Download or read book Investigations in Iron Copper and Palladium catalyzed C H Bond Functionalization written by Ly Dieu Tran and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Transition metal-catalyzed functionalization of C-H bonds has been used as a powerful tool for the construction of C-C and C-heteroatom bonds. Within this dissertation, methods that allow functionalization of C-H bonds via iron and copper catalysis have been developed. Additionally, functionalization of sp3 C-H bonds in amino acid derivatives using auxiliary-assisted palladium-catalyzed methodology is also demonstrated. A method for iron-catalyzed alkylation of arenes and heterocycles containing acidic C-H bonds has been developed. Various heterocycles such as pyridine, furan, thiophene and electron deficient arenes can be coupled with both alkyl bromides and iodides. Magnesium amide base is required for the reaction. Similarly, the deprotonative dimerization of arenes and heterocycles can be effected in the presence of an iron catalyst. Thus, the method allows direct functionalization of arenes and heterocycles. Additionally, the use of an iron catalyst is an advantage compared with existing methods. Methods for copper-catalyzed direct sulfenylation and amination of sp2 C-H bonds have been developed. Using 8-aminoquinoline auxiliary and copper catalyst, ortho C-H bonds of benzoic acid amides can be sulfenylated by disulfides. The method provides an alternative, milder way for the preparation of aryl trifluoromethylsulfides. Furthermore, ortho C-H bonds of benzoic acid amides can be aminated by reaction with simple amines using 8-aminoquinoline directing group and a copper catalyst. Sulfenylation and amination of g-C-H bonds of benzyl amine derivatives using picolinic acid auxiliary were also demonstrated. Broad substrate scope, high regioselectivity, and good functional group tolerance were observed. The use of a copper catalyst and a removable directing group are significant improvements compared with the existing methods. Finally, a novel way for synthesis of non-natural amino acids via auxiliary-assisted, palladium-catalyzed C-H functionalization methodology was developed. Under palladium catalysis, 2-methyl thioaniline auxiliary allows the monoarylation of b-C-H bonds of alanine derivatives generating, after directing group removal, substituted phenylalanines. In contrast, using 8-aminoquinoline auxiliary, methylene groups in phenylalanine, leucine, and lysine derivatives can be arylated. Methods for alkylation and acetoxylation were also reported. The directing group can be removed without significant erosion of enantiomeric excess. The method provides a straight-forward way to synthesize non-natural amino acids from the chiral pool.
Download or read book Palladium Catalyzed C H Functionalization Studies Toward Ginkgolide C written by David Lapointe and published by LAP Lambert Academic Publishing. This book was released on 2012-06-01 with total page 320 pages. Available in PDF, EPUB and Kindle. Book excerpt: The field of metal-catalyzed C H bond functionalizations is an incredibly vibrant and spans beyond the formations of biaryl motifs. The mechanistic aspects of the C H bond functionalization with metal-carboxylate complexes are highlighted. The role of additives, such as pivalic acid, is demonstrated with poorly reactive substrates. A chapter describes experimental and computational studies which suggested that a single pathway might be involved in the palladium-catalyzed C H bond functionalization of a wide range of (hetero)arenes. Afterward a general set of conditions are developed to form biaryls by direct arylation with a wide range of heteroarenes of various complexity level. The development of two new Pd-catalyzed methods based on our knowledge on the C H bond cleavage are apply to the formation of new scaffolds. Efforts toward the development of ligands to specifically promoted C H bond cleavage are presented. Lastly, most recent results on the study of the mechanism of the C H bond cleavage combining experimental and computational studies are discussed. In the second part of the thesis are presented our strategy toward the synthesis of ginkgolide C using gold catalysis.
Download or read book Computational Investigations of Pd Catalyzed C H Functionalization Reactions written by Katherine Lynn Bay and published by . This book was released on 2020 with total page 138 pages. Available in PDF, EPUB and Kindle. Book excerpt: The use of an inert C-H bond towards the generation of a functional group is advantageous, as these bonds are the most abundant chemical moieties in organic molecules. A one-step conversion of a C-H bond to the desired functionality reduces the number of synthetic steps, which in turn minimizes the use of costly reagents, solvent, and time. Selective activation of a particular C-H bond in an organic molecule where C-H bonds are ubiquitous, however, is a challenging task. Among the most challenging aspects of developing robust C-H functionalization methodologies is identifying catalyst and reagent combinations capable of site-selective as well as stereoselective reactions. Therefore, directed C-H bond functionalization using a directing group and a suitable transition metal is of current interest. Palladium complexes are highly selective and have shown efficiency in various areas of organic synthesis, which make palladium catalysts particularly useful in the field of C-H functionalization. Palladium is incredibly powerful for the construction of carbon-carbon and carbon-heteroatom bonds by C-H activation of aryl and alkyl groups. Palladium-catalyzed ligand-directed C-H functionalization is a key goal towards the synthesis of complex multifunctional substrates. Understanding the mechanism and origins of stereoselectivity of palladium-catalyzed C-H functionalization reactions is essential to progress this field. The collaboration between experiment and computations has provided a deeper mechanistic understanding and insight than any of the isolated techniques can provide. Kinetics and isolation of intermediates provide information on mechanistic pathways, while computations can provide details of both structures and energetics in specific steps in the whole catalytic cycle. Computations have become vital to elucidate structures of molecules, mechanisms, and selectivities of reactions. Due to the rapid development of hardware, software, and theoretical methods, computational chemistry has evolved into a very powerful and routine tool to study complex mechanisms. The work in this thesis has stemmed from several collaborations through the NSF Center for Selective C-H Functionalization (CCHF), which is comprised of synthetic methodologists, physical organic chemists, catalyst developers, enzymologists, computational chemists, and several partners in the pharmaceutical industry. Motivated by the potential of understanding C-H functionalization transformations in order to promote the development of new reactions, this thesis focuses on using computational methods to understand systems of relevance to C-H activation using palladium as a catalyst. Early projects aim to use computations to make proposed models for nonlinear effects to serve as a meaningful mechanistic probe for predicting reaction kinetics (Chapters 1-2). The second section delves into elucidating the mechanisms as well as the role of various substrates, ligands, and oxidants, particularly silver (I) acetate, on how each particular reaction is performed (Chapters 3-6). Later in this thesis, the focus diverges to highlight the elucidation of an enantioselective -C-H functionalization where stereoselectivity arises from attractive aryl-aryl interactions (Chapter 7).
Download or read book Transition Metal Catalyzed Oxidative Cross Coupling Reactions written by Aiwen Lei and published by Springer. This book was released on 2018-12-14 with total page 192 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is a comprehensive text covering the research and development trends in the booming field of transition metal catalyzed oxidative cross-coupling reactions. Oxidative cross-coupling reaction is a new method to forming chemical bonds besides the traditional cross-coupling reactions. This book provides the answers to how this coupling reaction occurs and what its advantages are. The palladium, copper and iron catalyzed oxidative cross-coupling reactions as the main focuses of interest are described in detail. The oxidative cross-coupling reactions catalyzed by other metals and transition-metal-free oxidative coupling reactions are also introduced.This book provides a useful reference source for researchers and graduates in the field of transition metal catalyzed coupling reactions. It is also valuable to researchers working in pharmaceutical companies, fine organic chemical companies, and etc.
Download or read book C H and C X Bond Functionalization written by Xavi Ribas and published by Royal Society of Chemistry. This book was released on 2013-05-24 with total page 489 pages. Available in PDF, EPUB and Kindle. Book excerpt: Cross-coupling reactions involving C-H and C-X bond functionalisation are commonplace in natural product synthesis and natural products, therapeutic agents, biological probes, and advanced materials. Much attention has been given to understanding the mechanistic strategies used to achieve this, making this a hot topic in recent years. In this edited book, contributions from across the globe examine these strategies, with a particular focus on palladium and copper, as well as iron – an emerging element in this field. Reviewing the recent literature, the book presents an in-depth understanding of the field, guiding the reader to achieving the best synthetic strategies for aromatic functionalisation. Organic and Organometallic chemists, as well as natural product and pharmaceutical scientists, will find this an essential guide to a major transformation currently underway in synthetic chemistry.
Download or read book Strategies for Palladium Catalyzed Non directed and Directed C bond H Bond Functionalization written by Anant R. Kapdi and published by Elsevier. This book was released on 2017-05-23 with total page 502 pages. Available in PDF, EPUB and Kindle. Book excerpt: Strategies for Palladium-Catalyzed Non-directed and Directed C-H Bond Functionalization portrays the complete scope of these two aspects of C-H bond functionalization in a single volume for the first time. Featured topics include the influence of palladacyclic systems in C-H bond functionalization (need for newer catalytic systems for better efficiency), mechanistic aspect of the functionalization strategies leading to better systems, and applications of these methodologies to natural product synthesis and material synthesis. Addresses the involvement of catalytic systems (palladacycles) for better functionalization of (hetero)arenes to emphasize the need for developing better, more selective systems Covers the use of powerful mechanistic tools for understanding and assisting the development of better functionalization strategies Discusses the finer aspects of C-H bond functionalization, such as control of regioselectivity with or without directing groups Includes a chapter detailing the synthesis of naturally occurring molecules or functional molecules via both pathways for assessing the applicability of the functionalization strategies
Download or read book C H Bond Activation and Catalytic Functionalization I written by Pierre H. Dixneuf and published by Springer. This book was released on 2015-12-18 with total page 269 pages. Available in PDF, EPUB and Kindle. Book excerpt: The series Topics in Organometallic Chemistry presents critical overviews of research results in organometallic chemistry. As our understanding of organometallic structure, properties and mechanisms increases, new ways are opened for the design of organometallic compounds and reactions tailored to the needs of such diverse areas as organic synthesis, medical research, biology and materials science. Thus the scope of coverage includes a broad range of topics of pure and applied organometallic chemistry, where new breakthroughs are being achieved that are of significance to a larger scientific audience. The individual volumes of Topics in Organometallic Chemistry are thematic. Review articles are generally invited by the volume editors. All chapters from Topics in Organometallic Chemistry are published OnlineFirst with an individual DOI. In references, Topics in Organometallic Chemistry is abbreviated as Top Organomet Chem and cited as a journal.
Download or read book Palladium and Nickel Catalyzed Transformations Forming Functionalized Heterocycles written by Hyung Yoon and published by Springer Nature. This book was released on 2020-09-02 with total page 236 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents Pd- and Ni-catalyzed transformations generating functionalized heterocycles. Transition metal catalysis is at the forefront of synthetic organic chemistry since it offers new and powerful methods to forge carbon–carbon bonds in high atom- and step-economy. In Chapter 1, the author describes a Pd- and Ni-catalyzed cycloisomerization of aryl iodides to alkyl iodides, known as carboiodination. In the context of the Pd-catalyzed variant, the chapter explores the production of enantioenriched carboxamides through diastereoselective Pd-catalyzed carboiodination. It then discusses Ni-catalyzed reactions to generate oxindoles and an enantioselective variant employing a dual ligand system. Chapter 2 introduces readers to a Pd-catalyzed diastereoselective anion-capture cascade. It also examines diastereoselective Pd-catalyzed aryl cyanation to synthesize alkyl nitriles, a method that generates high yields of borylated chromans as a single diastereomer, and highlights its synthetic utility. Lastly, Chapter 3 presents a Pd-catalyzed domino process harnessing carbopalladation, C–H activation and π-system insertion (benzynes and alkynes) to generate spirocycles. It also describes the mechanistic studies performed on these reactions.
Download or read book Part A written by David Lapointe and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Investigation in Directed Metal catalyzed C H Bond Functionalization written by Yousuf Mohammed Al-Lawati and published by . This book was released on 2019 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Mizoroki Heck Reaction written by Martin Oestreich and published by John Wiley & Sons. This book was released on 2009-02-11 with total page 608 pages. Available in PDF, EPUB and Kindle. Book excerpt: Exploring the importance of Richard F. Heck’s carbon coupling reaction, this book highlights the subject of the 2010 Nobel Prize in Chemistry for palladium-catalyzed cross couplings in organic synthesis, and includes a foreword from Nobel Prize winner Richard F. Heck. The Mizoroki-Heck reaction is a palladium-catalyzed carbon–carbon bond forming process which is widely used in organic and organometallic synthesis. It has seen increasing use in the past decade as chemists look for strategies enabling the controlled construction of complex carbon skeletons. The Mizoroki-Heck Reaction is the first dedicated volume on this important reaction, including topics on: mechanisms of the Mizoroki-Heck reaction intermolecular Mizoroki-Heck reactions focus on regioselectivity and product outcome in organic synthesis waste-minimized Mizoroki-Heck reactions intramolecular Mizoroki-Heck reactions formation of heterocycles chelation-controlled Mizoroki-Heck reactions the Mizoroki-Heck reaction in domino processes oxidative heck-type reactions (Fujiwara-Moritani reactions) Mizoroki-Heck reactions with metals other than palladium ligand design for intermolecular asymmetric Mizoroki-Heck reactions intramolecular enantioselective Mizoroki-Heck reactions desymmetrizing Mizoroki-Heck reactions applications in combinatorial and solid phase syntheses, and the development of modern solvent systems and reaction techniques the asymmetric intramolecular Mizoroki-Heck reaction in natural product total synthesis Several chapters are devoted to asymmetric Heck reactions with particular focus on the construction of otherwise difficult-to-obtain sterically congested tertiary and quaternary carbons. Industrial and academic applications are highlighted in the final section. The Mizoroki-Heck Reaction will find a place on the bookshelves of any organic or organometallic chemist. “I am convinced that this book will rapidly become the most important reference text for research chemists in academia and industry who seek orientation in the rapidly growing and – for the layman – confusing field described as the “’Mizoroki–Heck reaction’.” (Synthesis, March 2010)
Download or read book Copper and Palladium Catalyzed Benz fused Heterocycle Synthesis Via Intramolecular Cross Coupling and C H Bond Functionalization Strategies written by Laurie Lynn Joyce and published by . This book was released on 2009 with total page 906 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis is a summary of research conducted in the laboratory of Professor Robert A. Batey at the University of Toronto. The manuscript is divided into three chapters.Chapter one gives a general overview of methods for metal-catalyzed synthesis of heterocycles through carbon-heteroatom (C--Y) bond-forming events.Chapter two describes the intramolecular copper-catalyzed synthesis of 2aminobenzoxazoles through the coupling of aryl bromides with ureas. Reaction conditions were optimized through studies examining the effect of changing various reaction parameters including temperature, catalyst and ligand loadings, solvent choice, and degree of dryness of the reaction system. Optimized reaction conditions involve heating o-bromophenylurea precursors with 10 mol% copper iodide and 20 mol% 1,10-phenanthroline ligand in the presence of the weak base CS2CO3 (1.2 equiv) in a 1:1 acetonitrile:xylenes solvent system at 110-120°C to give 2-aminobenzoxazole products in good to excellent conversions and yields for a reaction time of 24 hours, These reactions were found to require strictly anhydrous reaction conditions and are effective only for N,N',N'-trisubstituted o-bromophenylureas.Chapter three describes a novel paliadium(0) catalyzed intramolecular oxidative C--H bond functionalization/C--S bond formation reaction for the synthesis of 2aminobenzothiazoles and related heterocycles. Reaction optimization studies were conducted by examining the effect of changing various reaction parameters while monitoring the progress of the reactions using HPLC. Optimized reaction conditions involve heating arylthiourea substrates with 3 mol% palladium tetrakistriphenylphosphine with activated 10 mol% manganese dioxide in acetonitrile solvent under an oxygen atmosphere at 80°C to give cyclized 2-aminobenzothiazole products in excellent yields. Anhydrous reaction conditions are required, and only N,N',N'-trisubstituted phenylthioureas were found to be suitable precursors to 2aminobenzothiazoles. This methodology offers improved efficiency and atom economy over previous metal-catalyzed methods that require ortho-halo arylthiourea precursors, thereby significantly improving the availability of phenylthiourea starting materials. Unlike for other palladium-catalyzed C--H functionalization reactions typically utilizing Pd(II) and a co-oxidant such as Cu(OAc)2 under oxidative conditions, we propose that the main role of activated MnO 2 is to act as a porous surface/sink to adsorb oxygen and deliver it to paliadium(0) to form a peroxo-paliadium(II) species.
Download or read book Palladium Catalyzed C H Bond Functionalization and Iron Catalyzed Addition and Annulation Reactions written by 甘迪潘 and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Europe the Way Ahead written by Organisation for European Economic Co and published by Hassell Street Press. This book was released on 2021-09-09 with total page 372 pages. Available in PDF, EPUB and Kindle. Book excerpt: This work has been selected by scholars as being culturally important and is part of the knowledge base of civilization as we know it. This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. To ensure a quality reading experience, this work has been proofread and republished using a format that seamlessly blends the original graphical elements with text in an easy-to-read typeface. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Download or read book Chelation assisted Palladium catalyzed Activation of C H Bonds written by Ramesh Giri and published by . This book was released on 2009 with total page 1280 pages. Available in PDF, EPUB and Kindle. Book excerpt: Carbon-hydrogen (C-H) bonds are ubiquitous in organic molecules. Utilization of such abundant chemical moieties as functional group equivalents could shorten route to synthetic targets and provide chemists with new disconnections in retrosynthesis. As such regio- and stereoselective functionalization of unactivated C-H bonds has remained one of the major challenges in organic chemistry. The majority of the transition metals have been rigorously examined for their efficacy in transforming unactivated C-H bonds (pKa >35) into useful functional groups or into C-C bonds. Among those metals, palladium is particularly effective in activating both aromatic (sp2) and aliphatic (sp3) C-H bonds. This thesis explores the reactivity of palladium catalysts in both of these areas. The research herein was conducted using directing groups for C-H cleavage with special focus on utilizing simple functionality such as carboxylic acids. Chapter one details different types of directing groups and their utility in a variety of reactions. Chapters two and three contain details of research on C-heteroatom (C-I and C-O) and C-C bond formation, respectively, with palladium acetate as a catalyst. The iodination and acetoxylation reactions proceed under mild conditions and moderate to excellent levels of diastereoselectivity (up to 99.9%) have been observed with both sp2 and sp3 C-H bonds using oxazoline as the directing group. Mechanistic investigations have been carried out in order to understand the high level of stereoselection and, in this process, a number of palladacycle intermediates have been characterized by X-ray crystallography which led us to assign the absolute stereochemistry of C-H activation. Moreover, the iodination protocol could also be extended to prepare diiodides as intermediates for cyclopropanation which provides a new disconnection approach to construct cyclopropanes. Chapter two discusses C-C bond formation via cross-coupling reactions with organoboron reagents and carbon monoxide using the carboxylic acids as the directing group. Detailed mechanistic investigation along with characterization of intermediate palladacycle formed from sodium toluate have revealed an unprecendented directing ability of carboxylate groups in which the carbonyl oxygen, rather than the O-anion, directs palladium for C-H cleavage.
Download or read book Catalytic C H Bond Functionalization Reactions Catalyzed by Rhodium iii Porphyrin Palladium ii and Platinum ii Acetate Complexes written by Hung-Yat Thu and published by Open Dissertation Press. This book was released on 2017-01-27 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation, "Catalytic C-H Bond Functionalization Reactions Catalyzed by Rhodium(III) Porphyrin, Palladium(II) and Platinum(II) Acetate Complexes" by Hung-yat, Thu, 杜鴻溢, was obtained from The University of Hong Kong (Pokfulam, Hong Kong) and is being sold pursuant to Creative Commons: Attribution 3.0 Hong Kong License. The content of this dissertation has not been altered in any way. We have altered the formatting in order to facilitate the ease of printing and reading of the dissertation. All rights not granted by the above license are retained by the author. Abstract: Abstract of thesis entitled CATALYTIC C-H BOND FUNCTIONALIZATION REACTIONS CATALYZED BY RHODIUM(III) PORPHYRIN, PALLADIUM(II) AND PLATINUM(II) ACETATE COMPLEXES Submitted by Thu Hung Yat For the degree of Doctor of Philosophy at The University of Hong Kong in December 2006 This work describes C-N and C-C bond formation reactions via the selective functionalization of C-H bonds. The metal-catalyzed nitrene transfer reaction for C-N bond formation has been extensively investigated; however, these reactions are applicable only for activated C-H bonds. Inspired by the recent development in chelation-directed C-H bond functionalization reactions, it was found that Pd(OAc) 2 2 3 would catalyze the intermolecular amidation reactions of unactivated sp and sp C-H bonds using primary amides and potassium persulfate. The substrates containing a pendant oxime or pyridine group were amidated with excellent chemo- and regioselectivities. Reactive C-X bonds are well-tolerated under the Pd-catalyzed reaction conditions. Primary amides are effective nucleophiles for the Pd-catalyzed 3 o amidation reactions. For the reaction of unactivated sp C-H bonds, β-amidation of 1 o C-H bonds versus 2 C-H bonds is preferred. The catalytic reaction is initiated by chelation-assisted cyclopalladation involving C-H bond activation. A preliminary mechanistic study suggested that the persulfate oxidation of primary amides generate reactive nitrene species, which then react with the cyclopalladated complex. Employing the reaction protocol, intermolecular amidation of C-H bonds without directing element has been examined. With benzene as the substrate, the corresponding amide product was obtained in 15% yield. Stereoselective C-C bond formation via metal-carbenoid transfer to C-H bonds has been achieved. In this work, [Rh(Por)CH ] (Por = Porhyrinato dianion) are effective catalysts for diastereoselective and enantioselective inter- and intramolecular carbenoid insertion to saturated C-H bonds. Yields of > 94% with > 99% stereoselectivity have been attained in the Rh-catalyzed intramolecular cyclization of α-diazoacetamides to the corresponding cis-β-lactams and trans-γ-lactams. Moreover, the [Rh(TTP)CH ] [TTP = meso-tetrakis(p-toly)porphyrin] complex could be reused without significant deterioration of the catalytic activity; turnover numbers of up to 8558 have been accomplished for catalyst with five consecutive reaction runs. Moreover, the [Rh(Por)CH ] complexes are effective catalysts for intermolecular insertion to unactivated C-H bonds of cycloalkanes and n-alkanes. Employing hindered methyl phenyldiazoacetate as carbene source and sterically bulky [Rh(TTPPP)(Cl)(OH )] [TTPPP = meso-tetrakis(2,4,6-triphenyl)porphyrin] as catalyst, selective carbenoid o o o insertion to 1 C-H bonds (1: 2 = 11.2 for n-hexane) was achieved. The insertion reactions were proposed to proceed via a Rh(III) porphyrin carbene intermediate and + the structure of a related [Rh(TTP)(CH )(CH CO Et)] adduct was described. DFT 3 2 2 calculation on a rhodium(III) porphyrin carbene model complex revealed strong single bond character of the Rh-C bond. Results demonstrated the ability of carbenerhodium(III) porphyrins as a new class of versatile catalysts for inter- and intramolecular carbenoid C-H insertion reaction
Download or read book Metal Catalyzed Cross Coupling Reactions and More written by Armin de Meijere and published by John Wiley & Sons. This book was released on 2013-12-04 with total page 1640 pages. Available in PDF, EPUB and Kindle. Book excerpt: This three volume book is the follow-up handbook to the bestselling volume "Metal-Catalyzed Cross-Coupling Reactions", the definitive reference in the field. In line with the enormous developments in this area, this is not a new edition, but rather a new book in three volumes with over 50% more content. This new content includes C-H activation, shifting the focus away from typical cross-coupling reactions, while those topics and chapters found in de Meijere/Diederich's book have been updated and expanded. With its highly experienced editor team and the list of authors reading like an international Who's-Who in the field, this work will be of great interest to every synthetic chemist working in academia and industry.
