Download or read book Synthesis and Ring Opening Reactions of Oxabenzonorbornadiene Derivatives written by Rebecca Boutin and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Nucleophilic ring opening of oxabenzonorbornadiene (OBD) has been used in natural product synthesis as it enables precise creation of multiple stereocenters in a single step. The work presented in this thesis investigates how modifications to the OBD framework influences the regio- and stereochemistry of the products. The scope of the nickel catalyzed arylation of OBD was broadened by including C1-substituted substrates. Different 1,2-dihydronaphthol or naphthalene regioisomers could be obtained by varying the substituents' electronic properties. The latter chapters focus on the ring opening chemistry of OBD derivatives. Intramolecular ring opening of OBD was explored through the synthesis of OBDs with C1-tethered nucleophiles. Subsequent ring opening of these compounds yielded tricyclic and tetracyclic products. Finally, the scope of the palladium catalyzed Type 2 ring opening and the acid catalyzed Type 3 ring opening of the OBD derivative, cyclopropanated oxabenzonorbornadiene (CPOBD), was expanded to include substituted CPOBD substrates.
Download or read book Inter and Intramolecular Ring Opening Reactions of Oxabicyclic Substrates written by Christopher Wicks and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Oxabenzonorbornadiene (OBD) and derivatives thereof have become key substrates of interest within synthetic organic chemistry and natural product synthesis as they enable the formation of multiple stereocenters in a single transformation. The present work expands on previous studies to investigate various intramolecular transformations, and regiochemical implications regarding ring-opening reactions of asymmetric oxabicyclic alkenes. Acid-catalyzed intramolecular ring-opening reactions of cyclopropanated oxabenzonorbornadiene (CPOBD) derivatives were investigated to afford novel medium-sized ring systems in moderate to good yields and good to excellent regioselectivity. Similarly, a Ni catalyzed intramolecular ring-opening reaction of alkyl halide tethered OBD compounds was optimized, thus generating a naphthalene derivative in excellent yields. Lastly, iridium-catalyzed ring-opening reactions of unsymmetrical C1-substituted OBD derivatives is presented using alcohols and water as nucleophiles which allows for the selective synthesis of previously inaccessible substrates.
Download or read book Ring Forming and Ring Cleaving Reactions of Oxabenzonorbornadiene Derivatives written by Samuel Koh and published by . This book was released on 2020 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A novel intramolecular ring-opening reaction of oxabenzonorbornadienes tethered with C1-aryl halides has been disseminated. Ring-opening of these compounds was investigated using palladium and nickel catalysts to form fused tetracyclic frameworks. Conditions under palladium catalysis were found to synthesize dehydrated naphthalene products in excellent yield and selectivity. On the other hand, nickel-catalyzed protocols allowed for the selective syntheses of both 1,2-dihydronaphthalen-1-ol and naphthalene products. Following this, a novel acid-catalyzed intramolecular ring-opening is described for C1-alcohol and acid tethered cyclopropanated oxabenzonorbornadienes. A general preference for the reaction to proceed through a 'Type 3'' ring-opening over a 'Type 2' ring-opening was observed with alcohol tethers to form fused tricyclic frameworks containing a ring-expanded benzocycloheptene core. The final chapter discusses preliminary work on a nickel-catalyzed [2+2] cycloaddition between oxabenzonorbornadiene and alkynyl phosphonates. This procedure allows for the rapid synthesis of cyclobutenated phosphonate derivatives with excellent yields.
Download or read book Copper Catalyzed Asymmetric Synthesis written by Alexandre Alexakis and published by John Wiley & Sons. This book was released on 2013-12-30 with total page 467 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book reflects the increasing interest among the chemical synthetic community in the area of asymmetric copper-catalyzed reactions, and introduces readers to the latest, most significant developments in the field. The contents are organized according to reaction type and cover mechanistic and spectroscopic aspects as well as applications in the synthesis of natural products. A whole chapter is devoted to understanding how primary organometallics interact with copper to provide selective catalysts for allylic substitution and conjugate addition, both of which are treated in separate chapters. Another is devoted to the variety of substrates and experimental protocols, while an entire chapter covers the use on non-carbon nucleophiles. Other chapters deal with less-known reactions, such as carbometallation or the additions to imines and related systems, while the more established reactions cyclopropanation and aziridination as well as the use of copper (II) Lewis acids are warranted their own special chapters. Two further chapters concern the processes involved, as determined by mechanistic studies. Finally, a whole chapter is devoted to the synthetic applications. This is essential reading for researchers at academic institutions and professionals at pharmaceutical or agrochemical companies.
Download or read book Studies on the Ring opening cross Metathesis of 8 oxabicyclo 3 2 1 octene Derivatives and Its Application Towards the Synthesis of Latrunculin B written by María E. Estrella-Jiménez and published by . This book was released on 2005 with total page 388 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Asymmetric Synthesis with Chemical and Biological Methods written by Dieter Enders and published by John Wiley & Sons. This book was released on 2007-04-09 with total page 472 pages. Available in PDF, EPUB and Kindle. Book excerpt: Edited by two of the leading researchers in the field, this book provides a deep, interdisciplinary insight into stoichiometric and catalytic reactions in this continuously expanding area. A plethora of top German scientists with an international reputation covers various aspects, from classical organic chemistry to process development, and from the theoretical background to biological methods using enzymes. Throughout the focus is on the development of new synthetic methods in asymmetric synthesis, the synthesis of natural and bioactive compounds and the latest developments in both chemical and biological methods of catalysis, as well as the investigation of special technical and biotechnical aspects.
Download or read book Investigations Into the Ruthenium Catalyzed Ring Opening and Dimerization Reactions of Oxabicyclic Alkenes written by Kelsey Jack and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Transition Metal Catalyzed Ring opening Reactions of Unsymmetrical Oxabicyclic Alkenes written by Raheem Mohammed Abdul and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book From Commonly Misunderstood Organic Reactions to the Ring opening of C 1 Substituted Oxabenzonorbornadienes written by University of Guelph. Dept. of Chemistry and Biochemistry and published by . This book was released on 2009 with total page 119 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Investigating Rings written by Andrew Tigchelaar and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Rhodium Catalysed Asymmetric Ring Opening of Oxabicyclic Alkenes and Diastereoselective Ring Opening of Epoxides with Heteroatom Nucleophiles written by Keith Fagnou and published by . This book was released on 2000 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Oxabenzonorbornadienes were shown to undergo asymmetric ring opening with a variety of alcohol, phenol and activated amine nucleophiles in the presence of catalytic amounts of [Rh(COD)Cl]2 and chiral diphosphine ligands. The product dihydronaphthalenols were produced in 73-99%ee. Extension of this methodology to 'o'-halophenols required changing the rhodium source to [Rh(CO)2Cl]2. These products were applied to the synthesis of benzodihydrofurans. In order for carboxylates and unactivated amines to induce ring opening, the addition of a proton source was required. Enantioselectivities of up to 74% and 81% were observed for the amine and the carboxylate ring opened products respectively. These products were applied towards the synthesis of 1,4-dihydronaphthalenols. Vinyl Epoxides were shown to undergo diastereoselective ring opening reaction with alcohols and aromatic amine nucleophiles in the presence of catalytic amounts of [Rh(CO)2Cl]2. The 'trans '-1,2-alkoxyalcohols and aminoalcohols were produced in >80% yield and >20:1 diastereoselectivity.
Download or read book Stereoselective Synthesis of Drugs and Natural Products written by Vasyl Andrushko and published by John Wiley & Sons. This book was released on 2013-08-16 with total page 1836 pages. Available in PDF, EPUB and Kindle. Book excerpt: Brings together the best tested and proven stereoselective synthetic methods Both the chemical and pharmaceutical industries are increasingly dependent on stereoselective synthetic methods and strategies for the generation of new chiral drugs and natural products that offer specific 3-D structures. With the publication of Stereoselective Synthesis of Drugs and Natural Products, researchers can turn to this comprehensive two-volume work to guide them through all the core methods for the synthesis of chiral drugs and natural products. Stereoselective Synthesis of Drugs and Natural Products features contributions from an international team of synthetic chemists and pharmaceutical and natural product researchers. These authors have reviewed the tremendous body of literature in the field in order to compile a set of reliable, tested, and proven methods alongside step-by-step guidance. This practical resource not only explores synthetic methodology, but also reaction mechanisms and applications in medicinal chemistry and drug discovery. The publication begins with an introductory chapter covering general principles and methodologies, nomenclature, and strategies of stereoselective synthesis. Next, it is divided into three parts: Part One: General Methods and Strategies Part Two: Stereoselective Synthesis by Bond Formation including C-C bond formation C-H bond formation C-O bond formation C-N bond formation Other C-heteroatom formation and other bond formation Part Three: Methods of Analysis and Chiral Separation References in every chapter serve as a gateway to the literature in the field. With this publication as their guide, chemists involved in the stereoselective synthesis of drugs and natural products now have a single, expertly edited source for all the methods they need.
Download or read book Synthesis Characterization and Nucleophilic Ring Opening Reactions of Cyclohexyl substituted haloamines and Aziridinium Ions written by and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book New Reactions of Cyclic Oxygen Nitrogen and Sulfur Acetal Derivatives written by S. E. Mann and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis describes the development of new reactions of cyclic oxygen, nitrogen and sulfur acetal derivatives and their applications in a diverse range of synthetic organic and organometallic chemistry. Detailed herein are advances in three main areas of acetal chemistry, namely: studies towards a new methodology for the synthesis of medium ring heterocycles; the use of thioacetals as directing groups for the palladium-mediated oxidation of olefins; and multi-component reactions for the synthesis of drug-like heterocyclic compounds. A brief overview of the chemistry of cyclic acetal derivatives is given in the first chapter, followed by a chapter on each of the three areas investigated. Relevant introductory literature is reviewed at the beginning of each chapter. Firstly, the ring expansion chemistry of unsaturated cyclic oxygen, nitrogen and sulfur acetal derivatives was explored for the development of a new methodology for the synthesis of medium ring heterocycles. This methodology has thus far proved unsuccessful in the synthesis of medium rings, although several interesting and unusual transformations were observed, such as the unexpected formation of an intriguing bicyclic enaminium salt. The use of thioacetals as directing groups for the palladium-mediated oxidation of terminal olefins was also explored, leading to the evolution of a new methodology for the catalytic, regioselective formation of either vinyl or allylic acetates. Dithianes were shown to stabilise intermediates in the allylic oxidation pathway, allowing their structure elucidation and characterisation by low-temperature NMR spectroscopy and in one case X-ray crystallography. This enabled a detailed mechanistic study leading to the observation of two finely balanced, divergent reaction mechanisms. Finally, building upon previously unpublished results, a number of three and four-component reactions were investigated, giving drug-like [alpha]-aminoamides; this methodology was applied to the synthesis of some medium ring heterocycles.
Download or read book Investigation on Novel Reactions of Oxabenzonorbornadienes and Cyclopropanated Oxabenzonorbornadienes written by Angel Ho and published by . This book was released on 2020 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The present work demonstrates the first examples of carboxylic acid-tethered cyclopropanated oxabenzonorbornadienes (CPOBDs) to undergo ring-opening reactions in mild acidic conditions. Two regioisomers are formed but the reactions are highly regioselective towards type 3 ring-opened products. It was observed that substitution at the C-5 and aryl positions of CPOBD significantly hinders the ring-opening reactions leading to poor yields of ring-opened product, although high regioselectivity for the type 3 ring-opened product is still maintained. The second part of this thesis outlines a study on the regio- and stereo-chemistry of the iridium-catalyzed hydroacylation of C1-substituted OBDs with salicylaldehyde. The scope of the reaction was expanded to include various electron-donating, electron-withdrawing and bulky substituents to investigate the electronic and steric effects of the C1- substituent on the hydroacylation reaction. It was observed that the addition occurred exclusively at the less hindered, C3 position to give the corresponding adducts.
Download or read book Synthesis of Substituted Oxabenzonorbornadienes and Their Reactions written by Jamie Haner and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book I Regiospecificity of Ring Opening Reactions of Oxetanes and Epoxides with Trimethylsilyl Cyanide and Diethylaluminum Chloride written by C. Jeffrey Mullis and published by . This book was released on 1984 with total page 188 pages. Available in PDF, EPUB and Kindle. Book excerpt:
