DOCSLIB.ORG

Synthesis, Characterization, and Application of 1,4-Dienylindiums Toward Skipped Dienes

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Synthesis, Characterization, and Application of 1,4-Dienylindiums Toward Skipped Dienes molecules Communication Regio- and Stereoselective Allylindation of Alkynes Using InBr3 and Allylic Silanes: Synthesis, Characterization, and Application of 1,4-Dienylindiums toward Skipped Dienes Yoshihiro Nishimoto 1,*, Junyi Yi 2, Tatsuaki Takata 2, Akio Baba 2 and Makoto Yasuda 2,* 1 Frontier Research Base for Global Young Researchers Center for Open Innovation Research and Education (COiRE), Graduate School of Engineering, Osaka University; Osaka 565-0871, Japan 2 Department of Applied Chemistry, Graduate School of Engineering, Osaka University; Osaka 565-0871, Japan; [email protected] (J.Y.); [email protected] (T.T.); [email protected] (A.B.) * Correspondence: [email protected] (Y.N.); [email protected] (M.Y.); Tel.: +81-6-6879-7386 (Y.N.); +81-6-6879-7384 (M.Y.) Received: 7 July 2018; Accepted: 27 July 2018; Published: 27 July 2018 Abstract: Regioselective anti-allylindation of alkynes was achieved using InBr3 and allylic silanes. Various types of alkynes and allylic silanes were applicable to the present allylindation. This sequential process used the generated 1,4-dienylindiums to establish novel synthetic methods for skipped dienes. The 1,4-dienylindiums were characterized by spectral analysis and treated with I2 to stereoselectively give 1-iodo-1,4-dienes. The Pd-catalyzed cross coupling of 1,4-dienylindium with iodobenzene successfully proceeded in a one-pot manner to afford the corresponding 1-aryl-1,4-diene. Keywords: indium; allylmetalation; alkyne; allylic silane 1. Introduction Carbometalation is an important synthetic method in organic synthesis because organometallic compounds are produced with an expansion of the carbon framework [1–7]. In particular, the allylmetalation of alkynes provides metalated skipped dienes (1,4-diene), which are effectively transformed to functionalized skipped dienes via sequential reactions [8–18]. Skipped diene units are present in many biologically important natural products, and are also versatile synthetic building blocks in organic synthesis [19–22]. Therefore, various types of allylmetalation of alkynes have been developed. However, most reported reactions involve a syn-addition to alkynes, and few reports have focused on anti-allylmetalation (Scheme1). Allylmagnesations via direct anti-addition of allylic Grignard reagent were also reported (Scheme1A,B), in which a directing group such as hydroxy and amino groups nearby the alkyne moiety are required [23–29]. Yamamoto reported an allylsilylation of simple alkynes with allylic silanes catalyzed by either HfCl4 or EtAlCl2-Me3SiCl (Scheme1C) [ 16,30–32]. However, the produced 1,4-dienyl trialkylsilanes cannot be applied to sequential transformations such as Hiyama coupling without activation by a strong base because of their low reactivity. In this context, we achieved regioselective anti-allylindation of simple alkynes using InBr3 and allylic silanes (Scheme1D). To the best of our knowledge, anti-allylindation of alkynes has never been established, while several syn-allylindations using allylic indiums have [13,33–39]. The 1,4-dienylindium compounds can be excellent precursors for functionalized skipped dienes due to their moderate reactivity and high compatibility with many functional groups. In fact, the 1,4-dienylindiums synthesized by the present allylindation can be easily transformed to functionalized skipped dienes by iodination or Pd-catalyzed cross coupling without the addition of bases in contrast to 1,4-dienylsilanes produced via allylsilylation. Molecules 2018, 23, 1884; doi:10.3390/molecules23081884 www.mdpi.com/journal/molecules Molecules 2018, 23, x 2 of 14 Moleculesskipped2018 dienes, 23, 1884 by iodination or Pd-catalyzed cross coupling without the addition of bases in contrast2 of 14 to 1,4-dienylsilanes produced via allylsilylation. SchemeScheme 1.1. AntiAnti-allylmetalation-allylmetalation ofof alkynes.alkynes. 2. Results 2. Results Recently, we reported regioselective anti-carbometalations of alkynes using organosilicon Recently, we reported regioselective anti-carbometalations of alkynes using organosilicon nucleophiles nucleophiles and metal halides such as InBr3 [40], GaBr3 [41], BiBr3 [42], ZnBr2 [43], and AlBr3 [44]. In and metal halides such as InBr3 [40], GaBr3 [41], BiBr3 [42], ZnBr2 [43], and AlBr3 [44]. In our established our established carbometalations, a metal halide directly activates an alkyne, and then an carbometalations, a metal halide directly activates an alkyne, and then an organosilicon nucleophile organosilicon nucleophile adds to the alkyne from an opposite site of the metal halide. Therefore, we adds to the alkyne from an opposite site of the metal halide. Therefore, we applied a combination of applied a combination of indium trihalides and allylic silanes to establish anti-allylindation of indium trihalides and allylic silanes to establish anti-allylindation of alkynes. First, various indium salts alkynes. First, various indium salts were investigated for the reaction using alkyne 1a and methallyl were investigated for the reaction using alkyne 1a and methallyl trimethylsilane 2a (Table1). InBr 3, trimethylsilane 2a (Table 1). InBr3, 1a, and 2a were mixed in CH2Cl2, and then the reaction mixture 1a, and 2a were mixed in CH2Cl2, and then the reaction mixture was stirred at room temperature for was stirred at room temperature for 24 h. After an I◦2 solution in THF was added at −78 °C, alkenyl 24 h. After an I2 solution in THF was added at −78 C, alkenyl iodide 4aa was obtained as a single iodide 4aa was obtained as a single isomer in 89% yield (Entry 1). An iodine group was introduced isomer in 89% yield (Entry 1). An iodine group was introduced exclusively cis to the allylic group. exclusively cis to the allylic group. The production of 4aa by quenching with I2 suggested that anti- The production of 4aa by quenching with I2 suggested that anti-allylindation regioselectively proceeded allylindation regioselectively proceeded to give the corresponding 1,4-dienylindium 3aa. The use of to give the corresponding 1,4-dienylindium 3aa. The use of InCl3 instead of InBr3 afforded 4aa in a 42% InCl3 instead of InBr3 afforded 4aa in a 42% yield (Entry 2). On the other hand, examinations using yield (Entry 2). On the other hand, examinations using InF3, InI3, and In(OTf)3 resulted in no reaction InF3, InI3, and In(OTf)3 resulted in no reaction (Entries 3–5). The thermodynamic stability of a (Entries 3–5). The thermodynamic stability of a generated side product Me3SiX might influence the driving generated side product Me3SiX might influence the driving force of the reaction. An investigation of force of the reaction. An investigation of the solvent effect was carried out. The reaction performed in the solvent effect was carried out. The reaction performed in non-polar solvents such as toluene non-polar solvents such as toluene resulted in no product because InBr3 did not dissolve the solvent resulted in no product because InBr3 did not dissolve the solvent (Entry 6). Polar solvents such as (Entry 6). Polar solvents such as Et2O, CH3CN, and THF were not suitable to the present allylindation Et2O, CH3CN, and THF were not suitable to the present allylindation because of the deactivation of because of the deactivation of InBr3 by the solvent coordination (Entries 7–9). InBr3 by the solvent coordination (Entries 7–9). MoleculesMolecules 2018, 23 2018, x , 23, x 3 of 14 3 of 14 MoleculesMolecules 2018, 23 2018, x , 23, x 3 of 14 3 of 14 Molecules 2018, 23, x 3 of 14 Table Table1. Optimization 1. Optimization of reaction of reaction condit conditions forions carboindation for carboindation of alkyne of alkyne 1a with 1a allylic with allylicsilane silane2a a. 2a a. Molecules 2018 23 a a Molecules Table2018, 23 Table1., x 1884Optimization 1. Optimization of reaction of reaction condit conditions forions carboindation for carboindation of alkyne of alkyne 1a with 1a allylic with allylicsilane silane2a 3. of 2a 14 . Table 1. Optimization of reaction conditions for carboindation of alkyne 1a with allylic silane 2a a. Table 1. Optimization of reaction conditions for carboindation of alkyne 1a with allylic silane 2a a. Table 1. Optimization of reaction conditions for carboindation of alkyne 1a with allylic silane 2a a. Entry InX3 Solvent Yield/% Entry InX3 Solvent Yield/% EntryEntry InX3 InX3 SolventSolvent Yield/%Yield/% Entry1 1 InXInBr3 3 InBr3 SolventCH2ClCH 2 2Cl2 Yield/%89 89 3 2 2 1 1 InBr3 InBr CH2ClCH2 Cl 89 89 b b 3 2 2 12 2 b InBrInCl3 InCl3 CHCH2ClCl2CH 2Cl2 8942 42 Entry2 b 2 EntryInXInCl3 3 InCl InX33 SolventSolventCH2ClCH 2 Yield/%2Cl2 Yield/%42 42 2 b3 3 InClInF3 3 InF3 CHCH2Cl2Cl2CH 2 2Cl2 420 0 3 3 InF3 2 2CH2Cl2 0 1 3 1InBrInF 3 InBr3 CHCH2CHClCl22Cl 2 89 890 4 InI3 3 CH2Cl2 2 2 0 3b 4 bInF3 InI CH2Cl2CH Cl 0 0 2 4 4 2 InClInI3 3 InIInCl3 3 CHCH2CHCl2Cl22Cl2CH 2 2Cl422 420 0 5 In(OTf)3 CH2Cl2 0 4 5 3InI3 In(OTf) InF 3 CHCHCl2Cl2CH 2Cl0 2 0 0 3 5 5 In(OTf)InF3 In(OTf)3 3 3 CH2CH2Cl22Cl2CH 2 2Cl2 0 0 0 3 5 6 6 In(OTf)4InBr 3 InBr InI33 CHCHtoluene2Cl2Cl2 2toluene 0 0 0 0 4 6 6 InIInBr3 3 InBr3 CHtoluene2Cl2toluene 0 0 0 6 7 7 5InBrInBr3 3 In(OTf)InBr3 3 CHtoluene2ClEt22O Et2O0 0 0 0 5 7 7 In(OTf)6InBr3 InBr InBr3 tolueneCHEt2Cl2O2 Et2O 0 0 0 0 8 8 InBr3 3 InBr33 CH2 3CNCH 3CN 0 0 7 InBr 3 Et O 3 0 6 8 8 7InBrInBr3 3 InBr InBr3 EttolueneCH2O3CNCH CN 0 0 0 0 8 9 9 InBrInBr3 3 InBr3 CHTHF3CN THF 0 0 0 7 9 8InBr3 3 InBr InBr33 CH3EtCN2O THF 0 0 0 a 9 InBr THF 0 InX3 (1a InX mmol),39 (1 mmol), alkyne alkyne 1a (1 mmol), 1a9InBr (1 mmol),3 allylic InBr allylicsilane silane2a (2THF mmol),THF 2a (2 mmol), solvent 0 solvent (1 mL), (1 room mL),0 temperature,room temperature, 24 24 a a InX3 (1 mmol), alkyne 1a (1 mmol),3 allylic3 silane 2a3 (2 mmol), solvent (1 mL), room temperature, 24 InX3 (1 mmol),8 alkyne 1a (1 mmol),InBr allylic silane 2a (2CH mmol),1CN solvent (1 mL), room0 temperature, 24 a h.
Load more

Recommended publications
  • Alkenes and Alkynes
    02/21/2019 CHAPTER FOUR Alkenes and Alkynes H N O I Cl C O C O Cl F3C C Cl C Cl Efavirenz Haloprogin (antiviral, AIDS therapeutic) (antifungal, antiseptic) Chapter 4 Table of Content * Unsaturated Hydrocarbons * Introduction and hybridization * Alkenes and Alkynes * Benzene and Phenyl groups * Structure of Alkenes, cis‐trans Isomerism * Nomenclature of Alkenes and Alkynes * Configuration cis/trans, and cis/trans Isomerism * Configuration E/Z * Physical Properties of Hydrocarbons * Acid‐Base Reactions of Hydrocarbons * pka and Hybridizations 1 02/21/2019 Unsaturated Hydrocarbons • Unsaturated Hydrocarbon: A hydrocarbon that contains one or more carbon‐carbon double or triple bonds or benzene‐like rings. – Alkene: contains a carbon‐carbon double bond and has the general formula CnH2n. – Alkyne: contains a carbon‐carbon triple bond and has the general formula CnH2n‐2. Introduction Alkenes ● Hydrocarbons containing C=C ● Old name: olefins • Steroids • Hormones • Biochemical regulators 2 02/21/2019 • Alkynes – Hydrocarbons containing C≡C – Common name: acetylenes Unsaturated Hydrocarbons • Arene: benzene and its derivatives (Ch 9) 3 02/21/2019 Benzene and Phenyl Groups • We do not study benzene and its derivatives until Chapter 9. – However, we show structural formulas of compounds containing a phenyl group before that time. – The phenyl group is not reactive under any of the conditions we describe in chapters 5‐8. Structure of Alkenes • The two carbon atoms of a double bond and the four atoms bonded to them lie in a plane, with bond angles of approximately 120°. 4 02/21/2019 Structure of Alkenes • Figure 4.1 According to the orbital overlap model, a double bond consists of one bond formed by overlap of sp2 hybrid orbitals and one bond formed by overlap of parallel 2p orbitals.
    [Show full text]
  • Introduction to Alkenes and Alkynes in an Alkane, All Covalent Bonds
    Introduction to Alkenes and Alkynes In an alkane, all covalent bonds between carbon were σ (σ bonds are defined as bonds where the electron density is symmetric about the internuclear axis) In an alkene, however, only three σ bonds are formed from the alkene carbon -the carbon thus adopts an sp2 hybridization Ethene (common name ethylene) has a molecular formula of CH2CH2 Each carbon is sp2 hybridized with a σ bond to two hydrogens and the other carbon Hybridized orbital allows stronger bonds due to more overlap H H C C H H Structure of Ethylene In addition to the σ framework of ethylene, each carbon has an atomic p orbital not used in hybridization The two p orbitals (each with one electron) overlap to form a π bond (p bonds are not symmetric about the internuclear axis) π bonds are not as strong as σ bonds (in ethylene, the σ bond is ~90 Kcal/mol and the π bond is ~66 Kcal/mol) Thus while σ bonds are stable and very few reactions occur with C-C bonds, π bonds are much more reactive and many reactions occur with C=C π bonds Nomenclature of Alkenes August Wilhelm Hofmann’s attempt for systematic hydrocarbon nomenclature (1866) Attempted to use a systematic name by naming all possible structures with 4 carbons Quartane a alkane C4H10 Quartyl C4H9 Quartene e alkene C4H8 Quartenyl C4H7 Quartine i alkine → alkyne C4H6 Quartinyl C4H5 Quartone o C4H4 Quartonyl C4H3 Quartune u C4H2 Quartunyl C4H1 Wanted to use Quart from the Latin for 4 – this method was not embraced and BUT has remained Used English order of vowels, however, to name the groups
    [Show full text]
  • Reactions of Aromatic Compounds Just Like an Alkene, Benzene Has Clouds of  Electrons Above and Below Its Sigma Bond Framework
    Reactions of Aromatic Compounds Just like an alkene, benzene has clouds of electrons above and below its sigma bond framework. Although the electrons are in a stable aromatic system, they are still available for reaction with strong electrophiles. This generates a carbocation which is resonance stabilized (but not aromatic). This cation is called a sigma complex because the electrophile is joined to the benzene ring through a new sigma bond. The sigma complex (also called an arenium ion) is not aromatic since it contains an sp3 carbon (which disrupts the required loop of p orbitals). Ch17 Reactions of Aromatic Compounds (landscape).docx Page1 The loss of aromaticity required to form the sigma complex explains the highly endothermic nature of the first step. (That is why we require strong electrophiles for reaction). The sigma complex wishes to regain its aromaticity, and it may do so by either a reversal of the first step (i.e. regenerate the starting material) or by loss of the proton on the sp3 carbon (leading to a substitution product). When a reaction proceeds this way, it is electrophilic aromatic substitution. There are a wide variety of electrophiles that can be introduced into a benzene ring in this way, and so electrophilic aromatic substitution is a very important method for the synthesis of substituted aromatic compounds. Ch17 Reactions of Aromatic Compounds (landscape).docx Page2 Bromination of Benzene Bromination follows the same general mechanism for the electrophilic aromatic substitution (EAS). Bromine itself is not electrophilic enough to react with benzene. But the addition of a strong Lewis acid (electron pair acceptor), such as FeBr3, catalyses the reaction, and leads to the substitution product.
    [Show full text]
  • Chapter 7 - Alkenes and Alkynes I
    Andrew Rosen Chapter 7 - Alkenes and Alkynes I 7.1 - Introduction - The simplest member of the alkenes has the common name of ethylene while the simplest member of the alkyne family has the common name of acetylene 7.2 - The (E)-(Z) System for Designating Alkene Diastereomers - To determine E or Z, look at the two groups attached to one carbon atom of the double bond and decide which has higher priority. Then, repeat this at the other carbon atom. This system is not used for cycloalkenes - If the two groups of higher priority are on the same side of the double bond, the alkene is designated Z. If the two groups of higher priority are on opposite sides of the double bond, the alkene is designated E - Hydrogenation is a syn/cis addition 7.3 - Relative Stabilities of Alkenes - The trans isomer is generally more stable than the cis isomer due to electron repulsions - The addition of hydrogen to an alkene, hydrogenation, is exothermic (heat of hydrogenation) - The greater number of attached alkyl groups, the greater the stability of an alkene 7.5 - Synthesis of Alkenes via Elimination Reactions, 7.6 - Dehydrohalogenation of Alkyl Halides How to Favor E2: - Reaction conditions that favor elimination by E1 should be avoided due to the highly competitive SN 1 mechanism - To favor E2, a secondary or tertiary alkyl halide should be used - If there is only a possibility for a primary alkyl halide, use a bulky base - Use a higher concentration of a strong and nonpolarizable base, like an alkoxide - EtONa=EtOH favors the more substituted double bond
    [Show full text]
  • Reactions of Alkenes and Alkynes
    05 Reactions of Alkenes and Alkynes Polyethylene is the most widely used plastic, making up items such as packing foam, plastic bottles, and plastic utensils (top: © Jon Larson/iStockphoto; middle: GNL Media/Digital Vision/Getty Images, Inc.; bottom: © Lakhesis/iStockphoto). Inset: A model of ethylene. KEY QUESTIONS 5.1 What Are the Characteristic Reactions of Alkenes? 5.8 How Can Alkynes Be Reduced to Alkenes and 5.2 What Is a Reaction Mechanism? Alkanes? 5.3 What Are the Mechanisms of Electrophilic Additions HOW TO to Alkenes? 5.1 How to Draw Mechanisms 5.4 What Are Carbocation Rearrangements? 5.5 What Is Hydroboration–Oxidation of an Alkene? CHEMICAL CONNECTIONS 5.6 How Can an Alkene Be Reduced to an Alkane? 5A Catalytic Cracking and the Importance of Alkenes 5.7 How Can an Acetylide Anion Be Used to Create a New Carbon–Carbon Bond? IN THIS CHAPTER, we begin our systematic study of organic reactions and their mecha- nisms. Reaction mechanisms are step-by-step descriptions of how reactions proceed and are one of the most important unifying concepts in organic chemistry. We use the reactions of alkenes as the vehicle to introduce this concept. 129 130 CHAPTER 5 Reactions of Alkenes and Alkynes 5.1 What Are the Characteristic Reactions of Alkenes? The most characteristic reaction of alkenes is addition to the carbon–carbon double bond in such a way that the pi bond is broken and, in its place, sigma bonds are formed to two new atoms or groups of atoms. Several examples of reactions at the carbon–carbon double bond are shown in Table 5.1, along with the descriptive name(s) associated with each.
    [Show full text]
  • Alkynes: Molecular and Structural Formulas
    Alkynes: Molecular and Structural Formulas The alkynes comprise a series of carbon- and hydrogen-based compounds that contain at least one triple bond. This group of compounds is a homologous series with the general molecular formula of C n H2 n--2 , where n equals any integer greater than one. The simplest alkyne, ethyne (also known as acetylene), has two carbon atoms and the molecular formula of C2H2. The structural formula for ethyne is In longer alkyne chains, the additional carbon atoms are attached to each other by single covalent bonds. Each carbon atom is also attached to sufficient hydrogen atoms to produce a total of four single covalent bonds about itself. In alkynes of four or more carbon atoms, the triple bond can be located in different positions along the chain, leading to the formation of structural isomers. For example, the alkyne of molecular formula C4H6 has two isomers, Although alkynes possess restricted rotation due to the triple bond, they do not have stereoisomers like the alkenes because the bonding in a carbon-carbon triple bond is sp hybridized. In sp hybridization, the maximum separation between the hybridized orbitals is 180°, so the molecule is linear. Thus, the substituents on triple-bonded carbons are positioned in a straight line, and stereoisomers are impossible Alkynes: Nomenclature Although some common alkyne names, such as acetylene, are still found in many textbooks, the International Union of Pure and Applied Chemistry (IUPAC) nomenclature is required for journal articles. The rules for alkynes in this system are identical with those for alkenes, except for the ending.
    [Show full text]
  • Gas Phase Synthesis of Interstellar Cumulenes. Mass Spectrometric and Theoretical Studies."
    rl ì 6. .B,1l thesis titled: "Gas Phase Synthesis of Interstellar Cumulenes. Mass Spectrometric and Theoretical studies." submitted for the Degree of Doctor of Philosophy (Ph.D') by Stephen J. Blanksby B.Sc.(Hons,) from the Department of ChemistrY The University of Adelaide Cì UCE April 1999 Preface Contents Title page (i) Contents (ii) Abstract (v) Statement of OriginalitY (vi) Acknowledgments (vii) List of Figures (ix) Phase" I Chapter 1. "The Generation and Characterisation of Ions in the Gas 1.I Abstract I 1.II Generating ions 2 t0 l.ru The Mass SPectrometer t2 1.IV Characterisation of Ions 1.V Fragmentation Behaviour 22 Chapter 2 "Theoretical Methods for the Determination of Structure and 26 Energetics" 26 2,7 Abstract 27 2.IT Molecular Orbital Theory JJ 2.TII Density Functional Theory 2.rv Calculation of Molecular Properties 34 2.V Unimolecular Reactions 35 Chapter 3 "Interstellar and Circumstellar Cumulenes. Mass Spectrometric and 38 Related Studies" 3.I Abstract 38 3.II Interstellar Cumulenes 39 3.III Generation of Interstellar Cumulenes by Mass Spectrometry 46 3.IV Summary 59 Preface Chapter 4 "Generation of Two Isomers of C5H from the Corresponding Anions' 61 ATheoreticallyMotivatedMassSpectrometricStudy.'. 6l 4.r Abstract 62 4.rl Introduction 66 4.III Results and Discussion 83 4.IV Conclusions 84 4.V Experimental Section 89 4.VI Appendices 92 Chapter 5 "Gas Phase Syntheses of Three Isomeric CSHZ Radical Anions and Their Elusive Neutrals. A Joint Experimental and Theoretical Study." 92 5.I Abstract 93 5.II Introduction 95 5.ru Results and Discussion t12 5.IV Conclusions 113 5.V Experimental Section ttl 5.VI Appendices t20 Chapter 6 "Gas Phase Syntheses of Three Isomeric ClHz Radical Anions and Their Elusive Neutrals.
    [Show full text]
  • Formation of Highly Ordered Self-Assembled Monolayers of Alkynes on Au(111) Substrate
    Formation of Highly Ordered Self-Assembled Monolayers of Alkynes on Au(111) Substrate The Harvard community has made this article openly available. Please share how this access benefits you. Your story matters Citation Zaba, Tomasz, Agnieszka Noworolska, Carleen Morris Bowers, Benjamin Breiten, George M. Whitesides, and Piotr Cyganik. 2014. Formation of Highly Ordered Self-Assembled Monolayers of Alkynes on Au(111) Substrate. Journal of the American Chemical Society 136, no. 34: 11918–11921. doi:10.1021/ja506647p. Published Version doi:10.1021/ja506647p Citable link http://nrs.harvard.edu/urn-3:HUL.InstRepos:33490483 Terms of Use This article was downloaded from Harvard University’s DASH repository, and is made available under the terms and conditions applicable to Open Access Policy Articles, as set forth at http:// nrs.harvard.edu/urn-3:HUL.InstRepos:dash.current.terms-of- use#OAP Page 1 of 5 Journal of the American Chemical Society 1 2 3 4 5 6 7 Formation of Highly Ordered Self-Assembled Monolayers of 8 9 Alkynes on Au(111) Substrate 10 ‡ ‡ § § 11 Tomasz Zaba, Agnieszka Noworolska, Carleen Bowers, Benjamin Breiten, 12 § ‡ 13 George M. Whitesides and Piotr Cyganik* 14 ‡Smoluchowski Institute of Physics, Jagiellonian University, ul. Reymonta 4, 30-059 Krakow, Poland 15 § 16 Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, MA 02138, USA 17 18 19 Supporting Information Placeholder 20 21 ABSTRACT: Self-assembled monolayers (SAMs), prepared SAMs are sensitive to oxidation at an undefined point in their formation; that is, oxidation occurs either during or after SAM 22 by reaction of terminal n-DON\QHV +&Ł& &+ 2)nCH 3, n = 5, 7, 9, o formation (for example, by UHDFWLRQ RI WKH $X&Ł&5 ERQG ZLWK 23 and 11) with Au(111) at 60 C were characterized using scanning tunneling microscopy (STM), infra-red reflection absorption O2).
    [Show full text]
  • Gfsorganics & Fragrances
    Chemicals for Flavors GFSOrganics & Fragrances GFS offers a broad range of specialty organic chemicals Specialized chemistries we as building blocks and intermediates for the manufacture of offer include: flavors and fragrances. • Alkynes Over 5,500 materials, including 1,400 chemicals from natural sources, are used for flavor • Alkynols enhancements and aroma profiles. These aroma chemicals are integral components of • Olefins the continued growth within consumer products and packaged foods. The diversity of products can be attributed to the broad spectrum of organic compounds derived from • Unsaturated Acids esters, aldehydes, lactones, alcohols and several other functional groups. • Unsaturated Esters • DIPPN and other Products GFS Chemicals manufactures a wide range of organic intermediates that have been utilized in a multitude of personal care applications. For example, we support Why GFS? several market leading companies in the manufacture and supply of alkyne based aroma chemicals. • Specialized Chemistries • Tailored Specifications As such, we understand the demanding nature of this fast changing market and are fully • From Grams to Metric Tons equipped to overcome process challenges and manufacture the novel chemical products • Responsive Technical Staff that you need, when you need them. We offer flexible custom manufacturing services to produce high purity products with the assurance of quality and full confidentiality. • Uncompromised Product Quality Our state-of-the-art manufacturing facility, located in Columbus, OH is ISO 9001:2008 certified. As a U.S. based manufacturer we have a proven record of helping you take products from development to commercialization. Our technical sales experts are readily accessible to discuss your project needs and unique product specifications.
    [Show full text]
  • Cycloadditions for Rapid, Scalable Access to Alkynylated Polycyclic Aromatic Cite This: Chem
    Chemical Science EDGE ARTICLE View Article Online View Journal | View Issue Site-selective [2 + 2 + n] cycloadditions for rapid, scalable access to alkynylated polycyclic aromatic Cite this: Chem. Sci., 2020, 11,3028 hydrocarbons† All publication charges for this article have been paid for by the Royal Society of Chemistry Gavin R. Kiel, Harrison M. Bergman and T. Don Tilley * Polycyclic aromatic hydrocarbons (PAHs) are attractive synthetic building blocks for more complex conjugated nanocarbons, but their use for this purpose requires appreciable quantities of a PAH with reactive functional groups. Despite tremendous recent advances, most synthetic methods cannot satisfy these demands. Here we present a general and scalable [2 + 2 + n](n ¼ 1 or 2) cycloaddition strategy to access PAHs that are decorated with synthetically versatile alkynyl groups and its application to seven structurally diverse PAH ring systems (thirteen new alkynylated PAHs in total). The critical discovery is the site-selectivity of an Ir-catalyzed [2 + 2 + 2] cycloaddition, which preferentially cyclizes tethered diyne units with preservation of other (peripheral) alkynyl groups. The potential for generalization of the site- Creative Commons Attribution-NonCommercial 3.0 Unported Licence. selectivity to other [2 + 2 + n] reactions is demonstrated by identification of a Cp2Zr-mediated [2 + 2 + 1]/metallacycle transfer sequence for synthesis of an alkynylated, selenophene-annulated PAH. The new PAHs are excellent synthons for macrocyclic conjugated nanocarbons. As a proof of concept, four were subjected to alkyne metathesis catalysis to afford large, PAH-containing arylene ethylene macrocycles, which possess a range of cavity sizes reaching well into the nanometer regime. Notably, these high- Received 2nd December 2019 yielding macrocyclizations establish that synthetically convenient pentynyl groups can be effective for Accepted 15th February 2020 metathesis since the 4-octyne byproduct is sequestered by 5 A˚ MS.
    [Show full text]
  • Alkynes and Their Reactions Naming Alkynes • Alkynes Are Named in the Same General Way That Alkenes Are Named
    Alkynes and Their Reactions Naming Alkynes • Alkynes are named in the same general way that alkenes are named. • In the IUPAC system, change the –ane ending of the parent alkane name to the suffix –yne. • Choose the longest continuous chain that contains both atoms of the triple bond and number the chain to give the triple bond the lower number. • Compounds with two triple bonds are named as diynes, those with three are named as triynes and so forth. • Compounds with both a double and triple bond are named as enynes. • The chain is numbered to give the first site of unsaturation (either C=C or C≡C) the lower number. Chapter 11 Preparation of Alkynes Preparation of Alkynes from Alkenes • Alkynes are prepared by elimination reactions. • Since vicinal dihalides are readily made from alkenes, one can convert an alkene • A strong base removes two equivalents of HX from a vicinal to the corresponding alkyne in a or geminal dihalide to yield an alkyne through two successive E2 two-step process involving: elimination reactions. • Halogenation of an alkene. • Double dehydrohalogenation of the resulting vicinal dihalide. • IMPORTANT NOTE: Synthesis of a terminal alkyne by dehydrohalogenation requires 3 equivalents of the base, due to the acidity of the terminal alkyne H H Br 3 equiv. NaNH2 HX Br H2O Terminal Alkynes – Reaction as an Acid Reactions of Alkynide Ions with Alkyl Halides • Terminal alkynes are readily converted to alkynide (acetylide) ions with strong • Acetylide anions are strong nucleophiles and react with unhindered alkyl halides to bases such as NaNH2 and NaH. yield products of nucleophilic substitution.
    [Show full text]
  • Supplementary Information
    Electronic Supplementary Material (ESI) for ChemComm. This journal is © The Royal Society of Chemistry 2017 Supplementary Information N-Heterocycle Carbene Copper Catalyzed Direct Alkylation of Terminal Alkynes with Nonactivated Alkyl Triflates Liqun Jin,*ab Wangfang Hao,a Jianeng Xu,a Nan Sun,a Baoxiang Hu,a Zhenlu Shen,a Weimin Mo,a and Xinquan Hu*ab a College of Chemical Engineering, Zhejiang University of Technology, Hangzhou 310032, P.R. China b State Key Laboratory for Oxo Synthesis and Selective Oxidation Lanzhou Institute of Chemical Physics Chinese Academy of Sciences, Lanzhou 730000, P.R. China 1 Table of Contents 1. General 2. General procedure for Cu-catalyzed alkylations of terminal alkynes 3. Reaction optimization of NHC-Copper catalyzed coupling of phenylacetylene with octyl triflate 3. Mechanistic studies 4. Scale-up reactions 5. NMR spectra of copper complexes and coupling products 6. References 2 1. General All reactions were carried out under nitrogen atmosphere unless otherwise noted. All 1H and 13C NMR spectra were recorded on Bruker ADVANCE III 500 MHz spectrometer in deuterium solvents with tetramethylsilane (TMS) as internal standard. NMR multiplicities are abbreviated as follows: s = singlet, d = doublet, t = triplet, q = quartet, sept = septet, m = multiplet, br = broad signal. Chemical shifts are given in ppm and are referenced to TMS (1H, 13C). All spectra were obtained at 25 °C in the solvent indicated. Coupling constants J are given in Hz. GC analyses were performed on Agilent 6890 instrument with FID detector using an HP-5 capillary column (30 m x 0.32 mm (i.d.), 0.25 ). High-resolution mass spectra were recorded in the EI mode on Waters GCT Premier TOF MS.
    [Show full text]