Download or read book Novel Applications of Magnesium Base Systems in Preparative Organic Chemistry and Asymmetric Synthesis written by Peter Katai and published by . This book was released on 2018 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Extending Applications of Magnesium Amide Bases in Asymmetric Synthesis and a Mild and Selective N debenzylation Method written by Natalie R. Monks and published by . This book was released on 2013 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Expansion of the application of readily available chiral magnesium-bisamides was the overall focus of the majority of this study. Comparing a structurally simple C2-symmetric magnesium bisamide and a chelating magnesium bisamide, a range of cyclobutanone substrates have been desymmetrised. Early studies employed the chlorotriethylsilane electrophile, however, efficiency of the processes with the chosen base system with cyclobutanone substrates was low. When the alternative electrophile, diphenylphosphoryl chloride, was utilised, however, a drastic improvement in both reactivity and selectivity was achieved. Optimisation of the reaction conditions with both a C2-symmetric magnesium bisamide and a chelating magnesium bisamide revealed selectivities of up to 99:1 er for the enantioenriched enol phosphate products. Furthermore, it was found that no additives are required within this novel base system and the deprotonation can be performed at a more elevated temperature of -40 °C whilst maintaining high selectivity. This efficient desymmetrisation was applied to a range of cyclobutanone substrates and seven novel enol phosphate products were formed in enantioselectivities between 76:24 and 99:1er, with the majority producing ratios greater than 89:11 er. Further application of a C2-symmetric magnesium bisamide was also sought by employing this base reagent within the synthetic route towards the natural product (+)-(S)-Sporochnol A. To this end, a scalable pathway towards a novel 4,4-disubstituted cyclohexanone was devised. The asymmetric deprotonation of this intermediate, utilising a C2-symmetric magnesium bisamide, subsequently embedded the all carbon quaternary stereocentre required within the natural product. Trapping the resulting chiral enolate with diphenylphosphoryl chloride furnished the desired enol phosphate in 88:12 er, which is an excellent level of enantioselectivity for a substrate of this type at a reaction temperature of -78 °C. Furthermore, the utility of the enol phosphate product was highlighted through a palladium-catalysed cross-coupling reaction with a Grignard reagent. Although completion of the synthesis of (+)-(S)-Sporochnol A was not achieved, the key asymmetric deprotonation and subsequent cross-coupling step were successful and high yielding. An additional study was the development of an improved method for the oxidation of secondary N-benzylamines. The application of DIAD as a means to oxidise secondary N-benzylamines, followed by a subsequent hydrolysis step has been employed to afford debenzylated free amines. This oxidation methodology has thus been applied to a range of amine substrates as an improved, mild, and selective method for benzyl deprotection. High yields of the free amines were obtained and the reaction proved to be tolerant of other functional groups and heteroatoms. Moreover, when an enantiopure secondary N-benzylamine was deprotected, the free primary amine remained optically pure, proving that these mild conditions do not interfere with other functionality within the molecule.
Download or read book The Development and Application of Magnesium Amide Bases in Asymmetric Synthesis written by Linsey S. Bennie and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Alkaline Earth Metal Compounds written by Sjoerd Harder and published by Springer. This book was released on 2013-07-20 with total page 282 pages. Available in PDF, EPUB and Kindle. Book excerpt: The series Topics in Organometallic Chemistry presents critical overviews of research results in organometallic chemistry. As our understanding of organometallic structure, properties and mechanisms increases, new ways are opened for the design of organometallic compounds and reactions tailored to the needs of such diverse areas as organic synthesis, medical research, biology and materials science. Thus the scope of coverage includes a broad range of topics in pure and applied organometallic chemistry, where new breakthroughs are being achieved that are of significance to a larger scientific audience. The individual volumes of Topics in Organometallic Chemistry are thematic. Review articles are generally invited by the volume editors.
Download or read book Superbases for Organic Synthesis written by Tsutomu Ishikawa and published by John Wiley & Sons. This book was released on 2009-01-26 with total page 336 pages. Available in PDF, EPUB and Kindle. Book excerpt: Guanidines, amidines and phosphazenes have been attracting attention in organic synthesis due to their potential functionality resulting from their extremely strong basicity. They are also promising catalysts because of their potential for easy molecular modification, possible recyclability, and reduced or zero toxicity. Importantly, these molecules can be derived as natural products – valuable as scientists move towards “sustainable chemistry”, where reagents and catalysts are derived from biomaterial sources. Superbases for Organic Synthesis is an essential guide to these important molecules for preparative organic synthesis. Topics covered include the following aspects: an introduction to organosuperbases physicochemical properties of organic superbases amidines and guanidines in organic synthesis phosphazene: preparation, reaction and catalytic role polymer-supported organosuperbases application of organosuperbases to total synthesis related organocatalysts: proton sponges and urea derivatives amidines and guanidines in natural products and medicines Superbases for Organic Synthesis is a comprehensive, authoritative and up-to-date guide to these important reagents for organic chemists, drug discovery researchers and those interested in the chemistry of natural products.
Download or read book Book of Abstracts written by and published by . This book was released on 2000 with total page 778 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book American Doctoral Dissertations written by and published by . This book was released on 1999 with total page 848 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Enantioselective Chemical Synthesis written by Elias J. Corey and published by Elsevier. This book was released on 2013-10-23 with total page 334 pages. Available in PDF, EPUB and Kindle. Book excerpt: Written by world-renowned and best-selling experts, Nobel Laureate E. J. Corey and Laszlo Kurti, Enantioselective Chemical Synthesis offers an authoritative and comprehensive overview of the field’s progress; the processes and tools for key formations; future development for complex, stereocontrolled (enantiomeric or diastereoisomeric) molecules; and valuable examples of multi-step syntheses. Utilizing a color-coded scheme to illustrate chemical transformations, Enantioselective Chemical Synthesis provides clear explanation and guidance through vital asymmetrical syntheses and insight into the next steps for the field. Researchers, professionals, and academics will benefit from this valuable, thorough, and unique resource. In Part I, the authors present clearly, comprehensively and concisely the most useful enantioselective processes available to synthetic chemists. Part II provides an extensive discussion of the most logical ways to apply these new enantioselective methods to the planning of syntheses of stereochemically complex molecules. This hitherto neglected area is essential for the advancement of enantioselective synthesis to a more rational and powerful level. Part III describes in detail many reaction sequences which have been used successfully for the construction of a wide variety of complex target molecules Clearly explains stereochemical synthesis in theory and practice Provides a handy tool box for scientists wishing to understand and apply chiral chemical synthesis Describes almost 50 real life examples of asymmetric synthesis in practice and examines how the chiral centers were introduced at key synthetic stages
Download or read book Dissertation Abstracts International written by and published by . This book was released on 2003 with total page 768 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 676 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 Principles and Applications of Asymmetric Synthesis written by Guo-Qiang Lin and published by John Wiley & Sons. This book was released on 2003-05-29 with total page 536 pages. Available in PDF, EPUB and Kindle. Book excerpt: Asymmetric synthesis remains a challenge to practicing scientistsas the need for enantiomerically pure or enriched compoundscontinues to increase. Over the last decade, a large amount ofliterature has been published in this field. Principles andApplications of Asymmetric Synthesis consolidates and evaluates themost useful methodologies into a one-volume resource for theconvenience of practicing scientists and students. Authored by internationally renowned scientists in the field, thisreliable reference covers more than 450 reactions and includesimportant stoichiometric as well as catalytic asymmetric reactions.The first chapter reviews the basic principles, commonnomenclature, and analytical methods, and the remainder of the bookis organized according to reaction type. The text examines suchtopics as: Carbon-carbon bond formations involving carbonyls, enamines,imines, and enolates Asymmetric C-O bond formations including epoxidation,dihydroxylation, and aminohydroxylation Asymmetric synthesis using the Diels-Alder reaction and othercyclizations Applications to the total synthesis of natural products Use of enzymes in asymmetric synthesis Practicing chemists in the pharmaceutical, fine chemical, andagricultural professions as well as graduate students will findthat Principles and Applications of Asymmetric Synthesis affordscomprehensive and current coverage.
Download or read book Side Reactions in Organic Synthesis written by Florencio Zaragoza Dörwald and published by John Wiley & Sons. This book was released on 2006-03-06 with total page 389 pages. Available in PDF, EPUB and Kindle. Book excerpt: Most syntheses in the chemical research laboratory fail and usually require several attempts before proceeding satisfactorily. Failed syntheses are not only discouraging and frustrating, but also cost a lot of time and money. Many failures may, however, be avoided by understanding the structure-reactivity relationship of organic compounds. This textbook highlights the competing processes and limitations of the most important reactions used in organic synthesis. By allowing chemists to quickly recognize potential problems this book will help to improve their efficiency and success-rate. A must for every graduate student but also for every chemist in industry and academia. Contents: 1 Organic Synthesis: General Remarks 2 Stereoelectronic Effects and Reactivity 3 The Stability of Organic Compounds 4 Aliphatic Nucleophilic Substitutions: Problematic Electrophiles 5 The Alkylation of Carbanions 6 The Alkylation of Heteroatoms 7 The Acylation of Heteroatoms 8 Palladium-Catalyzed C-C Bond Formation 9 Cyclizations 10 Monofunctionalization of Symmetric Difunctional Substrates
Download or read book Boronic Acids written by Dennis G. Hall and published by John Wiley & Sons. This book was released on 2006-05-12 with total page 571 pages. Available in PDF, EPUB and Kindle. Book excerpt: For the first time, the whole field of organoboronic acids is presented in one comprehensive handbook. Professor Dennis Hall, a rising star within the community, covers all aspects of this important substance class, including applications in chemistry, biology and medicine. Starting with an introduction to the structure, properties, and preparation of boronic acid derivatives, together with an overview of their reactions and applications, the book goes on to look at metal-catalyzed borylation of alkanes and arenas, coupling reactions and rhodium-catalyzed additions of boronic acids to alkenes and carbonyl compounds. There follows chapters on copper-promoted C-O and C-N cross-coupling of boronic acids, recent applications in organic synthesis, as well as alpha-haloalkylboronic esters in asymmetric synthesis. Later sections deal with cycloadditions, organoboronic acids, oxazaborolidines as asymmetric inducers, and boronic acid based receptors and sensors. The whole is rounded off with experimental procedures, making this invaluable reading for organic, catalytic and medicinal chemists, as well as those working in organometallics.
Download or read book Microreactors in Organic Synthesis and Catalysis written by Thomas Wirth and published by John Wiley & Sons. This book was released on 2008-09-08 with total page 297 pages. Available in PDF, EPUB and Kindle. Book excerpt: This one-stop reference is the first book on this emerging and rapid developing field with a focus on synthesis and catalysis. As such, it covers all aspects from academia and industry in a clearly structured way. Leading experts provide the background information as an initial aid for newcomers to the field, while chapters on different reaction types and industrial applications make this an equally vital resource for specialists.
Download or read book Sustainable Chemistry written by Michael North and published by Royal Society of Chemistry. This book was released on 2016 with total page 506 pages. Available in PDF, EPUB and Kindle. Book excerpt: Focussing on catalysis through non-endangered metals, this book is an important reference for researchers working in catalysis and green chemistry.
Download or read book Organoboranes for Syntheses written by P. Veeraraghavan Ramachandran and published by . This book was released on 2001 with total page 272 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book examines the recent advances in the art of organic synthesis via organoboranes. The volume includes a wide range of topics in asymmetric synthesis, such as reduction, aldol reaction, allyboration, homologation, and cyclopropanation. Additional subjects include Suzuki coupling, amino acid synthesis, fluoro-organic synthesis, boron catalysts for stereoselective transformations, heterocyclic synthesis and novel borohydride reagents.
