Download or read book Transition Metal Catalyzed Ring opening Reactions of Unsymmetrical Oxabicyclic Alkenes written by Raheem Mohammed Abdul and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Rhodium Catalyzed Asymmetric Ring Opening of Oxabicyclic Alkenes and Palladium Catalyzed Carbon Halogen Bond Forming Reactions written by Christine Le and published by . This book was released on 2017 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Atom-economical addition reactions to unsaturated carbonâ carbon bonds represent a powerful class of transformations in organic chemistry, since a great deal of molecular complexity can be generated from simple starting materials. Highly regio- and stereoselective processes have been made possible through the use of transition metal catalysts, alongside specialized ancillary ligands and in combination with rational substrate design. One area of research in the Lautens group involves the transition metal catalyzed asymmetric ring opening (ARO) of strained alkenes, which provides access to enantioenriched carbocyclic frameworks. Although a variety of coupling partners have been applied in this transformation, the use of soft carbon nucleophiles remains limited in scope. The first chapter describes a rhodium(I)-catalyzed ARO of meso-oxabicyclic alkenes using silyl enol ethers and ketene acetals. In analogy to the Mukaiyama aldol reaction, a novel silyl migration occurs, enabling an in situ protection of the chiral alcohols obtained. Developing new reactivity from Heck-type carbopalladation processes represents another research interest in the Lautens group. Oxidative addition into a carbonâ halogen bond constitutes the first step of nearly all palladium(0)-catalyzed cross-couplings. Conversely, reductive elimination from palladium(II) to yield an organohalide product represents a rare and often thermodynamically unfavoured process. The next two chapters address challenges in the synthesis of vinyl halides using palladium(0) catalysis via the intramolecular carbohalogenation and chlorocarbamoylation of alkynes. During our investigations, we discovered that the steric bulk of both the substrate and the phosphine ligand play an important role in promoting the desired reactivity. Mechanistic insight has been gained through combined experimental and computational studies, which implicate a palladium-catalyzed stereoisomerization in both of these transformations. Under certain conditions, we demonstrate that highly stereoselective trans-additions to alkynes can be achieved, which illustrates that specific substrate/catalyst combinations can override the inherent cis-selectivity in carbometallations. In the fourth chapter, a formal palladium(II)-catalyzed alkyne chlorocarbamoylation reaction is presented, which provides access to medicinally relevant methylene oxindole scaffolds. In contrast to the analogous protocol using palladium(0) catalysts, the reaction is initiated by an alkyne chloropalladation step, followed by intramolecular cross-coupling with a carbamoyl chloride. Experimental and computational studies provide insight into the mechanism of this reaction.
Download or read book Investigation of Transition Metal catalyzed Ring Opening Reactions of Bicyclic Alkenes written by University of Guelph. Dept. of Chemistry and Biochemistry and published by . This book was released on 2009 with total page 139 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Rhodium Catalyzed Enantioselective Desymmetrizations of Oxabicyclic Alkenes and Alkene Difunctionalization Via Nickel Catalyzed Arylcyanation written by Andy Wei Jen Yen and published by . This book was released on 2020 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The synthesis of heterocycles using transition metal catalysis is a topic of broad interest in the field of organic chemistry. Transition metal catalysts allow many diverse bond disconnections to be realized, allowing for many ways to assemble heterocycles. Many of the transformations developed in the Lautens group are aimed at atom economical bond construction processes that streamline synthesis and minimize waste. The arylcyanation reaction and the asymmetric ring opening (ARO) reaction are two examples of methods developed in our group that embody this design principle. Chapter 1 of this thesis describes the development of a nickel-catalyzed arylcyanation reaction for the synthesis of 3,3-disubstituted oxindoles. This method was inspired by our work on the palladium-catalyzed arylcyanation reaction, originally developed to address challenges in the formal synthesis of (+)-corynoline. This nickel-catalyzed reaction uses an air-stable catalyst precursor to achieve a highly practical synthesis of a nitrile-containing oxindole via a domino Heck-cyanide capture cascade. Derivatizations of the nitrile group affords a series of novel heterocyclic scaffolds. Chapter 2 details the discovery and development of a novel enantioselective cycloisomerization reaction of oxabicyclic alkenes. Our work on developing the intramolecular asymmetric ring opening reaction led to the discovery of a novel epoxide synthesis. Specifically, when bridgehead substituted oxabicyclic alkenes with non-nucleophilic side chains are reacted with the [Rh(cod)2]OTf/PPF-PtBu2 catalyst in the absence of an external nucleophile, chiral epoxides are obtained. The synthesis of epoxides through cycloisomerization reactions possesses 100% atom economy and avoids the use of external oxidant. Chapter 3 describes an asymmetric ring opening reaction, specifically to address gaps in the methodology concerning amine nucleophiles. We were inspired by our group's previous attempts to use amino acid derived nucleophiles in the ARO reaction. We developed a way to incorporate amino acids into the ARO reaction by employing their 2-nitrobenzenesulfonamide (nosyl) derivatives as pronucleophiles. Intriguingly, we observed a divergence in reactivity between the diastereomeric hydroxyester products, in that one diastereomer was capable of lactonization and the other was not. This led to the enantioselective synthesis of chiral oxazinones, which are similar to the naphthoxazine class of compounds which possess dopaminergic activity.
Download or read book Fundamentals of Asymmetric Catalysis written by Patrick J. Walsh and published by University Science Books. This book was released on 2009-01-02 with total page 692 pages. Available in PDF, EPUB and Kindle. Book excerpt: This work describes the essential aspects of enantioselective catalysis, with chapters organised by concept rather than by reaction type. Each concept is supported by examples to give the reader broad exposure to a wide range of catalysts, reactions and reaction mechanisms.
Download or read book Iridium catalyzed asymmetric ring opening reactions of oxabicyclic alkenes with secondary amine nucleophiles written by and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Inter and Intramolecular Ring Opening Reactions of Oxabicyclic Substrates written by Christopher Wicks and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Oxabenzonorbornadiene (OBD) and derivatives thereof have become key substrates of interest within synthetic organic chemistry and natural product synthesis as they enable the formation of multiple stereocenters in a single transformation. The present work expands on previous studies to investigate various intramolecular transformations, and regiochemical implications regarding ring-opening reactions of asymmetric oxabicyclic alkenes. Acid-catalyzed intramolecular ring-opening reactions of cyclopropanated oxabenzonorbornadiene (CPOBD) derivatives were investigated to afford novel medium-sized ring systems in moderate to good yields and good to excellent regioselectivity. Similarly, a Ni catalyzed intramolecular ring-opening reaction of alkyl halide tethered OBD compounds was optimized, thus generating a naphthalene derivative in excellent yields. Lastly, iridium-catalyzed ring-opening reactions of unsymmetrical C1-substituted OBD derivatives is presented using alcohols and water as nucleophiles which allows for the selective synthesis of previously inaccessible substrates.
Download or read book Transition Metal Catalyzed Enantioselective Allylic Substitution in Organic Synthesis written by Uli Kazmaier and published by Springer Science & Business Media. This book was released on 2011-10-29 with total page 354 pages. Available in PDF, EPUB and Kindle. Book excerpt: Giovanni Poli, Guillaume Prestat, Frédéric Liron, Claire Kammerer-Pentier: Selectivity in Palladium Catalyzed Allylic Substitution.- Jonatan Kleimark and Per-Ola Norrby: Computational Insights into Palladium-mediated Allylic Substitution Reactions.- Ludovic Milhau, Patrick J. Guiry: Palladium-catalyzed enantioselective allylic substitution.- Wen-Bo Liu, Ji-Bao Xia, Shu-Li You: Iridium-Catalyzed Asymmetric Allylic Substitutions.- Christina Moberg: Molybdenum- and Tungsten-Catalyzed Enantioselective Allylic Substitutions.- Jean-Baptiste Langlois, Alexandre Alexakis: Copper-catalyzed enantioselective allylic substitution.- Jeanne-Marie Begouin, Johannes E. M. N. Klein, Daniel Weickmann, B. Plietker: Allylic Substitutions Catalyzed by Miscellaneous Metals.- Barry M. Trost, Matthew L. Crawley: Enantioselective Allylic Substitutions in Natural Product Synthesis.
Download or read book Nickel catalyzed Asymmetric Reductive Ring Opening of Oxabicyclic Alkenes written by and published by . This book was released on 1998 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Earth Abundant Transition Metal Catalyzed Reactions written by and published by Elsevier. This book was released on 2024-09-18 with total page 270 pages. Available in PDF, EPUB and Kindle. Book excerpt: Earth-Abundant Transition Metal Catalyzed Reactions, Volume 74 in the Advances in Catalysis series, highlights new advances in the field, with this new volume presenting interesting chapters. Each chapter is written by an international board of authors. Chapters in this new release include in Chiral Iron Complexes for Asymmetric Catalysis, Recent advances in Ni-catalyzed Functionalization of Strong C-O and C-H Bonds, Low-valent Molecular Cobalt Complexes for Reductive Chemistry, Iron-catalyzed group-transfer reactions with hypervalent iodine reagents, and Iron Porphyrins for Mediating Atom Efficient C–C Bond Formations. Provides the authority and expertise of leading contributors from an international board of authors Presents the latest release in Advances in Catalysis serials Updated release includes the latest information in the field
Download or read book Transition Metal Catalyzed Carbonylative Synthesis of Heterocycles written by Xiao-Feng Wu and published by Springer. This book was released on 2015-12-14 with total page 176 pages. Available in PDF, EPUB and Kindle. Book excerpt: The series Topics in Heterocyclic Chemistry presents critical reviews on present and future trends in the research of heterocyclic compounds. Overall the scope is to cover topics dealing with all areas within heterocyclic chemistry, both experimental and theoretical, of interest to the general heterocyclic chemistry community. The series consists of topic related volumes edited by renowned editors with contributions of experts in the field. All chapters from Topics in Heterocyclic Chemistry are published Online First with an individual DOI. In references, Topics in Heterocyclic Chemistry is abbreviated as Top Heterocycl Chem and cited as a journal.
Download or read book Ring Opening Reactions of Small Heterocyclic Compounds Catalyzed by Transition Metal Complexes written by Kellie Marie Brosius and published by . This book was released on 2002 with total page 306 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Transition Metal Catalysed Reactions written by International Union of Pure and Applied Chemistry and published by . This book was released on 1999 with total page 524 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Copper Catalyzed Asymmetric Synthesis written by Alexandre Alexakis and published by John Wiley & Sons. This book was released on 2013-12-30 with total page 467 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book reflects the increasing interest among the chemical synthetic community in the area of asymmetric copper-catalyzed reactions, and introduces readers to the latest, most significant developments in the field. The contents are organized according to reaction type and cover mechanistic and spectroscopic aspects as well as applications in the synthesis of natural products. A whole chapter is devoted to understanding how primary organometallics interact with copper to provide selective catalysts for allylic substitution and conjugate addition, both of which are treated in separate chapters. Another is devoted to the variety of substrates and experimental protocols, while an entire chapter covers the use on non-carbon nucleophiles. Other chapters deal with less-known reactions, such as carbometallation or the additions to imines and related systems, while the more established reactions cyclopropanation and aziridination as well as the use of copper (II) Lewis acids are warranted their own special chapters. Two further chapters concern the processes involved, as determined by mechanistic studies. Finally, a whole chapter is devoted to the synthetic applications. This is essential reading for researchers at academic institutions and professionals at pharmaceutical or agrochemical companies.
Download or read book Transition Metal Mediated Aromatic Ring Construction written by Ken Tanaka and published by John Wiley & Sons. This book was released on 2013-07-09 with total page 785 pages. Available in PDF, EPUB and Kindle. Book excerpt: State-of-the-science methods, synthetic routes, and strategies to construct aromatic rings The development of new reactions for the synthesis of aromatic compounds is a highly active research area in organic synthesis, providing new functional organic materials, functional reagents, and biologically active compounds. Recently, significant advances in transition-metal-mediated reactions have enabled the efficient and practical construction of new aromatic rings with useful properties and applications. This book draws together and reviews all the latest discoveries and methods in transition-metal-mediated reactions, offering readers promising new routes to design and construct complex aromatic compounds. Integrating metal catalysis with aromatic compound synthesis, Transition-Metal-Mediated Aromatic Ring Construction offers a practical guide to the methods, synthetic routes, and strategies for constructing aromatic compounds. The book's five parts examine: [2+2+2], [2+2+1], and related cycloaddition reactions [4+2], [3+2], and related cycloaddition reactions Electrocyclization reactions Coupling and addition reactions Other important transformations, including methathesis reactions and skeletal rearrangement reactions Edited by Ken Tanaka, an internationally recognized expert in the field of transition-metal catalysis, the book features authors who are leading pioneers and researchers in synthetic reactions. Their contributions reflect a thorough review and analysis of the literature as well as their own firsthand laboratory experience developing new aromatic compounds. All chapters end with a summary and outlook, setting forth new avenues of research and forecasting new discoveries. There are also references at the end of each chapter, guiding readers to important original research reports and reviews. In summary, Transition-Metal-Mediated Aromatic Ring Construction offers synthetic chemists a promising new avenue for the development of important new aromatic compounds with a broad range of applications.
Download or read book New Pathways for Organic Synthesis written by H.M. Colquhoun and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 459 pages. Available in PDF, EPUB and Kindle. Book excerpt: The continually growing contribution of transition metal chemistry to synthetic organic chemistry is, of course, widely recognized. Equally well known is the difficulty in keeping up-to-date with the multifarious reactions and procedures that seem to be spawned at an ever-increasing rate. These can certainly be summarized on the basis of reviews under the headings of the individual transition metals. More useful to the bench organic chemist, however, would be the opposite type of concordance based on the structural type of the desired synthetic product. This is the approach taken in the present monograph, which presents for each structural entity a conspectus of the transition metal-mediated processes that can be employed in its production. The resulting comparative survey should be a great help in devising the optimum synthetic approach for a particular goal. It is presented from an essentially practical viewpoint, with detailed direc tions interspersed in the Houben-Weyl style. The wide scope of the volume should certainly encourage synthetic organic chemists to utilize fully the range and versatility of these transition metal-mediated processes. This will certainly be a well-thumbed reference book! R. A. RAPHAEL Cambridge University v Preface In recent years an enormous amount of work has been done on the catalysis of organic reactions by various transition metal species and on the organic reactivity of organo-transition-metal compounds.
Download or read book Transition Metal catalyzed Intramolecular 4 2 Cycloadditions written by Thomas Everett Smith and published by . This book was released on 1996 with total page 776 pages. Available in PDF, EPUB and Kindle. Book excerpt:
