Download or read book Development and Mechanistic Investigations of a Catalytic Asymmetric Conjugate Addition of Aromatic Thiols to Unsaturated Imides And Progress Toward the Total Synthesis of Bipinnatin I written by Qinghao Chen and published by . This book was released on 2006 with total page 189 pages. Available in PDF, EPUB and Kindle. Book excerpt: *Please refer to dissertation for diagrams.
Download or read book Catalytic Asymmetric Conjugate Reactions written by Armando Cordova and published by John Wiley & Sons. This book was released on 2010-12-01 with total page 489 pages. Available in PDF, EPUB and Kindle. Book excerpt: This unique and long-awaited handbook on this important topic in the hot field of stereoselective organic synthesis covers several types of nucleophiles. Top international authors deal with modern forms of achieving stereoselective conjugate additions based on the use of chiral auxiliaries or asymmetric catalysis, such as P-N ligands, organocatalysis, domino reactions, Lewis acid and base catalysis. There is also a discussion of the employment of enantioselective conjugate addition transformations in total synthesis of important molecules. With its reliable and previously unpublished experimental procedures, this is a true source of high quality information.
Download or read book Catalytic Asymmetric Friedel Crafts Alkylations written by Marco Bandini and published by John Wiley & Sons. This book was released on 2009-06-10 with total page 317 pages. Available in PDF, EPUB and Kindle. Book excerpt: This first comprehensive overview of this important synthetic reaction covers the whole spectrum of this modern and rapidly developing field. Clearly structured, the book presents all the known synthetic approaches for the construction of aromatic compounds bearing benzylic stereocenters with a defined configuration. With its representative synthetic procedures, organocatalysis and industrial applications it combines a theoretical basis with practical examples, resulting in valuable advice for beginners and experts alike. The ultimate source for every synthetic chemist in academia and industry.
Download or read book Organocatalytic Enantioselective Conjugate Addition Reactions written by Jose L Vicario and published by Royal Society of Chemistry. This book was released on 2010-10-18 with total page 365 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book, unique in its field, is a comprehensive description of all the methodologies reported for carrying out conjugate addition reactions in a stereoselective way, using small chiral organic molecules as catalysts (organocatalysts). In the last 3-4 years, this has been a rapidly growing field in organic chemistry, and many papers have appeared reporting excellent protocols for carrying out these highly efficient transformations that compete well with other classical approaches using transition metal catalysts. A particularly attractive feature of this transformation relies upon the fact that the conjugate addition (Michael and Hetero-Michael reactions) is an extraordinarily effective means to initiate cascade processes which result in the formation of complex molecules from very small and simple starting blocks. The book, written by noted experts, covers all recent advances in this hot topic, and provides a good state-of-the-art review for organic chemists working in this field and all those who wish to start projects in this area.
Download or read book Investigation of the Scope and Mechanism of the Palladium catalyzed Synthesis of Enantioenriched Allylic Esters from Prochiral Z allylic Alcohols and Progress Toward the Total Synthesis of massadine written by Jeffrey Scott Cannon and published by . This book was released on 2012 with total page 523 pages. Available in PDF, EPUB and Kindle. Book excerpt: In Chapter 1, a review of the development and applications of enantioselective palladium(II) catalysts for the reactions of allylic imidates is provided. Planar chiral catalysts containing a metallocene unit were found to be the optimal catalysts for palladium(II)-catalyzed reactions. Cobalt oxazoline palladacycles (COP) are the most effective catalysts known for the enantioselective rearrangement of allylic imidates as well as a number of allylic displacement reactions. In Chapter 2, the scope and mechanism of the COP-catalyzed reaction of prochiral (Z)-allylic trichloroacetimidates to form enantioenriched 3-carboxy-1-alkenes is investigated. The scope of this reaction was determined to be broad, tolerating a wide variety of organic functionality. Experimental and computational mechanistic analysis established that anti oxypalladation is the rate- and enantiodetermining step. DFT computational studies further established a model for enantioselectivity. In Chapter 3, a review of recent synthetic approaches to the oxidized dimeric pyrrole imidazole alkaloids is provided. The first total syntheses of massadine, axinellamines, and palau'amine are described. Reports of progress toward the total synthesis of these natural products are also summarized. In Chapter 4, progress toward the total synthesis of ( - )-massadine is reported. The synthetic route features two key steps. The first is an Ireland-Claisen rearrangement of a trianionic allylic acetate that occurs with high stereospecificity. The second is an unprecedented intramolecular nitrone dipolar cycloaddition which stereoselectively constructs a fully substituted cyclopentane. Elaboration of cyclopentane intermediates to incorporate the bisguanidine functionality is described.
Download or read book Catalytic Methods in Asymmetric Synthesis written by Michelangelo Gruttadauria and published by John Wiley & Sons. This book was released on 2011-07-05 with total page 720 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book covers advances in the methods of catalytic asymmetric synthesis and their applications. Coverage moves from new materials and technologies to homogeneous metal-free catalysts and homogeneous metal catalysts. The applications of several methodologies for the synthesis of biologically active molecules are discussed. Part I addresses recent advances in new materials and technologies such as supported catalysts, supports, self-supported catalysts, chiral ionic liquids, supercritical fluids, flow reactors and microwaves related to asymmetric catalysis. Part II covers advances and milestones in organocatalytic, enzymatic and metal-based mediated asymmetric synthesis, including applications for the synthesis of biologically active molecules. Written by leading international experts, this book consists of 16 chapters with 2000 References and illustrations of 560 schemes and figures.
Download or read book Catalytic Asymmetric Synthesis of Allylic Aryl Ethers and Progress Toward the Total Synthesis of Palau amine Axinellamines A D and Massadine written by Nicole Suzanne White and published by . This book was released on 2009 with total page 574 pages. Available in PDF, EPUB and Kindle. Book excerpt: In chapter 2, the isolation, characterization, and biological activity of the pyrrole-imidazole alkaloids palau'amine, axinellamines A--D and massadine are reviewed. The proposed biosynthesis of these alkaloids is described and several synthetic approaches toward these alkaloids are discussed.
Download or read book The Development of an Asymmetric Palladium catalyzed Conjugate Addition and Its Application Toward the Total Syntheses of Taiwaniaquinoid Natural Products written by Jeffrey Clinton Holder and published by . This book was released on 2014 with total page 1056 pages. Available in PDF, EPUB and Kindle. Book excerpt: The asymmetric synthesis of quaternary stereocenters remains a challenging problem in organic synthesis. Past work from the Stoltz laboratory has resulted in methodology to install quaternary stereocenters [alpha]- or [gamma]- to carbonyl compounds. Thus, the asymmetric synthesis of [beta]-quaternary stereocenters was a desirable objective, and was accomplished by engineering the palladium-catalyzed addition of arylmetal organometallic reagents to [alpha],[beta]-unsaturated conjugate acceptors.
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 Total Synthesis of dihydroprotolichesterinic Acid Via a Diastereoselective Conjugate Addition Development of Enantioselective Halocyclization Reactions and Progress Towards the Total Synthesis of Jiadifenolide written by John Caleb Hethcox and published by . This book was released on 2015 with total page 784 pages. Available in PDF, EPUB and Kindle. Book excerpt: In an effort to develop a unified route to functionalized succinic acid derivatives, a new diastereoselective conjugate addition of monoorganocuprates, Li[RCuI], to a chiral fumarate was developed. The conjugate addition proceeded with good yields and a high degree of diastereoselectivity for a variety of alkyl and aryl nucleophiles. Application of this new methodology culminated in the shortest total synthesis of (-)-dihydroprotolichisterenic acid to date. The novel organocatalyst developed by the Martin group was applied to enantioselective iodolactonization reactions. Reaction conditions were optimized and the resulting halolactones were obtained in high yields and enantioselectivities for a number of olefinic acids. Of particular note is the disclosure of the first iodolactonization reactions forming a C-I bond at a stereogenic center. The utility of this catalyst was further extended to kinetic resolution reactions. Additionally, this catalyst was found to promote the first enantioselective halolactamization reaction with moderate enantioselectivity. Finally, the catalyst was modified in an effort to enhance the enantioselectivity and verify the proposed bifunctional nature of the catalyst. Lastly, an enantiospecific total synthesis of the neurotrophic sesquiterpenoid natural product (-)-jiadifenolide was progressed. The stereochemistry was introduced by the use of commercially available (+)-pulegone as the starting material. The first diastereoselective decarboxylative allylation on a cyclopentanone was developed A samarium diiodide mediated radical annulation was planned to forge two of the rings, and late stage oxidation manipulation could then lead to the completion of the synthesis.
Download or read book Organocatalytic Asymmetric Conjugate Addition of Heteroaryl Moieties to unsaturated Enones Using Boronates and 3 3 disubstituted Binaphthols written by Didi Chiu Yee Cheung and published by . This book was released on 2012 with total page 91 pages. Available in PDF, EPUB and Kindle. Book excerpt: Asymmetric conjugate addition is an important methodology for carbon-carbon bond formation in organic synthesis. While there is extensive literature on the asymmetric conjugate addition of a wide selection of donors to a variety of acceptors, there are relatively few reports on the asymmetric conjugate addition of heteroaryl groups. Almost all of these reports utilize catalytic amounts of both a rhodium compound and a chiral ligand, and usually employ organoboron reagents. Furthermore, these additions have been problematic due to protodeboronation. Other organocatalytic methods have offered low yields and moderate enantioselectivies. The binaphthol / boronate catalyst system developed by the Chong group is effective in promoting asymmetric conjugate addition of 2-thienyl, 3-thienyl, 2-furyl, and 2-benzo[b]thienyl moieties to acyclic enones. The combination of 3,3ʹ-disubstituted binaphthols with diethyl heteroarylboronates generated 1,4-adducts with good yields and high enantioselectivities (up to 100% yield and 99.9:0.1 er). This catalyst system complements known methods of conjugate addition of heteroaryl groups involving transition metal catalysts and cyclic enone acceptors and is the most effective organocatalytic system reported to date.
Download or read book Organocatalytic Asymmetric Conjugate Addition of Heteroaryl Moieties to alpha beta unsaturated Enones Using Boronates and 3 3 disubstituted Binaphthols written by Didi Chiu Yee Cheung and published by . This book was released on 2012 with total page 91 pages. Available in PDF, EPUB and Kindle. Book excerpt: Asymmetric conjugate addition is an important methodology for carbon-carbon bond formation in organic synthesis. While there is extensive literature on the asymmetric conjugate addition of a wide selection of donors to a variety of acceptors, there are relatively few reports on the asymmetric conjugate addition of heteroaryl groups. Almost all of these reports utilize catalytic amounts of both a rhodium compound and a chiral ligand, and usually employ organoboron reagents. Furthermore, these additions have been problematic due to protodeboronation. Other organocatalytic methods have offered low yields and moderate enantioselectivies. The binaphthol / boronate catalyst system developed by the Chong group is effective in promoting asymmetric conjugate addition of 2-thienyl, 3-thienyl, 2-furyl, and 2-benzo[b]thienyl moieties to acyclic enones. The combination of 3,3ʹ-disubstituted binaphthols with diethyl heteroarylboronates generated 1,4-adducts with good yields and high enantioselectivities (up to 100% yield and 99.9:0.1 er). This catalyst system complements known methods of conjugate addition of heteroaryl groups involving transition metal catalysts and cyclic enone acceptors and is the most effective organocatalytic system reported to date.
Download or read book Mechanistic Investigations Into the Palladium catalyzed Decarboxylative Allylic Alkylation of Ketone Enolates Using the PHOX Ligand Architecture written by Nathaniel Haynes Sherden and published by . This book was released on 2011 with total page 350 pages. Available in PDF, EPUB and Kindle. Book excerpt: Palladium-catalyzed asymmetric allylic alkylation has become a large and important field for chemical synthesis. Many methodologies in this field offer mild conditions under which challenging and important molecular features can be reliably synthesized, including chiral all-carbon quaternary stereocenters. As a result, palladium- catalyzed asymmetric allylic alkylation has found significant use in total synthesis, and growing use in industry. While the general process of palladium-catalyzed asymmetric allylic alkylation has been studied for decades, there have been a number of recent modifications and developments, such as asymmetric versions of decarboxylative allylic alkylation procedures that are not yet well understood. The development of future implementations and improvements to palladium-catalyzed asymmetric allylic alkylation and related methodologies is expected to be facilitated by a better understanding of these more recent developments, and thus further mechanistic investigation is warranted. Reported herein is a set of investigations into the palladium-catalyzed decarboxylative asymmetric allylic alkylation of ketone enolates using the PHOX ligand architecture. By monitoring the reaction via 31P NMR, a series of previously unidentified key intermediates is discovered. Two representatives of these key intermediates are isolated and characterized. The solution behavior of these species under reaction-like conditions is studied along with a few novel and related complexes. The role of these intermediates and their impact on the behavior of the reaction and product formation is discussed. Previously confounding experimentally observed behavior for this methodology is rationalized via the properties elucidated for these discovered intermediates.
Download or read book Copper catalyzed Asymmetric Conjugate Addition of Alkenyl and Alkylalanes to unsaturated Lactams written by Pierre Cottet and published by . This book was released on 2014 with total page 90 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Design and Development of New Enantioselective Catalytic Reactions and Progress Towards the Total Synthesis of Callipeltoside A written by John Jacob Moely Wiener and published by . This book was released on 2004 with total page 366 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Catalytic Asymmetric Synthesis written by Iwao Ojima and published by Wiley. This book was released on 1993-08-13 with total page 476 pages. Available in PDF, EPUB and Kindle. Book excerpt: Widely acknowledged as one of today's most desirable, challenging, and economically advantageous techniques, Catalytic Asymmetric Synthesis promotes the creation of millions of chiral product molecules with a single chiral catalyst molecule and serves as a valuable method for obtaining enantiomerically pure or enriched compounds. Offering a thorough account of the significance, usefulness and major advances in catalytic asymmetric synthesis over the past decade, Catalytic Asymmetric Synthesis documents the explosive development of increasingly efficient and reliable methods for the synthesis of desired compounds in an enantiomerically pure state. Featuring contributions from K. Barry Sharpless, Ryoji Noyori, Hisashi Yamamoto, Eric N. Jacobson, Henri B. Kagan, Henri Brunner, Tamio Hayashi, Hidemasa Takaya, and other internationally renowned authorities, coverage provides detailed accounts of today's most important catalytic asymmetric reactions. Audience: Catalytic Asymmetric Synthesis is an essential reference for medicinal, agricultural, natural products, and synthetic organic chemists at all levels, as well as professionals in the pharmaceutical and agricultural industries.
Download or read book Catalytic Asymmetric Synthesis written by Iwao Ojima and published by Wiley-VCH. This book was released on 1993-01-01 with total page 496 pages. Available in PDF, EPUB and Kindle. Book excerpt: Widely acknowledged as one of today's most desirable, challenging, and economically advantageous techniques, Catalytic Asymmetric Synthesis promotes the creation of millions of chiral product molecules with a single chiral catalyst molecule and serves as a valuable method for obtaining enantiomerically pure or enriched compounds. Offering a thorough account of the significance, usefulness and major advances in catalytic asymmetric synthesis over the past decade, Catalytic Asymmetric Synthesis documents the explosive development of increasingly efficient and reliable methods for the synthesis of desired compounds in an enantiomerically pure state. Featuring contributions from K. Barry Sharpless, Ryoji Noyori, Hisashi Yamamoto, Eric N. Jacobson, Henri B. Kagan, Henri Brunner, Tamio Hayashi, Hidemasa Takaya, and other internationally renowned authorities, coverage provides detailed accounts of today's most important catalytic asymmetric reactions. Audience: Catalytic Asymmetric Synthesis is an essential reference for medicinal, agricultural, natural products, and synthetic organic chemists at all levels, as well as professionals in the pharmaceutical and agricultural industries.
