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Author : Peter L. Johnson
Publisher :
ISBN 13 :
Total Pages : 322 pages
Book Rating : 4.:/5 (198 download)
Download or read book Palladium-catalyzed Coupling of Unsaturated Halides with Cyclic and Bicyclic Alkenes written by Peter L. Johnson and published by . This book was released on 1989 with total page 322 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author : Christine Le
Publisher :
ISBN 13 :
Total Pages : 0 pages
Book Rating : 4.:/5 (133 download)
Download or read book Rhodium-Catalyzed Asymmetric Ring Opening of Oxabicyclic Alkenes and Palladium-Catalyzed Carbon-Halogen Bond Forming Reactions written by Christine Le and published by . This book was released on 2017 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Atom-economical addition reactions to unsaturated carbonâ carbon bonds represent a powerful class of transformations in organic chemistry, since a great deal of molecular complexity can be generated from simple starting materials. Highly regio- and stereoselective processes have been made possible through the use of transition metal catalysts, alongside specialized ancillary ligands and in combination with rational substrate design. One area of research in the Lautens group involves the transition metal catalyzed asymmetric ring opening (ARO) of strained alkenes, which provides access to enantioenriched carbocyclic frameworks. Although a variety of coupling partners have been applied in this transformation, the use of soft carbon nucleophiles remains limited in scope. The first chapter describes a rhodium(I)-catalyzed ARO of meso-oxabicyclic alkenes using silyl enol ethers and ketene acetals. In analogy to the Mukaiyama aldol reaction, a novel silyl migration occurs, enabling an in situ protection of the chiral alcohols obtained. Developing new reactivity from Heck-type carbopalladation processes represents another research interest in the Lautens group. Oxidative addition into a carbonâ halogen bond constitutes the first step of nearly all palladium(0)-catalyzed cross-couplings. Conversely, reductive elimination from palladium(II) to yield an organohalide product represents a rare and often thermodynamically unfavoured process. The next two chapters address challenges in the synthesis of vinyl halides using palladium(0) catalysis via the intramolecular carbohalogenation and chlorocarbamoylation of alkynes. During our investigations, we discovered that the steric bulk of both the substrate and the phosphine ligand play an important role in promoting the desired reactivity. Mechanistic insight has been gained through combined experimental and computational studies, which implicate a palladium-catalyzed stereoisomerization in both of these transformations. Under certain conditions, we demonstrate that highly stereoselective trans-additions to alkynes can be achieved, which illustrates that specific substrate/catalyst combinations can override the inherent cis-selectivity in carbometallations. In the fourth chapter, a formal palladium(II)-catalyzed alkyne chlorocarbamoylation reaction is presented, which provides access to medicinally relevant methylene oxindole scaffolds. In contrast to the analogous protocol using palladium(0) catalysts, the reaction is initiated by an alkyne chloropalladation step, followed by intramolecular cross-coupling with a carbamoyl chloride. Experimental and computational studies provide insight into the mechanism of this reaction.
Author : P. Henry
Publisher : Springer Science & Business Media
ISBN 13 : 940099446X
Total Pages : 449 pages
Book Rating : 4.4/5 (9 download)
Download or read book Palladium Catalyzed Oxidation of Hydrocarbons written by P. Henry and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 449 pages. Available in PDF, EPUB and Kindle. Book excerpt: The field of organometallic chemistry has emerged over the last twenty-five years or so to become one of the most important areas of chemistry, and there are no signs of abatement in the intense current interest in the subject, particularly in terms of its proven and potential application in catalytic reactions involving hydrocarbons. The development of the organometallic/ catalysis area has resulted in no small way from many contributions from researchers investigating palladium systems. Even to the well-initiated, there seems a bewildering and diverse variety of organic reactions that are promoted by palladium(II) salts and complexes. Such homogeneous reactions include oxidative and nonoxidative coupling of substrates such as olefins, dienes, acetylenes, and aromatics; and various isomerization, disproportionation, hydrogenation, dehydrogenation, car bonylation and decarbonylation reactions, as well as reactions involving formation of bonds between carbon and halogen, nitrogen, sulfur, and silicon. The books by Peter M. Maitlis - The Organic Chemistry of Palladium, Volumes I, II, Academic Press, 1971 - serve to classify and identify the wide variety of reactions, and access to the vast literature is available through these volumes and more recent reviews, including those of J. Tsuji [Accounts Chem. Res. , 6, 8 (1973); Adv. in Organometal. , 17, 141 (1979)], R. F. Heck [Adv. in Catat. , 26, 323 (1977)], and ones by Henry [Accounts Chem. Res. , 6, 16 (1973); Adv. in Organometal. , 13, 363 (1975)]. F. R. Hartley's book - The Chemistry of Platinum and Palladium, App!. Sci. Pub!.
Author : Árpád Molnár
Publisher : John Wiley & Sons
ISBN 13 : 3527648305
Total Pages : 531 pages
Book Rating : 4.5/5 (276 download)
Download or read book Palladium-Catalyzed Coupling Reactions written by Árpád Molnár and published by John Wiley & Sons. This book was released on 2013-02-14 with total page 531 pages. Available in PDF, EPUB and Kindle. Book excerpt: This handbook and ready reference brings together all significant issues of practical importance in selected topics discussing recent significant achievements for interested readers in one single volume. While covering homogeneous and heterogeneous catalysis, the text is unique in focusing on such important aspects as using different reaction media, microwave techniques or catalyst recycling. It also provides a comprehensive treatment of key issues of modern-day coupling reactions having emerged and matured in recent years and emphasizes those topics that show potential for future development, such as continuous flow systems, water as a reaction medium, and catalyst immobilization, among others. With its inclusion of large-scale applications in the pharmaceutical industry, this will equally be of great interest to industrial chemists. From the contents * Palladium-Catalyzed Cross-Coupling Reactions - A General Introduction * High-turnover Heterogeneous Palladium Catalysts in Coupling Reactions: the Case of Pd Loaded on Dealuminated Y Zeolites Palladium-Catalyzed Coupling Reactions with Magnetically Separable Nanocatalysts * The Use of Ordered Porous Solids as Support Materials in Palladium-Catalyzed Cross-Coupling Reactions * Coupling Reactions Induced by Polymer-Supported Catalysts * Coupling Reactions in Ionic Liquids * Cross-Coupling Reactions in Aqueous Media * Microwave-Assisted Synthesis in C-C and C-Heteroatom Coupling Reactions * Catalyst Recycling in Palladium-Catalyzed Carbon-Carbon Coupling Reactions * Nature of the True Catalytic Species in Carbon-Carbon Coupling Reactions with * Heterogeneous Palladium Precatalysts * Coupling Reactions in Continuous Flow Systems * Large-Scale Applications of Palladium-Catalyzed Couplings in the Pharmaceutical Industry
Author : Wade H. Shafer
Publisher : Springer Science & Business Media
ISBN 13 : 1461534747
Total Pages : 421 pages
Book Rating : 4.4/5 (615 download)
Download or read book Masters Theses in the Pure and Applied Sciences written by Wade H. Shafer and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 421 pages. Available in PDF, EPUB and Kindle. Book excerpt: Masters Theses in the Pure and Applied Sciences was first conceived, published, and disseminated by the Center for Information and Numerical Data Analysis and Synthesis (CINDAS) * at Purdue University in 1957, starting its coverage of theses with the academic year 1955. Beginning with Volume 13, the printing and dissemination phases of the activity were transferred to University Microfilms/Xerox of Ann Arbor, Michigan, with the thought that such an arrangement would be more beneficial to the academic and general scientific and technical community. After five years of this joint undertaking we had concluded that it was in the interest of all con cerned if the printing and distribution of the volumes were handled by an interna tional publishing house to assure improved service and broader dissemination. Hence, starting with Volume 18, Masters Theses in the Pure and Applied Sciences has been disseminated on a worldwide basis by Plenum Publishing Cor poration of New York, and in the same year the coverage was broadened to include Canadian universities. All back issues can also be ordered from Plenum. We have reported in Volume 34 (thesis year 1989) a total of 13,377 theses titles from 26 Canadian and 184 United States universities. We are sure that this broader base for these titles reported will greatly enhance the value of this important annual reference work. While Volume 34 reports theses submitted in 1989, on occasion, certain univer sities do report theses submitted in previous years but not reported at the time.
Author : Chi Tu
Publisher :
ISBN 13 :
Total Pages : 330 pages
Book Rating : 4.:/5 (34 download)
Download or read book Palladium-catalyzed Cross-coupling of Organic Halides, Alkenes and Nucleophiles written by Chi Tu and published by . This book was released on 1993 with total page 330 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author : Jie Jack Li
Publisher : Elsevier
ISBN 13 : 9780080437057
Total Pages : 436 pages
Book Rating : 4.4/5 (37 download)
Download or read book Palladium in Heterocyclic Chemistry written by Jie Jack Li and published by Elsevier. This book was released on 2000 with total page 436 pages. Available in PDF, EPUB and Kindle. Book excerpt: For this text, Jack Li and Gordon Gribble have compiled an array of referenced examples of the use of palladium in heterocyclic chemistry.
Author : Jie Jack Li
Publisher : Gulf Professional Publishing
ISBN 13 : 0080914411
Total Pages : 1011 pages
Book Rating : 4.0/5 (89 download)
Download or read book Palladium in Heterocyclic Chemistry written by Jie Jack Li and published by Gulf Professional Publishing. This book was released on 2006-10-30 with total page 1011 pages. Available in PDF, EPUB and Kindle. Book excerpt: Palladium chemistry, despite its immaturity, has rapidly become an indispensable tool for synthetic organic chemists. Heterocycles are of paramount importance in the pharmaceutical industry and palladium chemistry is one of the most novel and efficient ways of making heterocycles. Today, palladium-catalyzed coupling is the method of choice for the synthesis of a wide range of biaryls and heterobiaryls. The number of applications of palladium chemistry to the syntheses of heterocycles has grown exponentially. These developments highlight the need for a monograph dedicated solely to the palladium chemistry in heterocycles and this book provides a comprehensive explanation of the subject. The principal aim of Palladium in Heterocyclic Chemistry is to highlight important palladium-mediated reactions of heterocycles with emphasis on the unique characteristics of individual heterocycles. 1. Palladium chemistry of heterocycles has its "idiosyncrasies" stemming from their different structural properties from the corresponding carbocyclic aryl compounds. Even activated chloroheterocycles are sufficiently reactive to undergo Pd-catalyzed reactions. As a consequence of &agr and &bgr activation of heteroaryl halides, Pd-catalyzed chemistry may take place regioselectively at the activated positions, a phenomenon rarely seen in carbocyclic aryl halides. In addition, another salient peculiarity in palladium chemistry of heterocycles is the so-called "heteroaryl Heck reaction". For instance, while intermolecular palladium-catalyzed arylations of carbocyclic arenes are rare, palladium-catalyzed arylations of azoles and many other heterocycles readily take place. Therefore, the principal aim of this book is to highlight important palladium-mediated reactions of heterocycles with emphasis on the unique characteristics of individual heterocycles. 2. A myriad of heterocycles are biologically active and therefore of paramount importance to medicinal and agricultural chemists. Many heterocycle-containing natural products (they are highlighted in boxes throughout the text) have elicited great interest from both academic and industrial research groups. Recognizing the similarities between the palladium chemistry of arenes and heteroarenes, a critical survey of the accomplishments in heterocyclic chemistry will keep readers abreast of such a fast-growing field. We also hope this book will spur more interest and inspire ideas in such an extremely useful area. This book comprises a compilation of important preparations of heteroaryl halides, boranes and stannanes for each heterocycle. The large body of data regarding palladium-mediated polymerization of heterocycles in material chemistry is not focused here; neither is coordination chemistry involving palladium and heterocycles. Many heterocycle-containing natural products (highlighted throughout the text) have elicited great interest from both academic and industrial research groups. Recognizing the similarities between the palladium chemistry of arenes and heteroarenes, a critical survey of the accomplishments in heterocyclic chemistry keeps readers abreast of this fast-growing field. It is also hoped that this book will stimulate more interest and inspire new ideas in this exciting field. - Contains the most up-to-date developments in this fast-moving field - Includes 3 new chapters - Contains material from selected well-respected authors on heterocyclic chemistry
Author : Roshan Dhungana
Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (127 download)
Download or read book Development of Nickel and Palladium-catalyzed Alkene Dicarbofunctionalization Reactions written by Roshan Dhungana and published by . This book was released on 2021 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Transition metal (TM)-catalyzed difunctionalization of alkenes with two carbon-based entities is a powerful method to construct complex molecular architectures rapidly from simple and readily available feedstock chemicals. However, the development of alkene dicarbofunctionalization became challenging due to the two major side reactions such as cross-coupling between organohalide and organometallic reagent, and Heck reaction by [beta]-H elimination from C(sp3)-M species. To avoid these complications, earlier reports in this area utilized geometrically constrained bicyclic alkenes; activated diene and styrene by stabilizing C(sp3)-M species through the formation of [pi]-allyl/[pi]-benzyl intermediates in the presence of Pd-catalyst. But when simple alkene was used where C(sp3)-M species can not be stabilized, the reaction afforded 1,1-difunctionalized product. We reasoned that the use of coordinating group in the alkene and 1st row transition metal could solve the two major issues in the development of alkene dicarbofunctionalization. During my PhD, I developed transition metal-catalyzed three-component dicarbofunctionalizaiton reactions of alkenes with the help of a coordinating group. In addition, I also developed cyclization-coupling reactions of alkenes bearing a simple functional group. In the chapter-2 of my dissertation, I focus on the development of nickel-catalyzed three-component alkene dicarbofunctionalization, which are assisted by removable coordinating groups, leading to diarylation, dialkylation, and arylbenzylation in vinyl dimethylpyridylsilane and 2-alkenylarylaldimines. These reactions successfully add aryl and alkyl electrophilic and nucleophilic coupling partners to alkenes in a highly regioselective manner. Also, the reactions exhibit a high degree of functional groups tolerance. Radical probe and control experiments are performed to provide support for the proposed mechanism. In the chapter-3 of my dissertation I focus on the development of nickel-catalyzed alkene dicarbofunctionalization using simple functional groups as a coordinating group. This section mainly describes how a simple functional group in the alkene substrate can help in stabilizing C(sp3)-M species in carrying out the desired transformation. Simple functional groups such as ketone and cyanoester have been implemented in difunctionalizing alkenes to produce [gamma],[delta] and [beta],[delta]-difunctionalized products respectively. Mechanistic investigations including deuterium labelling, crossover, radical probe, quantitative kinetic, and a Hammett plot were performed to understand and provide supports for the proposed mechanisms. In addition, in the same chapter, I also describe a palladium catalyzed two-component cyclization-coupling reaction in [alpha]-H containing alkenylamide with aryliodides. This cyclization-coupling reaction, which forms [gamma]-lactams, shows a wide substrate scope with alkenyl amide and aryliodides including the diversification of NSAIDS.
Author : Adam Gerherd). Meyer
Publisher :
ISBN 13 :
Total Pages : 360 pages
Book Rating : 4.:/5 (221 download)
Download or read book Synthesis and Palladium-catalyzed Carbonylation of Substituted Vinyl Triflates written by Adam Gerherd). Meyer and published by . This book was released on 1995 with total page 360 pages. Available in PDF, EPUB and Kindle. Book excerpt: Studies the synthesis of substituted hydraxy and amino vinyl triflates and their applicability to undergo an intramolecular palladium-catalyzed carbonylation reaction. Optically active monocyclic and bicyclic [alpha], [beta]-unsaturated [ga-lactones and the monoterpene(+) mintlactone were synthesized.
Author : Viktor V. Zhdankin
Publisher : John Wiley & Sons
ISBN 13 : 1118341309
Total Pages : 630 pages
Book Rating : 4.1/5 (183 download)
Download or read book Hypervalent Iodine Chemistry written by Viktor V. Zhdankin and published by John Wiley & Sons. This book was released on 2013-10-01 with total page 630 pages. Available in PDF, EPUB and Kindle. Book excerpt: Hypervalent Iodine Chemistry is the first comprehensive text covering all of the main aspects of the chemistry of organic and inorganic polyvalent iodine compounds, including applications in chemical research, medicine, and industry. Providing a comprehensive overview of the preparation, properties, and synthetic applications of this important class of reagents, the text is presented in the following way: The introductory chapter provides a historical background and describes the general classification of iodine compounds, nomenclature, hypervalent bonding, structural features, and the principles of reactivity of polyvalent iodine compounds. Chapter 2 gives a detailed description of the preparative methods and structural features of all known classes of organic and inorganic derivatives of polyvalent iodine. Chapter 3, the key chapter of the book, deals with the many applications of hypervalent iodine reagents in organic synthesis. Chapter 4 describes the most recent achievements in hypervalent iodine catalysis. Chapter 5 deals with recyclable polymer-supported and nonpolymeric hypervalent iodine reagents. Chapter 6 covers the "green" reactions of hypervalent iodine reagents under solvent-free conditions or in aqueous solutions. The final chapter provides an overview of the important practical applications of polyvalent iodine compounds in medicine and industry. This book is aimed at all chemists interested in iodine compounds, including academic and industrial researchers in inorganic, organic, physical, medicinal, and biological chemistry. It will be particularly useful to synthetic organic and inorganic chemists, including graduate and advanced undergraduate students. It comprehensively covers the green chemistry aspects of hypervalent iodine chemistry, making it especially useful for industrial chemists.
Author : Yasushi Nishihara
Publisher : Springer Science & Business Media
ISBN 13 : 3642323685
Total Pages : 247 pages
Book Rating : 4.6/5 (423 download)
Download or read book Applied Cross-Coupling Reactions written by Yasushi Nishihara and published by Springer Science & Business Media. This book was released on 2012-12-14 with total page 247 pages. Available in PDF, EPUB and Kindle. Book excerpt: “Applied Cross-Coupling Reactions” provides students and teachers of advanced organic chemistry with an overview of the history, mechanisms and applications of cross-coupling reactions. Since the discovery of the transition-metal-catalyzed cross-coupling reactions in 1972, numerous synthetic uses and industrial applications have been developed. The mechanistic studies of the cross-coupling reactions have disclosed that three fundamental reactions: oxidative addition, transmetalation, and reductive elimination, are involved in a catalytic cycle. Cross-coupling reactions have allowed us to produce a variety of compounds for industrial purposes, such as natural products, pharmaceuticals, liquid crystals and conjugate polymers for use in electronic devices. Indeed, the Nobel Prize for Chemistry in 2010 was awarded for work on cross-coupling reactions. In this book, the recent trends in cross-coupling reactions are also introduced from the point of view of synthesis design and catalytic activities of transition-metal catalysts.
Author : Pedro Luis Arrechea
Publisher :
ISBN 13 :
Total Pages : 253 pages
Book Rating : 4.:/5 (974 download)
Download or read book Mechanistic Studies on Palladium-catalyzed C-N Cross-coupling Reaction written by Pedro Luis Arrechea and published by . This book was released on 2016 with total page 253 pages. Available in PDF, EPUB and Kindle. Book excerpt: Mechanistic studies on the palladium catalyzed C-N bond-forming reaction were carried out to generate a more complete understanding of the catalytic cycle. To understand this reaction, several kinetic studies employing simple aryl halide and amine coupling partners were performed to elucidate unknown reaction pathways. Chapter 1. The resting state for the palladium catalyzed cross-coupling of various diarylamines and aryl halides is found to be the diphenylamido complex. Kinetic studies of the catalytic reaction are used to generate an Eyring plot. Hammett studies were performed for both the aryl halide and diarylamine coupling partners. The rates of reductive elimination for catalysts based on the biaryl ligands XPhos, CyJohnPhos, CPhos, BrettPhos, RuPhos, and SPhos were evaluated. Analogues of SPhos demonstrated that electron-donation of the lower aryl group is key to the stability of the amido complex in accordance with theoretical calculations. The methoxy substituent at the C3 position is demonstrated to retard the overall rate of reductive elimination for a RuPhos-BrettPhos hybrid ligand. These studies demonstrate that reductive elimination is likely not a problematic step for C-N cross-couplings. Chapter 2. Kinetic experiments demonstrated an inverse dependence on the concentration of both amine and aryl halide coupling partners. These observations are demonstrated to be valid for several amine classes, aryl halides, and biaryl ligands. Some work is done to demonstrate mechanistic overlap with other bidentate ligands. Based on these studies, a simplified reaction network for oxidative addition is proposed which reproduces key features of the experimental system.
Author : Steven L Suib
Publisher : Newnes
ISBN 13 : 0444538712
Total Pages : 631 pages
Book Rating : 4.4/5 (445 download)
Download or read book New and Future Developments in Catalysis written by Steven L Suib and published by Newnes. This book was released on 2013-07-17 with total page 631 pages. Available in PDF, EPUB and Kindle. Book excerpt: New and Future Developments in Catalysis is a package of seven books that compile the latest ideas concerning alternate and renewable energy sources and the role that catalysis plays in converting new renewable feedstock into biofuels and biochemicals. Both homogeneous and heterogeneous catalysts and catalytic processes will be discussed in a unified and comprehensive approach. There will be extensive cross-referencing within all volumes.The various sources of environmental pollution are the theme of this volume. The volume lists all current environmentally friendly catalytic chemical processes used for environmental remediation and critically compares their economic viability. - Offers in-depth coverage of all catalytic topics of current interest and outlines future challenges and research areas - A clear and visual description of all parameters and conditions, enabling the reader to draw conclusions for a particular case - Outlines the catalytic processes applicable to energy generation and design of green processes
Author : Andrew Anthony Martins
Publisher :
ISBN 13 : 9780494525388
Total Pages : 774 pages
Book Rating : 4.5/5 (253 download)
Download or read book Metal-catalyzed Reactions of Strained Bicyclic Alkenes written by Andrew Anthony Martins and published by . This book was released on 2009 with total page 774 pages. Available in PDF, EPUB and Kindle. Book excerpt: The strain-induced reactivity of bicyclic alkenes in the presence of transition metal catalysts has enabled a wide variety of reactions to take place. Two bicyclic systems in particular, norbornene (bicyclo[2.2.1]hept-2-ene), and bicyclic hydrazines (2,3-diazabicyclo[2.2.1]hept-5-ene) react in dramatically different ways in the presence of palladium and copper catalysts, respectively.The ability of norbornene to facilitate the palladium-catalyzed ortho C-H functionalization of aryl iodides without being incorporated into the products is the basis of the Catellani reaction, and has been developed into a powerful method for aromatic polyfunctionalization. In Chapters 1-3, several terminal coupling reactions have been incorporated into the Catellani reaction sequence: intramolecular Heck reaction, heterocycle direct arylation, and hydrogenolysis. In Chapter 1, an intramolecular Heck coupling enabled the synthesis of substituted benzochroman and benzoxepine heterocycles. In Chapter 2, the direct arylation of thiophene- and furan-based heterocycles was used to form a variety of polycyclic aromatic heterocycles; and subsequent mechanistic studies led to the proposal of an electrophilic metalation mechanism for thiophene direct arylation. In Chapter 3, an unexpected hydrogenolysis reaction in the absence of beta-hydrogens led to the synthesis of diarylmethanes and the discovery of a new arylpalladium(II) reduction mediated by benzyl halides. The mechanistic studies in Chapter 3 required the synthesis of an ortho-deuterated aniline, and to this end, a simple and cost-effective synthesis of deuterated anilines was developed in Chapter 4.Lewis acid catalysts promote the addition of nucleophiles to bicyclic hydrazines to form ring-opened chiral cyclopentenes. In Chapter 5, copper-based Lewis acids were found to facilitate an intramolecular ring opening reaction, which was combined with N-arylation to generate a variety of N'-arylaminooxazolidinones. The results of this work led to a structural revision of the intramolecular ring opening product.
Author : Liu Ye
Publisher : Open Dissertation Press
ISBN 13 : 9781361039427
Total Pages : 510 pages
Book Rating : 4.0/5 (394 download)
Download or read book PALLADIUM-CATALYZED INTRAMOLEC written by Liu Ye and published by Open Dissertation Press. This book was released on 2017-01-26 with total page 510 pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation, "Palladium-catalyzed Intramolecular Aminoalkylation of Unactivated Alkenes for Synthesis of Nitrogen-containing Heterocycles" by Liu, Ye, 葉柳, was obtained from The University of Hong Kong (Pokfulam, Hong Kong) and is being sold pursuant to Creative Commons: Attribution 3.0 Hong Kong License. The content of this dissertation has not been altered in any way. We have altered the formatting in order to facilitate the ease of printing and reading of the dissertation. All rights not granted by the above license are retained by the author. Abstract: Palladium-catalyzed carboamination (simultaneous formation of C-N and C-C bonds from an olefin) has emerged as an efficient protocol for the synthesis of diversely functionalized N-heterocycles, which are widely displayed in natural products and pharmaceuticals. Compared with the well-documented aminoarylation, aminovinylation and aminoalkynylation, analogous aminoalkylation remains a challenge. This project aims at developing innovative strategies for aminoalkylation to construct a broad array of N-containing heterocycles. An efficient and general palladium-catalyzed intramolecular aminoalkylation of alkenyl aromatic α-halo acetamides with a wide substrate scope under mild conditions has been developed, yielding diverse dihydropyrroloindole derivatives of pharmaceutical interest. Preliminary mechanistic studies suggest that the reaction involves a Pd(0)/Pd(II) catalytic cycle, initiated by oxidative addition of α-halogen of amide with Pd(0) complex. The formation of an unprecedented four-membered-ring Pd(alkyl)amido complex is also supported by ESI-MS analysis. The synthetic utility of this aminoalkylation has been demonstrated by the synthesis of bioactive compounds A, B and C. Then the aminoalkylation reaction has been expanded to the more challenging alkenyl aliphatic α-halo acetamide substrates. This transformation features no requirement for air and moisture sensitive phosphine ligands and provides a straightforward access to a variety of bicyclic pyrrolizidine derivatives. Detailed mechanism studies support the hypothesis that the formation of a four-coordinate intermediate 3-IV is crucial for the realization of this transformation. An isotopic labeling experiment indicates that the aminopalladation proceeds through syn-insertion of alkene into Pd-N bond. The application of this aminoalkylation reaction to construct bicyclic isoxazolidines from α-halo oxy-acetamides has been explored. The reaction proceeds well at room temperature for α-iodo substrates. In addition, α-bromo and α-chloro substrates are also compatible, affording the desired products in good yields with moderate diastereoselectivity. The observation of different effects from externally added phosphine ligands indicates a distinct catalytic cycle, which may involve an initial aminopalladation followed by bimetallic transmetallation or oxidative addition. This tandem cyclization may offer a novel route to natural products and bioactive compounds containing this core. Finally, the enantioselective intramolecular aminoalkylation for the construction of chiral bicyclic isoxazolidines has been attempted. After screening of a variety of reaction parameters and a series of SPINOL-based ligands, a catalytic system has been disclosed, which utilizes 7 mol% Pd(TFA)2, 20 mol% (R)-Siphos-PE, 300 mol% sodium bromide and 100 mol% sodium carbonate. The desired product can be obtained in 70% yield with 60% enantiomeric excess. A general structure-activity-relationship (SAR) for SPINOL-based ligands is obtained, which provides a platform for further modification. DOI: 10.5353/th_b5610939 Subjects: Heterocyclic compounds - Synthesis Transition metal catalysts
Author : W. H. Shafer
Publisher : Plenum Publishing Corporation
ISBN 13 : 9780306443480
Total Pages : 392 pages
Book Rating : 4.4/5 (434 download)
Download or read book Masters Theses in the Pure and Applied Sciences written by W. H. Shafer and published by Plenum Publishing Corporation. This book was released on 1992 with total page 392 pages. Available in PDF, EPUB and Kindle. Book excerpt: Masters Theses Listed by Discipline: Aerospace Engineering. Agricultural Economics, Sciences and Engineering. Architechtural Engineering and Urban Planning. Astronomy. Astrophysics. Ceramic Engineering. Communications Engineering and Computer Science. Cryogenic Engineering. Electrical Engineering. Engineering Mechanics. Engineering Physics. Engineering Science. Fuels, Combustion, and Air Pollution. General and Environmental Engineering. Geochemistry and Soil Science. Geological Sciences and Geophysical Engineering. Geology and Earth Science. Geophysics. Industrial Engineering. Marine and Ocean Engineering. Materials Science and Engineering. Mechanical Engineering and Bioengineering. Metallurgy. Meteorology and Atmospheric Science. 17 additional disciplines. Index.
