozinc-, aluminum-, magnesium- and boron-based) that carry different carbon-based units are readily utilized in efficient and highly selective C-C bond forming processes. Another set of reactions exclude the use of a copper salt; catalytic amount of a sulfonate containing imidazolinium salt is capable of promoting additions of alkyl Grignard, zinc and aluminum species to easily available allylic electrophiles in a site- and enantioselective fashion. The mechanistic scenarios of both catalytic systems that account for the observed experimental data are discussed in detail. Chapter 2. Cu-Catalyzed Enantioselective Allylic Substitutions with Aryl- and Heteroarylaluminum Reagents. In this chapter, the first examples of EAS reactions of aryl- and heteroaryl-substituted dialkylaluminum reagents to a wide range of trisubstituted allylic phosphates are demonstrated through a facile and selective catalysis rendered possible by an in situ generated sulfonate containing NHC-Cu complex, delivering enantiomerically enriched olefin products that bear an all carbon quaternary stereogenic center. The requisite organometallic species are easily prepared from either the corresponding aryl- and heteroaryl halides, or through efficient and site selective deprotonation at the C-2 position of furan and thiophene; such aluminum entities are readily used in situ without the requirement of purification. Application to small molecule natural product synthesis is also carried out to illustrate the utility of the present protocol. Chapter 3. Cu-Catalyzed Enantioselective Allylic Substitutions with Alkenylaluminum Reagents. This chapter focuses on our research towards construction of enantioenriched tertiary and quaternary stereogenic centers that are substituted with two further functionalizable alkenes. The first combination of the study involves the addition of stereochemically well-defined trisubstituted alkenylaluminum reagents to disubstituted allylic phosphates; the transformation commences with a silyl-directed stereoselective hydroalumination and finishes with an enantioselective Cu-catalyzed EAS promoted by a sulfonate bearing NHC. Such reactions deliver molecules that feature silicon containing trisubstituted olefin adjacent to the tertiary stereogenic center; subsequent conversion of the versatile silicon group to a proton reveals the first set of examples that incorporate pure Z alkene in Cu-catalyzed EAS. The stereoselective and concise synthesis of naturally occurring small molecule nyasol demonstrates the utility of the above method. On a different front, Ni-catalyzed site-selective hydroalumination of terminal alkynes has opened new possibility of introducing 1,1-disubstituted olefins in Cu-catalyzed EAS in the formation of tertiary stereogenic center containing enantioenriched organic building blocks. Such catalytic hydrometallation procedure also allows efficient access to alkenylaluminums that are derived from the conventionally problematic aromatic alkynes. The importance of efficient and selective synthesis of terminal aryl-substituted alkenylaluminum species is showcased in NHC-Cu-catalyzed EAS reactions that construct all-carbon quaternary stereogenic centers; a three-step convergent synthesis of natural product bakuchiol in enantiomerically enriched form highlights the potential of the current protocol in chemical synthesis. Chapter 4 Cu-Catalyzed Enantioselective Allylic Substitutions with Alkenylboronic Acid Pinacol Ester Reagents and Applications in Natural Product Synthesis. Within this chapter, we disclose the efficient utilization of alkenylboron reagents in Cu-catalyzed EAS reactions, which lead to highly site and enantioselective formations of molecules that contain both tertiary and quaternary carbon stereogenic centers. Unlike their aluminum-based counterparts, the use of boron-based reagents allows effective delivery of sensitive organic function groups, such as a carbonyl, which would be incompatible in the hydrometallation process with dibal-H. Our efforts accumulate to the first report of incorporation of all carbon quaternary centers that are substituted with unsaturated ester and aldehyde units in the EAS products; such a method facilitates the concise diastereo- and enantioselective synthesis of Pummerer's ketone and it's trans isomer. Further development of the above protocol towards the construction of tertiary stereogenic centers requires the design of new chiral sulfonate-containing imidazolinium salts as the ligand precursors and has lead to the employment of a broader range of alkenylboron species, which feature readily functionalizable motifs. Subsequent demonstrations in enantioselective synthesis of a variety of small molecule natural products showcase the utility
Thesis (PhD) — Boston College, 2013
Submitted to: Boston College. Graduate School of Arts and Sciences
Discipline: Chemistry

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31

Soorukram, Darunee. „Copper(I)-mediated regio- and stereoselective allylic substitutions and their applications to natural product syntheses“. Diss., [S.l.] : [s.n.], 2006. http://edoc.ub.uni-muenchen.de/archive/00006234.

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32

Bricout, Hervé. „Isomérisation et substitution nucléophile en série allylique catalysées par des complexes phosphorés du nickel“. Lille 1, 1997. https://pepite-depot.univ-lille.fr/LIBRE/Th_Num/1997/50376-1997-21.pdf.

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Le complexe ni(dppb)#2, forme en solution par combinaison du nickelbis(cycloocta-1,5-diene) avec le ligand 1,4-bis(diphenylphosphino)butane (dppb), présente des propriétés catalytiques intéressantes dans la chimie des dérives allyliques: associe à l'acide trifluoroacetique, ce complexe catalyse l'isomerisation du géraniol en citronellal ; les meilleurs rendements sont obtenus en présence de butane-1,2-diol. Utilise sans cocatalyseur acide, le même complexe est actif dans l'allylation de nucléophiles mous par des composes allyliques oxygènes, azotes, ou dérives du 2-allylmalonate de diméthyle. Cette alternative possible à la catalyse traditionnelle par le palladium (réaction de tsuji-trost) est exploitée dans la réaction d'alkylation asymétrique de l'acetate de cyclohex-2-enyle par le malonate de dimethyle ; des excès enantiomeriques allant jusque 40% sont obtenus en utilisant des ligands chiraux dérives d'aminoalcools. Pour certaines réactions de substitution nucléophile allylique effectuées, la polarité du solvant ainsi que la présence d'un sel dans le milieu réactionnel a une grande influence sur la vitesse observée. D'autre part, il apparait que si les complexes du palladium présentent une activité catalytique vraisemblablement supérieure à celle des complexes du nickel dans le cas des acetates allyliques, une tendance inverse est observée avec les dérives allyliques possédant un groupement partant médiocre

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33

Oliver, Samuel. „Rhodium-catalysed allylic substitution with an acyl anion equivalent : asymmetric construction of acyclic quaternary carbon stereogenic centres“. Thesis, University of Liverpool, 2012. http://livrepository.liverpool.ac.uk/8433/.

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The asymmetric construction of substituted carbonyl compounds, particularly those containing α-quaternary carbon stereogenic centres, remains a significant area of interest in organic chemistry. This can largely be attributed to the ubiquity and versatility of these compounds as synthetic intermediates, and the presence of such motifs in a range of biologically active pharmaceutical agents and natural products. In this context, the transition metal-catalysed allylic substitution provides an extremely powerful tool for the asymmetric construction of a range of C-C, C-N and C-O bonds, and has found significant application in the synthesis of substituted carbonyl compounds. The overall utility of these methods is described in the introductory review, which seeks to compare and contrast two alternative bond forming strategies for the asymmetric construction of these units via allylic substitution. While this work is generally dominated by the asymmetric allylic alkylation of unstabilised enolates, these reactions are often limited by the numerous challenges associated with the regio- and stereoselective formation of an enolate nucleophile, product racemisation and polyalkylation, and their relatively narrow substrate scope. In contrast, the transition metal-catalysed allylic substitution with an acyl anion equivalent has the potential to provide a range of α-substituted carbonyl compounds via a fundamentally different bond forming event, in which the acyl functionality is installed directly into the allylic framework. Despite the numerous potential advantages that are afforded by this approach, a general method for the regio- and stereoselective transition-metal catalysed allylic acylation of substituted electrophiles has yet to be reported. Chapter 2 describes the development of a novel regio- and stereospecific rhodium-catalysed allylic substitution reaction, which utilises a trialkylsilyl-protected cyanohydrin as a convenient acyl anion equivalent. Following a brief introduction to the rhodium-catalysed allylic substitution reaction, this chapter is organised into three distinct sections. The first of these outlines the identification of a suitable nucleophile, and the subsequent development of reaction conditions for the regioselective alkylation of tertiary allylic carbonates with a range of stabilised aryl cyanohydrins. The stereospecific variant of this transformation, which involves the direct conversion of an enantiomerically enriched acyclic tertiary allylic alcohol to the corresponding α-quaternary substituted aryl ketone, is then described. Finally, the expansion of this methodology to the preparation of more synthetically useful α,β-unsaturated ketones, and preliminary investigations towards the application of secondary allylic carbonates, are outlined. Overall, this method provides a fundamentally novel bond construction towards the synthesis of α-quaternary substituted carbonyl compounds, and circumvents many of the problems associated with conventional enolate alkylation reactions. Thus, we anticipate that the methodology outlined herein will find significant application in target directed synthesis, particularly in the preparation of complex bioactive pharmaceuticals and natural products that contain quaternary carbon stereogenic centres.

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Larsson, Johanna M. „Transition metal-catalyzed allylic and vinylic functionalization : Method development and mechanistic investigations“. Doctoral thesis, Stockholms universitet, Institutionen för organisk kemi, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-89524.

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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.

At the time of the doctoral defense, the following paper was unpublished and had a status as follows: Paper 4: Manuscript.

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Arnold, Jeffrey Scott. „Rhodium-catalyzed asymmetric amination of trichloroacetimidates with application to nitrogen heterocycle synthesis“. Diss., University of Iowa, 2014. https://ir.uiowa.edu/etd/4565.

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Chiral quaternary centers possessing a bond to nitrogen are an important class of amine compounds, however, methods for their enantioselective preparation remain sparse. The focus of my graduate research described herein has been the development of a novel rhodium-catalyzed regio- and enantioselective allylic aryl amination of tertiary trichloroacetimidates for the synthesis of amine-bearing quaternary centers (also termed α,α-disubstituted amines). Prior to our work, allylic carbonates and acetates had been successfully utilized in transition-metal catalyzed substitution reactions with anilines for the asymmetric synthesis of tertiary centers. In contrast, these electrophiles have not proven useful in dynamic kinetic asymmetric transformations (DYKAT) that yield enantioenriched amine products, and no reports describing the asymmetric preparation of α,α-disubstituted allylic aryl amines via allylic substitution are noted. Many of the ideas for development of our rhodium-catalyzed amination method were based upon the findings of Overman where linear allylic trichloroacetimidates are utilized in [3,3]-sigmatropic rearrangements and substitution reactions by oxygen nucleophiles under palladium (II) catalysis. Our method diverges from this previous work by application of branched allylic trichloroacetimidates where the olefin component is mono-substituted, and the use of a transition-metal complex capable of facile oxidative addition to an intermediate organometallic complex. We hypothesized that bidentate chelation of these substrates at the imidate nitrogen and the relatively unimpeded olefin by a rhodium (I) complex would lead to rapid ionization to an activated complex and competent electrophile for substitution by neutral aniline nucleophiles. This premise was supported by many control studies and resulted in the development of a highly regioselective amination of branched allylic trichloroacetimidates for the operationally simple synthesis of α-substituted and α,α-disubstituted allylic aryl amines. Work followed utilizing chiral diene ligands that rendered the reaction enantioselective for preparation of enantioenriched tertiary and quaternary amine-containing centers. A highlight of these studies is the first example of DYKAT using a tertiary electrophile and an aryl amine nucleophile. The reaction is of broad substrate scope, is tolerant of varied functionality and substitution patterns on the nucleophilic partner, and solves regioselectivity issues often encountered with some substrate and aniline classes. I end by showing the synthetic utility of our rhodium-catalyzed reaction by applying this method to the synthesis of enantioenriched amino acids and construction of 7-membered nitrogen-containing heterocycles by a 2-step DYKAT amination and olefin hydroacylation sequence.

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Guillarme, Stéphane. „Synthèse de nouveaux nucléosides acycliques : étude de la réaction de substitution allylique sur des dérivés cyclobuténiques : approche vers la synthèse de nucléosides cyclobuténiques“. Le Mans, 2002. http://cyberdoc.univ-lemans.fr/theses/2002/2002LEMA1009.pdf.

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Lors de notre travail, nous nous sommes intéressés à la synthèse de nouveaux nucléosides acycliques et carbocycliques à propriétés antivirales et anticancéreuses potentielles. Dans la première partie de notre étude, les nucléosides acycliques, analogues du penciclovir, ont été préparés par introduction des bases azotées par une réaction de Michael. Cette stratégie, très peu utilisée, a permis également l'incorporation de bases déazas qui sont peu nucléophiles et souvent introduites par construction. La réaction des bases sur les accepteurs de Michael s'est effectuée avec une bonne régiosélectivité, confirmée par différentes expériences RMN, et notamment par des corrélations 1H/13C directes et à longue distance. Tous les nucléosides acycliques isolés ont été soumis aux tests antiviraux, anticancéreux et antiherpétiques. Deux d'entre eux ont présenté une activité antiherpétique. Dans la deuxième partie de notre travail, la synthèse d'analogues de nucléosides porteurs d'une fonction méthylène a été décrite. Les bases azotées ont été introduites par une réaction de substitution sur un composé comportant un groupe acétate. La réaction avec les purines s'est effectuée avec une mauvaise régiosélectivité donnant ainsi des résultats surprenants voire inédits. Enfin, dans une dernière partie, nous avons étudié la réaction de substitution allylique catalysée par le palladium sur des dérivés cyclobuténiques. Malgré les différentes difficultés rencontrées, nous avons mis en évidence le premier exemple de substitution nucléophile sur un complexe p-allylique cyclobuténique. Dans un premier temps, les substrats cyclobuténiques ont été synthétisés. Nous les avons ensuite opposé à des nucléophiles classiques. Suivant les cas, nous avons isolé soit le composé cyclobuténique soit son isomère diénique soit un mélange des deux composés. La configuration des diènes a été déterminée par des expériences RMN. La régiosélectivité de la réaction a été également abordée. Cette réaction, une fois bien maîtrisée, devrait permettre de synthétiser des nucléosides cyclobuténiques, analogues de l'abacavir, molécule possédant une activité anti-VIH comparable à l'AZT
This work deals with the synthesis of acyclic and carbocyclic nucleosides as potential antiviral and antitumoral compounds. In the first part of our study, acyclic nucleosides, analogues of penciclovir, have been prepared by conjugate addition of nucleobases on different Michael acceptors. With this unusual way of synthesis of acyclic nucleosides, deaza nucleobases which are low nucleophile have been incorporated. Addition of nucleobases on Michael acceptors have generally proceeded with good regioselectivity. The regioselectivity has been elucidated by NMR studies, using the 2D experiment HMBC. Nucleosides have been tested for their antiviral and antitumoral properties. Two of them have an anti-herpes activity. In the second part, the synthesis of acyclic nucleosides containing a methylene group have been described. Nucleobases have been introduced by a substitution reaction on a compound containing a leaving group. Some problems of regioselectivity have been noticed with purines. In the last part of our work, we have studied the allylic substitution reaction catalysed by palladium on cyclobutene derivatives. We have showed the first example of nucleophile substitution on π-allylic cyclobutene-based complexes. The cyclobutene derivatives were synthesised and were then opposed to different nucleophiles. With few nucleophiles, cyclobutene compounds were not isolated but only its isomers obtained by thermal ring-opening of the cyclobutene. Configuration of dienes was proved by NOE experiments. The regioselectivity of the reaction has been also approached. Cyclobutene-based nucleosides could be prepared by this reaction using nucleobases as nucleophiles

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Shi, Ying. „Copper-catalyzed Enantioselective Allylic Substitutions and Conjugate Additions Promoted by Chiral Sulfonate- or Alkoxy-containing N-heterocyclic Carbenes“. Thesis, Boston College, 2017. http://hdl.handle.net/2345/bc-ir:107648.

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Thesis advisor: Amir H. Hoveyda
Chapter 1. A Review of Sulfonate-Containing NHC Ligands in Copper-Catalyzed Enantioselective Transformations—Maneuvering Selectivities in Tight Space. A comprehensive review of enantioselective copper-catalyzed transformations, which are promoted by a chiral N-heterocyclic carbene metal complex that features a unique sulfonate motif, is provided in this chapter. Reactions have been categorized into four sets: allylic substitutions conjugate additions, Cu-B additions alkenes and multicomponent reactions. The mechanistic scenarios provided by DFT calculations accounts for their uniquely reaction profile in enantioselective allylic substitutions (EAS), enantioselective conjugate additions (EAS) and enantioselective Cu-B additions to alkenes. Mechanistic investigations (density functional theory calculations and deuterium labeling) point to a bridging function for an alkali metal cation connecting the sulfonate anion and a substrate’ s phosphate group to form the branched addition products as the dominant isomers via Cu(III) π -allyl intermediate complexes in EAS reactions. Sulfonate-bearing NHC ligand with different substitution patterns promote EAS reactions with different reactivity and enantioselectivity. We also developed a guideline to follow to choose the proper sulfonate-based NHC ligands according to the combination of the substrates and the nucleophiles. Chapter 2. NHC–Cu-Catalyzed Enantioselective Allylic Substitutions with Silyl-protected Propargyl Boron Reagent to Generate Tertiary and Quaternary Carbon Stereogenic Centers. Catalytic allylic substitution reactions involving a propargylic nucleophilic component are presented; reactions are facilitated by 5.0 mol % of a catalyst derived from a chiral N-heterocyclic carbene (NHC) and a copper chloride salt. A silyl-containing propargylic organoboron compound, easily prepared in multi-gram quantities, serves as the reagent. Aryl- and heteroaryl-substituted disubstituted alkenes within allylic phosphates and those with an alkyl or a silyl group can be used. Functional groups typically sensitive to hard nucleophilic reagents are tolerated, particularly in the additions to disubstituted alkenes. Reactions may be performed on the corresponding trisubstituted alkenes, affording quaternary carbon stereogenic centers. Incorporation of the propargylic group is generally favored (vs allenyl addition; 89:11 to >98:2 selectivity); 1,5-enynes can be isolated in 75−90% yield, 87:13 to >98:2 SN2′:SN2 (branched/linear) selectivity and 83:17−99:1 enantiomeric ratio. Utility is showcased by conversion of the alkynyl group to other useful functional units. Application to stereoselective synthesis of the acyclic portion of antifungal agent plakinic acid A, containing two remotely positioned stereogenic centers, by sequential use of two different NHC–Cu-catalyzed enantioselective allylic substitution (EAS) reactions further highlights utility. Chapter 3. NHC–Cu-Catalyzed Enantioselective Allylic Substitutions with Methylenediboron to Generate Tertiary and Quaternary Carbon Stereogenic Centers. A catalytic EAS method for the site- and enantioselective addition of commercially available di-B(pin)-methane to disubstituted allylic phosphates is introduced. Transformations are facilitated by a sulfonate-containing NHC–Cu complex and products are obtained in 63–95% yield, 88:12 to >98:2 SN2’/SN2 selectivity, and 85:15–99:1 enantiomeric ratio. The utility of the approach is highlighted by its application to the formal synthesis of the cytotoxic natural product rhopaloic acid A, in an all-catalytic-method synthesis route. Catalytic EAS methods of the di-B(pin) methane to Z-trisubstituted allylic phosphates are also disclosed and DFT calculations provide insights to the stereochemical models for those transformations and rationales for the choice of Z-trisubstituted allylic phosphates as the starting materials. Chapter 4. Enantioselective NHC–Cu-Catalyzed Prenyl Conjugate Additions to Enoates to Generate Tertiary Carbon Stereogenic Centers. An efficient catalytic protocol for generation of prenyl-bearing tertiary carbon stereogenic centers from aryl-substituted enoates was achieved in the presence of a chiral alkoxy-based NHC–Cu complex. A range of aryl and heteroaryl-substituted substrate were suitable substrates, the corresponding prenyl conjugate addition products were generated in up to 94% yield and 95:5 enantioselectivity. The utility of the current method has been shown in the application to the synthesis of a selective integrin antagonist. DFT calculations provided a stereochemical model for the ECA reaction employing alkoxy-containing NHC–Cu catalyst
Thesis (PhD) — Boston College, 2017
Submitted to: Boston College. Graduate School of Arts and Sciences
Discipline: Chemistry

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Defieber, Christian Volker. „Chiral olefins as novel ligands in asymmetric synthesis and the development of water and ammonia equivalents in iridium-catalyzed allylic substitution /“. Zürich : ETH, 2007. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=17170.

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39

Mandai, Kyoko. „Cu-Catalyzed Enantioselective Allylic Substitutions with Organomagnesium and Organoaluminum Reagents Promoted by N-Heterocyclic Carbenes for the Formation of Quaternary Stereogenic Centers“. Thesis, Boston College, 2010. http://hdl.handle.net/2345/1329.

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Thesis advisor: Amir H. Hoveyda
Chapter One: An overview of Cu-catalyzed enantioselective allylic substitutions with organometallic reagents. Chapter Two: Development of Cu-catalyzed enantioselective allylic alkylations of allylic chlorides with Grignard reagents for the formation of all-carbon quaternary stereogenic centers is disclosed. Chapter Three: Development of Cu-catalyzed enantioselective allylic substitutions of allylic phosphates with alkyl, aryl, and heterocyclic aluminum reagents for the formation of quaternary stereogenic centers is discussed
Thesis (MS) — Boston College, 2010
Submitted to: Boston College. Graduate School of Arts and Sciences
Discipline: Chemistry

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Thomasset, Amélia. „Synthèse de carbènes N-hétérocycliques chiraux et applications en catalyse asymétrique“. Phd thesis, Université Paris Sud - Paris XI, 2013. http://tel.archives-ouvertes.fr/tel-01070636.

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Ce travail de thèse porte dans un premier temps sur la synthèse de nouveaux sels d'azolinium chiraux précurseurs de carbènes N-hétérocycliques. Deux nouvelles familles de sels ont été préparées à partir de la L-proline. Nous avons pu caractériser les NHC issus de ces sels, par la formation des dimères, des thiones et des complexes de rhodium correspondants. Dans un second temps, ces nouveaux sels d'azolinium ont été évalués dans la réaction d'addition conjuguée de réactifs de Grignard sur des cétones α,β insaturées. Les résultats ont montré de très bonnes activités catalytiques, et de très bonnes régiosélectivités. Les énantiosélectivités obtenues sont encourageantes. Ensuite, ces catalyseurs ont été engagés dans la réaction de substitution allylique. Une bonne activité catalytique a aussi été observée malgré des régiosélectivités et des énantiosélectivités modérées. Enfin, ces sels ont été employés comme précurseurs de NHC pour la réduction asymétrique de cétones aromatiques par transfert d'hydrogène. Les complexes formés se sont montrés actifs mais non énantiosélectifs.

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Balanta, Castillo Angelica. „Novel molecular and colloidal catalysts for c-c bond formation processes“. Doctoral thesis, Universitat Rovira i Virgili, 2011. http://hdl.handle.net/10803/66243.

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Esta tesis doctoral se centró en la síntesis y la caracterización de nanopartículas metálicas (Pd, Ni, Pt) estabilizadas por varios tipos de ligandos y el uso de estas nanopartículas en reacciones de formación de nuevos C-C o C-heteroatomo: a) Reacción de substitución alílica catalizadas por Pd; b) Reacción de acoplamiento asimétrico de Suzuki-Miyaura; c) Reacción de acoplamiento de Suzuki-Miyaura; d) reacción de adición 1,4 de ácidos borónicos a cetonas. En cada una de estas reacciones se llevó a cabo la síntesis y caracterización de nanoparticulas metálica y complejos moleculares usando muchos tipos de ligandos en los sistemas moleculares y los sistemas análogos cataliazados por nanopartículas. Excelentes actividades y enatioselectividades fueron obtenidas en la reacción de alquilación y aminación alílica. Además, estos sistemas fueron reciclados usando líquidos iónicos. También, nuevos y selectivas nanoparticulas fueron sintetizadas y caracterizadas. Estas nanopartículas fueron usadas exitosamente en varias reacciones de formación de nuevos enlaces C-C.
This doctoral thesis focuses on the synthesis and characterization of metal nanoparticles (Pd, Ni, Pt) stabilized by several types of ligands and the used of these nanoparticles in new C-C or C-heteroatom bond formation reactions: a) Pd-catalysed asymmetric allylic substitution reactions; b) Pd-catalysed asymmetric Suzuki-Miyaura coupling reactions; c) Ni-catalysed Suzuki-Miyaura coupling reactions; d) Pt-catalysed 1,4-addition of phenylboronic acid to 2-cyclohexen-1-one reaction. For each reaction, the synthesis and characterization of metal nanoparticles and molecular complexes using several types of ligands were performed and both types of catalytic systems were tested in the appropriate reactions. Remarkably, excellent enantioselectivities using Pd/phosphite ligand were obtained in allylic substitution reaction. An efficient recovery of the catalytic system was carried out using ionic liquids as reaction medium. New active and selective nanoparticles were synthesized and characterized. These nanoparticles were applied successfully in various C-C bond formation reactions.

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Eichelsheim, Tanja. „Oligonucleotide based ligands in homogeneous transition metal catalysis“. Thesis, University of St Andrews, 2012. http://hdl.handle.net/10023/3168.

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Catalysis plays an important part in our society. Numerous transition metal catalysts have been developed which can convert many different substrates in a wide range of reactions. Catalysis also plays an important role in nature and therefore special catalysts, enzymes, have evolved over time. Enzymes are tremendously efficient giving high yields and selectivities both regio and chemical but have a limited substrate and reaction scope. It was speculated that by combining the two, an ideal catalyst can be obtained. We planned to achieve this by introducing a transition metal, the catalytic centre, into the chiral environment of a double helical oligonucleotide. The transition metals were introduced by coordinating them to a ligand which was located in the chiral environment of a double helix. The ligand was either covalently bound (Chapter 2) or non-covalently bound (Chapter 3) to the oligonucleotide (Figure 1). Figure 1: A) covalent introduction of a transition metal into a nucleotide B) non-covalent introduction of a transition metal into a nucleotide For the covalent approach a phosphine ligand was chosen. A nucleoside was modified with an alkyne to which a phosphine moiety could be coupled via the copper catalysed 1,3-dipolar cycloaddition. The modified nucleoside was incorporated into an oligonucleotide before attempting to attach the phosphine moiety. The monomer was used as a ligand in allylic substitution and hydroformylation. In the non-covalent approach polyamide minor groove binders were functionalised with an amine linker. Phosphine moieties were connected via amide bond formation. Although the coupling worked effortlessly the phosphines oxidised during purification therefore dienes were also investigated.

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Posseme, Françoise. „Synthèse et évaluation biologique d'analogues borylés et fluorés de polyamines. Nouvelle voie d'accès stéréocontrôlée ayx (E)-(gamma-alocoxyallyl)boronates alpha-substutués“. Rennes 1, 2001. http://www.theses.fr/2001REN10149.

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La première partie traite de la mise au point de nouveaux vecteurs d'atomes de bore 10 ou de fluor 18, en vue d'une utilisation en boroneurothérapie (BNCT) ou en tomographie par émission de positons (TEP). Dans un premier temps, un rappel bibliographique concernant les deux techniques met en évidence les exigences requises dans l'élaboration de telles molécules. En considérant les nombreuses propirétés polyamines, elles apparaissent comme des candidats potentiels, capables de vectoriser un hétéroélément dans un tissu cancéreux. Dans cette optique, nous avons synthétisé une série d'analogues de spermidine et de putrescine borylés et fluorés. Les synthèses utilisées sont efficaces, sélectives et transposables à la chimie du 10B ou du 18F. L'évaluation biologique in vitro de ces composés a donné des résultats comparables à ceux obtenus avec les molcécules couramment utilisées en BNCT. Les dosages de bore in vivo, démontrent que les dérivés borylés présentent une bonne spécificité tumorale, mais s'accumulent à des concentrations insuffisantes

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Hallman, Kristina. „Asymmetric Catalysis : Ligand Design and Conformational Studies“. Doctoral thesis, KTH, Chemistry, 2001. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3275.

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This thesis deals with the design of ligands for efficientasymmetric catalysis and studies of the conformation of theligands in the catalytically active complexes. All ligandsdeveloped contain chiral oxazoline heterocycles.

The conformations of hydroxy- and methoxy-substitutedpyridinooxazolines and bis(oxazolines) during Pd-catalysedallylic alkylations were investigated using crystallography,2D-NMR techniques and DFT calculations. A stabilising OH-Pdinteraction was discovered which might explain the differencein reactivity between the hydroxy- and methoxy-containingligands. The conformational change in the ligands due to thisinteraction may explain the different selectivities observed inthe catalytic reaction.

Polymer-bound pyridinooxazolines and bis(oxazolines) weresynthesised and employed in Pd-catalysed allylic alkylationswith results similar to those of monomeric analogues;enantioselectivities up to 95% were obtained. One polymer-boundligand could be re-used several times after removal of Pd(0).The polymer-bound bis(oxazoline) was also used in Zn-catalysedDiels-Alder reactions, but the heterogenised catalyst gavelower selectivities than a monomeric analogue.

A series of chiral dendron-containing pyridinooxazolines andbis(oxazolines) were synthesised and evaluated in Pd-catalysedallylic alkylations. The dendrons did not seem to have anyinfluence on the selectivity and little influence on the yieldwhen introduced in the pyridinooxazoline ligands. In thebis(oxazoline) series lower generation dendrimers had a postiveon the selectivity, but the selectivity and the activitydecreased with increasing generation.

Crown ether-containing ligands were investigated inpalladium-catalysed alkylations. No evidence of a possibleinteraction between the metal in the crown ether and thenucleophile was discovered.

A new type of catalyst, an oxazoline-containing palladacyclewas found to be very active in oxidations of secondary alcoholsto the corresponding aldehydes or ketones. The reactions wereperformed with air as the re-oxidant. Therefore, this is anenviromentally friendly oxidation method.

Keywords:asymmetric catalysis, chiral ligand,oxazolines, conformational study, allylic substitution,polymer-bound ligands, dendritic ligands, crown ether,oxidations, palladacycle.

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Newman, Louise M. „Asymmetric synthesis : approaches via enantiomerically pure acetal and oxazoline ligands“. Thesis, Loughborough University, 1999. https://dspace.lboro.ac.uk/2134/13773.

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This thesis describes the synthesis of novel ligands that include enantiomerically pure acetal and oxazoline moieties. These ligands are utilised in a number of metalmediated asymmetric syntheses. All asymmetric acetals and pyridine based acetals are synthesised in good yield in a single step from their corresponding enantiomerically pure diols. C2 symmetric bisacetals are investigated as ligands in the organolithium and Grignard additions to benzaldehyde with promising results. C2 symmetric bisacetals and pyridine based acetals are tested for their ability to induce asymmetry in copper(l) catalysed cyclopropanation of styrene using ethyl diazoacetate and the lanthanide(lII) catalysed Diels-Alder cycloaddition involving Danishefsky's diene with little success. Enantiomerically pure phosphinooxazoline ligands are available in good yield in two steps from their corresponding enantiomerically pure aminoalcohols. Enantiomerically pure acetal substituted pyridines and phosphinooxazoline ligands are considered in the rhodium (I) catalysed hydrosilylation of ketones. Reaction conditions for the more successful phosphinooxazoline ligands are optimised. Using these ligands a range of enantiomerically enriched alcohols is presented in good yield and enantiomeric excess. Novel phosphinooxazoline ligands are applied to the palladium(O) catalysed allylic substitution reaction with excellent enantioselectivities of the substitution product.

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Gillespie, Jason A. „Design and synthesis of wide bite angle phosphacyclic ligands“. Thesis, University of St Andrews, 2012. http://hdl.handle.net/10023/3100.

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By examining structure activity relationships for a given catalytic reaction it is possible to discover what ligand features and parameters lead to stable and highly active/selective catalyst systems. With this knowledge in hand it may be possible to rationally design next generation ligands and catalysts to affect improved substrate transformations, with higher selectivities and faster reaction times. The success of Burk's DuPhos ligands in asymmetric hydrogenation demonstrated that chiral phosphacycles can be a potent source of chiral induction, whilst in a similar vein the work of van Leeuwen and Kamer established the wide bite angle xanthene based ligands as excellent catalysts in a range of reactions including hydroformylation. In a preliminary study with Osborne they showed that combining these wide bite angle ligand backbones with Burk's phospholane moieties led to a new powerful ligand in asymmetric allylic substitution. To examine the potential of combining these two ligand features further we designed and synthesised nine new C2-symmetric bidentate wide bite angle bisphosphacyclic ligands, featuring phosphetane, phospholane or diazaphospholane rings, aiming at a wide diversity of steric and electronic properties. The application of these ligands as chiral auxiliaries in transition metal catalysed reactions, including; hydrogenation, hydrocyanation, hydroformylation and allylic alkylation has been investigated. Good to excellent enantioselectivities were observed in all reactions, with maximum ee's of 92.5% observed in hydrogenation, using N-(3,4-dihydro-1-napthalenyl)-acetamide as substrate, and of 96.2% in the alkylation of 1,3-diphenyl-2-propenyl acetate.

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Chamseddine, Yssam. „Sondes mecanistiques chirales et/ou regioselectivement deuteriees : application a l'etude de quelques processus de substitution nucleophile“. Paris 6, 1988. http://www.theses.fr/1988PA066133.

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Böhnisch, Torben. „C₂-Symmetric Pyrazole-Bridged Ligands and Their Application in Asymmetric Transition-Metal Catalysis“. Doctoral thesis, Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2015. http://hdl.handle.net/11858/00-1735-0000-0028-876A-6.

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Linstadt, Roscoe T. H. „A. Studies In The Allylic Substitution Chemistry Of Copper Hydride B. Stereoselective Silylcupration Of Conjugated Alkynes In Micellar Media C. Palladium-Catalyzed Synthesis Of 1,3-Butadienes and [3]-[6]Dendralenes D. Synthesis Of Small Molecule Underwater Adhesives Inspired By Mussels“. Thesis, University of California, Santa Barbara, 2017. http://pqdtopen.proquest.com/#viewpdf?dispub=10257794.

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Copper hydride (CuH) has been shown to enable a number of selective 1,2- and 1,4-reductions when complexed with the appropriate ligand, yet the allylic substitution chemistry of CuH has been much less studied. This dissertation describes the further study of CuH to perform sequential reductions on Morita-Baylis-Hillman (MBH) adducts. Specifically: I) Selectivity in the SN2’ reduction of MBH adducts was shown to be highly dependant on the nature of the ligand used. II) The reaction of MBH alcohols was shown to involve an initial dehydrogenative silylation with PMHS, where both the oligomeric nature and electronics of the initially formed trialkoxysilyl ether intermediate are important in determining both the observed stereoselectivity, and efficiency of the substitution. III) MBH ketones could be employed in tandem SN2’/1,2-reduction sequences to arrive at stereodefined allylic alcohols with central chirality.

Vinylsilanes are versatile intermediates in organic synthesis owing to numerous methods for their transformation into other functional groups that proceed with high stereoretention. While there are numerous methods to synthesize stereodefined vinylsilanes from alkynes, many existing methods require the use of highly reactive moisture intolerant reagents and harsh reaction conditions, features that limit the functionality that can be accommodated. Even fewer of these existing methods are conducted under environmentally responsible conditions. The use of Suginome’s reagent as a moisture tolerant source of nucleophilic silicon, small catalytic quantities of a simple copper(I) salt, and an aqueous solution of TPGS-750-M as an environmentally benign nonionic surfactant, is described herein as a highly effective combination of reagents that allows for the stereoselective silylcupration of conjugated alkynes giving access to a variety of (E)-β-silyl-substituted carbonyl derivatives under environmentally responsible conditions.

This dissertation also describes the application of substituted allenoates as electrophilic butadienyl coupling partners under palladium catalysis in aqueous micellar media. The substituted allenoates could then be transformed by the methods developed herein into a variety of 2-substituted butadienes, where the methods were then extended to provide entry into a variety of substituted [3]-[6]dendralenes. Specifically: I) Application of an additive based screen allowed for evaluation of functional group tolerance in the Pd-catalyzed coupling of substituted allenoates with boronic acids. II) Curiosity driven investigations to identify boron based sp3 coupling reagents compatible with the conditions of micellar catalysis led to the identification of OBBD alkylborinate reagents as stable and isolable coupling reagents, which was the applied to the synthesis of 2-alkyl 1,3-butadienes. III) An analogous vinylallenyl coupling partner that functions formally as an electrophilic [3]dendralene synthon was proposed, and a number of synthetic routes were examined to access this molecule. Optimization of the synthetic route allowed for access to multigram quantities of this material, where it was applied to the synthesis of variously substituted [3]-[6]dendralenes.

Efforts to understand the marine mussels mechanism of strong wet adhesion has been a subject of intense scientific investigation. Analysis of the peptide sequence of mfp-5, a mussel foot protein most correlated with interactions at the interface, revealed a high proportion of charged, hydrophobic, and catechol containing residues. Described in this dissertation is the synthesis of small molecule underwater adhesives by incorporation of these key features of mfp-5. These newly designed molecules formed adhesive bilayers underwater, and were shown to replicate and even exceed mfp-5’s strong wet adhesive energy, while also being orders of magnitude smaller than both the native mussel proteins or existing biomimetic adhesive platforms. By systematically varying key portions of these small molecular adhesives, the adhesive bilayers could be transformed into molecularly uniform monolayers which were applied to the nanofabrication of organic electronic devices.

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Rovira, González Laura. „Design and Application of Bisphosphite Ligands with a Distal Regulation Site for Asymmetric Catalysis“. Doctoral thesis, Universitat Rovira i Virgili, 2016. http://hdl.handle.net/10803/395211.

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S´ha estudiat el disseny i la síntesi de lligands supramoleculars enantiopurs de tipus bisfosfit, juntament amb les propietats de coordinació d’aquests lligands amb precursors de rodi i pal•ladi. Els complexes de rodi i pal•ladi derivats d’aquests lligands supramoleculars s’han aplicat com catalitzadors en hidroformilacions i substitucions al•líliques asimètriques. Els lligands dissenyats contenen una cadena polioxietilènica, que és la responsable de la regulació a través d'interaccions supramoleculars amb els agents de regulació, i a més contenen dos grups fosfit derivats de diols enantiomèricament purs que es coordinen amb el centre metàl•lic i constitueixen el centre catalític. L’estratègia supramolecular que s’ha emprat en la present Tesi Doctoral es basa en la interacció entre diversos agents de regulació (sals de metalls alcalins, alcalinoterris o lantànids) amb la cadena polioxietilènica del lligand, que serveix per a modificar la geometria i flexibilitat del centre catalític (efecte adaptatiu del catalitzador asimètric). L'ús d'aquesta estratègia de regulació supramolecular ha permès obtenir enantioselectivitats elevades en reaccions d´hidroformilació d’olefines heterocícliques. A més a més, s’ha pogut regular per alguns alquens heterocíclics la regioselectivitat de la reacció i s’ha pogut eliminar la formació de productes secundaris associats amb la reacció d’hidroformilació. Lligands supramoleculars regulables de tipus bisfosfit s’han aplicat també en substitucions al•líliques asimètriques. Els efectes de regulació que s’han obtingut en aquesta transformació han estat notables, tot i què les enantioselectivitats obtingudes han estat moderades.
Se ha estudiado el diseño y la síntesis de ligandos supramoleculares enantiopuros de tipo bisfosfito, juntamente con las propiedades de coordinación de estos ligandos con precursores de rodio y paladio. Los complejos de rodio y paladio derivados de estos ligandos supramoleculares se han aplicado como catalizadores en hidroformilaciones y substituciones alílicas asimétricas. Los ligandos diseñados contienen una cadena polioxietilénica, que es la responsable de la regulación a través de interacciones supramoleculares con los agentes de regulación, y que además contienen dos grupos fosfito derivados de dioles enantioméricamente puros que se coordinan al centro metálico y constituyen el centro catalítico. La estrategia supramolecular que se ha empleado en la presente Tesis Doctoral se basa en la interacción entre agentes de regulación diversos (sales de metales alcalinos, alcalinotérreos o lantánidos) con la cadena polioxietilénica del ligando, que sirve para modificar la geometría y flexibilidad del centro catalítico (efecto adaptativo del catalizador asimétrico). El uso de esta estrategia de regulación supramolecular ha permitido obtener enantioselectividades elevadas en reacciones de hidroformilación de olefinas heterocíclicas. Además, se ha podido regular para algunos alquenos heterocíclicos la regioselectividad de la reacción y se ha podido eliminar la formación de productos de isomerización asociados con la reacción de hidroformilación. Ligandos supramoleculares de tipo bisfosfito se han aplicado también en sustituciones alílicas asimétricas. Los efectos de regulación que se han obtenido en esta transformación han sido notables, aunque las enantioselectividades obtenidas han sido moderadas.
The design and synthesis of enantiopure supramolecular bisphosphite ligands, together with their coordination properties with rhodium and palladium precursors, have been studied. Rhodium and palladium complexes derived from these supramolecular ligands have been applied as catalysts in asymmetric hydroformylations and allylic substitutions. The designed ligands contain a polyoxyethylene motif, which is the responsible for regulation through supramolecular interactions with the regulation agents, and two phosphite groups derived from enantiomerically pure diol derivatives that bind the metal center and constitute the catalytic site. The supramolecular strategy that has been followed within the present Doctoral Thesis relies on the interaction between a number of regulation agents (alkali metal, alkaline earth metal or lanthanide salts) and the polyoxyethylene motif of the ligand, which serves for the fine modification of the geometry and flexibility of the catalytic center (adaptive effect of the asymmetric catalyst). This supramolecular regulation strategy has led to high enantioselectivities in hydroformylation reactions of heterocyclic olefins and has allowed the regulation of the regioselectivity in the hydroformylation of several cyclic olefins. Furthermore, the formation of byproducts associated with the hydroformylation process has also been suppressed with the use of the above mentioned regulation agents. Supramolecularly regulated bisphosphite ligands have also been applied to asymmetric allylic substitution reactions. Noteworthy regulation effects have been achieved in this transformation, though the enantioselectivies in the allylic substitutions remained moderate.

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