Roos Organic Chemistry Concepts

An EFL Approach
1. Auflage 2014
ISBN: 978-0-12-801809-5
Verlag: Elsevier Science & Techn.
Format: EPUB
Kopierschutz: 6 - ePub Watermark

E-Book, Englisch, 236 Seiten

Organic Chemistry Concepts: An EFL Approach provides an introductory overview of the subject, to enable the reader to understand many critical, experimental facts. Designed to cover a single-semester course or a needed review on the principles of Organic Chemistry, the book is written and organized for readers whose first language is not English. Approximately 80% of the words used are drawn from the list of the 2,000 most common English words; the remaining 20% includes necessary technical words, common chemistry terms, and well-known academic words (per the Academic Word List). The book has been class-tested internationally as well as with native English speakers, and differs from other introductory textbooks in the subject both in its coverage and organization, with a particular focus on common problem areas.Focused on a limited number of functional classes, Organic Chemistry Concepts: An EFL Approach introduces those organic compounds early in the book. Once readers have a foundation of the concepts and language of organic chemistry, they can build from that knowledge and work with relatively complex molecules, such as some natural product types covered in a later chapter. The book describes basic level reaction mechanisms when instructive, and illustrations throughout to emphasize the 3D nature of organic chemistry. The book includes multiple pedagogical features, such as chapter questions and useful appendices, to support reader comprehension. - Covers all primary concepts in accessible language and pedagogical features, worked examples, glossary, chapter questions, illustrations, and useful summaries - Builds a foundation of key material through a structured framework from which readers can expand their understanding - Contains class-tested content written in a straightforward and accessible manner for non-native English speakers

Greg Roos' formal education comprised of a BSc (1971), BSc Honours (1972), and PhD in Organic Synthesis (1976) from the University of Cape Town. A postdoctoral fellowship with Richard Cookson at the University of Southampton was followed by a few years of pharmaceutical industrial experience. His fulltime academic career involved the University of Natal, South Africa (1981-1994), Murdoch University, Australia (1994-1997), and an extended period in the Middle East, including Sultan Qaboos University, Oman (1998-2004) and The Petroleum Institute, Abu Dhabi (2004-2008). He has successfully taught across various cultures and has received awards for his teaching contributions and innovations. Since 2009, as an adjunct Professor at Murdoch University, he shares his time between Australia and Dubai.His research interests have focused on the development of synthetic methodology, with particular interest in asymmetric processes. This provided numerous publications in the areas of the Baylis-Hillman reaction, imidazolidinone chiral auxiliaries, and dirhodium catalyst development and applications. This period also included a number of productive collaborative visits with Tony McKervey (University College Cork & Queen's University, Belfast), C. K. Sha (Shin Hua University, Taiwan), Mike Doyle (Trinity University, San Antonio), and Ron Warrener (CQU Rockhampton, Queensland). In 2001 he received the Merck Gold Medal for research from the South African Chemical Institute.

Autoren/Hrsg.

Roos, Gregory

Roos, Cathryn

Inhaltsverzeichnis

1;Front
Cover;1
2;Organic Chemistry Concepts:An EFL Approach;4
3;Copyright;5
4;Contents;6
5;PREFACE;10
6;How to Use This Book;12
7;Self-Learning Programs;14
8;CHAPTER 1 -
Organic Structures;16
8.1;1.1 WHAT IS ORGANIC CHEMISTRY?;16
8.2;1.2 WHAT MAKES CARBON SPECIAL?;16
8.3;1.3 MOLECULES, FORMULAE, AND STRUCTURES;17
8.4;1.4 BONDS AND SHAPE: THE HYBRIDIZATION MODEL;20
8.5;1.5 POLAR BONDS AND ELECTRONEGATIVITY;22
8.6;1.6 FORCES BETWEEN MOLECULES;23
8.7;QUESTIONS AND PROGRAMS;25
9;Chapter 2 - Functional Classes I, Structure and Naming;30
9.1;2.1 DRAWING AND NAMING MOLECULES;30
9.2;2.2 SATURATED HYDROCARBONS;30
9.3;2.3 SIMPLE UNSATURATED HYDROCARBONS (ALKENES AND ALKYNES);35
9.4;2.4 COMPLEX UNSATURATED SYSTEMS (POLYENES AND AROMATICS);37
9.5;2.5 ALKYL HALIDES;38
9.6;2.6 ALCOHOLS, PHENOLS, ETHERS, AND THEIR SULFUR EQUIVALENTS (THIOLS AND THIOETHERS);39
9.7;2.7 AMINES;41
9.8;2.8 COMPOUNDS WITH CARBONYL GROUPS;44
9.9;QUESTIONS AND PROGRAMS;50
10;Chapter 3 - Isomers and Stereochemistry;58
10.1;3.1 WHAT ARE ISOMERS?;58
10.2;3.2 STRUCTURAL ISOMERS;58
10.3;3.3 CONFORMATIONAL ISOMERS;59
10.4;3.4 GEOMETRIC (CIS-TRANS) ISOMERS;61
10.5;3.5 CONFIGURATIONAL ISOMERS;62
10.6;3.6 SUMMARY OF ISOMER RELATIONSHIPS;64
10.7;QUESTIONS AND PROGRAMS;65
11;Chapter 4 - Resonance and Delocalization;70
11.1;4.1 WHAT IS RESONANCE?;70
11.2;4.2 DRAWING USEFUL RESONANCE STRUCTURES;70
11.3;4.3 USING CURLY ARROWS TO COUNT ELECTRONS;72
11.4;QUESTIONS AND PROGRAMS;73
12;Chapter 5 - Reactivity: How and Why;80
12.1;5.1 WHY DO REACTIONS OCCUR?;80
12.2;5.2 BOND BREAKING AND MAKING;80
12.3;5.3 REACTIVE SPECIES;81
12.4;5.4 REACTION TYPES;84
12.5;5.5 REACTION MECHANISM: THE PATH FROM REACTANT TO PRODUCT;86
12.6;5.6 REACTION ENERGY;87
12.7;5.7 ORGANIC REDOX REACTIONS;88
12.8;QUESTIONS AND PROGRAMS;90
13;Chapter 6 - Acids and Bases;98
13.1;6.1 WHY ARE ACIDS AND BASES IMPORTANT?;98
13.2;6.2 GENERAL DEFINITIONS;98
13.3;6.3 ACIDITY OF CARBOXYLIC ACIDS;99
13.4;6.4 GENERAL FUNCTIONAL GROUP ACIDITY;102
13.5;6.5 GENERAL FUNCTIONAL GROUP BASICITY;106
13.6;QUESTIONS AND PROGRAMS;108
14;Chapter 7 - Functional Classes II, Reactions;118
14.1;7.1 FUNCTIONAL GROUP INTERCONVERSIONS;118
14.2;7.2 ALKANES;119
14.3;7.3 ALKENES;120
14.4;7.4 ALKYNES;125
14.5;7.5 ALKYL HALIDES;126
14.6;7.6 ALCOHOLS AND ETHERS;129
14.7;7.7 ALDEHYDES AND KETONES;132
14.8;7.8 CARBOXYLIC ACIDS AND ACYL DERIVATIVES;138
14.9;7.9 AMINES;142
14.10;7.10 AROMATIC COMPOUNDS;144
14.11;QUESTIONS AND PROGRAMS;147
15;Chapter 8 - Natural Product Biomolecules;166
15.1;8.1 WHAT ARE BIOMOLECULES?;166
15.2;8.2 CARBOHYDRATES;166
15.3;8.3 LIPIDS;170
15.4;8.4 AMINO ACIDS, PEPTIDES, AND PROTEINS;175
15.5;8.5 NUCLEIC ACIDS;178
15.6;QUESTIONS AND PROGRAMS;180
16;APPENDICES;186
16.1;APPENDIX 1: Electronegativity and Bond Polarity;186
16.2;APPENDIX 2: KEY IUPAC RULES FOR SUBSTITUTIVE NAMING OF ORGANIC COMPOUNDS;186
16.3;APPENDIX 3: SUBSTITUTIVE NAME PREFIXES AND SUFFIXES IN DECREASING ORDER OF PRIORITY;187
16.4;APPENDIX 4: FURTHER AMINE NOMENCLATURE;188
16.5;APPENDIX 5: E, Z-SEQUENCE RULES FOR GEOMETRIC ISOMERISM IN ALKENES;189
16.6;APPENDIX 6: CAHN-INGOLD-PRELOG R/S SEQUENCE RULES;189
16.7;APPENDIX 7: SELECTED AVERAGE BOND ENERGIES (KJ/MOL);190
16.8;APPENDIX 8: SYN- AND ANTI-ADDITION;190
16.9;APPENDIX 9: SUBSTITUTION STEREOCHEMISTRY;191
16.10;APPENDIX 10: FUNCTIONAL GROUP PREPARATIONS;191
16.11;APPENDIX 11: FUNCTIONAL GROUP TESTS;195
16.12;APPENDIX 12: MOST COMMON AMINO ACIDS;196
16.13;APPENDIX 12: MOST COMMON AMINO ACIDS—CONT’D;197
16.14;APPENDIX 13: EXAMPLES OF BIOLOGICAL SIGNIFICANCE;198
17;SOLUTIONS;202
17.1;CHAPTER 1: ORGANIC STRUCTURES;202
17.2;CHAPTER 2: FUNCTIONAL CLASSES I: STRUCTURE AND NAMING;204
17.3;CHAPTER 3: ISOMERS AND STEREOCHEMISTRY;208
17.4;CHAPTER 4: RESONANCE AND DELOCALIZATION;211
17.5;CHAPTER 5: REACTIVITY: HOW AND WHY;213
17.6;CHAPTER 6: ACIDS AND BASES;215
17.7;CHAPTER 7: FUNCTIONAL CLASSES II: REACTIONS;216
17.8;CHAPTER 8: NATURAL PRODUCT BIOMOLECULES;226
18;Glossary of Technical Definitions;230
19;Index;234

Leseproben

Chapter 2

Functional Classes I, Structure and Naming

Abstract

This chapter takes an initial look at the structure and representation of functional groups. The principles of the unambiguous systematic classification and naming of organic compounds are introduced. The importance of these for accurate information transfer is highlighted. Common functional classes are detailed and, where needed, three-dimensional diagrams, oxidation states, and physical properties are introduced.

Keywords

3-D drawings; Carbon oxidation states; Conjugation; Molecular diagrams; Physical properties; Systematic compound naming

2.1. Drawing and Naming Molecules

To understand the chemistry of organic molecules, we need to know the types of compounds that are possible. In this chapter we look at some details of the important functional classes introduced in Chapter 1. Each compound class is shown with structural diagrams (how to draw the compounds) and systematic naming of the compounds. This background knowledge will prepare you for the chemistry in later chapters.

2.2. Saturated Hydrocarbons

Hydrocarbon means that this class of compound has only carbon and hydrogen. In this broad grouping there are both:

? acyclic examples called alkanes;

? cyclic examples called cycloalkanes.

All saturated examples have only single s-bonds between sp3-hybridized carbon atoms and hydrogen atoms. This class gives the parent compounds from which all other functional types come from. They also serve as the parent compounds for systematic naming.

Hydrocarbons have low chemical reactivity. This is because they have no reactive functional group. They simply consist of chains of tetrahedral carbon atoms which are surrounded by hydrogen atoms. Table 2.1 gives a selection of hydrocarbons along with their physical properties of melting and boiling points. These low melting and boiling values show their overall non-polar character. Hydrocarbons can have “straight” chains (do not forget the shape caused by the tetrahedral carbon), branched chains, and cyclic variations.

For any of these subclasses, we can write a series of compounds that have the same basic structure, but differ from each other by a single extra –CH2– methylene group. Any series of compounds like these is called a homologous series and its members are homologs of each other.

2.2.1. Structural Diagrams

The purpose of a structural diagram is to show details for the arrangement of atoms in a particular compound. As shown in Figure 2.1, there are a number of ways to do this. The choice of method depends on the specific structural feature(s) of interest.

FIGURE 2.1 Structural diagrams.

Table 2.1

Parent Acyclic Alkanes and Cycloalkanes

Methane

CH4

CH4

-182

-162

Ethane

C2H6

CH3CH3

-183

-89

Propane

C3H8

CH3CH2CH3

-187

-42

Butane

C4H10

CH3(CH2)2CH3

-135

-0.5

Pentane

C5H12

CH3(CH2)3CH3

-130

36

Hexane

C6H14

CH3(CH2)4CH3

-94

69

Heptane

C7H16

CH3(CH2)5CH3

-91

98

Octane

C8H18

CH3(CH2)6CH3

-57

126

Nonane

C9H20

CH3(CH2)7CH3

-54

151

Decane

C10H22

CH3(CH2)8CH3

-30

174

Cyclopropane

C3H6

-127

-33

Cyclobutane

C4H8

-80

-13

Cyclopentane

C5H10

-194

49

Cyclohexane

C6H12

6.5

81

IUPAC, International Union of Pure and Applied Chemistry.

For the beginner, the full Lewis-type structure (extended) is the safest choice. Because every bond and atom is shown, we can avoid mistakes with the tetravalent nature of carbon. After practice with examples that have different structural features and functional groups, it becomes easier to use the shorter forms, such as condensed and bond line types.

The condensed forms use groups of atoms and show almost no detail of individual bonds. These groups can show all atoms, for example CH3– and –CH2–. Alternatively, accepted short forms can be used, for example Me– for CH3– and Et– for CH3CH2–. Often it is useful to use a combination of structural diagram forms. In these diagrams, only important features are shown in full detail.

You must take care to draw any bonds between the actual bonded atoms. This will avoid any mistakes with the valency (oxidation state) of the atoms involved. Note that only the bond line method shows the shape of the carbon framework. This is because every bend in the diagram represents a bonded group, for example –CH2–. The ends of lines represent CH3– groups.

It is also useful to be able to describe the degree of substitution at saturated sp3 carbon centers. This is simply done by counting the number of hydrogen atoms bonded to the particular carbon. As Figure 2.2 shows, this gives rise to four types:

? primary, with 3 Hs on carbon;

? secondary, with 2 Hs on carbon;

? tertiary, with 1 H on carbon;

? quaternary, with no Hs on carbon.

FIGURE 2.2 Classification of carbon centers.

It is also common to use the symbol –R to show general alkyl groups. A selection of these are detailed in Section 2.2.3 and are derived from alkanes by removing a hydrogen ligand.

In addition, as Figure 2.3 shows, there are different ways to show the three-dimensional (3-D) shape of tetrahedral sp3 centers. A tetrahedral center has four substituents, or attached groups. The most common is to show two adjacent substituents in the plane of the paper with normal bond lines. The other two substituents are drawn going into the paper with a dashed wedged bond, or coming out of the paper with a solid wedged bond.

FIGURE 2.3 Three-dimensional representations around atomic centers.

The Fischer projection is a less common alternative. By definition in these drawings, the vertical bonds go into the paper, and the horizontal bonds come out of the paper.

You do not always have to show the full stereochemistry (3-D shape) of a molecule. However, as you will see in Chapter 3, it is important not to forget that molecules have 3-D shapes.

2.2.2. Oxidation States for Carbon

This concept helps to create a link between the various classes of carbon compounds. The type and electronegativity of the atoms which are bonded to a carbon lets us assign nominal oxidation numbers to the various carbon atoms. These oxidation numbers indicate the relative gain or loss of electrons at the carbon in each compound type. This shows the relative equivalence of particular carbon oxidation states. From this, we can compare the oxidation levels of different functional groups.

The series of oxygen-containing functional classes in Figure 2.4 shows the principle. We can extend this process to other functional classes that involve other heteroatoms such as nitrogen, sulfur, and the halogens.

FIGURE 2.4 Nominal carbon oxidation numbers in functional classes.

Hydrogen is given the oxidation number of +1. Therefore, methane has carbon in its most reduced form of -4, which is its most stable, least reactive state. If a hydrogen atom is replaced with a bond to another carbon, the nominal oxidation number of the original carbon changes to -3. This is because we consider the carbons to have no effect on each other. The replacement of another hydrogen atom with a carbon, or the formation of a carbon–carbon double bond, then changes the oxidation number to -2, and so on.

Hydrocarbons (alkanes, alkenes, alkynes) can have carbons with nominal oxidation numbers ranging from -4 to 0. This depends on the number of other carbons attached. This follows the sequence from methane through 1°, 2°, 3°, and 4° carbon centers as was shown in Section 2.2.1. This helps us understand the different characteristics which they show in their reactions.

When we apply this process to common heteroatoms, they are all more electronegative than carbon and will count as -1 per bond....