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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

8 • Additional Problems

8 • Additional Problems

Visualizing Chemistry

Problem 8-22
Name the following alkenes, and predict the products of their reaction with (1) meta-chloroperoxybenzoic acid, (2) KMnO4 in aqueous acid, (3) O3, followed by Zn in acetic acid:
(a)
The ball-and-stick model has a 7-carbon chain. C2 is bonded to a methyl group and double bonded to C3. C5 is bonded to a methyl group.
(b)
The ball-and-stick model has a cyclopentene ring. C3 is bonded to two methyl groups.
Problem 8-23
Draw the structures of alkenes that would yield the following alcohols on hydration (red = O). Tell in each case whether you would use hydroboration–oxidation or oxymercuration–demercuration.
(a)
The ball-and-stick model has a 5-carbon chain. C2 is bonded to a methyl group. C3 is bonded to a hydroxyl group and a methyl group. The red sphere denotes oxygen.
(b)
The ball-and-stick model has a cyclopentane ring. C1 is bonded to a hydroxyl group. C3 is bonded to two methyl groups. The red sphere denotes oxygen.
Problem 8-24

The following alkene undergoes hydroboration–oxidation to yield a single product rather than a mixture. Explain the result, and draw the product showing its stereochemistry.

The ball-and-stick model shows twisted cyclohexane with a double bond between C2-C3. C1 and C4 are connected by a 2-carbon chain, with one carbon bonded to a methyl.
Problem 8-25

From what alkene was the following 1,2-diol made, and what method was used, epoxide hydrolysis or OsO4?

The ball-and-stick model has a cyclohexane ring. C1 and C2 are each bonded to an equatorial hydroxyl group. C5 is bonded to a methyl group. The red sphere denotes oxygen.

Mechanism Problems

Problem 8-26
Predict the products for the following reactions, showing the complete mechanism and appropriate stereochemistry:
(a)
A reaction shows cyclohexene with C1 and C2 each bonded to a methyl group reacting with molecular bromine to form unknown product(s), depicted by a question mark.
(b)
A reaction shows benzene bonded to ethylene reacting with molecular chlorine to form unknown product(s), depicted by a question mark.
(c)
A reaction shows but-2-ene reacting with molecular chlorine to form unknown product(s), depicted by a question mark.
Problem 8-27
Draw the structures of the organoboranes formed when borane reacts with the following alkenes, including the regiochemistry and stereochemistry as appropriate. Propose a mechanism for each reaction.
(a)
The structure has a cyclobutene ring. C1 is bonded to a methyl group.
(b)
The structure has a 4-carbon chain. C1 is double bonded to C2.
(c)
The structure has a 2-carbon chain with a double bond   bonded to a benzene ring.
Problem 8-28
meta-Chlorobenzoic acid is not the only peroxyacid capable of epoxide formation. For each reaction below, predict the products and show the mechanism.
(a)
A   reaction shows  cyclohexene reacting with a methyl group at C1 reacts with C F 3 C O 3 H to form unknown product(s), depicted by a question mark.
(b)
A reaction shows  but-2-ene reacting with benzene that has C O 3 H group at C1 to form unknown product(s), depicted by a question mark.
Problem 8-29
Give the mechanism and products for the following acid-catalyzed epoxide-opening reactions, including appropriate stereochemistry.
(a)
A reaction shows cyclopentane reacting with C1 and C2 dash bonded to common oxygen reacts with hydronium ion to form unknown product(s), depicted by a question mark.
(b)
A reaction shows an oxirane ring with wedge-bonded methyl groups at C2 and C3 reacting with hydronium ion to form unknown product(s), depicted by a question mark.
(c)
A reaction shows an oxirane ring with dash bonded isopropyl at C2 and single bonded methyl group at C3 reacting with hydronium to form unknown product(s), depicted by question mark.
Problem 8-30

Which of the reactions below would result in a product mixture that would rotate plane-polarized light?

(a)Cyclohexane ring with double bonded methylene at C1 and dash bonded methyl at C4 reacting with hydrogen, palladium on carbon to form unknown product(s), depicted by question mark. (b)A reaction shows an oxirane with dash bonded methyl at C2 and wedge bonded methyl group at C3 reacting with hydronium to form unknown product(s), depicted by a question mark.
(c)A reaction shows 1-pentene with wedge-bonded methyl at C3 reactingwith ozone in first step and zinc, hydronium ion in the second step to form unknown product(s), depicted by question mark.

Problem 8-31
Reaction of 2-methylpropene with CH3OH in the presence of H2SO4 catalyst yields methyl tert-butyl ether, CH3OC(CH3)3, by a mechanism analogous to that of acid-catalyzed alkene hydration. Write the mechanism, using curved arrows for each step.
Problem 8-32

Iodine azide, IN3, adds to alkenes by an electrophilic mechanism similar to that of bromine. If a monosubstituted alkene such as 1-butene is used, only one product results:

A reaction shows 1-butene reacting with iodine azide to form product where C1 of butane is bonded to iodine an C2 is bonded to the azide group.
(a)
Add lone-pair electrons to the structure shown for IN3, and draw a second resonance form for the molecule.
(b)
Calculate formal charges for the atoms in both resonance structures you drew for IN3 in part (a).
(c)
In light of the result observed when IN3 adds to 1-butene, what is the polarity of the I − N3 bond? Propose a mechanism for the reaction using curved arrows to show the electron flow in each step.
Problem 8-33

10-Bromo-α-chamigrene, a compound isolated from marine algae, is thought to be biosynthesized from γ-bisabolene by the following route:

A 3-step reaction shows the formation of 10-bromo-alpha-chamigrene from gamma-bisabolene.

Draw the structures of the intermediate bromonium and cyclic carbocation, and propose mechanisms for all three steps.

Problem 8-34

Isolated from marine algae, prelaureatin is thought to be biosynthesized from laurediol by the following route. Propose a mechanism.

A reaction shows laurediol reacting with Br plus in the presence of bromoperoxidase to form prelaureatin.
Problem 8-35

Dichlorocarbene can be generated by heating sodium trichloroacetate. Propose a mechanism for the reaction, and use curved arrows to indicate the movement of electrons in each step. What relationship does your mechanism bear to the base-induced elimination of HCl from chloroform?

A reaction shows sodium trichloroacetate heated at 70 degrees Celsius to form dichlorocarbene, carbon dioxide, and sodium chloride.
Problem 8-36

Reaction of cyclohexene with mercury(II) acetate in CH3OH rather than H2O, followed by treatment with NaBH4, yields cyclohexyl methyl ether rather than cyclohexanol. Suggest a mechanism.

A reaction shows cyclohexene reacting with mercury (II) acetate in the presence of methanol and sodium borohydride to form cyclohexyl methyl ether.
Problem 8-37

Use your general knowledge of alkene chemistry to suggest a mechanism for the following reaction.

A reaction shows C15 sesquiterpene reacting with mercury (II) acetate to form a substituted decalin ring.
Problem 8-38

Treatment of 4-penten-1-ol with aqueous Br2 yields a cyclic bromo ether rather than the expected bromohydrin. Suggest a mechanism, using curved arrows to show electron movement.

A reaction shows 4-penten-1-ol reacting with molecular bromine in the presence of water to form 2-(bromomethyl)tetrahydrofuran.
Problem 8-39

Hydroboration of 2-methyl-2-pentene at 25 °C, followed by oxidation with alkaline H2O2, yields 2-methyl-3-pentanol, but hydroboration at 160 °C followed by oxidation yields 4-methyl-1-pentanol. Suggest a mechanism.

A 2-pathway reaction shows the formation of 2-methyl-3-pentanol and 4-methyl-1-pentanol from 2-methyl-2-pentene at slightly different reaction temperaures.

Reactions of Alkenes

Problem 8-40

Predict the products of the following reactions (the aromatic ring is unreactive in all cases). Indicate regiochemistry when relevant.

A  reaction shows styrene reacting with either  hydrogen-palladium, bromine, osmium tetroxide, aqueous chlorine, diiodomethane, or  meta-chloroperoxy-benzoic acid to form products, depicted by question marks.
Problem 8-41
Suggest structures for alkenes that give the following reaction products. There may be more than one answer for some cases.
(a)
A reaction shows an unknown reactant  reacting with hydrogen on palladium catalyst to form a 6-carbon chain with a methyl group at C2.
(b)
A reaction shows an unknown reactant reacting with hydrogen on palladium to form cyclohexane ring, in which C1 is bonded to two methyl groups.
(c)
A reaction shows an unknown reactant reacting with molecular bromine to form a product with 6-carbon chain. C2 and C3 each bond to bromine atom. C5 bonds to methyl group.
(d)
A reaction shows an unknown reactant reacting with HCl to form a product with a 7-carbon chain. C2 is bonded to chlorine atom. C3 is bonded to a methyl group.
(e)
A reaction shows an unknown reactant reacting with mercury (II) acetate in water and sodium borohydride to form 5-carbon chain, in which C2 is bonded to a hydroxyl group.
(f)
A reaction shows an unknown reactant reacting  with diiodomethane in presence of zinc-copper to form cyclohexane fused to cyclopropane.
Problem 8-42
Predict the products of the following reactions, showing both regiochemistry and stereochemistry where appropriate:
(a)
Cyclohexene with a methyl group at C1 reacts with ozone in step 1 and zinc in hydronium ion in step 2 to form unknown product(s), depicted by a question mark.
(b)
Cyclohexene reacts with potassium permanganate in presence of hydronium ion to form unknown product(s), depicted by a question mark.
(c)
Cyclohexene with methyl group at C1 reacts with borane in step 1 and hydrogen peroxide in hydroxide ion in step 2 to form unknown product(s), depicted by a question mark.
(d)
Cyclohexene with methyl group at C1 reacts with mercury (II) acetate in water in step 1 and sodium borohydride in step 2 to form unknown product(s), depicted by question mark.
Problem 8-43
Which reaction would you expect to be faster, addition of HBr to cyclohexene or to 1-methylcyclohexene? Explain.
Problem 8-44
What product will result from hydroboration–oxidation of 1-methylcyclopentene with deuterated borane, BD3? Show both the stereochemistry (spatial arrangement) and the regiochemistry (orientation) of the product.
Problem 8-45

The cis and trans isomers of 2-butene give different cyclopropane products in the Simmons–Smith reaction. Show the structures of both, and explain the difference.

cis-2-Butene reacts with diiodomethane and copper-zinc catalyst to form unknown product(s). trans-2-Butene also reacts with the same reagent and catalyst to form unknown product(s). Products are depicted by question marks.
Problem 8-46

Predict the products of the following reactions. Don’t worry about the size of the molecule; concentrate on the functional groups.

Cholesterol undergoes multiple reactions with different sets of reagents to form five different unknown product(s), labeled A through E.
Problem 8-47

Addition of HCl to 1-methoxycyclohexene yields 1-chloro-1-methoxycyclohexane as a sole product. Use resonance structures of the carbocation intermediate to explain why none of the alternate regioisomer is formed.

A reaction shows 1-methoxycyclohexene reacting with hydrochloric acid to form 1-chloro-1-methoxycyclohexene.

Synthesis Using Alkenes

Problem 8-48
How would you carry out the following transformations? What reagents would you use in each case?
(a)
Cyclopentene reacts with unknown reagent(s), depicted by a question mark to form cyclopentane, in which C1 and C2 are dash-bonded to a hydrogen atom and wedge-bonded to a hydroxyl group.
(b)
Cyclopentene reacts with unknown reagent(s), depicted by a question mark, to form cyclopentane, in which C1 is bonded to a hydroxyl group.
(c)
Cyclopentene reacts with unknown reagent(s), depicted by a question mark, to form cyclopentane fused to cyclopropane, in which C1 is bonded to two chlorine atoms.
(d)
Cyclohexane with a methyl and hydroxyl group at C1 reacts with unknown reagent(s), depicted by a question mark to form cyclohexene, in which C1 is bonded to a methyl group.
(e)
A reaction shows 3-methyl-2-pentene reacting with unknown reagent(s) to form acetaldehyde and a 3-carbon chain with double-bonded oxygen at C1 and methyl at C2.
(f)
A reaction shows 2-methylpropene reacting with unknown reagent(s)  to form a 3-carbon chain, in which C1 and C2 are bonded to hydroxyl and methyl, respectively.
Problem 8-49
Draw the structure of an alkene that yields only acetone, (CH3)2C = O, on ozonolysis followed by treatment with Zn.
Problem 8-50
Show the structures of alkenes that give the following products on oxidative cleavage with KMnO4 in acidic solution:
(a)
The condensed formulas of two products, propionic acid and carbon dioxide.
(b)
The condensed formulas of two products, acetone and butyric acid.
(c)
The condensed formulas of two products, cyclohexanone  and acetone.
(d)
The condensed structural formula has an 8-carbon chain. C1 is a carboxylic acid group. C6 is a carbonyl group.
Problem 8-51
In planning the synthesis of one compound from another, it’s just as important to know what not to do as to know what to do. The following reactions all have serious drawbacks to them. Explain the potential problems of each.
(a)
A reaction shows 2-methyl-2-butene reacting with hydrogen iodide to form a 4-carbon chain, in which C2 is bonded to iodine and C3 is bonded to a methyl group.
(b)
A reaction shows cyclopentene reacting with osmium tetroxide and sodium bicarbonate to form cyclopentane, in which C1 is wedge bonded to hydroxyl. C2 is dash bonded to hydroxyl group.
(c)
A reaction shows yclohexadiene reacting with ozone and zinc to form a 6-carbon chain, in which C1 and C6 are aldehyde groups. C3 is double bonded to C4.
(d)
A reaction shows 1-methylcyclohexene reacting with borane and basic hydrogen peroxide to form a cyclohexanol in which  C1 is wedge bonded to methyl and C2 is wedge bonded to hydroxyl.
Problem 8-52

Which of the following alcohols could not be made selectively by hydroboration–oxidation of an alkene? Explain.

(a)The condensed structural formula has a 5-carbon chain. C2 is bonded to a hydroxyl group.(b)The condensed structural formula has a 4-carbon chain. C2 is bonded to a hydroxyl group and C1 and C4 to methyl groups(c)The structure has a cyclohexane ring. C1 is wedge bonded to a methyl group. C2 is wedge bonded to a hydroxyl group.(d)The structure has a cyclohexane ring. C1 is wedge bonded to a methyl group and dash bonded to a hydroxyl group.

Polymers

Problem 8-53

Plexiglas, a clear plastic used to make many molded articles, is made by polymerization of methyl methacrylate. Draw a representative segment of Plexiglas.

The structure of methyl methacrylate.
Problem 8-54

Poly(vinyl pyrrolidone), prepared from N-vinylpyrrolidone, is used both in cosmetics and as a component of a synthetic substitute for blood. Draw a representative segment of the polymer.

The structure of N-vinylpyrrolidone.
Problem 8-55

When a single alkene monomer, such as ethylene, is polymerized, the product is a homopolymer. If a mixture of two alkene monomers is polymerized, however, a copolymer often results. The following structure represents a segment of a copolymer called Saran. What two monomers were copolymerized to make Saran?

Saran is a copolymer with a repeating  4-carbon chain containing two chlorine atoms bonded to C2  bonded and one chlorine atom bonded to C4.

General Problems

Problem 8-56
Compound A has the formula C10H16. On catalytic hydrogenation over palladium, it reacts with only 1 molar equivalent of H2. Compound A also undergoes reaction with ozone, followed by zinc treatment, to yield a symmetrical diketone, B (C10H16O2).
(a)
How many rings does A have?
(b)
What are the structures of A and B?
(c)
Write the reactions.
Problem 8-57
An unknown hydrocarbon A with the formula C6H12 reacts with 1 molar equivalent of H2 over a palladium catalyst. Hydrocarbon A also reacts with OsO4 to give diol B. When oxidized with KMnO4 in acidic solution, A gives two fragments. One fragment is propanoic acid, CH3CH2CO2H, and the other fragment is ketone C. What are the structures of A, B, and C? Write all reactions.
Problem 8-58

Using an oxidative cleavage reaction, explain how you would distinguish between the following two isomeric dienes:

The figure shows two isomeric dienes. Cyclohexadiene has double bonds at C1 and C3. Another cyclohexadiene has double bonds at C1 and C4.
Problem 8-59

Compound A, C10H18O, undergoes reaction with dilute H2SO4 at 50 °C to yield a mixture of two alkenes, C10H16. The major alkene product, B, gives only cyclopentanone after ozone treatment followed by reduction with zinc in acetic acid. Identify A and B, and write the reactions.

The structure of cyclopentanone.
Problem 8-60

Draw the structure of a hydrocarbon that absorbs 2 molar equivalents of H2 on catalytic hydrogenation and gives only butanedial on ozonolysis.

The structure of butanedial.
Problem 8-61
Simmons–Smith reaction of cyclohexene with diiodomethane gives a single cyclopropane product, but the analogous reaction of cyclohexene with 1,1-diiodoethane gives (in low yield) a mixture of two isomeric methylcyclopropane products. What are the two products, and how do they differ?
Problem 8-62
The sex attractant of the common housefly is a hydrocarbon with the formula C23H46. On treatment with aqueous acidic KMnO4, two products are obtained, CH3(CH2)12CO2H and CH3(CH2)7CO2H. Propose a structure.
Problem 8-63
Compound A has the formula C8H8. It reacts rapidly with KMnO4 to give CO2 and a carboxylic acid, B (C7H6O2), but reacts with only 1 molar equivalent of H2 on catalytic hydrogenation over a palladium catalyst. On hydrogenation under conditions that reduce aromatic rings, 4 equivalents of H2 are taken up and hydrocarbon C (C8H16) is produced. What are the structures of A, B, and C? Write the reactions.
Problem 8-64
How would you distinguish between the following pairs of compounds using simple chemical tests? Tell what you would do and what you would see.
(a)
Cyclopentene and cyclopentane
(b)
2-Hexene and benzene
Problem 8-65

α-Terpinene, C10H16, is a pleasant-smelling hydrocarbon that has been isolated from oil of marjoram. On hydrogenation over a palladium catalyst, α-terpinene reacts with 2 molar equivalents of H2 to yield a hydrocarbon, C10H20. On ozonolysis, followed by reduction with zinc and acetic acid, α-terpinene yields two products, glyoxal and 6-methyl-2,5-heptanedione.

The structures of glyoxal and 6-methyl-2,5-heptanedione.
(a)
How many degrees of unsaturation does α-terpinene have?
(b)
How many double bonds and how many rings does it have?
(c)
Propose a structure for α-terpinene.
Problem 8-66

Evidence that cleavage of 1,2-diols by HIO4 occurs through a five-membered cyclic periodate intermediate is based on the measurement of reaction rates. When diols A and B were prepared and the rates of their reaction with HIO4 were measured, it was found that diol A cleaved approximately 1 million times faster than diol B. Make molecular models of A and B and of potential cyclic periodate intermediates, and then explain the results.

Structure A (cis diol) shows bicyclic heptane with hydroxyls at the top of C2 and C3. Structure B (trans diol) shows a hydroxyl group at the bottom of C 2.
Problem 8-67

Reaction of HBr with 3-methylcyclohexene yields a mixture of four products: cis- and trans-1-bromo-3-methylcyclohexane and cis- and trans-1-bromo-2-methylcyclohexane. The analogous reaction of HBr with 3-bromocyclohexene yields trans-1,2-dibromocyclohexane as the sole product. Draw structures of the possible intermediates, and then explain why only a single product is formed in this reaction.

A reaction shows  3-methylcyclohexene reacting with hydrogen bromide to form two cis, trans products. 3-Bromocyclohexene reacting with hydrogen bromide to form a dibromocyclohexane.
Problem 8-68

We’ll see in the next chapter that alkynes undergo many of the same reactions that alkenes do. What product might you expect from each of the following reactions?

A reaction shows 5-methyl-1-hexyne reacting with bromine, hydrogen on palladium-carbon, and hydrogen bromide to yield unknown product(s), depicted by question marks.
Problem 8-69
Hydroxylation of cis-2-butene with OsO4 yields a different product than hydroxylation of trans-2-butene. Draw the structure, show the stereochemistry of each product, and explain the difference between them.
Problem 8-70
Compound A, C11H16O, was found to be an optically active alcohol. Despite its apparent unsaturation, no hydrogen was absorbed on catalytic reduction over a palladium catalyst. On treatment of A with dilute sulfuric acid, dehydration occurred and an optically inactive alkene B, C11H14, was the major product. Alkene B, on ozonolysis, gave two products. One product was identified as propanal, CH3CH2CHO. Compound C, the other product, was shown to be a ketone, C8H8O. How many degrees of unsaturation does A have? Write the reactions, and identify A, B, and C.
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