Download or read book Radical and Palladium Mediated Cyclisations for the Synthesis of Heterocyclic Ring Systems written by William Kofie and published by . This book was released on 2003 with total page 209 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Free Radical Synthesis and Functionalization of Heterocycles written by Yannick Landais and published by Springer. This book was released on 2018-05-03 with total page 356 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume describes the recent developments in the free-radical mediated synthesis and elaboration of heterocycles. The first chapter, dealing with radical cascade processes illustrates the power and the beauty of radical chemistry with some striking examples of total synthesis of complex natural heterocycles. As organic chemists strive towards sustainability, radical chemistry has recently seen major advances and efforts in this direction, including C-H activation of arenes and unactivated alkyl groups. Photochemical activation, for a long time the preferred mode of activation in radical chemistry has also seen an unexpected revival with the advent of visible light metal- and organocatalyzed photoredox processes. A survey of these emerging areas is provided along with the concepts at the origin of these developments. The venerable Minisci reaction allows for direct access to functionalized heterocycles. This process has lately seen an interesting renaissance and is discussed in this volume. Addition of heteroatom-centered radicals onto unsaturated systems constitutes another powerful method to construct heterocycles. Examples of such a strategy are proposed along with the formation of various heterocycles relying on homolytic substitution at sulfur, phosphorus and selenium. Additionally free-radical functionalization of reactive functional groups including isonitriles, isothiocyanates and related unsaturated systems which offer a straightforward route towards useful aromatic and non-aromatic heterocycles are discussed. Finally, as metals are able to trigger single electron transfer both in reductive and oxidative modes this provides another possibility for the synthesis of heterocycles. Significant research efforts have focused on the use of samarium, copper and other metals to access a broad variety of heterocycles in a single pot process, starting from readily available raw material. Examples and mechanistic insights are discussed by experts in this area.

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 660 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

Download or read book Advances in Transition Metal Mediated Heterocyclic Synthesis written by Daniel Sole and published by Academic Press. This book was released on 2018-05-17 with total page 368 pages. Available in PDF, EPUB and Kindle. Book excerpt: Advances in Transition-Metal Mediated Heterocyclic Synthesis provides an overview of recent catalytic reactions involving transition metals to produce heterocyclic compounds. The book is organized according to the type of transformation used to achieve the synthesis of the heterocyclic systems (mainly aza- and oxa-heterocycles). As such, it covers recent applications on the synthesis of heterocycles, also describing the details of the novel transformations in a didactic manner to motivate readers in search of new catalytic processes. The editors have included state-of-the-art strategies, including transition-metal reactions involving unsaturated systems (reactions of allenes, new gold(I)-catalyzed reactions, and Prins reaction). Chapters highlight the versatility of organopalladium chemistry dealing with carbonylative transformations, C-H activation reactions, coupling processes, and the control of the ambiphilic character of organopalladium species. Finally, the book discusses new reactions leading to heterocycles based on C-H activation processes catalyzed by other metals (Rh, Ru, Co). Written by an outstanding team of authors who are leading experts in organometallic chemistry and organic synthesis, this book is a valuable resource not only for chemists mainly focused on synthesis, but also for those interested in reaction mechanisms involving transition metals. Helpfully organized by transformation type to stimulate the search for new synthetic processes Completely illustrated and written by global experts Includes thoughtfully selected strategies chosen by the editors to exemplify the state-of-the-art of the subject, including transition-metal reactions involving unsaturated systems, organopalladium chemistry, and metal-catalyzed C-H activation

Download or read book Synthetic Endeavours in Nitrogen Heterocycles written by Charles Hamilton Heath and published by . This book was released on 2011 with total page 316 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis describes our synthetic endeavours in nitrogen containing heterocyclic compounds. The work included several key themes including the pursuit of biologically active compounds, the development of elegant and environmentally benign procedures including domino reactions. The use of palladium mediated transformations in organic synthesis, the construction of new unknown ring systems and the structural elucidation of heterocyclic compounds including the structural elucidation of natural products by synthesis have also been explored. Chapter 2 describes our synthetic investigations of the 3-benzazepines I and azepino[4,5-b]indoles II. Through the use of the palladium catalysed Tsuji-Trost reaction followed by a Heck reaction we were able to devise a synthetic approach to access these N-heterocycles. We were able to synthesize simple derivatives of both I and II in addition to more complex compounds featuring additional fused rings by including the use of different cyclic and acyclic allylic substrates for the Tsuji-Trost reaction. After the development of the single step Tsuji-Trost/Heck synthetic protocols for these compounds we successfully combined these two reactions into a single pot domino reaction. In addition to Tsuji-Trost/Heck domino reactions we have also developed a Heck/carbopalladation domino reaction for the synthesis of an azepino[3,4,5-hi]benz[b]indolizine derivative. Chapter 3 describes our attempts to synthesize the natural product arboflorine. We initially began with attempts to elaborate the azepino[4,5-b]indoles synthesized in Chapter 2 to provide arboflorine, however this did not prove fruitful. In the course of this investigation we discovered a novel rearrangement of an azepino[4,5-b]indole to give the peroxide IV which became the topic of Chapter 4. We attempted to further elaborate other known azepino[4,5-b]indoles via a variety of methods including inter and intramolecular Heck reactions, radical chain reactions and functionalization via an iminium salt. These attempts were also unsuccessful. Finally we chose to modify the synthesis of a simpler, related tetracycle for the synthesis of arboflorine, developed by Bosch and Passarella. Following their general synthetic strategy we were able to synthesize a key nitrile intermediate to the synthesis of arboflorine. The cyclization of this nitrile was attempted but was not successful under a series of reaction conditions. Chapter 4 describes the structural elucidation of the peroxide IV. A possible mechanistic explanation for the formation of the peroxide is given and this is discussed in the context of relevant literature examples. The formation of the peroxide IV led to our increased interest in the general reactivity of the azepino[4,5-b]indoles and several simple reactions were carried out in the hope of discovering further novel rearrangements.

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 482 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 Cyclization Reactions written by C. Thebtaranonth and published by CRC Press. This book was released on 1993-05-01 with total page 392 pages. Available in PDF, EPUB and Kindle. Book excerpt: Cyclization Reactions provides a quick update of the latest advances in cyclization reactions. It covers the basic principles of cyclization chemistry, emphasizing practical applications. Chapters are organized according to the different cyclization intermediates-cationic, radical, anionic, and metal complex intermediates. The last chapter covers macrolactonization, vicinal tricarbonal, and Bergman (enediyne) reactions, which are of particular interest today. More than 2,600 structures illustrate key concepts throughout the book. Various cyclizations are organized into mechanistic groups to help researchers choose and change between methods when searching for maximum efficiency in synthesis. Critical coverage of the literature up to 1992 is provided. Cyclization Reactions is essential reading for anyone involved in the synthesis of ring compounds or who is seeking a rapid overview of the field. Newcomers as well as experienced researchers will benefit from this book. It also is excellent reference material for students at the advanced undergraduate and graduate levels.

Download or read book Transition Metal Catalyzed Carbonylative Synthesis of Heterocycles written by Xiao-Feng Wu and published by Springer. This book was released on 2015-12-14 with total page 176 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 Development of New Radical Cascades and Multi Component Reactions written by Marie-Helene Larraufie and published by Springer Science & Business Media. This book was released on 2013-12-16 with total page 340 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this dissertation, Marie-Hélène Larraufie develops original radical and pallado-catalyzed methodologies to enable the synthesis of several classes of bioactive nitrogen-containing heterocycles. New radical cascades employing the N-acylcyanamide moiety offer straightforward routes to quinazolinones and guanidines, as well as new insights into the mechanism of homolytic aromatic substitutions. In parallel, Larraufie expands the scope of visible light photoredox catalysis to the ring opening of epoxides and aziridines, thus providing new sustainable alternatives for the generation of radicals. Furthermore, in a collaborative effort with the Catellani group, the author investigates dual palladium/norbornene catalysis. First, she develops a C-amination coupling variant of the Catellani reaction with unprotected amines which provides an expeditious route to phenanthridines. Then, she examines the influence of the chelating effect on Pd(IV) intermediates reactivity with the help of experimental studies and DFT calculations. The work in this thesis has resulted in numerous publications in high impact journals.The clarity and depth of the experimental section will be useful for students and researchers working in this field.

Download or read book Palladium Catalyzed Oxidative Cascade Cyclizations Via C N C C Formation for Synthesis of Nitrogen Heterocycles written by Wei Du and published by . This book was released on 2017-01-27 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation, "Palladium-catalyzed oxidative cascade cyclizations via C-N/C-C formation for synthesis of nitrogen heterocycles" by Wei, Du, 杜玮, 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: Abstract of thesis entitled PALLADIUM-CATALYZED OXIDATIVE CASCADE CYCLIZATIONS VIA C-N/C-C FORMATION FOR SYNTHESIS OF NITROGEN HETEROCYCLES submitted by Du Wei for the Degree of Doctor of Philosophy at The University of Hong Kong in May 2014 Pd(II)-catalyzed oxidative amination of alkenes is a versatile method to construct N-containing heterocycles which are found in many biologically active synthetic targets, including natural products and pharmaceuticals. Considering the efficiency of the cascade reaction, we have employed this protocol to synthesize nitrogen heterocycles (including chiral ones) via Pd(II)-catalyzed C-N/C-C bond formation. We have developed a highly efficient enantioselective method for oxidative cascade cyclization of acrylamides tethered alkene using Pd(TFA) /diPh-pyrox as catalyst under a mild aerobic condition (Scheme 1). A series of pyrrolizidine derivatives, such as 2.4a, 2.2h, and 2.2n, have been synthesized in good yields and excellent enantioselectivity. The mechanism study has indicated that the cyclization reaction proceeded through both trans-/cis-aminopalladation (AP) with a ratio of ca. 3:1 (Scheme 2). Besides, we have found that some factors, including the counterions of Pd(II) complexes, the electronic density of the isolated double bond and the steric bulkiness of ligands, affect the stereochemical selectivity in the aminopalladation step. This study has important implications for designing new catalyst systems for enantioselective Pd-catalyzed oxidative amination reactions. We have also disclosed the first enantioselective Pd(II)-catalyzed oxidative aminoarylation reaction (Scheme 3). The reactions were carried out with Pd(OAc) /β-ICD as catalyst to synthesize indoline derivatives, such as 3.2a, 3.2b and 3.2i, in moderate to good yields with moderate enantioselectivity. Base on previous successful cascade reactions of aminopalladation/C(sp )-H functionalization, we have developed a palladium (II)-catalyzed oxidative cascade aminoalkylation via aminopalladation/C(sp )-H activation for divergent synthesis of three-membered-ring (i.e. 4.2ag, 4.2an and 4.2ar) or five-membered-ring (i.e. 4.3aa, 4.3ad and 4.3bs) fused indolines (Scheme 4). The benzylic C-H and the C-H at -position of anilides can be selectively activated under different reaction conditions. 3 This is the first example of palladium catalyzed C(sp )-H activation without employment of prefunctionalized reagents (halogenated or boron-containing reagents) and directing groups, representing a green and economic protocol for construction of N-containing heterocycles. Scheme 1 Scheme 2 Scheme 3 Scheme 4 DOI: 10.5353/th_b5312312 Subjects: Heterocyclic compounds - Synthesis Organopalladium compounds

Download or read book Progress in Heterocyclic Chemistry written by Gordon Gribble and published by Elsevier. This book was released on 2004-11-26 with total page 485 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is the sixteenth annual volume of Progress in Heterocyclic Chemistry, and covers the literature published during 2003 on most of the important heterocyclic ring systems. This volume opens with two specialized reviews. The first covers 'Lamellarins: Isolation, activity and synthesis' a significant group of biologically active marine alkaloids and the second discusses 'Radical Additions to Pyridines, Quinolines and Isoquinolines'. The remaining chapters examine the recent literature on the common heterocycles in order of increasing ring size and the heteroatoms present.

Download or read book Noble Metal Noble Value Ru Rh Pd catalyzed Heterocycle Synthesis written by Xiao-feng Wu and published by World Scientific. This book was released on 2016-06-24 with total page 390 pages. Available in PDF, EPUB and Kindle. Book excerpt: Heterocyclic chemistry constitutes the largest branch of chemistry, covering almost two-thirds of literature in the field. In addition, around 90% of naturally-occurring molecules have heterocycles as their core structure. Therefore, as a central part of organic chemistry, the discovery of new methodologies in synthesizing heterocyclic compounds is essential to their continued application and development. Transition metal catalysts offer a low cost and often low toxicity pathway for heterocycles synthesis, while the use of noble metals represents an alternative form of experimentation which is discussed in the book.Noble Metals, Noble Value provides the first comprehensive analysis of the applications of the noble metals of ruthenium (Ru), rhodium (Rh) and palladium (Pd) catalysts in heterocycles synthesis. Pairs of chapters are dedicated to summarizing each of the metals when applied to either five- or six-membered heterocyclic syntheses. An introduction to the importance of heterocycles and possible procedures for the preparation of heterocyclic compounds is also given.With up to date research and findings, this review is excellently suited to academics and professionals in the field of chemistry, with a particular focus on the specialities of biological, catalytic and organic chemistry.

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.

Download or read book Transition Metal Catalyzed Heterocycle Synthesis via C H Activation written by Xiao-Feng Wu and published by John Wiley & Sons. This book was released on 2015-12-22 with total page 600 pages. Available in PDF, EPUB and Kindle. Book excerpt: Reflecting the tremendous growth of this hot topic in recent years, this book covers C-H activation with a focus on heterocycle synthesis. As such, the text provides general mechanistic aspects and gives a comprehensive overview of catalytic reactions in the presence of palladium, rhodium, ruthenium, copper, iron, cobalt, and iridium. The chapters are organized according to the transition metal used and sub-divided by type of heterocycle formed to enable quick access to the synthetic route needed. Chapters on carbonylative synthesis of heterocycles and the application of C-H activation methodology to the synthesis of natural products are also included. Written by an outstanding team of authors, this is a valuable reference for researchers in academia and industry working in the field of organic synthesis, catalysis, natural product synthesis, pharmaceutical chemistry, and crop protection.

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 Alkynes in Cycloadditions written by Irina A. Maretina and published by John Wiley & Sons. This book was released on 2013-10-08 with total page 357 pages. Available in PDF, EPUB and Kindle. Book excerpt: Acetylene systems present a new route to cyclic compounds as an alternative to more traditional methods employed in classical organic chemistry. The synthesis of cyclic structures based on acetylene systems has important applications in the formation of nanostructures, naturally occurring compounds and chemosensory materials for the design of nonlinear optics, electronic and photonic devices. Alkynes in Cycloadditions presents a modern review of regioselective synthesis of aromatic and non-aromatic carbocyclic and heterocyclic ring systems based primarily on [2+2+2] and [4+2] cycloadditions, and other reactions of acetylenic units including enediynes and enyne-allenes. Topics covered include: New strategies for the formation of aromatic and polynuclear hydrocarbons based on (Z)-hex-3-en-1,5-diyne and (Z)-hepta-1,2,4-triene-6-yne blocks. One-step synthesis of benzene derivatives, β-substituted naphthalenes and acenes by the cycloaromatization of enediynes and enyne-allenes by Bergman, Myers-Saito and Shmittel. Mechanisms of cycloaromatization resulting in the formation of fulvene and indene systems. Heterocyclization involving enyne-carbodiimides. New achievements in classical cycloaddition reactions such as the Diels-Alder condensation with acetylenic dienophiles and [2+2] cycloadditions with acetylene components Alkynes in Cycloadditions presents a comprehensive summary of the literature on methods for the synthesis of ring systems from acetylenes for academic researchers working in the fields of organic synthesis, physical organic chemistry, organometallic chemistry, catalysis, materials science, nanomaterials and biochemistry.

Download or read book Progress in Heterocyclic Chemistry written by Clementina M.M. Santos and published by Elsevier Inc. Chapters. This book was released on 2013-09-06 with total page 64 pages. Available in PDF, EPUB and Kindle. Book excerpt: This review covers work published in the calendar year 2012. Novel reaction chemistry and new ring synthetic methods for pyrans, [1]benzopyrans, dihydro[1]benzopyrans (chromenes, chromans), [2]benzopyrans, dihydro[2]benzopyrans (isochromenes, isochromans), pyranones, coumarins, chromones, xanthenes, xanthones, thiopyrans, dioxins, dioxanes, trioxanes, tetraoxanes, dithianes, trithianes, and oxathianes are reviewed.