Radical and Ion pairing Strategies in Asymmetric Organocatalysis Book

Radical and Ion pairing Strategies in Asymmetric Organocatalysis


  • Author : Maxime R Vitale
  • Publisher : Elsevier
  • Release Date : 2017-07-21
  • Genre: Technology & Engineering
  • Pages : 184
  • ISBN 10 : 9780081011553

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Radical and Ion pairing Strategies in Asymmetric Organocatalysis Excerpt :

Considering the challenge of sustainability facing our society in the coming decades, catalysis is without any doubt a research area of major importance. In this regard, asymmetric organocatalysis, now considered a pillar of green chemistry, deserves particular attention. The first chapter of this volume examines the topic of asymmetric organocatalysis in light of radical chemistry. Recent important progress in this field has been attained by promoting the formation and harnessing the high reactivity of open-shell intermediates. Merging organocatalysis with radical chemistry has been the key to solving some longstanding bottlenecks, and has also significantly contributed to reinforcing the key role of organocatalysis in asymmetric catalysis. This chapter presents the most significant developments in this area, with a particular focus on asymmetric SOMO- and photoredox-organocatalyzed transformations. Chapter 2 focuses on quaternary ammonium salts (R4N+X-), especially chiral derivatives, and their behavior as unique catalysts in organocatalysis. Forming chiral ion-pairs capable of promoting asymmetric reactions, they also operate as unique “transporters involved in phase transfer catalytic processes between liquid–liquid or liquid–solid systems. Furthermore, they offer unique opportunities when forming cooperative ion-paired entities R4N+X-, allowing a synergistic implication of the counter-ion X- either as Brønsted bases or Lewis bases. Specific design of such chiral catalysts in modern chemistry and better insight into their mode of activation facilitates efficient and unprecedented chemical transformations. This chapter provides an overview of the use of chiral quaternary ammonium salts in organocatalysis, emphasizing both general mechanistic aspects and the scope of this approach. Presents the most significant developments with a particular focus on asymmetric SOMO- and photoredox-organocatalyzed transformations Givies a larger overview of chiral ammonium

Asymmetric Organocatalysis Book

Asymmetric Organocatalysis


  • Author : Benjamin List
  • Publisher : Springer
  • Release Date : 2012-05-04
  • Genre: Science
  • Pages : 460
  • ISBN 10 : 3642262791

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Asymmetric Organocatalysis Excerpt :

As nucleophiles, simple alkenes are typically so unreactive that only highly active electrophiles, such as carbocations, peroxides, and halogens will react with them. For the generation of carbon-carbon bonds, milder methods will often be required. Fortunately, it is possible to increase the reactivity of alkene-type p-nucleophiles by introducing electron-donating substituents. Substitution of one H with an OH or OR gives an enol or a vinyl ether, which are already much better nucleophiles. Using nitrogen instead of oxygen, one obtains even better nucleophiles, enamines. Enamines are among the most reactive neutral carbon nucleophiles, exhibiting rates that are even comparable to some charged nucleophiles, such as enolates [1, 2]. Most enamines, unfortunately, are sensitive to hydrolysis. The parent enamine, N,N-dimethylvinylamine, has in fact been prepared [3], but appears to be uns- ble. Enamines of cyclic ketones and many aldehydes can readily be isolated, however [4–7]. The instability of enamines might at first appear to diminish the utility of enamines as nucleophiles, but actually this property can be viewed as an added benefit: enamines can be readily and rapidly generated catalytically by using a suitable amine and a carbonyl compound. The condensation of aldehydes or ketones with amines initially affords an imine or iminium ion, which then rapidly loses a proton to afford the corresponding enamine (Scheme 1).

Dienamine Catalysis for Organic Synthesis Book

Dienamine Catalysis for Organic Synthesis


  • Author : Kengadarane Anebouselvy
  • Publisher : Royal Society of Chemistry
  • Release Date : 2018-03-02
  • Genre: Science
  • Pages : 206
  • ISBN 10 : 9781788014328

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Dienamine Catalysis for Organic Synthesis Excerpt :

In the past decade a new era in asymmetric catalysis has been realised by the discovery of L-proline induced chiral enamines from carbonyls. Inspired by this, researchers have developed many other primary catalytic species in situ, more recently secondary catalytic species such as aminals have been identified for use in asymmetric synthesis. High-yielding asymmetric synthesis of bioactive and natural products through mild catalysis is an efficient approach in reaction engineering. In the early days, synthetic chemists mainly focused on the synthesis of complex molecules, with less attention on the reaction efficiency and eco-friendly conditions. Recent investigations have been directed towards the development of atom economy, eco-friendly and enantioselective synthesis for more targeted and efficient synthesis. Building on the momentum of this rapidly expanding research area, Dienamine Catalysis for Organic Synthesis will provide a comprehensive introduction, from the preformed species, in situ generation and onto their applications in the synthesis of bioactive molecules and natural products.

Recent Advances in Organocatalysis Book

Recent Advances in Organocatalysis


  • Author : Iyad Karamé
  • Publisher : BoD – Books on Demand
  • Release Date : 2016-09-28
  • Genre: Science
  • Pages : 192
  • ISBN 10 : 9789535126720

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Recent Advances in Organocatalysis Excerpt :

Organocatalysis has recently attracted enormous attention as green and sustainable catalysis. It was realized as a fundamental field providing wide families of catalysts for important organic transformations. It will certainly develop in the future. Given the diversity of accessible transformations, metal-catalyzed reactions have become major tools in organic synthesis that will undoubtedly continue to have an important impact in the future. Alternatively, over the last years, a metal-free approach such as organocatalysis has reached a level of faithfulness, allowing researchers to discover new catalytic systems based on engagement of new or early-prepared organic molecules as organocatalysts. Organocatalysis meets green chemistry principles, especially the reduction of toxicity and chemical accidents, the biodegradability, and the use of benign and friendlier reaction media and conditions.

Organocatalysis Book

Organocatalysis


  • Author : Maurizio Benaglia
  • Publisher : Walter de Gruyter GmbH & Co KG
  • Release Date : 2021-07-19
  • Genre: Science
  • Pages : 451
  • ISBN 10 : 9783110590050

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Organocatalysis Excerpt :

Organocatalysis is considered today one of the three pillars in asymmetric catalysis, along with biocatalysis and organometallic catalysis. The possibility to combine organocatalysis with radical chemistry, photocatalysis and enabling technologies opened new avenues in organic synthesis.

Anion Binding Catalysis Book

Anion Binding Catalysis


  • Author : Olga Garcia-Mancheno
  • Publisher : John Wiley & Sons
  • Release Date : 2021-12-28
  • Genre: Technology & Engineering
  • Pages : 300
  • ISBN 10 : 9783527348572

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Anion Binding Catalysis Excerpt :

Explores the potential of new types of anion-binding catalysts to solve challenging synthetic problems Anion-Binding Catalysis introduces readers to the use of anion-binding processes in catalytic chemical activation, exploring how this approach can contribute to the future design of novel synthetic transformations. Featuring contributions by world-renowned scientists in the field, this authoritative volume describes the structure, properties, and catalytic applications of anions as well as synthetic applications and practical analytical methods. In-depth chapters are organized by type of catalyst rather than reaction type, providing readers with an accessible overview of the existing classes of effective catalysts. The authors discuss the use of halogens as counteranions, the combination of (thio)urea and squaramide-based anion-binding with other types of organocatalysis, anion-binding catalysis by pnictogen and tetrel bonding, nucleophilic co-catalysis, anion-binding catalysis by pnictogen and tetrel bonding, and more. Helping readers appreciate and evaluate the potential of anion-binding catalysis, this timely book: Illustrates the historical development, activation mode, and importance of anion-binding in chemical catalysis Explains the analytic methods used to determine the anion-binding affinity of the catalysts Describes catalytic and synthetic applications of common NH- and OH-based hydrogen-donor catalysts as well as C-H triazole/triazolium catalysts Covers amino-catalysis involving enamine, dienamine, or iminium activation approaches Discusses new trends in the field of anion-binding catalysis, such as the combination of anion-binding with other types of catalysis Presenting the current state of the field as well as the synthetic potential of anion-binding catalysis in future, Anion-Binding Catalysis is essential reading for researchers in both academia and industry involved in organic synthesis, homogeneous catalysis, and pharmaceutical chemistry.

Fluorous Chemistry Book

Fluorous Chemistry


  • Author : István T. Horváth
  • Publisher : Springer Science & Business Media
  • Release Date : 2011-11-04
  • Genre: Science
  • Pages : 414
  • ISBN 10 : 9783642252334

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Fluorous Chemistry Excerpt :

Structural, Physical, and Chemical Properties of Fluorous Compounds, by J.A. Gladysz Selective Fluoroalkylation of Organic Compounds by Tackling the “Negative Fluorine Effect”, by W. Zhang, C. Ni and J. Hu Synthetic and Biological Applications of Fluorous Reagents as Phase Tags, by S. Fustero, J. L. Aceña and S. Catalán Chemical Applications of Fluorous Reagents and Scavengers, by Marvin S. Yu Fluorous Methods for the Synthesis of Peptides and Oligonucleotides, by B. Miriyala Fluorous Organic Hybrid Solvents for Non-Fluorous Organic Synthesis, by I. Ryu Fluorous Catalysis: From the Origin to Recent Advances, by J.-M. Vincent Fluorous Organocatalysis, by W. Zhang Thiourea Based Fluorous Organocatalyst, by C. Cai Fluoroponytailed Crown Ethers and Quaternary Ammonium Salts as Solid–Liquid Phase Transfer Catalysts in Organic Synthesis, by G. Pozzi and R. H. Fish Fluorous Hydrogenation, by X. Zhao, D. He, L. T. Mika and I. T. Horváth Fluorous Hydrosilylation, by M. Carreira and M. Contel Fluorous Hydroformylation, by X. Zhao, D. He, L.T. Mika and I. Horvath Incorporation of Fluorous Glycosides to Cell Membrane and Saccharide Chain Elongation by Cellular Enzymes, by K. Hatanaka Teflon AF Materials, by H. Zhang and S. G. Weber Ecotoxicology of Organofluorous Compounds, by M. B. Murphy, E. I. H. Loi, K. Y. Kwok and P. K. S. Lam Biology of Fluoro-Organic Compounds, by X.-J. Zhang, T.-B. Lai and R. Y.-C. Kong

Modern Strategies for Heterocycle Synthesis Book

Modern Strategies for Heterocycle Synthesis


  • Author : Gianfranco Favi
  • Publisher : MDPI
  • Release Date : 2021-03-17
  • Genre: Medical
  • Pages : 372
  • ISBN 10 : 9783036503400

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Modern Strategies for Heterocycle Synthesis Excerpt :

Heterocycles feature widely in natural products, agrochemicals, pharmaceuticals and dyes, and their synthesis is of great interest to synthetic chemists in both academia and industry. The contributions of recent applications of new methodologies in C–H activation, photoredox chemistry, cross-coupling strategies, borrowing hydrogen catalysis, multicomponent and solvent-free reactions, regio- and stereoselective syntheses, as well as other new, attractive approaches for the construction of heterocyclic scaffolds are of great interest. This Special Issue is dedicated to featuring the latest research that is ongoing in the field of heterocyclic synthesis. It is expected that most submissions will focus on five- and six-membered oxygen and nitrogen-containing heterocycles, but structures incorporating other rings/heteroatoms will also be considered. Original research (communications, full papers and reviews) that discusses innovative methodologies for assembling heterocycles with potential application in materials, catalysis and medicine are therefore welcome.

New Organocatalytic Strategies for the Selective Synthesis of Centrally and Axially Chiral Molecules Book

New Organocatalytic Strategies for the Selective Synthesis of Centrally and Axially Chiral Molecules


  • Author : Nicola Di Iorio
  • Publisher : Springer
  • Release Date : 2018-04-11
  • Genre: Science
  • Pages : 157
  • ISBN 10 : 9783319749143

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New Organocatalytic Strategies for the Selective Synthesis of Centrally and Axially Chiral Molecules Excerpt :

This thesis discusses the use of asymmetric organic catalysis for the direct enantioselective synthesis of complex chiral molecules, and by addressing the many aspects of both vinylogy and atropisomerism, it appeals to researchers and scholars interested in both areas. Organocatalysis is a relatively modern and “hot” topic in the chemical community; it is constantly expanding and its use has been extended to interesting areas like vinylogous reactivity and atropisomerism. Vinylogous systems are very important for their synthetic applications but also pose a number of challenges, the most notable of which are their reduced reactivity and the reduced stereocontrol at these positions. On the other hand, atropisomeric systems are even more important because of the huge potential they have as drugs, ligands and catalysts. Chemists have only recently “recognized” the importance of these two areas and are focusing their efforts on studying them and the challenges they pose. This thesis offers an extensive introduction on the general aspects of chirality and organocatalysis and an equally extensive experimental section that allow nonexperts to understand the discussion section and reproduce the experiments.

Journal Book

Journal


  • Author : American Chemical Society
  • Publisher : Unknown
  • Release Date : 2003
  • Genre: Chemistry
  • Pages : null
  • ISBN 10 : NYPL:33433068513062

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Journal Excerpt :

Handbook of Synthetic Photochemistry Book

Handbook of Synthetic Photochemistry


  • Author : Angelo Albini
  • Publisher : John Wiley & Sons
  • Release Date : 2010-02-01
  • Genre: Science
  • Pages : 484
  • ISBN 10 : 9783527323913

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Handbook of Synthetic Photochemistry Excerpt :

Unique in its focus on preparative impact rather than mechanistic details, this handbook provides an overview of photochemical reactions classed according to the structural feature that is built in the photochemical step, so as to facilitate use by synthetic chemists unfamiliar with this topic. An introductory section covers practical questions on how to run a photochemical reaction, while all classes of the most important photocatalytic reactions are also included. Perfect for organic synthetic chemists in academia and industry.

Asymmetric Catalysis Book

Asymmetric Catalysis


  • Author : B. Bosnich
  • Publisher : Springer Science & Business Media
  • Release Date : 2012-12-06
  • Genre: Science
  • Pages : 172
  • ISBN 10 : 9789400951778

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Asymmetric Catalysis Excerpt :

The rate of advance in areas of science is seldom constant. Usually certain fields effloresce with activity because of the ~ealization that solutions are possible to long standing important problems. So it is now with asymmetric catalysis, a field which promises to change profoundly the strategic thinking of synthetic chemists. As this Report will show, reagents which can induce catalytic enantiocontrol of chemical transformations could represent the ultimate synthetic method. Nearly all synthetic strategies of complex molecules involve steps which require enantiocontrol and, in many cases, a specific catalytic transformation embodying enan tiocontrol has enormous advantages in terms of the rate and economy of the reaction. Because asymmetric catalysis is in a formative stage, workers with different backgrounds have joined the field. This Workshop had representatives with organometallic, organic, structural, kinetic, enzymatic, microbiological and industrial backgrounds. Each had his own perspective and this Report represents a consensus of this group of eleven people. The result is probably as compre hensive and balanced a view of the subject as is possible at present. It is hoped that those who have until now had but a glancing interest in asymmetric catalysis will find this Report a useful indication of its present state. We believe that asymmetric catalysis will have an increasing impact on the development of chemistry and will eventually dominate much of synthetic and industrial chemistry.

Asymmetric Organocatalysis Combined with Metal Catalysis Book

Asymmetric Organocatalysis Combined with Metal Catalysis


  • Author : Bruce A. Arndtsen
  • Publisher : Springer Nature
  • Release Date : 2020-04-24
  • Genre: Science
  • Pages : 205
  • ISBN 10 : 9783030438517

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Asymmetric Organocatalysis Combined with Metal Catalysis 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.The chapter "Enamine/Transition Metal Combined Catalysis: Catalytic Transformations Involving Organometallic Electrophilic Intermediates" is available open access under a CC BY 4.0 License via link.springer.com.

Dissertation Abstracts International Book

Dissertation Abstracts International


  • Author : Anonim
  • Publisher : Unknown
  • Release Date : 2008
  • Genre: Dissertations, Academic
  • Pages : null
  • ISBN 10 : STANFORD:36105133522040

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Dissertation Abstracts International Excerpt :

Asymmetric Bronsted Acid Catalysis Book

Asymmetric Bronsted Acid Catalysis


  • Author : Magnus Rueping
  • Publisher : John Wiley & Sons
  • Release Date : 2016-02-23
  • Genre: Science
  • Pages : 240
  • ISBN 10 : 9783527339174

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Asymmetric Bronsted Acid Catalysis Excerpt :

A much-needed overview of the synthesis of chiral Brønsted acids and their applications in various organic transformations. The internationally recognized and highly respected expert authors summarize the most significant advances in this new and dynamically progressing field, with a special emphasis on BINOL-derived phosphoric acids. They also describe other catalysts, such as C-H, TADDOL-derived Brønsted, and sulfonic acids. For easy navigation, the chapters are organized in the first instance according to reactive intermediate and then sub-divided by reaction type. An appendix with selected experimental details for benign and straight-forward procedures rounds of the book, making this the number-one information source for organic chemists in academia and industry.