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Applications Of Palladium Catalyzed Enantioselective Decarboxylative Alkylation In Natural Products Total Synthesis
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Book Synopsis Applications of Palladium-catalyzed Enantioselective Decarboxylative Alkylation in Natural Products Total Synthesis by : Ryan Michael McFadden
Download or read book Applications of Palladium-catalyzed Enantioselective Decarboxylative Alkylation in Natural Products Total Synthesis written by Ryan Michael McFadden and published by . This book was released on 2008 with total page 1148 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Palladium-catalyzed Decarboxylative and Decarbonylative Transformations in the Synthesis of Fine and Commodity Chemicals by : Yiyang Liu
Download or read book Palladium-catalyzed Decarboxylative and Decarbonylative Transformations in the Synthesis of Fine and Commodity Chemicals written by Yiyang Liu and published by . This book was released on 2015 with total page 1012 pages. Available in PDF, EPUB and Kindle. Book excerpt: Decarboxylation and decarbonylation are important reactions in synthetic organic chemistry, transforming readily available carboxylic acids and their derivatives into various products through loss of carbon dioxide or carbon monoxide. In the past few decades, palladium-catalyzed decarboxylative and decarbonylative reactions experienced tremendous growth due to the excellent catalytic activity of palladium. Development of new reactions in this category for fine and commodity chemical synthesis continues to draw attention from the chemistry community. The Stoltz laboratory has established a palladium-catalyzed enantioselective decarboxylative allylic alkylation of beta-keto esters for the synthesis of alpha-quaternary ketones since 2005. Recently, we extended this chemistry to lactams due to the ubiquity and importance of nitrogen-containing heterocycles. A wide variety of alpha-quaternary and tetrasubstituted alpha-tertiary lactams were obtained in excellent yields and exceptional enantioselectivities using our palladium-catalyzed decarboxylative allylic alkylation chemistry. Enantioenriched alpha-quaternary carbonyl compounds are versatile building blocks that can be further elaborated to intercept synthetic intermediates en route to many classical natural products. Thus our chemistry enables catalytic asymmetric formal synthesis of these complex molecules. In addition to fine chemicals, we became interested in commodity chemical synthesis using renewable feedstocks. In collaboration with the Grubbs group, we developed a palladium-catalyzed decarbonylative dehydration reaction that converts abundant and inexpensive fatty acids into value-added linear alpha olefins. The chemistry proceeds under relatively mild conditions, requires very low catalyst loading, tolerates a variety of functional groups, and is easily performed on a large scale. An additional advantage of this chemistry is that it provides access to expensive odd-numbered alpha olefins. Finally, combining features of both projects, we applied a small-scale decarbonylative dehydration reaction to the synthesis of alpha-vinyl carbonyl compounds. Direct alpha-vinylation is challenging, and asymmetric vinylations are rare. Taking advantage of our decarbonylative dehydration chemistry, we were able to transform enantioenriched delta-oxocarboxylic acids into quaternary alpha-vinyl carbonyl compounds in good yields with complete retention of stereochemistry. Our explorations culminated in the catalytic enantioselective total synthesis of (-)-aspewentin B, a terpenoid natural product featuring a quaternary alpha-vinyl ketone. Both decarboxylative and decarbonylative chemistries found application in the late stage of the total synthesis.
Book Synopsis Artificial Metalloenzymes and MetalloDNAzymes in Catalysis by : Montserrat Diéguez
Download or read book Artificial Metalloenzymes and MetalloDNAzymes in Catalysis written by Montserrat Diéguez and published by John Wiley & Sons. This book was released on 2018-02-21 with total page 431 pages. Available in PDF, EPUB and Kindle. Book excerpt: An important reference for researchers in the field of metal-enzyme hybrid catalysis Artificial Metalloenzymes and MetalloDNAzymes in Catalysis offers a comprehensive review of the most current strategies, developed over recent decades, for the design, synthesis, and optimization of these hybrid catalysts as well as material about their application. The contributors—noted experts in the field—present information on the preparation, characterization, and optimization of artificial metalloenzymes in a timely and authoritative manner. The authors present a thorough examination of this interesting new platform for catalysis that combines the excellent selective recognition/binding properties of enzymes with transition metal catalysts. The text includes information on the various applications of metal-enzyme hybrid catalysts for novel reactions, offers insights into the latest advances in the field, and contains an informative perspective on the future: Explores the development of artificial metalloenzymes, the modern and strongly evolving research field on the verge of industrial application Contains a comprehensive reference to the research area of metal-enzyme hybrid catalysis that has experienced tremendous growth in recent years Includes contributions from leading researchers in the field Shows how this new catalysis combines the selective recognition/binding properties of enzymes with transition metal catalysts Written for catalytic chemists, bioinorganic chemists, biochemists, and organic chemists, Artificial Metalloenzymes and MetalloDNAzymes in Catalysis offers a unique reference to the fundamentals, concepts, applications, and the most recent developments for more efficient and sustainable synthesis.
Book Synopsis Total Synthesis of Bioactive Natural Products by Palladium-Catalyzed Domino Cyclization of Allenes and Related Compounds by : Shinsuke Inuki
Download or read book Total Synthesis of Bioactive Natural Products by Palladium-Catalyzed Domino Cyclization of Allenes and Related Compounds written by Shinsuke Inuki and published by Springer Science & Business Media. This book was released on 2011-11-23 with total page 115 pages. Available in PDF, EPUB and Kindle. Book excerpt: The author has developed novel methodologies for highly efficient construction of functionalized heterocycles by palladium-catalyzed domino/cascade cyclization of allenes and related compounds containing appropriate nucleophilic group(s). Based on these methodologies, enantioselective total syntheses of bioactive natural products, pachastrissamine (26% overall yield in seven steps), lysergic acid (4.0% overall yield in fifteen steps), lysergol (3.6% overall yield in fifteen steps) and isolysergol (8.2% overall yield in eleven steps) have been achieved. These are more facile synthetic route than those previously reported. These findings would contribute to the development of efficient synthetic methods for biologically active compounds containing a complex structure.
Book Synopsis Transition Metal Catalyzed Enantioselective Allylic Substitution in Organic Synthesis by : Uli Kazmaier
Download or read book Transition Metal Catalyzed Enantioselective Allylic Substitution in Organic Synthesis written by Uli Kazmaier and published by Springer. This book was released on 2011-10-28 with total page 354 pages. Available in PDF, EPUB and Kindle. Book excerpt: Giovanni Poli, Guillaume Prestat, Frédéric Liron, Claire Kammerer-Pentier: Selectivity in Palladium Catalyzed Allylic Substitution.- Jonatan Kleimark and Per-Ola Norrby: Computational Insights into Palladium-mediated Allylic Substitution Reactions.- Ludovic Milhau, Patrick J. Guiry: Palladium-catalyzed enantioselective allylic substitution.- Wen-Bo Liu, Ji-Bao Xia, Shu-Li You: Iridium-Catalyzed Asymmetric Allylic Substitutions.- Christina Moberg: Molybdenum- and Tungsten-Catalyzed Enantioselective Allylic Substitutions.- Jean-Baptiste Langlois, Alexandre Alexakis: Copper-catalyzed enantioselective allylic substitution.- Jeanne-Marie Begouin, Johannes E. M. N. Klein, Daniel Weickmann, B. Plietker: Allylic Substitutions Catalyzed by Miscellaneous Metals.- Barry M. Trost, Matthew L. Crawley: Enantioselective Allylic Substitutions in Natural Product Synthesis.
Book Synopsis Palladium-catalyzed Asymmetric Allylic Alkylation by : Nathan Bruce Bennett
Download or read book Palladium-catalyzed Asymmetric Allylic Alkylation written by Nathan Bruce Bennett and published by . This book was released on 2013 with total page 1828 pages. Available in PDF, EPUB and Kindle. Book excerpt: The asymmetric construction of quaternary stereocenters is a topic of great interest in the organic chemistry community given their prevalence in natural products and biologically active molecules. Over the last decade, the Stoltz group has pursued the synthesis of this challenging motif via a palladium-catalyzed allylic alkylation using chiral phosphinooxazoline (PHOX) ligands. Recent results indicate that the alkylation of lactams and imides consistently proceeds with enantioselectivities substantially higher than any other substrate class previously examined in this system. This observation prompted exploration of the characteristics that distinguish these molecules as superior alkylation substrates, resulting in newfound insights and marked improvements in the allylic alkylation of carbocyclic compounds.
Book Synopsis Applications of Palladum [sic] Catalyzed Asymmetric Allylic Alkylation by : Jennifer Ann Vance
Download or read book Applications of Palladum [sic] Catalyzed Asymmetric Allylic Alkylation written by Jennifer Ann Vance and published by . This book was released on 2005 with total page 656 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Development of Metal-catalyzed Asymmetric Allylic Alkylations for the Total Synthesis of Alkaloids and Other Nitrogen Containing Biologically Active Targets by : Maksim Osipov
Download or read book Development of Metal-catalyzed Asymmetric Allylic Alkylations for the Total Synthesis of Alkaloids and Other Nitrogen Containing Biologically Active Targets written by Maksim Osipov and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation deals with the development of metal-catalyzed asymmetric allylic alklyations, and their use for the synthesis of alkaloids and other nitrogen-containing biologically active compounds. The synthesis of the drug ( -- )-ranirestat is disclosed, which relies on a Pd-catalyzed asymmetric allylic alkylation (Pd-AAA) as a key step. The development and application of pyrroles and indoles as nucleophiles in the Pd-AAA is described. A Pd-catalyzed decarboxylative asymmetric alkylation approach to constructing vicinal all-carbon quaternary stereocenters is disclosed, and this methodology is used to complete the formal synthesis of several cyclotryptamine alkaloids. Finally, a catalytic asymmetric total synthesis of the alkaloid ( -- )-perophoramidine and efforts towards the alkaloid communesin B are described. Both syntheses employ a molybdenum-catalyzed asymmetric allylic alkylation as a key asymmetric step. ( -- )-Ranirestat is a potent aldose reductase inhibitor currently in phase III clinical testing for its ability to treat diabetic neuropathy. We have developed a concise, catalytic asymmetric total synthesis of ( -- )-ranirestat, which was completed in 8 steps and 14% overall yield starting from inexpensive, commercially available 2-(trichloroacetyl)pyrrole. A palladium-catalyzed asymmetric allylic alkylation (Pd-AAA) of an imidomalonate and an allylic carbonate serve as a key transformation to construct the tetrasubstituted stereocenter in the target with high yield and enantioselectivity. Protiodesilylation followed by oxidative cleavage of the allyl moiety and cyclization are used to access ( -- )-ranirestat. Nitrogen heterocycles are found in a variety of natural products and other biologically active compounds. We have demonstrated that pyrroles and indoles bearing electron-withdrawing groups are competent nucleophiles in the Pd-AAA with vinyl aziridines. The resulting alkylated products were obtained with high levels of regio-, chemo-, and enantioselectivity. Both substituted 1H-pyrroles and 1H-indoles were successfully employed to give exclusively the branched N-alkylated products. The synthetic utility of this asymmetric process was demonstrated through the elaboration of pyrrole products into bromopyrrole alkaloids longamide B, longamide B methyl ester, hanishin, agesamides A and B, and cyclooroidin. Likewise, the synthetic utility of the indole products was demonstrated by elaboration into several patented piperazinones and piperazine medicinal chemistry lead compounds. 1H-Pyrroles have also shown to serve as nucleophiles with meso electrophiles in the Pd-AAA. The products from this transformation were obtained as a single regio- and diastereomer in high yield and % ee. To demonstrate synthetic utility, a pyrrole-substituted nucleoside analogue was synthesized employing this methodology as the asymmetric step. Quaternary all-carbon stereocenters are present in many natural products and biologically active compounds. The presence of this structural element greatly complicates the asymmetric assembly of molecules due to steric congestion. The asymmetric assembly is complicated further when a second vicinal, quaternary center is present in a molecular target. We have discovered that a two-fold Pd-DAAA of an oxindole-derived dienol carbonate can be used to construct two vicinal all carbon quaternary stereocenters in a diastereo- and enantioselective fashion. To demonstrate the synthetic utility of this process, the product of this transformation was used to complete the formal syntheses of the cyclotryptamine alkaloids ( -- )-chimonanthine, (+)-calycanthine ( -- )-folicanthine, and ditryptophenaline. Mechanistic investigations have suggested that the two-fold Pd-catalyzed transformation proceeds through an unusual matched and mismatched allylation to deliver the desired product. Perophoramidine was isolated from the ascidian organism Perophora namei and displays cytotoxicity toward the HCT116 colon carcinoma cell line with an IC50 of 60 æM. The complex polycyclic cage-like core of this alkaloid makes it a challenging and interesting target for total synthesis. A catalytic asymmetric total synthesis of ( -- )-perophoramidine was developed employing a molybdenum-catalyzed asymmetric allylic alkylation between an allylic phosphate and an alkyl oxindole as an asymmetric step. This key transformation provides a chiral oxindole product in high yield and with high levels of regio-, diastereo-, and enantioselectivity. The chiral oxindole product, which contains the key quaternary stereocenter present in perophoramidine, was further elaborated to a pentacyclic imino ether using a reductive cyclization, oxidative cleavage and lactamization as key transformations. The imino ether was alkylated with allyl iodide to construct the second vicinal quaternary stereocenter providing an allyl imino ether as a single regio- and diastereomer. The allyl imino ether was converted to an aldehyde via ozonolysis, which was subjected to a reductive amination and cyclization sequence to complete ( -- )-perophoramidine.
Book Synopsis Expanding the Scope of the Palladium-catalyzed Asymmetric Allylic Alkylation Reaction and Applications Towards Alkaloid Syntheses by : Megan Brennan
Download or read book Expanding the Scope of the Palladium-catalyzed Asymmetric Allylic Alkylation Reaction and Applications Towards Alkaloid Syntheses written by Megan Brennan and published by . This book was released on 2008 with total page 460 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Palladium Catalyzed Decarboxylative Asymmetric Allylic Alkylation of Unstabilized Enolates by : Jiayi Xu
Download or read book Palladium Catalyzed Decarboxylative Asymmetric Allylic Alkylation of Unstabilized Enolates written by Jiayi Xu and published by . This book was released on 2008 with total page 1042 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Palladium-catalyzed Asymmetric Trimethylenemethane Cycloaddition by : Dustin Anthony Bringley
Download or read book Palladium-catalyzed Asymmetric Trimethylenemethane Cycloaddition written by Dustin Anthony Bringley and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Cycloadditions are among the most powerful reactions in organic chemistry due to their ability to rapidly build molecular complexity from simple, readily available precursors. In 1979, the Trost group described a novel method for the synthesis of cyclopentane rings by the in situ generation and subsequent [3+2] dipolar cycloaddition of palladium-bound trimethylenemethane (TMM). The method has proven to be a powerful approach for the synthesis of five-membered rings, including tetrahydrofurans and pyrrolidines, as well as larger rings sizes via [4+3] and [6+3] cycloaddition. In 2006, the Trost group demonstrated for the first time a general asymmetric protocol by employing phosphoramidites bearing cyclic amines as the chiral ligands. Using these ligands, highly enantioselective cycloadditions with electron-deficient olefins and imines were described. Herein, we describe the successful extension of the asymmetric methodology to include reactions with carbonyl groups and nitroalkenes, allowing for the synthesis of tetrahydrofurans and nitrocyclopentanes, respectively, with good to excellent enantioselectivity. For reactions with carbonyl groups, the development of novel C1-symmetric phosphoramidites was critical, and the optimized ligand was derived from a BINOL bearing a fused furan. The evolution of the ligand design will be discussed, beginning with the initial discovery that phosphoramidites with mono-substituted BINOL derivatives gave improved selectivity. In addition, since these phosphoramidites are chiral at phosphorus, the impact of this chirality on the TMM reaction is explored. The use of the optimized ligand allowed for reactions with both aromatic aldehydes and ketones. In addition, the asymmetric conditions did not require a Lewis acid co-catalyst, in contrast to the achiral ligands that had been previously investigated. For reactions with nitroalkenes, both [beta]-substituted and [beta], [beta]-disubstituted nitroalkenes could be employed as acceptors, where the use of the latter allowed for the synthesis of nitrocyclopentanes bearing a quaternary stereocenter. The nitrocyclopentane products were demonstrated to be versatile synthetic precursors, capable of undergoing further alkylation with excellent diastereoselectivity or converted to cyclopentylamines and cyclopentenones with little to no racemization. In one example, the asymmetric cycloaddition constitutes a formal synthesis of (+)-cephalotaxine. Finally, substituted TMM donors were explored and the use of a cyano donor was found to proceed with nearly perfect levels of selectivity and yield. Finally, the asymmetric TMM cycloaddition using a cyano-substituted donor was applied to the synthesis of ( - )-marcfortine C. Notably, the reaction proceeds in nearly quantitative yield with high diastereo- and enantioselectivity, and the resulting chiral center was used to establish all remaining stereocenters in the natural product. Additional highlights include a direct allylic oxidation of the exocyclic olefin, a diastereoselective intramolecular Michael addition, and an oxidative radical cyclization. Using this route, ( - )-marcfortine C was prepared in 16 steps and 2.4% overall yield.
Book Synopsis The Palladium Catalyzed Asymmetric Allylic Alkylation (AAA) by : Daniel Edward Patterson
Download or read book The Palladium Catalyzed Asymmetric Allylic Alkylation (AAA) written by Daniel Edward Patterson and published by . This book was released on 2000 with total page 734 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Axially Chiral Compounds by : Bin Tan
Download or read book Axially Chiral Compounds written by Bin Tan and published by John Wiley & Sons. This book was released on 2021-11-22 with total page 338 pages. Available in PDF, EPUB and Kindle. Book excerpt: Axially Chiral Compounds Explore this comprehensive and current volume summarizing the characteristics, synthesis, and applications of axial chirality Appearing widely in natural products, biologically active molecules, asymmetric chemistry, and material science, axially chiral motifs constitute the core backbones of the majority of chiral ligands and organocatalysts in asymmetric catalysis. In a new work of particular relevance to synthetic chemists, Axially Chiral Compounds: Asymmetric Synthesis and Applications delivers a clearly structured and authoritative volume covering the classification, characteristics, synthesis, and applications of axial chirality. A must read for every synthetic chemist practicing today, the book follows the development history, research status, and applications of axial chirality. An introductory chapter familiarizes the reader with foundational material before the distinguished authors describe the different classes and the synthesis of axial chiral compounds used in asymmetric synthesis. The book concludes with a focus on the applications of chiral ligands, chiral catalysts, and materials. Readers will also benefit from the inclusion of: A thorough introduction to asymmetric synthesis, including biaryls atropisomers, heterobiaryls atropisomers, and non-biaryls atropisomers Explorations of chiral allene, spiro skeletons, and natural products Practical discussions of asymmetric transformation, chiral ligands, and chiral catalysts An examination of miscellaneous applications of axially chiral compounds Perfect for organic chemists, chemists working with or on organometallics, catalytic chemists, and materials scientists, Axially Chiral Compounds: Asymmetric Synthesis and Applications will also earn a place in the libraries of natural products chemists who seek a one-stop reference for compounds exhibiting axial chirality.
Book Synopsis Palladium Catalyzed Asymmetric Allylic Alkylation and TMM Cycloaddition in Natural Product Syntheses by : Chunhui Jiang
Download or read book Palladium Catalyzed Asymmetric Allylic Alkylation and TMM Cycloaddition in Natural Product Syntheses written by Chunhui Jiang and published by . This book was released on 2004 with total page 854 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Palladium Catalysis Directed Towards the Synthesis of Natural Products by : Lara Schwartz Kallander
Download or read book Palladium Catalysis Directed Towards the Synthesis of Natural Products written by Lara Schwartz Kallander and published by . This book was released on 1998 with total page 508 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis 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 by : Jeffrey Scott Cannon
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.
Book Synopsis New Strategies for the Synthesis of Bioactive Natural and Unnatural Products Via Palladium Catalyzed Asymmetric Allylic Alkylation by : Weiping Tang
Download or read book New Strategies for the Synthesis of Bioactive Natural and Unnatural Products Via Palladium Catalyzed Asymmetric Allylic Alkylation written by Weiping Tang and published by . This book was released on 2004 with total page 496 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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