Chiral D4-symmetric Porphyrin and Pyridine-containing Ligands for Metal-catalyzed Asymmetric Reactions PDF Download
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Author: 丁鵬飛
Publisher:
ISBN:
Category : Asymmetric synthesis
Languages : en
Pages : 448
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Book Description
Author: 丁鵬飛
Publisher:
ISBN:
Category : Asymmetric synthesis
Languages : en
Pages : 448
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Book Description
Author: Junliang Zhang
Publisher: Elsevier
ISBN: 0323852262
Category : Science
Languages : en
Pages : 322
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Book Description
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
Author:
Publisher:
ISBN: 9789172835375
Category :
Languages : en
Pages : 68
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Author: Rui Zhang
Publisher: Open Dissertation Press
ISBN: 9781374698109
Category :
Languages : en
Pages :
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Book Description
This dissertation, "Asymmetric Organic Oxidation by Chiral Ruthenium Complexes Containing D2 and D4 Symmetric Porphyrinato Ligands" by Rui, Zhang, 張瑞, was obtained from The University of Hong Kong (Pokfulam, Hong Kong) and is being sold pursuant to Creative Commons: Attribution 3.0 Hong Kong License. The content of this dissertation has not been altered in any way. We have altered the formatting in order to facilitate the ease of printing and reading of the dissertation. All rights not granted by the above license are retained by the author. DOI: 10.5353/th_b4257624 Subjects: Ruthenium compounds - Oxidation Porphyrin and porphyrin compounds Ligands
Author: 周向葛
Publisher:
ISBN: 9781374789531
Category :
Languages : en
Pages :
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This dissertation, "Asymmetric Reactions Catalyzed by Transition Metal Complexes Containing Binaphthyl Schiff Bases and Chiral Porphyrinato Ligands" by 周向葛, Xiangge, Zhou, was obtained from The University of Hong Kong (Pokfulam, Hong Kong) and is being sold pursuant to Creative Commons: Attribution 3.0 Hong Kong License. The content of this dissertation has not been altered in any way. We have altered the formatting in order to facilitate the ease of printing and reading of the dissertation. All rights not granted by the above license are retained by the author. DOI: 10.5353/th_b3123983 Subjects: Perylene Schiff bases Porphyrins Ligands Catalysis
Author: Wei Li
Publisher:
ISBN:
Category :
Languages : en
Pages : 233
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Author: Roger Guilard
Publisher: Elsevier
ISBN: 0080923852
Category : Science
Languages : en
Pages : 321
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Book Description
The Porphyrin Handbook, Volume 11: Bioinorganic and Bioorganic Chemistry presents the fundamental aspects of the synthesis, structure, chemistry, and spectroscopy of phthalocyanines. This book discusses the biology and medical implications of porphyrin systems. Organized into seven chapters, this volume begins with an overview of the design, synthesis, and study of the structural and functional models of heme/copper terminal oxidases. This text then examines the proteins containing iron-protoporphyrin IX (heme), which play key roles in photosynthesis and respiration. Other chapters consider the syntheses of chiral porphyrin derivatives and summarize the uses of such compounds in enantioselective control. This book discusses as well the reactivity and synthesis of synthetic carbine metalloporphyrins. The final chapter deals with the B12-coenzymes, which is the most complex and physiologically important organometallic enzymatic reactions that directly depend on the reactivity of metal coordinated organic ligands. This book is a valuable resource for research scientists, clinicians, and engineers.
Author: Kenneth Wärnmark
Publisher:
ISBN:
Category :
Languages : en
Pages : 88
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Author: Xiangge Zhou
Publisher:
ISBN:
Category : Catalysis
Languages : en
Pages : 426
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Author: Zhiming Xu
Publisher:
ISBN:
Category :
Languages : en
Pages : 332
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Book Description
Chapter 1. Effect of linker length on selectivity and cooperative reactivity in platinum-catalyzed asymmetric alkylation of bis(phenylphosphino)alkanes. The selectivity of catalytic asymmetric transformations of bifunctional symmetrical substrates often depends on the linker between the two reactive sites. If the catalyst controls the selectivity of reactions at both sites, the rac product will be formed in high enantiomeric ratio (er) via asymmetric amplification. Substrate control may augment this selectivity (positive cooperativity) or detract from it (negative cooperativity). We investigated the effect of linker length on the selectivity of catalytic asymmetric alkylation of the bis(secondary phosphines) PhHP-(CH2)[subscript n]PHPh (n = 2-6, 1a-e) with benzyl bromide using the base NaOSiMe3 and the catalyst precursor Pt((R,R)-Me-DuPhos)(Ph)(Cl). The two alkylations of bis(secondary phosphines) 1b-e with longer linker lengths (n = 3-6) showed identical selectivity, within experimental error. This catalyst control resulted in asymmetric amplification of rac-2. In contrast, the selectivity of the first alkylation of ethano-bridged 1a was lower than that in 1b-e (negative cooperativity), but the selectivity of the second alkylation increased due to positive cooperativity. I developed an efficient synthesis of the intermediate PhHP(CH2)2PPh(CH2Ph) (3a), which was required for determination of the selectivity of both steps in Pt-catalyzed alkylation of 1a. Possible mechanistic explanations for the observed dependence of selectivity on linker length are discussed in this chapter. Chapter 2. Selective formation of a C3-symmetric P-stereogenic tris(phosphine) via platinum-catalyzed asymmetric alkylation of a tris(secondary phosphine). C2-symmetric bis(phosphines) are the most common and successful ligands for metal-catalyzed reactions. Considering the great success of C2-symmetric ligands in asymmetric catalysis, C3-symmetric chiral tris(phosphines) were proposed to be useful in octahedral complexes, creating three homotopic sites. However, very little is known about C3-symmetric tris(phosphines) and their applications, mostly because of the lack of synthetic routes. We used Pt-catalyzed asymmetric alkylation to prepare enantiomerically enriched C3-symmetric, P-stereogenic tripodal tris(phosphines) from the tris(secondary phosphine) MeC(CH2PHPh)3 (5 a racemic mixture of C1- and C3-symmetric diastereomers) and a benzl bromide, utilizing the Pt((R,R)-Me-Duphos)(Ph)(Cl) catalyst precursor and a base. Pt-catalyzed alkylation of MeC(CH2PHPh)3 (5) with 2-cyanobenzyl bromide gave a mixture of tris(phosphines) MeC(CH2PPh(CH2Ar))3 (6) enriched in C3-6; oxidation of 6 by sulfur or H2O2 formed phosphine sulfide S-6 and oxide O-6. Hydrogen bonding between O-6 and the chiral amino acid (S)-Fmoc-Trip(BOC)-OH leads to the formation of new diastereomers. By integrating the 31P NMR spectra, I measured the dr and er values. Tris(phosphine) 6 was formed with a disatereomeric ratio (dr - C3/C1) of 2.1(2) and enantiomeric ratios of 54(10) and 3.8(7) for C3-3 and C1-3 respectively, which showed that the selectivity of the triple alkylation was not the same at each site (substrate control). Chapter 3. Screening racemic catalysts provides information on selectivity and mechanism in platinum-mediated asymmetric alkylation of bis- and tris(secondary phosphines). Screening racemic catalysts for transformations of symmetrical bifunctional substrates can provide information on the selectivity of an enantiopure catalyst. This idea was extended to Pt-catalyzed asymmetric alkylation of the bis(secondary phosphines) PhHP(CH2)3PHPh and PhHPCH2CMe2CH2PHPh and the tris(phosphine) MeC(CH2PHPh)3 with benzyl bromides using the catalyst precursors Pt(Me-DuPhos)(Ph)(CI) and Pt(BenzP*)(Ph)(CI). Depending on the catalyst and the substrate, these reactions occured under catalyst control without dissociation of the substrate, or under substrate control with or without substrate dissociation. The resulting structure-selectivity relationships provided mechanistic information. Chapter 4. Synthesis of new chiral bis(phospholane) metal-pincer complexes. Metal pincer complexes have received great attention in recent years as robust catalyst precursors. However, chiral metal pincer complexes for application in asymmetric catalysis are rare. Dialkylphospholane groups have an outstanding track record in asymmetric catalysis (commercial DuPhos and BPE ligands) and their steric properties can be easily controlled by tuning the alkyl substituents on the phospholane ring. These donors have similar steric and electronic properties to the common used bulky dialkylphosphine groups (P(t-Bu)2, P(i-Pr)2, etc.). Optimization of the synthesis of chiral PCP ligands bearing such phospholane groups and investigation of their coordination chemistry are discussed in this chapter.
