Controlling Selectivity in Novel Transition Metal Catalyzed Carbon-carbon Bond Forming Hydrogenations PDF Download
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Author: Jason Robert Zbieg
Publisher:
ISBN:
Category :
Languages : en
Pages : 934
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Book Description
The focus of my graduate research in the Krische group has been the development of catalytic carbon-carbon bond forming reactions with an emphasis on controlling diastereo- and enatio-selectivity in transfer hydrogenative couplings. The broad goal of our research program has been the development and implementation of efficient green methods for carbonyl addition employing [pi]-unsaturates as surrogates to preformed organometallic reagents, thus enabling byproduct free variants of traditional carbanion chemistry. This dissertation shows the new reactions that I have developed toward this goal. These reactions includes new metal catalyzed approaches for carbonyl crotylation, aminoallylation, and vinylogous reformatsky aldol reactions.
Author: Jason Robert Zbieg
Publisher:
ISBN:
Category :
Languages : en
Pages : 934
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Book Description
The focus of my graduate research in the Krische group has been the development of catalytic carbon-carbon bond forming reactions with an emphasis on controlling diastereo- and enatio-selectivity in transfer hydrogenative couplings. The broad goal of our research program has been the development and implementation of efficient green methods for carbonyl addition employing [pi]-unsaturates as surrogates to preformed organometallic reagents, thus enabling byproduct free variants of traditional carbanion chemistry. This dissertation shows the new reactions that I have developed toward this goal. These reactions includes new metal catalyzed approaches for carbonyl crotylation, aminoallylation, and vinylogous reformatsky aldol reactions.
Author: Timothy Patrick Montgomery
Publisher:
ISBN:
Category :
Languages : en
Pages : 1092
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Book Description
A central tenant of organic synthesis is the construction of carbon-carbon bonds. One of the traditional methods for carrying out such transformations is that of carbonyl addition. Unfortunately, traditional carbonyl addition chemistry suffers various drawbacks: preactivation, moisture sensitivity, and the generation of stoichiometric organometallic waste. The research presented in this dissertation focuses on the development of methods that make use of nucleophile-electrophile pairs generated in situ via transfer hydrogenation, which allow the formation of carbonyl or imine addition products from the alcohol or amine oxidation level; streamlining the construction of complex molecules from simple, readily available starting materials. Additionally, studies toward the total synthesis of the fibrinogen receptor inhibitor tetrafibricin, utilizing the methods developed in catalytic carbon-carbon bond formation through the addition, transfer or removal of hydrogen, are presented.
Author: Jianbo Wang
Publisher: John Wiley & Sons
ISBN: 3527347992
Category : Science
Languages : en
Pages : 450
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Book Description
Presents an up-to-date overview of the rapidly growing field of carbene transformations Carbene transformations have had an enormous impact on catalysis and organometallic chemistry. With the growth of transition metal-catalyzed carbene transformations in recent decades, carbene transformations are today an important compound class in organic synthesis as well as in the pharmaceutical and agrochemical industries. Edited by leading experts in the field, Transition Metal-Catalyzed Carbene Transformations is a thorough summary of the most recent advances in the rapidly expanding research area. This authoritative volume covers different reaction types such as ring forming reactions and rearrangement reactions, details their conditions and properties, and provides readers with accurate information on a wide range of carbene reactions. Twelve in-depth chapters address topics including carbene C-H bond insertion in alkane functionalization, the application of engineered enzymes in asymmetric carbene transfer, progress in transition-metal-catalyzed cross-coupling using carbene precursors, and more. Throughout the text, the authors highlight novel catalytic systems, transformations, and applications of transition-metal-catalyzed carbene transfer. Highlights the dynamic nature of the field of transition-metal-catalyzed carbene transformations Summarizes the catalytic radical approach for selective carbene cyclopropanation, high enantioselectivity in X-H insertions, and bio-inspired carbene transformations Introduces chiral N,N'-dioxide and chiral guanidine-based catalysts and different transformations with gold catalysis Discusses approaches in cycloaddition reactions with metal carbenes and polymerization with carbene transformations Outlines multicomponent reactions through gem-difunctionalization and transition-metal-catalyzed cross-coupling using carbene precursors Transition Metal-Catalyzed Carbene Transformations is essential reading for all chemists involved in organometallics, including organic and inorganic chemists, catalytic chemists, and chemists working in industry.
Author: Brannon Sam
Publisher:
ISBN:
Category :
Languages : en
Pages : 1026
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Book Description
Author: Ming-yu Ngai
Publisher:
ISBN:
Category : Chemical bonds
Languages : en
Pages : 652
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Book Description
Carbon-carbon bond forming reactions are vital to the synthesis of natural products and pharmaceuticals. In 2003, the 200 best selling prescription drugs reported in Med Ad News are all organic compounds. Synthesizing these compounds involves many carbon-carbon bond forming processes, which are not trivial and typically generate large amounts of waste byproducts. Thus, development of an atom economical and environmentally benign carbon-carbon bond forming methodology is highly desirable. Hydrogenation is one of the most powerful catalytic reactions and has been utilized extensively in industry. Although carbon-carbon bond forming reactions under hydrogenation conditions, such as, alkene hydroformylation and the Fischer-Tropsch reaction are known, they are limited to the coupling of unsaturated hydrocarbons to carbon monoxide. Recently, a breakthrough was made by the Krische group, who demonstrated that catalytic hydrogenative C-C bond forming reactions can be extended to the coupling partners other than carbon monoxide. This discovery has led to the development of a new class of carbon-carbon bond forming reactions. Herein, an overview of transition metal-catalyzed reductive couplings of [pi]-unsaturated systems employing various external reductants is summarized in Chapter 1. Chapters 2-4 describe a series of rhodium- and iridium-catalyzed asymmetric hydrogenative couplings of various alkynes to a wide range of imines and carbonyl compounds. These byproduct-free transformations provide a variety of optically enriched allylic amines and allylic alcohols, which are found in numerous natural products, and are used as versatile precursors for the synthesis of many biologically active compounds. Transfer hydrogenation represents another important class of reactions in organic chemistry. This process employs hydrogen sources other than gaseous dihydrogen, such as isopropanol. The Krische group succeeded in developing a new family of transfer hydrogenative carbon-carbon bond formation reactions. Chapter 5 presents two novel ruthenium- and iridium-catalyzed transfer hydrogenative carbonyl allylation reactions. The catalytic system employing iridium complexes enables highly enantioselective carbonyl allylation from both the alcohol and aldehyde oxidation level. These systems define a departure from the use of preformed organometallic reagents in carbonyl additions that transcends the boundaries of oxidation level.
Author: Christopher Masters
Publisher: Springer Science & Business Media
ISBN: 9400958803
Category : Science
Languages : en
Pages : 284
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Book Description
Soluble catalysts are used extensively in many branches of chemistry and are indeed a vital constituent of many natural processes. They find wide application throughout the chemical industry where they assist in the production of several million tonnes of chemicals each year. Since homogeneous systems, especially those incorporating transition metals, often function effectively under milder conditions than their heterogeneous counterparts, they are becoming increasingly important at a time when the chemical industry in particular, and society in general, is seeking ways of conserving energy and of making the best possible use of available resources. My principal objective in- writing this book is to engender sufficient enthusiasm for, and knowledge of, the subject in the reader that he or she will be encouraged to begin, or continue, to make their own contribution to advancing our knowledge of homogeneous catalysis. After attempting to acquaint the reader with some of the ground rules I have tried to describe the present scope, and the future potential, of this fascinating field of chemistry by drawing both on academic and on industrial data sources. This approach stems from a personal conviction that future progress could be considerably hastened by a more meaningful dialogue between chemists working both in industrial and in academic research institutions. Wherever possible, examples of the commercial application of homogeneous catalyst systems have been included and no attempt has been made in any way to disguise the many unresolved questions and exciting challenges which still pervade this rapidly developing area.
Author: András Kotschy
Publisher: Springer Science & Business Media
ISBN: 9781402036248
Category : Science
Languages : en
Pages : 224
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Book Description
"Heterocycles from Transition Metal Catalysis: Formation and Functionalization" provides a concise summary of the prominent role of late transition metal (palladium, nickel, copper) catalysed processes in the synthesis and functionalization of heterocyclic systems. It gives an introduction to catalytic transformations, an overview of the most important reaction types, and presents synthetically useful catalytic processes classified by the target system and the type of transformation. The book provides a representative selection of transition metal catalysed reactions transformations that are relevant in heterocyclic chemistry. In this way, the authors present a useful resource for members of the academic community looking for a textbook as well as industrial chemists in search of a reference book. This book will be an invaluable resource for synthetic chemists, medicinal chemists, and those more generally interested in applied catalysis.
Author: Abbas Hassan
Publisher:
ISBN:
Category :
Languages : en
Pages : 670
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Book Description
In Michael J. Krische research group we are developing new transition metal catalyzed Carbon-Carbon (C-C) forming reactions focusing on atom economy and byproduct free, environmental friendly approaches. We have developed a broad family of C-C bond forming hydrogenations with relative and absolute stereocontrol which provide an alternative to stoichiometric organometallic reagents in certain carbonyl and imine additions. Inspiring from the group work my goal was to develop new reactions, extend the scope of our group chemistry and their application towards synthesis of biologically active natural products. I have been part of enantioselective Rh catalyzed Aldol reaction of vinyl ketones to different aldehydes. Also, we have found that iridium catalyzed transfer hydrogenation of allylic acetates in the presence of aldehydes or alcohols results in highly enantioselective carbonyl allylation under the conditions of transfer hydrogenative. Based on this reactivity a concise enantio- and diastereoselective synthesis of 1,3-polyols was achieved via iterative chain elongation and bidirectional iterative asymmetric allylation was performed, which enables the rapid assembly of 1,3-polyol substructures with exceptional levels of stereocontrol. The utility of this approach stems from the ability to avoid the use of chirally modified allylmetal reagents, which require multistep preparation, and the ability to perform chain elongation directly from the alcohol oxidation level. This approach was utilized for the total synthesis of (+)-Roxaticin from 1,3-propanediol in 20 longest linear steps and a total number of 29 manipulations. Further, advancements were made in iridium catalyzed C-C bond formation under transfer hydrogenation. While methallyl acetate does not serve as an efficient allyl donor, the use of more reactive leaving group in methallyl chloride compensate for the shorter lifetime of the more highly substituted olefin [pi]-complex. Based on this insight into the requirements of the catalytic process, highly enantioselective Grignard-Nozaki-Hiyama methallylation is achieved from the alcohol or aldehyde oxidation levels. Also, a catalytic method for enantioselective vinylogous Reformatsky- type aldol addition was developed in which asymmetric carbonyl addition occurs with equal facility from the alcohol or aldehyde oxidation level. Good to excellent levels of regioselectivity and uniformly high levels of enantioselectivity were observed across a range of alcohols and aldehydes.
Author: Kaixu Yuan
Publisher:
ISBN:
Category : Carbon compounds
Languages : en
Pages : 420
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Book Description
Author: Janine Cossy
Publisher: Walter de Gruyter GmbH & Co KG
ISBN: 3110383438
Category : Science
Languages : en
Pages : 416
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Book Description
In 1912, the Chemistry Nobel Prize was awarded for the discovery of the so-called Grignard reagents. Nowadays, many transition metal variants are developed to modify reactivity and selectivity of the C–C bond formation reaction. The Grignard reaction is one of the fundamental organometallic reactions, often used in alcohol syntheses. With transition metals like iron, cobalt and nickel or with noble metals like copper, silver and palladium, modern Grignard reagents can be designed in reactivity, selectivity and functional group tolerance. This book, written by international experts, presents an overview on timely Grignard chemistry involving transition metals.
