Download or read book Preparation and Characterization of Novel 2 boron Substituted 1 3 dienes and Their Subsequent Cationic Rhodium catalyzed Diels Alder Chemistry written by John M. Solano and published by . This book was released on 2007 with total page 122 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Synthesis of 2 boron Substituted 1 3 dienes and Their Diels Alder Suzuki Cross Coupling Reactions written by Liqiong Wang and published by . This book was released on 2012 with total page 180 pages. Available in PDF, EPUB and Kindle. Book excerpt: Clerodane diterpenoids represent a large group of secondary metabolites which are distributed widely in nature. Over a thousand members have been isolated to date, many of which possess interesting biological activities: antifeedant, antitumor, antifungal, antibiotic, anti-peptic ulcer and so on. Although synthetic approaches to the transclerodanes abound, cis-clerodane syntheses are rare. The long term objective of this research is to make highly reactive dienes which would undergo Diels-Alder (D-A) reactions with sterically crowded dienophiles to construct cis-clerodane compounds. In previous work, 2-boron-1,3-dienes had shown a high propensity toward self D-A dimerization. Different strategies were tried to prepare dienes without dimerization and seven boron substituted dienes were prepared in good yields. The tri-coordinated boron dienes are less stable than the tetra-coordinated dienes because the boron atom is stabilized by donating electron pairs or groups in the latter type. The reactivity of these boron substituted dienes (2-diethanolaminoborate-1,3-butadiene) in D-A and Suzuki cross coupling reactions were tested and evaluated. Testing concluded that in D-A reactions high yields (> 90%) were found in the reactions of boron substituted 1,3-dienes and N-phenyl maleimide at room temperature or lower. The fastest diene (2-diethanolaminoborate-1,3-butadiene) reacted with a t[subscript 1/2] less than 4 minutes at -10 °C. The 2-diethanolaminoborate-1,3-butadiene has a high HOMO energy compared to its BF3 diene counterpart which accelerates its D-A reactions. High regioselectivities (16:1) were found in the D-A reactions of unsymmetrical dienophiles and 2-diethanolaminoborate-1,3-butadiene. Both high yields and regioselectivities were achieved in Suzuki cross coupling reactions of the resulting boron substituted D-A cycloadducts. Using this methodology, 2-diethanolaminoborate-1,3-butadiene is a promising precursor in providing a potential tool to asymmetric synthesis. Three boron substituted dienes reacted with n-phenylmaleimide very quickly, from seconds to 2 hours. All three dienes are stable at 0°C for more than 2 years. The research also revealed that 4 dienes can be used in tandem D-A/Suzuki cross coupling reactions. High yields and good selectivities were obtained. The possible mechanism of tandem reactions showed that Pd(II) acts as a Lewis acid catalyst to catalyze the D-A reaction between boron substituted dienes and dienophiles followed by Suzuki cross coupling reactions. A possible unstable novel intermediate, a palladium substituted diene, was observed in the reaction by NMR.
Download or read book Preparation and Diels Alder cross coupling reactions of a 2 diethanolaminoboron substituted 1 3 diene written by and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Chemical Abstracts written by and published by . This book was released on with total page 2762 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 General Methods for Preparation and Lewis acid Catalyzed Diels Alder Cycloaddition Reaction of 2 aza 1 3 dienes written by Yuching Ho and published by . This book was released on 1988 with total page 236 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Olefin Polymerization written by Walter Kaminsky and published by Wiley-VCH. This book was released on 2006-08-18 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: With an enormous velocity, olefin polymerization has expanded to one of the most significant fields in polymers since the first industrial use about 50 years ago. In 2005, 100 million tons of polyolefins were produced - the biggest part was catalyzed by metallorganic compounds. The Hamburg Macromolecular Symposium 2005 with the title "Olefin Polymerization" involved topics such as new catalysts and cocatalysts, kinetics, mechanism and polymer reaction engineering, synthesis of special polymers, and characterization of polyolefins. The conference combined scientists from different disciplines to discuss latest research results of polymers and to offer each other the possibility of cooperation. This is reflected in this volume, which contains invited lectures and selected posters presented at the symposium.
Download or read book Dienes in the Diels Alder Reaction written by Francesco Fringuelli and published by Wiley-Interscience. This book was released on 1990-05-31 with total page 376 pages. Available in PDF, EPUB and Kindle. Book excerpt: Dealing with the intermolecular Diels-Alder reaction, this book focuses on one of the reactants - the diene. Following an examination of the fundamental principles of the reaction are descriptions of the salient features of the different classes of dienes.
Download or read book Intramolecular Diels Alder and Alder Ene Reactions written by Douglass F. Taber and published by . This book was released on 2014-01-15 with total page 114 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Domino Reactions in Organic Synthesis written by Lutz F. Tietze and published by John Wiley & Sons. This book was released on 2006-12-13 with total page 631 pages. Available in PDF, EPUB and Kindle. Book excerpt: Domino reactions enable you to build complex structures in one-pot reactions without the need to isolate intermediates- a dream comes true. In this book, the well-respected expert, Professor Lutz Tietze, summarizes the possibilities of this reaction type - an approach for an efficiant, economically benificial and ecological benign synthesis. A definite must for every organic chemist.
Download or read book A Deeper Understanding of the Diels Alder Reaction written by William James Lording and published by . This book was released on 2010 with total page 550 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Diels-Alder reaction was discovered in 1928 and has become the most efficient and practical method for the synthesis of six-membered carbocyclic and heterocyclic rings. This thesis comprises three chapters of results and discussion with the Diels-Alder reaction as a theme. Chapter 2 details an investigation of endo:exo selectivity in the Diels-Alder reactions of 1,3-butadiene. Chapter 3 explores aspects of the intramolecular Diels-Alder reactions of some substituted 1,3,8-nonatrienes, and Chapter 4 describes the domino Diels-Alder reactions of 1,4-diiodo-1,3-butadiene. The Diels-Alder reaction is powerful, general, and widely used in chemical synthesis, and it is well known that many Diels-Alder reactions exhibit endo selectivity, in accord with Alder's empirical rule. The origins of endo:exo selectivity in the Diels-Alder reaction, however, are not completely understood and there is a dearth of experimental evidence concerning the Diels-Alder reactions of the archetypal 1,3-diene, 1,3-butadiene. Chapter 2 describes a study of the Diels-Alder reactions of an isotopically labelled 1,3-butadiene with a range of simple dienophiles, allowing the endo:exo selectivities of these important reactions to be determined for the first time. The experimental data shed light on the origins of endo:exo selectivity in the Diels-Alder reaction and will serve as an important reference for future computational investigations in this area. The intramolecular Diels-Alder reaction shares many of the virtues of its intermolecular counterpart, however its use in chemical synthesis is limited because intramolecular Diels-Alder reactivity and stereoselectivity are often governed by subtle factors, and can be very difficult to predict. As part of a comprehensive experimental and computational collaboration, Chapter 3 describes an investigation of the heat and Lewis acid promoted intramolecular Diels-Alder reactions of some ether tethered 1,3,8-nonatrienes. Also presented are the results of a rate study and a kinetic isotope effect study involving the intramolecular Diels-Alder reactions of some 1,3,8-nonatrienes. The experimental data are analysed and compared with predicted stereoselectivities, activation barriers and kinetic isotope effects obtained from computational modelling. Increased efficiency in chemical synthesis conserves resources, reduces waste, and saves time and money. Domino reactions are particularly efficient processes, which can generate complex products from simple reactants. Chapter 4 describes an investigation of the domino Diels-Alder reactions of (1E,3E)-1,4-diiodo-1,3-butadiene with maleimide dienophiles, through which a family of bicyclo[2.2.2]oct-2-ene derivatives are produced in one high yielding and stereoselective synthetic step.
Download or read book The Preparation of 1 sulfur Substituted 1 3 dienes and Their Utilization in 4 2 Cycloaddition Reactions written by Zenyk Bohdan Kosarych and published by . This book was released on 1981 with total page 324 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Part I Preparation and Regioselectivity of Simple Sulfur and Selenium Substituted Dienes in the Diels Alder Reaction Part II Synthesis of Macrocyclic Polydentrate Ligands by Successive Michael Additions to Activated Acetylenes written by John Walter Verbicky and published by . This book was released on 1979 with total page 156 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Preparation and Regioselectivity of Simple Sulfur and Selenium Substituted Dienes in the Diels Alder Reaction Part I written by John Walter Verbicky and published by . This book was released on 1979 with total page 156 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Boronic Acids written by Dennis G. Hall and published by John Wiley & Sons. This book was released on 2006-05-12 with total page 571 pages. Available in PDF, EPUB and Kindle. Book excerpt: For the first time, the whole field of organoboronic acids is presented in one comprehensive handbook. Professor Dennis Hall, a rising star within the community, covers all aspects of this important substance class, including applications in chemistry, biology and medicine. Starting with an introduction to the structure, properties, and preparation of boronic acid derivatives, together with an overview of their reactions and applications, the book goes on to look at metal-catalyzed borylation of alkanes and arenas, coupling reactions and rhodium-catalyzed additions of boronic acids to alkenes and carbonyl compounds. There follows chapters on copper-promoted C-O and C-N cross-coupling of boronic acids, recent applications in organic synthesis, as well as alpha-haloalkylboronic esters in asymmetric synthesis. Later sections deal with cycloadditions, organoboronic acids, oxazaborolidines as asymmetric inducers, and boronic acid based receptors and sensors. The whole is rounded off with experimental procedures, making this invaluable reading for organic, catalytic and medicinal chemists, as well as those working in organometallics.
Download or read book Preparation and Tandem Reactions of 2 trifluoroborate Substituted Dienes written by Subhasis De and published by . This book was released on 2007 with total page 193 pages. Available in PDF, EPUB and Kindle. Book excerpt: In recent years organotrifluoroborate salts have emerged as a new class of boron derivatives, and are being widely used in different synthetic processes (e.g., Suzuki reactions, rhodium-catalyzed 1,4 additions and allylation of aldehydes). The beauty of this class of compounds lies in their monomeric nature, high stability towards air and moisture, easy preparation in high yields and they can be stored for long periods of time. To date only a few reports are available on 2-boron substituted 1,3-dienyl derivatives and corresponding DA cycloaddition chemistry presumably due to their high propensity towards dimerization. We for the first time have prepared 1,3-dienyl-2-trifluoroborates as a stable, monomeric salts and demonstrated their ability to participate in tandem Diels-Alder/cross-coupling reactions under mild conditions.
Download or read book Preparation and Diels Alder Reactivity of Novel Homochiral 1 3 butadienes written by Jessica Elizabeth Reed and published by . This book was released on 1995 with total page 318 pages. Available in PDF, EPUB and Kindle. Book excerpt:
