Pd- and Ni-based Catalysts for Mild C-S Bond Activation and Formation PDF Download

Author: Paul Gehrtz
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Author: Nootaree Niljianskul
Publisher:
ISBN:
Category :
Languages : en
Pages : 635

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The research presented in this dissertation is aimed at the development of novel methodologies for carbon-heteroatom cross-coupling reactions catalyzed by late-transition metals. Both palladium and copper are central to the field of transition metal-catalysis and are integral to the catalyst systems developed as part of our continual advancement in cross-coupling reactions. The first part of this thesis focuses on the use of palladium catalysts to form carbon-sulfur bonds directed towards aryl sulfonamide synthesis. The second part of the thesis describes the recent development in the copper(!) hydride mediated formation of carbon-nitrogen bonds via hydroamination of olefins. Part I. Chapter 1. Palladium-Catalyzed Chlorosulfonylation of Arylboronic Acids Using a biaryl phosphine ligand platform, the first palladium-catalyzed cross-coupling reaction of phenyl chlorosulfate with arylboronic acids was achieved. In this context, the arylsulfonyl chloride products serve as useful precursors to a variety of sulfonyl functional groups, such as aryl sulfonamides, aryl sulfones, and arenesulfonate esters. In particular, this method allows for the preparation of a number of arylsulfonyl chlorides that are not accessible via electrophilic aromatic substitution pathways and under mild reaction conditions. Additionally, this methodology points to an unprecedented selectivity for the phenylchlorosulfate electrophiles used in the cross-coupling reactions. Part II. Chapter 2. Enantio- and Regioselective Copper-Catalyzed Hydroamination of Styrenes and the Extension of the Methodology towards Anti-Markovnikov Hydroamination of Terminal Aliphatic Alkenes The development of a copper-mediated strategy towards the hydroamination of styrene derivatives is reported. In this system, the reaction proceeds regioselectively and enantioselectively to generate [alpha]-branched amines. The system can transform a wide variety of substituted styrenes, including trans-, cis-, and [beta]-disubstituted styrenes. In addition, our extension to copper-catalyzed hydroamination reactions of unactivated aliphatic olefins is reported. Using terminal aliphatic alkenes, the copper-catalyzed hydroamination reactions proceed with anti-Markovnikov regioselectivity. Preliminary results point to the application of this methodology towards [beta]-chiral amine synthesis via the hydroamination of I, 1-disubstituted alkenes. Chapter 3. [alpha]-Aminosilane Synthesis via Copper-Catalyzed Hydroamination of Vinylsilanes The copper-catalyzed hydroamination of vinylsilanes is described. This regioselective reaction generates a-chiral aminosilanes in high yields and enantioselectivities. The method is compatible with differentially substituted vinylsilanes and allows access to many valuable chiral organosilicon compounds. Chapter 4. Synthesis of [gamma]-Chiral Amines via Copper-Catalyzed Hydroamination of 3,3- Disubstituted Allylic Alcohols and 3,3-Disubstituted Allylic Benzoates An investigation into the copper-catalyzed hydroamination of allylic alcohols and allylic benzoates is reported. The reaction proceeds via a [beta]-alkoxy elimination, setting a stereogenic center at the 3-postion to generate [gamma]-chiral amine products. The reaction is more efficient using allylic benzoates. This method is completely regioselective and is applicable to aliphatic allylic benzoates as well as aromatic allylic benzoates. Additionally, we demonstrated that this strategy is applicable towards an allylic epoxide substrate to generate [delta]-chiral amine.

Author: Joseph P. Tassone
Publisher:
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Category :
Languages : en
Pages :

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In this investigation, the catalytic utility of anionic, phosphinobenzimidzoles [Li(THF)2][1a] and [Li(THF)4][1b] in effecting the Buchwald-Hartwig amination reaction was examined. Specifically, the coordination chemistry of ligands [Li(THF)2][1a] and [Li(THF)4][1b] with palladium was studied in an attempt to synthesize a distinct precatalyst containing either 1a or 1b that could be screened for catalytic activity in the reaction of interest. Additionally, the screening of a Pd/[Li(THF)4][1b] catalyst system for activity in the Buchwald-Hartwig amination reaction was conducted concurrently. Complex 6, containing 1a, and complexes 7-12, containing 1b, were successfully synthesized, and characterized using multi-nuclear NMR spectroscopy. An optimized [Pd(cinnamyl)Cl]2/[Li(THF)4][1b] catalyst system was also developed, and performed the coupling of activated and deactivated aryl bromides with a selection of amines in moderate to excellent yields (36-97%). A preference for primary vs. secondary amine coupling partners, as well as a high selectivity for the monoarylated product, was observed during the course of these studies. To highlight the remarkable potential of anionic ligands in catalysis, the catalytic efficiency of the [Pd(cinnamyl)Cl]2/[Li(THF)4][1b] catalyst system was compared with a corresponding system utilizing the related, neutral phosphinobenzimidazole 2, with the anionic system displaying superior catalytic activity in the Buchwald-Hartwig amination reaction in almost all cases. This phenomenon was attributed to the more electron-rich catalytic intermediates present in the anionic system, enabling more rapid oxidative addition, and thus more efficient catalysis. Further screening of the anionic precatalyst [PPh4][PdCl2(k2-1b)] (10) and neutral precatalyst [PdCl2(k2-2)] (13) corroborated these results. Finally, preliminary studies examining the potential of 1b as an ancillary ligand in Ni-catalyzed C-N bond formation was undertaken. The coordination chemistry of 1b with nickel was explored, resulting in the formation of complex 14, whose tentative structure was assigned on the basis of NMR spectroscopic evidence. Furthermore, initial screening of a NiCl2(DME)/[Li(THF)4][1b] catalyst system in the cross-coupling of chlorobenzene and aniline did not result in observable product formation under various reaction conditions.

Author: R. T. K. Baker
Publisher:
ISBN:
Category : Science
Languages : en
Pages : 258

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Author: Pietro Tundo
Publisher: Springer
ISBN: 3319300733
Category : Science
Languages : en
Pages : 614

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Since the industrial revolution, chlorine remains an iconic molecule even though its production by the electrolysis of sodium chloride is extremely energy intensive. The rationale behind this book is to present useful and industrially relevant examples for alternatives to chlorine in synthesis. This multi-authored volume presents numerous contributions from an international spectrum of authors that demonstrate how to facilitate the development of industrially relevant and implementable breakthrough technologies. This volume will interest individuals working in organic synthesis in industry and academia who are working in Green Chemistry and Sustainable Technologies.

Author: Walter Kaminsky
Publisher: Wiley-VCH
ISBN: 9783527317424
Category : Technology & Engineering
Languages : en
Pages : 0

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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.

Author: Arkadi Vigalok
Publisher: Springer
ISBN: 3642120733
Category : Science
Languages : en
Pages : 198

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Contents: Kilian Muñiz: Transition Metal Catalyzed Electrophilic Halogenation of C-H bonds in alpha-Position to Carbonyl Groups; Arkadi Vigalok * and Ariela W Kaspi: Late Transition Metal-Mediated Formation of Carbon-Halogen Bonds; Paul Bichler and Jennifer A. Love*: Organometallic Approaches to Carbon-Sulfur Bond Formation; David S. Glueck: Recent Advances in Metal-Catalyzed C-P Bond Formation; Andrei N. Vedernikov: C-O Reductive Elimination from High Valent Pt and Pd Centers; Lukas Hintermann: Recent Developments in Metal-Catalyzed Additions of Oxygen Nucleophiles to Alkenes and Alkynes; Moris S. Eisen: Catalytic C-N, C-O and C-S bond formation promoted by organoactinide complexes.

Author: Xiaohua Huang
Publisher:
ISBN:
Category :
Languages : en
Pages : 432

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New methods for Pd-catalyzed cross-coupling reactions of aryl halides or arenesulfonates are described. Key to the success of these transformations is the proper choice of ligand and reaction conditions. Palladium catalysts supported by bulky, monodentate phosphine ligands with a biaryl backbone or the bidentate ligand, Xantphos, effectively promote the formation of ca-aryl carbonyl compounds. Base-sensitive functional groups are better tolerated when a weak base, such as K3PO4, is used. One of the most difficult transformations in Pd catalysis, the intermolecular C-O bond formation between primary alcohols and electron-neutral or even electron-rich aryl halides, was effectively promoted by the use of a new generation of ligands, 3-methyl-2-di-t-butylphosphinobiaryl. The one-step synthesis of ligands from cheap starting materials, as well as the mild reaction conditions employed for the coupling reactions, enables the practical use of Pd catalysis to access aryl alkyl ethers for the first time. Continuing study of Pd-catalyzed C-N bond-forming processes using biaryl monophosphine ligands led to the discovery of a structural derivative of these ligands, 2-dicyclohexylphosphino-2',4',6'-triisopropylbiphenyl. This ligand, in combination with a Pd source, produces a catalyst system with both a greater degree of activity and of stability than those that use our previous ligands. Substrates that were not amenable to Pd catalysis previously are reexamined using this new catalyst system, and excellent results are obtained.

Author: Dionysios D Dionysiou
Publisher: Royal Society of Chemistry
ISBN: 1782627103
Category : Science
Languages : en
Pages : 395

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From environmental remediation to alternative fuels, this book explores the numerous important applications of photocatalysis. The book covers topics such as the photocatalytic processes in the treatment of water and air; the fundamentals of solar photocatalysis; the challenges involved in developing self-cleaning photocatalytic materials; photocatalytic hydrogen generation; photocatalysts in the synthesis of chemicals; and photocatalysis in food packaging and biomedical and medical applications. The book also critically discusses concepts for the future of photocatalysis, providing a fascinating insight for researchers. Together with Photocatalysis: Fundamentals and Perspectives, these volumes provide a complete overview to photocatalysis.

Author: Sensuke Ogoshi
Publisher: John Wiley & Sons
ISBN: 3527344071
Category : Science
Languages : en
Pages : 348

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A comprehensive reference to nickel chemistry for every scientist working with organometallic catalysts Written by one of the world?s leading reseachers in the field, Nickel Catalysis in Organic Synthesis presents a comprehensive review of the high potential of modern nickel catalysis and its application in synthesis. Structured in a clear and assessible manner, the book offers a collection of various reaction types, such as cross-coupling reactions, reactions for the activation of unreactive bonds, carbon dioxide fixation, and many more. Nickel has been recognized as one of the most interesting transition metals for homogeneous catalysis. This book offers an overview to the recently developed new ligands, new reaction conditions, and new apparatus to control the reactivity of nickel catalysts, allowing scientists to apply nickel catalysts to a variety of bond-forming reactions. A must-read for anyone working with organometallic compounds and their application in organic synthesis, this important guide: -Reviews the numerous applications of nickel catalysis in synthesis -Explores the use of nickel as a relatively cheap and earth-abundant metal -Examines the versatility of nickel catalysis in reactions like cross-coupling reactions and CH activations -Offers a resource for academics and industry professionals Written for catalytic chemists, organic chemists, inorganic chemists, structural chemists, and chemists in industry, Nickel Catalysis in Organic Synthesis provides a much-needed overview of the most recent developments in modern nickel catalysis and its application in synthesis.