Download or read book Palladium and Electrophilic Cyclization Approaches to Carbo and Heterocyclic Compounds written by Dawei Yue and published by . This book was released on 2004 with total page 452 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this dissertation the scope and limitations of several electrophilic cyclization processes have been presented. In particular, electrophilic cyclization has been used for the synthesis of a variety of heterocycles, including benzo[b]furans, isochromenes, dihydroisoquinolines, isobenzofurans and coumestans. An unusual palladium migration has also been explored and applied to the synthesis of fluoren-9-ones. Chapter 1 describes the synthesis of 2,3-disubstituted benzo[b]furans by the palladium-catalyzed coupling and electrophilic cyclization of terminal alkynes. A highly chemoselective electrophilic cyclization has been achieved by carefully choosing the protecting group on the oxygen functionality. Various electrophiles, such as I2, Br2, PhSeCl and p-O2NC6H4SCl, can be used to introduce different functionalities into the desired cyclization products. Chapter 2 presents the synthesis of heterocycles by electrophilic cyclization reactions of acetylenic aldehydes, ketones and imines. The overall synthetic process involves the coupling of a terminal acetylene with o-iodoarenecarboxaldehydes or ketones by a palladium-catalyzed coupling reaction, followed by electrophilic cyclization with various electrophiles in the presence of proper nucleophiles. Oxygen- and nitrogen-containing heterocycles can be quickly assembled by this three component process in good to excellent yields. Chaper 3 describes the synthesis of coumestan and coumestrol by selective electrophilic cyclization, followed by palladium-catalyzed intramolecular carbonylation and lactonization. The biologically interesting coumestan system can be quickly constructed by this very efficient approach from common starting materials. The palladium-catalyzed reaction effects as both carbonylation and lactonization in one step. Chapter 4 examines the scope and synthetic utility of a 1,4-Pd through space migration. The synthesis of various fluoren-9-ones has been accomplished by the Pd-catalyzed intramolecular C-H activation of imines derived from 2-iodoaniline and biarylcarboxaldehydes. This methodology makes use of a novel 1,4-palladium migration from an aryl position to an imidoyl position to generate the key imidoyl palladium intermediate, which undergoes intramolecular arylation to produce imines of complex polycyclic compounds containing the fluoren-9-one core structure. Both electronic effects and steric effects have been investigated.
Download or read book Palladium catalyzed and Electrophilic Cyclization Approaches to Important Heterocycles and Carbocycles written by Saurabh Mehta and published by . This book was released on 2009 with total page 250 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Palladium catalyzed and Electrophilic Cyclization Approaches to Carbocycles and Heterocycles written by Shilpa Arvind Worlikar and published by . This book was released on 2008 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Palladium in Heterocyclic Chemistry written by Jie Jack Li and published by Elsevier. This book was released on 2006-10-20 with total page 662 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 the book 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 area. Contains the most up-to-date developments in this fast-moving field Includes 3 new chapters Incorporates material from selected well-respected authors on heterocyclic chemistry
Download or read book New Approaches to Heterocycles and Carbocycles written by Tuanli Yao and published by . This book was released on 2005 with total page 342 pages. Available in PDF, EPUB and Kindle. Book excerpt: The electrophilic cyclization of functionally-substituted alkynes is a very promising route to an extraordinary range of medicinally interesting, functionally-substituted heterocycles and carbocycles. For instance, a variety of substituted isocoumarins and [alpha]-pyrones are readily prepared in excellent yields under very mild reaction conditions by the reaction of o-(l-alkynyl)benzoates and (Z)-2-alken-4-ynoates with IC1,I2, PhSeCl, p-O2NC6H4SCl, and HI. This methodology accommodates various alkynyl esters and has been successfully extended to the synthesis of polycyclic aromatic and biaryl compounds. Electrophilic cyclization of o-(l-alkynyl)benzamides with IC1, I2, and NBS, affords a variety of substituted isoindolin-1-ones in good to excellent yields. In a few cases, substituted isoquinolin-1-ones were obtained as the major product instead. This methodology accommodates various alkynyl amides and functional groups, and has been successfully extended to heterocyclic starting materials. This chemistry has been successfully applied to the formal synthesis of a biologically interesting alkaloid cepharanone B.A variety of substituted polycyclic aromatics are readily prepared in good to excellent yields under very mild reaction conditions by the reaction of 2-(1-alkynyl)biphenyls with IC1, I2, NBS, and p-O2NC6H4SCl. This methodology readily accommodates various functional groups and has been successfully extended to systems containing a variety of polycyclic and heterocyclic rings. The coupling of 2-(1-alkynyl)-2-alken-1-ones with nucleophiles, either catalyzed by AuCl3 or induced by an electrophile, provides highly substituted furans in good to excellent yields under very mild reaction conditions. Various nucleophiles, including functionalized alcohols, H2O, carboxylic acids, 1,3-diketones and electron-rich arenes, and a range of cyclic and acyclic 2-(1-alkynyl)-2-alken-1-ones readily participate in these cyclizations. Iodine, NIS, and PhSeCl have proven successful as electrophiles in this process. The resulting iodine-containing furans can be readily elaborated to more complex products using known organopalladium chemistry.
Download or read book New Palladium catalyzed Approaches to Heterocycles and Carbocycles written by Qinhua Huang and published by . This book was released on 2004 with total page 629 pages. Available in PDF, EPUB and Kindle. Book excerpt: The tert-butylimines of o-(1-alkynyl)benzaldehydes and analogous pyridinecarbaldehydes have been cyclized under very mild reaction conditions in the presence of I2, ICl, PhSeCl, and p-O2NC6H4SCl to give the corresponding halogen-, selenium-, and sulfur containing disubstituted isoquinolines and naphthyridines, respectively. Monosubstituted isoquinolines and naphthyridines have been synthesized by the metal-catalyzed ring closure of these same iminoalkynes. The Pd(II)-catalyzed cyclization of 2-(1-alkynyl)arylaldimines in the presence of various alkenes provides an efficient way to synthesize a variety of 4-(1-alkenyl)-3-arylisoquinolines in moderate to excellent yields. The introduction of an ortho-methoxy group on the arylaldimine promotes the Pd-catalyzed cyclization and stabilizes the resulting Pd(II) intermediate, improving the yields of the isoquinoline products. Highly substituted naphthalenes have been synthesized by the palladium-catalyzed annulation of a variety of internal alkynes, in which two new carbon-carbon bonds are formed in a single step under relatively mild reaction conditions. This method has also been used to synthesize carbazoles, although a higher reaction temperature is necessary. This method accommodates a variety of functional groups and affords the anticipated highly substituted naphthalenes and carbazoles in good to excellent yields. Novel palladium migration/arylation methodology for the synthesis of complex fused polycycles has been developed, in which one or more sequential Pd-catalyzed intramolecular migration processes involving C-H activation are employed. The chemistry works best with electron-rich aromatics, which is in agreement with the idea that these palladium-catalyzed C-H activation reactions parallel electrophilic aromatic substitution. A relatively efficient synthesis of cyclopropanes has been developed using palladium-catalyzed C-H activation chemistry, in which two new carbon-carbon bonds are formed in a single step. This method involves the palladium-catalyzed activation of relatively unreactive C-H bonds, and provides a very efficient way to synthesize cyclopropapyrrolo[1,2-a]indoles, analogues of the mitomycin antibiotics.
Download or read book Palladium catalyzed Approaches to Carbo and Heterocyclic Compounds written by Steve Vencil Gagnier and published by . This book was released on 2001 with total page 530 pages. Available in PDF, EPUB and Kindle. Book excerpt: In order to achieve quinoline product, this annulation process needs to proceed through a 6-endo ring closure. However, this process is in competition with the more favorable 5-exo ring closure, which leads to an isoindole system. While the yields and generality for the synthesis of quinolines are only moderate, the optimization results have proven to be interesting from a mechanistic point of view. Chapter 4 concerns the synthesis of [alpha], [beta]-unsaturated ketones from the corresponding enol silyl ethers using a catalytic palladium(II) strategy. This palladium(II) procedure is performed using catalytic amounts of Pd(OAC)2 in DMSO at room temperature and uses 02 as an efficient reoxidant.
Download or read book Palladium Assisted Synthesis of Heterocycles written by Navjeet Kaur and published by CRC Press. This book was released on 2019-05-01 with total page 432 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is a compilation of the recent applications of palladium catalysts in organic synthesis. The book demonstrates that it is a highly dynamic research field. This methodology has emerged as a powerful tool for the efficient and chemoselective synthesis of heterocyclic molecules. In the past few years, several strategies have been pointed out to pursue more efficient, sustainable, and environment friendly chemical processes. Among those strategies, catalysis and the design of new processes that avoid the use of toxic reagents have been the focus of intense research.
Download or read book Palladium and Nickel Catalyzed Transformations Forming Functionalized Heterocycles written by Hyung Yoon and published by Springer Nature. This book was released on 2020-09-02 with total page 236 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents Pd- and Ni-catalyzed transformations generating functionalized heterocycles. Transition metal catalysis is at the forefront of synthetic organic chemistry since it offers new and powerful methods to forge carbon–carbon bonds in high atom- and step-economy. In Chapter 1, the author describes a Pd- and Ni-catalyzed cycloisomerization of aryl iodides to alkyl iodides, known as carboiodination. In the context of the Pd-catalyzed variant, the chapter explores the production of enantioenriched carboxamides through diastereoselective Pd-catalyzed carboiodination. It then discusses Ni-catalyzed reactions to generate oxindoles and an enantioselective variant employing a dual ligand system. Chapter 2 introduces readers to a Pd-catalyzed diastereoselective anion-capture cascade. It also examines diastereoselective Pd-catalyzed aryl cyanation to synthesize alkyl nitriles, a method that generates high yields of borylated chromans as a single diastereomer, and highlights its synthetic utility. Lastly, Chapter 3 presents a Pd-catalyzed domino process harnessing carbopalladation, C–H activation and π-system insertion (benzynes and alkynes) to generate spirocycles. It also describes the mechanistic studies performed on these reactions.
Download or read book New Palladium catalyzed Approaches to Heterocycles and Carbocycles written by Guangxiu Dai and published by . This book was released on 2003 with total page 714 pages. Available in PDF, EPUB and Kindle. Book excerpt: A wide variety of 3,4-disubstituted isoquinolines containing an aryl, allylic, benzylic, alkynyl and vinylic group at the 4 position have been prepared via cross-coupling of 2-(1-alkynyl)benzaldimines with organic halides in the presence of a palladium catalyst. The best results are obtained by employing 5 mol % Pd(PPh3)4, 5 equiv of K2CO3 in DMF at 100°C. The electronic effect of the imine substrates and organic halides on the yields has been discussed. 3-Substituted 4-aroylisoquinolines have been prepared in high yields via carbonylative cross-coupling of 2-(1-alkynyl)benzaldimines with aromatic iodides or aroyl chlorides in the presence of a palladium catalyst under 1 atm of CO pressure. Imine substrates having an aryl, vinylic or alkyl substituent on the distal end of the triple bond all undergo this palladium-catalyzed carbonylative cross-coupling cyclization in high yields. The palladium(II)-catalyzed oxidative carbonylation of 2-(1-alkynyl)benzaldimines for synthesis of the corresponding isoquinoline-4-carboxylates has been studied and the optimal reaction conditions have been investigated. Although this methodology study has not provided an efficient route to synthesize methyl 3-substituted isoquinoline-4-carboxylates in synthetically useful yields, it provides an insight into the nature of the palladium-catalyzed cyclization reactions promoted by organopalladium intermediates. A novel intramolecular alkyl-to-aryl palladium rearrangement has been observed by trapping the arylpalladium intermediate with an olefin by a Heck reaction. The reaction conditions have been optimized and the reaction scope has been extensively studied. In all of the successful examples, migration products were isolated exclusively. In addition, this alkyl-to-aryl palladium migration can be controlled by simply modifying the reaction conditions.
Download or read book Au Catalyzed Synthesis and Functionalization of Heterocycles written by Marco Bandini and published by Springer. This book was released on 2016-07-01 with total page 294 pages. Available in PDF, EPUB and Kindle. Book excerpt: The series Topics in Heterocyclic Chemistry presents critical reviews on present and future trends in the research of heterocyclic compounds. Overall the scope is to cover topics dealing with all areas within heterocyclic chemistry, both experimental and theoretical, of interest to the general heterocyclic chemistry community. The series consists of topic related volumes edited by renowned editors with contributions of experts in the field. All chapters from Topics in Heterocyclic Chemistry are published Online First with an individual DOI. In references, Topics in Heterocyclic Chemistry is abbreviated as Top Heterocycl Chem and cited as a journal
Download or read book Dissertation Abstracts International written by and published by . This book was released on 2008 with total page 906 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Heterocyclic Compounds written by Kristian Nylund and published by . This book was released on 2010 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Heterocyclic compounds are organic compounds containing at least one atom of carbon, and at least one element other than carbon, such as sulphur, oxygen or nitrogen within a ring structure. These structures may comprise either simple aromatic rings or non-aromatic rings. Some examples are pyridine (C5H5N), pyrimidine (C4H4N2) and dioxane (C4H8O2). Many heterocyclic compounds, including some amines, are carcinogenic. This book details the proposed mechanisms of Gewald-like reactions and the wide scope of substituted 2-aminothiophenes for real life applications. Literary information about synthesis methods, structure, physical-chemical and biological properties is summarised, and also information about conversion of adamantyl-1 and adamantyl-2 imidazole and benzimidazole derivatives is given. In addition, 3-acetylindole derivatives have been in the centre of attention of researchers over many years due to the high practical value of these compounds. This book presents a survey of the literature on 3-acetylindoles chemistry and provides useful and up-to-date data for medicinal chemists.
Download or read book Advances in Heterocyclic Chemistry written by and published by Academic Press. This book was released on 2018-05-21 with total page 276 pages. Available in PDF, EPUB and Kindle. Book excerpt: Advances in Heterocyclic Chemistry, Volume 126, is the definitive series in the field, one that is of great importance to organic chemists, polymer chemists and many biological scientists. Because biology and organic chemistry increasingly intersect, the associated nomenclature is used more frequently in explanations. Updates to this release include sections on The Literature of Heterocyclic Chemistry, Part XVI, 2016, The preparation and properties of heteroarylazulenes and hetero-fused azulenes, Recent developments in pyrazole chemistry, Yne, Ene-Yne Synthetic Approaches to Heterocycles, Appel Salt and Heterocycles: A review of Thirty Years of 4,5-Dichloro-1,2,3-dithiazolium Chloride Chemistry, and more. Written by established authorities in the field, this comprehensive review combines descriptive synthetic chemistry and mechanistic insight to yield an understanding on how chemistry drives the preparation and useful properties of heterocyclic compounds. Considered the definitive serial in the field of heterocyclic chemistry Serves as the go-to reference for organic chemists, polymer chemists and many biological scientists Provides timely, comprehensive reviews written by established authorities in the field Combines descriptive synthetic chemistry and mechanistic insight to enhance understanding on how chemistry drives the preparation and useful properties of heterocyclic compounds
Download or read book Heterocycles written by B. P. Nandeshwarappa and published by . This book was released on 2020-06 with total page 202 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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.
Download or read book Modern Aryne Chemistry written by Akkattu T. Biju and published by John Wiley & Sons. This book was released on 2021-08-23 with total page 530 pages. Available in PDF, EPUB and Kindle. Book excerpt: A groundbreaking book to offer a a comprehensive account of important reactions involving arynes Modern Aryne Chemistry is the first book on the market to offer a conceptual framework to the reactions related to arynes. It also provides a systematic introduction to the cycloaddition reactions, insertion reactions and transition-metal-catalyzed transformations of arynes. The author, a noted expert on the topic, highlights a novel strategy for carbon-carbon and carbon-heteroatom bond construction using arynes. The book reveiws the recent use of aryne chemistry for the development of new multicomponent reactions. New advances in this area has shown rapid emergence of a new class of reactions classified under rearrangement reactions. The author also includes information on aryne methods that have been employed for the synthesis of several natural products. The simplicity and sophistication of the synthetic strategy using arynes can serve as a springboard for organic chemists to explore new possibilities and imagine applications of the concept of arynes. This important book: Presents a one-of-kind comprehensive guide to arynes reactions Offers a proven approach to the synthesis of natural product and polymers Reviews the most recent developments in the carbon-carbon and carbon-heteroatom bond-forming reactions involving arynes Written for organic, pharmaceutical, medicinal, natural products, and catalytic Chemists, Modern Aryne Chemistry offers a comprehensive review of the fundamentals of reactions related to arynes and the most recent developments in the field.
