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Book New Chiral Rhodium II Catalysts for Asymmetric Synthesis with A diazocarbonyl Substrates

Download or read book New Chiral Rhodium II Catalysts for Asymmetric Synthesis with A diazocarbonyl Substrates written by Nicolas François Marie Pierson and published by . This book was released on 1998 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Asymmetric Synthesis in Insertion Reactions of alpha Diazocarbonyl Compounds Catalysed by Chiral Rhodium II Carboxylates

Download or read book Asymmetric Synthesis in Insertion Reactions of alpha Diazocarbonyl Compounds Catalysed by Chiral Rhodium II Carboxylates written by Kevin Michael Lydon and published by . This book was released on 1999 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Rhodium Catalysis in Organic Synthesis

Download or read book Rhodium Catalysis in Organic Synthesis written by Ken Tanaka and published by John Wiley & Sons. This book was released on 2019-05-06 with total page 684 pages. Available in PDF, EPUB and Kindle. Book excerpt: An essential reference to the highly effective reactions applied to modern organic synthesis Rhodium complexes are one of the most important transition metals for organic synthesis due to their ability to catalyze a variety of useful transformations. Rhodium Catalysis in Organic Synthesis explores the most recent progress and new developments in the field of catalytic cyclization reactions using rhodium(I) complexes and catalytic carbon-hydrogen bond activation reactions using rhodium(II) and rhodium(III) complexes. Edited by a noted expert in the field with contributions from a panel of leading international scientists, Rhodium Catalysis in Organic Synthesis presents the essential information in one comprehensive volume. Designed to be an accessible resource, the book is arranged by different reaction types. All the chapters provide insight into each transformation and include information on the history, selectivity, scope, mechanism, and application. In addition, the chapters offer a summary and outlook of each transformation. This important resource: -Offers a comprehensive review of how rhodium complexes catalyze a variety of highly useful reactions for organic synthesis (e.g. coupling reactions, CH-bond functionalization, hydroformylation, cyclization reactions and others) -Includes information on the most recent developments that contain a range of new, efficient, elegant, reliable and useful reactions -Presents a volume edited by one of the international leading scientists working in the field today -Contains the information that can be applied by researchers in academia and also professionals in pharmaceutical, agrochemical and fine chemical companies Written for academics and synthetic chemists working with organometallics, Rhodium Catalysis in Organic Synthesis contains the most recent information available on the developments and applications in the field of catalytic cyclization reactions using rhodium complexes.

Book Rhodium Catalyzed Hydroformylation

Download or read book Rhodium Catalyzed Hydroformylation written by Piet W.N.M. van Leeuwen and published by Springer Science & Business Media. This book was released on 2006-04-11 with total page 291 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the last decade there have been numerous advances in the area of rhodium-catalyzed hydroformylation, such as highly selective catalysts of industrial importance, new insights into mechanisms of the reaction, very selective asymmetric catalysts, in situ characterization and application to organic synthesis. The views on hydroformylation which still prevail in the current textbooks have become obsolete in several respects. Therefore, it was felt timely to collect these advances in a book. The book contains a series of chapters discussing several rhodium systems arranged according to ligand type, including asymmetric ligands, a chapter on applications in organic chemistry, a chapter on modern processes and separations, and a chapter on catalyst preparation and laboratory techniques. This book concentrates on highlights, rather than a concise review mentioning all articles in just one line. The book aims at an audience of advanced students, experts in the field, and scientists from related fields. The didactic approach also makes it useful as a guide for an advanced course.

Book Asymmetric Metal Catalysis in Enantioselective Domino Reactions

Download or read book Asymmetric Metal Catalysis in Enantioselective Domino Reactions written by Helene Pellissier and published by John Wiley & Sons. This book was released on 2019-07-12 with total page 342 pages. Available in PDF, EPUB and Kindle. Book excerpt: Introduces an innovative and outstanding tool for the easy synthesis of complex chiral structures in a single step Covering all of the literature since the beginning of 2006, this must-have book for chemists collects the major progress in the field of enantioselective one-, two-, and multicomponent domino reactions promoted by chiral metal catalysts. It clearly illustrates how enantioselective metal-catalyzed processes constitute outstanding tools for the development of a wide variety of fascinating one-pot asymmetric domino reactions, thereby allowing many complex products to be easily generated from simple materials in one step. The book also strictly follows the definition of domino reactions by Tietze as single-, two-, as well as multicomponent transformations. Asymmetric Metal Catalysis in Enantioselective Domino Reactions is divided into twelve chapters, dealing with enantioselective copper-, palladium-, rhodium-, scandium-, silver-, nickel-, gold-, magnesium-, cobalt-, zinc-, yttrium and ytterbium-, and other metal-catalyzed domino reactions. Most of the chapters are divided into two parts dealing successively with one- and two-component domino reactions, and three-component processes. Each part is subdivided according to the nature of domino reactions. Each chapter of the book includes selected applications of synthetic methodologies to prepare natural and biologically active products. -Presents the novel combination of asymmetric metal catalysis with the concept of fascinating domino reactions, which allows high molecular complexity with a remarkable level of enantioselectivity -Showcases an incredible tool synthesizing complex and diverse chiral structures in a single reaction step -Includes applications in total synthesis of natural products and biologically active compounds -Written by a renowned international specialist in the field -Stimulates the design of novel asymmetric domino reactions and their use in the synthesis of natural products, pharmaceuticals, agrochemicals, and materials Asymmetric Metal Catalysis in Enantioselective Domino Reactions will be of high interest to synthetic, organic, medicinal, and catalytic chemists in academia and R&D departments.

Book Modern Rhodium Catalyzed Organic Reactions

Download or read book Modern Rhodium Catalyzed Organic Reactions written by P. Andrew Evans and published by Wiley-VCH. This book was released on 2006-03-06 with total page 496 pages. Available in PDF, EPUB and Kindle. Book excerpt: Rhodium has proven to be an extremely useful metal due to its ability to catalyze an array of synthetic transformations, with quite often-unique selectivity. Hydrogenation, C-H activation, allylic substitution, and numerous other reactions are catalyzed by this metal, which presumably accounts for the dramatic increase in the number of articles that have recently emerged on the topic. P. Andrew Evans, the editor of this much-needed book, has assembled an internationally renowned team to present the first comprehensive coverage of this important area. The book features contributions from leaders in the field of rhodium-catalyzed reactions, and thereby provides a detailed account of the most current developments, including: Rhodium-Catalyzed Asymmetric Hydrogenation (Zhang) Rhodium-Catalyzed Hydroborations and Related Reactions (Brown) Rhodium-Catalyzed Asymmetric Addition of Organometallic Reagents to Electron Deficient Olefins (Hayashi) Recent Advances in Rhodium(I)-Catalyzed Asymmetric Olefin Isomerization and Hydroacylation Reactions (Fu) Stereoselective Rhodium(I)-Catalyzed Hydroformylation and Silylformylation Reactions and Their Application to Organic Synthesis (Leighton) Carbon-Carbon Bond-Forming Reactions Starting from Rh-H or Rh-Si Species (Matsuda) Rhodium(I)-Catalyzed Cycloisomerization and Cyclotrimerization Reactions (Ojima) The Rhodium(I)-Catalyzed Alder-ene Reaction (Brummond) Rhodium-Catalyzed Nucleophilic Ring Cleaving Reactions of Allylic Ethers and Amines (Fagnou) Rhodium(I)-Catalyzed Allylic Substitution Reactions and their Applications to Target Directed Synthesis (Evans) Rhodium(I)-Catalyzed [2+2+1] and [4+1] Carbocyclization Reactions (Jeong) Rhodium(I)-Catalyzed [4+2] and [4+2+2] Carbocyclizations (Robinson) Rhodium(I)-Catalyzed [5+2], [6+2], and [5+2+1] Cycloadditions: New Reactions for Organic Synthesis (Wender) Rhodium(II)-Stabilized Carbenoids Containing both Donor and Acceptor Substituents (Davies) Chiral Dirhodium(II)Carboxamidates for Asymmetric Cyclopropanation and Carbon-Hydrogen Insertion Reactions (Doyle) Cyclopentane Construction by Rhodium(II)-Mediated Intramolecular C-H Insertion (Taber) Rhodium(II)-Catalyzed Oxidative Amination (DuBois) Rearrangement Processes of Oxonium and Ammonium Ylides Formed by Rhodium(II)-Catalyzed Carbene-Transfer (West) Rhodium(II)-Catalyzed 1,3-Dipolar Cycloaddition Reactions (Austin) "Modern Rhodium-Catalyzed Organic Reactions" is an essential reference text for researchers at all levels in the general area of organic chemistry. This book provides an invaluable overview of the most significant developments in this important area of research, and will no doubt be an essential text for researchers at academic institutions and professionals at pharmaceutical/agrochemical companies.

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

Download or read book Synthesis and Application of New Chiral Ligands for Enantioselectivity Tuning in Transition Metal Catalysis written by Fanji Kong and published by . This book was released on 2017 with total page 156 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Book Novel Chiral Rhodium II Carboxylates as Catalysts in Asymmetric Cyclopropanations

Download or read book Novel Chiral Rhodium II Carboxylates as Catalysts in Asymmetric Cyclopropanations written by Paul Richard Bruzinski and published by . This book was released on 1997 with total page 584 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book New Catalysts for Asymmetric Nitrene Transfer Based on Ion pairing Between Sulfonated Rhodium II II Tetracarboxylates and Chiral Cations

Download or read book New Catalysts for Asymmetric Nitrene Transfer Based on Ion pairing Between Sulfonated Rhodium II II Tetracarboxylates and Chiral Cations written by Alexander Fanourakis and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Applied Asymmetric Hydroformylation with Rhodium bisdiazaphospholane Catalysts

Download or read book Applied Asymmetric Hydroformylation with Rhodium bisdiazaphospholane Catalysts written by and published by . This book was released on 2014 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The conversion of olefins into aldehydes by hydroformylation with rhodium catalysts is one of the largest homogeneously catalyzed industrial reactions, producing millions of tons of linear aldehydes per year. However, the production of chiral, branched aldehydes via asymmetric hydroformylation (AHF) remains underutilized in synthesis. To improve the application of rhodium BisDiazaphos catalyzed AHF, high selectivity for previously uninvestigated disubstituted olefins including enol esters and enamides is demonstrated, which yield more complex [alpha]-functionalized aldehyde building blocks. Additionally, process-scale asymmetric hydroformylation to yield chiral, enantioenriched aldehyde feedstocks has not yet been demonstrated. In collaboration with Eli Lilly, asymmetric hydroformylation in a research scale flow reactor is realized through the development of a flow synthesis of naproxen. To support scale-up of asymmetric hydroformylation technologies the synthesis of bisdiazaphospholane ligands is re-examined to optimize the cost of the material and synthesis on a larger scale is demonstrated. Access to enantiopure ligand via classical resolution in place of preparative SFC chromatography has also been developed, and will improve accessibility to selective AHF catalysts. Finally, the direct observation of catalytic intermediates and rate information in asymmetric hydroformylation by circulating high-pressure NMR will be described.

Book C2 and C3 Symmetric Chiral Bis and Tris phosphines in Asymmetric Catalysis

Download or read book C2 and C3 Symmetric Chiral Bis and Tris phosphines in Asymmetric Catalysis written by Zhiming Xu and published by . This book was released on 2017 with total page 332 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Book Applications of Chiral Aluminum and Boron Catalysts in Asymmetric Synthesis

Download or read book Applications of Chiral Aluminum and Boron Catalysts in Asymmetric Synthesis written by Li Zheng and published by . This book was released on 2020 with total page 271 pages. Available in PDF, EPUB and Kindle. Book excerpt: A potent chiral aluminum catalyst has been developed for asymmetric MPV reduction of ketones with broad substrate scope and excellent yields and enantiomeric inductions. The catalyst consists an aluminum core, a VANOL-derived chiral ligand and an isopropoxy group. Different ligands have been screened and reaction parameters have been optimized. A variety of aromatic (both electron-poor and electron-rich) and aliphatic ketones were converted to chiral alcohols in good yields with high enantioselectivities (26 examples, 70-98% yield and 82-99% ee). This method operates under mild conditions (-10 °C) and low catalyst loading (1-10 mol%). Furthermore, this process is catalyzed by the earth-abundant main group element aluminum and employs inexpensive and environmentally benign 2-propanol as hydride source. This catalyst has also been employed in resolution of racemic alcohols. The kinetic resolution of alcohols by Oppenauer oxidation has been achieved with moderate results. The formal dynamic kinetic resolution via Oppenauer oxidation/ MPV reduction sequence has also been examined and discussed, which avoided acylation and the use of enzymes.A highly efficient asymmetric heteroatom Diels-Alder reaction between diene and aldehydes for the construction of 6-membered heterocycles catalyzed by chiral boron catalysts has been developed. A BINOL-derived propeller borate is found to be effective catalyzing the reaction of aromatic aldehydes. A VANOL-derived meso-borate is found to be able to catalyze the reaction of both aromatic and aliphatic aldehydes with high asymmetric inductions. Excellent yields and enantioselectivities have been achieved after optimization. Furthermore, the skeleton of 6-carbon saccharides is synthesized in the reaction of 2-hydoxyacetaldehyde with different protecting groups, which can be derivatized into many saccharide analogs. The mechanism of this reaction is proposed to be concerted based on experiments involving different methods for the reaction quench. A reversal of direction of the asymmetric induction by switching boron to aluminum has been observed. Computational studies show that catalysts derived from boron and aluminum have different geometries at the Lewis acid center.