Strategies for Enantioselective Carbon-Heteroatom Bond Formation PDF Download
Are you looking for read ebook online? Search for your book and save it on your Kindle device, PC, phones or tablets. Download Strategies for Enantioselective Carbon-Heteroatom Bond Formation PDF full book. Access full book title Strategies for Enantioselective Carbon-Heteroatom Bond Formation by Dillon Harding Miles. Download full books in PDF and EPUB format.
Author: Dillon Harding Miles
Publisher:
ISBN:
Category :
Languages : en
Pages : 225
Get Book Here
Book Description
Although the topics discussed in this dissertation each stand as unique areas of research in their respective fields, they are united under the common approach of using catalyst structure to control the selectivity of a particular reaction. For the majority of these transformations, use of a chiral counterion-based catalyst, a relatively new strategy in the field of asymmetric synthesis, proved essential for successful enantioinduction. An additional subtheme, design and application of electrophilic reaction components, provided an added dimension of control to the reaction outcome. Chapter 1 presents a brief perspective on the gold-catalyzed synthesis of heterocycles with an emphasis on previously published hydrofunctionalizations of allene substrates containing tethered nucleophiles, thus providing context for Chapter 2. Chapter 2 describes efforts toward the gold(I)-catalyzed enantioselective bromocyclization of allenes. The primary goal of this project was the synthesis of enantioenriched vinyl halide-containing products containing enantioenriched allylic stereocenters within a heterocyclic ring moiety. Efforts to synthesize these molecules were initially hindered if more traditional electrophilic halogen sources such as N-bromosuccinimide were used; however, employment of the relatively unexplored N-bromolactams resulted in high yields and selectivities of the desired products. Additionally, this methodology partially utilized chiral phosphate-based molecules as counterions as an additional source of chiral information. Chapter 3 takes inspiration from the previous use of chiral phosphate counterions to accomplish an enantioselective intermolecular [alpha]-amination reaction utilizing nucleophilic nitrogen sources. This project sought a reaction complementary to previously existing versions which utilized electrophilic sources of nitrogen. Choice of chiral phosphoric acid in addition to an appropriately activated azoalkene substrate was critical for the high levels of yield and enantioselectivity observed. While expanding the substrate scope, a serendipitous kinetic resolution was observed, which revealed an interesting mode of reactivity associated with [alpha]-arylamino hydrazones. Chapter 4, the final installment, is intended to be an initial survey of explorations into Pummerer-like reactivity again utilizing chiral phosphoric acids or phosphates as a source of chirality. Still in its infancy, this project has explored various carbon-heteroatom bond-forming reactions utilizing either sulfoxide or fluorosulfonium moieties as a source of oxidized sulfur to enable an enantioselective cross-dehydrogenative coupling using a Pummerer-like reaction mechanism. One eventual goal would be to expand the space of enantioenriched sulfur-containing heterocycles.
Author: Dillon Harding Miles
Publisher:
ISBN:
Category :
Languages : en
Pages : 225
Get Book Here
Book Description
Although the topics discussed in this dissertation each stand as unique areas of research in their respective fields, they are united under the common approach of using catalyst structure to control the selectivity of a particular reaction. For the majority of these transformations, use of a chiral counterion-based catalyst, a relatively new strategy in the field of asymmetric synthesis, proved essential for successful enantioinduction. An additional subtheme, design and application of electrophilic reaction components, provided an added dimension of control to the reaction outcome. Chapter 1 presents a brief perspective on the gold-catalyzed synthesis of heterocycles with an emphasis on previously published hydrofunctionalizations of allene substrates containing tethered nucleophiles, thus providing context for Chapter 2. Chapter 2 describes efforts toward the gold(I)-catalyzed enantioselective bromocyclization of allenes. The primary goal of this project was the synthesis of enantioenriched vinyl halide-containing products containing enantioenriched allylic stereocenters within a heterocyclic ring moiety. Efforts to synthesize these molecules were initially hindered if more traditional electrophilic halogen sources such as N-bromosuccinimide were used; however, employment of the relatively unexplored N-bromolactams resulted in high yields and selectivities of the desired products. Additionally, this methodology partially utilized chiral phosphate-based molecules as counterions as an additional source of chiral information. Chapter 3 takes inspiration from the previous use of chiral phosphate counterions to accomplish an enantioselective intermolecular [alpha]-amination reaction utilizing nucleophilic nitrogen sources. This project sought a reaction complementary to previously existing versions which utilized electrophilic sources of nitrogen. Choice of chiral phosphoric acid in addition to an appropriately activated azoalkene substrate was critical for the high levels of yield and enantioselectivity observed. While expanding the substrate scope, a serendipitous kinetic resolution was observed, which revealed an interesting mode of reactivity associated with [alpha]-arylamino hydrazones. Chapter 4, the final installment, is intended to be an initial survey of explorations into Pummerer-like reactivity again utilizing chiral phosphoric acids or phosphates as a source of chirality. Still in its infancy, this project has explored various carbon-heteroatom bond-forming reactions utilizing either sulfoxide or fluorosulfonium moieties as a source of oxidized sulfur to enable an enantioselective cross-dehydrogenative coupling using a Pummerer-like reaction mechanism. One eventual goal would be to expand the space of enantioenriched sulfur-containing heterocycles.
Author: Andrei K. Yudin
Publisher: John Wiley & Sons
ISBN: 3527633405
Category : Science
Languages : en
Pages : 541
Get Book Here
Book Description
Written by an experienced editor widely acclaimed within the scientific community, this book covers everything fromo9xygen to nitrogen functionalities. From the contents: Palladium-Catalyzed Syntheses of Five-Member Saturated Heterocyclic and of Aromatic Heterodynes Palladium-Catalysis for Oxidative 1, 2-Difunctionalization of Alkenes Rhodium-Catalyzed Amination of C-H-Bonds Carbon-Heteroatom Bond Formation by RH(I)-Catalyzed Ring-Opening Reactions Transition Metal-Catalyzed Synthesis of Lactones and of Monocyclic and Fused Five-Membered Aromatic heterocycles the Formation of Carbon-Sulfur and Carbon-Selenium bonds by Substitution and Addition reactions catalyzed by Transition Metal Complexes New Reactions of Copper Acetylides Gold Catalyzed Addition of Nitrogen, Sulfur and Oxygen Nucleophiles to C-C Multiple Bonds. The result is an indispensable source of information for the Strategic Planning of the Synthetic routes for organic, catalytic and medicinal chemists, as well as chemists in industry.
Author: Rainer Mahrwald
Publisher: Springer Science & Business Media
ISBN: 9048138671
Category : Science
Languages : en
Pages : 400
Get Book Here
Book Description
Organocatalyzed Reactions I and II presents a timely summary of organocatalysed reactions including: a) Enantioselective C-C bond formation processes e.g. Michael-addition, Mannich-reaction, Hydrocyanation (Strecker-reaction), aldol reaction, allylation, cycloadditions, aza-Diels-Alder reactions, benzoin condensation, Stetter reaction, conjugative Umpolung, asymmetric Friedel-Crafts reactions; b) Asymmetric enantioselective reduction processes e.g. Reductive amination of aldehydes or ketones, asymmetric transfer hydrogenation; c) Asymmetric enantioselective oxidation processes; d) Asymmetric epoxidation, Bayer-Villiger oxidation; e) Enantioselective a-functionalization; f) A-alkylation of ketones, a-halogenation and a-oxidation of carbonyl compounds.
Author:
Publisher: Elsevier
ISBN: 044323700X
Category : Science
Languages : en
Pages : 338
Get Book Here
Book Description
Enantioselective C-C Bond Forming Reactions: From Metal Complex-, Organo-, and Bio-catalyzed Perspectives, Volume 73 in the Advances in Catalysis series, highlights new advances in the field, with this new volume presenting interesting chapters on topics such as An introduction to Chirality, Metal-catalyzed stereoselective C-C-bond forming reactions, Enantioselective C-C bond forming reactions promoted by organocatalysts based on unnatural amino acid derivatives, Enantioselective C-C bond formation in complex multicatalytic system, Gold-based multicatalytic systems for enantioselective C-C Bond forming reactions, Novel enzymatic tools for C-C bond formation through the development of new-to-nature biocatalysis, and more. - Provides the authority and expertise of leading contributors from an international board of authors - Presents the latest release in Advances in Catalysis serials - Updated release includes the latest information in the field
Author: Françoise Colobert
Publisher: John Wiley & Sons
ISBN: 3527343407
Category : Science
Languages : en
Pages : 294
Get Book Here
Book Description
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.
Author: Joseph Benjamin Parry
Publisher:
ISBN:
Category :
Languages : en
Pages : 0
Get Book Here
Book Description
Electrochemical alkene diazidation offers an attractive strategy towards vicinal diamines due to the mild reaction conditions offered by oxidative electrochemistry and facile azide N3 to NH2 reduction methodologies. The electrochemical oxidation of TEMPO in the presence of N3- and an alkene was shown to electrochemically form azidooxygenated products alongside minor amounts of diazide. Diazide product formation was amplified alongside azidooxygenation suppression through the synthesis of a sterically congested catalyst CHAMPO. CHAMPO was able to successfully catalyze the formation of diazides across a variety of alkene types and substrates featuring oxidatively sensitive functional groups. Organometallic catalysts offer an alternative route to carbon heteroatom bond formation as unlike purely organic catalysts, the multiple oxidation states accessible through redox manipulation of a metal center allows access to otherwise inaccessible reaction paradigms. Carbazole-based PNP pincer complexes of Co were synthesized and reacted with RN3 to furnish Co-imidos (Co=NR) which have been invoked as key intermediates in C-H amination and C=C aziridination. Upon full characterization, the competency of Co=NR towards C-N bond formation was investigated. A second generation PNP pincer complex was synthesized to incorporate binding of a main-group metal with the hypothesis that transition metal main-group cooperativity would allow for activation and binding of ligands atypical for monometallic systems. Heterobimetallic systems of E-TM (E = Gallium and Indium, M = Cobalt and Nickel) were synthesized and characterized using SXRD and their activity towards Nitrogen oxyanion (NO3- and (NO2-) binding was investigated.
Author: Vasyl Andrushko
Publisher: John Wiley & Sons
ISBN: 1118628330
Category : Science
Languages : en
Pages : 1836
Get Book Here
Book Description
Brings together the best tested and proven stereoselective synthetic methods Both the chemical and pharmaceutical industries are increasingly dependent on stereoselective synthetic methods and strategies for the generation of new chiral drugs and natural products that offer specific 3-D structures. With the publication of Stereoselective Synthesis of Drugs and Natural Products, researchers can turn to this comprehensive two-volume work to guide them through all the core methods for the synthesis of chiral drugs and natural products. Stereoselective Synthesis of Drugs and Natural Products features contributions from an international team of synthetic chemists and pharmaceutical and natural product researchers. These authors have reviewed the tremendous body of literature in the field in order to compile a set of reliable, tested, and proven methods alongside step-by-step guidance. This practical resource not only explores synthetic methodology, but also reaction mechanisms and applications in medicinal chemistry and drug discovery. The publication begins with an introductory chapter covering general principles and methodologies, nomenclature, and strategies of stereoselective synthesis. Next, it is divided into three parts: Part One: General Methods and Strategies Part Two: Stereoselective Synthesis by Bond Formation including C-C bond formation C-H bond formation C-O bond formation C-N bond formation Other C-heteroatom formation and other bond formation Part Three: Methods of Analysis and Chiral Separation References in every chapter serve as a gateway to the literature in the field. With this publication as their guide, chemists involved in the stereoselective synthesis of drugs and natural products now have a single, expertly edited source for all the methods they need.
Author: Ken Tanaka
Publisher: John Wiley & Sons
ISBN: 111862999X
Category : Science
Languages : en
Pages : 785
Get Book Here
Book Description
State-of-the-science methods, synthetic routes, and strategies to construct aromatic rings The development of new reactions for the synthesis of aromatic compounds is a highly active research area in organic synthesis, providing new functional organic materials, functional reagents, and biologically active compounds. Recently, significant advances in transition-metal-mediated reactions have enabled the efficient and practical construction of new aromatic rings with useful properties and applications. This book draws together and reviews all the latest discoveries and methods in transition-metal-mediated reactions, offering readers promising new routes to design and construct complex aromatic compounds. Integrating metal catalysis with aromatic compound synthesis, Transition-Metal-Mediated Aromatic Ring Construction offers a practical guide to the methods, synthetic routes, and strategies for constructing aromatic compounds. The book's five parts examine: [2+2+2], [2+2+1], and related cycloaddition reactions [4+2], [3+2], and related cycloaddition reactions Electrocyclization reactions Coupling and addition reactions Other important transformations, including methathesis reactions and skeletal rearrangement reactions Edited by Ken Tanaka, an internationally recognized expert in the field of transition-metal catalysis, the book features authors who are leading pioneers and researchers in synthetic reactions. Their contributions reflect a thorough review and analysis of the literature as well as their own firsthand laboratory experience developing new aromatic compounds. All chapters end with a summary and outlook, setting forth new avenues of research and forecasting new discoveries. There are also references at the end of each chapter, guiding readers to important original research reports and reviews. In summary, Transition-Metal-Mediated Aromatic Ring Construction offers synthetic chemists a promising new avenue for the development of important new aromatic compounds with a broad range of applications.
Author: Zahra Taherinia
Publisher: Royal Society of Chemistry
ISBN: 1837671796
Category : Science
Languages : en
Pages : 334
Get Book Here
Book Description
Author: Saki Ichikawa
Publisher:
ISBN:
Category :
Languages : en
Pages : 349
Get Book Here
Book Description
The studies presented in this dissertation are regarding the development of new methods for copper-catalyzed carbon-heteroatom bond formations, including asymmetric hydroamination and continuous-flow aromatic Finkelstein reaction. The first part of this dissertation focuses on the development of copper-catalyzed asymmetric hydroamination reactions to access various classes of enantioenriched amines. This includes the development of a broadly applicable hydroamination protocol for the synthesis of enantioenriched N-arylamines (Chapter 1) and 1,2- diamines (Chapter 2). The second part of this dissertation describes the development of copper-catalyzed aromatic Finkelstein reaction under continuous-flow conditions (Chapter 3). Part I. Chapter 1. A Modified System for the Synthesis of Enantioenriched N-Arylamines through Copper-Catalyzed Hydroamination Despite significant recent progress in copper-catalyzed enantioselective hydroamination chemistry, the synthesis of chiral N-arylamines, which are frequently found in natural products and pharmaceuticals, has not been realized. Initial experiments with N-arylhydroxylamine ester electrophiles were unsuccessful and instead, their reduction, in the presence of copper hydride (CuH) catalysts, was observed. We detail key modifications of our previously reported hydroamination protocols that led to broadly applicable conditions for the enantioselective net addition of secondary anilines across the double bond of styrenes, 1,1 -disubstituted alkenes, and terminal alkenes. NMR studies suggest that suppression of the undesired reduction pathway is the basis for the dramatic improvements in yield under this new protocol. Chapter 2. Regio- and Enantioselective Synthesis of 1,2-Diamine Derivatives by Copper- Catalyzed Hydroamination A highly regio- and enantioselective synthesis of 1,2-diamines using [gamma]-substituted allylic pivalamides via copper-catalyzed hydroamination is reported. The N-pivaloyl group is essential, both in facilitating the hydrocupration step and in suppressing the unproductive [beta]-elimination from the alkylcopper intermediate. This synthetic approach enables an efficient construction of chiral, differentially protected, vicinal diamines under mild conditions with broad functional group tolerance. Part II. Chapter 3. Rapid and Efficient Copper-Catalyzed Finkelstein Reaction of (Hetero)Aromatics under Continuous-Flow Conditions A general, rapid, and efficient method for the copper-catalyzed Finkelstein reaction of (hetero)aromatics has been developed using continuous flow to generate a variety of aryl iodides. The described method can tolerate a broad range of functional groups, including N-H and O-H groups. Additionally, in lieu of isolation, the aryl iodide products in solution can be directly used in two distinct multistep continuous-flow processes (amidation or Mg-I exchange/nucleophilic addition) to demonstrate the flexibility of this method.
