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246 x 189 17mm GREEN BOX RULES ARE FOR PROOF STAGE ONLY. DELETE BEFORE FINAL PRINTING. P a r s Andrew F. Parsons o n s K E Y N O T E S I N Organic Chemistry K E Y N O T E S I N S E C O N D E D I T I O N Organic K Andrew F. Parsons Department of Chemistry, University of York, UK E Y N O This concise and accessible textbook provides notes for students studying chemistry and related courses T Chemistry E at undergraduate level, covering core organic chemistry in a format ideal for learning and rapid revision. S The material, with an emphasis on pictorial presentation, is organised to provide an overview of the I N essentials of functional group chemistry and reactivity, leading the student to a solid understanding of O the basics of organic chemistry. r g This revised and updated second edition of Keynotes in Organic Chemistry includes: a S E C O N D E D I T I O N (cid:129) new margin notes to emphasise links between different topics, n i (cid:129) colour diagrams to clarify aspects of reaction mechanisms and illustrate key points, and c C (cid:129) a new keyword glossary. h e In addition, the structured presentation provides an invaluable framework to facilitate the rapid learning, m understanding and recall of critical concepts, facts and definitions. Worked examples and questions are i s included at the end of each chapter to test the reader’s understanding. t r y Reviews of the First Edition “ …this text provides an outline of what should be known and understood, including fundamental concepts and mechanisms.” S E Journal of Chemical Education, 2004 C O “ Despite the book’s small size, each chapter is thorough, with coverage of all important N reactions found at first-year level... ideal for the first-year student wishing to revise… D and priced and designed appropriately.” E D The Times Higher Education Supplement, 2004 I T I O N Keynotes in Organic Chemistry Keynotes in Organic Chemistry Second Edition ANDREWF.PARSONS DepartmentofChemistry,UniversityofYork,UK Thi s edition first published 2014 # 2014 John Wiley & Sons, Ltd Registered office John Wiley & Sons Ltd, The Atrium, Southern Gate, Chichester, West Sussex, PO19 8SQ, United Kingdom For de tails of our global editorial offices, for cu stomer services and for information about how to apply for perm ission to reuse the copyright m aterial in this book please see our website at www.wiley.com. Therightoftheauthortobeidentifiedastheauthorofthisworkhasbeenassertedinaccordancewiththe Copyright,DesignsandPatentsAct1988. Allrightsreserved.Nopartofthispublicationmaybereproduced,storedinaretrievalsystem,or transmitted,inanyformorbyanymeans,electronic,mechanical,photocopying,recordingorotherwise, exceptaspermittedbytheUKCopyright,DesignsandPatentsAct1988,withoutthepriorpermissionofthe publisher. Wileyalsopublishesitsbooksinavarietyofelectronicformats.Somecontentthatappearsinprintmaynot beavailableinelectronicbooks. Designationsusedbycompaniestodistinguishtheirproductsareoftenclaimedastrademarks.Allbrand namesandproductnamesusedinthisbookaretradenames,servicemarks,trademarksorregistered trademarksoftheirrespectiveowners.Thepublisherisnotassociatedwithanyproductorvendormentioned inthisbook. 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LibraryofCongressCataloging-in-PublicationData Parsons,A.F. Keynotesinorganicchemistry/AndrewParsons.–Secondedition. pagescm. Includesbibliographicalreferencesandindex. ISBN978-1-119-99915-7 (hardback)–ISBN978-1-119-99914-0(paperback) 1. Chemistry,Organic–Outlines,syllabi,etc. I. Title. QD256.5.P352014 547–dc23 2013024694 AcataloguerecordforthisbookisavailablefromtheBritishLibrary. HBISBN:9781119999157 PBISBN:9781119999140 Setin10/12ptTimesbyThomsonDigital,Noida,India. 1 2014 Contents Preface xi 1 Structureandbonding 1 1.1 Ionicversuscovalentbonds 1 1.2 Theoctetrule 2 1.3 Formalcharge 2 1.4 Sigma(s(cid:1))andpi(p(cid:1))bonds 3 1.5 Hybridisation 4 1.6 Inductiveeffects,hyperconjugationandmesomericeffects 6 1.6.1 Inductiveeffects 6 1.6.2 Hyperconjugation 7 1.6.3 Mesomericeffects 7 1.7 Acidityandbasicity 9 1.7.1 Acids 9 1.7.2 Bases 12 1.7.3 Lewisacidsandbases 15 1.7.4 Basicityandhybridisation 15 1.7.5 Acidityandaromaticity 16 1.7.6 Acid-basereactions 16 Workedexample 17 Problems 18 2 Functionalgroups,nomenclatureanddrawingorganiccompounds 21 2.1 Functionalgroups 21 2.2 Alkylandarylgroups 22 2.3 Alkylsubstitution 23 2.4 Namingcarbonchains 23 2.4.1 Specialcases 25 2.5 Drawingorganicstructures 27 Workedexample 28 Problems 29 3 Stereochemistry 31 3.1 Isomerism 31 3.2 Conformationalisomers 32 3.2.1 Conformationsofethane(CH CH ) 32 3 3 3.2.2 Conformationsofbutane(CH CH CH CH ) 33 3 2 2 3 3.2.3 Conformationsofcycloalkanes 34 vi Contents 3.2.4 Cyclohexane 35 3.3 Configurationalisomers 37 3.3.1 Alkenes 37 3.3.2 Isomerswithchiralcentres 38 Workedexample 44 Problems 45 4 Reactivityandmechanism 49 4.1 Reactiveintermediates:ionsversusradicals 49 4.2 Nucleophilesandelectrophiles 51 4.2.1 Relativestrength 52 4.3 Carbocations,carbanionsandcarbonradicals 53 4.3.1 Orderofstability 54 4.4 Stericeffects 55 4.5 Oxidationlevels 55 4.6 Generaltypesofreaction 56 4.6.1 Polarreactions(involvingionicintermediates) 56 4.6.2 Radicalreactions 58 4.6.3 Pericyclicreactions 59 4.7 Ionsversusradicals 59 4.8 Reactionselectivity 60 4.9 Reactionthermodynamicsandkinetics 60 4.9.1 Thermodynamics 60 4.9.2 Kinetics 62 4.9.3 Kineticversusthermodynamiccontrol 65 4.10 Orbitaloverlapandenergy 65 4.11 Guidelinesfordrawingreactionmechanisms 67 Workedexample 68 Problems 69 5 Halogenoalkanes 73 5.1 Structure 73 5.2 Preparation 74 5.2.1 Halogenationofalkanes 74 5.2.2 Halogenationofalcohols 75 5.2.3 Halogenationofalkenes 77 5.3 Reactions 78 5.3.1 Nucleophilicsubstitution 78 5.3.2 Elimination 84 5.3.3 Substitutionversuselimination 89 Workedexample 91 Problems 92 6 Alkenesandalkynes 95 6.1 Structure 95 6.2 Alkenes 97 Contents vii 6.2.1 Preparation 97 6.2.2 Reactions 98 6.3 Alkynes 110 6.3.1 Preparation 110 6.3.2 Reactions 110 Workedexample 113 Problems 114 7 Benzenes 117 7.1 Structure 117 7.2 Reactions 119 7.2.1 Halogenation 119 7.2.2 Nitration 120 7.2.3 Sulfonation 120 7.2.4 Alkylation:TheFriedel-Craftsalkylation 121 7.2.5 Acylation:TheFriedel-Craftsacylation 122 7.3 Reactivityofsubstitutedbenzenes 123 7.3.1 Reactivityofbenzenerings:Activating anddeactivatingsubstituents 124 7.3.2 Orientationofreactions 125 7.4 Nucleophilicaromaticsubstitution(theS Armechanism) 127 N 7.5 Theformationofbenzyne 128 7.6 Transformationofsidechains 129 7.7 Reductionofthebenzenering 132 7.8 Thesynthesisofsubstitutedbenzenes 132 7.9 Electrophilicsubstitutionofnaphthalene 135 7.10 Electrophilicsubstitutionofpyridine 135 7.11 Electrophilicsubstitutionofpyrrole,furanandthiophene 136 Workedexample 136 Problems 137 8 Carbonylcompounds:aldehydesandketones 139 8.1 Structure 139 8.2 Reactivity 140 8.3 Nucleophilicadditionreactions 142 8.3.1 Relativereactivityofaldehydesandketones 142 8.3.2 Typesofnucleophiles 142 8.3.3 Nucleophilicadditionofhydride:reduction 143 8.3.4 Nucleophilicadditionofcarbonnucleophiles: formationofC(cid:1)Cbonds 146 8.3.5 Nucleophilicadditionofoxygennucleophiles: formationofhydratesandacetals 149 8.3.6 Nucleophilicadditionofsulfurnucleophiles: formationofthioacetals 151 8.3.7 Nucleophilicadditionofaminenucleophiles: formationofiminesandenamines 152 viii Contents 8.4 a-Substitutionreactions 156 8.4.1 Keto-enoltautomerism 156 8.4.2 Reactivityofenols 157 8.4.3 Acidityofa-hydrogenatoms:enolateionformation 157 8.4.4 Reactivityofenolates 158 8.5 Carbonyl-carbonylcondensationreactions 160 8.5.1 Condensationsofaldehydesandketones: thealdolcondensationreaction 160 8.5.2 Crossedormixedaldolcondensations 161 8.5.3 Intramolecularaldolreactions 162 8.5.4 TheMichaelreaction 163 Workedexample 164 Problems 165 9 Carbonylcompounds:carboxylicacidsandderivatives 167 9.1 Structure 167 9.2 Reactivity 168 9.3 Nucleophilicacylsubstitutionreactions 168 9.3.1 Relativereactivityofcarboxylicacidderivatives 168 9.3.2 Reactivityofcarboxylicacidderivatives versuscarboxylicacids 169 9.3.3 Reactivityofcarboxylicacidderivatives versusaldehydes/ketones 169 9.4 Nucleophilicsubstitutionreactionsofcarboxylicacids 170 9.4.1 Preparationofacidchlorides 170 9.4.2 Preparationofesters(esterification) 170 9.5 Nucleophilicsubstitutionreactionsofacidchlorides 171 9.6 Nucleophilicsubstitutionreactionsofacidanhydrides 172 9.7 Nucleophilicsubstitutionreactionsofesters 173 9.8 Nucleophilicsubstitutionandreductionreactionsofamides 175 9.9 Nucleophilicadditionreactionsofnitriles 176 9.10 a-Substitutionreactionsofcarboxylicacids 178 9.11 Carbonyl-carbonylcondensationreactions 178 9.11.1 TheClaisencondensationreaction 178 9.11.2 CrossedormixedClaisencondensations 179 9.11.3 IntramolecularClaisencondensations: theDieckmannreaction 180 9.12 Asummaryofcarbonylreactivity 181 Workedexample 182 Problems 183 10 Spectroscopy 185 10.1 Massspectrometry(MS) 185 10.1.1 Introduction 185 10.1.2 Isotopepatterns 187 10.1.3 Determinationofmolecularformula 188