Download or read book Organocatalytic Dynamic Kinetic Resolution written by Hélène Pellissier and published by Royal Society of Chemistry. This book was released on 2022-05-06 with total page 171 pages. Available in PDF, EPUB and Kindle. Book excerpt: In a classical kinetic resolution, two enantiomers of a racemate are transformed into chiral products at different rates with a maximum theoretical yield of 50%. However, the need to reduce costs and waste in synthesis have led to efforts to develop novel resolution procedures proceeding beyond this 50% limited yield. This has led to the evolution of classical kinetic resolution into dynamic kinetic resolution (DKR), allowing a quantitative yield of one of the enantiomers. DKR combines the resolution step of kinetic resolution with an in-situ racemization of the chirally-labile substrate. It is only in the last two decades that chiral green organocatalysts have been demonstrated to be capable of promoting DKRs considerably expanding the synthetic scope of the powerful concept of DKR. Collecting all the developments in the field of DKR, this book shows that a wide variety of organocatalysts allow excellent levels of stereocontrol and yields in many types of transformations. It is a great resource for academics and industrialists interested in green enantioselective catalytic reactions.

Download or read book Non Metal Catalyzed Synthesis written by Yunfei Du and published by Walter de Gruyter GmbH & Co KG. This book was released on 2023-12-04 with total page 360 pages. Available in PDF, EPUB and Kindle. Book excerpt: Non-metal catalysis may provide new and green methods for obtaining bioactive heterocycles. Many catalysts contain metals, which can be toxic, energy intensive to remove, and require mining of the source materials. By utilizing metal-free catalysts we avoid these issues. This book explores the use of non-metal catalysts when synthesizing various heterocyclic structures with bioactivity.

Download or read book Chirality from Dynamic Kinetic Resolution written by Hélène Pellissier and published by Royal Society of Chemistry. This book was released on 2011 with total page 319 pages. Available in PDF, EPUB and Kindle. Book excerpt: The last 15 years have witnessed significant developments in the efficiency and scope of the application of DKR. These now offer a serious alternative to conventional methods for asymmetric synthesis. Indeed, impressive examples using new enzymes and major progress in the DKR of racemates have taken place over the past few years. The powerful combination of enzymes and metals has also been the subject of spectacular development. In addition, a new type of DKR, involving organocatalysts, has recently appeared. Although asymmetric catalysis has undergone development during the last two decades, the most common industrial process used to obtain enantiomerically pure compounds is still via resolution of racemic mixtures. This is despite the major disadvantage that only a maximum of 50% product yield can be obtained. It is not surprising that DKR, which solves the problem of the limitation in yield, has attracted an increasing amount of interest from both the industrial and the academic perspective. This book provides an up-date on the principle methods employed to obtain dynamic kinetic resolution (DKR) by either enzymatic or non-enzymatic methods. It also illustrates the diversity of useful chiral products that can be obtained through this powerful concept. Divided into three sections, the book deals successively with non-enzymatic methods, enzymatic methods, and the use of transition metals and enzymes in tandem.

Download or read book Asymmetric Synthesis II written by Mathias Christmann and published by John Wiley & Sons. This book was released on 2013-03-19 with total page 406 pages. Available in PDF, EPUB and Kindle. Book excerpt: After the overwhelming success of Asymmetric Synthesis - The Essentials, displaying a broad range of organic asymmetric syntheses, this is the second edition with latest subjects and authors. While the aim of the first edition was mainly to honor the achievements of the pioneers in asymmetric syntheses, the aim of this new edition was bringing the current developments, especially from younger colleagues, to the attention of students. The format of the book remained unchanged, i.e. short conceptual overviews by young leaders in their field including a short biography of the authors. The growing multidisciplinary research within chemistry is reflected in the selection of topics including metal catalysis, organocatalysis, physical organic chemistry, analytical chemistry, and its applications in total synthesis, materials research and industry. The prospective reader of this book is a graduate or undergraduate student of advanced organic chemistry as well as the industrial chemist who wants to get a brief update on the current developments in the field.

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 Biocatalysis in Asymmetric Synthesis written by Gonzalo De Gonzalo and published by Elsevier. This book was released on 2024-05-04 with total page 522 pages. Available in PDF, EPUB and Kindle. Book excerpt: Biocatalysis in Asymmetric Synthesis, a new volume in the Foundations and Frontiers of Enzymology series, offers an applied discussion of synthesizing biological catalysts using asymmetric synthesis, for applications across research and industry. Here, global experts in the field analyze a wide variety of biocatalysts and their physical states, process conditions for their asymmetric synthesis, solvents required during synthesis, and even downstream procedures for the recovery of final products. The book adopts an interdisciplinary approach, merging fundamental biology and its synthetic applications across industries, with a wide range of practical examples, from directed evolution to biotransformation and production of novel enzymes and non-conventional catalysts. Throughout the book, the impact and application of biocatalysis in sustainable processing is considered in-depth. This book will also help non-experts in biocatalysis to apply this knowledge in their own research, providing a thorough overview of the ways asymmetric biocatalytic approaches may be adapted for different disciplines and downstream products. - Explores biocatalysts as exquisite catalysts for fine chiral compound synthesis in different reaction media - Features both foundational overviews and applied, practical examples across research and industry - Includes chapter contributions from international leaders in the field

Download or read book Practical Process Research and Development written by Neal G. Anderson and published by Elsevier. This book was released on 2000-06-05 with total page 380 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides a comprehensive, step-by-step approach to organic process research and development in the pharmaceutical, fine chemical, and agricultural chemical industries. Process R&D describes the steps taken, following synthesis and evaluation, to bring key compounds to market in a cost-effective manner. More people are being hired for work in this area as increasing numbers of drug candidates are identified through combinatorial chemistry and high-throughput screening. The book is directed to industrial (primarily organic) chemists, and academicians (particularly those involved in a growing number of start-up companies) and students who need insight into industrial process R&D. Current books do not describe hands-on, step-by-step, approaches to solving process development problems, including route, reagent, and solvent selection; optimising catalytic reactions; chiral syntheses; and "green chemistry." "Practical Process Research and Development" will be a valuable resource for researchers, managers, and graduate students. - Provides insights into generating rugged, practical, cost-effective processes for the chemical preparation of "small molecules" - Breaks down process optimization into route, reagent and solvent selection, development of reaction conditions, workup, crystallizations and more - Includes over 100 tips for rapid process development - Presents guidelines for implementing and troubleshooting processes

Download or read book Asymmetric Synthesis of Drugs and Natural Products written by Ahindra Nag and published by CRC Press. This book was released on 2018-01-12 with total page 498 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book focuses on different techniques of asymmetric synthesis of important compounds, such as drugs and natural products. It gives insightful information on recent asymmetric synthesis by Inorganic, Organic and Enzymatic combinations. It also emphasizes chiral compounds and design of new catalyst for synthesis of compounds.

Download or read book Catalytic Asymmetric Synthesis written by Takahiko Akiyama and published by John Wiley & Sons. This book was released on 2022-05-27 with total page 798 pages. Available in PDF, EPUB and Kindle. Book excerpt: Catalytic Asymmetric Synthesis Seminal text presenting detailed accounts of the most important catalytic asymmetric reactions known today This book covers the preparation of enantiomerically pure or enriched chemical compounds by use of chiral catalyst molecules. While reviewing the most important catalytic methods for asymmetric organic synthesis, this book highlights the most important and recent developments in catalytic asymmetric synthesis. Edited by two well-qualified experts, sample topics covered in the work include: Metal catalysis, organocatalysis, photoredox catalysis, enzyme catalysis C–H bond functionalization reactions Carbon–carbon bond formation reactions, carbon–halogen bond formation reactions, hydrogenations, polymerizations, flow reactions Axially chiral compounds Retaining the best of its predecessors but now thoroughly up to date with the important and recent developments in catalytic asymmetric synthesis, the 4th edition of Catalytic Asymmetric Synthesis serves as an excellent desktop reference and text for researchers and students, from upper-level undergraduates all the way to experienced professionals in industry or academia.

Download or read book Frontiers of Green Catalytic Selective Oxidations written by Konstantin P. Bryliakov and published by Springer Nature. This book was released on 2019-10-02 with total page 298 pages. Available in PDF, EPUB and Kindle. Book excerpt: The demand for novel efficient and environmentally sustainable chemo, regio- and stereoselective catalyst systems for the oxidation of organic substrates is continuously growing in line with toughening economic and environmental constraints. This book addresses these issues; it consists of eleven chapters written by world-recognized experts in green and sustainable oxidation catalysis. The most urgent and challenging topics, in the judgment of the editor, such as green asymmetric epoxidations, sulfoxidatiuons, C–H oxidations; oxidation catalysis by polyoxometalates and oxidations in non-conventional solvents, etc. have been critically reviewed in this book. Both fundamental aspects, such as catalysts design, catalytic properties, nature of catalytically active sites and reaction mechanisms, and practical outlook of the oxidations have been addressed by the authors. The book appeals to a broad readership, particularly graduate students, employees of universities and research organizations, and industrial researchers, particularly those working in the areas of homogeneous oxidation catalysis, asymmetric synthesis, organocatalysis, sustainable catalytic processes and green chemistry, mechanisms of catalytic reactions, synthesis of bioactive compounds, biomimetic chemistry, etc. Konstantin Bryliakov is Leading Researcher at the Boreskov Institute of Catalysis. In 2016, he was elected Honorary Professor of the Russian Academy of Sciences.

Download or read book Asymmetric and Selective Biocatalysis written by Jose M. Palomo and published by MDPI. This book was released on 2019-04-12 with total page 154 pages. Available in PDF, EPUB and Kindle. Book excerpt: This Issue contains one communication, six articles, and two reviews. The communication from Paola Vitale et al. represents a work where whole cells were used as biocatalysts for the reduction of optically active chloroalkyl arylketones followed by a chemical cyclization to give the desired heterocycles. Among the various whole cells screened (baker’s yeast, Kluyveromyces marxianus CBS 6556, Saccharomyces cerevisiae CBS 7336, Lactobacillus reuteri DSM 20016), baker’s yeast provided the best yields and the highest enantiomeric ratios (95:5) in the bioreduction of the above ketones. In this respect, valuable chiral non-racemic functionalized oxygen-containing heterocycles (e.g., (S)-styrene oxide, (S)-2-phenyloxetane, (S)-2-phenyltetrahydrofuran), amenable to be further elaborated on, can be smoothly and successfully generated from their prochiral precursors. Studies about pure biocatalysts with mechanistical studies, application in different reactions, and new immobilization methods for improving their stability were reported in five different articles. The article by Su-Yan Wang et al. describes the cloning, expression, purification, and characterization of an N-acetylglucosamine 2-epimerase from Pedobacter heparinus (PhGn2E). For this, several N-acylated glucosamine derivatives were chemically synthesized and used to test the substrate specificity of the enzyme. The mechanism of the enzyme was studied by hydrogen/deuterium NMR. The study at the anomeric hydroxyl group and C-2 position of the substrate in the reaction mixture confirmed the epimerization reaction via ring-opening/enolate formation. Site-directed mutagenesis was also used to confirm the proposed mechanism of this interesting enzyme. The article by Forest H. Andrews et al. studies two enzymes, benzoylformate decarboxylase (BFDC) and pyruvate decarboxylase (PDC), which catalyze the non-oxidative decarboxylation of 2-keto acids with different specificity. BFDC from Pseudomonas putida exhibited very limited activity with pyruvate, whereas the PDCs from S. cerevisiae or from Zymomonas mobilis showed virtually no activity with benzoylformate (phenylglyoxylate). After studies using saturation mutagenesis, the BFDC T377L/A460Y variant was obtained, with 10,000-fold increase in pyruvate/benzoylformate. The change was attributed to an improvement in the Km value for pyruvate and a decrease in the kcat value for benzoylformate. The characterization of the new catalyst was performed, providing context for the observed changes in the specificity. The article by Xin Wang et al. compares two types of biocatalysts to produce D-lysine L-lysine in a cascade process catalyzed by two enzymes: racemase from microorganisms that racemize L-lysine to give D,L-lysine and decarboxylase that can be in cells, permeabilized cells, and the isolated enzyme. The comparison between the different forms demonstrated that the isolated enzyme showed the higher decarboxylase activity. Under optimal conditions, 750.7 mmol/L D-lysine was finally obtained from 1710 mmol/L L-lysine after 1 h of racemization reaction and 0.5 h of decarboxylation reaction. D-lysine yield could reach 48.8% with enantiomeric excess (ee) of 99%. In the article by Rivero and Palomo, lipase from Candida rugosa (CRL) was highly stabilized at alkaline pH in the presence of PEG, which permitted its immobilization for the first time by multipoint covalent attachment on different aldehyde-activated matrices. Different covalent immobilized preparation of the enzyme was successfully obtained. The thermal and solvent stability was highly increased by this treatment, and the novel catalysts showed high regioselectivity in the deprotection of per-O-acetylated nucleosides. The article by Robson Carlos Alnoch et al. describes the protocol and use of a new generation of tailor-made bifunctional supports activated with alkyl groups that allow the immobilization of proteins through the most hydrophobic region of the protein surface and aldehyde groups that allows the covalent immobilization of the previously adsorbed proteins. These supports were especially used in the case of lipase immobilization. The immobilization of a new metagenomic lipase (LipC12) yielded a biocatalyst 3.5-fold more active and 5000-fold more stable than the soluble enzyme. The PEGylated immobilized lipase showed high regioselectivity, producing high yields of the C-3 monodeacetylated product at pH 5.0 and 4 °C. Hybrid catalysts composed of an enzyme and metallic complex are also treated in this Special Issue. The article by Christian Herrero et al. describes the development of the Mn(TpCPP)-Xln10A artificial metalloenzyme, obtained by non-covalent insertion of Mn(III)-meso-tetrakis(p-carboxyphenyl)porphyrin [Mn(TpCPP), 1-Mn] into xylanase 10A from Streptomyces lividans (Xln10A). The complex was found able to catalyze the selective photo-induced oxidation of organic substrates in the presence of [RuII(bpy)3]2+ as a photosensitizer and [CoIII(NH3)5Cl]2+ as a sacrificial electron acceptor, using water as oxygen atom source. The two published reviews describe different subjects with interest in the fields of biocatalysis and mix metallic-biocatalysis, respectively. The review by Anika Scholtissek et al. describes the state-of-the-art regarding ene-reductases from the old yellow enzyme family (OYEs) to catalyze the asymmetric hydrogenation of activated alkenes to produce chiral products with industrial interest. The dependence of OYEs on pyridine nucleotide coenzyme can be avoided by using nicotinamide coenzyme mimetics. In the review, three main classes of OYEs are described and characterized. The review by Yajie Wang and Huimin Zhao highlights some of the recent examples in the past three years that combine transition metal catalysis with enzymatic catalysis. With recent advances in protein engineering, catalyst synthesis, artificial metalloenzymes, and supramolecular assembly, there is great potential to develop more sophisticated tandem chemoenzymatic processes for the synthesis of structurally complex chemicals. In conclusion, these nine publications give an overview of the possibilities of different catalysts, both traditional biocatalysts and hybrids with metals or organometallic complexes to be used in different processes—particularly in synthetic reactions—under very mild reaction conditions.

Download or read book Asymmetric Catalysis on Industrial Scale written by Hans Ulrich Blaser and published by John Wiley & Sons. This book was released on 2011-08-04 with total page 517 pages. Available in PDF, EPUB and Kindle. Book excerpt: This second edition of the pioneering work on this hot topic captures the major trends and latest achievements in the art of asymmetric catalysis on an industrial scale. A number of completely new real-life case studies written by the world leaders in their respective areas provide a compact and qualified insight into this developing field. The resulting ready reference and handbook collates first-hand and valuable information within a context where it can be easily found. The high-quality contributions illustrate the relevant environments and situations, such as time pressure, how the catalytic step fits into the overall synthesis, or competition with other synthetic approaches, as well as the typical problems encountered in the various phases, including finding/developing the catalyst and optimization of the process or choice of equipment. Both successful and unsuccessful approaches to solve these problems are described.

Download or read book Asymmetric Synthesis of Bioactive Lactones and the Development of a Catalytic Asymmetric Synthesis of Aryl Ketones written by Robert Doran and published by Springer. This book was released on 2015-06-24 with total page 218 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis addresses two fundamental areas in contemporary organic chemistry: synthesis of natural products and catalytic asymmetric synthesis. Firstly, a new methodology, developed by our research group, which allows the asymmetric synthesis of lactones, a structural unit ubiquitous in natural products, was utilised in the synthesis of a number of natural product analogues that showed significant biological activity. Secondly, the development of a catalytic asymmetric synthesis of a key structural motif present in a number of natural products and pharmaceuticals was accomplished. During the course of this work we discovered dual stereo control, which is significant because it allows the configuration of a new stereo centre to be controlled by a simple change of proton source.

Download or read book Handbook for Chemical Process Research and Development written by Wenyi Zhao and published by CRC Press. This book was released on 2016-11-03 with total page 864 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Handbook for Chemical Process Research and Development focuses on developing processes for chemical and pharmaceutical industries. Forty years ago there were few process research and development activities in the pharmaceutical industry, partially due to the simplicity of the drug molecules. However, with the increasing structural complexity, especially the introduction of chiral centers into the drug molecules and strict regulations set by the EMA and FDA, process R&D has become one of the critical departments for pharmaceutical companies. This book assists with the key responsibility of process chemists to develop chemical processes for manufacturing pharmaceutical intermediates and final drug substances for clinical studies and commercial production.

Download or read book Asymmetric Synthesis with Chemical and Biological Methods written by Dieter Enders and published by John Wiley & Sons. This book was released on 2007-04-09 with total page 472 pages. Available in PDF, EPUB and Kindle. Book excerpt: Edited by two of the leading researchers in the field, this book provides a deep, interdisciplinary insight into stoichiometric and catalytic reactions in this continuously expanding area. A plethora of top German scientists with an international reputation covers various aspects, from classical organic chemistry to process development, and from the theoretical background to biological methods using enzymes. Throughout the focus is on the development of new synthetic methods in asymmetric synthesis, the synthesis of natural and bioactive compounds and the latest developments in both chemical and biological methods of catalysis, as well as the investigation of special technical and biotechnical aspects.

Download or read book Dynamic Kinetic Resolution DKR and Dynamic Kinetic Asymmetric Transformations DYKAT written by Jan-E. Bäckvall and published by Georg Thieme Verlag. This book was released on 2022-12-07 with total page 544 pages. Available in PDF, EPUB and Kindle. Book excerpt: Principles and applications of DKR and DYKAT DKR and DYKAT are of ever increasing importance in the synthesis of enantiomerically enriched compounds. The preparation of enantiomerically pure compounds is of great importance in society today, in particular in pharmaceutical chemistry and in the agrochemical sector. Kinetic resolution is a popular method for differentiating two enantiomers in a racemic mixture that react at different rates with a chiral catalyst or reagent. The drawback of kinetic resolution is that the yield of one pure enantiomer is limited to a maximum of 50%. To overcome this limitation, an in situ racemization of the starting material can be combined with a kinetic resolution. This combination leads to a so called “dynamic kinetic resolution” (DKR), where the two enantiomers are in equilibrium with one another. The slow-reacting enantiomer will continuously be converted into the fast-reacting one, when the latter is transformed into the enantiomerically pure product. Thus, a racemic starting material can be transformed in catalytic processes into a single isomer of a chiral compound in up to 100% yield. DKR only applies to the resolution of racemic mixtures and the involvement of enantiomers leads to simple kinetics. When diastereomers, either as starting materials or as diastereomeric intermediates, are involved in the resolution process under dynamic conditions (via equilibria between diastereomers), the kinetics is different from DKR. These reactions are classified as “dynamic kinetic asymmetric transformations” (DYKAT). This volume covers the principles of DKR and DYKAT and presents examples of organocatalytic, chemoenzymatic, and transition-metal catalyzed approaches, including applications in the synthesis of complex, biologically active compounds.

Download or read book Asymmetric Organic Synthesis with Enzymes written by Vicente Gotor and published by John Wiley & Sons. This book was released on 2008-03-31 with total page 348 pages. Available in PDF, EPUB and Kindle. Book excerpt: Perfect for biochemists, synthetic and organic chemists, this book covers all important reactions, including C-C coupling reactions, oxidation reactions and many more. Divided into two parts, the first section on methodology presents new innovative methods for enzymatic catalysis optimization, including such new trends as medium engineering, directed evolution and computer-aided prediction of enantioselectivity. The second and main section deals with applications to synthesis, showing important reaction types and their applications. Only those reactions with very high selectivity are presented, allowing readers to improve their own reaction yields.