DOCSLIB.ORG

Recyclable Catalysts for Alkyne Functionalization

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Recyclable Catalysts for Alkyne Functionalization molecules Review Recyclable Catalysts for Alkyne Functionalization Leslie Trigoura 1,2 , Yalan Xing 1,* and Bhanu P. S. Chauhan 2,* 1 Department of Chemistry, William Paterson University of New Jersey, 300 Pompton Road, Wayne, NJ 07470, USA; [email protected] 2 Engineered Nanomaterials Laboratory, Department of Chemistry, William Paterson University of New Jersey, 300 Pompton Road, Wayne, NJ 07470, USA * Correspondence: [email protected] (Y.X.); [email protected] (B.P.S.C.); Tel.: +1-973-720-2470 (B.P.S.C.) Abstract: In this review, we present an assessment of recent advances in alkyne functionalization reactions, classified according to different classes of recyclable catalysts. In this work, we have in- corporated and reviewed the activity and selectivity of recyclable catalytic systems such as polysiloxane- encapsulated novel metal nanoparticle-based catalysts, silica–copper-supported nanocatalysts, graphitic carbon-supported nanocatalysts, metal organic framework (MOF) catalysts, porous organic frame- work (POP) catalysts, bio-material-supported catalysts, and metal/solvent free recyclable catalysts. In addition, several alkyne functionalization reactions have been elucidated to demonstrate the success and efficiency of recyclable catalysts. In addition, this review also provides the fundamental knowl- edge required for utilization of green catalysts, which can combine the advantageous features of both homogeneous (catalyst modulation) and heterogeneous (catalyst recycling) catalysis. Keywords: green catalysts; nanosystems; nanoscale catalysts; catalyst modulation; alkyne functional- ization; coupling reactions Citation: Trigoura, L.; Xing, Y.; 1. Introduction Chauhan, B.P.S. Recyclable Catalysts for Alkyne Functionalization. Alkyne functionalization methods constitute one of the most relevant topics in organic Molecules 2021, 26, 3525. https:// synthesis and has resulted in numerous advancements over several years. Alkynes are doi.org/10.3390/molecules26123525 readily available building blocks for organic synthesis because carbon–carbon multiple bonds can be functionalized to a myriad of structures. Direct functionalization of alkynes Academic Editor: Chiara Bisio is a powerful approach for the construction of various complex organic structures because of its high efficiency in the cascade formation of carbon–carbon and carbon–heteroatom Received: 5 May 2021 bonds [1–5]. Accepted: 4 June 2021 There is a key interest in developing new systems and conditions to improve the Published: 9 June 2021 efficiency for these reactions. Apart from the tremendous attention that this subject in chemistry has achieved, there are still certain limitations that prevent its advanced adoption Publisher’s Note: MDPI stays neutral for applications in industry. Some of these drawbacks include cost, efficiency, use of with regard to jurisdictional claims in toxic metals, tedious catalyst recoverability, metal leaching, low regioselectivity, poor published maps and institutional affil- functional group tolerance, the need for excess amounts of reagents, and low catalytic iations. activity and stability. The recyclability of the catalysts in organic synthesis is important to study, especially when looking to the applicability of reactions in industrial settings. Herein, we have provided a comprehensive survey and analysis of the recent and developmental work Copyright: © 2021 by the authors. in alkyne functionalization using a variety of different classes of recyclable catalysts. Licensee MDPI, Basel, Switzerland. Each of the reported catalysts has been reported to result in transformations in high This article is an open access article yields and to have the ability to be recovered and recycled from the reaction, up to or distributed under the terms and more than four times. The catalytic activity of each catalytic system reported seems to conditions of the Creative Commons maintain its stability, even after reuse, and has been shown to perform competitively when Attribution (CC BY) license (https:// compared to traditional methods used to carry out the same proposed reactions. In this creativecommons.org/licenses/by/ review, we have highlighted polysiloxane-encapsulated novel metal nanoparticle-based 4.0/). Molecules 2021, 26, 3525. https://doi.org/10.3390/molecules26123525 https://www.mdpi.com/journal/molecules MoleculesMolecules 20212021,, 2626,, xx FORFOR PEERPEER REVIEWREVIEW 22 ofof 2222 Molecules 2021, 26, 3525 2 of 22 traditionaltraditional methodsmethods usedused toto carrycarry outout thethe sasameme proposedproposed reactions.reactions. InIn thisthis review,review, wewe havehave highlightedhighlighted polysiloxane-encapsulatedpolysiloxane-encapsulated novelnovel metalmetal nanoparticle-basednanoparticle-based catalysts,catalysts, sil-sil- ica–copper-supportedica–copper-supportedcatalysts, silica–copper-supported nanocatalysts,nanocatalysts, nanocatalysts, graphiticgraphitic carbon-supportedcarbon-supported graphitic carbon-supported nanocatalysts,nanocatalysts, nanocatalysts, metalmetal or-or- ganicganicmetal framework organicframework framework (MOF)(MOF) catalysts, (MOF)catalysts, catalysts, porousporous porousorganicorganic organic frameworkframework framework (POP)(POP) (POP) catalysts,catalysts, catalysts, bio-bio- material-supportedmaterial-supportedbiomaterial-supported catalysts,catalysts, catalysts, andand and metal-/solvent-freemetal-/solvent-free metal-/solvent-free recyclablerecyclable recyclable catalystscatalysts catalysts (Figure(Figure (Figure 1).1). 1). FigureFigureFigure 1.1. CategoriesCategoriesCategories ofof of recyclablerecyclable recyclable catalystscatalysts inin alkynealkyne functionalizationfunctionalization highlightedhighlighted inin thisthis review. review. Additionally,Additionally, amongst amongst the the highlightedhighlighted catalysts, catalysts, aa varietyvariety ofof alkynealkyne functionalizationfunctionalization functionalization reactionsreactionsreactions havehave beenbeen studiedstudied toto yieldyield severalseveral several functionalizedfunctionalized functionalized products,products, suchsuch asas symmetricalsymmetrical andand unsymmetricalunsymmetrical 1,3-diyne1,3-diyne motifs,motifs, vinylvinyl silasila silanes,nes,nes, dihalogenateddihalogenated ketones,ketones, cross-coupled cross-coupled functionalizedfunctionalizedfunctionalized alkynes,alkynes, 1,4-di1,4-di 1,4-disubstituted-1,2,3-triazoles,substituted-1,2,3-triasubstituted-1,2,3-triazoles,zoles, polytriazoles, polytriazoles, propargylamines, propargylamines, 1,2,3-triazoles,1,2,3-triazoles, 1-haloalkynes,1-haloalkynes, alkylidenefuranones, alkylidenefuranones, thioesters, thioesters, and and others others (Figure (Figure 2 2).2).). Figure 2. The wide array of alkyne functionalized products achieved through the reactions focused on in this review via recyclable catalysts. Molecules 2021, 26, x FOR PEER REVIEW 3 of 22 Molecules 2021, 26, 3525 3 of 22 Figure 2. The wide array of alkyne functionalized products achieved through the reactions fo- cused on in this review via recyclable catalysts. TheThe successful successful replacement replacement of of single-use single-use cata catalystslysts with with recyclable recyclable catalysts has been demonstrateddemonstrated throughout throughout all all the the mentioned mentioned work work,, allowing allowing the the reactions reactions to have have a a broad broad substratesubstrate scope, goodgood regioselectivity, regioselectivity, and and excellent excellent yields, yields, as wouldas would any traditionallyany traditionally used usedcatalyst, catalyst, while while simultaneously simultaneously providing providing the advantages the advantages of simple of simple removal removal and reusability. and re- usability.Although Although previously previously published published reviews may reviews highlight may highlight the use of the recyclable use of recyclable catalysts, cat- the alysts,purpose the of purpose this review of this will review be to showcase will be to these showcase new andthese developing new and developing catalytic approaches catalytic approachesin the field ofin alkynethe field functionalization. of alkyne functionalization. 2.2. Catalyst Catalyst Potential Potential and and Recyclability Recyclability 2.1.2.1. Polysiloxane Polysiloxane Encapsulated Encapsulated Novel Novel Metal Metal Nanoparticle-Based Nanoparticle-Based Catalysts Catalysts Creation of recyclable catalysts permits on onee to help help develop develop green green chemical chemical processes processes whichwhich at at a a larger larger scale scale positively positively impact impact our our environment environment as well as well as contribute as contribute to the to de- the velopmentdevelopment of ofa new a new economy. economy. Chauhan Chauhan et et al al.. have have been been developing developing new new green green catalysts catalysts whichwhich have have shown shown unparalleled unparalleled efficiency efficiency and selectivity selectivity in various various transformations transformations such asas hydrosilylation, hydrosilylation, polymer polymer modification, modification, oxidative oxidative coupling coupling reactions and alcoholysis processesprocesses of of hydrosilanes, hydrosilanes, to to name name a few. a few. The The basic basic framework framework in these in these new newcatalysts catalysts piv- otspivots on the on thefact fact that that support support materials materials are are cr createdeated in in such such a afashion fashion that that these these catalysts behavebehave as
Load more

Recommended publications
  • Advances in Metal-Catalyzed Cross-Coupling Reactions of Halogenated Quinazolinones and Their Quinazoline Derivatives
    Molecules 2014, 19, 17435-17463; doi:10.3390/molecules191117435 OPEN ACCESS molecules ISSN 1420-3049 www.mdpi.com/journal/molecules Review Advances in Metal-Catalyzed Cross-Coupling Reactions of Halogenated Quinazolinones and Their Quinazoline Derivatives Malose Jack Mphahlele * and Marole Maria Maluleka Department of Chemistry, College of Science, Engineering and Technology, University of South Africa, P.O. Box 392, Pretoria 0003, South Africa; E-Mail: [email protected] * Author to whom correspondence should be addressed; E-Mail: [email protected]; Tel.: +27-12-429-8805; Fax: +27-12-429-8549. External Editor: Derek J. McPhee Received: 26 August 2014; in revised form: 10 October 2014 / Accepted: 21 October 2014 / Published: 29 October 2014 Abstract: Halogenated quinazolinones and quinazolines are versatile synthetic intermediates for the metal-catalyzed carbon–carbon bond formation reactions such as the Kumada, Stille, Negishi, Sonogashira, Suzuki-Miyaura and Heck cross-coupling reactions or carbon-heteroatom bond formation via the Buchwald-Hartwig cross-coupling to yield novel polysubstituted derivatives. This review presents an overview of the application of these methods on halogenated quinazolin-4-ones and their quinazolines to generate novel polysubstituted derivatives. Keywords: halogenoquinazolin-4-ones; halogenoquinazolines; cross-coupling reactions 1. Introduction and Scope In recent years, the development of strategies to efficiently functionalize presynthesized halogenated quinazolinones and quinazolines or their tosylate derivatives via metal-catalyzed cross-coupling reactions to afford novel polycarbo- or polyheteroatom-substituted derivatives with potential application in pharmaceuticals and materials has attracted considerable interest. The 3-substituted 2,6-diarylquinazolin-4(3H)-ones 1 and 2 (Figure 1), for example, were previously prepared via Suzuki-Miyaura cross-coupling of the corresponding 6-halogenated 4(3H)-oxo precursors and were found to be ghrelin receptor and vasopressin V1b receptor antagonists, respectively [1,2].
    [Show full text]
  • Part I Principles of Enzyme Catalysis
    j1 Part I Principles of Enzyme Catalysis Enzyme Catalysis in Organic Synthesis, Third Edition. Edited by Karlheinz Drauz, Harald Groger,€ and Oliver May. Ó 2012 Wiley-VCH Verlag GmbH & Co. KGaA. Published 2012 by Wiley-VCH Verlag GmbH & Co. KGaA. j3 1 Introduction – Principles and Historical Landmarks of Enzyme Catalysis in Organic Synthesis Harald Gr€oger and Yasuhisa Asano 1.1 General Remarks Enzyme catalysis in organic synthesis – behind this term stands a technology that today is widely recognized as a first choice opportunity in the preparation of a wide range of chemical compounds. Notably, this is true not only for academic syntheses but also for industrial-scale applications [1]. For numerous molecules the synthetic routes based on enzyme catalysis have turned out to be competitive (and often superior!) compared with classic chemicalaswellaschemocatalyticsynthetic approaches. Thus, enzymatic catalysis is increasingly recognized by organic chemists in both academia and industry as an attractive synthetic tool besides the traditional organic disciplines such as classic synthesis, metal catalysis, and organocatalysis [2]. By means of enzymes a broad range of transformations relevant in organic chemistry can be catalyzed, including, for example, redox reactions, carbon–carbon bond forming reactions, and hydrolytic reactions. Nonetheless, for a long time enzyme catalysis was not realized as a first choice option in organic synthesis. Organic chemists did not use enzymes as catalysts for their envisioned syntheses because of observed (or assumed) disadvantages such as narrow substrate range, limited stability of enzymes under organic reaction conditions, low efficiency when using wild-type strains, and diluted substrate and product solutions, thus leading to non-satisfactory volumetric productivities.
    [Show full text]
  • Advances in Cross-Coupling Reactions
    molecules Editorial Advances in Cross-Coupling Reactions José Pérez Sestelo * and Luis A. Sarandeses * Centro de Investigaciones Científicas Avanzadas (CICA) and Departamento de Química, Universidade da Coruña, E-15071 A Coruña, Spain * Correspondence: [email protected] (J.P.S.); [email protected] (L.A.S.); Tel.: +34-881-012-041 (J.P.S.); +34-881-012-174 (L.A.S.) Received: 28 September 2020; Accepted: 30 September 2020; Published: 1 October 2020 Cross-coupling reactions stand among the most important reactions in chemistry [1,2]. Nowadays, they are a highly valuable synthetic tool used for the preparation of a wide variety of organic compounds, from natural and synthetic bioactive compounds to new organic materials, in all fields of chemistry [3]. Almost 50 years from its discovery, the research in this topic remains active, and important progresses are accomplished every year. For this reason, we believe that a Special Issue on this topic is of general interest for the chemistry community. Advances in cross-coupling reactions have been developed with the aim to expand the synthetic utility of the methodology, through the involvement of new components, reaction conditions, and therefore, novel synthetic applications [4]. Although initially the term “cross-coupling” referred to the reaction of an organometallic reagent with an unsaturated organic halide or pseudohalide under transition metal catalysis, currently the definition is much more general and applies to reactions involving other components, conditions, and more complex synthetic transformations. In addition to the well-known and recognized cross-coupling reactions using organoboron (Suzuki-Miyaura), organotin (Stille), organozinc (Negishi), or organosilicon (Hiyama) nucleophiles, reactions involving other organometallic reagents such as organoindium [5,6], organolithium [7], and Grignard reagents [8] are now useful synthetic alternatives.
    [Show full text]
  • Recent Advances in Microwave-Assisted Copper-Catalyzed Cross-Coupling Reactions
    catalysts Review Recent Advances in Microwave-Assisted Copper-Catalyzed Cross-Coupling Reactions Younis Baqi Department of Chemistry, College of Science, Sultan Qaboos University, P.O. Box 36, Muscat 123, Oman; [email protected]; Tel.: +968-2414-1473 Abstract: Cross-coupling reactions furnishing carbon–carbon (C–C) and carbon–heteroatom (C–X) bond is one of the most challenging tasks in organic syntheses. The early developed reaction protocols by Ullmann, Ullman–Goldberg, Cadiot–Chodkiewicz, Castro–Stephens, and Corey–House, utilizing elemental copper or its salts as catalyst have, for decades, attracted and inspired scientists. However, these reactions were suffering from the range of functional groups tolerated as well as severely restricted by the harsh reaction conditions often required high temperatures (150–200 ◦C) for extended reaction time. Enormous efforts have been paid to develop and achieve more sustainable reaction conditions by applying the microwave irradiation. The use of controlled microwave heating dramatically reduces the time required and therefore resulting in increase in the yield as well as the efficiency of the reaction. This review is mainly focuses on the recent advances and applications of copper catalyzed cross-coupling generation of carbon–carbon and carbon–heteroatom bond under microwave technology. Keywords: cross-coupling reaction; Cu catalyst; microwave irradiation; methodology; synthesis 1. Introduction Carbon–carbon (C–C) and carbon–heteroatom (C–X) bond formations through cross- Citation: Baqi, Y. Recent Advances in coupling reactions represents as one of the most useful strategy in the synthetic organic Microwave-Assisted chemistry, hence many procedures and methodologies have been developed and published Copper-Catalyzed Cross-Coupling in the literature.
    [Show full text]
  • Organometallic Chemistry BASIC PRINCIPLES, APPLICATIONS, and a FEW CASE STUDIES
    Safety Moment TYLER LAB GROUP MEETING 1 Safety Moment TYLER LAB GROUP MEETING 2 Metal Hydrides: Benchtop vs. Box Hydride = :H- Hydrides are powerful Lewis bases and reducing agent ◦ Exothermically form H2 (this should scare you) ◦ Heating leads to faster reactivity ◦ H evolution leads to rapid increase in pressure2 ◦ Uncontrolled reactions easily cause runaway exotherm, class D fire, explosion, and death/unemployment LiAlH is the #1 chemical cause of fatality in chemical4 industry 3 Metal Hydrides: “I want to commit the murder I was imprisoned for†.” LiAlH4 ◦ Insanely irritating (serious safety hazard) ◦ Extremely moisture sensitive (don’t leave out for >2 minutes) ◦ Ethereal mixtures are pyrophoric! DiBuAl-H ◦ Pyrophoric – it will explode upon exposure to oxygen NaEt3BH ◦ Pyrophoric in solution LiH and NaH ◦ Can be handled on the benchtop (not >2 minutes) ◦ Parrafin oil dispersions much safer KH ◦ Pyrophoric if not in a dispersion ◦ Handle with extreme care! † Sirius Black, Harry Potter and the Prisoner of Azkaban 4 Metal Hydrides: “I want to commit the murder I was imprisoned for†.” CaH2 ◦ Very safe to handle on the benchtop Pt-H, Pd-H, Ni-H ◦ All very pyrophoric NaBH4 ◦ Very safe in general Other hydrides ◦ Treat as pyrophoric ◦ Transition metal hydrides vary in hydridic strength ◦ General rule of thumb: if it does hydrogenations, it is probably pyrophoric ◦ If they’re in organics of any kind, they are probably pyrophoric † Sirius Black, Harry Potter and the Prisoner of Azkaban 5 Organometallic Chemistry BASIC PRINCIPLES, APPLICATIONS,
    [Show full text]
  • 6.-Organic-Chemistry-I-Edexcel.Pdf
    6: Organic Chemistry I 6A. Introduction to Organic Chemistry Basic definitions Hydrocarbon is a compound consisting of hydrogen and carbon only to know Saturated: Contain single carbon-carbon bonds only Unsaturated : Contains a C=C double bond Molecular formula: The formula which shows the actual number of each type of atom Empirical formula: shows the simplest whole number ratio of atoms of each element in the compound General formula: algebraic formula for a homologous series e.g. CnH2n Structural formula shows the minimal detail that shows the arrangement of atoms in a molecule, eg for butane: CH3CH2CH2CH3 or CH3(CH2)2CH3, Displayed formula: show all the covalent bonds present in a molecule Drawing Displayed formulae Remember that the shape around the carbon atom in saturated hydrocarbons is H H H H When drawing organic tetrahedral and the bond angle is 109.5o H C C C C H compounds add the hydrogen atoms so that H H H H H H C H each carbon has 4 bonds H C C H H H H Skeletal formula shows the simplified organic formula, shown by removing hydrogen atoms from alkyl chains, leaving just a carbon skeleton and associated functional Groups. OH But-2-ene Butan-1-ol 2-methylbutane cyclohexane cyclohexene N Goalby chemrevise.org 1 Homologous series are families of organic compounds with the same functional group and same general formula. •They show a gradual change in physical properties (e.g. boiling point). • Each member differs by CH2 from the last. • same chemical properties. Functional group is an atom or group of atoms which when present
    [Show full text]
  • Organic Reaction Worksheet
    Name _____________________________________ Date _________ Organic Reaction Worksheet 1. Fill in the table below. Be sure to complete the example reaction as well as fill in all other blanks. Be complete in your answers. Organic Description Example Reaction a. Addition CH2=CH2 + Cl2 → b.. A halogen replaces a I hydrogen on a | saturated alkane CH3CH2CH3 + ____→ CH3CHCH3 + HI c. Join many small molecules into one large molecule d. C6H12O6 + Yeast → CH3CH2OH + CO2 e. Fat + base → ____________________ f. CH3CH2COOH + CH3OH → ___________________________ + __________ g. C3H8 + 5 O2 → 3CO2 + 4H2O h. Break down large C20H42 → C8H16 + 2C3H8 hydrocarbons with heat, pressure and/or catalyst into smaller, more useful sizes 2. The process of joining many small molecules into larger molecules is called (1) neutralization (2) polymerization (3) saponification (4) substitution 3. In which reaction is soap a product? (1) addition (2) substitution (3) saponification (4) polymerization 4. Given the equation: C2H6 + Cl2 ---> C2H5Cl + HCl This reaction is best described as 1) addition involving a saturated hydrocarbon (2) addition involving an unsaturated hydrocarbon (3) substitution involving a saturated hydrocarbon (4) substitution involving an unsaturated hydrocarbon 5. Base your answers to questions a. through c. on the information below. Many artificial flavorings are prepared using the type of organic reaction shown below. a. What is the name of this organic reaction? __________________________ b. To what class of organic compounds does reactant 2 belong? ______________ c. Draw the structural formula of an isomer of reactant 2. 6. In the space to the right of the reactants and arrow draw the structural formula for the product of the reaction shown.
    [Show full text]
  • 1 CHEM 344 Organometallic Chemistry Practice Problems
    CHEM 344 Organometallic Chemistry Practice Problems (not for credit) Name (print): TA name (print): _____________ 1) Careful choice of solvent is essential for the successful generation and reaction of a Grignard reagent. a) Explain why anhydrous diethyl ether and tetrahydrofuran (THF) are common solvents for the generation of Grignard reagents. b) Show the major product(s) of the reaction of 4-methylphenylmagnesium bromide (prepared in anhydrous diethyl ether) with benzophenone (dissolved in either ethanol, acetone, or diethyl ether). Assume acidic workup in each case. 1 2) The reaction of PhMgBr with cyclohexanone (C6H10O) followed by addition of sulfuric acid produces 1-phenylcyclohexene (C12H14) as shown below. The crude reaction mixture was analyzed by GC-mass spectrometry. Use the GC-MS data on the next page to identify the components of the crude product mixture and assess its purity. Draw a plausible electron-pushing mechanism for the formation of the major and minor products starting from bromobenzene. 2 3 3) 3) Show the product and justify the chemoselectivity of each of the following oxidative addition reactions. Show the oxidation state of the metal in the product. The table of C-X bond dissociation enthalpies of halobenzenes may be useful. a) b) c) C–X Bond Dissociation Enthalpies ° Ph–X H C–X (kcal/mol) 127 97 84 67 113 4 4) Transmetallation follows oxidative addition in a typical Pd-catalyzed coupling cycle. The process of transmetallation can be described by the following equilibrium: The process is thermodynamically favorable for the production of M-R if XM > XM' (X = Pauling electronegativity, M/M' = metal, R = organic group, X= halide).
    [Show full text]
  • DEPARTMENT of CHEMISTRY for M.Sc in Chemistry
    DEPARTMENT OF CHEMISTRY SCHEME OF INSTRUCTIONS AND SYLLABUS (Course Book) FOR M.Sc in Chemistry Visvesvaraya National Institute of Technology, Nagpur July 2015 1 Contents Sr. No. Title Page No. 1 General Information about the department 3 2 Brief about M.Sc program 3 3 Vision and mission 4 4 Credit requirements 5 5 Detailed scheme 6 6 Detailed syllabus 7-31 2 1. General Information about the department Science is basic foundation of any technological and engineering creation. In view of the changing scenario at national and international level in field of Science and Technology, there is great demand for basic sciences with considerable knowledge of its applications. VNIT is committed to high academic standards. The M.Sc. courses are designed for four semesters (two years) in such a way that a good basic foundation of subjects is laid and applications along with recent developments are covered. Relative grading will be followed and credits will be allotted based on academic performance. Students will also get theoretical and practical knowledge of computer programming. These M.Sc. programmes provide opportunity to make career in R&D, industries and academic institutions. Opportunity for the placement may be provided by the Institute. 2. Brief about M.Sc program: Department of Chemistry offers M.Sc. (Chemistry) program which gives good foundation of basics and research component through practical skills, which in turn will provide excellent job prospects in Academics, Industries and other field of interest. M.Sc. (Chemistry) will provide competence to tackle frontier area in Green chemistry, supramolecular chemistry, Sensors, Advanced materials and Advanced organic chemistry.
    [Show full text]
  • Bio-Organic Mechanism Game – Simplistic Biochemical Structures and Simplistic Organic Reaction Mechanisms Are Used to Explain Common Biochemical Transformations
    1 Bio-Organic Mechanism Game – Simplistic biochemical structures and simplistic organic reaction mechanisms are used to explain common biochemical transformations. Simplified biochemical molecules are presented first. Many biomolecules have a somewhat complex structure that makes it difficult to write out step by step mechanisms. However, if we simplify those structures to the essential parts necessary to explain the mechanistic chemistry of each step, it becomes much easier to consider each step through an important cycle. I have proposed possible simplified structures that are used in the later examples of biochem cycles and problems. The usual strategy in biochem cycles is to just write names, or perhaps, names and a structure. Occasionally a few mechanistic steps are suggested, but almost never is a detailed sequence of mechanistic steps provided. Since it is hard to find such detailed mechanistic steps anywhere (sometimes they are not known) our proposed steps are, of necessity, somewhat speculative. In this book we are not looking for perfection, which is not possible, but for sound organic logic that is consistent with the biochemical examples presented below. There is great satisfaction in blending organic knowledge with real life reactions that help explain how life works. In working through some of the problems, you may develop an alternative mechanism that is just as good, or even better than the one I have proposed. If you do, I hope you will share it with me and if an improved version of this book ever gets written I can include it the next edition (and give you credit). It is almost certain that I have made some errors and I would appreciate it if you would let me know about them.
    [Show full text]
  • Course CHEM 2323.HN1 Organic Chemistry I Professor Michael Biewer Term Fall 2015 Meetings T/R 8:30-9:45 AM, ATC 2.101
    Course CHEM 2323.HN1 Organic Chemistry I Professor Michael Biewer Term Fall 2015 Meetings T/R 8:30-9:45 AM, ATC 2.101 Professor’s Contact Information Office Phone 972-883-2811 Office Location BE 3.326 Email Address [email protected] Office Hours T/R 1-2 General Course Information Pre-requisites, Co-requisites, & CHEM 1312 General Chemistry II other restrictions This course is designed to provide a unified overview of fundamental organic chemistry for science majors. Students who successfully complete this course acquire an integrated understanding of molecular architecture, molecular transformations, reaction energetics and mechanisms, synthetic strategy, and structure determination. Tests will be given on the dates given in the syllabus during class time. There will be three quizzes given on the days indicated in the syllabus. You are allowed to drop your lowest quiz score. Students often view organic chemistry as a difficult course. I strongly recommend Course that everyone attempt to keep up with the class as it proceeds. This is not a course Description where it is easy to ‘cram’ for a test. Students invariably do better once they learn how to visualize organic molecules, and reactions, in three dimensions. If you know this is a problem I recommend using molecular models to try and view the molecules. Also try to realize that this is not a memorization course. While some memorization is unavoidable, the purpose of this course is to teach everyone the underlying basic principles that drive an organic reaction. Once these principles are handled a student will be able to understand, and predict, why any reaction occurs.
    [Show full text]
  • Palladium-Catalyzed Biaryl Coupling Using PEPPSI Under Aqueous Microwave Conditions
    Palladium-Catalyzed Biaryl Coupling Using PEPPSI Under Aqueous Microwave Conditions Introduction The 2010 Nobel Prize in Chemistry was awarded to Richard Heck, Ei-ichi Negishi, and Akira Suzuki for their contributions to the use of palladium-catalyzed cross coupling in organic synthesis.1 Each recipient of the prize developed a variant on the theme of forming a carbon- carbon bond between an aromatic compound (usually an aryl halide) and another aryl, vinyl, or alkynyl compound (Equation 1). (1) The reaction we will be focusing on in this lab is palladium-catalyzed biaryl coupling between an aryl halide and phenylboronic acid, commonly known as Suzuki Coupling. Since its discovery in the late 1970s,2 literally hundreds of ways have been developed to conduct this reaction under various conditions and with controllable selectivity.3 Regardless of which flavor of palladium catalyzed cross-coupling you choose to carry out, first step in the general cross-coupling mechanism is the same (Scheme 1). Starting with a palladium(0) species supported by some (usually strong field) ligand, the first Pd-R bond is formed through the oxidative addition of R-X to the metal atom, generating a Pd(II) compound. In Suzuki coupling, a Scheme 1. Suzuki Coupling Mechanism second Pd-C bond is then formed through transmetalation of an ’ activated R -BY2 species, resulting in a Pd(II) diaryl compound. Reductive elimination of a R-R’ species regenerates the Pd(0) compound and the cycle can begin again. There are many bases that can be used to activate the boronic acid or boronic ester, including potassium tert-butoxide, cesium carbonate, and cesium fluoride.
    [Show full text]