Contents ix 10.1.4 Fragmentation patterns 10.1.5 Chemical ionisation(CD 10.2 The electromagnetic spectrum 10.3 Ultraviolet(UV)spectroscopy 10.4 Infrared (IR)spec oscopy 10.5 Nuclear magnetic resonance(NMR)spectroscopy 10.5.1 10.5.2 copy Worked example Problems 11 Natural products and synthetic polymers 11.1 Carbohydrates 11.2 Lipids 11.2.1 Waxes,fats and oils 11.2.2 Steroids 00010 11.3 Amino acids.peptides and proteins 1 11.4 Nucleic acids 213 11.5 Synthetic polymers 11.5.1 Addition polymers 11.5.2 Condensation polymers Worked example Problems Appendix 1:Bond dissociation enthalpies Appendix 2:Bond lengths Appendix 3:Approximate pKa values (relative to water) 2 Appendix 4:Useful abbreviations Appendix 5:Infrared absorptions 29 Appendix 6:Approximate NMR chemical shifts Appendix 7:Reaction summaries Appendix 8:Glossary 241 Further reading 2 Outline answer Index
10.1.4 Fragmentation patterns 188 10.1.5 Chemical ionisation (CI) 189 10.2 The electromagnetic spectrum 189 10.3 Ultraviolet (UV) spectroscopy 190 10.4 Infrared (IR) spectroscopy 192 10.5 Nuclear magnetic resonance (NMR) spectroscopy 194 10.5.1 1H NMR spectroscopy 197 10.5.2 13C NMR spectroscopy 202 Worked example 203 Problems 205 11 Natural products and synthetic polymers 207 11.1 Carbohydrates 207 11.2 Lipids 209 11.2.1 Waxes, fats and oils 209 11.2.2 Steroids 210 11.3 Amino acids, peptides and proteins 211 11.4 Nucleic acids 213 11.5 Synthetic polymers 214 11.5.1 Addition polymers 215 11.5.2 Condensation polymers 217 Worked example 218 Problems 219 Appendix 1: Bond dissociation enthalpies 221 Appendix 2: Bond lengths 223 Appendix 3: Approximate pKa values (relative to water) 225 Appendix 4: Useful abbreviations 227 Appendix 5: Infrared absorptions 229 Appendix 6: Approximate NMR chemical shifts 231 Appendix 7: Reaction summaries 235 Appendix 8: Glossary 241 Further reading 249 Outline answers 251 Index 277 Contents ix
Preface With the advent of modularisation and an eve reasing number of examina tions,ther ing ne ed fo otes that caps ulate the e ide for related emistry) in the UK.The text will also be appropria similar c oude ced ng t material pictorially (pictures eak word nce. latively few paragrap of text bu e are ann key phras /key inf ciples efinition ed to provide a struct red programme of revision Fu dament 1g, ona stry ar ntro important c of the e ity and m I to prov the reade ummary of the organi The ai ere Is pro which are nec following an em materia based on rea Inus,an o 2 rea an mechanisms are revisite in more de e follo chapters.Chapters 5-10 are treated essentially as 'case studies',reviewing the chemistry of the most important functional groups.Halogenoalkanes are discussed first and as these compounds undergo elimination reactions this is followed by the (electrophilic addition)reactions of alkenes and alkynes.This leads on to the contrasting (electrophilic substitution)reactivity of benzene and derivatives in Chapter 7.while the rich chemistry of carbonyl compounds is divided into Chapters 8 and 9.This division is made on the basis of the different reactivity (addition versus substitution)of aldehydes/ketones and carboxylic acid derivatives to nucleophiles.A chapter is included to revise the importance of spectroscopy in structure elucidation and,finally,the structure and reactivity of a number of important natural products and synthetic polymers is highlighted in Chapter 11.Worked examples and questions are included at the end of each chapter to test the reader's understanding,and outline answers are provided for all of the questions.Tables of useful physical data,reaction summaries and a glossary are included in appendices at the back of the book
Preface With the advent of modularisation and an ever-increasing number of examinations, there is a growing need for concise revision notes that encapsulate the key points of a subject in a meaningful fashion. This keynote revision guide provides concise organic chemistry notes for first year students studying chemistry and related courses (including biochemistry) in the UK. The text will also be appropriate for students on similar courses in other countries. An emphasis is placed on presenting the material pictorially (pictures speak louder than words); hence, there are relatively few paragraphs of text but numerous diagrams. These are annotated with key phrases that summarise important concepts/key information and bullet points are included to concisely highlight key principles and definitions. The material is organised to provide a structured programme of revision. Fundamental concepts, such as structure and bonding, functional group identification and stereochemistry are introduced in the first three chapters. An important chapter on reactivity and mechanism is included to provide a short overview of the basic principles of organic reactions. The aim here is to provide the reader with a summary of the ‘key tools’ which are necessary for understanding the following chapters and an important emphasis is placed on organisation of material based on reaction mechanism. Thus, an overview of general reaction pathways/mechanisms (such as substitution and addition) is included and these mechanisms are revisited in more detail in the following chapters. Chapters 5–10 are treated essentially as ‘case studies’, reviewing the chemistry of the most important functional groups. Halogenoalkanes are discussed first and as these compounds undergo elimination reactions this is followed by the (electrophilic addition) reactions of alkenes and alkynes. This leads on to the contrasting (electrophilic substitution) reactivity of benzene and derivatives in Chapter 7, while the rich chemistry of carbonyl compounds is divided into Chapters 8 and 9. This division is made on the basis of the different reactivity (addition versus substitution) of aldehydes/ketones and carboxylic acid derivatives to nucleophiles. A chapter is included to revise the importance of spectroscopy in structure elucidation and, finally, the structure and reactivity of a number of important natural products and synthetic polymers is highlighted in Chapter 11. Worked examples and questions are included at the end of each chapter to test the reader’s understanding, and outline answers are provided for all of the questions. Tables of useful physical data, reaction summaries and a glossary are included in appendices at the back of the book
xii Preface New to this edition A number of additions have been made to this edition to reflect the feedback from students and lecturers A second colour is used to clarify some of the diagrams.particularly the chanisticaspecsadedinthemargintohelpthereadlerfadnfomatonat Reference note to emphasise links between differento ms are included in the introducto Additional end-of-chapte rykey point for each chapter oblems (with outlin rs)are included .A worked example is included at the end of each chapter 。The informatio in the appendices has been expanded,including reaction summaries and a glossary Acknowledgements eople I would like to thank for their help with this projec rk.The also like t nstructive comm s p ald lik e to aul r n arah Tilley from Wiley,for all their help in progressing the second edition. Dr Andrew F.Pars 20153
New to this edition A number of additions have been made to this edition to reflect the feedback from students and lecturers: A second colour is used to clarify some of the diagrams, particularly the mechanistic aspects Reference notes are added in the margin to help the reader find information and to emphasise links between different topics Diagrams are included in the introductory key point sections for each chapter Additional end-of-chapter problems (with outline answers) are included A worked example is included at the end of each chapter The information in the appendices has been expanded, including reaction summaries and a glossary Acknowledgements There are numerous people I would like to thank for their help with this project. This includes many students and colleagues at York. Their constructive comments were invaluable. I would also like to thank my family for their support and patience throughout this project. Finally, I would like to thank Paul Deards and Sarah Tilley from Wiley, for all their help in progressing the second edition. Dr Andrew F. Parsons 2013 xii Preface
Structure and bonding Key point.Organic chemistry is the study of carbon compounds.lonic bonds involve elements gaining or losing electrons but the carbon atom is able to form four covalent bonds by sharing the four electrons in its outer shell.Single (C-C). double (C=C)or triple bonds(C=C)to carbon are possible.When carbon is bonded to a different element,the electrons are not shared equally.as electro- negative atoms (or groups)attract the electron density whereas electropositive atoms (or groups)repel the electron density.An understanding of the electron- withdrawing or-donating ability of atoms,or a group of atoms,can be used to predict whether an organic compound is a good base. resonance stabilisation of the allyl cation by inductive effed 8一H8入 e -H +M group three+lgroups 1.1 lonic versus covalent bonds lonic bonds are formed between molecules with opposite charges.The nega- eheernaianateondytheadeaia e.g.Na Covalent bonds are formed when a pair of electrons is shared between two atoms.A single line represents the two-electron bond. 0 Atom sg.GI-CI=。gag Aom— 0000
1 Structure and bonding Key point. Organic chemistry is the study of carbon compounds. Ionic bonds involve elements gaining or losing electrons but the carbon atom is able to form four covalent bonds by sharing the four electrons in its outer shell. Single (CC), double (CC) or triple bonds (CC) to carbon are possible. When carbon is bonded to a different element, the electrons are not shared equally, as electronegative atoms (or groups) attract the electron density whereas electropositive atoms (or groups) repel the electron density. An understanding of the electronwithdrawing or -donating ability of atoms, or a group of atoms, can be used to predict whether an organic compound is a good acid or base. CH2 H2C resonance stabilisation of the allyl cation +M group Et Et N Et H three +I groups conjugate acid of Et3N is stabilised by inductive effects 1.1 Ionic versus covalent bonds Ionic bonds are formed between molecules with opposite charges. The negatively charged anion will electrostatically attract the positively charged cation. This is present in (inorganic) salts. Cation Anion e.g. Na Cl Covalent bonds are formed when a pair of electrons is shared between two atoms. A single line represents the two-electron bond. Atom Atom Cl Cl e.g. o o o o o o Cl o o o o o o Cl o o Keynotes in Organic Chemistry, Second Edition. Andrew F. Parsons. 2014 John Wiley & Sons, Ltd. Published 2014 by John Wiley & Sons, Ltd.
2 Structure and bonding Coordinate for dative)bonds are formed when a pair of electrons is shared between two atoms.One atom donate s both electrons and a single line or an arrow represents the two-electron bond. THF)a electron acceptor O→BH or 8_8 electron donor .Hydrogen bonds are formed when the partially positive (+)hydrogen of one molecule interacts with the partially negative(-)heteroatom (e.g.oxygen or nitrogen)of another molecule. Molecueeteratom-MolealeHH 1.2 The octet rule To forondthe cabon atom shares electrons to give a stablell shell'elec ration of eight t valence electrons Methane is the smallest alkane- alkanes are a family of Methane(CHa) H8valence electrons H Section 2.4) G。+4 Hx-H2C2H=H-C-H H Lewis structure ral C is in group 14 and so has 4 valence electrons A line =2 electrons H is in group 1 and so has 1 valence electron A single bond contains two electrons,a double bond contains four electrons and a triple bond contains six electrons.A lone(or non-bonding)pair of electrons is represented by two dots () Carbon dioxide (CO) Hydrogen cyanide (HCN) 6:c竖d=0=c=g HCN文三H-C三N 1.3 Formal charge Formal positive or negative charges are assigned to atoms,which have an apparent 'abnormal'number of bonds
Coordinate (or dative) bonds are formed when a pair of electrons is shared between two atoms. One atom donates both electrons and a single line or an arrow represents the two-electron bond. O BH3 or O BH3 electron donor electron acceptor Hydrogen bonds are formed when the partially positive (dþ) hydrogen of one molecule interacts with the partially negative (d) heteroatom (e.g. oxygen or nitrogen) of another molecule. Molecule–H Heteroatom–Molecule e.g. HO H δ+ δ– δ+ δ– OH2 1.2 The octet rule To form organic compounds, the carbon atom shares electrons to give a stable ‘full shell’ electron configuration of eight valence electrons. H CH H H H CH H H o o o o + 4 H Methane (CH4) Lewis structure Full structural formula (or Kekulé structure) A line = 2 electrons 8 valence electrons C is in group 14 and so has 4 valence electrons X X X X C o X o o o H is in group 1 and so has 1 valence electron A single bond contains two electrons, a double bond contains four electrons and a triple bond contains six electrons. A lone (or non-bonding) pair of electrons is represented by two dots ( ). Carbon dioxide (CO2) Hydrogen cyanide (HCN) OCO o oo o H C N oo o o C X XXX O O XX XX XX XX C N X X H X X X X 1.3 Formal charge Formal positive or negative charges are assigned to atoms, which have an apparent ‘abnormal’ number of bonds. The cyclic ether is tetrahydrofuran (THF) and BH3 is called borane (Section 6.2.2.5) Intramolecular hydrogen bonding in carbonyl compounds is discussed in Section 8.4.1 Methane is the smallest alkane – alkanes are a family of compounds that contain only C and H atoms linked by single bonds (Section 2.4) Drawing organic compounds using full structural formulae and other conventions is discussed in Section 2.5 2 Structure and bonding