anion-binding-catalysis

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Anion Binding Catalysis

Author : Olga Garcia-Mancheno
ISBN : 9783527348572
Genre : Technology & Engineering
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Explores the potential of new types of anion-binding catalysts to solve challenging synthetic problems Anion-Binding Catalysis introduces readers to the use of anion-binding processes in catalytic chemical activation, exploring how this approach can contribute to the future design of novel synthetic transformations. Featuring contributions by world-renowned scientists in the field, this authoritative volume describes the structure, properties, and catalytic applications of anions as well as synthetic applications and practical analytical methods. In-depth chapters are organized by type of catalyst rather than reaction type, providing readers with an accessible overview of the existing classes of effective catalysts. The authors discuss the use of halogens as counteranions, the combination of (thio)urea and squaramide-based anion-binding with other types of organocatalysis, anion-binding catalysis by pnictogen and tetrel bonding, nucleophilic co-catalysis, anion-binding catalysis by pnictogen and tetrel bonding, and more. Helping readers appreciate and evaluate the potential of anion-binding catalysis, this timely book: Illustrates the historical development, activation mode, and importance of anion-binding in chemical catalysis Explains the analytic methods used to determine the anion-binding affinity of the catalysts Describes catalytic and synthetic applications of common NH- and OH-based hydrogen-donor catalysts as well as C-H triazole/triazolium catalysts Covers amino-catalysis involving enamine, dienamine, or iminium activation approaches Discusses new trends in the field of anion-binding catalysis, such as the combination of anion-binding with other types of catalysis Presenting the current state of the field as well as the synthetic potential of anion-binding catalysis in future, Anion-Binding Catalysis is essential reading for researchers in both academia and industry involved in organic synthesis, homogeneous catalysis, and pharmaceutical chemistry.

Anion Binding Catalysis With Molecular Knots And Machines

Author : Javier Jaramillo Garca
ISBN : OCLC:1112367083
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New Entries To Asymmetric Anion Binding Catalysis With Chiral Oligotriazoles

Author : Kirandeep Kaur
ISBN : OCLC:1294509215
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Development Of Anion Binding Approaches To Asymmetric Catalysis

Author : Nisha Mittal
ISBN : OCLC:889312962
Genre : Asymmetry (Chemistry)
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The dual catalytic approach in asymmetric catalysis has gained considerable attention in recent times. Many otherwise inefficient and unattainable chemical processes can be accomplished by this approach. Outlined within this dissertation are recent efforts in improving the overall efficiency of this process as well as expanding this method involving nucleophilic/anion-binding catalysis to the kinetic resolution of allylic amines and 1,2-diamines. An efficient catalytic system has been identified through targeted structural modifications of both the achiral nucleophilic catalyst and the chiral anion-binding co-catalyst. This has resulted in increased selectivities while simultaneously allowing for significantly reduced catalyst loadings. Based on the mechanistic insight into the anion binding approach for the kinetic resolution of amines, we established that there was a 1:1 catalyst to benzoate anion binding ratio. Cooperative approaches in which Brønsted acids act in concert with other Brønsted acids or (thio) urea co-catalysts have gained significance. This study describes the synthesis of a new class of chiral conjugate-base-stabilized Brønsted acid catalysts and a new concept for cooperative hydrogen bonding/ Brønsted acid catalysis. These chiral Brønsted acids contain a carboxylic acid group which is connected via an appropriate linker to an anion receptor moiety such as a thiourea. Substrate protonation by the catalyst results in the association of the conjugate base with the anion recognition site, resulting in the formation of a rigid catalyst/substrate ion pair. We were able to successfully apply this concept to the catalytic enantioselective Povarov and Pictet-Spengler reactions.

Chiral Triazoles In Anion Binding Catalysis New Enantioselective Applications Binding Studies And Mechanistic Insights

Author : Julia Bamberger
ISBN : OCLC:1190164947
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Enantioselective Nucleophilic Dearomatization Of Heteroarenes By Anion Binding Catalysis

Author : Theresa Fischer
ISBN : OCLC:1137011896
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Metal Salen Complexes In Anion Binding And Catalysis

Author : Eric R. Libra
ISBN : OCLC:662508896
Genre :
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ABSTRACT: Most forms of life require the recognition and transportation of anions. There have been numerous efforts to develop synthetic receptor systems that are both efficient and selective for the coordination of anions. Nature often employs the use of OH groups for anion coordination, yet this binding mode is one that has not been explored in the area of synthetic anion receptor design. A series of substituted metal salen compounds have been developed that show a high affinity for the coordination of anions. The rigid metal salen macrocycle can orientate four phenol groups into a tetrahedral array that tightly and selectively binds fluoride through four strong OH-F hydrogen bonding interactions. The size of the anion binding cavity can be regulated by the incorporation of different metal centers, enabling the properties of the system to be modified. Metals also offer convenient pathways to report the binding event via spectral changes from the strong metal to ligand charge transfer transitions, making these receptors anion sensors. Not only can the metal salen system organize groups for anion binding, they can also be used as chiral catalysts. The synthesis of a rigid and sterically bulky metal salen complex has been undertaken for the use as an asymmetric catalyst to promote organic transformations.

Supramolecular Catalysis

Author : Piet W.N.M. van Leeuwen
ISBN : 9783527349029
Genre : Technology & Engineering
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Supramolecular Catalysis Provides a timely and detailed overview of the expanding field of supramolecular catalysis The subdiscpline of supramolecular catalysis has expanded in recent years, benefiting from the development of homogeneous catalysis and supramolecular chemistry. Supramolecular catalysis allows chemists to design custom-tailored metal and organic catalysts by devising non-covalent interactions between the various components of the reaction. Edited by two world-renowned researchers, Supramolecular Catalysis: New Directions and Developments summarizes the most significant developments in the dynamic, interdisciplinary field. Contributions from an international panel of more than forty experts address a broad range of topics covering both organic and metal catalysts, including emergent catalysis by self-replicating molecules, switchable catalysis using allosteric effects, supramolecular helical catalysts, and transition metal catalysis in confined spaces. This authoritative and up-to-date volume: Covers ligand-ligand interactions, assembled multi-component catalysts, ligand-substrate interactions, and supramolecular organocatalysis and non-classical interactions Presents recent work on supramolecular catalysis in water, supramolecular allosteric catalysis, and catalysis promoted by discrete cages, capsules, and other confined environments Highlights current research trends and discusses the future of supramolecular catalysis Includes full references and numerous figures, tables, and color illustrations Supramolecular Catalysis: New Directions and Developments is essential reading for catalytic chemists, complex chemists, biochemists, polymer chemists, spectroscopists, and chemists working with organometallics.

Design Of Novel Chiral Tri And Tetratriazole H Donor Catalysts And Their Application In Enantioselective Dearomatization Reactions By Anion Binding Catalysis

Author : Qui-Nhi Duong
ISBN : OCLC:1313917470
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Anion Binding And Catalytic Studies Of Metal Salen Complexes

Author : Candace A. Zieleniuk
ISBN : OCLC:489208747
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ABSTRACT: Of all the substrates and cofactors involved in biological processes, it is estimated that 70-75% of the species are negatively charged. Since anionic species are essential for life, their presence or imperfect regulation can be either beneficial or harmful to living organisms. Despite the importance of anions in nature, the recognition of anions by synthetic hosts has been largely unexplored. A series of tripodal triphenoxymethane salens were synthesized and then used to chelate lanthanides and transition metals with 3oxidation states. The metal chelation facilitates the formation of well-defined binding pockets containing six O-H moieties of varying sizes depending upon the chelated metal ion. The same approach was also used to produce large macrocyclic urea-based salen ligands and the corresponding metal complexes as well as mixed O-H/N-H metal salens. Both the O-H and N-H based complexes were treated with the tetrabutylammonium salts of a wide range of anion and then studied for their anion binding capabilities. Chiral metal salen molecules have also been used extensively to perform asymmetric catalysis. A series of chiral BINAM triphenoxymethane based salen ligands were produced and used to synthesize extremely bulky chiral dinuclear catalysts. These catalysts were found to facilitate the asymmetric addition of ZnEt2 to benzaldehyde giving a secondary alcohol. In addition, the chiral BINAM catalysts can also produce quantitative amounts of cyclic carbonates through a cycloaddition reaction of CO2 to epoxides. The synthesis of the metal salen complexes and the results of the anion binding and catalytic studies are presented herein.

Activation Of Weak Nucleophiles In Anion Binding Catalysis

Author : Yongho Park
ISBN : OCLC:1004374737
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In Chapter 1, a diastereoselective glycosylation reaction of glycosyl halides is reported. The transformation is catalyzed by macrocyclic bis-thiourea catalysts to afford [beta]-glycosides. Experimental and computational evidence indicate a stereospecific, invertive mechanism in which thiourea moieties facilitate leaving group departure and the amide carbonyl group of the catalyst activates alcohol nucleophiles via general base catalysis.

Designed Molecular Space In Material Science And Catalysis

Author : Seiji Shirakawa
ISBN : 9789811312564
Genre : Science
File Size : 57. 91 MB
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This book focuses on molecular space chemistry, which is recognized as an important concept for the design of novel functional materials and catalysts. A wide variety of topics and ideas included in this book are based on that concept. The book showcases recent representative examples of molecular space design to create functional materials and catalysts possessing unique properties. This unique volume will be of great interest to chemists in a wide variety of research fields, including organic, inorganic, biological, polymer, and supramolecular chemistry. Readers will obtain new ideas and directions to create novel functional molecules, and those ideas will lead to innovative views of science.

Engaging Chiral Cationic Intermediates By Anion Binding In Asymmetric Catalysis

Author : Hu Zhang
ISBN : OCLC:948345784
Genre :
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In Chapters 1, we provide an overview of the progress and challenges in the development of enantioselective halo- and seleno-functionalization reactions, which proceed via three-membered ring cationic halonium or seleniranium ions.

Catalytic Asymmetric Synthesis

Author : Takahiko Akiyama
ISBN : 9781119736417
Genre : Science
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Seminal text presenting detailed accounts of the most important catalytic asymmetric reactions known today This book covers the preparation of enantiomerically pure or enriched chemical compounds by use of chiral catalyst molecules. While reviewing the most important catalytic methods for asymmetric organic synthesis, this book highlights the most important and recent developments in catalytic asymmetric synthesis. Edited by two well-qualified experts, sample topics covered in the work include: Metal catalysis, organocatalysis, photoredox catalysis, enzyme catalysis C-H bond functionalization reactions Carbon-carbon bond formation reactions, carbon-halogen bond formation reactions, hydrogenations, polymerizations, flow reactions Axially chiral compounds Retaining the best of its predecessors but now thoroughly up to date with the important and recent developments in catalytic asymmetric synthesis, the 4th edition of Catalytic Asymmetric Synthesis serves as an excellent desktop reference and text for researchers and students, from upper-level undergraduates all the way to experienced professionals in industry or academia.

Catalytic Cascade Reactions

Author : Peng-Fei Xu
ISBN : 9781118356630
Genre : Science
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Demonstrates the advantages of catalytic cascade reactionsfor synthesizing natural products and pharmaceuticals Riding the wave of green chemistry, catalytic cascade reactionshave become one of the most active research areas in organicsynthesis. During a cascade reaction, just one reaction solvent,one workup procedure, and one purification step are needed, thussignificantly increasing synthetic efficiency. Featuring contributions from an international team of pioneersin the field, Catalytic Cascade Reactions demonstrates theversatility and application of these reactions for synthesizingvaluable compounds. The book examines both organocatalysis andtransition-metal catalysis reactions, bringing readers up to datewith the latest discoveries and activities in all major areas ofcatalytic cascade reaction research. Catalytic Cascade Reactions begins with three chaptersdedicated to organocatalytic cascade reactions, exploring amines,Brønsted acids, and the application of organocatalytic cascadereactions in natural product synthesis and drug discovery. Next,the book covers: Gold-catalyzed cascade reactions Cascade reactions catalyzed by ruthenium, iron, iridium,rhodium, and copper Palladium-catalyzed cascade reactions of alkenes, alkynes, andallenes Application of transition-metal catalyzed cascade reactions innatural product synthesis and drug discovery Engineering mono- and multifunctional nanocatalysts for cascadereactions Multiple-catalyst-promoted cascade reactions All chapters are thoroughly referenced, providing quick accessto important original research findings and reviews so that readerscan explore individual topics in greater depth. Drawing together and analyzing published findings scatteredacross the literature, this book provides a single source thatencapsulates our current understanding of catalytic cascadeprocesses. Moreover, it sets the stage for the development of newcatalytic cascade reactions and their applications.

I Enantioselective Acylation Of Silyl Ketene Acetals Through Fluoride Anion Binding Catalysis Ii Development Of A Practical Method For The Synthesis Of Highly Enantioenriched Trans 1 2 Amino Alcohols

Author : James Andrew Birrell
ISBN : OCLC:864908434
Genre :
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A highly enantioselective acylation of silyl ketene acetals with acyl fluorides was developed to generate useful alpha,alpha-disubstituted butyrolactone products in high yield and excellent enantioselectivities. This transformation is promoted by an arylpyrrolidino thiourea catalyst and 4-pyrrolidinopyridine and represents the first example of enantioselective thiourea anion-binding catalysis with fluoride. Mechanistic investigations revealed both catalysts to be necessary for reaction to occur, suggesting the thiourea aids in the generation of the key N-acylpyridinium/fluoride ion pair. The outstanding hydrogen-bond-accepting ability of fluoride is likely important in this regard. In addition, a strong dependence on both the N-acylpyridinium counteranion and the substituents on the silicon group of the silyl ketene acetal were observed, highlighting the importance of the silicon-fluoride interaction.

Macrocyclic Polycation Complexes For Secondary Anion Binding Molecular Recognition And Catalysis

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ISBN : OCLC:227856574
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The research described in eighteen technical reports are summarized in this final report. The work accomplished involves the application of macrocyclic ligands to the recognition of small molecules and anions, and the use of the metal complexes of these macrocyclic ligands for molecular recognition and catalysis of reactions of the guest molecules and anions. The reaction types investigated include oxygen carriers, dinuclear copper(l) dioxygen complexes as catalytic intermediates in the oxidation of various substrates by molecular oxygen, the recognition and reactivity of small molecules and anions as guests with hosts consisting of protonated polyaza macrocyclic ligands and their mononuclear and dinuclear metal complexes, and the oxidation of coordinated substrates in dinuclear cobalt macrocyclic complexes containing coordinated dioxygen.

Aromatic Interactions

Author : Darren W. Johnson
ISBN : 9781782624172
Genre : Science
File Size : 54. 32 MB
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The field of aromatic interactions, the fundamental nature of substituent effects and the identification of contacts between anions and aromatic systems have generated stimulating arguments in recent years. New theoretical frameworks have been developed and tested and aromatic interactions have emerged as potential solutions for varied problems in biology and materials science. This book provides a wide ranging survey of the latest findings and advances surrounding aromatic interactions, stretching from the fundamentals to modern applications in synthesis, biology and materials chemistry. It also discusses computational, experimental and analytical approaches to understanding these interactions, including pi-pi, anion-pi, and cation-pi interactions. Aromatic Interactions: Frontiers in Knowledge and Application is a useful text for advanced students and researchers, and appeals to those working within the fields of supramolecular chemistry, computational chemistry and thermodynamics.

Multicatalyst System In Asymmetric Catalysis

Author : Jian Zhou
ISBN : 9781118071861
Genre : Science
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Synthetic Approaches To Nonaromatic Nitrogen Heterocycles

Author : Ana Maria Faisca Phillips
ISBN : 9781119708759
Genre : Science
File Size : 75. 90 MB
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A comprehensive overview of synthetic strategies for nonaromatic nitrogen heterocycles Nitrogen heterocycles are extremely widely distributed in nature, as well as in synthetic substances found in pharmaceuticals, agrochemicals, and materials chemistry. With new structures and medicines that include these structures emerging yearly, and a vast new journal literature to describe them, anyone who wants to be effective in R&D needs to easily access a synthesis of the latest research. This state-of-the-art survey explores recent developments in the most widely used reactions, as well as completely new ones. Highlights the major modern synthetic methods known to obtain nonaromatic nitrogen heterocycles, and their practical applications Topics include enantioselective synthesis and catalysis, photocatalysis, biocatalysis, microwave-assisted synthesis, reactions of oximes and nitrones, and ionic liquids Discusses how to synthesize rings of specific sizes Covers sustainable synthetic approaches for obtaining salts Whether you are using nonaromatic nitrogen compounds as an academic researcher, a synthetic chemist in industry, or an advanced student, this book is an essential, up-to-date resource to support your work.

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