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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

14 • Additional Problems

14 • Additional Problems

Visualizing Chemistry

Problem 14-16

Show the structures of all possible adducts of the following diene with 1 equivalent of HCl:

The ball-and-stick model has a cyclopentene ring. C 1 is bonded to an ethene group.
Problem 14-17

Show the product of the Diels–Alder reaction of the following diene with 3-buten-2-one,
H2C = CHCOCH3. Make sure you show the full stereochemistry of the reaction product.

The ball-and-stick model has a cyclopentene ring. C 1 of the ring is bonded to C1 of another cyclopentene ring.
Problem 14-18

The following diene does not undergo Diels–Alder reactions. Explain.

The ball-and-stick model has cyclohexene. C 1 is bonded to 3-carbon chain with double bond at C 1. C 2 of ring and chain are each bonded to a methyl group.
Problem 14-19

The following model is that of an allylic carbocation intermediate formed by protonation of a conjugated diene with HBr. Show the structure of the diene and the structures of the final reaction products.

The ball-and-stick model has a 6-carbon chain. C 3 is bonded to a methyl group. Gray and white spheres represent carbon and hydrogen atoms, respectively.

Mechanism Problems

Problem 14-20
Predict the major product(s) from the addition of 1 equivalent of HX and show the mechanism for each of the following reactions.
(a)
A 6-carbon chain with double bonds between C 2-C 3 and C 4-C 5 reacts with hydrogen chloride at 40 degrees Celsius. Product is not shown.
(b)
A 5-carbon chain with double bonds between C 1-C 2 and C 3-C 4, and methyl at C 3 reacts with hydrogen bromide at 40 degrees Celsius. Product is not shown.
(c)
A 4-membered ring with double-bonded methylene groups at C 1 and C 2 reacts with hydrogen chloride at 0 degrees Celsius. Product is not shown.
Problem 14-21

We’ve seen that the Diels–Alder cycloaddition reaction is a one-step, pericyclic process that occurs through a cyclic transition state. Propose a mechanism for the following reaction:

When heated, an 8-membered ring with two double bonds between C 2-C 3 and C 5-C 6 forms benzene and ethene.
Problem 14-22
In light of your answer to Problem 14-21 propose mechanisms for the following reactions.
(a)
When heated, a 6-membered ring made of one oxygen and five carbon atoms with two double bonds and a carbonyl group at position 2 reacts with an alkyne, forming a benzene ring and carbon dioxide..
(b)
A 6-membered ring made of two carbons and four nitrogens (at positions 1, 2, 4, and 5) with alternate double bonds, and with methyl groups at positions 3 and 6 reacts with benzene bonded to ethyne.
Problem 14-23

Luminol, which is used by forensic scientists to find blood, fluoresces as a result of Diels–Alder-like process. The dianion of luminol reacts with O2 to form an unstable peroxide intermediate that then loses nitrogen to form a dicarboxylate and emit light. The process is similar to that in Problems 14-21 and 14-22. Propose a mechanism for this process.

Luminol dianion reacts with molecular oxygen to yield aniline with carboxylate groups bonded at positions 2 and 3. Molecular nitrogen is a byproduct and light is generated.
Problem 14-24

A useful diene in the synthesis of many naturally occurring substances is known as Danishefsky’s diene. It’s useful because after the Diels–Alder reaction it can be converted into a product that can't be accessed by a typical Diels–Alder reaction. Show the Diels–Alder adduct and propose a mechanism that accounts for the final products.

When heated, Danishefsky’s Diene reacts with ethene bound to an aldehyde group to yield Diels–Alder Adduct that reacts with hydrogen chloride to yield three products.

Conjugated Dienes

Problem 14-25
Name the following compounds:
(a)
The condensed structural formula has a 6-carbon chain with double bonds between C 2-C 3 and C 4-C 5. C 3 is single bonded to a methyl group.
(b)
The condensed structural formula has a 7-carbon chain with double bonds between C 1-C 2, C 3-C 4, and C 5-C 6.
(c)
The condensed structural formula has a 7-carbon chain with double bonds between C 2-C 3, C 3-C 4, and C 5-C 6.
(d)
The condensed structural formula has a 5-carbon chain with double bonds between C 1-C 2 and C 3-C 4. C 3 is further single bonded to a 3-carbon chain.
Problem 14-26
Draw and name the six possible diene isomers of formula C5H8. Which of the six are conjugated dienes?
Problem 14-27
What product(s) would you expect to obtain from reaction of 1,3-cyclohexadiene with each of the following?
(a)
1 mol Br2 in CH2Cl2
(b)
O3 followed by Zn
(c)
1 mol HCl in ether
(d)
1 mol DCl in ether
(e)
3-Buten-2-one (H2C = CHCOCH3)
(f)
Excess OsO4, followed by NaHSO3
Problem 14-28

Electrophilic addition of Br2 to isoprene (2-methyl-1,3-butadiene) yields the following product mixture:

Isoprene (2-methyl-1,3-butadiene) reacts with molecular bromine to give three products in 3, 21, and 76 percent yields.

Of the 1,2-addition products, explain why 3,4-dibromo-3-methyl-1-butene (21%) predominates over 3,4-dibromo-2-methyl-1-butene (3%).

Problem 14-29
Propose a structure for a conjugated diene that gives the same product from both 1,2 and 1,4-addition of HBr.
Problem 14-30

Draw the possible products resulting from addition of 1 equivalent of HCl to 1-phenyl-1,3-butadiene. Which would you expect to predominate, and why?

1-Phenyl-1,3-butadiene contains a benzene ring.one carbon of which is bonded to a 4-carbon chain, in which C 1 is double bonded to C 2 and C 3 is double bonded to C 4.

Diels–Alder Reactions

Problem 14-31
Predict the products of the following Diels–Alder reactions:
(a)
Cyclopentadiene reacts with maleic anhydride, a 5-membered ring with four carbons and one oxygen where the carbons either side of the oxygen are carbonyl groups.. Question mark represents the product.
(b)
Cyclohexadiene reacts with a cyclohexadiene with double bonds at C 2 and C 5, and carbonyl groups at C 1 and C 4. Question mark represents the product.
Problem 14-32

2,3-Di-tert-butyl-1,3-butadiene does not undergo Diels–Alder reactions. Explain.

2,3-Di-tert-butyl-1,3-butadiene has a 6-carbon chain with C 3 and C 4 each double bonded to methylene. C 2 and C 5 are each bonded to two methyl groups.
Problem 14-33

Show the structure, including stereochemistry, of the product from the following Diels–Alder reaction:

Benzene bonded to 4-carbon chain containing double bonds at C 1 an C 3  reacts with a four-carbon chain with a double bond between C 2 and C 3 and where C1 and C4 are carbonyl groups also bound to methoxy griups. Question mark represents the product.
Problem 14-34
How can you account for the fact that cis-1,3-pentadiene is much less reactive than trans-1,3-pentadiene in the Diels–Alder reaction?
Problem 14-35
Would you expect a conjugated diyne such as 1,3-butadiyne to undergo Diels–Alder reaction with a dienophile? Explain.
Problem 14-36

Reaction of isoprene (2-methyl-1,3-butadiene) with ethyl propenoate gives a mixture of two Diels–Alder adducts. Show the structure of both, and explain why a mixture is formed.

A 4-carbon chain with  double bonds between C1-C2 and C3-C4 and with a methyl group at C2 reacts with ethyl propenoate.Question mark represents the product.
Problem 14-37

Rank the following dienophiles in order of their expected reactivity in the Diels–Alder reaction.

Ethene with methyl at C 1, ethene with aldehyde at C 1, ethene with both carbons each bonded to two cyano groups, and ethene with both carbons each bonded to two methyl groups.
Problem 14-38
1,3-Cyclopentadiene is very reactive in Diels–Alder cycloaddition reactions, but 1,3-cyclohexadiene is less reactive and 1,3-cycloheptadiene is nearly inert. Explain. (Molecular models are helpful.)
Problem 14-39

1,3-Pentadiene is much more reactive in Diels–Alder reactions than 2,4-pentadienal. Why might this be?

1,3-pentadiene has a 5-carbon chain with doiuble bonds between C1-C2 and C3-C4. 2,4-Pentadienal has a 5-carbon chain with doiuble bonds between C2-C3 and C4-C5 and a carbonyl group at C1
Problem 14-40
How could you use Diels–Alder reactions to prepare the following products? Show the starting diene and dienophile in each case.
(a)
A cyclohexene ring is fused to a 5-membered ring made of four carbon atoms and an oxygen atom at postion 3. Carbonds at positions 2 and 5 of the ring are carbonyls..
(b)
A 7-membered bicyclic ring. C 2 is double bonded to C 3. C 6 is bonded to a hydrogen atom and a cyano group.
(c)
Cyclohexene fused to a cyclohexane where C 1 and C 4 are carbonyls. The cyclohexane is further fused to another cyclohexene.
(d)
Cyclohexadiene ring with double bonds between C1-C2 and C4-C5. C 1 is bonded to C O 2 C H 3 group.
Problem 14-41

Show the product of the following reaction.

Cyclobutene with double bonded oxygen at C 3 reacts in the presence of zinc chloride with a 6-carbon chain that has double bonds between C 2-C 3 and C 4-C 5 .

Diene Polymers

Problem 14-42
Tires whose sidewalls are made of natural rubber tend to crack and weather rapidly in areas around cities where high levels of ozone and other industrial pollutants are found. Explain.
Problem 14-43
1,3-Cyclopentadiene polymerizes slowly at room temperature to yield a polymer that has no double bonds except on the ends. On heating, the polymer breaks down to regenerate 1,3-cyclopentadiene. Propose a structure for the product.

UV Spectroscopy

Problem 14-44
Arrange the molecules in each of the following sets according to where you would expect to find their wavelength of maximum absorption in UV spectroscopy, from shortest to longest wavelength.
(a)
Three cyclohexadienes fused to cyclohexenes. First 1,4,5,8-tetrahydronaphthalene. Second 1,6-dihydronaphthalene. Third 1,2,5,6-eetrahydronaphthaline.
(b)
Three 1,3-cyclohexadiene rings. First: with methylene groups at C 5 and C 6. Second: with methyl groups at C 5 and C 6. Third: with a methylene group at C 5 and a methyl group at C 6.
(c)
Three structures with a benzene ring at the end of a 5-carbon chain. First: Double bonds at C 1 and C 4 of the chain. Second: Double bonds at C 1 and C 3 of the chain. Third: Double bonds at C 2 and C 4 of the chain.
Problem 14-45
Which of the following compounds would you expect to have a π ​→ ​π* UV absorption in the 200 to 400 nm range?
(a)
The structure has a cyclopentene ring. C 4 is double bonded to a methylene group.
(b)
Pyridine has a 6-membered ring with nitrogen in the first position. The ring has alternate double bonds.
(c)
The condensed structural formula of a ketene reads, (C H 3) 2 C double bonded to C double bonded to O.
Problem 14-46
Would you expect allene, H2C = C = CH2, to show a UV absorption in the 200 to 400 nm range? Explain.
Problem 14-47

The following ultraviolet absorption maxima have been measured:

1,3-Butadiene 217 nm
2-Methyl-1,3-butadiene 220 nm
1,3-Pentadiene 223 nm
2,3-Dimethyl-1,3-butadiene 226 nm
2,4-Hexadiene 227 nm
2,4-Dimethyl-1,3-pentadiene 232 nm
2,5-Dimethyl-2,4-hexadiene 240 nm

What conclusion can you draw about the effect of alkyl substitution on UV absorption maxima? Approximately what effect does each added alkyl group have?

Problem 14-48
1,3,5-Hexatriene has λmax = 258 nm. In light of your answer to Problem 14-47, approximately where would you expect 2,3-dimethyl-1,3,5-hexatriene to absorb?
Problem 14-49

β-Ocimene is a pleasant-smelling hydrocarbon found in the leaves of certain herbs. It has the molecular formula C10H16 and a UV absorption maximum at 232 nm. On hydrogenation with a palladium catalyst, 2,6-dimethyloctane is obtained. Ozonolysis of β-ocimene, followed by treatment with zinc and acetic acid, produces the following four fragments:

The structures of acetone, formaldehyde, pyruvaldehyde, and malonaldehyde.
(a)
How many double bonds does β-ocimene have?
(b)
Is β-ocimene conjugated or nonconjugated?
(c)
Propose a structure for β-ocimene.
(d)
Write the reactions, showing starting material and products.

General Problems

Problem 14-50
Draw the resonance forms that result when the following dienes are protonated. If the resonance forms differ in energy, identify the most stable one.
(a)
The structure has a 6-carbon chain with double bonds between C 2-C 3 and C 4-C 5.
(b)
The structure has a cyclohexadiene ring with double bonds between C 1-C 2 and C 3-C 4. C 1 and C 4 are each bonded to a methyl group.
(c)
The structure has a cyclopentadiene ring with double bonds between C 1-C 2 and C 3-C 4. C 2 and C 3 are each bonded to a methyl group.
Problem 14-51
Answer the following questions for 1,3,5-cycloheptatriene.
(a)
How many p atomic orbitals are in the conjugated system?
(b)
How many molecular orbitals describe the conjugated system?
(c)
How many molecular orbitals are bonding molecular orbitals?
(d)
How many molecular orbitals are anti-bonding molecular orbitals?
(e)
Which molecular orbitals are filled with electrons?
(f)
If this molecule were to absorb a photon of UV light an electron would move between which two molecular orbitals (be specific)?
Problem 14-52
Treatment of 3,4-dibromohexane with strong base leads to loss of 2 equivalents of HBr and formation of a product with formula C6H10. Three products are possible. Name each of the three, and tell how you would use 1H and 13C NMR spectroscopy to help identify them. How would you use UV spectroscopy?
Problem 14-53

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

A cyclohexene with a double bond between C1-C2 and a methoxy group at C1 reacts with hydrogen chloride to form a cyclohexane ring, in which C 1 is bonded to a methoxy group and a chlorine atom.
Problem 14-54

Aldrin, a chlorinated insecticide now banned from use in most countries since 1990, can be made by Diels–Alder reaction of hexachloro-1,3-cyclopentadiene with norbornadiene. What is the structure of aldrin?

The structure of norbornadiene has a 7-membered bicyclic ring with two double bonds.
Problem 14-55
Norbornadiene (Problem 14-54) can be prepared by reaction of chloroethylene with 1,3-cyclopentadiene, followed by treatment of the product with sodium ethoxide. Write the overall scheme, and identify the two kinds of reactions.
Problem 14-56

The triene shown here reacts with 2 equivalents of maleic anhydride to yield a product with the formula C17H16O6. Predict a structure for the product.

A cyclohexene with an ethene group at C 2 and a  methylene at C 3 reacts with 2 equivalents of maleic anhydride to form C 17 H 16 O 6.
Problem 14-57

Myrcene, C10H16, is found in oil of bay leaves and is isomeric with β-ocimene (Problem 14-49). It has an ultraviolet absorption at 226 nm and can be hydrogenated to yield 2,6-dimethyloctane. On ozonolysis followed by zinc/acetic acid treatment, myrcene yields formaldehyde, acetone, and 2-oxopentanedial:

The condensed structure of 2-oxopentanedial has a 5-carbon chain. C 1, C 2, and C 5 are each double-bonded to an oxygen atom.

Propose a structure for myrcene, and write the reactions, showing starting material and products.

Problem 14-58

Hydrocarbon A, C10H14, has a UV absorption at λmax = 236 nm and gives hydrocarbon B, C10H18, on hydrogenation. Ozonolysis of A, followed by zinc/acetic acid treatment, yields the following diketo dialdehyde:

The condensed formula of compound has a 10-carbon chain. C 1, C 5, C 6, and C 10 are all double-bonded to oxygen atoms.

An illustration shows the structure of diketo dialdehyde. It shows two carbonyl groups single bonded to each other. Each carbonyl group is bonded to a chain of three methylene groups and then to an aldehyde group.

(a)
Propose two possible structures for A.
(b)
Hydrocarbon A reacts with maleic anhydride to yield a Diels–Alder adduct. Which of your structures for A is correct?
(c)
Write the reactions, showing the starting material and products.
Problem 14-59

Adiponitrile, a starting material used in the manufacture of nylon, can be prepared in three steps from 1,3-butadiene. How would you carry out this synthesis?

A 3-step reaction shows the formation of adiponitrile from 1,3-butadiene
Problem 14-60

Ergosterol, a precursor of vitamin D, has λmax = 282 nm and molar absorptivity ϵ = 11,900. What is the concentration of ergosterol in a solution whose absorbance A = 0.065 with a sample pathlength l = 1.00 cm?

The wedge-dash structure of ergosterol that has the chemical formula C 28 H 44 O.
Problem 14-61

Dimethyl butynedioate undergoes a Diels–Alder reaction with (2E,4E)-2,4-hexadiene. Show the structure and stereochemistry of the product.

The condensed formula of compound has a 4-carbon chain. C 2 is triple-bonded to C3. C1 and C4 are carbonyl groups each bonded to methoxy groups, C 5, C 6, and C 10 are all double-bonded to oxygen atoms.
Problem 14-62
Dimethyl butynedioate also undergoes a Diels–Alder reaction with (2E,4Z)-2,4-hexadiene, but the stereochemistry of the product is different from that of the (2E,4E) isomer (Problem 14-61). Explain.
Problem 14-63

How would you carry out the following synthesis (more than one step is required)? What stereochemical relationship between the –CO2CH3 group attached to the cyclohexane ring and the –CHO groups would your synthesis produce?

1,3-Cyclohexadiene reacts with ethene bonded to C O 2 C H 3 in the presence of an unknown reagent represented by a question mark to form a substituted product.
Problem 14-64

The double bond of an enamine (alkene + amine) is much more nucleophilic than a typical alkene double bond. Assuming that the nitrogen atom in an enamine is sp2-hybridized, draw an orbital picture of an enamine, and explain why the double bond is electron-rich.

An enamine comprises of a 2-carbon chain with a double bond between. C 1 and C 2 and a nitrogen with two R groups and a lone pair is attached to C 2.
Problem 14-65

Benzene has an ultraviolet absorption at λmax = 204 nm, and para-toluidine has λmax = 235 nm. How do you account for this difference?

The structures of benzene and para-toluidine with lambda max values of 204 and 235 nanometers, respectively.
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