New Chiral N-heterocyclic Carbene-imine Ligands and Their Application to Asymmetric Catalysis

New Chiral N-heterocyclic Carbene-imine Ligands and Their Application to Asymmetric Catalysis PDF Author: Ludovic Grkegoire Bonnet
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Languages : en
Pages :

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New Chiral N-heterocyclic Carbene-imine Ligands and Their Application to Asymmetric Catalysis

New Chiral N-heterocyclic Carbene-imine Ligands and Their Application to Asymmetric Catalysis PDF Author: Ludovic Grkegoire Bonnet
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Chiral Ferrocenes in Asymmetric Catalysis

Chiral Ferrocenes in Asymmetric Catalysis PDF Author: Li-Xin Dai
Publisher: John Wiley & Sons
ISBN: 3527322809
Category : Science
Languages : en
Pages : 433

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Book Description
This book meets the long-felt need for a reference on ferrocenes with the focus on catalysis. It provides a thorough overview of the synthesis and characterization of different types of chiral ferrocene ligands, their application to various catalytic asymmetric reactions, and versatile chiral materials as well as drug intermediates synthesized from them. Written by the "who's who" of ferrocene catalysis, this is a guide to the design of new ferrocene ligands and synthesis of chiral synthetic intermediates, and will thus be useful for organic, catalytic and synthetic chemists working in academia, industrial research or process development.

N-Heterocyclic Carbenes in Organocatalysis

N-Heterocyclic Carbenes in Organocatalysis PDF Author: Akkattu T. Biju
Publisher: John Wiley & Sons
ISBN: 3527809058
Category : Science
Languages : en
Pages : 440

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Book Description
Summarizing the emerging field of N-heterocyclic carbenes used in organocatalysis, this is an excellent overview of the synthesis and applications of NHCs focusing on carbon-carbon and carbon-heteroatom bond formation. Alongside comprehensive coverage of the synthesis, characteristics and applications, this handbook and ready reference also includes chapters on NHCs for polymerization reactions and natural product synthesis.

N-Heterocyclic Carbenes in Synthesis

N-Heterocyclic Carbenes in Synthesis PDF Author: Steven P. Nolan
Publisher: John Wiley & Sons
ISBN: 9783527314003
Category : Science
Languages : en
Pages : 330

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Book Description
This first handbook to focus solely on the application of N-heterocyclic carbenes in synthesis covers metathesis, organocatalysis, oxidation and asymmetric reactions, along with experimental procedures. Written by leading international experts this is a valuable and practical source for every organic chemist.

Chiral Ligands

Chiral Ligands PDF Author: Montserrat Diéguez
Publisher: CRC Press
ISBN: 1000379000
Category : Science
Languages : en
Pages : 298

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Book Description
Many new drugs on the market are chiral compounds, that is, they can exist in two non-superimposable mirror-image forms. Asymmetric catalysis encompasses a large variety of processes for obtaining such compounds. The performance of the catalyst in those processes largely depends on the ligand that makes up the catalyst. This book describes the most relevant ligand libraries for some key processes, including an overview of the state of art and the key mechanistic aspects that favor a high catalytic performance. Key Features: The book presents historical content from the time of discovery for each family of ligands. Provides a description of the synthetic route and the ligand library's application in various catalytic asymmetric reactions Suitable as supplementary reading for courses targeting the design, synthesis and application of chiral catalysts, asymmetric catalysis and sustainable production Edited by a distinguished scientist in the field, the book has a diverse audience including research groups in homogeneous catalysis, particularly asymmetric transformations

New Chiral Di-n-heterocyclic Carbene Ligands and Their Application in Enantioselective Hydrogenation, Hydroformylation and 1,4-conjugate Addition Reactions. a Study Toward Rational Development of Di-n-heterocyclic Carbene Complexes in Enantioselective Catalysis

New Chiral Di-n-heterocyclic Carbene Ligands and Their Application in Enantioselective Hydrogenation, Hydroformylation and 1,4-conjugate Addition Reactions. a Study Toward Rational Development of Di-n-heterocyclic Carbene Complexes in Enantioselective Catalysis PDF Author: Matthew Stephen Jeletic
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Category :
Languages : en
Pages :

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Book Description
We finally present catalytic hydrogenation, hydrogen transfer, hydrosilylation, hydroformylation and 1,4-conjugate addition reactions. The % e.e. for hydrogenation ranged from 0-10%. for the reactions involving hydrogen. These results are attributable to either reductive elimination of the diNHC from the metal center, high temperatures necessary to achieve reaction conversion, or the inherent flexibility of the DEAM ligands. The Pd(diNHC) complexes achieved better selectivity in 1,4-conjugate addition reactions (0-67% e.e.).

N-Heterocyclic Carbenes

N-Heterocyclic Carbenes PDF Author: Silvia Diez-Gonzalez
Publisher: Royal Society of Chemistry
ISBN: 1782624236
Category : Science
Languages : en
Pages : 636

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Book Description
In less than 20 years N-heterocyclic carbenes (NHCs) have become well-established ancillary ligands for the preparation of transition metal-based catalysts. This is mainly due to the fact that NHCs tend to bind strongly to metal centres, avoiding the need of excess ligand in catalytic reactions. Also, NHC‒metal complexes are often insensitive to air and moisture, and have proven remarkably resistant to oxidation. This book showcases the wide variety of applications of NHCs in different chemistry fields beyond being simple phosphine mimics. This second edition has been updated throughout, and now includes a new chapter on NHC‒main group element complexes. It covers the synthesis of NHC ligands and their corresponding metal complexes, as well as their bonding and stereoelectronic properties and applications in catalysis. This is complemented by related topics such as organocatalysis and biologically active complexes. Written for organic and inorganic chemists, this book is ideal for postgraduates, researchers and industrialists.

N-Heterocyclic Carbenes in Organocatalysis

N-Heterocyclic Carbenes in Organocatalysis PDF Author: Akkattu T. Biju
Publisher: John Wiley & Sons
ISBN: 3527343105
Category : Science
Languages : en
Pages : 436

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Book Description
Summarizing the emerging field of N-heterocyclic carbenes used in organocatalysis, this is an excellent overview of the synthesis and applications of NHCs focusing on carbon-carbon and carbon-heteroatom bond formation. Alongside comprehensive coverage of the synthesis, characteristics and applications, this handbook and ready reference also includes chapters on NHCs for polymerization reactions and natural product synthesis.

Chiral Sulfur Ligands

Chiral Sulfur Ligands PDF Author: Hélène Pellissier
Publisher: Royal Society of Chemistry
ISBN: 1847559247
Category : Science
Languages : en
Pages : 403

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Book Description
The goal of this book is to show the high potential of chiral sulfur-containing ligands to promote numerous asymmetric catalytic transformations. These ligands can now be recognised as real competitors to the more usual phosphorus- or nitrogen-containing ligands.

Chiral Donor-Functionalized N-Heterocyclic Carbenes for Asymmetric Catalytic Applications in Hydrogenation - From Design to Application

Chiral Donor-Functionalized N-Heterocyclic Carbenes for Asymmetric Catalytic Applications in Hydrogenation - From Design to Application PDF Author: Kai Yang Wan
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

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Book Description
In this thesis, the synthetic protocol for a new class of enantiopure, primary-amine tethered N-heterocyclic carbene (NHC) ligands is described. The synthesis, coordination chemistry, and applications in catalysis for three ligands from this class with general formula (S,S)/(R,R)-H2N-CHPh-CHPh-NHC (NHC = -NCHCHN(C)R, R = Me, tBu, or Mes) are reported. The imidazolium salt of these ligands can be prepared in high yield and purity from the SN1 reaction between chiral sulfamidates and the corresponding N-substituted imidazoles. The method of coordination of the NHC ligands to metals depends on the acidity of the C-H functional in the imidazolium salts. Silver and copper compounds can be prepared in high yield with the ligand to the metal ratio of 2:1 or 1:1. Ruthenium, iridium, and rhodium complexes can also be prepared via transmetallation from the silver or copper reagents, intramolecular base deprotonation, or C-H oxidative addition. Four ruthenium complexes and two iridium complexes based on these ligands were proven active for ketone hydrogenation, under relatively mild condition (50°C, 25 bar H2(g)). Three half-sandwich ruthenium compounds containing Cp (cyclopentadienyl) or Cp* (1,2,3,4,5-pentamethylcyclopentadienyl) are highly active aryl and alkyl hydrogenation catalysts with TOF (turnover frequency) up to 67 s-1, TON (turnover number) up to 104, and ee (enantiomeric excess) up to 86%. An experimental and computational study of the half-sandwich ruthenium systems suggests that the heterolytic splitting of dihydrogen over the metal-amido bond and hydride transfer from the catalyst to the substrate can both be rate-determining. An alcohol-assisted mechanism was also calculated to explain the rate enhancement when the catalysis was conducted in polar, protic solvents such as 2-PrOH. A full experimental and computational study was also performed for a Fe(P-NH-P') system. Similarly, heterolytic splitting and hydride transfer are the two most energy demanding transition states. In addition, the enantiodetermining step (EDS) of this asymmetric ketone hydrogenation catalyst was calculated, and the origins of enantioselectivity were summarized as steric repulsion, the high compressibility of the backbone, and H-bond contributed stabilization.