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1 Organic Chemistry Joseph M. Hornback University of Denver 5t Brooks/Cole Publishing Company I(T)P An International Thomson Publishing Company Pacific Grove 'Albany Belmont Bonn Boston Cincinnati Detroit Johannesburg London Madrid Melbourne Mexico City New York Paris Singapore Mjo Toronto Washington

2 Brief Contents JL A Simple Model for Chemical Bonds 1 /il Organic Compounds: A First Look 29 J) Orbitals and Bonding 59 Ah Proton Transfer: A Simple Reaction 105 J) Functional Groups and Nomenclature I 147 lu) Stereochemistry 183 II Nucleophilic Substitution Reactions 257 Elimination Reactions 309 j) Synthetic Uses of Substitution and Elimination Reactions 345 1(0) Additions to Carbon-Carbon Double and Triple Bonds 401 Functional Groups and Nomenclature II 461 Structure Determination by Spectroscopy I: Infrared and Nuclear Magnetic Resonance Spectroscopy 497

3 VÜi Brief Contents 13 Structure Determination by Spectroscopy II: Ultraviolet-Visible Spectroscopy and Mass Spectrometry Additions to the Carbonyl Group Substitutions at the Carbonyl Group 693 JLO Enolate and Other Carbon Nucleophiles Benzene and Aromatic Compounds 807 1(0) Aromatic Substitution Reactions The Chemistry of Radicals 903 2(0) Pericyclic Reactions The Synthesis of Organic Compounds 7007 Industrial Organic Chemistry Synthetic Polymers Carbohydrates Amino Acids, Peptides, and Proteins Nucleotides and Nucleic Acids 77S7 27/ Other Natural Products 7279

4 Contents 1 A Simple Model for Chemical Bonds 1.1 Introduction The Field of Organic Chemistry 1 Elaboration: The Death of the Vital Force Theory 1.3 Simple Atomic Structure Ionic Bonding Covalent Bonding Lewis Structures Covalent Ions Formal Charges Resonance Polar Bonds Shapes of Molecules Dipole Moments Summary 24 End-of-Chapter Problems 25 JL Organic Compounds: A First Look Introduction Common Bonding Situations Bond Strengths and Bond Lengths Structural Isomers 33 Elaboration: Life Based on Silicon? Degree of Unsaturation 39 Elaboration: Enumerating Structural Isomers 43 ix '

5 Contents 2.6 Physical Properties and Molecular Structure Melting Points, Boiling Points, and Solubilities 46 Elaboration: Melting Point of Cubane 47 Elaboration: Boiling Points of Fuels 48 Elaboration: A Chemical Handwarmer Introduction to Functional Croups Summary 53 End-of-Chapter Problems 53 3) Orbitals and Bonding Introduction Atomic Orbitals 59 Elaboration: Quantum Numbers Molecular Orbitals Single Bonds and sp 3 Hybridization Double Bonds and sp 2 Hybridization Triple Bonds and sp Hybridization Resonance and MO Theory Rules for Resonance Structures Types of Resonance Interactions 84 Elaboration: Resonance Stabilization of theallyl Radical 88 Elaboration: Resonance and the Bond Lengths of Naphthalene Molecular Orbital Energies 94 Elaboration: Reaction of Formaldehyde with Sodium Summary 97 End-of-Chapter Problems 99 4 Proton Transfer: A Simple Reaction Introduction Definitions The Acid-Base Equilibrium 109 Elaboration: Base Dissociation Constants Rate of the Acid-Base Reaction Effect of the Atom Bonded to the Hydrogen on Acidity 117

6 Contents 4.6 Inductive Effects Hydrogen Bonding Hybridization 123 Elaboration: Calcium Carbide Resonance Tables of Acids and Bases Substitution Reactions 134 Elaboration: Acidic and Basic Functional Groups 136 Elaboration: TheAcidity of Solvents 138 Elaboration: Superacids Summary 140 End-of-Chapter Problems 141 J) Functional Groups and Nomenclature I Introduction Alkanes Common Nomenclature of Alkanes 150 Elaboration: Energy Content of Fuels Systematic Nomenclature of Alkanes Systematic Nomenclature of Cycloalkanes Alkenes Alkynes Alkyl Halides Alcohols 168 Elaboration: Chlorinated Organic Compounds and the Environment 169 Elaboration: Chlorofluorocarbons and the Ozone Hole Ethers Amines Summary 178 End-of-Chapter Problems 178 (6) Stereochemistry Introduction Geometricai Isomers Designating the Connguration of Geometricai Isomers Conformations 192

7 6.5 Conformations of Cyclic Molecules Conformations of Cyclohexane Conformations of Other Rings Conformations of Cyclohexanes with One Substituent 208 Elaboration: How Much Strain Is Too Much? Conformations of Cyclohexanes with Two or More Substituents Chiral Molecules Recognizing Chiral Molecules Designating Configuration of Enantiomers Properties of Enantiomers 227 Elaboration: The D, L Methodfor Designating Absolute Configuration Molecules with Multiple Chiral Centers Stereoisomers and Cyclic Compounds Resolution: Separating Enantiomers Fischer Projections 239 Elaboration: History of the Development of an Understanding of Stereochemistry Reactions That Produce Enantiomers 244 Elaboration: Thalidomide and Chiral Synthesis 245 Elaboration: Other Chiral Compounds Summary 249 End-of-Chapter Problems 250 Nucleophilic Substitution Reactions Introduction The General Reaction Reaction Mechanisms Bimolecular Nucleophilic Substitution Stereochemistry of the S N 2 Reaction Effect of Substitutents on the Rate of the S N 2 Reaction Unimolecular Nucleophilic Substitution Stereochemistry of the S N 1 Reaction Effects of Substituents on the Rate of the S N 1 Reaction 274 Elaboration: The Triphenylmethyl Carbocation Leaving Groups 277 Elaboration: Experimental Evidencefor Inversion of Configuration in S N 2 Reactions 281

8 Contents xiii 7.11 Nucleophiles Effect of Solvent Competition Between S N 1 and S N 2 Reactions 288 Elaboration: Chemical Tests Involving S N 1 and S N 2 Reactions Intramolecular Reactions Competing Reactions 293 Elaboration: Carbocation Rearrangements in Superacids Summary 299 End-of-Chapter Problems 300 o Elimination Reactions Introduction The General Reaction Bimolecular Elimination 310 Elaboration: Investigating Mechanisms I: Kinetic Isotope Effects 311 Elaboration: DDT-Resistant Insects Stereochemistry of the E2 Reaction Direction of Elimination 318 Elaboration: Syn Eliminations Unimolecular Elimination 326 Elaboration: Investigating Mechanisms II: The Competition Between the S N 1 and El Pathways Regiochemistry and Stereochemistry of the El Reaction 329 Elaboration: The Elcb Mechanism The Competition Between Elimination and Substitution 332 Elaboration: Biological Elimination Reactions Summary 338 End-of-Chapter Problems Synthetic Uses of Substitution and Elimination Reactions Introduction Substitution Reactions 345

9 xiv Contents 9.3 Preparation of Alcohols Preparation of Ethers 349 Elaboration: Poisonous A Ikylating Agents Preparation of Esters Preparation of Alkyl Halides Preparation of Amines 361 Elaboration: Biological Methylations Preparation of Hydrocarbons Formation of Carbon-Carbon Bonds Phosphorus and Sulfur Nucleophiles Ring Opening of Epoxides 370 Elaboration: Sulfur Nucleophiles in Biochemistry Elimination Reactions 373 Elaboration: Uses of Epoxides in Industry Elimination of Hydrogen Halides (Dehydrohalogenation) Preparation of Alkynes Dehydration Eliminations to Form Carbon-Oxygen Double Bonds; Oxidation Reactions The Strategy of Organic Synthesis 383 Elaboration: Environmental^ Friendly Chemistry (Green Chemistry) 384 Elaboration: Cancer Chemotherapy Summary 389 End-of-Chapter Problems (0) Additions to Carbon-Carbon Double and Triple Bonds Introduction The General Mechanism Addition of Hydrogen Halides Addition of Halogens 409 Elaboration: Formation of Carbocations in Halogen Additions Halohydrin Formation Addition of Water (Hydration) 417 Elaboration: Industrial Addition Reactions Oxymercuration-Reduction 420

10 Contents XV 10.8 Hydroboration-Oxidation 424 Elaboration: Chiral Boranes in Organic Synthesis Addition of Carbenes 433 Elaboration: Singlet and Triplet Carbenes Epoxidation Hydroxylation Ozonolysis Catalytic Hydrogenation Additions to Conjugated Dienes 446 Elaboration: Asymmetrie Hydrogenation Summary 449 End-of-Chapter Problems 454 II Functional Groups and Nomenclature II Introduction Aromatic Hydrocarbons 461 Elaboration: Structure Proof by the Number of Isomers Phenols Aldehydes and Ketones Carboxylic Acids Derivatives of Carboxylic Acids 475 Elaboration: Fragrant Organic Compounds Sulfur and Phosphorus Compounds Nomenclature of Compounds with Several Functional Groups 488 Elaboration: Medicinal Uses of DMSO Summary 491 End-of-Chapter Problems ! Structure Determination by Spectroscopy I: Infrared and Nuclear Magnetic Resonance Spectroscopy Introduction Electromagnetic Radiation Interaction of Electromagnetic Radiation with Molecules The Electromagnetic Spectrum 501

11 12.5 Infrared Spectroscopy Generalizations The Hydrogen Region The Triple Bond Region 514 Elaboration: Remote Sensing of Automobile Pollutants The Double-Bond Region The Fingerprint Region Interpretation of IR Spectra 522 Elaboration: The Greenhouse Effect Nuclear Magnetic Resonance Spectroscopy Theory of ^-NMR The Chemical Shift Spin Coupling Complex Coupling Chemical Exchange Deuterium 558 Elaboration: NMR Spectroscopy of Carbocations in Superacid Interpretation of 'H-NMR Spectra 560 Elaboration: Magnetic Resonance Imaging Carbon-13 Magnetic Resonance Spectroscopy Solved Problems Employing IR and NMR Spectra 575 Elaboration: Use of NMR to Study Reactions Summary 587 End-of-Chapter Problems 588 Structure Determination by Spectroscopy II: Ultraviolet-Visible Spectroscopy and Mass Spectrometry Introduction Ultraviolet-Visible Spectroscopy Types of Electronic Transitions UV-Visible Spectroscopy in Structure Determination Mass Spectrometry 608 Elaboration: Ozone and Ultraviolet Radiation Determining the Molecular Formula Fragmentation of the Molecular Ion 616

12 * Contents xvii 13.8 Summary 626 Elaboration: Gas Chromatography and Mass Spectrometry 626 End-of-Chapter Problems Additions to the Carbonyl Group Introduction General Mechanisms Addition of Hydride; Reduction of Aldehydes and Ketones Addition of Water Addition of Hydrogen Cyanide Preparation and Properties of Organometallic Nucleophiles Addition of Organometallic Nucleophiles Addition of Phosphorus Ylides; The Wittig Reaction 653 Elaboration: Synthesis of Vitamin A Addition of Nitrogen Nucleophiles 659 Elaboration: Removal of Water 661 Elaboration: Methamphetamine Addition of Alcohols 667 Elaboration: Imines in Living Organisms Conjugate Additions Summary 678 End-of-Chapter Problems 682 Spectroscopy Problems Substitutions at the Carbonyl Group Introduction The General Mechanism Preparation of Acyl Chlorides Preparation of Anhydrides Preparation of Esters Preparation of Carboxylic Acids 705 Elaboration: The Preparation of Soap 708 Elaboration: Establishing the Mechanism of Saponification Preparation of Amides 715

13 Elaboration: Reaction Conditions Reaction with Hydride Nucleophiles Reduction of Acid Derivatives to Aldehydes Reactions with Organometallic Nucleophiles Preparation of Ketones Derivatives of Sulfur and Phosphorus Acids 728 Elaboration: Nerve Gases and Pesticides 730 Elaboration: ATP as an Energy Carrier Summary 734 End-of-Chapter Problems 739 Problems Involving Spectroscopy (6 Enolate and Other Carbon Nucleophiles Introduction Enols and Enolate Anions Alkylation of Enolate Anions 755 Elaboration: Isomerization of Sugars Alkylation of More Stabilized Anions The Aldol Condensation 765 Elaboration: The Reverse Aldol Reaction in Metabolism Ester Condensations 772 Elaboration: A n Industrial A Idol Reaction Enamines Other Carbon Nucleophiles Conjugate Additions Synthesis Summary 792 End-of-Chapter Problems 796 Problems Involving Spectroscopy Benzene and Aromatic Compounds Introduction Benzene Resonance Energy of Benzene Molecular Orbital Model for Cyclic Conjugated Molecules Cyclobutadiene Hückel's Rule 816

14 Contents xix 17.7 Cyclooctatetraene 817 Elaboration: Isomeric Cyclooctatetraenes Heterocyclic Aromatic Compounds Polycyclic Aromatic Hydrocarbons 822 Elaboration: Carcinogenic Polycyclic Aromatic Hydrocarbons 823 Elaboration: Buckminsterfullerene, A New Form of Carbon NMR and Aromaticity Annulenes Aromatic and Antiaromatic Ions Summary 830 End-of-Chapter Problems 831 Problems Involving Spectroscopy 834 lo Aromatic Substitution Reactions Introduction Mechanism for Electrophilic Aromatic Substitution Effect of Substitutents Effect of Multiple Substituents Nitration Halogenation Sulfonation Friedel-Crafts Alkylation 855 Elaboration: Synthetic Detergents Friedel-Crafts Acylation 860 Elaboration: Preparation of BHT and BHA Electrophilic Substitutions of Polycyclic Aromatic Compounds Nucleophilic Aromatic Substitution; Diazonium Ions Nucleophilic Aromatic Substitution; Addition-Elimination Nucleophilic Aromatic Substitution; Elimination-Addition 872 Elaboration: Experimental Evidencefor the Benzyne Mechanism 874 Elaboration: Herbicides, Disinfectants, Dioxin, and Agent Orange 875

15 Some Additional Useful Reactions 876 Synthesis of Aromatic Compounds 881 Summary 885 End-of-Chapter Problems 890 Problems Invoiving Spectroscopy The Chemistry of Radicals Introduction Radicals Stability of Radicals Geometry of Carbon Radicals Generation of Radicals General Radical Reactions 909 Elaboration: The Triphenylmethyl Radical Kolbe Electrolysis Halogenation Dehalogenation Autoxidation 921 Elaboration: The Industrial Preparation of Phenol 922 Elaboration: Vitamin E and Lipid Autoxidation Radical Additions to Alkenes Reductions and Radical Anions Summary 934 End-of-Chapter Problems 936 Problems Invoiving Spectroscopy 941 2(0) Pericyclic Reactions 20.1 Introduction Pericyclic Reactions MO Theory for Conjugated Molecules 20.4 Electrocyclic Reactions Examples of Electrocyclic Reactions Elaboration: Dewar Benzene Cycloaddition Reactions The Diels-Alder Reaction Elaboration: Diels-Alder Adducts as Pesticides Other Cycloaddition Reactions Sigmatropic Rearrangements Examples of Sigmatropic Rearrangements 977

16 < Contents xxi Elaboration: Degenerate Rearrangements 979 Elaboration: Suprafacial and Antarafacial Reactions 982 Elaboration: Pericyclic Reactions and Vitamin D Rearrangements to Electron Deficient Centers Summary 989 End-of-Chapter Problems 991 Problems Involving Spectroscopy The Synthesis of Organic Compounds Introduction Protective Groups for Alcohols Protective Groups for Aldehydes and Ketones Protective Groups for Carboxylic Acids Protective Groups for Amines Retrosynthetic Analysis 1010 Elaboration: Pheromones Examples of Syntheses Reactions That Form Carbon-Carbon Bonds Preparation of Functional Groups Summary 1035 End-of-Chapter Problems Industrial Organic Chemistry Introduction The Organic Chemical Industry Important Industrial Organic Chemicals Sources of Organic Chemicals Chemicals from Ethylene 1046 Elaboration: Carbonylation Reactions Chemicals from Propylene 1050 Elaboration: The Metathesis Reaction Chemicals from Benzene and Other Aromatic Compounds 1053 Elaboration: Industrial Electrophilic Aromatic Substitution Reactions 1056 Elaboration: Dioctyl Phthalate Plasticizer Chemicals from Butylene Chemicals from Other Sources 1063

17 xxii Contents Summary 1064 End-of-Chapter Problems 1065 Problems Involving Spectroscopy ] Synthetic Polymers Introduction Radical Chain Polymerization Structures of Polymers Ionic Polymerization 1076 Elaboration: Super Glue Coordination Polymerization Physical Properties of Polymers Major Thermoplastic Addition Polymers 1081 Elaboration: Teflon Elastomers 1084 Elaboration: Charles Goodyear and Vulcanization Condensation Polymers Thermoset Polymers 1092 Elaboration: Polybenzimidazole Chemical Properties of Polymers 1095 Elaboration: Recycling Plastics Summary 1098 End-of-Chapter Problems Carbohydrates Introduction Structures of Carbohydrates Stereochemistry of Carbohydrates 1104 Elaboration: R and S Nomenclature Applied to Sugars Cyclization of Monosaccharides Reactions of Monosaccharides 1113 Elaboration: Determination of Anomer Configuration 1114 Elaboration: A rtificial Sweeteners Fischer's Structure Proof for Glucose 1124 Elaboration: Emil Fischer 1130

18 Contents 24.7 Disaccharides Polysaccharides Other Carbohydrate-Containing Compounds 1134 Elaboration: Blood Groups Summary 1137 End-of-Chapter Problems 1138 Problems Involving Spectroscopy 1143 Amino Acids, Peptides, and Proteins Introduction Amino Acids Acid-Base Chemistry of Amino Acids Chemical Reactions of Amino Acids Laboratory Synthesis of Amino Acids 1153 Elaboration: Asymmetrie Synthesis of Amino Acids Peptides and Proteins 1159 Elaboration: Biosynthesis of Amino Acids from a-ketoacids 1160 Elaboration: NMR Spectra of Amides Sequencing Peptides Laboratory Synthesis of Peptides 1170 Elaboration: Frederick Sanger and the Sequence of Insulin Protein Structure Enzymes Summary 1182 End-of-Chapter Problems Nucleotides and Nucleic Acids Introduction Nucleosides and Nucleotides Structure of DNA and RNA 1190 Elaboration: Tautomers of Guanine and Thymine Replication, Transcription, and Translation 1196 Elaboration: Base-Catalyzed Hydrolysis of RNA 1196 Elaboration: The Treatment of AIDS with AZT Sequencing DNA 1200

19 xxiv Contents 26.6 Laboratory Synthesis of DNA 1207 Elaboration: Automated DNA Sequencing 1207 Elaboration: DNA Fingerprinting Summary 1212 End-of-Chapter Problems / Other Natural Products Introduction Terpenes Monoterpenes Sesquiterpenes Larger Terpenes 1228 Elaboration: Conformations of Decalin Steroids 1233 Elaboration: Syntheses That Mimic Nature Synthesis of Steroids 1237 Elaboration: The Birth Control Pill Alkaloids Fats and Related Compounds 1243 Elaboration: Partialfy Hydrogenated Vegetable Oil Prostaglandins 1246 Elaboration: Laboratory Synthesis of Prostaglandins Summary 1248 End-of-Chapter Problems 1249 Problems Involving Spectroscopy 1256 Appendix: Answers to Selected In-Chapter Problems AI Glossary Index II Gl