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Enantioselective Synthesis Of Natural Products Containing Tertiary Alcohols And Contributions To A Total Synthesis Of Phorbasin B
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Book Synopsis Enantioselective Synthesis of Natural Products Containing Tertiary Alcohols and Contributions to a Total Synthesis of Phorbasin B by :
Download or read book Enantioselective Synthesis of Natural Products Containing Tertiary Alcohols and Contributions to a Total Synthesis of Phorbasin B written by and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Studies in Natural Products Chemistry by : Atta-ur Rahman
Download or read book Studies in Natural Products Chemistry written by Atta-ur Rahman and published by Elsevier. This book was released on 2013-10-22 with total page 541 pages. Available in PDF, EPUB and Kindle. Book excerpt: Studies in Natural Products Chemistry Volume 12: Stereoselective Synthesis (Part H) reviews the stereoselective synthetic and mechanistic chemistry of bicyclomycin. It discusses chemical studies of the taxane diterpenes; the synthetic methodology for 2-amino alcohols of biological interest; and the synthesis and structure of hydroxylated indolizidines. Some of the topics covered in the book are the synthetic routes to the oxahydrindene subunit of the avermectin-milbemycin family of antiparasitic agents; isolation, structure elucidation, biosynthesis, and biological activity of the avermectins; two-stage coupling process of macrolide antibiotics synthesis; and synthesis of the rifamycin S ansa-chain compound. The complete synthesis of erythromycin A is also covered. The role of isocyanides in the synthesis of beta lactam antibiotics and the characteristics of the beta lactam antibiotics are discussed. The development of an A-Ring annulation strategy for taxane synthesis is also presented. A chapter is devoted to the advances in the synthesis of tumor-promoting diterpenes. The book can provide useful information to chemists, biologists, students, and researchers.
Book Synopsis Strategies and Tactics in Organic Synthesis by : Jenny B. Werness
Download or read book Strategies and Tactics in Organic Synthesis written by Jenny B. Werness and published by Elsevier Inc. Chapters. This book was released on 2013-07-29 with total page 25 pages. Available in PDF, EPUB and Kindle. Book excerpt: Addition of halogen and nucleophiles to conjugated 1,3-enynes in a 1,4-fashion produces a chiral allene and a stereogenic center. The diastereo- and enantioselectivity of this process are discussed in detail. The 1,4-bromoetherification of 1,3-enynes can be applied to the synthesis of various bromoallene-containing natural products. Our diastereo- and enantioselective total synthesis of kumausallene is described in this chapter. The synthesis features a cascade reaction involving palladium-catalyzed desymmetrization and a DMF-mediated diastereoselective 1,4-bromoetherification reaction.
Book Synopsis The Enantioselective Synthesis of Complex Natural Products by : Ryan E. Stites
Download or read book The Enantioselective Synthesis of Complex Natural Products written by Ryan E. Stites and published by . This book was released on 2005 with total page 162 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Enantioselective Total Synthesis of Diketopiperazinecontaining Natural Products: (-)-Lansai B, (+)-Nocardioazines a and B, and (-)-Acetylapoaranotin by : Haoxuan Wang
Download or read book Enantioselective Total Synthesis of Diketopiperazinecontaining Natural Products: (-)-Lansai B, (+)-Nocardioazines a and B, and (-)-Acetylapoaranotin written by Haoxuan Wang and published by . This book was released on 2015 with total page 666 pages. Available in PDF, EPUB and Kindle. Book excerpt: Diketopiperazine (DKP) motif is found in a wide range of biologically active natural products. This work details our efforts toward two classes of DKP-containing natural products. Class one features the pyrroloindoline structure, derived from tryptophans. Our group developed a highly enantioselective (3 + 2) formal cycloaddition between indoles and acrylates to provide pyrroloindoline products possessing three stereocenters. Utilizing this methodology, we accomplished asymmetric total synthesis of three natural products: (-)-lansai B, (+)-nocardioazines A and B. Total synthesis of (-)-lansai B was realized in six steps, and featured an amino acid dimerization strategy. The total synthesis of (+)-nocardioazine B was also successfully completed in ten steps. Challenges were met in approaching (+)-nocardioazine A, where a seemingly easy last-step epoxidization did not prove successful. After re-examining our synthetic strategy, an early-stage epoxidation strategy was pursued, which eventually yielded a nine-step total synthesis of (+)-nocardioazine A. Class two is the epidithiodiketopiperazine (ETP) natural products, which possesses an additional episulfide bridge in the DKP core. With the goal of accessing ETPs with different peripheral structures for structure-activity relationship studies, a highly divergent route was successfully developed, which was showcased in the formal synthesis of (-)-emethallicin E and (-)-haematocin, and the first asymmetric synthesis of (-)-acetylapoaranotin.
Book Synopsis Enantioselective Synthesis by : Tse-Lok Ho
Download or read book Enantioselective Synthesis written by Tse-Lok Ho and published by Wiley-Interscience. This book was released on 1992-02-18 with total page 340 pages. Available in PDF, EPUB and Kindle. Book excerpt: In recent years the intense activities of enantioselective synthesis have been reflected in the burgeoning and ingenious applications of such natural substances as carbohydrates, -amino acids and terpenes. A comprehensive summary of terpene-based synthesis is offered, focusing on synthetic efforts using transformed chiral synthons. The author provides analysis of synthetic strategies and discusses the intricacies of reaction courses. Along with the number and variety of natural products derived from chiral terpenes, numerous flow-charts aid in clearly delineating synthetic pathways.
Book Synopsis Development of the Enantioselective Oxidation of Secondary Alcohols and Natural Products Total Synthesis by : Jeffrey Thomas Bagdanoff
Download or read book Development of the Enantioselective Oxidation of Secondary Alcohols and Natural Products Total Synthesis written by Jeffrey Thomas Bagdanoff and published by . This book was released on 2006 with total page 758 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Principles of Asymmetric Synthesis by : R.E. Gawley
Download or read book Principles of Asymmetric Synthesis written by R.E. Gawley and published by Elsevier. This book was released on 1996-11-21 with total page 395 pages. Available in PDF, EPUB and Kindle. Book excerpt: The world is chiral. Most of the molecules in it are chiral, and asymmetric synthesis is an important means by which enantiopure chiral molecules may be obtained for study and sale. Using examples from the literature of asymmetric synthesis (more than 1300 references), the aim of this book is to present a detailed analysis of the factors that govern stereoselectivity in organic reactions. It is important to note that the references were each individually checked by the authors to verify relevance to the topics under discussion. The study of stereoselectivity has evolved from issues of diastereoselectivity, through auxiliary-based methods for the synthesis of enantiomerically pure compounds (diastereoselectivity followed by separation and auxiliary cleavage), to asymmetric catalysis. In the latter instance, enantiomers (not diastereomers) are the products, and highly selective reactions and modern purification techniques allow preparation - in a single step - of chiral substances in 99% ee for many reaction types. After an explanation of the basic physical-organic principles of stereoselectivity, the authors provide a detailed, annotated glossary of stereochemical terms. A chapter on "Analytical Methods" provides a critical overview of the most common methods for analysis of stereoisomers. The authors then follow the 'tried-and-true' format of grouping the material by reaction type. Thus, there are four chapters on carbon-carbon bond forming reactions (enolate alkylations, organometal additions to carbonyls, aldol and Michael reactions, and cycloadditions and rearrangements), one chapter on reductions and hydroborations (carbon-hydrogen bond forming reactions), and one on oxidations (carbon-oxygen and carbon-nitrogen bond forming reactions). Leading references are provided to natural product synthesis that have been accomplished using a given reaction as a key step. In addition to tables of examples that show high selectivity, a transition state analysis is presented to explain - to the current level of understanding - the stereoselectivity of each reaction. In one case (Cram's rule) the evolution of the current theory is detailed from its first tentative (1952) postulate to the current Felkin-Anh-Heathcock formalism. For other reactions, only the currently accepted rationale is presented. Examination of these rationales also exposes the weaknesses of current theories, in that they cannot always explain the experimental observations. These shortcomings provide a challenge for future mechanistic investigations.
Book Synopsis Enantioselective Chemical Synthesis by : Elias J. Corey
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
Book Synopsis Enantioselective Total Synthesis Of Diverse, Bioactive Natural Products by :
Download or read book Enantioselective Total Synthesis Of Diverse, Bioactive Natural Products written by and published by . This book was released on 2007 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Natural product synthesis is one of the most creative branch of chemistry in terms of its boundless scope for innovation and has stimulated several generations of synthetic organic chemists. With advancement in the technology, particularly in the isolation and purification techniques, high-field NMR and X-ray crystallography, it has become fairly routine to isolate and assign the structures, high-field NMR and X-ray crystallography, it has become fairly routine to isolate and assign the structures, even to those complex molecules, which are available only in microscopic quantities from natural sources. Concurrently, one has witnessed tremendous advances in the availability of new synthetic methodologies with high region-, stereo-, and enantiocontrol for one or multiple C-C bond formations and rapid generation of molecular complexity. These developments have rekindled interest with total synthesis of natural products as platforms for testing and validating new reactions and strategies. Many natural products exhibit wide range of biological activities and thus provide good leads in drug discovery but quite often such bioactive compounds are obtained only in minute quantities from Nature. Hence, there is need to synthesize them to obtain requisite quantities and build diversity around their scaffold to further explore their therapeutic potential. Thus, natural product synthesis combines both intellectual challenge and possible application for human wellbeing. Our research group is actively engaged in the synthesis of structurally complex, bioactive natural products and as a part of this endeavour, total syntheses of several bioactive compounds have been accomplished in our laboratory in recent past. The present thesis has also evolved around the ongoing theme directed towards natural product synthesis and is organized under three chapters. Chapter I: Total synthesis of (+)-1S-Minwanenone Chapter II: Enantioselective total synthesis of the bioactive natural product (+)-
Book Synopsis Enantioselective Total Synthesis Of Bioactive Epoxyquinoid Natural Products by :
Download or read book Enantioselective Total Synthesis Of Bioactive Epoxyquinoid Natural Products written by and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Total synthesis of natural products with diverse architecture and varying degree of complexity is an area that has not only inspired and attracted several generations of organic chemists but also continues to enrich and refresh the foundations of organic chemistry itself, by offering new ideas and directions. Synthetic organic chemistry is perhaps the most formative and expressive enterprise of science in terms of its creative power and unlimited scope. Its impact on present day life and prosperity gets manifested when we see this science as the bedrock behind the production of pharmaceuticals, pesticides, fertilizers, nutritional products, high tech materials, polymers, cosmetics, plastics and clothing. Science of synthesis is also going to play an important role in the evolution of future societies based on the principles of the sustainable development. Being a precise science and a fine art, the endeavor of total synthesis is in a constant state of effervescence. Most significantly, the discipline is being continually challenged by new structures unraveled from the Nature bosom. The practice of total synthesis is being enriched constantly by new tools such as new reagents and catalysts as well as by analytical techniques. In fact, there has been a dramatic advancement in the recent past in the development of new synthetic protocols with high regio-, streo-, and enantiocontrol, which makes it possible to target natural product of any complexity. The demand for enantiomerically pure drugs, agrochemicals and food additives is growing, since pure enantiomers are often more target-specific and have fewer side effects than the recemic mixtures. As a result, synthesis of natural products in an enantioselective manner has been receiving increasing attention from synthetic chemists in recent years. Nature synthesizes a vast array of novel molecular structures in enantioselective fashion through several well-established biosynthetic pathways utilizing a few key building.
Book Synopsis Application of Enantioselective Dihalogenation to the Total Synthesis of Terpene Natural Products by : Cyril Bucher
Download or read book Application of Enantioselective Dihalogenation to the Total Synthesis of Terpene Natural Products written by Cyril Bucher and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Halogenated natural products are ubiquitous and in many cases display promising biomedical potential. Due to the scarcity of methods for the stereoselective incorporation of halides into organic substrates and the difficulty of isolation from nature, access to most members for anticancer screening is severely limited. We were able to leverage an advancement made in our laboratory, which allows for chemo-, regio-, and enantioselective synthesis of vicinal dihalide products, toward the stereoselective total synthesis of several polyhalogenated natural products. One of these compounds, halomon, was tested on the Bassik laboratory target identification screen, which identified an interesting pathway that serves to export the drug from the cancer cell. We have further shown that enriched dihalides can act as novel forms of chiral, removable auxiliaries that enable synthesis of stereocenters that are difficult to access with traditional methods.
Book Synopsis Formation of Contiguous Stereogenic Quaternary Carbon Centers in Natural Products Synthesis by : Emily Anne Peterson
Download or read book Formation of Contiguous Stereogenic Quaternary Carbon Centers in Natural Products Synthesis written by Emily Anne Peterson and published by . This book was released on 2005 with total page 404 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis alpha-Hydroxy Acids in Enantioselective Syntheses by : Gary M. Coppola
Download or read book alpha-Hydroxy Acids in Enantioselective Syntheses written by Gary M. Coppola and published by Wiley-VCH. This book was released on 1997-03-27 with total page 524 pages. Available in PDF, EPUB and Kindle. Book excerpt: Gary M. Coppola Herbert F. Schuster alpha;-Hydroxy Acids in Enantioselective Syntheses An ideal synthesis starts with readily accessible reagents and yields the target molecules in high optical purity. The naturally available alpha;-hydroxy acids, lactic, malic, mandelic and tartaric acids, provide the chemist with chiral building blocks for the introduction of one or more asymmetric centers into an organic molecule. This book not only supplies a comprehensive discussion of useful reactions but also demonstrates how complex molecules can have their origin in simple, readily accessible chirally pure starting materials. The authors, both practicing medicinal research chemists, aim at providing information for the design and synthesis of chiral molecules. A particularly attractive feature of this text is the excellent schemes used to illustrate the crucial transformations. All structures are represented in their absolute stereochemistry. Mechanisms as well as insights into the execution of a synthetic pathway are discussed concisely, with a focus on practical aspects. The authors have drawn on their years of writing experience to supply graduate students, research chemists and teachers alike with a gold mine of useful chemistry. Every synthetic chemist will want to have this invaluable resource at his or her disposal.
Book Synopsis Studies Towards the Enantioselective Synthesis of Aspidosperma Natural Products by : Christopher Gartshore
Download or read book Studies Towards the Enantioselective Synthesis of Aspidosperma Natural Products written by Christopher Gartshore and published by . This book was released on 2013 with total page 209 pages. Available in PDF, EPUB and Kindle. Book excerpt: The indole alkaloid (-)-aspidophytine was isolated from Haplophyton cimicidium, a plant traditionally known throughout Mexico for its insecticidal properties. The structural complexity of (-)-aspidophytine, characterized by the presence of a bridging lactone and unsaturation in the C ring appended to the characteristic aspidosperma [6.5.6.6.5] ABCDE ring system, has made it an appealing target for total synthesis. This thesis details studies focused on the development of new chemical reactions, and strategies, applicable to the enantioselective synthesis of aspidosperma alkaloids, in particular (-)-aspidophytine. The first chapter provides an introduction to the natural product (-)-aspidophytine and its parent compound (+)-haplophytine, detailing previous synthetic approaches, and the specific challenges expected in realising this goal. The latter section describes the development of new approaches suited to the synthesis of (-)-aspidophytine. Chapter two introduces the application of transition metal/nitroxide based oxidation reactions for the kinetic resolution and desymmetrisation of alcohols. The chapter then details the synthesis and application of a range of chiral racemic bi-functional nitroxide catalysts for the oxidation of activated alcohols. The employment of these catalysts to the synthesis of a range of aldehydes is outlined and efforts towards the development of enantioselective variant are discussed. The third chapter of this thesis details the development of a palladium catalyzed enantioselective decarboxylative allylation reaction of heterocycles bearing the indolone motif. The reaction provided an expedient approach to the synthesis of enantioenriched indolecontaining heterocycles with good yields and high levels of enantioinduction achieved. The scope of this reaction was examined with the synthesis of a range of functionalised carbazolones and indolones achieved. Having successful assembled a range of enantioenriched carbazolones, chapter four discusses the derivatisation of these substrates towards the synthesis of aspidosperma natural products. Challenges encountered when attempting to construct the aspidosperma tetracyclic core are detailed, specifically, formation of the D-ring and diastereoselective reduction of the resultant cyclic imine are outlined. In addition, manipulation of the allyl functionality is outlined culminating in the formal synthesis of (-)-aspidophytine. Chapter five of this thesis describes a related class of compounds belonging to the kopsia family of alkaloids. This chapter gives a brief introduction to kopsia alkaloids, specifically the recently discovered (+)-kopsihainanine A and B, then details efforts towards the synthesis of these compounds from the enantioenriched carbazolones introduced in chapter 3. The chapter concludes by outlining the first enantioselective formal synthesis of (+)-kopsihainanine A. Finally, the sixth chapter contains experimental procedures utilised within this project and the spectroscopic data derived from the compounds introduced in the preceding chapters.
Book Synopsis Stereoselective Synthesis by : Atta-ur Rahman
Download or read book Stereoselective Synthesis written by Atta-ur Rahman and published by Studies in Natural Products Ch. This book was released on 1993 with total page 540 pages. Available in PDF, EPUB and Kindle. Book excerpt: Section 1
Book Synopsis Towards the Total Synthesis of Natural Products (-)-Englerin A and Crotogoudin by : Dmitry B. Ushakov
Download or read book Towards the Total Synthesis of Natural Products (-)-Englerin A and Crotogoudin written by Dmitry B. Ushakov and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
