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Organic Chemistry

Additional Problems

Organic ChemistryAdditional Problems

Table of contents
  1. Dedication and Preface
  2. 1 Structure and Bonding
    1. Why This Chapter?
    2. 1.1 Atomic Structure: The Nucleus
    3. 1.2 Atomic Structure: Orbitals
    4. 1.3 Atomic Structure: Electron Configurations
    5. 1.4 Development of Chemical Bonding Theory
    6. 1.5 Describing Chemical Bonds: Valence Bond Theory
    7. 1.6 sp3 Hybrid Orbitals and the Structure of Methane
    8. 1.7 sp3 Hybrid Orbitals and the Structure of Ethane
    9. 1.8 sp2 Hybrid Orbitals and the Structure of Ethylene
    10. 1.9 sp Hybrid Orbitals and the Structure of Acetylene
    11. 1.10 Hybridization of Nitrogen, Oxygen, Phosphorus, and Sulfur
    12. 1.11 Describing Chemical Bonds: Molecular Orbital Theory
    13. 1.12 Drawing Chemical Structures
    14. Chemistry Matters—Organic Foods: Risk versus Benefit
    15. Key Terms
    16. Summary
    17. Additional Problems
  3. 2 Polar Covalent Bonds; Acids and Bases
    1. Why This Chapter?
    2. 2.1 Polar Covalent Bonds and Electronegativity
    3. 2.2 Polar Covalent Bonds and Dipole Moments
    4. 2.3 Formal Charges
    5. 2.4 Resonance
    6. 2.5 Rules for Resonance Forms
    7. 2.6 Drawing Resonance Forms
    8. 2.7 Acids and Bases: The Brønsted–Lowry Definition
    9. 2.8 Acid and Base Strength
    10. 2.9 Predicting Acid–Base Reactions from pKa Values
    11. 2.10 Organic Acids and Organic Bases
    12. 2.11 Acids and Bases: The Lewis Definition
    13. 2.12 Noncovalent Interactions between Molecules
    14. Chemistry Matters—Alkaloids: From Cocaine to Dental Anesthetics
    15. Key Terms
    16. Summary
    17. Additional Problems
  4. 3 Organic Compounds: Alkanes and Their Stereochemistry
    1. Why This Chapter?
    2. 3.1 Functional Groups
    3. 3.2 Alkanes and Alkane Isomers
    4. 3.3 Alkyl Groups
    5. 3.4 Naming Alkanes
    6. 3.5 Properties of Alkanes
    7. 3.6 Conformations of Ethane
    8. 3.7 Conformations of Other Alkanes
    9. Chemistry Matters—Gasoline
    10. Key Terms
    11. Summary
    12. Additional Problems
  5. 4 Organic Compounds: Cycloalkanes and Their Stereochemistry
    1. Why This Chapter?
    2. 4.1 Naming Cycloalkanes
    3. 4.2 Cis–Trans Isomerism in Cycloalkanes
    4. 4.3 Stability of Cycloalkanes: Ring Strain
    5. 4.4 Conformations of Cycloalkanes
    6. 4.5 Conformations of Cyclohexane
    7. 4.6 Axial and Equatorial Bonds in Cyclohexane
    8. 4.7 Conformations of Monosubstituted Cyclohexanes
    9. 4.8 Conformations of Disubstituted Cyclohexanes
    10. 4.9 Conformations of Polycyclic Molecules
    11. Chemistry Matters—Molecular Mechanics
    12. Key Terms
    13. Summary
    14. Additional Problems
  6. 5 Stereochemistry at Tetrahedral Centers
    1. Why This Chapter?
    2. 5.1 Enantiomers and the Tetrahedral Carbon
    3. 5.2 The Reason for Handedness in Molecules: Chirality
    4. 5.3 Optical Activity
    5. 5.4 Pasteur’s Discovery of Enantiomers
    6. 5.5 Sequence Rules for Specifying Configuration
    7. 5.6 Diastereomers
    8. 5.7 Meso Compounds
    9. 5.8 Racemic Mixtures and the Resolution of Enantiomers
    10. 5.9 A Review of Isomerism
    11. 5.10 Chirality at Nitrogen, Phosphorus, and Sulfur
    12. 5.11 Prochirality
    13. 5.12 Chirality in Nature and Chiral Environments
    14. Chemistry Matters—Chiral Drugs
    15. Key Terms
    16. Summary
    17. Additional Problems
  7. 6 An Overview of Organic Reactions
    1. Why This Chapter?
    2. 6.1 Kinds of Organic Reactions
    3. 6.2 How Organic Reactions Occur: Mechanisms
    4. 6.3 Polar Reactions
    5. 6.4 An Example of a Polar Reaction: Addition of HBr to Ethylene
    6. 6.5 Using Curved Arrows in Polar Reaction Mechanisms
    7. 6.6 Radical Reactions
    8. 6.7 Describing a Reaction: Equilibria, Rates, and Energy Changes
    9. 6.8 Describing a Reaction: Bond Dissociation Energies
    10. 6.9 Describing a Reaction: Energy Diagrams and Transition States
    11. 6.10 Describing a Reaction: Intermediates
    12. 6.11 A Comparison Between Biological Reactions and Laboratory Reactions
    13. Chemistry Matters—Where Do Drugs Come From?
    14. Key Terms
    15. Summary
    16. Additional Problems
  8. 7 Alkenes: Structure and Reactivity
    1. Why This Chapter?
    2. 7.1 Industrial Preparation and Use of Alkenes
    3. 7.2 Calculating the Degree of Unsaturation
    4. 7.3 Naming Alkenes
    5. 7.4 Cis–Trans Isomerism in Alkenes
    6. 7.5 Alkene Stereochemistry and the E,Z Designation
    7. 7.6 Stability of Alkenes
    8. 7.7 Electrophilic Addition Reactions of Alkenes
    9. 7.8 Orientation of Electrophilic Additions: Markovnikov’s Rule
    10. 7.9 Carbocation Structure and Stability
    11. 7.10 The Hammond Postulate
    12. 7.11 Evidence for the Mechanism of Electrophilic Additions: Carbocation Rearrangements
    13. Chemistry Matters—Bioprospecting: Hunting for Natural Products
    14. Key Terms
    15. Summary
    16. Additional Problems
  9. 8 Alkenes: Reactions and Synthesis
    1. Why This Chapter?
    2. 8.1 Preparing Alkenes: A Preview of Elimination Reactions
    3. 8.2 Halogenation of Alkenes: Addition of X2
    4. 8.3 Halohydrins from Alkenes: Addition of HO-X
    5. 8.4 Hydration of Alkenes: Addition of H2O by Oxymercuration
    6. 8.5 Hydration of Alkenes: Addition of H2O by Hydroboration
    7. 8.6 Reduction of Alkenes: Hydrogenation
    8. 8.7 Oxidation of Alkenes: Epoxidation and Hydroxylation
    9. 8.8 Oxidation of Alkenes: Cleavage to Carbonyl Compounds
    10. 8.9 Addition of Carbenes to Alkenes: Cyclopropane Synthesis
    11. 8.10 Radical Additions to Alkenes: Chain-Growth Polymers
    12. 8.11 Biological Additions of Radicals to Alkenes
    13. 8.12 Reaction Stereochemistry: Addition of H2O to an Achiral Alkene
    14. 8.13 Reaction Stereochemistry: Addition of H2O to a Chiral Alkene
    15. Chemistry Matters—Terpenes: Naturally Occurring Alkenes
    16. Key Terms
    17. Summary
    18. Summary of Reactions
    19. Additional Problems
  10. 9 Alkynes: An Introduction to Organic Synthesis
    1. Why This Chapter?
    2. 9.1 Naming Alkynes
    3. 9.2 Preparation of Alkynes: Elimination Reactions of Dihalides
    4. 9.3 Reactions of Alkynes: Addition of HX and X2
    5. 9.4 Hydration of Alkynes
    6. 9.5 Reduction of Alkynes
    7. 9.6 Oxidative Cleavage of Alkynes
    8. 9.7 Alkyne Acidity: Formation of Acetylide Anions
    9. 9.8 Alkylation of Acetylide Anions
    10. 9.9 An Introduction to Organic Synthesis
    11. Chemistry Matters—The Art of Organic Synthesis
    12. Key Terms
    13. Summary
    14. Summary of Reactions
    15. Additional Problems
  11. 10 Organohalides
    1. Why This Chapter?
    2. 10.1 Names and Structures of Alkyl Halides
    3. 10.2 Preparing Alkyl Halides from Alkanes: Radical Halogenation
    4. 10.3 Preparing Alkyl Halides from Alkenes: Allylic Bromination
    5. 10.4 Stability of the Allyl Radical: Resonance Revisited
    6. 10.5 Preparing Alkyl Halides from Alcohols
    7. 10.6 Reactions of Alkyl Halides: Grignard Reagents
    8. 10.7 Organometallic Coupling Reactions
    9. 10.8 Oxidation and Reduction in Organic Chemistry
    10. Chemistry Matters—Naturally Occurring Organohalides
    11. Key Terms
    12. Summary
    13. Summary of Reactions
    14. Additional Problems
  12. 11 Reactions of Alkyl Halides: Nucleophilic Substitutions and Eliminations
    1. Why This Chapter?
    2. 11.1 The Discovery of Nucleophilic Substitution Reactions
    3. 11.2 The SN2 Reaction
    4. 11.3 Characteristics of the SN2 Reaction
    5. 11.4 The SN1 Reaction
    6. 11.5 Characteristics of the SN1 Reaction
    7. 11.6 Biological Substitution Reactions
    8. 11.7 Elimination Reactions: Zaitsev’s Rule
    9. 11.8 The E2 Reaction and the Deuterium Isotope Effect
    10. 11.9 The E2 Reaction and Cyclohexane Conformation
    11. 11.10 The E1 and E1cB Reactions
    12. 11.11 Biological Elimination Reactions
    13. 11.12 A Summary of Reactivity: SN1, SN2, E1, E1cB, and E2
    14. Chemistry Matters—Green Chemistry
    15. Key Terms
    16. Summary
    17. Summary of Reactions
    18. Additional Problems
  13. 12 Structure Determination: Mass Spectrometry and Infrared Spectroscopy
    1. Why This Chapter?
    2. 12.1 Mass Spectrometry of Small Molecules: Magnetic-Sector Instruments
    3. 12.2 Interpreting Mass Spectra
    4. 12.3 Mass Spectrometry of Some Common Functional Groups
    5. 12.4 Mass Spectrometry in Biological Chemistry: Time-of-Flight (TOF) Instruments
    6. 12.5 Spectroscopy and the Electromagnetic Spectrum
    7. 12.6 Infrared Spectroscopy
    8. 12.7 Interpreting Infrared Spectra
    9. 12.8 Infrared Spectra of Some Common Functional Groups
    10. Chemistry Matters—X-Ray Crystallography
    11. Key Terms
    12. Summary
    13. Additional Problems
  14. 13 Structure Determination: Nuclear Magnetic Resonance Spectroscopy
    1. Why This Chapter?
    2. 13.1 Nuclear Magnetic Resonance Spectroscopy
    3. 13.2 The Nature of NMR Absorptions
    4. 13.3 Chemical Shifts
    5. 13.4 Chemical Shifts in 1H NMR Spectroscopy
    6. 13.5 Integration of 1H NMR Absorptions: Proton Counting
    7. 13.6 Spin–Spin Splitting in 1H NMR Spectra
    8. 13.7 1H NMR Spectroscopy and Proton Equivalence
    9. 13.8 More Complex Spin–Spin Splitting Patterns
    10. 13.9 Uses of 1H NMR Spectroscopy
    11. 13.10 13C NMR Spectroscopy: Signal Averaging and FT–NMR
    12. 13.11 Characteristics of 13C NMR Spectroscopy
    13. 13.12 DEPT 13C NMR Spectroscopy
    14. 13.13 Uses of 13C NMR Spectroscopy
    15. Chemistry Matters—Magnetic Resonance Imaging (MRI)
    16. Key Terms
    17. Summary
    18. Additional Problems
  15. 14 Conjugated Compounds and Ultraviolet Spectroscopy
    1. Why This Chapter?
    2. 14.1 Stability of Conjugated Dienes: Molecular Orbital Theory
    3. 14.2 Electrophilic Additions to Conjugated Dienes: Allylic Carbocations
    4. 14.3 Kinetic versus Thermodynamic Control of Reactions
    5. 14.4 The Diels–Alder Cycloaddition Reaction
    6. 14.5 Characteristics of the Diels–Alder Reaction
    7. 14.6 Diene Polymers: Natural and Synthetic Rubbers
    8. 14.7 Ultraviolet Spectroscopy
    9. 14.8 Interpreting Ultraviolet Spectra: The Effect of Conjugation
    10. 14.9 Conjugation, Color, and the Chemistry of Vision
    11. Chemistry Matters—Photolithography
    12. Key Terms
    13. Summary
    14. Summary of Reactions
    15. Additional Problems
  16. 15 Benzene and Aromaticity
    1. Why This Chapter?
    2. 15.1 Naming Aromatic Compounds
    3. 15.2 Structure and Stability of Benzene
    4. 15.3 Aromaticity and the Hückel 4n + 2 Rule
    5. 15.4 Aromatic Ions
    6. 15.5 Aromatic Heterocycles: Pyridine and Pyrrole
    7. 15.6 Polycyclic Aromatic Compounds
    8. 15.7 Spectroscopy of Aromatic Compounds
    9. Chemistry Matters—Aspirin, NSAIDs, and COX-2 Inhibitors
    10. Key Terms
    11. Summary
    12. Additional Problems
  17. 16 Chemistry of Benzene: Electrophilic Aromatic Substitution
    1. Why This Chapter?
    2. 16.1 Electrophilic Aromatic Substitution Reactions: Bromination
    3. 16.2 Other Aromatic Substitutions
    4. 16.3 Alkylation and Acylation of Aromatic Rings: The Friedel–Crafts Reaction
    5. 16.4 Substituent Effects in Electrophilic Substitutions
    6. 16.5 Trisubstituted Benzenes: Additivity of Effects
    7. 16.6 Nucleophilic Aromatic Substitution
    8. 16.7 Benzyne
    9. 16.8 Oxidation of Aromatic Compounds
    10. 16.9 Reduction of Aromatic Compounds
    11. 16.10 Synthesis of Polysubstituted Benzenes
    12. Chemistry Matters—Combinatorial Chemistry
    13. Key Terms
    14. Summary
    15. Summary of Reactions
    16. Additional Problems
  18. 17 Alcohols and Phenols
    1. Why This Chapter?
    2. 17.1 Naming Alcohols and Phenols
    3. 17.2 Properties of Alcohols and Phenols
    4. 17.3 Preparation of Alcohols: A Review
    5. 17.4 Alcohols from Carbonyl Compounds: Reduction
    6. 17.5 Alcohols from Carbonyl Compounds: Grignard Reaction
    7. 17.6 Reactions of Alcohols
    8. 17.7 Oxidation of Alcohols
    9. 17.8 Protection of Alcohols
    10. 17.9 Phenols and Their Uses
    11. 17.10 Reactions of Phenols
    12. 17.11 Spectroscopy of Alcohols and Phenols
    13. Chemistry Matters—Ethanol: Chemical, Drug, and Poison
    14. Key Terms
    15. Summary
    16. Summary of Reactions
    17. Additional Problems
  19. 18 Ethers and Epoxides; Thiols and Sulfides
    1. Why This Chapter?
    2. 18.1 Names and Properties of Ethers
    3. 18.2 Preparing Ethers
    4. 18.3 Reactions of Ethers: Acidic Cleavage
    5. 18.4 Cyclic Ethers: Epoxides
    6. 18.5 Reactions of Epoxides: Ring-Opening
    7. 18.6 Crown Ethers
    8. 18.7 Thiols and Sulfides
    9. 18.8 Spectroscopy of Ethers
    10. Chemistry Matters—Epoxy Resins and Adhesives
    11. Key Terms
    12. Summary
    13. Summary of Reactions
    14. Additional Problems
    15. Preview of Carbonyl Chemistry
  20. 19 Aldehydes and Ketones: Nucleophilic Addition Reactions
    1. Why This Chapter?
    2. 19.1 Naming Aldehydes and Ketones
    3. 19.2 Preparing Aldehydes and Ketones
    4. 19.3 Oxidation of Aldehydes and Ketones
    5. 19.4 Nucleophilic Addition Reactions of Aldehydes and Ketones
    6. 19.5 Nucleophilic Addition of H2O: Hydration
    7. 19.6 Nucleophilic Addition of HCN: Cyanohydrin Formation
    8. 19.7 Nucleophilic Addition of Hydride and Grignard Reagents: Alcohol Formation
    9. 19.8 Nucleophilic Addition of Amines: Imine and Enamine Formation
    10. 19.9 Nucleophilic Addition of Hydrazine: The Wolff–Kishner Reaction
    11. 19.10 Nucleophilic Addition of Alcohols: Acetal Formation
    12. 19.11 Nucleophilic Addition of Phosphorus Ylides: The Wittig Reaction
    13. 19.12 Biological Reductions
    14. 19.13 Conjugate Nucleophilic Addition to α,β‑Unsaturated Aldehydes and Ketones
    15. 19.14 Spectroscopy of Aldehydes and Ketones
    16. Chemistry Matters—Enantioselective Synthesis
    17. Key Terms
    18. Summary
    19. Summary of Reactions
    20. Additional Problems
  21. 20 Carboxylic Acids and Nitriles
    1. Why This Chapter?
    2. 20.1 Naming Carboxylic Acids and Nitriles
    3. 20.2 Structure and Properties of Carboxylic Acids
    4. 20.3 Biological Acids and the Henderson–Hasselbalch Equation
    5. 20.4 Substituent Effects on Acidity
    6. 20.5 Preparing Carboxylic Acids
    7. 20.6 Reactions of Carboxylic Acids: An Overview
    8. 20.7 Chemistry of Nitriles
    9. 20.8 Spectroscopy of Carboxylic Acids and Nitriles
    10. Chemistry Matters—Vitamin C
    11. Key Terms
    12. Summary
    13. Summary of Reactions
    14. Additional Problems
  22. 21 Carboxylic Acid Derivatives: Nucleophilic Acyl Substitution Reactions
    1. Why This Chapter?
    2. 21.1 Naming Carboxylic Acid Derivatives
    3. 21.2 Nucleophilic Acyl Substitution Reactions
    4. 21.3 Reactions of Carboxylic Acids
    5. 21.4 Chemistry of Acid Halides
    6. 21.5 Chemistry of Acid Anhydrides
    7. 21.6 Chemistry of Esters
    8. 21.7 Chemistry of Amides
    9. 21.8 Chemistry of Thioesters and Acyl Phosphates: Biological Carboxylic Acid Derivatives
    10. 21.9 Polyamides and Polyesters: Step-Growth Polymers
    11. 21.10 Spectroscopy of Carboxylic Acid Derivatives
    12. Chemistry Matters—β-Lactam Antibiotics
    13. Key Terms
    14. Summary
    15. Summary of Reactions
    16. Additional Problems
  23. 22 Carbonyl Alpha-Substitution Reactions
    1. Why This Chapter?
    2. 22.1 Keto–Enol Tautomerism
    3. 22.2 Reactivity of Enols: α-Substitution Reactions
    4. 22.3 Alpha Halogenation of Aldehydes and Ketones
    5. 22.4 Alpha Bromination of Carboxylic Acids
    6. 22.5 Acidity of Alpha Hydrogen Atoms: Enolate Ion Formation
    7. 22.6 Reactivity of Enolate Ions
    8. 22.7 Alkylation of Enolate Ions
    9. Chemistry Matters—Barbiturates
    10. Key Terms
    11. Summary
    12. Summary of Reactions
    13. Additional Problems
  24. 23 Carbonyl Condensation Reactions
    1. Why This Chapter?
    2. 23.1 Carbonyl Condensations: The Aldol Reaction
    3. 23.2 Carbonyl Condensations versus Alpha Substitutions
    4. 23.3 Dehydration of Aldol Products: Synthesis of Enones
    5. 23.4 Using Aldol Reactions in Synthesis
    6. 23.5 Mixed Aldol Reactions
    7. 23.6 Intramolecular Aldol Reactions
    8. 23.7 The Claisen Condensation Reaction
    9. 23.8 Mixed Claisen Condensations
    10. 23.9 Intramolecular Claisen Condensations: The Dieckmann Cyclization
    11. 23.10 Conjugate Carbonyl Additions: The Michael Reaction
    12. 23.11 Carbonyl Condensations with Enamines: The Stork Enamine Reaction
    13. 23.12 The Robinson Annulation Reaction
    14. 23.13 Some Biological Carbonyl Condensation Reactions
    15. Chemistry Matters—A Prologue to Metabolism
    16. Key Terms
    17. Summary
    18. Summary of Reactions
    19. Additional Problems
  25. 24 Amines and Heterocycles
    1. Why This Chapter?
    2. 24.1 Naming Amines
    3. 24.2 Structure and Properties of Amines
    4. 24.3 Basicity of Amines
    5. 24.4 Basicity of Arylamines
    6. 24.5 Biological Amines and the Henderson–Hasselbalch Equation
    7. 24.6 Synthesis of Amines
    8. 24.7 Reactions of Amines
    9. 24.8 Reactions of Arylamines
    10. 24.9 Heterocyclic Amines
    11. 24.10 Spectroscopy of Amines
    12. Chemistry Matters—Green Chemistry II: Ionic Liquids
    13. Key Terms
    14. Summary
    15. Summary of Reactions
    16. Additional Problems
  26. 25 Biomolecules: Carbohydrates
    1. Why This Chapter?
    2. 25.1 Classification of Carbohydrates
    3. 25.2 Representing Carbohydrate Stereochemistry: Fischer Projections
    4. 25.3 D,L Sugars
    5. 25.4 Configurations of the Aldoses
    6. 25.5 Cyclic Structures of Monosaccharides: Anomers
    7. 25.6 Reactions of Monosaccharides
    8. 25.7 The Eight Essential Monosaccharides
    9. 25.8 Disaccharides
    10. 25.9 Polysaccharides and Their Synthesis
    11. 25.10 Some Other Important Carbohydrates
    12. Chemistry Matters—Sweetness
    13. Key Terms
    14. Summary
    15. Summary of Reactions
    16. Additional Problems
  27. 26 Biomolecules: Amino Acids, Peptides, and Proteins
    1. Why This Chapter?
    2. 26.1 Structures of Amino Acids
    3. 26.2 Amino Acids and the Henderson–Hasselbalch Equation: Isoelectric Points
    4. 26.3 Synthesis of Amino Acids
    5. 26.4 Peptides and Proteins
    6. 26.5 Amino Acid Analysis of Peptides
    7. 26.6 Peptide Sequencing: The Edman Degradation
    8. 26.7 Peptide Synthesis
    9. 26.8 Automated Peptide Synthesis: The Merrifield Solid-Phase Method
    10. 26.9 Protein Structure
    11. 26.10 Enzymes and Coenzymes
    12. 26.11 How Do Enzymes Work? Citrate Synthase
    13. Chemistry Matters—The Protein Data Bank
    14. Key Terms
    15. Summary
    16. Summary of Reactions
    17. Additional Problems
  28. 27 Biomolecules: Lipids
    1. Why This Chapter?
    2. 27.1 Waxes, Fats, and Oils
    3. 27.2 Soap
    4. 27.3 Phospholipids
    5. 27.4 Prostaglandins and Other Eicosanoids
    6. 27.5 Terpenoids
    7. 27.6 Steroids
    8. 27.7 Biosynthesis of Steroids
    9. Chemistry Matters—Saturated Fats, Cholesterol, and Heart Disease
    10. Key Terms
    11. Summary
    12. Additional Problems
  29. 28 Biomolecules: Nucleic Acids
    1. Why This Chapter?
    2. 28.1 Nucleotides and Nucleic Acids
    3. 28.2 Base Pairing in DNA
    4. 28.3 Replication of DNA
    5. 28.4 Transcription of DNA
    6. 28.5 Translation of RNA: Protein Biosynthesis
    7. 28.6 DNA Sequencing
    8. 28.7 DNA Synthesis
    9. 28.8 The Polymerase Chain Reaction
    10. Chemistry Matters—DNA Fingerprinting
    11. Key Terms
    12. Summary
    13. Additional Problems
  30. 29 The Organic Chemistry of Metabolic Pathways
    1. Why This Chapter?
    2. 29.1 An Overview of Metabolism and Biochemical Energy
    3. 29.2 Catabolism of Triacylglycerols: The Fate of Glycerol
    4. 29.3 Catabolism of Triacylglycerols: β-Oxidation
    5. 29.4 Biosynthesis of Fatty Acids
    6. 29.5 Catabolism of Carbohydrates: Glycolysis
    7. 29.6 Conversion of Pyruvate to Acetyl CoA
    8. 29.7 The Citric Acid Cycle
    9. 29.8 Carbohydrate Biosynthesis: Gluconeogenesis
    10. 29.9 Catabolism of Proteins: Deamination
    11. 29.10 Some Conclusions about Biological Chemistry
    12. Chemistry Matters—Statin Drugs
    13. Key Terms
    14. Summary
    15. Additional Problems
  31. 30 Orbitals and Organic Chemistry: Pericyclic Reactions
    1. Why This Chapter?
    2. 30.1 Molecular Orbitals of Conjugated Pi Systems
    3. 30.2 Electrocyclic Reactions
    4. 30.3 Stereochemistry of Thermal Electrocyclic Reactions
    5. 30.4 Photochemical Electrocyclic Reactions
    6. 30.5 Cycloaddition Reactions
    7. 30.6 Stereochemistry of Cycloadditions
    8. 30.7 Sigmatropic Rearrangements
    9. 30.8 Some Examples of Sigmatropic Rearrangements
    10. 30.9 A Summary of Rules for Pericyclic Reactions
    11. Chemistry Matters—Vitamin D, the Sunshine Vitamin
    12. Key Terms
    13. Summary
    14. Additional Problems
  32. 31 Synthetic Polymers
    1. Why This Chapter?
    2. 31.1 Chain-Growth Polymers
    3. 31.2 Stereochemistry of Polymerization: Ziegler–Natta Catalysts
    4. 31.3 Copolymers
    5. 31.4 Step-Growth Polymers
    6. 31.5 Olefin Metathesis Polymerization
    7. 31.6 Intramolecular Olefin Metathesis
    8. 31.7 Polymer Structure and Physical Properties
    9. Chemistry Matters—Degradable Polymers
    10. Key Terms
    11. Summary
    12. Additional Problems
  33. A | Nomenclature of Polyfunctional Organic Compounds
  34. B | Acidity Constants for Some Organic Compounds
  35. C | Glossary
  36. D | Periodic Table
  37. Answer Key
    1. Chapter 1
    2. Chapter 2
    3. Chapter 3
    4. Chapter 4
    5. Chapter 5
    6. Chapter 6
    7. Chapter 7
    8. Chapter 8
    9. Chapter 9
    10. Chapter 10
    11. Chapter 11
    12. Chapter 12
    13. Chapter 13
    14. Chapter 14
    15. Chapter 15
    16. Chapter 16
    17. Chapter 17
    18. Chapter 18
    19. Chapter 19
    20. Chapter 20
    21. Chapter 21
    22. Chapter 22
    23. Chapter 23
    24. Chapter 24
    25. Chapter 25
    26. Chapter 26
    27. Chapter 27
    28. Chapter 28
    29. Chapter 29
    30. Chapter 30
    31. Chapter 31
  38. Index

18 • Additional Problems

18 • Additional Problems

Visualizing Chemistry

Problem 18-19
Give IUPAC names for the following compounds (red = O; reddish brown = Br; yellow = S):
(a)
The ball-and-stick model of the compound in which a six-membered ring is bonded with an ethyl group via an ether linkage.
(b)
The ball-and-stick model of the compound in which a six-membered cyclic ring is bonded with an epoxide ring. It has an alkene structure with a carbonyl group.
(c)
The ball-and-stick model of the compound in which a five-membered cyclic ring is bonded with an ethyl group to which a thiol group is bonded.
Problem 18-20

Show the product, including stereochemistry, that would result from reaction of the following epoxide with HBr:

A ball-and-stick model with a benzene ring linked to an epoxide ring which is connected to hydrogen and two methyl groups on both sides.
Problem 18-21

Show the product, including stereochemistry, of the following reaction:

The ball-and-stick model of the reactant having a six-membered ring fused with an epoxide ring reacts with methyl magnesium bromide, ether, and hydronium ion. The product is unknown.
Problem 18-22

Treatment of the following alkene with a peroxyacid yields an epoxide different from that obtained by reaction with aqueous Br2 followed by base treatment. Propose structures for the two epoxides, and explain the result.

The ball-and-stick model of cyclopentene ring with double bond at C 1, methyl groups on C 4, and a chain of two methylene groups connecting C 3 and C 5.

Mechanism Problems

Problem 18-23
Predict the product(s) and provide the mechanism for each of the following reactions.
(a)
2-Ethoxypropane reacts with hydrogen iodide (H I) to form an unknown product(s), depicted with a question mark.
(b)
Ethoxybenzene reacts with hydrogen bromide to form an unknown product(s), depicted with a question mark.
Problem 18-24
Predict the product(s) and provide the mechanism for each of the following reactions.
(a)
Tert-butyl ethyl ether reacts with hydrogen bromide to form an unknown product(s), depicted with a question mark.
(b)
Tert-butoxybenzene reacts with hydrogen bromide to form an unknown product(s), depicted with a question mark.
Problem 18-25
Predict the product(s) and provide the mechanism for each of the following two-step processes.
(a)
1-propanol reacts with sodium hydride, then 1-bromopropane to form an unknown product(s), depicted with a question mark.
(b)
Cyclopentanol reacts with sodium hydride, then methyl p-toluenesulfonate to form unknown product(s), depicted with a question mark.
Problem 18-26

The alkoxymercuration of alkenes involves the formation of an organomercury intermediate (I), which is reduced with NaBH4 to give an ether product. Predict the ether product and provide the mechanism for the following reaction.

Ethylidenecyclopentane reacts with mercury(II) trifluoroacetate and ethanol to create an intermediate (I), followed by reaction with sodium borohydride to form an unknown product(s), depicted with a question mark.
Problem 18-27
Predict the product(s) and provide the mechanism for the following reactions:
(a)
1,2-Epoxy-2-methylcyclohexane reacts with methylmagnesium bromide, then hydronium ion to form an unknown product(s), depicted with a question mark.
(b)
(2S)-ethyloxirane reacts with hydrogen bromide and ether to form an unknown product.
Problem 18-28
Predict the product(s) and provide the mechanism for each of the following reactions.
(a)
1,2-Epoxy-2-methylcyclohexane reacts with hydrogen bromide in the presence of ether to form an unknown product(s), depicted with a question mark.
(b)
Ethylene oxide with one carbon in common with a cyclohexane and a methyl on the other carbon (R configuration) reacts with hydronium to form unknown product(s).
Problem 18-29

In the formation of the prepolymer used to make epoxy resins, a bisphenol reacts with epichlorohydrin in the presence of a base. Show the product and mechanism when two moles of phenol react with epichlorohydrin.

A chemical reaction between two equivalents of phenol and epichlorohydrin with sodium hydroxide and water leads to form an unknown product(s), depicted with a question mark.
Problem 18-30

Ethers undergo an acid-catalyzed cleavage reaction when treated with the Lewis acid BBr3 at room temperature. Propose a mechanism for the reaction.

Anisole reacts with boron tribromide, then water to form phenol and methyl bromide.
Problem 18-31

Treatment of 1,1-diphenyl-1,2-epoxyethane with aqueous acid yields diphenyl acetaldehyde as the major product. Propose a mechanism for the reaction.

An epoxide ring bonded to two phenyl groups at C 2 reacts with hydronium ion to form an aldehyde product in which C 2 is bonded with two phenyl groups.
Problem 18-32

Fluoxetine, a heavily prescribed antidepressant marketed under the name Prozac, can be prepared by a route that begins with reaction between a phenol and an alkyl chloride.

4-trifluoromethylphenol reacts with an alkyl chloride with phenyl and amine groups in potassium hydroxide and D M S O to produce fluoxetine through a series of steps.
(a)
The rate of the reaction depends on both phenol and alkyl halide. Is this an SN1 or an SN2 reaction? Show the mechanism.
(b)
The physiologically active enantiomer of fluoxetine has (S) stereochemistry. Based on your answer in part (a), draw the structure of the alkyl chloride you would need, showing the correct stereochemistry.
Problem 18-33

When 2-methyl-2,5-pentanediol is treated with sulfuric acid, dehydration occurs and 2,2-dimethyltetrahydrofuran is formed. Suggest a mechanism for this reaction. Which of the two oxygen atoms is most likely to be eliminated, and why?

The structure of 2,2-dimethyltetrahydrofuran. It comprises a five-membered ring incorporating one oxygen, connected to two methyl groups at C2.
Problem 18-34
Methyl aryl ethers, such as anisole, are cleaved to iodomethane and a phenoxide ion by treatment with LiI in hot DMF. Propose a mechanism for this reaction.
Problem 18-35

The herbicide acifluorfen can be prepared by a route that begins with reaction between a phenol and an aryl fluoride. Propose a mechanism.

A substituted phenol and sutstituted aryl fluoride react in potassium hydride and dimethyl sulfoxide to yield acifluorfen through a series of steps.
Problem 18-36

Aldehydes and ketones undergo acid-catalyzed reaction with alcohols to yield hemiacetals, from aldehydes or ketals with ketones compounds that have one alcohol-like oxygen and one ether-like oxygen bonded to the same carbon. Further reaction of a hemiacetal with alcohol then yields an acetal, a compound that has two ether-like oxygens bonded to the same carbon.

A carbonyl and R O H react in acid catalyst to produce a hemiacetal; further reaction produces an acetal and water.
(a)
Show the structures of the hemiketal and ketal you would obtain by reaction of cyclohexanone with ethanol.
(b)
Propose a mechanism for the conversion of a hemiacetal into a ketal.
Problem 18-37

Propose a mechanism to account for the following transformation. What two kinds of reactions are occurring?

Two reactants, including a substituted benzene and maleic anhydride, undergo a heat-induced reaction to form a fused cyclohexene-cyclopentane compound with distinct molecular arrangements.

Naming Ethers

Problem 18-38
Draw structures corresponding to the following IUPAC names:
(a)
Ethyl 1-ethylpropyl ether
(b)
Di(p-chlorophenyl) ether
(c)
3,4-Dimethoxybenzoic acid
(d)
Cyclopentyloxycyclohexane
(e)
4-Allyl-2-methoxyphenol (eugenol; from oil of cloves)
Problem 18-39

Give IUPAC names for the following structures:

A ketone reacts with R O H and acid catalyst to make a hemiketal; this reacts with the same reactants again to produce a ketal and water.
(a)
A sulfur atom connected to a cyclohexane group and an isopropyl group.
(b)
A benzene ring with O C H 3 substituents on two adjacent carbons.
(c)
A five-membered ring in which two adjacent carbons are also connected by a shared oxygen atom.
(d)
A five-membered ring in which one member is an oxygen. The ring is numbered starting at oxygen (1); there is a C H 3 on C 2.
(e)
An oxygen atom connected to an isopropyl group and a cyclopropyl group.
(f)
A benzene ring with an S H substituent and, on an adjacent carbon, a nitro group.
(g)
A sulfur with an isopropyl on the right, and a five-carbon chain on the left with methyl groups on (from left) third, fourth, and fifth carbons.
(h)
A central carbon with two methyl and two methoxy substituents.
(i)
A cyclohexane in which one carbon is substituted with two S C H 3 groups.

Synthesizing Ethers

Problem 18-40
How would you prepare the following ethers?
(a)
A central oxygen connected to a benzene ring and an ethyl group.
(b)
A central oxygen connected to a benzene ring and an isopropyl group.
(c)
An oxirane drawn with oxygen on top, wedge hydrogen and dash methyl on left, and wedge methyl and dash hydrogen on right.
(d)
A central oxygen connected to a cyclopentane ring and a t-butyl group.
(e)
A cyclohexane with a wedge methoxy and dash hydrogen on one carbon, and on the adjacent (clockwise) carbon, a wedge hydrogen and dash methoxy.
(f)
A cyclohexane with a wedge methoxy and dash hydrogen on one carbon, and on the adjacent (clockwise) carbon, a wedge deuterium and dash hydrogen.
Problem 18-41
How would you prepare the following compounds from 1-phenylethanol?
(a)
Methyl 1-phenylethyl ether
(b)
Phenylepoxyethane
(c)
tert-Butyl 1-phenylethyl ether
(d)
1-Phenylethanethiol
Problem 18-42
tert-Butyl ethers can be prepared by the reaction of an alcohol with 2-methylpropene in the presence of an acid catalyst. Propose a mechanism for this reaction.
Problem 18-43

Treatment of trans-2-chlorocyclohexanol with NaOH yields 1,2-epoxycyclohexane, but reaction of the cis isomer under the same conditions yields cyclohexanone. Propose mechanisms for both reactions, and explain why the different results are obtained.

Reactions alter trans-2-chlorocyclohexanol to 1,2-epoxycyclohexane and cis-2-chlorocyclohexanol isomer to cyclohexanone, each utilizing sodium hydroxide and water.

Reactions of Ethers and Epoxides

Problem 18-44
Predict the products of the following ether cleavage reactions:
(a)
Cyclohexyl ethyl ether reacts with hydroiodic acid and water to produce unknown product(s), depicted by a question mark.
(b)
T-butyl phenyl ether reacts with trifluoroacetic acid to produce unknown product(s), depicted by a question mark.
(c)
Ethyl vinyl ether reacts with hydroiodic acid and water to produce unknown product(s), depicted by a question mark.
(d)
Ethyl neopentyl ether reacts with hydroiodic acid and water to produce unknown product(s), depicted by a question mark.
Problem 18-45
How would you carry out the following transformations? More than one step may be required.
(a)
Cyclohexene reacts with unknown reagent(s) to produce cyclohexyl ethyl ether.
(b)
Cis-1-methoxy-4-methylcyclohexane reacts with unknown reagent(s) to produce trans-1-bromo-4-methylcyclohexane.
(c)
4-t-butylcyclohexene reacts with unknown reagent(s) to produce cyclohexane with (counterclockwise) wedge hydroxide on C 1, dash hydroxide on C 2, wedge t-butyl on C 4.
(d)
1-hexyne is converted into hexyl methyl ether in the presence of an unknown reactant(s), depicted by a question mark.
(e)
1-hexyne is converted into 2-methoxyhexane in the presence of an unknown reactant(s), depicted by a question mark.
Problem 18-46
What product would you expect from cleavage of tetrahydrofuran with HI?
Problem 18-47
Write the mechanism of the hydrolysis of cis-5,6-epoxydecane by reaction with aqueous acid. What is the stereochemistry of the product, assuming normal backside SN2 attack?
Problem 18-48
What is the stereochemistry of the product from acid-catalyzed hydrolysis of trans-5,6-epoxydecane? How does the product differ from that formed in Problem 18-47?
Problem 18-49
Acid-catalyzed hydrolysis of a 1,2-epoxycyclohexane produces a trans-diaxial 1,2-diol. What product would you expect to obtain from acidic hydrolysis of cis-3-tert-butyl-1,2-epoxycyclohexane? (Recall that the bulky tert-butyl group locks the cyclohexane ring into a specific conformation.)
Problem 18-50

Imagine that you have treated (2R,3R)-2,3-epoxy-3-methylpentane with aqueous acid to carry out a ring-opening reaction.

The structure of 2,3-epoxy-3-methylpentane shows a 3-membered ring with oxygen and two carbon atoms, one bonded to hydrogen and methyl, the other to methyl and ethyl groups.
(a)
Draw the epoxide, showing stereochemistry.
(b)
Draw and name the product, showing stereochemistry.
(c)
Is the product chiral? Explain.
(d)
Is the product optically active? Explain.
Problem 18-51

Epoxides are reduced by treatment with lithium aluminum hydride to yield alcohols. Propose a mechanism for this reaction.

Cyclohexene oxide reacts with lithium aluminum hydride in ether, then hydronium, to form cyclohexanol.
Problem 18-52
Show the structure and stereochemistry of the alcohol that would result if 1,2-epoxycyclohexane were reduced with lithium aluminum deuteride, LiAlD4 (Problem 18-51).

Spectroscopy

Problem 18-53

The red fox (Vulpes vulpes) uses a chemical communication system based on scent marks in urine. One component of fox urine is a sulfide whose mass spectrum has M+ = 116. IR spectroscopy shows an intense band at 890 cm–1, and 1H NMR spectroscopy reveals the following peaks:

  • 1.74 δ (3 H, singlet); 2.11 δ (3 H, singlet); 2.27 δ (2 H, triplet, J = 4.2 Hz); 2.57 δ (2 H, triplet, J = 4.2 Hz); 4.73 δ (2 H, broad)

Propose a structure consistent with these data. [Note: (CH3)2S absorbs at 2.1 δ].

Problem 18-54

Anethole, C10H12O, a major constituent of the oil of anise, has the 1H NMR spectrum shown. On careful oxidation with Na2Cr2O7, anethole yields p-methoxybenzoic acid. What is the structure of anethole? Assign all peaks in the NMR spectrum, and account for the observed splitting patterns.

Proton N M R with shifts at 1.84 (doublet), 3.76 (singlet), 6.09 and 6.36 (multiplets), 6.82 and 7.23 (doublets). Relative areas are 3.00, 3.00, 1.00, 1.00, 2.00, 2.00 respectively.
Problem 18-55
Propose structures for compounds that have the following 1H NMR spectra:
(a)

C5H12S (An –SH proton absorbs near 1.6 δ.)

Proton N M R with shifts at 0 (T M S), 0.99 (triplet), 1.34 (singlet), and 1.61 (quartet). Relative areas are 1.00, 2.00, and 1.00 respectively.
(b)

C9H11BrO

Proton N M R with shifts at 2.31 (pentet), 3.58 (triplet), 4.08 (triplet) 6.90 and 7.25 (multiplets). Relative areas are 1.00, 1.00, 1.00, 1.50, and 1.00 respectively.
(c)

C5H12O2

Proton N M R with shifts at 0 (T M S), 1.30 and 3.15 (singlets). Relative areas are 3.97 and 4.09 respectively.

General Problems

Problem 18-56
Predict the products of the following reactions:
(a)
Isobutyl phenyl ether reacts with hydrogen bromide to form an unknown product(s) depicted by a question mark.
(b)
1-bromo-4-methylpentane reacts with thiourea, then sodium hydroxide and water to form an unknown product(s), depicted by a question mark.
(c)
Cyclopentanethiol reacts in the presence of bromine to form an unknown product(s), depicted by a question mark.
(d)
Cyclohexene with ethanethiol on C 4 reacts with hydrogen peroxide and water, to form an unknown product(s), depicted by a question mark.
Problem 18-57
How would you synthesize anethole (Problem 18-54) from phenol?
Problem 18-58
How could you prepare benzyl phenyl ether from benzene and phenol? More than one step is required.
Problem 18-59

Meerwein’s reagent, triethyloxonium tetrafluoroborate, is a powerful ethylating agent that converts alcohols into ethyl ethers at neutral pH. Show the reaction of Meerwein’s reagent with cyclohexanol, and account for the fact that trialkyloxonium salts are much more reactive alkylating agents than alkyl iodides.

(CH3CH2)3O+ BF4      Meerwein’s reagent

Problem 18-60

Safrole, a substance isolated from oil of sassafras, is used as a perfumery agent. Propose a synthesis of safrole from catechol (1,2-benzenediol).

The structure of safrole is a benzene ring with C 1 connected to C 2 by O C H 2 O, and with an allyl group on C 4.
Problem 18-61

Grignard reagents react with oxetane, a four-membered cyclic ether, to yield primary alcohols, but the reaction is much slower than the corresponding reaction with ethylene oxide. Suggest a reason for the difference in reactivity between oxetane and ethylene oxide.

Oxetane (four-membered ring incorporating one oxygen) reacts with R Mg X, then hydronium, to produce R C H 2 C H 2 C H 2 O H.
Problem 18-62
The Zeisel method is an old analytical procedure for determining the number of methoxyl groups in a compound. A weighed amount of the compound is heated with concentrated HI, ether cleavage occurs, and the iodomethane product is distilled off and passed into an alcohol solution of AgNO3, where it reacts to form a precipitate of silver iodide. The AgI is then collected and weighed, and the percentage of methoxyl groups in the sample is thereby determined. For example, 1.06 g of vanillin, the material responsible for the characteristic odor of vanilla, yields 1.60 g of AgI. If vanillin has a molecular weight of 152, how many methoxyl groups does it contain?
Problem 18-63
Disparlure, C19H38O, is a sex attractant released by the female spongy moth, Lymantria dispar. The 1H NMR spectrum of disparlure shows a large absorption in the alkane region, 1 to 2 δ, and a triplet at 2.8 δ. Treatment of disparlure, first with aqueous acid and then with KMnO4, yields two carboxylic acids identified as undecanoic acid and 6-methylheptanoic acid. (KMnO4 cleaves 1,2-diols to yield carboxylic acids.) Neglecting stereochemistry, propose a structure for disparlure. The actual compound is a chiral molecule with 7R,8S stereochemistry. Draw disparlure, showing the correct stereochemistry.
Problem 18-64
How would you synthesize racemic disparlure (Problem 18-63) from compounds having ten or fewer carbons?
Problem 18-65

How would you prepare o-hydroxyphenylacetaldehyde from phenol? More than one step is required.

O-Hydroxyphenylacetaldehyde has a structure in which a benzene ring has hydroxyl on one carbon, and C H 2 C H O on an adjacent carbon.
Problem 18-66

Identify the reagents ae in the following scheme:

Cyclohexanone is transformed into 1-methylcyclohexanol by reagent a; b and c convert 1-methylcyclohexanol to 1-methylcyclohexene and 1-methyl-1-methoxycyclohexane respectively. D converts 1-methylcyclohexene into 1,2-epoxy-1-methylcyclohexane, which is converted by e into (1S,2S)-1-methylcyclohexan-1,2-diol.
Problem 18-67
Propose structures for compounds that have the following 1H NMR spectra:
(a)

C4H10O2

Proton N M R with shifts at 0 (T M S), 1.27 (doublet), 3.31 (singlet), and 4.57 (quartet). Relative areas are 3.00, 6.00, and 1.00 respectively.
(b)

C9H10O

Proton N M R with shifts at 3.71 (singlet), 5.17 (doublet), 6.08 (doublet) 7.10 (multiplet), 7.25 (triplet), and 7.55 (multiplet). Relative areas are 3.00, 1.00, 1.00, 1.00, 2.00, 2.00 respectively.
Problem 18-68

We saw in Section 17.4 that ketones react with NaBH4 to yield alcohols. We’ll also see in Section 22.3 that ketones react with Br2 to yield α-bromo ketones. Perhaps surprisingly, treatment with NaBH4 of the α-bromo ketone from acetophenone yields an epoxide rather than a bromo alcohol. Show the structure of the epoxide, and explain its formation.

Acetophenone reacts with bromine to yield alpha-bromo acetophenone; subsequent treatment with sodium borohydride results in an epoxide with unknown structure.
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