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Iridium Catalyzed C H Activation Borylation Of Aromatic Heteroaromatic Substrates And Its Application In Small Molecule Synthesis
Download Iridium Catalyzed C H Activation Borylation Of Aromatic Heteroaromatic Substrates And Its Application In Small Molecule Synthesis full books in PDF, epub, and Kindle. Read online Iridium Catalyzed C H Activation Borylation Of Aromatic Heteroaromatic Substrates And Its Application In Small Molecule Synthesis ebook anywhere anytime directly on your device. Fast Download speed and no annoying ads. We cannot guarantee that every ebooks is available!
Book Synopsis Iridium Catalyzed C-H Activation/borylation of Aromatic/heteroaromatic Substrates and Its Application in Small Molecule Synthesis by : Venkata Apparao Kallepalli
Download or read book Iridium Catalyzed C-H Activation/borylation of Aromatic/heteroaromatic Substrates and Its Application in Small Molecule Synthesis written by Venkata Apparao Kallepalli and published by . This book was released on 2010 with total page 157 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Iridium Catalyzed C-H Borylation by : Kristin Anne Gore
Download or read book Iridium Catalyzed C-H Borylation written by Kristin Anne Gore and published by . This book was released on 2017 with total page 290 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Iridium Catalyzed Aromatic Borylation and Its Applications in One-pot Preparations of Substituted Aromatic Building Blocks by : Ghayoor Abbas Chotana
Download or read book Iridium Catalyzed Aromatic Borylation and Its Applications in One-pot Preparations of Substituted Aromatic Building Blocks written by Ghayoor Abbas Chotana and published by . This book was released on 2009 with total page 596 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Synthetic Applications of Iridium-catalyzed Aromatic C-H Borylation by : Feng Shi
Download or read book Synthetic Applications of Iridium-catalyzed Aromatic C-H Borylation written by Feng Shi and published by . This book was released on 2007 with total page 658 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Iridium Catalyzed C-H Borylation by : Behnaz Ghaffari
Download or read book Iridium Catalyzed C-H Borylation written by Behnaz Ghaffari and published by . This book was released on 2016 with total page 212 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Advancing Frontiers in Reactive and Selective Iridium C-h Borylation Catalysis and Targeted Silsesquioxane Synthesis by : Jonathan E. Dannatt
Download or read book Advancing Frontiers in Reactive and Selective Iridium C-h Borylation Catalysis and Targeted Silsesquioxane Synthesis written by Jonathan E. Dannatt and published by . This book was released on 2019 with total page 521 pages. Available in PDF, EPUB and Kindle. Book excerpt: The studies in this dissertation are aimed at uncovering reactive and selective Ir-catalyzed C-H borylation (CHB) catalysts. Due to the high versatility of organoboron species, green methodology to produce the C-B bond is poised to support a myriad of subsequent transformations. These transformations include Suzuki couplings, aminations, oxidations, halogenations, cyanations, and trifluoromethylations.Typical iridium catalyzed CHBs proceed through an iridium trisboryl with a bidentate ligand such as bipyridine or 1,10-phenanthroline. The selectivity of these standard catalysts is generally driven by sterics; however, many methods of overcoming the steric bias have been developed in the two decades since the first thermal catalytic C-H activation borylation. These methods include both inner- and outer-sphere directed mechanisms. Outer-sphere directed borylations have been accomplished by leveraging hydrogen bonding, Lewis acid-base, and ion-pairing as directing elements. In general this reactivity is activated by precise design of the bidentate ligand framework.Herein is reported a subtle electrostatic interaction to direct ortho-borylation of phenols by simply switching boron source from the common B2pin2 (pin = pinacolate) to B2eg2 (eg = ethyleneglycolate). This electrostatic interaction was revealed by a careful computational analysis of key C-H activation transition states. Understanding gained by the computational studies led to the redesign of the boron source which enabled by selectivities of > 99% ortho borylation. This methodology was extended to the highly selective ortho-borylation of anilines, and the underlying mechanism has been interrogated.Currently, iridium based catalysts have been generated to borylate ortho, meta, and even para to a variety of classes of substrates; however, control of selectivity can breakdown in many fluorinated arenes without a directing group. These substrates are challenging because the fluoro moiety being similar in size to a hydrogen offers little in the way of steric bias. While working to overcome these challenges, a serendipitously discovered hydrazone based ligand was discovered. Exploration of the catalysts generated by this ligand revealed not only impressive activity rivaling dtbpy but also incredible selectivity for meta to a fluoro group.In general iridium CHB catalysts selectively activate sp2 C-H bonds leaving all sp3 C-H bonds intact; however, a method to turn on sp3 C-H activation would be desirable. It was reasoned that a directing group able to increase the effective concentration of the iridium catalyst near a C(sp3)-H bond may enable this transformation. Indeed, it was discovered that catalysts able to accept amide directing groups were able to selectively borylate compounds with amide N-methyl substituents.
Book Synopsis Overcoming Regioselectivity Challenges in Iridium Catalyzed C-h Borylation Via Noncovalent Interactions and Advances on Cross Coupling Reactions of Aryl Imidazolylsulfonates by : Jose Raul Montero Bastidas
Download or read book Overcoming Regioselectivity Challenges in Iridium Catalyzed C-h Borylation Via Noncovalent Interactions and Advances on Cross Coupling Reactions of Aryl Imidazolylsulfonates written by Jose Raul Montero Bastidas and published by . This book was released on 2021 with total page 879 pages. Available in PDF, EPUB and Kindle. Book excerpt: Direct functionalization of C0́2H bonds reduces the number of synthetic steps for a target molecule enhancing efficiency and avoiding undesired waste material. Iridium catalyzed C-H activation-borylation (CHB) is an established method to access aryl boronic esters. Regioselectivity challenges can arise when multiple hydrogens are present in the molecule. This thesis describes the design of novel strategies to selective direct the CHB to one specific position.Ortho selective CHB has the challenge to go against the traditional CHB selectivity dictated by steric effects. Previously, our group reported a strategy for highly ortho-selective CHB of anilines by using a small B2eg2 (eg = ethanediol) as the borylating reagent. However, the products were unstable and transesterification with pinacol was needed. Chapter 2 builds upon this issue and presents a solution based on the modulation of the size of the boron partner. Small diboron partners retain the high ortho regioselectivity for CHB of aniline but larger borylating reagents generate more stable products. In our estimation, B2bg2 (bg = 1,2-butanediol) represents the best balance of reactivity, regioselectivity and stability.Remote functionalization including para selective reactions are difficult because a potential directing group would be far from the desired reactive site. Chapter 3 details how para CHB of tetraalkylammonium sulfates and sulfamates have been achieved using bipyridine-ligated Ir boryl catalysts. Selectivities can be modulated by both the length of the alkyl groups in the tetraalkylammonium cations and the substituents on the bipyridine ligands. Ion pairing, where the alkyl groups of the cation shield the meta C8́2H bonds in the counteranions, is proposed to account for para selectivity. The 4,4'-dimethoxy-2,2'-bipyridine ligand gave superior selectivities.The next chapter describes how intramolecular hydrogen bonding (IMHB) can lead to steric shielding effects that can direct CHB regiochemistry. Bpin/arene IMHB can promote remote borylations of N-borylated anilines, 2-amino-N-alkylpyridine, tetrahydroquinolines, indoles and 1-borylated naphthalenes. Our studies support molecular geometries with the Bpin orientation controlled by a C-H0́Ø0́Ø0́ØO IMHB. Calculated rotation barriers to displace the Bpin group are above 4 kcal/mol, suggesting that the planar ground conformation of the borylated arenes is retained during CHB. This study informs researchers to evaluate not only inter- but also intramolecular noncovalent interactions as potential drivers of remote CHB regioselectivity.The borylated products from CHB can be further manipulated in Suzuki-Miyaura cross-coupling (SMC) with aryl halides as the typical electrophilic partner. Aryl imidazolylsulfonates are nongenotoxic electrophiles that can be used in palladium catalyzed SMC to avoid halogenated materials. Chapter 5 shows the efforts towards a nickel-catalyzed SMC of aryl imidazolyl-sulfonates. Results show considerable amounts of the corresponding diarylsulfate formed during the reaction. Interestingly, the diaryl sulfa byproducts were found to be competent electrophilic partners for both palladium and nickel-catalyzed SMC.In summary, this thesis presents novel methodologies to access challenging transformations as the para borylations of phenols, anilines and benzyl alcohols. This was possible by the analysis of the different components of the catalytic system: design of ligands, diboron partners and substrate directing groups and how they interact during the reaction. Finally, the potential of aryl imidazolylsulfonates as nongenotoxic pseudohalides in nickel-catalyzed SMC was evaluated.
Book Synopsis Iridium Complexes in Organic Synthesis by : Luis A. Oro
Download or read book Iridium Complexes in Organic Synthesis written by Luis A. Oro and published by John Wiley & Sons. This book was released on 2008-12-03 with total page 424 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ranging from hydrogenation to hydroamination, cycloadditions and nanoparticles, this first handbook to comprehensively cover the topic of iridium in synthesis discusses the important advances in iridium-catalyzed reactions, namely the use of iridium complexes in enantioselective catalysis. A must for organic, complex and catalytic chemists, as well as those working with/on organometallics.
Book Synopsis Regioselective Iridium Catalyzed C-H Activation/borylation of 2-substituted Indoles by : Sulagna Paul
Download or read book Regioselective Iridium Catalyzed C-H Activation/borylation of 2-substituted Indoles written by Sulagna Paul and published by . This book was released on 2007 with total page 180 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Metal-organic Framework Catalysts for Selective C-H Borylation by : Jesse Brandon Duque
Download or read book Metal-organic Framework Catalysts for Selective C-H Borylation written by Jesse Brandon Duque and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Selective C-H functionalization of organic molecules is one of the most desired transformations in organic synthesis. In recent years, many groups have turned to using supramolecular chemistries to perturb native selectivity in reactions that are predominantly sterically controlled. In instances where there is little steric differentiation, people have turned to the development of supramolecular strategies that involve a level of directionality between substrate and catalyst assemblies primarily through non-covalent interactions. More proximal functionalizations to directing groups on substrates were the first to evolve, however branching out to more distal positions proved to be a formidable challenge. To address this discrepancy, significant research has been devoted to the use of porous materials as a potential support for use in transition metal catalysis to selectively functionalize a wide variety of compounds. One notable material type that has found itself in catalytic applications are metal-organic frameworks (MOFs). Because of their ability to be fitted with different types of metal and organic components, MOFs can contain a variety of functionalities for specific purposes integrated into them. The extended crystalline lattices and rigid framework of MOFs results in fixed spatial relationships between their structural features, and our main interest is exploiting these fixed relationships to selectively functionalize C-H bonds. In the short term, I sought to develop highly selective MOFs as effective C-H borylation catalysts. The long-term goal for my projects is to establish MOFs as tools for small molecule synthesis. The central hypothesis of this work is that the pore environment of MOFs can be modified to control selectivity in otherwise non or poorly selective transformations. To test this hypothesis, I investigated two different modes of perturbing selectivity in borylation reactions: selectivity through confinement and selectivity from substrate docking. In confinement-affected borylation, UiO-67-type MOFs were investigated for size confinement effects that assist in directing substrates into transition states where the ortho borylated regioisomer predominates. In the substrate docking approach, I investigated the use of MOF (Zn) PCN-222 as a metalloporphyrin-based director for substrate docking via Zn-substrate interactions. We were able to observe borylation activity using this MOF catalyst but did not observe significant regioselectivity in our experiments. In parallel with these studies, I developed a new approach toward high throughput experimentation in small molecule MOF catalysis, which allowed us to dispense submilligram quantities of MOF into multiple wells and lead to more efficient workflow using Chembeads technology developed by Abbvie and the team of Noah Tu.
Book Synopsis Iridium-catalyzed Borylation of Aromatic and Aliphatic C-H Bonds: Methodology and Mechanism by :
Download or read book Iridium-catalyzed Borylation of Aromatic and Aliphatic C-H Bonds: Methodology and Mechanism written by and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Directed Iridium C(sp3)-h Borylation Catalysis with High N-adjacent Selectivity by : Anshu Yadav
Download or read book Directed Iridium C(sp3)-h Borylation Catalysis with High N-adjacent Selectivity written by Anshu Yadav and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Modern approaches for the conversion of C-H bonds to C-B bonds involve transition metal catalysts that have various advantages over traditional methods by using cheap and abundant hydrocarbon starting materials, reducing toxic by-products and streamlining the synthesis of biologically important molecules. Metal-catalyzed C-H borylation reactions that produce organoboronic esters are mostly focused on the functionalization of sp2 C-H bonds of heteroarenes and aromatic hydrocarbons. However, in this work the functionalization of sp3 C-H bonds is being explored. Borylation involving sp3 C-H bonds have been shown by Sawamura and co-workers with solid silica supported phosphine ligands offering a directing strategy where a metal center can accept donor directing groups. While this ligand generates highly active borylation catalysts, it requires a lot of steps in the synthesis of the ligand. In this work, easily synthesized homogeneous bidentate monoanionic ligands were tested for the borylation of sp3 C-H bonds. Herein is reported borylation of sp3 C-H bonds of N-methyl amide groups using [Ir(OMe)(cod)]2 as a precatalyst and B2pin2 as a commercially available boron source. Following the borylation of amide as a directing group, amidine molecules are being investigated.
Book Synopsis Frontiers in Iridium-Catalyzed C-H Borylation by : Matthew Alan Larsen
Download or read book Frontiers in Iridium-Catalyzed C-H Borylation written by Matthew Alan Larsen and published by . This book was released on 2016 with total page 246 pages. Available in PDF, EPUB and Kindle. Book excerpt: The following dissertation discusses the development of novel methodology for the catalytic borylation of C-H bonds and includes in-depth studies on the mechanism and selectivity of these synthetic transformations. These methods include the borylation of heteroaryl C-H bonds, the selective borylation of benzylic C-H bonds, and the directed and undirected borylation of unactivated alkyl C-H bonds. Chapter 1 contains a comprehensive review of C-H borylation methodology. This review focuses on the initial development of catalytic C-H borylation and on the state-of- the-art of methodology for the undirected and directed borylation of aryl, benzylic, and alkyl C-H bonds. Additionally, this review highlights knowledge gaps and unsolved challenges. Furthermore, this review provides the author's opinion on future directions for research on the borylation of C-H bonds. Chapter 2 describes the study of the iridium-catalyzed borylation of heteroaryl C- H bonds. Contained is an examination of the scope of the borylation of heterocycles containing more than one heteroatom and rules for predicting the site-selectivity of this reaction. Also included are experimental and computational studies that reveal the mechanism of this reaction and the origins of the observed regioselectivity. Chapter 3 discusses the development of the selective borylation of the primary benzylic C-H bonds of methylarenes. Key to this development was the discovery that the combination of a novel iridium catalyst and a silylborane allows for the selective borylation of benzylic C-H bonds over aryl C-H bonds. Experimental and computational studies that investigate the origins of this selectivity are also discussed. Chapter 4 discusses the development of the iridium-catalyzed, hydrosilyl-directed borylation of alkyl C-H bonds. This methodology allows for the diastereoselective borylation of secondary alkyl C-H bonds under relatively mild conditions. Chapter 5 explores the effect of ligand structure on the rates of alkyl C-H borylation catalyzed by Ir-phenanthroline complexes. Experimental and computational studies reveal that in addition to the relative electron-donating ability of phenanthrolines, weak interactions involving the phenanthroline in the transition state of the turnover- limiting step for the borylation of alkyl C-H bonds can have a large impact on the relative rates of alkyl C-H borylation catalyzed by various Ir-phenanthroline complexes.
Book Synopsis Green Chemistry and Catalysis by : R. A. Sheldon
Download or read book Green Chemistry and Catalysis written by R. A. Sheldon and published by John Wiley & Sons. This book was released on 2007-06-27 with total page 448 pages. Available in PDF, EPUB and Kindle. Book excerpt: This first book to focus on catalytic processes from the viewpoint of green chemistry presents every important aspect: · Numerous catalytic reductions and oxidations methods · Solid-acid and solid-base catalysis · C-C bond formation reactions · Biocatalysis · Asymmetric catalysis · Novel reaction media like e.g. ionic liquids, supercritical CO2 · Renewable raw materials Written by Roger A. Sheldon -- without doubt one of the leaders in the field with much experience in academia and industry -- and his co-workers, the result is a unified whole, an indispensable source for every scientist looking to improve catalytic reactions, whether in the college or company lab.
Book Synopsis Organotransition Metal Chemistry: From Bonding to Catalysis by : John F. Hartwig
Download or read book Organotransition Metal Chemistry: From Bonding to Catalysis written by John F. Hartwig and published by . This book was released on 2010-02-10 with total page 1172 pages. Available in PDF, EPUB and Kindle. Book excerpt: Based on Collman et al.'s best-selling classic book, Principles and Applications of Organotransition Metal Chemistry, Hartwig's text consists of new or thoroughly updated and restructured chapters and provides an in-depth view into mechanism, reaction scope, and applications. It covers the most important developments in the field over the last twenty years with great clarity with a selective, but thorough and authoritative coverage of the fundamentals of organometallic chemistry, the elementary reactions of these complexes, and many catalytic processes occurring through organometallic intermediates, making this the Organotransition Metal Chemistry text for a new generation of scientists.
Book Synopsis Artificial Metalloenzymes and MetalloDNAzymes in Catalysis by : Montserrat Diéguez
Download or read book Artificial Metalloenzymes and MetalloDNAzymes in Catalysis written by Montserrat Diéguez and published by John Wiley & Sons. This book was released on 2018-02-21 with total page 431 pages. Available in PDF, EPUB and Kindle. Book excerpt: An important reference for researchers in the field of metal-enzyme hybrid catalysis Artificial Metalloenzymes and MetalloDNAzymes in Catalysis offers a comprehensive review of the most current strategies, developed over recent decades, for the design, synthesis, and optimization of these hybrid catalysts as well as material about their application. The contributors—noted experts in the field—present information on the preparation, characterization, and optimization of artificial metalloenzymes in a timely and authoritative manner. The authors present a thorough examination of this interesting new platform for catalysis that combines the excellent selective recognition/binding properties of enzymes with transition metal catalysts. The text includes information on the various applications of metal-enzyme hybrid catalysts for novel reactions, offers insights into the latest advances in the field, and contains an informative perspective on the future: Explores the development of artificial metalloenzymes, the modern and strongly evolving research field on the verge of industrial application Contains a comprehensive reference to the research area of metal-enzyme hybrid catalysis that has experienced tremendous growth in recent years Includes contributions from leading researchers in the field Shows how this new catalysis combines the selective recognition/binding properties of enzymes with transition metal catalysts Written for catalytic chemists, bioinorganic chemists, biochemists, and organic chemists, Artificial Metalloenzymes and MetalloDNAzymes in Catalysis offers a unique reference to the fundamentals, concepts, applications, and the most recent developments for more efficient and sustainable synthesis.
Book Synopsis C-H Activation for Asymmetric Synthesis by : Françoise Colobert
Download or read book C-H Activation for Asymmetric Synthesis written by Françoise Colobert and published by John Wiley & Sons. This book was released on 2019-11-11 with total page 294 pages. Available in PDF, EPUB and Kindle. Book excerpt: Provides, in one handbook, comprehensive coverage of one of the hottest topics in stereoselective chemistry Written by leading international authors in the field, this book introduces readers to C-H activation in asymmetric synthesis along with all of its facets. It presents stereoselective C-H functionalization with a broad coverage, from outer-sphere to inner-sphere C-H bond activation, and from the control of olefin geometry to the induction of point, planar and axial chirality. Moreover, methods wherein asymmetry is introduced either during the C-H activation or in a different elementary step are discussed. Presented in two parts?asymmetric activation of C(sp3)-H bonds and stereoselective synthesis implying activation of C(sp2)-H bonds?CH-Activation for Asymmetric Synthesis showcases the diversity of stereogenic elements, which can now be constructed by C-H activation methods. Chapters in Part 1 cover: C(sp3)-H bond insertion by metal carbenoids and nitrenoids; stereoselective C-C bond and C-N bond forming reactions through C(sp3)?H bond insertion of metal nitrenoids; enantioselective intra- and intermolecular couplings; and more. Part 2 looks at: C-H activation involved in stereodiscriminant step; planar chirality; diastereoselective formation of alkenes through C(sp2)?H bond activation; amongst other methods. -Covers one of the most rapidly developing fields in organic synthesis and catalysis -Clearly structured in two parts (activation of sp3- and activation of sp2-H bonds) -Edited by two leading experts in C-H activation in asymmetric synthesis CH-Activation for Asymmetric Synthesis will be of high interest to chemists in academia, as well as those in the pharmaceutical and agrochemical industry.
