The Synthesis And Application Of P N Ligands In Asymmetric Catalysis

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The Synthesis And Application Of P N Ligands In Asymmetric Catalysis

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Author : Dáiríne Morgan
language : en
Publisher:
Release Date : 2024

The Synthesis And Application Of P N Ligands In Asymmetric Catalysis written by Dáiríne Morgan and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2024 with Asymmetric synthesis categories.

Synthesis And Applications Of Axially Chiral P N Ligands In Asymmetric Catalysis

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Author : James Barker
language : en
Publisher:
Release Date : 2022

Synthesis And Applications Of Axially Chiral P N Ligands In Asymmetric Catalysis written by James Barker and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2022 with categories.

The Synthesis Of Chiral P N Ligands And Their Applications In Asymmetric Catalysis

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Author : Cian Reid
language : en
Publisher:
Release Date : 2023

The Synthesis Of Chiral P N Ligands And Their Applications In Asymmetric Catalysis written by Cian Reid and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2023 with categories.

Synthesis Resolution And Application Of Electronically Varied Axially Chiral P N Ligands In Asymmetric Catalysis

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Author : Kieran Connole
language : en
Publisher:
Release Date : 2016

Synthesis Resolution And Application Of Electronically Varied Axially Chiral P N Ligands In Asymmetric Catalysis written by Kieran Connole and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2016 with Catalysis categories.

The Synthesis And Application Of Bulky S Stereogenic And P Stereogenic Chiral Ligands

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Author : Seán Doran
language : en
Publisher:
Release Date : 2012

The Synthesis And Application Of Bulky S Stereogenic And P Stereogenic Chiral Ligands written by Seán Doran and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2012 with categories.

This doctoral thesis was focused on the design and synthesis of novel chiral ligands for application in asymmetric catalysis. One of the best examples of asymmetric catalysis is the asymmetric hydrogenation reaction for its atom economy, ease of access to both S and R enantiomers and almost ultimate enantiomeric excess obtainable in a multitude of substrates. There has been much investigation into this reaction and there has been a plethora of chiral ligands designed which catalyze this reaction in high enantiomeric excess using metals such as rhodium, iridium and ruthenium. The vast majority of these ligands are diphosphines with their chirality lying either on the backbone of the ligand or on the coordinating phosphorus atom itself. In the beginning of this work investigation was undertook to explore the possibility of successfully employing a new type of ligand class in the asymmetric hydrogenation reaction, namely the N-phosphino sulfinamide or PNSO ligands. PNSO ligands had been successfully applied to the asymmetric Pauson-Khand reaction in the Riera group yielding cyclopentenone Pauson-Khand adducts in high yield and very high enantioselectivity. The family of PNSO ligands prepared in the Riera group was attractive because apart from the high yields and enantioselectivities obtained from the reactions in which they were used, they proved to be easily prepared in short syntheses from commercially available starting materials. It was believed if they could be successfully applied in asymmetric hydrogenation for their ease of preparation they would be an attractive alternative to the diphosphine ligand class. Unfortunately the first two PNSO-Rh complexes successfully prepared provided low enantioselectivities and difficulties were encountered while trying to prepare further analogues. After some time trying to achieve PNSO-Rh complex analogues unsuccessfully the direction of the project was shifted away from the N-phosphino sulfinamide ligand class in asymmetric hydrogenation. The MaxPhos ligand had recently been developed in the group and had proven highly promising. A study was demanded of its substrate scope as applied in rhodium catalyzed asymmetric hydrogenation. Substrates already described in the literature were prepared and the asymmetric hydrogenation of them catalyzed by the MaxPhos-Rh precatalyst was performed and conditions to do so were optimized. Of seven substrates prepared the MaxPhos-Rh proved to hydrogenate five of those with high enantioselectivity. The TOF of the MaxPhos rhodium catalyst applied in the hydrogenation of the Z-MAC substrate was examined by monitoring the flux of hydrogen and was calculated at 0.065 s-1. MaxPhos complexes of cobalt and palladium were prepared to form part of the investigation into widening the reaction scope of the ligand. [(MaxPhos)Co2(CO)4(C2H2)] proved to catalyze the Pauson-Khand reaction of norbornadiene and 1-hexyne with 24 % yield and 28 %, a noteworthy enantiomeric excess for the catalytic asymmetric Pauson-Khand reaction. Chalcogenated derivatives of MaxPhos were prepared. The diselenide was used to explore the electronic nature of the ligand. The MaxPhos-rhodium carbonyl stretching was examined. MaxPhos-BH3 was used to prepare mono-chalcogenated MaxPhos derivatives. They were applied also in asymmetric hydrogenation once complexed to rhodium but enantiomeric excess of no more than 21 % was obtained in the hydrogenation of the substrate Z-MAC. The aminophosphine, a chiral building block and key intermediate in the preparation of the MaxPhos ligand, was used in the attempt to prepare bulky chiral amidine ligands and although two such species were prepared they proved inapplicable in asymmetric catalysis.

Chiral Pyridine Containing Ligands For Asymmetric Catalysis

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Author :
language : en
Publisher:
Release Date : 2003

Chiral Pyridine Containing Ligands For Asymmetric Catalysis written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2003 with categories.

Chiral Ligands

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Author : Montserrat Diéguez
language : en
Publisher: CRC Press
Release Date : 2021-05-13

Chiral Ligands written by Montserrat Diéguez and has been published by CRC Press this book supported file pdf, txt, epub, kindle and other format this book has been release on 2021-05-13 with Science categories.

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

Synthesis Of Aziridine Derived P N Ligands For Asymmetric Catalysis Microform

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Author : Shadi Dalili
language : en
Publisher: National Library of Canada = Bibliothèque nationale du Canada
Release Date : 2002

Synthesis Of Aziridine Derived P N Ligands For Asymmetric Catalysis Microform written by Shadi Dalili and has been published by National Library of Canada = Bibliothèque nationale du Canada this book supported file pdf, txt, epub, kindle and other format this book has been release on 2002 with categories.

Design Synthesis And Evaluation Of Chiral Nonracemic Ligands And Catalysts For Asymmetric Synthesis

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Author : Michael P. A. Lyle
language : en
Publisher:
Release Date : 2005

Design Synthesis And Evaluation Of Chiral Nonracemic Ligands And Catalysts For Asymmetric Synthesis written by Michael P. A. Lyle and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2005 with Asymmetric synthesis categories.

The work described in this thesis concerns the design, synthesis and evaluation of new chiral nonracemic ligands and catalysts for use in asymmetric reactions. A series of chiral nonracemic chloroacetals were prepared from 2-chloro-4- methyl-6,7-dihydro-5H-[l]pyrindine-7-one and a variety of C2-symmetric and chiral nonracemic 1,2-ethanediols (R = Me, i-Pr and Ph). These chloroacetals were further elaborated, in a modular fashion, to provide a series of chiral ligands and catalysts. A new class of C2-symmetric 2,2'-bipyridyl ligands were prepared in one step fiom the chloroacetals via a nickel(0)-mediated homo-coupling reaction. These ligands were then evaluated as chiral directors in copper@)-catalyzed asymmetric cyclopropanation reactions of styrene and diazoesters (up to 44% ee). A chiral pyridine N-oxide and a C2-symmetric 2,2'-bipyridyl N, N'-dioxide were also prepared by direct oxidation of the corresponding pyridine and the 2,2'-bipyridine, respectively. These chiral N-oxides were evaluated as chiral catalysts in desymmeterization reactions of cis-stilbene oxide (up to 20% ee). A series of pyridylphosphine ligands (P, N-ligands) were subsequently prepared in two steps from the chloroacetals via a Suzuki coupling reaction with orthofluorophenylboronic and on subsequent displacement of the fluoride with the potassium anion of diphenylphosphine. These ligands were then evaluated in palladium-catalyzed asymmetric allylic substitution reactions of racemic 3-acetoxy-l,3-diphenyl-1-propene with dimethyl malonate. Optimization of the reaction conditions resulted in the formation of the alkylated product in excellent yield (91%) and in high enantiomeric excess (90%). A related chiral nonracemic and C2-symmetric 2,2'-bipyridyl ligand was prepared from 2-chloro-4-methyl-5H-[llpyrindine. This pyrindine was prepared from a common intermediate that was used in the synthesis of the first generation of ligands. The chirality of this second generation ligand was installed by a Sharpless asymmetric dihydroxylation reaction (90% ee). The subsequently elaborated 2,2'-bipyridyl ligand (enriched to>99% ee) was then evaluated in copper(1)-catalyzed asymmetric cyclopropanation reactions of alkenes and diazoesters. In the case of the reaction of para-fluorostyrene and tert-butyl diazoacetate, the corresponding cyclopropane was formed in good diastereoselectivity (92:8) and in excellent enantioselectivity (99% ee). This ligand was also evaluated in copper(I1)-catalyzed asymmetric Friedel-Crafts alkylation reactions of various substituted indoles (up to 90% ee) and in copper(1)- catalyzed asymmetric allylic oxidation reactions of cyclic alkenes with tert-butyl peroxybenzoate (up to 9 1 % ee).

Synthesis Of Optically Pure Nitrogenated Ligands And Their Uses In Asymmetric Catalysis

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Author : Bilal El Asaad
language : en
Publisher:
Release Date : 2017

Synthesis Of Optically Pure Nitrogenated Ligands And Their Uses In Asymmetric Catalysis written by Bilal El Asaad and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2017 with categories.

New chiral N-arylated diamine ligands, derived from 1,2-diaminocyclohexane and a and ß-cyclic-aromatic ketone, were synthesized by dehydrogenative alkylation catalyzed by palladium on carbon (Pd/C). This method, allowed to prepare a series of chiral N,N-diarylated diamine and N-aryl diamine ligands with very good isolated yield.First of all, the applicability of the synthesized chiral diamine ligands was successfully examined in asymmetric transfer hydrogenation with homogeneous iridium catalyst associated to formic acid and its sodium salt. Various aromatic ketones were reduced to chiral alchohol with a complete conversion and high enantioselectivity (ee up to 93%). Then, two of the prepared chiral diamine, N,N'-dinaphtyl diaminocylohexane and N-naphtyl diaminocylohexane combined to copper (II), have been evaluated in asymmetric Henry reaction between benzaldehyde derivatives and nitromethane leading to ß-nitro-aryl-alcohol with good enantioselectivities (ee up to 83%) and good isolated yields.Furthermore, we transform these two ligands into imidazolinium salts precursor of carbenes, for further application in asymmetric catalysis. The mono N-arylated diamine was transformed into mono-thiourea ligand. These three new ligands were obtained with very good isolated yields.