DOCSLIB.ORG

Thesis Rests with Its Author

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Thesis Rests with Its Author University of Bath PHD Catalytic electronic activation: The addition of nucleophiles to an allylic alcohol Black, Phillip James Award date: 2002 Awarding institution: University of Bath Link to publication Alternative formats If you require this document in an alternative format, please contact: [email protected] General rights Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights. • Users may download and print one copy of any publication from the public portal for the purpose of private study or research. • You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal ? Take down policy If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim. Download date: 08. Oct. 2021 Catalytic Electronic Activation: The Addition of Nucleophiles to an Allylic Alcohol submitted by Phillip James Black for the degree of PhD of the University of Bath 2002 COPYRIGHT Attention is drawn to the fact that copyright of this thesis rests with its author. This copy of the thesis has been supplied on condition that anyone who consults it is understood to recognise that its copyright rests with its author and that no quotation from the thesis and no information derived from it may be published without the prior written consent of the author. This thesis may be made available for consultation with the University Library and may be photocopied or lent to other libraries for the purposes of consultation. /g Ae.c Z-ovz^ UMI Number: U601493 All rights reserved INFORMATION TO ALL USERS The quality of this reproduction is dependent upon the quality of the copy submitted. In the unlikely event that the author did not send a complete manuscript and there are missing pages, these will be noted. Also, if material had to be removed, a note will indicate the deletion. Dissertation Publishing UMI U601493 Published by ProQuest LLC 2013. Copyright in the Dissertation held by the Author. Microform Edition © ProQuest LLC. All rights reserved. This work is protected against unauthorized copying under Title 17, United States Code. ProQuest LLC 789 East Eisenhower Parkway P.O. Box 1346 Ann Arbor, Ml 48106-1346 e i o e i Contents Contents Page No. Contents i Acknowledgements iii Abstract iv Abbreviations v Chapter 1.0 Introduction 1.1 Sequential reactions 1 1.2 Oxidation and Reduction reactions 5 1.3 The Oppenauer Oxidation and 9 Meerwein-Ponndorf-Verley reduction 1.4 Modified Aluminium MPVO catalysts 13 1.5 Lanthanide catalysed MPVO reactions 28 1.6 Zirconium and Hafnium catalysed MPVO Chemistry 33 1.7 Miscellaneous MPVO reactions 37 1.8 Heterogeneous MPVO catalysts 43 1.9 Meerwein-Ponndorf-Verley Alkylation 44 1.10 References 46 Chapter 2.0 Results and Discussion I 2.1 Project Overview 52 2.2 Preparation of Starting Materials and Control Studies 58 2.3 Oxidation and Reduction Reactions 61 2.4 Catalytic Oppenauer oxidations/ MPV Reductions 64 2.5 Aluminium tert-butoxide catalysed MPVO reactions 71 2.6 Dimethylaluminium chloride catalysed MPVO Reactions 76 2.6 References 79 Chapter 3.0 Results and Discussion II 3.1 Towards the addition of Methyl Malononitrile to an Allylic Alcohol 81 3.2 Cyclopentyl domino Oppenauer/Michael addition/MPV process 91 3.3 Towards the addition of Methyl Malononitrile to Linear 99 Allylic Alcohols 3.4 References 108 Contents Chapter 4.0 Appendices 4.1 Transition Metal Catalysed Oxidation and Reduction Reactions 110 4.2 Miscellaneous Michael Addition Reactions 113 4.3 Towards the addition of ferf-Butylcyanoacetate to an Allylic Alcohol 116 4.4 X-Ray data: trans-2-Benzyl-2-(3-hydroxy-cyclohexyl)- 118 malononitrile; trans-171 4.5 trans-2-benzyl-2-(3-oxo-cyclopentyl)-malononitrile; trans-180 124 4.6 para-Nitro-benzoic acid 3-(dicyano-methyl-methyl)- 130 cyclopentyl ester; trans-177 4.7 cis-2-(3-Hydroxy-cyclohexyl)-2-methyl-malononitrile; cis-168 137 4.8 References 142 Chapter 5.0 Experimental 5.1 General Experimental 145 5.2 Experimental Procedures: Chapter 2 Experimental 147 5.3 Experimental Procedures: Chapter 3 Experimental 162 5.4 Experimental Procedures: Appendices Experimental 187 5.5 References 192 Acknowledgements Acknowledgements I would like to thank many people for the part they played in helping me to complete this PhD. All the people in my lab, especially (the now absent) Kerry, have given me a lot of their time in order to sort out the (numerous) problems I have encountered. My supervisor Jon has spent many hours going through the project with me and has come up with most of the better ideas. For social reasons, I should mention the all-conquering ChemAdmin football team and in particular Joe Hartley for honing my pool skills. And finally I would like to thank Mike Edwards and Inga who have helped me more than anybody. I thank you all. The work described in this Thesis is entirely my own, except where I have acknowledged either help from a named person or a reference is given to a published source or Thesis. Text taken from another source will be enclosed in quotation marks and a reference will be given. Date: Signature: Abstract Abstract This report describes a number of methods to activate 2-cyclohexen-1-ol 112 and 2- cyclopenten-1-ol 173 through the use of aluminium-catalysed transfer hydrogentation. The electronically activated substrates are demonstrated to undergo facile conjugate addition and, when the alcohol functional group is subsequently restored in a one-pot procedure this leads to an indirect addition of nucleophiles to allylic alcohols. This novel methodology has been termed Catalytic Electronic Activation (CEA). The aluminium te/f-butoxide catalysed conversion of 2-cyclohexen-1-ol 112 into 2-(3- hydroxy-cyclohexyl)-2-methyl-malononitrile 168 and 2-cyclopenten-1-ol 173 into 2-(3- Hydroxy-cyclopentyl)-2-methyl-malononitrile 175 in 90% and 60% yield respectively has been demonstrated through an efficient domino Oppenauer/Michael addition/MPV process. Abbreviations Abbreviations Ac Acetyl acac Acetylacetonate Ar Unspecified aryl group ax Axial Bl NOL 1,1 ’-Bi-2-napthol Bn Benzyl BnBr Benzyl bromide b.p. Boiling point Bu Butyl CEA Catalytic Electronic Activation COD 1,5-Cyclooctadiene Da Daltons DABCO 1,4-Diazabicyclo[2.2.2]octane DBU 1,8-diazabicyclo[5.4.0]undec-7- ene de Diastereomeric excess DIBAL Diisobutylaluminium hydride DMAP 4-A/,A/-Dimethylaminopyridine DMF /V,/V-Dimethylformamide DMSO Dimethylsulfoxide DPAT Diphenylammonium triflate EDBP 2,2-ethylidenebis(4,6-di-te/f- butylphenol) EDC 1-(3-dimethylaminopropyl)-3- ethylcarbodiimide hydrochloride ee Enantiomeric excess El Electron Impact eq Equatorial Et Ethyl h Hour HPLC High Performance Liquid Chromatography HRMS High resolution mass spectrometry Hz Hertz Abbreviations i iso /PA isopropanol /Pr /so-Propyl FT-IR Fourier Transform Infra-red J Coupling constant LHMDS Lithium hexamethyldisilazide M Molar Me Methyl MeOH Methanol MeCN Acetonitrile MMPEP 2f2,-methylenebis(4,6-di(1 - methyl-1 -phenylethyl)phenol MPV Meerwein-Ponndorf-Verley MPVO Meerwein-Ponndorf-Verley- Oppenauer MS Mass Spectrometry n normal N Moles per litre NMR Nuclear Magnetic Resonance Nuc Unspecified nucleophile p para Ph Phenyl ppm Parts per million Pr Propyl Py Pyridine R Unspecified alkyl group RT Room temperature s sec SET Single Electron Transfer t tert ©u tert-butyl TBAB Tri-butylammonium bromide TFA Trifluoroacetic acid THF Tetrahydrofuran TLC Thin layer chromatography TMSCI tri-Methylsilychloride TPP 5,10,15,20-tetraphenylporphinato C H » P t e f 1 Chapter 1 Introduction 1.1 Sequential Reactions In the early days of organic synthesis only simple molecules were prepared. In the meantime, the complexity of target molecules has increased considerably. The current pinnacle has been reached with the synthesis of palytoxin with sixty four- stereogenic centres,1 of which, in principal, over 1019 stereogenic forms can exist. For this reason it has been necessary to develop chemical transformations with increasingly higher selectivity. Thus, in the past few years a wealth of chemo-, regio-, diastereo-, and enantioselective reactions have been discovered and developed, the selectivity of which frequently approaches that of enzymatic processes. Nevertheless, if we compare our synthetic performance to date with that of Nature, then we must recognise that Nature is not just highly selective, but also very efficient, often employing sequential transformations. By this we understand a series of reaction steps in which several bonds are formed or broken, without the isolation of any intermediates. A particularly fascinating example from Nature is the cyclisation of squalene oxide 1 (Scheme 1) to give lanosterol 2, a starting material for many steroids.2 Me Me Me Me Me Me Me Me HO Me Me Me 2 Scheme 1 Cyclisation of squalene oxide Sequential reactions are characterised by their great elegance, frequently high stereoselectivity and by the simple manner in which they may be carried out. Moreover, the development of this type of synthetic method can lead to a reduction in the amount of undesired by-products, thereby contributing to the protection of the environment. For example, the quantity of solvents and eluents required in l Chapter 1 Introduction
Load more

Recommended publications
  • The Organic Chemistry of Drug Synthesis
    The Organic Chemistry of Drug Synthesis VOLUME 2 DANIEL LEDNICER Mead Johnson and Company Evansville, Indiana LESTER A. MITSCHER The University of Kansas School of Pharmacy Department of Medicinal Chemistry Lawrence, Kansas A WILEY-INTERSCIENCE PUBLICATION JOHN WILEY AND SONS, New York • Chichester • Brisbane • Toronto Copyright © 1980 by John Wiley & Sons, Inc. All rights reserved. Published simultaneously in Canada. Reproduction or translation of any part of this work beyond that permitted by Sections 107 or 108 of the 1976 United States Copyright Act without the permission of the copyright owner is unlawful. Requests for permission or further information should be addressed to the Permissions Department, John Wiley & Sons, Inc. Library of Congress Cataloging in Publication Data: Lednicer, Daniel, 1929- The organic chemistry of drug synthesis. "A Wiley-lnterscience publication." 1. Chemistry, Medical and pharmaceutical. 2. Drugs. 3. Chemistry, Organic. I. Mitscher, Lester A., joint author. II. Title. RS421 .L423 615M 91 76-28387 ISBN 0-471-04392-3 Printed in the United States of America 10 987654321 It is our pleasure again to dedicate a book to our helpmeets: Beryle and Betty. "Has it ever occurred to you that medicinal chemists are just like compulsive gamblers: the next compound will be the real winner." R. L. Clark at the 16th National Medicinal Chemistry Symposium, June, 1978. vii Preface The reception accorded "Organic Chemistry of Drug Synthesis11 seems to us to indicate widespread interest in the organic chemistry involved in the search for new pharmaceutical agents. We are only too aware of the fact that the book deals with a limited segment of the field; the earlier volume cannot be considered either comprehensive or completely up to date.
    [Show full text]
  • Transfer Hydrogenations and Kinetic Resolutions Van Dirk Klomp
    transferhydrogenations and kineticresolutions DirkKlomp transferhydrogenationsandkineticresolutions DirkKlomp Uitnodiging voorhetbijwonenvande openbareverdedigingvan hetproefschriften destellingenop maandag 13maart2006 13.00uur endedaaraan voorafgaandetoelichting voorniet-chemiciom 12.30uur indeSenaatszaalvande TechnischeUniversiteitDelft Mekelweg5teDelft Naafloopvande plechtigheidbentuookvan hartewelkomopdereceptie inhetzelfdegebouw. DirkKlomp Esdoornlaan32 1521EBWormerveer 075-6223403 [email protected] Stellingen behorende bij het proefschrift transfer hydrogenations and kinetic resolutions van Dirk Klomp 1- De door Kao et al. gebruikte structuurbepalende verbinding fructose voor de synthese van de mesoporeuze silica SBA-1 bepaalt niet de structuur van het materiaal. H.-M. Kao, C.-C. Ting, A. S. T. Chiang, C.-C. Teng, C.-H. Chen, Chem. Commun. 2005 ,1058-1060. 2- Het door Kim et al. gesuggereerde mechanisme voor de deactivering van het enzym α-CT in de hydrolyse van β-lactonen, waarbij het lacton opent op de 4-positie, is zeer onwaarschijnlijk. D. H. Kim, J. Park, S. J. Chung, J. D. Park, N.-K. Park, J. H. Han, Bioorg. Med. Chem. 2002 , 10 , 2553-2560. 3- Psychologisch gezien betekent de omschakeling door wetenschappelijke tijdschriften van papieren versies naar elektronische, een verlies aan kennis voor de wetenschapper. 4- Omdat de aarde langzamer gaat draaien is soms de toevoeging van schrikkelsecondes noodzakelijk. Wetenschappers die deze secondes pas willen toevoegen op het moment dat ze zijn opgespaard tot een schrikkeluur, omdat de toevoegingen storingen kunnen veroorzaken in elektronische apparatuur, hebben de menselijke factor uit het oog verloren. 5- In de weekeindes waarin een nieuw boek over Harry Potter uitkomt, is het aantal kinderen dat op de eerstehulpafdeling van het ziekenhuis belandt bijna half zo groot als in andere weekeindes. Gwilym et al. hebben de afname over de lange termijn waarschijnlijk onderschat.
    [Show full text]
  • Synthesis, Hydrogenation, and Hydrodeoxygenation of Biomass-Derived Furans for Diesel Fuel
    Synthesis, Hydrogenation, and Hydrodeoxygenation of Biomass-Derived Furans for Diesel Fuel By Ying Lin Louie A dissertation submitted in partial satisfaction of the requirements for the degree of Doctor of Philosophy in Chemical Engineering in the Graduate Division of the University of California, Berkeley Committee in charge: Professor Alexis T. Bell, Chair Professor Alexander Katz Professor F. Dean Toste Summer 2017 Synthesis, Hydrogenation, and Hydrodeoxygenation of Biomass-Derived Furans for Diesel Fuel © 2017 Ying Lin Louie All rights reserved Abstract Synthesis, Hydrogenation, and Hydrodeoxygenation of Biomass-Derived Furans for Diesel Fuel by Ying Lin Louie Doctor of Philosophy in Chemical Engineering University of California, Berkeley Professor Alexis T. Bell, Chair Hydrogenation and hydrodeoxygenation (HDO) processes are critical for the chemical conversion of lignocellulosic biomass into liquid transportation fuels such as gasoline, jet, and diesel. Hydro-treatment processes can remove undesired functionalities and reduce the oxygen content in biomass-derived oxygenates to produce candidates suitable for fuel blends. In this study, the liquid phase hydrogenation and hydrogenolysis of several model substrates including, 2,5-dimethylfuran (DMF), 5-methylfurfural (5-MF), bis(5-methylfuran-2-yl)methane (BMFM), and 5-(2-(5-methylfuran-2-yl)vinyl)furan-2-aldehyde (MFVFAL), were investigated over noble metal catalysts (Pd, Pt, Ru) at moderate conditions (353 – 473 K, 0.55 – 5.1 MPa). Understanding the mechanism and kinetics by which undesired functionalities found in these substrates, such as aromatic furans, unsaturated C=C bonds, and C=O bonds, are removed during hydrogenation will allow for the design of efficient catalysts and processes to improve the hydroupgrading reactions of biomass-derived fuels.
    [Show full text]
  • The Evans-Tishchenko Reaction: Scope and Applications
    Edinburgh Research Explorer The Evans-Tishchenko Reaction: Scope and Applications Citation for published version: Ralston, KJ & Hulme, AN 2012, 'The Evans-Tishchenko Reaction: Scope and Applications', Synthesis: Journal of Synthetic Organic Chemistry, vol. 44, no. 15, SS-2012-M0312-SR, pp. 2310–2324. https://doi.org/10.1055/s-0032-1316544 Digital Object Identifier (DOI): 10.1055/s-0032-1316544 Link: Link to publication record in Edinburgh Research Explorer Document Version: Peer reviewed version Published In: Synthesis: Journal of Synthetic Organic Chemistry Publisher Rights Statement: Copyright © 2012 Georg Thieme Verlag Stuttgart & New York. All rights reserved. General rights Copyright for the publications made accessible via the Edinburgh Research Explorer is retained by the author(s) and / or other copyright owners and it is a condition of accessing these publications that users recognise and abide by the legal requirements associated with these rights. Take down policy The University of Edinburgh has made every reasonable effort to ensure that Edinburgh Research Explorer content complies with UK legislation. If you believe that the public display of this file breaches copyright please contact [email protected] providing details, and we will remove access to the work immediately and investigate your claim. Download date: 07. Oct. 2021 This document is the Accepted Version of a published article that appeared in final form in Synthesis, copyright © Georg Thieme Verlag Stuttgart · New York. To access the final edited and published work see http://dx.doi.org/10.1055/s-0032-1316544 Cite as: Ralston, K. J., & Hulme, A. N. (2012). The Evans-Tishchenko Reaction: Scope and Applications.
    [Show full text]
  • THE STEREOCHEMISTRY of the CATALYTIC HYDROGENATION of Compounds Containing an a S M E T R Ic CARBON ATOM
    THE STEREOCHEMISTRY OF THE CATALYTIC HYDROGENATION of compounds containing an a s m e t r ic CARBON ATOM By TERENCE JOHN HOWARD A T hesis submitted to the University of London for the Degree of Doctor of Philosophy in th e Faculty of Science The Organic Research Laboratories, Battersea College of Technology, Sept. i 960 London, S.W .ll. ProQuest Number: 10804653 All rights reserved INFORMATION TO ALL USERS The quality of this reproduction is dependent upon the quality of the copy submitted. In the unlikely event that the author did not send a complete manuscript and there are missing pages, these will be noted. Also, if material had to be removed, a note will indicate the deletion. uest ProQuest 10804653 Published by ProQuest LLC(2018). Copyright of the Dissertation is held by the Author. All rights reserved. This work is protected against unauthorized copying under Title 17, United States Code Microform Edition © ProQuest LLC. ProQuest LLC. 789 East Eisenhower Parkway P.O. Box 1346 Ann Arbor, Ml 4 8 1 0 6 - 1346 2 ABSTRACT OF THESIS 4-Phenyl pen t-3-en-2--one has been prepared by the reaction of dimethyl cadmium with j3~methylcinnamoyl chloride, and its structure confirmed by a haloform degradation to trans - Q - methylcinnamic acid. Reduction of the ketone with aluminium isopropoxide gave (i)-4“Pbenylpent-3-en~2~ol, characterised by the preparation of the 3J-a-naphthyl and R-4-diphenylyl-carbamates. On catalytic hydrogenation (-)-4“-phenylpent-3-en-2--ol gave a mixture of the two diastereoisomeric racemates of (-)~4~phenylpentan-2-ol in which a new centre of asymmetry has been generated at C^.
    [Show full text]
  • Organic Chemistry Reactions
    Organic Chemistry Reactions 1 Birch Reduction Birch Reduction The Birch Reduction offers access to substituted 1,4-cyclohexadienes. Mechanism of Birch Reduction I) The question of why the 1,3-diene is not formed, even though it would be more stable through conjugation, can be rationalized with a simple mnemonic. When viewed in valence bond terms, electron-electron repulsions in the radical anion will preferentially have the nonbonding electrons separated as much as possible, in a 1,4-relationship This question can also be answered by considering the mesomeric structures of the dienyl carbanion: II) The numbers, which stand for the number of bonds, can be averaged and compared with the 1,3- and the 1,4-diene. The structure on the left is the average of all mesomers depicted above followed by 1,3 and 1,4-diene: III) The difference between the dienyl carbanion and 1,3-diene in absolute numbers is 2, and between the dienyl carbanion and 1,4-diene is 4/3. The comparison with the least change in electron distribution will be preferred. Reactions of arenes with +I- and +M-substituents lead to the products with the most highly substituted double bonds: IV) The effect of electron-withdrawing substituents on the Birch Reduction varies. For , the reaction of benzoic acid leads to 2,5- cyclohexadienecarboxylic acid, which can be rationalized on the basis of the carboxylic acid stabilizing an adjacent anion: V) Alkene double bonds are only reduced if they are conjugated with the arene, and occasionally isolated terminal alkenes will be reduced. 2 Aldol Condensation Aldol Condensation In some cases, the adducts obtained from the Aldol Addition can easily be converted (in situ) to ,-unsaturated carbonyl compounds, either thermally or under acidic or basic catalysis.
    [Show full text]
  • Regioselective Biocatalytic Self-Sufficient Tishchenko-Type
    ChemComm View Article Online COMMUNICATION View Journal | View Issue Regioselective biocatalytic self-sufficient Tishchenko-type reaction via formal Cite this: Chem. Commun., 2020, 56,6340 intramolecular hydride transfer† Received 9th April 2020, a a a a Accepted 28th April 2020 Erika Tassano, Kemal Merusic, Isa Buljubasic, Olivia Laggner, a b a Tamara Reiter, Andreas Vogel and Me´lanie Hall * DOI: 10.1039/d0cc02509g rsc.li/chemcomm A self-sufficient nicotinamide-dependent intramolecular bio-Tishchenko- Recently, we established a biocatalytic variant of the (inter- type reaction was developed. The reaction is catalyzed by alcohol molecular) Cannizzaro reaction, which could be further developed dehydrogenases and proceeds through formal intramolecular into a parallel interconnected dynamic asymmetric disproportio- hydride transfer on dialdehydes to deliver lactones. Regioselectivity nation of a-substituted aldehydes. The system relies on the con- 0 0 Creative Commons Attribution-NonCommercial 3.0 Unported Licence. on [1,1 -biphenyl]-2,2 -dicarbaldehyde substrates could be controlled current oxidative and reductive activity of nicotinamide-dependent via the electronic properties of the substituents. Preparative scale alcohol dehydrogenases (ADHs) to perform the dismutation of synthesis provided access to substituted dibenzo[c,e]oxepin-5(7H)-ones. aldehydes with high enantioselectivity in a redox-neutral fashion.11,12 The latter feature renders the system appealing from a sustainability The Claisen–Tishchenko reaction is a disproportionation reaction pointofview,sinceonlycatalyticamounts of cofactor are necessary, that leads to the formation of esters through dimerization of in addition to the biocatalyst. Since two products are generated, an aldehydes.1 Due to the variety of protocols available, it is a additional purification step is necessary, or alternatively, convergent synthetically relevant transformation2 and one of the major processes toward a single product must be designed.
    [Show full text]
  • Total Syntheses and Synthetic Studies of Spongiane Diterpenes
    Available online at www.sciencedirect.com Tetrahedron 64 (2008) 445e467 www.elsevier.com/locate/tet Tetrahedron report number 821 Total syntheses and synthetic studies of spongiane diterpenes Miguel A. Gonza´lez* Departamento de Quı´mica Orga´nica, Universidad de Valencia, E-46100 Burjassot, Valencia, Spain Received 2 October 2007 Available online 22 October 2007 Keywords: Diterpenes; Spongiane; Marine natural products; Synthesis Contents 1. Introduction ................................................................................................................. 445 2. Structure, occurrence, and biological activity ................................................................................ 446 3. Syntheses of spongiane diterpenes ........................................................................................... 446 3.1. Syntheses from other natural products ............................................................................... 446 3.2. Syntheses by biomimetic approaches ................................................................................. 456 3.3. Other approaches and total syntheses ................................................................................ 459 4. Conclusions .................................................................................................................. 465 Acknowledgements .......................................................................................................... 465 References and notes .......................................................................................................
    [Show full text]
  • Chemistry Topic: Aldehyde Ketones and Carboxylic Acid No
    Class: 12 Subject: chemistry Topic: Aldehyde ketones and carboxylic acid No. of Questions: 25 1. Directions: The following question has four choices out of which ONLY ONE is correct. The Cannizzaro reaction is not given by: a. trimethylacetaldehyde b. acetaldehyde c. benzaldehyde d. formaldehyde Sol.(b)For aldehydes with a hydrogen atom alpha to the carbonyl, i.e. R2CHCHO, the preferred reaction is an aldol condensation, originating from deprotonation of this hydrogen. This reaction restricts the scope of the Cannizzaro reaction. 2. Benzene reacts with CH3COCl in the presence of anhydrous AlCl3 to give a. C6H5CH3 b. C6H5Cl c. C6H5O2Cl askIITians d. C6H5COCH3 Sol.(d)Benzene reacts with CH3COCl in the presence of anhydrous AlCl3 to give C6H5COCH3. 3. Benzaldehyde reacts with ammonia to form a. benzaldehyde ammonia b. hydrobenzamide c. urotropine d. ammonium chloride Sol.(b)Benzaldehyde reacts with ammonia to form hydrobenzamide 4. Formaldehyde on reaction with ammonia forms urotropine whose formula is a. (CH2)6 N4 b. (CH2)4 N6 c. (CH2)3 N4 d. (CH3)6 N4 Sol.(a)Formaldehyde on reaction with ammonia forms urotropine whose formula is (CH2)6 N4. 5. What is the increasing order of the rate of HCN addition to compounds A – D? A. HCHO B. CH3COCH3 C. PhCOCH3 D. PhCOPh askIITians a. C < D < B < A b. A < B < C < D c. D < B < C < A d. D < C < B < A Sol.(d)reater is the positivity of carbon in carbonyl group, higher is the reactivity towards nucleophilic addition (i.e HCN addition) 6. Under Wolf-Kishner reduction conditions, the conversion which may be brought about is a.
    [Show full text]
  • Tishchenko Reaction
    Tishchenko reaction The Tishchenko reaction is an organic chemical reaction that involves disproportionation of an aldehyde in the presence of an alkoxide. The reaction is named after Russian organic chemist Vyacheslav Tishchenko, who discovered that aluminium alkoxides are effective catalysts for the reaction.[1][2] [3] In the related Cannizzaro reaction, the base is sodium hydroxide and then the oxidation product is a carboxylic acid and the reduction product is an alcohol. Contents History Examples Further reading Related topics References History The reaction involving benzaldehyde was discovered by Claisen using sodium benzylate as base.[1] The reaction produces benzyl benzoate.[4] Enolizable aldehydes are not amenable to Claisen's conditions. Vyacheslav Tishchenko discovered that aluminium alkoxides allowed the conversion of enolizable aldehydes to esters. Examples The Tishchenko reaction of acetaldehyde gives the commercially important solvent ethyl acetate. The reaction is catalyzed by aluminium alkoxides.[5] The Tishchenko reaction is used to obtain isobutyl isobutyrate, a specialty solvent.[6] Hydroxypivalic acid neopentyl glycol ester is produced by a Tishchenko reaction from hydroxypivaldehyde in the presence of a basic catalyst (e.g., aluminium oxide).[7] The Tishchenko reaction of paraformaldehyde in the presence of aluminum methylate or magnesium methylate forms methyl formate.[8] Paraformaldehyde reacts with boric acid to form methyl formate.[9] The key step in the reaction mechanism for this reaction is a 1,3-hydride shift in the hemiacetal intermediate formed from two successive nucleophilic addition reactions, the first one from the catalyst. The hydride shift regenerates the alkoxide catalyst. Further reading V. E. Tishchenko | title= О действии алкоголятов алюминия на альдегиды.
    [Show full text]
  • Cis-Trans Enantiomerism, Fulvene Cycloadditions And
    View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by Electronic Theses and Dissertations at Indian Institute of Science SYNOPSIS ‘Topics in Synthetic Methodology: from Heterocycles to Hydride Transfers’ This thesis, largely describing diverse studies in organic synthesis, is divided into three parts. Part I, titled ‘Heterocycles’, describes in two chapters studies directed towards elaborating certain thiazole and oxazole derivatives as useful synthons. Part II, titled ‘Hydride transfers’, describes in two chapters synthetic and some mechanistic studies involving the Cannizzaro and Tishchenko reactions, apart from work with chirally-modified alumino and borohydride reagents. Finally, Part III, titled ‘Miscellaneous studies’, describes structural studies on cyclic carbonates. PART I. HETEROCYCLES O O S O DCC, 10min. (i) (ii) R OH S S Ph N N S H DCM, rt N N O Ph Ph Ph 1 I 2 (68-81%) (i) 5 mol % Pb(OAc)2Ph(OH)2 (ii) RCHO, DCM, rt, 20min. R = Et, n-Pr, i-Pr, i-Bu, n-Hexyl, Ph, PhCH=CH-, 4-MeO-C6H4- Scheme I Chapter 1. The Erlenmeyer synthesis with a thioazlactone and its applications. This chapter describes the synthesis and reactivity of 2-phenylthiazolin-5-one (1). This was generated in situ from N-(thiobenzoyl)glycine and N,N’-dicyclohexylcarbodiimide in CH2Cl2/r.t., and condensed with various aldehydes (Scheme I). The reaction occurred rapidly at room temperatures to furnish the corresponding 4-alkylidene or arylidene products (2) in excellent yields (68-81%). i The reaction was catalysed by basic lead acetate, and was equally successful with both aliphatic and aromatic aldehydes.
    [Show full text]
  • The Winding Road from Oppenauer to Sustainable Catalytic Oxidations of Alcohols
    The winding road from Oppenauer to sustainable catalytic oxidations of alcohols Citation for published version (APA): Meijer, R. H. (2002). The winding road from Oppenauer to sustainable catalytic oxidations of alcohols. Technische Universiteit Eindhoven. https://doi.org/10.6100/IR557870 DOI: 10.6100/IR557870 Document status and date: Published: 01/01/2002 Document Version: Publisher’s PDF, also known as Version of Record (includes final page, issue and volume numbers) Please check the document version of this publication: • A submitted manuscript is the version of the article upon submission and before peer-review. There can be important differences between the submitted version and the official published version of record. People interested in the research are advised to contact the author for the final version of the publication, or visit the DOI to the publisher's website. • The final author version and the galley proof are versions of the publication after peer review. • The final published version features the final layout of the paper including the volume, issue and page numbers. Link to publication General rights Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights. • Users may download and print one copy of any publication from the public portal for the purpose of private study or research. • You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal.
    [Show full text]