Studies in Enantioselective Transition Metal Catalysis Using Modular Phosphine-Phosphite Ligands Copper-catalyzed 1,4-Addition of Grignard Reagents to alpha,beta-Unsaturated Carbonyl Compounds

Studies in Enantioselective Transition Metal Catalysis Using Modular Phosphine-Phosphite Ligands Copper-catalyzed 1,4-Addition of Grignard Reagents to alpha,beta-Unsaturated Carbonyl Compounds
Author: Qaseem Naeemi
Publisher:
Total Pages: 151
Release: 2012
Genre:
ISBN: 9783843903172

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Chiral Phosphorous Based Ligands in Earth-Abundant Transition Metal Catalysis

Chiral Phosphorous Based Ligands in Earth-Abundant Transition Metal Catalysis
Author: Junliang Zhang
Publisher: Elsevier
Total Pages: 322
Release: 2023-05-27
Genre: Science
ISBN: 0323852262

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Chiral Phosphorous Based Ligands in Earth-Abundant Transition Metal Catalysis summarizes the most significant progress in the field of chiral phosphine ligand chemistry and a broad range of earth-abundant transition metal/chiral phosphine ligand-catalyzed enantioselective transformations. The book provides an authoritative and in-depth understanding of important topics about asymmetric catalysis based on earth-abundant transition metals/chiral phosphine ligands, making it ideal for organic chemistry researchers working in the field of asymmetric catalysis, synthetic methodologies and total synthesis.The development of new chiral phosphine ligands to achieve precise stereo control in many earth-abundant transition metal-catalyzed reactions is a very important field in organic synthesis, materials science and medicinal chemistry. The asymmetric synthesis promoted by transition metal/chiral phosphine ligands provides one of the most ideal ways to produce valuable optically active chemicals. Includes a discussion of state-of-the-art asymmetric organic reactions mediated by earth-abundant transition metals and chiral phosphine ligands Features the progress and the prospect of chiral phosphine ligands in asymmetric transition metal catalysis Covers the asymmetric reactivity modes of earth-abundant transition metals and phosphine ligands

Homogeneous Catalysis with Metal Phosphine Complexes

Homogeneous Catalysis with Metal Phosphine Complexes
Author: Louis M. Pignolet
Publisher: Springer Science & Business Media
Total Pages: 494
Release: 2013-11-21
Genre: Science
ISBN: 1461336236

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The field of transition metal catalysis has experienced incredible growth during the past decade. The reasons for this are obvious when one considers the world's energy problems and the need for new and less energy demanding syntheses of important chemicals. Heterogeneous catalysis has played a major industrial role; however, such reactions are generally not selective and are exceedingly difficult to study. Homogeneous catalysis suffers from on-site engineering difficulties; however, such reactions usually provide the desired selectivity. For example, Monsanto's synthesis of optically-active amino acids employs a chiral homogeneous rhodium diphosphine catalyst. Industrial uses of homogeneous catalyst systems are increasing. It is not by accident that many homogeneous catalysts contain tertiary phosphine ligands. These ligands possess the correct steric and electronic properties that are necessary for catalytic reactivity and selectivity. This point will be emphasized throughout the book. Thus the stage is set for a comprehensive be treatment of the many ways in which phosphine catalyst systems can designed, synthesized, and studied.

Artificial Metalloenzymes and MetalloDNAzymes in Catalysis

Artificial Metalloenzymes and MetalloDNAzymes in Catalysis
Author: Montserrat Diéguez
Publisher: John Wiley & Sons
Total Pages: 431
Release: 2018-02-21
Genre: Technology & Engineering
ISBN: 3527804072

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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.

Asymmetric Organocatalysis Combined with Metal Catalysis

Asymmetric Organocatalysis Combined with Metal Catalysis
Author: Bruce A. Arndtsen
Publisher: Springer Nature
Total Pages: 211
Release: 2020-04-24
Genre: Science
ISBN: 3030438511

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The series Topics in Current Chemistry Collections presents critical reviews from the journal Topics in Current Chemistry organized in topical volumes. The scope of coverage is all areas of chemical science including the interfaces with related disciplines such as biology, medicine and materials science. The goal of each thematic volume is to give the non-specialist reader, whether in academia or industry, a comprehensive insight into an area where new research is emerging which is of interest to a larger scientific audience.Each review within the volume critically surveys one aspect of that topic and places it within the context of the volume as a whole. The most significant developments of the last 5 to 10 years are presented using selected examples to illustrate the principles discussed. The coverage is not intended to be an exhaustive summary of the field or include large quantities of data, but should rather be conceptual, concentrating on the methodological thinking that will allow the non-specialist reader to understand the information presented. Contributions also offer an outlook on potential future developments in the field.The chapter "Enamine/Transition Metal Combined Catalysis: Catalytic Transformations Involving Organometallic Electrophilic Intermediates" is available open access under a CC BY 4.0 License via link.springer.com.

Synthesis and Application of New Chiral Ligands for Enantioselectivity Tuning in Transition Metal Catalysis

Synthesis and Application of New Chiral Ligands for Enantioselectivity Tuning in Transition Metal Catalysis
Author: Fanji Kong
Publisher:
Total Pages: 156
Release: 2017
Genre: Chirality
ISBN:

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A set of five new C3-symmetric phosphites were synthesized and tested in palladium-catalyzed asymmetric Suzuki coupling. The observed reactivity and selectivity were dependent upon several factors. One of the phosphites was able to achieve some of the highest levels of enantioselectivity in asymmetric Suzuki couplings with specific substrates. Different hypotheses have been made for understanding the ligand effects and reaction selectivities, and those hypotheses were tested via various methods including DOSY NMR experiments, X-ray crystallography, and correlation of catalyst selectivity with Tolman cone angles. Although only modest enantioselectivities were observed in most reactions, the ability to synthesis these phosphites in only three steps on gram scales and to readily tune their properties by simple modification of the binaphthyl 2́-substituents makes them promising candidates for determining structure-selectivity relationships in asymmetric transition metal catalysis, in which phosphites have been previously shown to be successful. A series of novel chiral oxazoline-based carbodicarbene ligands was targeted for synthesis. Unfortunately, the chosen synthetic route could not be completed due to unwanted reactivity of the oxazoline ring. However, a new and efficient route for Pd-catalyzed direct amination of aryl halides with oxazoline amine was developed and optimized during these studies. Chiral binaphthyl based Pd(II) ADC complexes with different substituent groups have been synthesized and tested in asymmetric Suzuki coupling reactions. Although only low enantioselectivities were observed in Suzuki coupling, this represents a new class of chiral metal-ADC catalysts that could be tested in further catalytic.

Transition Metal Catalyzed Enantioselective Allylic Substitution in Organic Synthesis

Transition Metal Catalyzed Enantioselective Allylic Substitution in Organic Synthesis
Author: Uli Kazmaier
Publisher: Springer Science & Business Media
Total Pages: 354
Release: 2011-10-29
Genre: Science
ISBN: 3642227481

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Giovanni Poli, Guillaume Prestat, Frédéric Liron, Claire Kammerer-Pentier: Selectivity in Palladium Catalyzed Allylic Substitution.- Jonatan Kleimark and Per-Ola Norrby: Computational Insights into Palladium-mediated Allylic Substitution Reactions.- Ludovic Milhau, Patrick J. Guiry: Palladium-catalyzed enantioselective allylic substitution.- Wen-Bo Liu, Ji-Bao Xia, Shu-Li You: Iridium-Catalyzed Asymmetric Allylic Substitutions.- Christina Moberg: Molybdenum- and Tungsten-Catalyzed Enantioselective Allylic Substitutions.- Jean-Baptiste Langlois, Alexandre Alexakis: Copper-catalyzed enantioselective allylic substitution.- Jeanne-Marie Begouin, Johannes E. M. N. Klein, Daniel Weickmann, B. Plietker: Allylic Substitutions Catalyzed by Miscellaneous Metals.- Barry M. Trost, Matthew L. Crawley: Enantioselective Allylic Substitutions in Natural Product Synthesis.

Developing P-Stereogenic Phosphine Ligand for Transition Metal Catalyzed Asymmetric Hydrogenation

Developing P-Stereogenic Phosphine Ligand for Transition Metal Catalyzed Asymmetric Hydrogenation
Author: Heng Wang
Publisher:
Total Pages: 0
Release: 2022
Genre:
ISBN:

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This dissertation focusses on the discussion of how empirical ligand design works on the development of chiral pincer ligands in the field of asymmetric hydrogenation. Although the design art of bisphosphine ligands was well-established, this empirical guide for pincer ligand design is still ambiguous. Developing a ligand design guide based on the nature of metals enables synthetic chemists to improve the catalytic performance without investing large numbers of time, develop highly efficient catalysts for industrial uses, or explore new areas and mechanistic insights. Learning from the history of chiral pincer ligand development, over 14 categories of pincer ligands were reported according to the coordinating atoms by the time that this dissertation was prepared. Firstly, the ligand design and relevant catalytic performance of different ligand categories were summarized and discussed in prevalent noble metal catalysis such as Ru(II), Ir(III). Based on the nature of Fe(II) with respect to noble metals, a novel PNP-type ligand HengPNP (L) was designed and successfully synthesized. Empirical design perspectives were discussed, and the ligand was characterized by NMR, HRMS. Its corresponding Fe(II) complex was studied by X-ray crystallographic technique. However, the Fe(II) carbonyl complex was thermodynamically unstable under decent pressure. To better understand the catalytic performance and enantioselectivity of HengPNP(L), its corresponding Ir(III) complex was employed in the asymmetric hydrogenation of various ketone substrates. A C-H bond activation Ir(III) compound was successfully isolated. The Ir(III)/HengPNP was efficient on the asymmetric hydrogenation of orthosubstituted benzophenones with excellent ee and up to 500 TON. The catalyst was superior on the hydrogenation of bis-ortho-substituted benzophenones, excellent ee was achieved over the state-of-the-art Ir/f-amphox. DFT studies was conducted to shed light on the enantio-induction model of Ir/HengPNP. A novel enantio-induction mechanism was established-the change of rotation energy of ketone substrate under the steric pressure from rigid Ir/HengPNP, was responsible for the enantioselectivity. IrH/NH bifunctional mechanism was proposed for this protocol.