Download or read book I Chemoselective Catalytic Hydrogenation of alpha beta unsaturated Aldehydes and Ketones Using Soluble Copper I Hydrides written by Jianxian Chen and published by . This book was released on 1999 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book I Chemoselective Catalytic Hydrogenation of unsaturated Aldehydes and Ketones Using Soluble Copper I Hydrides II Free Radical Alkylation of Titanium III Allyl and Propargyl Complexes written by and published by . This book was released on 1999 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Free Radical Alkylation of Titanium III Allyl and Propargyl Complexes written by Jianxin Chen and published by . This book was released on 1999 with total page 508 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Hydride Mediated Homogeneous Catalysis written by Wayne S. Mahoney and published by . This book was released on 1989 with total page 344 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Catalytic Hydrogenation of Alpha Beta unsaturated Ketones in Acidic and Neutral Media written by Dominic C. Migliorini and published by . This book was released on 1966 with total page 98 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Development and Applications of Copper I Hydride Catalysis in Asymmetric Reactions and Heterocycle Synthesis written by Yujing Zhou (Ph. D.) and published by . This book was released on 2021 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Chapter 2. Enantioselective CuH-Catalyzed Hydroacylation Employing Unsaturated Carboxylic Acids as Aldehyde Surrogates The direct asymmetric copper hydride (CuH)-catalyzed coupling of [alpha],[beta]-unsaturated carboxylic acids to aryl alkenes is developed to access chiral [alpha]-aryl dialkyl ketones. A variety of substrate substitution patterns, sensitive functional groups and heterocycles are tolerated in this reaction, which significantly expands the range of accessible products compared to existing hydroacylation methodology. Although mechanistic studies are ongoing, we propose that CuH-catalyzed silylation of unsaturated acids occurs to access a uniquely effective acyl electrophilic coupling partner. Chapter 3. CuH-Catalyzed Asymmetric Reduction of [alpha],[beta]-Unsaturated Carboxylic Acids to [beta]-Chiral Aldehydes The copper hydride (CuH)-catalyzed enantioselective reduction of [alpha],[beta]-unsaturated carboxylic acids to saturated aldehydes is reported. This protocol provides a new method to access a variety of [beta]-chiral aldehydes in good yields, with high levels of enantioselectivity and broad functional group tolerance. A reaction pathway involving a ketene intermediate is proposed based on preliminary mechanistic studies and density functional theory calculations. Chapter 4. CuH-Catalyzed Asymmetric Reductive Amidation of [alpha],[beta]-Unsaturated Carboxylic Acids The direct enantioselective copper hydride (CuH)-catalyzed synthesis of [beta]-chiral amides from [alpha],[beta]-unsaturated carboxylic acids and secondary amines under mild reaction conditions is reported. The method utilizes readily accessible carboxylic acids, and tolerates a variety of functional groups at [beta]-position including several heteroarenes. A subsequent iridium-catalyzed reduction to [gamma]-chiral amines can be performed in the same flask without purification of the intermediate amides. Chapter 5. CuH-Catalyzed Asymmetric Hydroamidation of Vinylarenes A CuH-catalyzed enantioselective hydroamidation reaction of vinylarenes has been developed using readily accessible 1,4,2-dioxazol-5-ones as electrophilic amidating reagents. This method provides a straightforward and efficient approach to synthesize chiral amides in good yields with high levels of enantiopurity under mild conditions. Moreover, this transformation tolerates substrates bearing a broad range of functional groups. Chapter 6. Enantioselective Allylation Using Allene, a Petroleum Cracking Byproduct Allene (C3H4) gas is produced and separated on million-metric-ton scale per year during petroleum refining but is rarely employed in organic synthesis. Meanwhile, the addition of an allyl group (C3H5) to ketones is among the most common and prototypical reactions in synthetic chemistry. Herein, we report that the combination of allene gas with inexpensive and environmentally benign hydrosilanes, such as PMHS, can serve as a replacement for stoichiometric quantities of allylmetal reagents, which are required in most enantioselective ketone allylation reactions. This process is catalyzed by copper catalyst and commercially available ligands, operates without specialized equipment or pressurization, and tolerates a broad range of functional groups. Furthermore, the exceptional chemoselectivity of this catalyst system enables industrially relevant C3 hydrocarbon mixtures of allene with methylacetylene and propylene to be applied directly. Based on our strategy, we anticipate the rapid development of methods that leverage this unexploited feedstock as an allyl anion surrogate. Chapter 7. Synthesis of Pyrroles through the CuH-Catalyzed Coupling of Enynes and Nitriles Herein, we describe an efficient method to prepare polysubstituted pyrroles via a copper-hydride (CuH)- catalyzed enyne-nitrile coupling reaction. This protocol accommodates both aromatic and aliphatic substituents and a broad range of functional groups, providing a variety of N-H pyrroles in good yields and with high regioselectivity. We propose that the Cu-based catalyst promotes both the initial reductive coupling and subsequent cyclization steps. Density functional theory (DFT) calculations were performed to help elucidate the reaction mechanism.
Download or read book Catalytic Hydrogenation written by Christopher Michael Belisle and published by . This book was released on 1995 with total page 280 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Epoxidations and Hydroperoxidations of Unsaturated Ketones written by Corinna Reisinger and published by Springer Science & Business Media. This book was released on 2012-06-01 with total page 266 pages. Available in PDF, EPUB and Kindle. Book excerpt: Corinna Reisinger has developed a new organocatalytic asymmetric epoxidation of cyclic and acyclic α,β-unsaturated ketones. In this thesis, Corinna documents her methodology, using primary amine salts as catalysts, and hydrogen peroxide as an inexpensive and environmentally benign oxidant. She describes the unprecedented and powerful catalytic asymmetric hydroperoxidation of α,β-enones, a process which produces optically active five-membered cyclic peroxyhemiketals in a single operation. She also proves the versatility and synthetic value of the cyclic peroxyhemiketals by converting them into highly enantioenriched acyclic and cyclic aldol products. Currently, these cyclic aldol products are inaccessible by any other synthetic means. Furthermore, cyclic peroxyhemiketals are precursors to optically active 1,2-dioxolanes which are of biological relevance. This work is a breakthrough in the field of asymmetric epoxidation chemistry and outlines the most efficient method in the literature for generating highly enantioselective cyclic epoxyketones known to date.
Download or read book Selective Hydrogenation of alpha beta alpha Beta unsaturated Aldehydes Towards Clean Synthesis Over Noble Metal Catalysts in Mass Transfer Efficient Three Phase Reactors written by Laiqi Zhang and published by . This book was released on 1998 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The hydrodynamics and mass transfer characteristics of a concurrent downflow contactor (CDC) are studied in this work in order to investigate the viability of this bubble column as a catalytic reactor for the hydrogenation of?,?-unsaturated aldehydes. Oxygen/water was used as the system throughout. In order to obtain reproducible results, a very effective gas-liquid separation method was conceived and developed after much trial and error work. Shutdown and deadleg gas holdup measuring methods were compared and it was found that the shutdown method is more reliable than the deadleg method. The hydrogenation of cinnamaldehyde using both in-house-prepared and commercial palladium, platinum and ruthenium catalysts was carried out in stirred tank reactors and cocurrent downflow reactors in order to study the kinetics and mass transfer characteristics and the selectivity towards the corresponding desired product, hydrocinnamaldehyde or cinnamyl alcohol. When palladium catalysts were used the desired product was hydrocinnamaldehyde. The effects of homogenous reactions, type of solvent, catalyst loading, temperature, pressure, reactant concentration and the effects of promoter or poison on the selectivity towards hydrocinnamaldehyde were investigated systematically. Aldehyde acetals were produced in polar solvents, but not in non-polar solvents. Two methods can be used to obtain hydrocinnamaldehyde selectivity without reduction of the carbonyl double bond: (1) by using non-polar solvents such as toluene; (2) by incorporating poisons or promoters into the reactant solution or onto the surface of the catalysts. 97% selectivity to hydrocinnamaldehyde was achieved. The effects of the solvent, temperature, pressure, catalyst loading, promoters, and reactants concentration on the kinetics were studied and the following reaction kinetics are proposed for the hydrogenation of cinnamaldehyde over non-modified palladium/charcoal catalysts in propan-2-ol and in toluene: Ra = kC\(_{Cat}\)C\(_{H2}\)C\(0_{CAL}\) The apparent activation energy varies with themperature range in propan-2-ol and is 65\(\pm\)5 kJ.mol\({-1}\) in toluene.
Download or read book Handbook of Heterogeneous Catalytic Hydrogenation for Organic Synthesis written by Shigeo Nishimura and published by Wiley-Interscience. This book was released on 2001-04-17 with total page 728 pages. Available in PDF, EPUB and Kindle. Book excerpt: A complete guide to the most important reduction method in organic synthesis The most comprehensive reference in the field, Handbook of Heterogeneous Catalytic Hydrogenation for Organic Synthesis provides synthetic chemists and chemical engineers in fine chemicals and pharmaceuticals with detailed experimental guidelines for heterogeneous catalytic hydrogenation. Organized by functional groups for ready reference and featuring detailed examples of hundreds of reactions, this handbook covers hydrogenations of alkenes, alkynes, aldehydes and ketones, nitriles, imines, nitro and nitroso compounds, carboxylic acids and esters, and aromatic and heterocyclic compounds. In addition, coverage includes the preparation of amines by reductive alkylation and the hydrogenolysis of a variety of compounds. Examples of hydrogenation of functional groups and reaction pathways are illustrated with numerous equations and schemes. Practitioners will appreciate the plenitude of experimental details given for most of the reactions selected, including amounts of reagents and catalysts, reaction temperatures, hydrogen pressures, and reaction times. They will also find helpful the more than one hundred tables included throughout the book detailing the effects of key factors governing rate and selectivity, such as compound structure, the nature of catalysts and supports, and the nature of solvents. Researchers will benefit from the introductory chapters covering an array of hydrogenation catalysts, including nickel, cobalt, copper, iron, platinum group metals, rhenium, and other oxide and sulfide catalysts, as well as reactors and reaction conditions.
Download or read book Selective Hydrogenation of alpha beta unsaturated Aldehydes Over Metal Catalysts written by Thomas Balder Ludwig Wolfgang Marinelli and published by . This book was released on 1993 with total page 129 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Catalytic Hydrogenation in Organic Synthesis written by Morris Freifelder and published by John Wiley & Sons. This book was released on 1978-11 with total page 218 pages. Available in PDF, EPUB and Kindle. Book excerpt: Based on over 22 years of experience, this book presents a substantial accumulation of knowledge. Clearly and understandably written, it gives detailed descriptions of many experiments, providing step-by-step procedures along with personal notes and observations, directions, suggestions, and safety precautions. The yields obtained in these experiments are good to excellent, and most of the hydrogenations discussed are carried out under very mild conditions.
Download or read book Selective Hydrogenation of alpha beta unsaturated Aldehydes Towards Clean Synthesis Over Noble Metal Catalysts in Mass Transfer Efficient Three Phase Reactors written by Laiqi Zhang and published by . This book was released on 1998 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The hydrodynamics and mass transfer characteristics of a concurrent downflow contactor (CDC) are studied in this work in order to investigate the viability of this bubble column as a catalytic reactor for the hydrogenation of ?,?-unsaturated aldehydes. Oxygen/water was used as the system throughout. In order to obtain reproducible results, a very effective gas-liquid separation method was conceived and developed after much trial and error work. Shutdown and deadleg gas holdup measuring methods were compared and it was found that the shutdown method is more reliable than the deadleg method. The hydrogenation of cinnamaldehyde using both in-house-prepared and commercial palladium, platinum and ruthenium catalysts was carried out in stirred tank reactors and cocurrent downflow reactors in order to study the kinetics and mass transfer characteristics and the selectivity towards the corresponding desired product, hydrocinnamaldehyde or cinnamyl alcohol. When palladium catalysts were used the desired product was hydrocinnamaldehyde. The effects of homogenous reactions, type of solvent, catalyst loading, temperature, pressure, reactant concentration and the effects of promoter or poison on the selectivity towards hydrocinnamaldehyde were investigated systematically. Aldehyde acetals were produced in polar solvents, but not in non-polar solvents. Two methods can be used to obtain hydrocinnamaldehyde selectivity without reduction of the carbonyl double bond: (1) by using non-polar solvents such as toluene; (2) by incorporating poisons or promoters into the reactant solution or onto the surface of the catalysts. 97% selectivity to hydrocinnamaldehyde was achieved. The effects of the solvent, temperature, pressure, catalyst loading, promoters, and reactants concentration on the kinetics were studied and the following reaction kinetics are proposed for the hydrogenation of cinnamaldehyde over non-modified palladium/charcoal catalysts in propan-2-ol and in toluene: Ra = kC\(-{Cat}\)C\(-{H2}\)C\( 0-{CAL}\) The apparent activation energy varies with themperature range in propan-2-ol and is 65\(\pm\)5 kJ.mol\( {-1}\) in toluene.
Download or read book Promotion Effects in Catalytic Hydrogenation of Aldehydes and Ketones written by Gerry Martina Regina Druten and published by . This book was released on 1999 with total page 122 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Promotion Effects in Catalytic Hydrogenation of Aldehydes and Ketones written by Gerry van Druten and published by . This book was released on 1999 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Selective Hydrogenation of alpha beta Unsaturated Aldehydes Over Ir Catalysts written by J. Gomez-Lopez and published by . This book was released on 2004 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Selective Hydrogenation of Alpha Beta unsaturated Aldehydes Towards Clean Synthesis Over Noble Metal Catalysts in Mass Transfer Efficient Three Phase Reactors written by Lai Qi Zhang and published by . This book was released on 1997 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
