Download or read book Investigations of the Mechanism of a Friedel Crafts Like Gold and Silver Catalyzed Microwave Reaction written by Tamara Nader El-Hayek Ewing and published by . This book was released on 2021 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Within the last 20-40 years, gold catalysis has becoming increasingly more interesting to researchers. A particular turning point was when one group was able to perform several alcohol additions to unactivated alkynes using a gold(I) catalyst. A significant result of this success was the ability to replace toxic mercury (II) catalysts that had been previously used to perform similar transformations. Since this report, others have successfully shown that gold(I) catalysts of the form [L-Au-Cl] as well as gold(III) catalysts in various forms, are able to activate a variety of starting materials for inter and intramolecular transformations. Despite this work, the mechanism of action for gold catalysis remains unknown. There are several complicating factors including relativistic, ligand, solvent and temperature effects, among others. Of particular interest to us are silver effect complications as well as the phenomena of gold decay. Silver salts are typically used in gold catalysis as an activating co-catalyst. The silver salt is presumed to be a halide scavenger in gold(I) catalysis, removing the chloride and exposing the Au+ center. However, several groups have reported on silver and its counter ion playing a less benign role--even demonstrating that silver can catalyze transformations on its own. This at the least warrants further investigation of the nature of silver in the reaction. Gold decay also introduces complications to gold catalysis. One possibility for the explanation for gold decay is through disproportionation of the gold(I) catalyst to gold(0) and gold(III). This is a particularly exciting avenue for exploration in the work done here. In the reaction of interest, 1-phenylethol and 4-methylanisole combine to produce a Friedel-Crafts-like product. In typical Friedel-Crafts reactions, a hard acid like AlCl3 is used to generate a carbocation which then undergoes a nucleophilic addition and C-C bond formation. In our reaction, if the gold(I) catalyst that was utilized initially were to disproportionate, gold(III)--a harder Lewis Acid--would help explain the Friedel-Crafts reactivity and the gold(0) generated would explain the gold-plating on the vials seen after the reaction. Through organic synthesis methods as well as some inorganic analysis, we were able to make some interesting discoveries. First, we see gold(I) decay in the absence of substrate, visually producing black/purple particles. At extended reaction times, the analysis of these particles shows about 33% of the gold we put in by mass was recovered. This still left open the possibility of gold(I) in solution as the active catalyst, however. In fact, when the particles from the substrate-less reaction were filtered out, the filtrate remaining was still able to catalyze the reaction. This did not lead us closer to understanding if gold(I) or gold(III) was the active catalyst but did let us know that the active catalyst remained in solution despite decay. We were also able to confirm that a gold(III) salt can catalyze the reaction of interest, though the yields were less than half of what was accomplished in the optimized gold(I) reaction. Additionally, with low catalyst loadings and significantly reduced reaction times (1 minute), a secondary product was observed in the gold(III)-catalyzed reactions. The nature of this secondary product--whether it is a major/minor product or if it is some intermediate species is still under investigation. Overall, evidence showing that gold(0) is being formed and the ability for a gold(III) salt to form the Friedel-Crafts-like product is clear, but that alone does not fully support disproportionation. Indirect evidence leads us to believe that disproportionation is the mechanism for gold decay, however, without direct evidence of a gold(III) species, we cannot say for sure. Also, there is some support for gold(III) being the active catalyst but there are some necessary questions that still need to be explored. In particular, an investigation of the possible intermediate or secondary product in both gold(I) and gold(III)-catalyzed reactions would be helpful in identifying the mechanistic path for the C-C bond formation in this Friedel-Crafts-like addition.
Download or read book Asymmetric catalysis written by Michael P. Doyle and published by JAI Press(NY). This book was released on 1997 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is the second volume in a series covering research advances in the field of catalytic processes.
Download or read book Homogeneous Gold Catalysis written by LeGrande M. Slaughter and published by Springer. This book was released on 2015-03-30 with total page 292 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 Synthetic Applications written by Rajender S. Varma and published by Walter de Gruyter GmbH & Co KG. This book was released on 2022-05-09 with total page 578 pages. Available in PDF, EPUB and Kindle. Book excerpt: Magnetic nanocatalysts are becoming an important tool for greener catalytic processes in chemical transformations in view of the ease of their removal from a reaction medium. This book explores assorted magnetic nanocatalysts, their deployment in synthesis, chemical transformation and their recovery and reuse. Various thematic topics embodied include magnetic nanocatalysts for S-S bond formation, N-heterocycle formation, C-heteroatom bond formation, silica-supported catalysts, multicomponent reactions, including their recyclability; another available volume emphasizes the utility of magnetic nanocatalysts in industrial appliances.
Download or read book Artificial Metalloenzymes and MetalloDNAzymes in Catalysis written by Montserrat Diéguez and published by John Wiley & Sons. This book was released on 2018-02-21 with total page 431 pages. Available in PDF, EPUB and Kindle. Book excerpt: An important reference for researchers in the field of metal-enzyme hybrid catalysis Artificial Metalloenzymes and MetalloDNAzymes in Catalysis offers a comprehensive review of the most current strategies, developed over recent decades, for the design, synthesis, and optimization of these hybrid catalysts as well as material about their application. The contributors—noted experts in the field—present information on the preparation, characterization, and optimization of artificial metalloenzymes in a timely and authoritative manner. The authors present a thorough examination of this interesting new platform for catalysis that combines the excellent selective recognition/binding properties of enzymes with transition metal catalysts. The text includes information on the various applications of metal-enzyme hybrid catalysts for novel reactions, offers insights into the latest advances in the field, and contains an informative perspective on the future: Explores the development of artificial metalloenzymes, the modern and strongly evolving research field on the verge of industrial application Contains a comprehensive reference to the research area of metal-enzyme hybrid catalysis that has experienced tremendous growth in recent years Includes contributions from leading researchers in the field Shows how this new catalysis combines the selective recognition/binding properties of enzymes with transition metal catalysts Written for catalytic chemists, bioinorganic chemists, biochemists, and organic chemists, Artificial Metalloenzymes and MetalloDNAzymes in Catalysis offers a unique reference to the fundamentals, concepts, applications, and the most recent developments for more efficient and sustainable synthesis.
Download or read book Index to Theses with Abstracts Accepted for Higher Degrees by the Universities of Great Britain and Ireland and the Council for National Academic Awards written by and published by . This book was released on 2007 with total page 694 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Gold Catalysis An Homogeneous Approach written by Veronique Michelet and published by World Scientific. This book was released on 2014-06-20 with total page 564 pages. Available in PDF, EPUB and Kindle. Book excerpt: Research on designing new catalytic systems has been one of the most important fields in modern organic chemistry. One reason for this is the predominant contribution of catalysis to the concepts of atom economy and green chemistry in the 21st century. Gold, considered catalytically inactive for a long time, is now a fascinating partner of modern chemistry, as scientists such as Bond, Teles, Haruta, Hutchings, Ito and Hayashi opened new perspectives for the whole synthetic chemist community. This book presents the major advances in homogeneous catalysis, emphasizing the methodologies that create carbon-carbon and carbon-heteroatom bonds, the applications that create diversity and synthesize natural products, and the recent advances and challenges in asymmetric catalysis and computational research.It provides readers with in-depth information about homogeneous gold-catalyzed reactions and presents several explanations for the scientific design of a catalyst. Readers will be able to understand the entire gold area and find solutions to problems in catalysis.Gold Catalysis — An Homogeneous Approach is part of the Catalytic Science Series and features prominent authors who are experts in their respective fields.
Download or read book March s Advanced Organic Chemistry written by Michael B. Smith and published by John Wiley & Sons. This book was released on 2007-01-29 with total page 2379 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Sixth Edition of a classic in organic chemistry continues its tradition of excellence Now in its sixth edition, March's Advanced Organic Chemistry remains the gold standard in organic chemistry. Throughout its six editions, students and chemists from around the world have relied on it as an essential resource for planning and executing synthetic reactions. The Sixth Edition brings the text completely current with the most recent organic reactions. In addition, the references have been updated to enable readers to find the latest primary and review literature with ease. New features include: More than 25,000 references to the literature to facilitate further research Revised mechanisms, where required, that explain concepts in clear modern terms Revisions and updates to each chapter to bring them all fully up to date with the latest reactions and discoveries A revised Appendix B to facilitate correlating chapter sections with synthetic transformations
Download or read book Iron Catalysis written by Bernd Plietker and published by Springer Science & Business Media. This book was released on 2011-01-05 with total page 227 pages. Available in PDF, EPUB and Kindle. Book excerpt: Juan I. Padrón and Víctor S. Martín: Catalysis by means of Fe-based Lewis acids; Hiroshi Nakazawa*, Masumi Itazaki: Fe–H Complexes in Catalysis; Kristin Schröder, Kathrin Junge, Bianca Bitterlich, and Matthias Beller: Fe-catalyzed Oxidation Reactions of Olefins, Alkanes and Alcohols: Involvement of Oxo- and Peroxo Complexes; Chi-Ming Che, Cong-Ying Zhou, Ella Lai-Ming Wong: Catalysis by Fe=X Complexes (X=NR, CR2); René Peters, Daniel F. Fischer and Sascha Jautze: Ferrocene and Half Sandwich Complexes as Catalysts with Iron Participation; Markus Jegelka, Bernd Plietker: Catalysis by Means of Complex Ferrates.
Download or read book Hydrogen Transfer Reactions written by Gabriela Guillena and published by Springer. This book was released on 2016-09-27 with total page 393 pages. Available in PDF, EPUB and Kindle. Book excerpt: The series Topics in Current Chemistry Collections presents critical reviews from the journal Topics in Current Chemistry organized in topical volumes. 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.
Download or read book Iron Catalysis in Organic Chemistry written by Bernd Plietker and published by John Wiley & Sons. This book was released on 2008-09-08 with total page 295 pages. Available in PDF, EPUB and Kindle. Book excerpt: This first comprehensive book to cover this exciting field also deals with the biological aspects, such as enzymes with iron. Following an introduction, this handy reference and handbook goes on to deal with reductions, oxidations of C, H- and C=C bonds, oxidative allylic oxygenation and amination, the oxidation of heteroatoms, cross coupling reactions, aromatic and nucleophilic substitutions, addition to carbonyl compounds, and cyclisations as well as ring opening reactions. The chapters are clearly classified according to the reaction type, allowing readers to quickly locate the desired information.
Download or read book U S Government Research and Development Reports Index written by and published by . This book was released on 1970 with total page 1332 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Modular Chemistry written by Josef Michl and published by Springer. This book was released on 2012-11-06 with total page 677 pages. Available in PDF, EPUB and Kindle. Book excerpt: Modular Chemistry: the First Steps In recent years, there has been increasing interest among chemists, physicists, materials scientists, biologists, engineers, and others in the assembly of well defmed, relatively large functional structures from repetitive units that themselves are molecules of some complexity. Using the dictionary defmition of a module (a detachable section, compartment, or unit with a specific purpose or function, and in electronics, a compact assembly functioning as a component of a larger unit) [1], we feel that this newly emerging field of endeavor could be called "modular chemistry" [2]. The NATO Advanced Research Workshop on Modular Chemistry that was held on September 9 to 12, 1995, at Aspen Lodge near Estes Park, Colorado, was meant to bring together prominent contributors to modular chemistry as it is being born, and to examine the associated birth pangs. It was concluded that although real, these are not nearly as bad as giving birth to a hedgehog tail first, and that the ultimate rewards were likely to be far more satisfying in terms of new ideas and enabling methodology. The level of excitement about the possibilities that are opening up for modular chemists, and also the challenge involved, are perhaps best documented by noting that the planned discussion periods at the workshop were as long as the oral presentation periods, and yet, each discussion ran over the allocated time.
Download or read book Organic Synthesis written by Belakatte Parameshwarappa Nandeshwarappa and published by BoD – Books on Demand. This book was released on 2020-05-27 with total page 250 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book ‘Organic Synthesis - A Nascent Relook’ is a compendium of the recent progress in all aspects of organic chemistry including bioorganic chemistry, organo-metallic chemistry, asymmetric synthesis, heterocyclic chemistry, natural product chemistry, catalytic, green chemistry and medicinal chemistry, polymer chemistry, as well as analytical methods in organic chemistry. The book presents the latest developments in these fields. The chapters are written by chosen experts who are internationally known for their eminent research contributions. Organic synthesis is the complete chemical synthesis of a target molecule. In this book, special emphasis is given to the synthesis of various bioactive heterocycles. Careful selection of various topics in this book will serve the rightful purpose for the chemistry community and the industrial houses at all levels.
Download or read book Total Synthesis of Natural Products written by Jie Jack Li and published by Springer Science & Business Media. This book was released on 2013-03-14 with total page 292 pages. Available in PDF, EPUB and Kindle. Book excerpt: 'Total Synthesis of Natural Products' is written and edited by some of today's leaders in organic chemistry. Eleven chapters cover a range of natural products, from steroids to alkaloids. Each chapter contains an introduction to the natural product in question, descriptions of its biological and pharmacological properties and outlines of total synthesis procedures already carried out. Particular emphasis is placed on novel methodologies developed by the respective authors and their research groups. This text is ideal for graduate and advanced undergraduate students, as well as organic chemists in academia and industry.
Download or read book Silver in Organic Chemistry written by Michael Harmata and published by John Wiley & Sons. This book was released on 2011-01-11 with total page 395 pages. Available in PDF, EPUB and Kindle. Book excerpt: The first authoritative book on using silver cations in organic chemistry—for catalysis and more! With more sophisticated catalytic methodologies fueling a resurgence in the study of cation-based chemistry, gold and platinum have stepped to the fore as the unique agents used to create new chemical reactions. Although these metals have become a primary focus of researchers in the field, another coinage metal that is often overlooked—but is as powerful as the others—is silver, a far less costly alternative to gold and platinum in aiding the development of new reactions. Making a strong case for the use of silver as a catalyst and structural element in organometal constructs, this authoritative book is the first to explore the benefits of using silver in organic chemistry by taking a close look at silver’s unique reactivity and structural characteristics for the development of new methods and materials. Silver in Organic Chemistry is: The first book to address catalysis using silver, whose use in organic chemistry is on the verge of exploding A resource for researchers wishing to do chemistry with silver cations, an area that stands in the shadow of gold chemistry, but still glistens, demonstrating that all that glitters is not gold—sometimes it’s silver! A guide for “first attempts” in working with silver cations Edited by a very well-respected, highly visible authority in this field Silver in Organic Chemistry promotes further scientific discussion by offering important new ways to examine the future possibilities of an emerging field. By elevating the importance of silver chemistry, this thought-provoking guide illustrates how this versatile metal can become an increasingly significant player in opening the door to new catalytic organic reactions and new organometal materials.
Download or read book Surface Chemistry and Catalysis written by Albert F. Carley and published by Springer Science & Business Media. This book was released on 2002-09-30 with total page 404 pages. Available in PDF, EPUB and Kindle. Book excerpt: Exciting results are still emerging from the many research groups working in this fertile area and the book is an excellent stimulus to researchers at the start of the 21st century."--BOOK JACKET.
