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 956 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 Rhodium catalyzed Cycloadditions and Cycloisomerizations Involving Propargylic Esters and Alcohols written by Xiaoxun Li and published by . This book was released on 2014 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Transition metal-catalyzed cyloaddition and cycloisomerization reactions occupy a central position within the realm of organic synthesis. Research described in this thesis focuses on using propargylic esters and alcohols as building blocks for rhodium(I)-catalyzed cycloadditions and cycloisomerizations. The discovery and application of combining the [pi]-acidity and redox/insertion reactivity of rhodium(I) complexes, led to the development of many new reactions. By taking advantage of Rh-catalyzed 1,3-acyloxy migration of propargylic esters, I developed two tandem reactions. One is Rh-catalyzed carbonylation of 3-acyloxy-1,4-enynes (ACEs) for the synthesis of highly substituted cyclopentenones, and the other is ring expansion of cyclopropanes or cyclobutanes for the preparation of highly functionalized seven-membered or eight-membered carbocycles. By taking advantage of Rh-catalyzed 1,2-acyloxy migration of propargylic esters adjacent to heterocycles, I developed a novel and practical method for the preparation of a series of heterocycles including indoles, benzofurans, carbazoles and benzothiophenes from substituted pyrroles, furans, indoles and thiophenes. Inspired by the first Rh-catalyzed intra- and intermolecular [5+2] cycloadditions of 3-acyloxy-1,4-enynes (ACEs) with alkynes, I developed a new five-carbon building block, an inverted ACE, for [5+2] cycloadditions by switching the position of the alkene and alkyne groups in ACE. By replacing the acyloxy group in ACE with OH leaving group and aniline nucleophile, a completely new type of 5-carbon building block (HYE) was designed for cycloadditions. The tandem indole annulation and [5+1] cycloaddition was realized for the synthesis of various highly substituted carbazoles. Natural products glycosinine and mahanimbine were prepared. Furthermore, indolyl Rh(I)-carbene could be generated from 3-hydroxy-1,4-enyne (HYE) through a dehydration process. With different N-protecting group, I prepared dimeric indoles, cyclopropyl indoles, vinyl indoles and other interesting indole derivatives.
Download or read book Computational Methods in Organometallic Catalysis written by Yu Lan and published by John Wiley & Sons. This book was released on 2021-03-24 with total page 672 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book includes a historical introduction to organometallic chemistry, a survey of mechanisms, and an extensive introduction to quantum mechanical computational methods.
Download or read book Modern Rhodium Catalyzed Organic Reactions written by P. Andrew Evans and published by John Wiley & Sons. This book was released on 2006-03-06 with total page 496 pages. Available in PDF, EPUB and Kindle. Book excerpt: Rhodium has proven to be an extremely useful metal due to its ability to catalyze an array of synthetic transformations, with quite often-unique selectivity. Hydrogenation, C-H activation, allylic substitution, and numerous other reactions are catalyzed by this metal, which presumably accounts for the dramatic increase in the number of articles that have recently emerged on the topic. P. Andrew Evans, the editor of this much-needed book, has assembled an internationally renowned team to present the first comprehensive coverage of this important area. The book features contributions from leaders in the field of rhodium-catalyzed reactions, and thereby provides a detailed account of the most current developments, including: Rhodium-Catalyzed Asymmetric Hydrogenation (Zhang) Rhodium-Catalyzed Hydroborations and Related Reactions (Brown) Rhodium-Catalyzed Asymmetric Addition of Organometallic Reagents to Electron Deficient Olefins (Hayashi) Recent Advances in Rhodium(I)-Catalyzed Asymmetric Olefin Isomerization and Hydroacylation Reactions (Fu) Stereoselective Rhodium(I)-Catalyzed Hydroformylation and Silylformylation Reactions and Their Application to Organic Synthesis (Leighton) Carbon-Carbon Bond-Forming Reactions Starting from Rh-H or Rh-Si Species (Matsuda) Rhodium(I)-Catalyzed Cycloisomerization and Cyclotrimerization Reactions (Ojima) The Rhodium(I)-Catalyzed Alder-ene Reaction (Brummond) Rhodium-Catalyzed Nucleophilic Ring Cleaving Reactions of Allylic Ethers and Amines (Fagnou) Rhodium(I)-Catalyzed Allylic Substitution Reactions and their Applications to Target Directed Synthesis (Evans) Rhodium(I)-Catalyzed [2+2+1] and [4+1] Carbocyclization Reactions (Jeong) Rhodium(I)-Catalyzed [4+2] and [4+2+2] Carbocyclizations (Robinson) Rhodium(I)-Catalyzed [5+2], [6+2], and [5+2+1] Cycloadditions: New Reactions for Organic Synthesis (Wender) Rhodium(II)-Stabilized Carbenoids Containing both Donor and Acceptor Substituents (Davies) Chiral Dirhodium(II)Carboxamidates for Asymmetric Cyclopropanation and Carbon-Hydrogen Insertion Reactions (Doyle) Cyclopentane Construction by Rhodium(II)-Mediated Intramolecular C-H Insertion (Taber) Rhodium(II)-Catalyzed Oxidative Amination (DuBois) Rearrangement Processes of Oxonium and Ammonium Ylides Formed by Rhodium(II)-Catalyzed Carbene-Transfer (West) Rhodium(II)-Catalyzed 1,3-Dipolar Cycloaddition Reactions (Austin) "Modern Rhodium-Catalyzed Organic Reactions" is an essential reference text for researchers at all levels in the general area of organic chemistry. This book provides an invaluable overview of the most significant developments in this important area of research, and will no doubt be an essential text for researchers at academic institutions and professionals at pharmaceutical/agrochemical companies.
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 The Design and Development of a New Reaction Rhodium catalyzed 5 2 Cycloadditions written by Jennifer Ann Love and published by . This book was released on 2000 with total page 624 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Studies on Rhodium Catalyzed 5 2 Cocyclization Reactions written by Hermann Wegner and published by Cuvillier Verlag. This book was released on 2004 with total page 206 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 Catalyst Components for Coupling Reactions written by Gary A. Molander and published by John Wiley & Sons. This book was released on 1999 with total page 694 pages. Available in PDF, EPUB and Kindle. Book excerpt: ""While a number of books and review articles describe the importance and application of different aspects of coupling reactions, this Handbook will be a compilation of all major catalyst components in use in the area, and is intended to guide the experimentalist and facilitate choice among the numerous reagents available for any one purpose."" (Live-PR (EN), 16 March 2011)
Download or read book Studies on Rhodium Catalyzed 5 2 Cocyclization Rections written by and published by Cuvillier Verlag. This book was released on 2004-09-20 with total page 140 pages. Available in PDF, EPUB and Kindle. Book excerpt: The first part of this thesis dealt with the a new kind of precursors for transition metalcatalyzed cocyclization reactions containing a vinylbicyclopropyl unit, their synthesis and their behavior in cocyclization reactions. By introducing a second cyclopropane the catalyst might open this ring as well after insertion into the first cyclopropane ring. The ’basic’ formal [5+2] cycloaddition reaction would be extended to a [5+2+3] cocyclization reaction to form ten-membered rings. In addition to the importance as a new synthetic tool valuable insights into the mechanism of transition metal-catalyzed cocyclization reactions of vinylcyclopropanes are gained.
Download or read book Rhodium Catalysis in Organic Synthesis written by Ken Tanaka and published by John Wiley & Sons. This book was released on 2018-12-31 with total page 254 pages. Available in PDF, EPUB and Kindle. Book excerpt: An essential reference to the highly effective reactions applied to modern organic synthesis Rhodium complexes are one of the most important transition metals for organic synthesis due to their ability to catalyze a variety of useful transformations. Rhodium Catalysis in Organic Synthesis explores the most recent progress and new developments in the field of catalytic cyclization reactions using rhodium(I) complexes and catalytic carbon-hydrogen bond activation reactions using rhodium(II) and rhodium(III) complexes. Edited by a noted expert in the field with contributions from a panel of leading international scientists, Rhodium Catalysis in Organic Synthesis presents the essential information in one comprehensive volume. Designed to be an accessible resource, the book is arranged by different reaction types. All the chapters provide insight into each transformation and include information on the history, selectivity, scope, mechanism, and application. In addition, the chapters offer a summary and outlook of each transformation. This important resource: -Offers a comprehensive review of how rhodium complexes catalyze a variety of highly useful reactions for organic synthesis (e.g. coupling reactions, CH-bond functionalization, hydroformylation, cyclization reactions and others) -Includes information on the most recent developments that contain a range of new, efficient, elegant, reliable and useful reactions -Presents a volume edited by one of the international leading scientists working in the field today -Contains the information that can be applied by researchers in academia and also professionals in pharmaceutical, agrochemical and fine chemical companies Written for academics and synthetic chemists working with organometallics, Rhodium Catalysis in Organic Synthesis contains the most recent information available on the developments and applications in the field of catalytic cyclization reactions using rhodium complexes.
Download or read book Rhodium bisphosphine Monooxide catalyzed 4 2 2 Cycloaddition Reactions for the Synthesis of Fused Polycyclic Systems written by Gino Martin R. Canlas and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The synthesis of polycyclic systems, especially those that with an eight-membered ring embedded into the structure, has long been pursued due to their ubiquitousness in numerous natural product motifs. These eight-membered rings may be efficiently synthesized using metal-catalyzed higher order cycloadditions. In our studies, some cationic rhodium(I) complexes were found to catalyze a previously-discovered [4+2+2] cycloaddition between dienynes and external alkynes giving fused systems with a cycloocta-1,3,5-triene core. Upon screening of various metal complexes, ligands and solvents, a catalytically-competent, novel rhodium-BozPHOS complex, [Rh(nbd){(S,S)-Me-BozPHOS}]SbF6, was obtained using one equivalent of [Rh(nbd)Cl]2, two equivalents of the ligand (S,S)-Me-BozPHOS and two equivalents of AgSbF6. Using this complex in the [4+2+2] cycloaddition reaction provided bicyclic systems in moderate to good yields from two molecules of acyclic dienyne or a molecule of acyclic dienyne and external alkyne. Furthermore, this complex allowed the expansion of the substrate scope for this catalytic reaction involving cyclic dienynes. It was found that only dienynes with an embedded five-membered ring provided the tricyclic system in good yields. This novel rhodium complex was also applied to the [4+2+2] cycloaddition approach towards the synthesis of (±)-asteriscanolide, leading to the formation of the asteriscane skeleton. Despite this success, various selective hydrogenation and oxidation methods failed to functionalize the cyclooctatriene system due to the electronic and steric similarities of the three double bonds in the ring, thus, preventing access to the natural produc
Download or read book Rhodium Catalyzed Hydroformylation written by Piet W.N.M. van Leeuwen and published by Springer. This book was released on 2000-09-30 with total page 286 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the last decade there have been numerous advances in the area of rhodium-catalyzed hydroformylation, such as highly selective catalysts of industrial importance, new insights into mechanisms of the reaction, very selective asymmetric catalysts, in situ characterization and application to organic synthesis. The views on hydroformylation which still prevail in the current textbooks have become obsolete in several respects. Therefore, it was felt timely to collect these advances in a book. The book contains a series of chapters discussing several rhodium systems arranged according to ligand type, including asymmetric ligands, a chapter on applications in organic chemistry, a chapter on modern processes and separations, and a chapter on catalyst preparation and laboratory techniques. This book concentrates on highlights, rather than a concise review mentioning all articles in just one line. The book aims at an audience of advanced students, experts in the field, and scientists from related fields. The didactic approach also makes it useful as a guide for an advanced course.
Download or read book Investigations of 5 2 and Other Cycloadditions written by Lauren Elizabeth Sirois and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Those who study new reactions and their selectivities are often driven by an interest in developing novel, practical methods that can be exploited to achieve complex chemical transformations over a small number of synthetic steps. The ultimate goal of such efforts is to achieve step economy, an overarching principle of green chemistry that minimizes reagents, waste, and production time. The design and application of metal-catalyzed and light-mediated cycloadditions is one important avenue of research, as such transformations can be atom economical and, more importantly, can create multiple bonds, rings, and stereocenters in a single step toward targets of high complexity and value. Linked to the development of new reactions is the design and understanding of new catalysts and ligands possessing novel reactivities and selectivities. Step economy can also be achieved by the clever streamlining of multiple transformations into a single synthetic operation, thus further reducing material and personnel costs. Such single-flask serial/cascade reactions can be used for the rapid assembly of molecular scaffolds, some of which comprise the core of targets with exciting physical properties or biological activity. The research presented in this dissertation addresses all of these themes. Within the context of similar reactions of activated, strained rings, Chapter 1 introduces the metal-catalyzed [5+2] cycloaddition of vinylcyclopropanes (VCPs) and pi-systems for the construction of seven-membered rings, an important motif in many natural products and natural-product-inspired synthetic targets. Chapter 2 describes the latest advancements in new catalysts and new ligands for the strategically convergent and operationally simple rhodium(I)-catalyzed intermolecular [5+2] reactions of VCPs and alkyne feedstocks. In Chapter 3, the regioselectivity of intermolecular [5+2] cycloadditions is explored systematically, as unsymmetrical substrates can give rise to multiple regioisomeric cycloadducts depending upon the orientation of the alkyne during a postulated (turnover-limiting) migratory insertion mechanistic step. Chapters 4 and 5 illustrate the development and application of single-flask / serial reactions involving the [5+2] cycloaddition, making use of the catalysts and insights from Chapters 2 and 3. In Chapter 4, an intermolecular [5+2] cycloaddition of enynones and VCPs, followed by a Nazarov cyclization, is envisioned for strategically novel and rapid access to the bicyclo[5.3.0]decane skeleton from readily available components. Chapter 5 describes the evolution of a project that, guided by the principles of function-oriented synthesis to access the minimally necessary chemical space for function via the fewest synthetic steps, uses serial [5+2]/[4+2] cycloadditions to assemble novel, potent inhibitors of protein kinase C (PKC). Lastly, Chapter 6 describes a total synthesis of penifulvin A, a sesquiterpenoid metabolite reported as the first example of a naturally occurring dioxa[5,5,5,6]fenestrane. The synthetic strategy features the use of an arene-alkene meta photocycloaddition as the key complexity-generating reaction.
Download or read book Metals and Non metals written by Navjeet Kaur and published by CRC Press. This book was released on 2020-01-28 with total page 404 pages. Available in PDF, EPUB and Kindle. Book excerpt: Design of new processes that avoid the use of toxic reagents has been the focus of intense research of late. Catalysis by metals and non-metals offers diverse opportunities for the development of new organic reactions with promising range of selectivities—chemoselectivity, regioselectivity, diastereoselectivity, and enantioselectivity. Furthermore, these transformations frequently occur under mild conditions, tolerate a broad array of functional groups, and proceed with high stereoselectivity. The area of catalysis is sometimes referred to as a ‘foundational pillar’ of green chemistry. Catalytic reactions often reduce energy requirements and decrease separations because of increased selectivity; they are also capable of permitting the use of renewable feedstocks of less toxic reagents or minimizing the quantities of reagents needed. New catalytic organic synthesis methodologies have, thus, offered several possibilities for considerable improvement in the eco-compatibility of fine chemical production. Hence, these catalytic methodologies have emerged as powerful tools for the efficient and chemoselective synthesis of heterocyclic molecules. Key Features: Presents the synthesis of different five-membered heterocycles. Contains the most up-to-date information in this fast-moving field. Covers novel catalytic approaches used in the study and application of catalysts in synthetic organic reactions. Presents new methodologies for the synthesis of heterocycles.
Download or read book Rhodium and Platinum Catalyzed Cycloadditions from Propargylic Esters and Ethers written by and published by . This book was released on 2013 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The past decade has witnessed a "gold rush" due to the novel [tau tau]-acidity of gold. On the other hand, rhodium is well known for traditional organometallic reactivities such as oxidative addition, reductive elimination, and carbonylation, which makes rhodium widely utilized in industrial processes such as hydroformylation and Monsanto acetic acid synthesis. My Ph.D. research combines [tau tau]-acidity of rhodium with traditional reactivities of rhodium. In particular, we use [tau tau]-acidic Rh-complexes to activate propargylic esters and ethers for cycloadditions. Propargylic esters can undergo either 1,3- or 1,2-acyloxy migration in the presence of rhodium to form allenes and vinyl metal carbenes respectively. By taking advantage of the Rh-catalyzed 1,3-acyloxy migration, I developed a [5+1] cycloaddition starting from cyclopropyl propargylic esters. By taking advantage of Rh-catalyzed 1,2-acyloxy migration, I contributed to the synthesis of 7- and 8-membered rings starting from vinyl propargylic esters. Vinyl metal carbenes could also be obtained from propargylic esters tethered with a nucleophile. By employing either platinum or rhodium metal complexes, I developed a tandem indole annulation and [4+3] cycloaddition with dienes and furans involving vinyl metal carbene intermediates. Biologically interesting bisindoles were also synthesized through a similar indole annulation followed by intermolecular nucleophilic trap of external indoles.
Download or read book Carbon Monoxide in Organic Synthesis written by Bartolo Gabriele and published by John Wiley & Sons. This book was released on 2021-09-30 with total page 432 pages. Available in PDF, EPUB and Kindle. Book excerpt: Carbon Monoxide in Organic Synthesis A thoroughly up-to-date overview of carbonylation reactions in the presence of carbon monoxide In Carbon Monoxide in Organic Synthesis: Carbonylation Chemistry, expert researcher and chemist Bartolo Gabriele delivers a robust summary of the most central advances in the field of carbonylation reactions in the presence of carbon monoxide. Beginning with a brief introduction on the importance of carbon monoxide as a building block in modern organic synthesis, the author goes on to describe metal-catalyzed carbonylations utilizing iron, cobalt, nickel, copper, and manganese. Descriptions of palladium, ruthenium, and rhodium-catalyzed reactions follow, as do discussions of metal-free carbonylation processes. The book is organized by metal to make the book useful as a guide for researchers from both academia and industry whose work touches on the direct synthesis of carbonyl compounds, carboxylic acid derivatives, and heterocycles. It aims to stimulate further discoveries in this rapidly developing field. Readers will also enjoy: A thorough introduction to carbonylations promoted by first row transition metal catalysts, including cobalt-catalyzed and nickel-catalyzed carbonylations An exploration of carbonylations promoted by second row transition metal catalysts, including ruthenium-, rhodium-, palladium(0)-, and palladium (II)-catalyzed carbonylations Practical discussions of miscellaneous carbonylation reactions, including carbonylations promoted by third row transition metal catalysts and metal-free carbonylation processes Perfect for catalytic and organic chemists, Carbon Monoxide in Organic Synthesis: Carbonylation Chemistry is also an indispensable resource for chemists working with organometallics and industrial chemists seeking a summary of important processes used to synthesize value-added products.
