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.

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

Phosphorus(III)Ligands in Homogeneous Catalysis

Phosphorus(III)Ligands in Homogeneous Catalysis
Author: Paul C. J. Kamer
Publisher: John Wiley & Sons
Total Pages: 673
Release: 2012-05-09
Genre: Technology & Engineering
ISBN: 1118299701

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Over the last 60 years the increasing knowledge of transition metal chemistry has resulted in an enormous advance of homogeneous catalysis as an essential tool in both academic and industrial fields. Remarkably, phosphorus(III) donor ligands have played an important role in several of the acknowledged catalytic reactions. The positive effects of phosphine ligands in transition metal homogeneous catalysis have contributed largely to the evolution of the field into an indispensable tool in organic synthesis and the industrial production of chemicals. This book aims to address the design and synthesis of a comprehensive compilation of P(III) ligands for homogeneous catalysis. It not only focuses on the well-known traditional ligands that have been explored by catalysis researchers, but also includes promising ligand types that have traditionally been ignored mainly because of their challenging synthesis. Topics covered include ligand effects in homogeneous catalysis and rational catalyst design, P-stereogenic ligands, calixarenes, supramolecular approaches, solid phase synthesis, biological approaches, and solubility and separation. Ligand families covered in this book include phosphine, diphosphine, phosphite, diphosphite, phosphoramidite, phosphonite, phosphinite, phosphole, phosphinine, phosphinidenene, phosphaalkenes, phosphaalkynes, P-chiral ligands, and cage ligands. Each ligand class is accompanied by detailed and reliable synthetic procedures. Often the rate limiting step in the application of ligands in catalysis is the synthesis of the ligands themselves, which can often be very challenging and time consuming. This book will provide helpful advice as to the accessibility of ligands as well as their synthesis, thereby allowing researchers to make a more informed choice. Phosphorus(III) Ligands in Homogeneous Catalysis: Design and Synthesis is an essential overview of this important class of catalysts for academic and industrial researchers working in catalyst development, organometallic and synthetic chemistry.

Lanthanides in Organic Synthesis

Lanthanides in Organic Synthesis
Author: Tsuneo Imamoto
Publisher:
Total Pages: 184
Release: 1994
Genre: Science
ISBN:

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Organic synthesis with lanthanides has experienced enormous growth in the last ten years. Numerous synthetic reactions have been explored by the use of lanthanide reagents, and some of these have become indispensablein modern organic synthesis. This book describes the remarkable scope and potential of these reagents, addressing this rapidly growing area from a practical point-of-view. The author has summarized synthetically useful and novel organic transformations, emphasizing the characteristic properties of lanthanide reagents. These transformations are concisely and skillfully presented in many schemes and tables, with actual illustrative preparations. The coverage includes the use of lanthanide metals, the powerful divalent reagents such as samarium (II) iodide, the key trivalent reagents and their particular role as catalysts in selective reductions and cycloadditions, and the tetravalent lanthanides as oxidants. Describes the remarkable scope and potential of lanthanide reagents from a practical point-of-view Presents actual experimental procedures Provides a concise presentation of useful and novel organic transformations in table format

Fundamentals of Asymmetric Catalysis

Fundamentals of Asymmetric Catalysis
Author: Patrick J. Walsh
Publisher: University Science Books
Total Pages: 692
Release: 2009-01-02
Genre: Science
ISBN: 9781891389542

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This work describes the essential aspects of enantioselective catalysis, with chapters organised by concept rather than by reaction type. Each concept is supported by examples to give the reader broad exposure to a wide range of catalysts, reactions and reaction mechanisms.

Development in Phosphorus Ligands and Their Applications in Rhodium-catalyzed Reactions

Development in Phosphorus Ligands and Their Applications in Rhodium-catalyzed Reactions
Author: Bonan Cao
Publisher:
Total Pages: 130
Release: 2013
Genre: Chirality
ISBN:

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Transition-metal-catalyzed reactions have become powerful tools in the production of pharmaceuticals and fine chemicals. In the past decades, asymmetric catalysis, especially chiral rhodium catalysts, hold an increasing role of efficiently building up chirality. In this dissertation, we will focus on the development of several rhodium phosphorus catalysts and their applications in hydroformylation and asymmetric hydrogenation reactions. Chapter I outlined the development of a new family of sterrically rigid hybrid phosphine-phosphoramidite ligands. The new catalyst system shows excellent compatibility versus styrene, vinyl acetate, allyl cyanide and their derivatives. The relationship between the enantioselectivity and the substituent on ligands is investigated by systematic variation on the ligand structures. In chapter II, further application of phosphine-phosphoramidite ligands in asymmetric hydroformylation of N-allylamides and N-allylsulfonamides provides a new approach to chiral [beta]2-amino aldehydes, acids, and alcohols for pharmaceutical and synthetic chemistry. Up to 99% ee and 9700 turnovers stands as the best result achieved in this type of hydroformylation reaction. Chapter III focuses on the synthesis of a series of aryl substituted dihydropyrroles via this hydroformylation. The significant improvement in reactivity and chemoselectivity suggests a potential application in building large heterocycles in an atom efficient fashion. In chapter IV, I report a successful monodentate phosphoramidite ligand for the catalytic asymmetric hydrogenation of dehydroamino esters. The easy modulared structure allowed us to further expand the scope of the ligand.

Phosphorus(iii) Ligands in Homogeneous Catalysis

Phosphorus(iii) Ligands in Homogeneous Catalysis
Author: Paul Kamer
Publisher: John Wiley & Sons
Total Pages:
Release: 2012-07-01
Genre: Catalysis
ISBN: 9781119943990

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Over the last 60 years the increasing knowledge of transition metal chemistry has resulted in an enormous advance of homogeneous catalysis as an essential tool in both academic and industrial fields. Remarkably, phosphorus(III) donor ligands have played an important role in several of the acknowledged catalytic reactions. The positive effects of phosphine ligands in transition metal homogeneous catalysis have contributed largely to the evolution of the field into an indispensable tool in organic synthesis and the industrial production of chemicals. This book aims to address the design and synthesis of a comprehensive compilation of P(III) ligands for homogeneous catalysis. It not only focuses on the well-known traditional ligands that have been explored by catalysis researchers, but also includes promising ligand types that have traditionally been ignored mainly because of their challenging synthesis. Topics covered include ligand effects in homogeneous catalysis and rational catalyst design, P-stereogenic ligands, calixarenes, supramolecular approaches, solid phase synthesis, biological approaches, and solubility and separation. Ligand families covered in this book include phosphine, diphosphine, phosphite, diphosphite, phosphoramidite, phosphonite, phosphinite, phosphole, phosphinine, phosphinidenene, phosphaalkenes, phosphaalkynes, P-chiral ligands, and cage ligands. Each ligand class is accompanied by detailed and reliable synthetic procedures. Often the rate limiting step in the application of ligands in catalysis is the synthesis of the ligands themselves, which can often be very challenging and time consuming. This book will provide helpful advice as to the accessibility of ligands as well as their synthesis, thereby allowing researchers to make a more informed choice. "Phosphorus(III) Ligands in Homogeneous Catalysis: Design and Synthesis" is an essential overview of this important class of catalysts for academic and industrial researchers working in catalyst development, organometallic and synthetic chemistry.