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:
Download or read book Rhodium catalyzed 5 1 and 5 2 Cycloadditions Using 1 4 enyne as the Five carbon Component written by Wangze Song and published by . This book was released on 2016 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Transition metal-catalyzed cycloaddition reaction is one of the most efficient ways to access ring systems and remains to be one of the most active areas in organic chemistry. The discovery of 3-acyloxy-1,4-enyne (ACE) and 3-hydroxy-1,4-enyne (HYE) as the five-carbon components has led to the development of various Rh-catalyzed [5+1] and [5+2] cycloadditions in our group. These novel methods offered efficient access to highly substituted six- and seven-membered carbocycles. I will present our progresses on the development, application and mechanistic studies of the following four [5+1] and [5+2] cycloadditions. 1) Using ACE bearing an electron-rich ester as the five-carbon component, a [5+1] cycloaddition was realized under mild conditions for the preparation of highly substituted phenols. 2) Based on our previous success on Rh-catalyzed intermolecular [5+2] cycloaddition of ACE and alkynes, a library of highly substituted tropones was successfully prepared by modifying the cycloheptatriene products derived from the [5+2] cycloaddition. 3) The scope of the Rh-catalyzed intramolecular [5+2] cycloaddition of ACE with alkenes was expanded and the Rh-catalyzed intramolecular [5+2] cycloaddition of ACE with allenes was developed for the synthesis of highly functionalized bicyclic 5-7 fused ring systems with multiple stereogenic centers. 4) Using HYE as the 5-carbon component, a [5+1] carbonylative benzannulation reaction was previously developed in our group for the synthesis of tricyclic carbazoles. The scope of this tandem reaction is now expanded to the synthesis of tetra- and even pentacyclic ring systems including furocarbazoles, thiophenocarbazole, pyrrolocarbazole, and indolocarbazole. Metal carbene intermediates are involved in most of these cycloadditions. The strategy of using propargylic esters and propargylic alcohols as the Rh(I) carbene precursor should have broad implications in transition metal catalysis and metal carbene chemistry.
Download or read book The Design and Development of New Transition Metal catalyzed Serial and Multi component Cycloadditions written by Gabriel Grant Gamber and published by . This book was released on 2004 with total page 520 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Transition Metal Catalyzed Carbene Transformations written by Jianbo Wang and published by John Wiley & Sons. This book was released on 2021-12-20 with total page 450 pages. Available in PDF, EPUB and Kindle. Book excerpt: Presents an up-to-date overview of the rapidly growing field of carbene transformations Carbene transformations have had an enormous impact on catalysis and organometallic chemistry. With the growth of transition metal-catalyzed carbene transformations in recent decades, carbene transformations are today an important compound class in organic synthesis as well as in the pharmaceutical and agrochemical industries. Edited by leading experts in the field, Transition Metal-Catalyzed Carbene Transformations is a thorough summary of the most recent advances in the rapidly expanding research area. This authoritative volume covers different reaction types such as ring forming reactions and rearrangement reactions, details their conditions and properties, and provides readers with accurate information on a wide range of carbene reactions. Twelve in-depth chapters address topics including carbene C-H bond insertion in alkane functionalization, the application of engineered enzymes in asymmetric carbene transfer, progress in transition-metal-catalyzed cross-coupling using carbene precursors, and more. Throughout the text, the authors highlight novel catalytic systems, transformations, and applications of transition-metal-catalyzed carbene transfer. Highlights the dynamic nature of the field of transition-metal-catalyzed carbene transformations Summarizes the catalytic radical approach for selective carbene cyclopropanation, high enantioselectivity in X-H insertions, and bio-inspired carbene transformations Introduces chiral N,N'-dioxide and chiral guanidine-based catalysts and different transformations with gold catalysis Discusses approaches in cycloaddition reactions with metal carbenes and polymerization with carbene transformations Outlines multicomponent reactions through gem-difunctionalization and transition-metal-catalyzed cross-coupling using carbene precursors Transition Metal-Catalyzed Carbene Transformations is essential reading for all chemists involved in organometallics, including organic and inorganic chemists, catalytic chemists, and chemists working in industry.
Download or read book The Mechanism and Origins of Reactivities and Selectivities in Transition metal catalyzed and Organocatalyzed Cycloadditions written by Xin Hong and published by . This book was released on 2014 with total page 175 pages. Available in PDF, EPUB and Kindle. Book excerpt: A preeminent goal of organic synthesis is to achieve structural complexity with functional value in a step, atom, and time economical fashion. Cycloadditions, as exemplified by the Diels-Alder reaction, represent uniquely powerful processes to achieve this goal. Most of widely-used cycloadditions require transition metal or organic catalysts to achieve the desired control of reactivity and selectivity, which rely on mechanistic understandings at the molecular level. Modern density functional theory (DFT) calculations provide the foundation to achieve such level of understanding, and my PhD research focuses on studying the mechanism and selectivities of a series of important transition-metal-catalyzed and organocatalytic cycloadditions through DFT calculations. The first part of the thesis includes my studies on the mechanism and selectivities of transition-metal-catalyzed cycloadditions. Chapter 1 focuses on the mechanism and origins of selectivities in Ru(II)-catalyzed intramolecular (5+2) cycloadditions and ene reactions of vinylcyclopropanes and alkynes. The favored mechanism involves an initial ene-yne oxidative cyclization to form a ruthenacyclopentene intermediate, which is different from that found earlier with rhodium catalysts. Based on this new mechanism, solvent effect, chemoselectivity, diastereoselectivity and regioselectivity are explained. Chapter 2 includes the study of mechanism and ligand-controlled selectivities in [Ni(NHC)]-catalyzed intramolecular (5+2) cycloadditions and homo-ene reactions of vinylcyclopropanes and alkynes. The reaction mechanism of nickel catalysts is similar to that of ruthenium catalysts, which involves the alkyne-alkene cyclization to form a metallacyclopentene intermediate. The selectivity between the (5+2) and homo-ene products is determined in the subsequent competing reductive elimination and & beta;-hydride elimination steps. The anisotropic steric environments of SIPr and ItBu ligands are the major reasons for the reversed selectivity of these two similar-sized ligands. Chapter 3 emphasizes the study of terminal methyl effects in Rh(I)-catalyzed intermolecular (5+2) cycloadditions of vinylcyclopropanes and allenes. A competitive allene dimerization is found to irreversibly sequester the rhodium catalyst. This explains the necessity of methyl substituents on the reacting double bond of allenes to achieve the desired cycloadditions. The second part of the thesis focuses on my studies of the organocatalyzed cycloadditions. Chapter 4 illustrates the explorations of the mechanism and controlling factors of the organocatalyzed carbonyl-olefin metathesis. In the (3+2) cycloadditions between hydrazonium and alkenes, the distortion of reactants controls the reactivities. In the subsequent cycloreversions, the strain-release of the five-membered ring intermediates determines the reaction barriers. For these two reasons, the cyclopropene derivatives are found to be the most reactive in experiments. Chapter 5 discusses the distortion-acceleration effect of alkynyl substituents in the stepwise hexadehydro-Diels-Aleder (HDDA) Reaction. The HDDA reaction follows a stepwise mechanism with a diradical intermediate. The alkynyl substituent dramatically accelerates the HDDA reaction mainly by decreasing the distortion energy required to achieve the diradical transition state. Chapter 6 focuses on the mechanism and selectivity of N-triflylphosphoramide catalyzed (3+2) cycloaddition between hydrazones and alkenes. The protonation of hydrazones by Brønsted acid catalysts are found to be crucial for the facile (3+2) cycloaddition. This explains the acidity-dependent catalytic activities of this reaction. Based on the mechanism, we have also explained the origins of enantioselectivities when a chiral N-triflylphosphoramide catalyst is employed. Chapter 7 includes the study of mechanism and origins of switchable chemoselectivity of Ni-catalyzed C(aryl)-O and C(acyl)-O activation of aryl esters with phosphine ligands. For aryl esters, nickel with bidentate phosphine ligands cleaves C(acyl)-O and C(aryl)-O bonds via three-centered transition states, and this cleavage favors the weak C(acyl)-O bond. However, when monodentate phosphine ligands are used, the five-centered C(aryl)-O cleavage transition state makes C(aryl)-O activation favorable. In the case of aryl pivalates, nickel with bidentate phosphine ligands still favors the C(acyl)-O activation, but the subsequent decarbonylation requires very high barrier and the alternative C(aryl)-O activation occurs.
Download or read book C C Bond Activation written by Guangbin Dong and published by Springer. This book was released on 2014-09-18 with total page 265 pages. Available in PDF, EPUB and Kindle. Book excerpt: The series Topics in Current Chemistry presents critical reviews of the present and future trends in modern chemical research. The scope of coverage is all areas of chemical science including the interfaces with related disciplines such as biology, medicine and materials science. The goal of each thematic volume is to give the non-specialist reader, whether in academia or industry, a comprehensive insight into an area where new research is emerging which is of interest to a larger scientific audience. Each review within the volume critically surveys one aspect of that topic and places it within the context of the volume as a whole. The most significant developments of the last 5 to 10 years are presented using selected examples to illustrate the principles discussed. The coverage is not intended to be an exhaustive summary of the field or include large quantities of data, but should rather be conceptual, concentrating on the methodological thinking that will allow the non-specialist reader to understand the information presented. Contributions also offer an outlook on potential future developments in the field. Review articles for the individual volumes are invited by the volume editors. Readership: research chemists at universities or in industry, graduate students
Download or read book Design and Development of New Transition Metal catalyzed Two and Three component Cycloaddition Reactions written by Nicole Marie Deschamps and published by . This book was released on 2006 with total page 570 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book I Transition Metal Catalyzed Intramolecular 3 2 Cycloadditions of Methylenecyclopropanes with Electron Deficient Olefins II The Lewis and Protic Acid Rearrangements of Oxaspiropentanes Prepared by the Epoxidation of Methylenecyclopropanes written by Mark A. Nachtigall and published by . This book was released on 1992 with total page 328 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Transition Metal Catalyzed Carbene Transformations written by Jianbo Wang and published by John Wiley & Sons. This book was released on 2022-05-16 with total page 450 pages. Available in PDF, EPUB and Kindle. Book excerpt: Presents an up-to-date overview of the rapidly growing field of carbene transformations Carbene transformations have had an enormous impact on catalysis and organometallic chemistry. With the growth of transition metal-catalyzed carbene transformations in recent decades, carbene transformations are today an important compound class in organic synthesis as well as in the pharmaceutical and agrochemical industries. Edited by leading experts in the field, Transition Metal-Catalyzed Carbene Transformations is a thorough summary of the most recent advances in the rapidly expanding research area. This authoritative volume covers different reaction types such as ring forming reactions and rearrangement reactions, details their conditions and properties, and provides readers with accurate information on a wide range of carbene reactions. Twelve in-depth chapters address topics including carbene C-H bond insertion in alkane functionalization, the application of engineered enzymes in asymmetric carbene transfer, progress in transition-metal-catalyzed cross-coupling using carbene precursors, and more. Throughout the text, the authors highlight novel catalytic systems, transformations, and applications of transition-metal-catalyzed carbene transfer. Highlights the dynamic nature of the field of transition-metal-catalyzed carbene transformations Summarizes the catalytic radical approach for selective carbene cyclopropanation, high enantioselectivity in X-H insertions, and bio-inspired carbene transformations Introduces chiral N,N'-dioxide and chiral guanidine-based catalysts and different transformations with gold catalysis Discusses approaches in cycloaddition reactions with metal carbenes and polymerization with carbene transformations Outlines multicomponent reactions through gem-difunctionalization and transition-metal-catalyzed cross-coupling using carbene precursors Transition Metal-Catalyzed Carbene Transformations is essential reading for all chemists involved in organometallics, including organic and inorganic chemists, catalytic chemists, and chemists working in industry.
Download or read book Transition Metals in the Synthesis of Complex Organic Molecules written by Louis S. Hegedus and published by University Science Books. This book was released on 1999 with total page 358 pages. Available in PDF, EPUB and Kindle. Book excerpt: This second edition offers easy access to the field of organotransition metal chemistry. The book covers the basics of transition metal chemistry, giving a practical introduction to organotransition reaction mechanisms.
Download or read book Studies of Rhodium catalyzed 5 2 Cycloadditions and Their Applications in Organic Synthesis written by Craig Owen Husfeld and published by . This book was released on 2001 with total page 744 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Advances in Organic Synthesis written by Atta-ur-Rahman and published by Bentham Science Publishers. This book was released on 2013-03-27 with total page 513 pages. Available in PDF, EPUB and Kindle. Book excerpt: Advances in Organic Synthesis is a book series devoted to the latest advances in synthetic approaches towards challenging structures. It presents comprehensive articles written by eminent authorities on different synthetic approaches to selected target molecules and new methods developed to achieve specific synthetic transformations. Contributions are written by eminent scientists and each volume is edited by an authority in the field. Advances in Organic Synthesis is essential for all organic chemists in the academia and industry who wish to keep abreast of rapid and important developments in the field.
Download or read book New Methodologies and Techniques for a Sustainable Organic Chemistry written by Alessandro Mordini and published by Springer Science & Business Media. This book was released on 2008-04-17 with total page 339 pages. Available in PDF, EPUB and Kindle. Book excerpt: Chemical industries have to face the challenge of finding adequate processes to produce large quantities of new products, while at the same time decreasing both the impact on the environment and the risk of disaster. This book addresses this challenge. It discusses the problems of environmentally benign organic processes on an interdisciplinary approach. The book features experts in selective catalysis, development of new reagents and methods who present their recent results.
Download or read book Design and Development of Transition Metal catalyzed M N Cycloadditions written by Robert Sun and published by . This book was released on 2003 with total page 1096 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 Transition Metal and Organo catalyzed Cycloreductions Cycloadditions and Cycloisomerizations written by Ana Liza Luis and published by . This book was released on 2005 with total page 542 pages. Available in PDF, EPUB and Kindle. Book excerpt: The catalytic activation of enones in C-C bond forming processes represents a promising alternative to the prefabrication of chemically labile enols and enolates. Through the use of a (diketonato)cobalt/silane catalyst system, we have devised highly diastereoselective aldol and Michael cycloreductions (J. Am. Chem. Soc. 2001, 123, 5112). Modulation of the catalyst system has enabled the first intramolecular metal-catalyzed alkene (2+2)cycloaddition (J. Am. Chem. Soc. 2001, 123, 6716). Finally, the concept of catalytic nucleophilic enone activation embodied by the Morita-Baylis- Hillman and Rauhut Currier reactions has been utilized to develop an organic catalyst system for the cycloisomerization of bis-enones, i.e. an intramolecular Rauhut Currier reaction (J. Am. Chem. Soc. 2002, 124, 2402). Notably, this protocol allowed for the selective "crossed" cyclization of unsymmetrical bis-enone substrates.
Download or read book Cycloaddition Reactions in Organic Synthesis written by Shu Kobayashi and published by John Wiley & Sons. This book was released on 2002 with total page 354 pages. Available in PDF, EPUB and Kindle. Book excerpt: During the miners' strike in the 1980s, a worker is killed in the striking coalfields of Wales. Some months later, a government minister thought to be connected with the death is also shot. Lewis Redfern—once a radical but now a political analyst and journalist—pursues the sniper, a lonely hunt that leads him through an imbroglio of civil service leaks to a secret organization: a source of insurrection far more powerful than anyone could have suspected known as the Volunteers. In this fast-paced narrative of espionage and intrigue, Redfern, through his obsessive pursuit of justice, finally encounters the truth about himself as the novel discusses the conflict between moral choice and political loyalty.
