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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

11 • Additional Problems

11 • Additional Problems

Visualizing Chemistry

Problem 11-21
Write the product you would expect from reaction of each of the following alkyl halides with (1) Na+ SCH3 and (2) Na+ –OH (green = Cl):
(a)
A ball-and-stick model of an alkyl halide comprising a two-carbon chain. The gray, black, and green spheres represent hydrogen, carbon, and chlorine, respectively.
(b)
A ball-and-stick model of an alkyl halide comprising a four-carbon chain. The gray, black, and green spheres represent hydrogen, carbon, and chlorine, respectively.
(c)
A ball-and-stick model of an alkyl halide comprising a six-carbon chain. The gray, black, and green spheres represent hydrogen, carbon, and chlorine, respectively.
Problem 11-22

From what alkyl bromide was the following alkyl acetate made by SN2 reaction? Write the reaction, showing all stereochemistry.

A ball-and-stick model of an alkyl acetate. The gray, black, and red spheres represent hydrogen, carbon, and bromine, respectively.
Problem 11-23

Assign R or S configuration to the following molecule, write the product you would expect from SN2 reaction with NaCN, and assign R or S configuration to the product (green = Cl):

A ball-and-stick model of an alkyl chloride having a double bond. The gray, black, and green spheres represent hydrogen, carbon, and chlorine, respectively.
Problem 11-24

Draw the structure and assign Z or E stereochemistry to the product you expect from E2 reaction of the following molecule with NaOH (green = Cl):

A ball-and-stick model of an alkyl chloride having a cyclohexane ring. The gray, black, green, and red spheres represent hydrogen, carbon, chlorine and bromine, respectively.

Mechanism Problems

Problem 11-25
Predict the product(s) and show the mechanism for each of the following reactions. What do the mechanisms have in common? Why?
(a)
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(b)
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(c)
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(d)
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Problem 11-26
Show the mechanism for each of the following reactions. What do the mechanisms have in common? Why?
(a)
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(b)
3-chloro-1-butene reacts with sodium acetate and acetic acid to form a product in which O C O C H 3 has replaced Cl.
(c)
A three-carbon chain with cyclohexane on C 1 and bromine on C 2 reacts with methanol to produce a three-carbon chain with cyclohexane on C 1and methoxy on C 2.
Problem 11-27
Predict the product(s) for each of the following elimination reactions. In each case show the mechanism. What do the mechanisms have in common? Why?
(a)
An incomplete reaction between 1,1-dimethyl-1-propanol and sulfuric acid to form unknown product(s).
(b)
An incomplete reaction between 3-chloro-1-butene and sodium acetate with acetic acid to form unknown product(s).
(c)
An incomplete reaction between 1S,2S-1,2-dimethylcyclohexanol in sulfuric acid to form unknown product(s).
Problem 11-28
Predict the product(s) for each of the following elimination reactions. In each case show the mechanism. What do the mechanisms have in common? Why?
(a)
An incomplete reaction between 1S,2S-1,2-dimethylcyclohexanol in sulfuric acid to form unknown product(s).
(b)
An incomplete reaction between 1R,2R-1-chloro-2-methylcyclohexane in sodium methoxide and methanol to form unknown product(s).
(c)
An incomplete reaction between 1-bromo-2-methylpropane in potassium t-butoxide and T H F to form unknown product(s).
Problem 11-29
Predict the product(s) for each of the following elimination reactions. In each case show the mechanism. What do the mechanisms have in common? Why?
(a)
An incomplete reaction between the tosylate of 1,2,2-trimethylpropan-1-ol and sodium methoxide in methanol to form unknown product(s).
(b)
An incomplete reaction between 4-hydroxy-2-hexanone and sodium methoxide in methanol to form unknown product(s).
(c)
An incomplete reaction between 3-hydroxy-2-methylcyclohexanone and Na O H in water to form unknown product(s).
Problem 11-30
Predict the product of each of the following reactions, and indicate if the mechanism is likely to be SN1, SN2, E1, E2, or E1cB.
(a)
Alt Text Placeholder
(b)
Alt Text Placeholder
(c)
Alt Text Placeholder
(d)
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Problem 11-31

We saw in Section 8.7 that bromohydrins are converted into epoxides when treated with base. Propose a mechanism, using curved arrows to show the electron flow.

An illustration shows the reaction of a bromohydrin in the presence of NaOH and ethanol to yield epoxide. Bromohydrin shows two carbon atoms single bonded. C1 is single bonded to a hydroxyl group  dash bonded to a hydrogen  and wedge bonded to methyl group. C2 is single bonded to a bromine atom  wedge bonded to a hydrogen  and dash bonded to methyl group. Epoxide shows a 3-membered ring with an oxygen and 2 carbon atoms. Each carbon is dash bonded to a hydrogen and wedge bonded to methyl group.
Problem 11-32

The following tertiary alkyl bromide does not undergo a nucleophilic substitution reaction by either SN1 or SN2 mechanisms. Explain.

The structure of bicyclo[2.2.2]octane with a bromine at a bridgehead carbon.
Problem 11-33

Metabolism of S-adenosylhomocysteine (Section 11.6) involves the following sequence. Propose a mechanism for the second step.

The reaction of S-Adenosylhomocysteine forms an intermediate through the conversion of N A D plus to N A D H, which further reacts with a base to yield homocysteine and another product.
Problem 11-34
Reaction of iodoethane with CN yields a small amount of isonitrile, CH3CH2N C, along with the nitrile CH3CH2C N as the major product. Write electron-dot structures for both products, assign formal charges as necessary, and propose mechanisms to account for their formation.
Problem 11-35

One step in the urea cycle for ridding the body of ammonia is the conversion of argininosuccinate to the amino acid arginine plus fumarate. Propose a mechanism for the reaction, and show the structure of arginine.

The reaction of argininosuccinate in the presence of base forms arginine and fumarate.
Problem 11-36

Methyl esters (RCO2CH3) undergo a cleavage reaction to yield carboxylate ions plus iodomethane on heating with LiI in dimethylformamide:

The reaction of methyl cyclohexanoate with lithium iodide in dimethylformamide forms lithium cyclohexanoate and methyl iodide.

The following evidence has been obtained: (1) The reaction occurs much faster in DMF than in ethanol. (2) The corresponding ethyl ester (RCO2CH2CH3) cleaves approximately 10 times more slowly than the methyl ester. Propose a mechanism for the reaction. What other kinds of experimental evidence could you gather to support your hypothesis?

Problem 11-37

SN2 reactions take place with inversion of configuration, and SN1 reactions take place with racemization. The following substitution reaction, however, occurs with complete retention of configuration. Propose a mechanism. (Hint: two inversions = retention.)

The reaction of (R)-2-bromopropanoic acid first with one percent sodium hydroxide and water, and then with hydronium ion, forms (R)-2-hydroxypropanoic acid.
Problem 11-38

Propose a mechanism for the following reaction, an important step in the laboratory synthesis of proteins:

The reaction of a carbonyl compound in the presence of trifluoroacetic acid yields an alkene and carboxylic acid.

Nucleophilic Substitution Reactions

Problem 11-39
Draw all isomers of C4H9Br, name them, and arrange them in order of decreasing reactivity in the SN2 reaction.
Problem 11-40

The following Walden cycle has been carried out: Explain the results, and indicate where inversion occurs.

Two reactions of a compound with alpha subscript D equals 33. In first and second reactions, compounds with alpha subscript D equal to negative 19.9 and 23.5, respectively, are formed.
Problem 11-41
Which compound in each of the following pairs will react faster in an SN2 reaction with OH?
(a)
CH3Br or CH3I
(b)
CH3CH2I in ethanol or in dimethyl sulfoxide
(c)
(CH3)3CCl or CH3Cl
(d)
H2C = CHBr or H2C = CHCH2Br
Problem 11-42
Which reactant in each of the following pairs is more nucleophilic? Explain.
(a)
NH2 or NH3
(b)
H2O or CH3CO2
(c)
BF3 or F
(d)
(CH3)3P or (CH3)3N
(e)
I or Cl
(f)
C N or OCH3
Problem 11-43
What effect would you expect the following changes to have on the rate of the SN2 reaction of 1-iodo-2-methylbutane with cyanide ion?
(a)
The CN concentration is halved, and the 1-iodo-2-methylbutane concentration is doubled.
(b)
Both the CN and the 1-iodo-2-methylbutane concentrations are tripled.
Problem 11-44
What effect would you expect the following changes to have on the rate of the reaction of ethanol with 2-iodo-2-methylbutane?
(a)
The concentration of the halide is tripled.
(b)
The concentration of the ethanol is halved by adding diethyl ether as an inert solvent.
Problem 11-45
How might you prepare each of the following using a nucleophilic substitution reaction at some step?
(a)
The chemical structure of 4-methyl-2-pentyne.
(b)
The chemical structure of methyl t-butyl ether.
(c)
The chemical structure of pentanenitrile.
(d)
The chemical structure of 1-aminopropane.
Problem 11-46
Which reaction in each of the following pairs would you expect to be faster?
(a)
The SN2 displacement by I on CH3Cl or on CH3OTos
(b)
The SN2 displacement by CH3CO2 on bromoethane or on bromocyclohexane
(c)
The SN2 displacement on 2-bromopropane by CH3CH2O or by CN
(d)
The SN2 displacement by HC C on bromomethane in benzene or in acetonitrile
Problem 11-47
Predict the product and give the stereochemistry resulting from reaction of each of the following nucleophiles with (R)-2-bromooctane:
(a)
CN
(b)
CH3CO2
(c)
CH3S
Problem 11-48
(R)-2-Bromooctane undergoes racemization to give (±)-2-bromooctane when treated with NaBr in dimethyl sulfoxide. Explain.

Elimination Reactions

Problem 11-49
Propose structures for compounds that fit the following descriptions:
(a)
An alkyl halide that gives a mixture of three alkenes on E2 reaction
(b)
An organohalide that will not undergo nucleophilic substitution
(c)
An alkyl halide that gives the non-Zaitsev product on E2 reaction
(d)
An alcohol that reacts rapidly with HCl at 0 °C
Problem 11-50
What products would you expect from the reaction of 1-bromopropane with each of the following?
(a)
NaNH2
(b)
KOC(CH3)3
(c)
NaI
(d)
NaCN
(e)
NaC CH
(f)
Mg, then H2O
Problem 11-51

1-Chloro-1,2-diphenylethane can undergo E2 elimination to give either cis- or trans-1,2-diphenylethylene (stilbene). Draw Newman projections of the reactive conformations leading to both possible products, and suggest a reason why the trans alkene is the major product.

The conversion of 1-chloro-1,2-diphenylethane to trans-1,2-Diphenylethylene in the presence of methoxy ion.
Problem 11-52

Predict the major alkene product of the following E1 reaction:

The reaction of 3-bromo-2,3-dimethylpentane in acetic acid and heat yields an unknown product, depicted by a question mark.
Problem 11-53
There are eight diastereomers of 1,2,3,4,5,6-hexachlorocyclohexane. Draw each in its more stable chair conformation. One isomer loses HCl in an E2 reaction nearly 1000 times more slowly than the others. Which isomer reacts so slowly, and why?

General Problems

Problem 11-54
The following reactions are unlikely to occur as written. Tell what is wrong with each, and predict the actual product.
(a)
The reaction of 2-bromobutane with potassium t-butoxide in t-butanol yields s-butyl t-butyl ether.
(b)
The reaction of fluorocyclohexane with Na O H yields cyclohexanol.
(c)
The reaction of 1-methylcyclohexanol with thionyl chloride and pyridine (a base) yields 1-chloro-1-methylcyclohexane.
Problem 11-55
Arrange the following carbocations in order of increasing stability.
(a)
Three cations of 3-methylcyclopentene. The carbocation is on C 4, the methyl group, and C 5 respectively.
(b)
Three cations of 2-methylpentane. The carbocation is on C 5, C 4, and C 2 respectively.
(c)
Three cations of 3-methyl-1-pentene. The carbocation is on C 3, C 4, and the methyl group respectively.
Problem 11-56
Order each of the following sets of compounds with respect to SN1 reactivity:
(a)
Chemical structures of t-butyl chloride, a benzene ring bonded to a carbon that has a chlorine and two methyl substituents, and 2-aminobutane.
(b)
Chemical structures of t-butyl chloride, t-butyl bromide, and t-butyl alcohol.
(c)
Chemical structures of benzene bonded to methyl bromide, benzene bonded to ethyl bromide ethyl C 1, and carbon bonded to three benzene rings and a bromine.
Problem 11-57
Order each of the following sets of compounds with respect to SN2 reactivity:
(a)
Chemical structures of t-butyl chloride, 1-chloropropane, and 2-chlorobutane.
(b)
Chemical structures of 2-bromo-3-methylbutane, 1-bromo-2-methylpropane, and 1-bromo-2,2-dimethylpropane.
(c)
Condensed formulas of methyl propyl ether, tosylate of 1-propanol, and 1-bromopropane.
Problem 11-58
Predict the major product(s) of each of the following reactions. Identify those reactions where you would expect the product mixture to rotate plane-polarized light.
(a)
An incomplete reaction between the tosylate of cis-4-methyl-1-cyclohexanol and K C N in D M S O to form unknown product(s).
(b)
An incomplete reaction between (S)-2-bromo-2,3-dimethylpentane in sodium methoxide and methanol to form unknown product(s).
(c)
An incomplete reaction between (1S,2S)-1-chloro-1,2-dimethylcyclopentane and methanol to form unknown product(s).
Problem 11-59

Reaction of the following S tosylate with cyanide ion yields a nitrile product that also has S stereochemistry. Explain.

An incomplete reaction between tosylate having S configuration in the presence of sodium cyanide yields an unknown product, depicted by a question mark.
Problem 11-60

Ethers can often be prepared by SN2 reaction of alkoxide ions, RO, with alkyl halides. Suppose you wanted to prepare cyclohexyl methyl ether. Which of the following two possible routes would you choose? Explain.

An illustration shows two reactions that yield cyclohexyl methyl ether as product. In the first reaction  an alkoxide ion reacts with iodomethane. The alkoxide ion shows a cyclo-hexane bonded to an oxygen anion. In the second reaction  iodobenzene reacts with methoxy anion (CH3 O minus). Cyclohexyl methyl ether shows a cyclohexane bonded to a methoxy group.
Problem 11-61

How can you explain the fact that trans-1-bromo-2-methylcyclohexane yields the non-Zaitsev elimination product 3-methylcyclohexene on treatment with base?

A reaction in which trans-1-bromo-2-methylcyclohexane forms 3-methylcyclohexene in the presence of K O H.
Problem 11-62

Predict the product(s) of the following reaction, indicating stereochemistry where necessary:

A reaction of 1-bromo-1,4-dimethylcyclohexane (methy groups are cis to one another) in the presence of water and ethanol yields an unknown product, depicted by a question mark.
Problem 11-63

Alkynes can be made by dehydrohalogenation of vinylic halides in a reaction that is essentially an E2 process. In studying the stereochemistry of this elimination, it was found that (Z)-2-chloro-2-butenedioic acid reacts 50 times as fast as the corresponding E isomer. What conclusion can you draw about the stereochemistry of eliminations in vinylic halides? How does this result compare with eliminations of alkyl halides?

A reaction in which (Z)-2-chloro-2-butenedioic acid forms an alkyne in the presence of sodium amide and hydronium ion.
Problem 11-64
Based on your answer to Problem 11-63, predict the product(s) and show the mechanism for each of the following reactions.
(a)
An incomplete reaction between trans-1-chloro-1-butene first with sodium amide and then with hydronium to form unknown product(s).
(b)
An incomplete reaction between an alkene with bromine (up) and phenyl on the left and methyl (up) and hydrogen on the right, first with sodium amide and then with hydronium.
(c)
An incomplete reaction between cis-1-chloro-1-propene, first with sodium amide and then with hydronium.
Problem 11-65

(S)-2-Butanol slowly racemizes on standing in dilute sulfuric acid. Explain.

The structure of 2-butanol.
Problem 11-66

Reaction of HBr with (R)-3-methyl-3-hexanol leads to racemic 3-bromo-3-methylhexane. Explain.

An illustration shows the structure of 3-Methyl-3-hexanol. A central carbon is bonded to a hydroxyl group at the top  methyl group at the bottom  an ethyl group on the right  and a propyl group on the left.
Problem 11-67

Treatment of 1-bromo-2-deuterio-2-phenylethane with strong base leads to a mixture of deuterated and nondeuterated phenylethylenes in an approximately 7 : 1 ratio. Explain.

A reaction in which 1-bromo-2-deuterio-2-phenylethane reacts with (C H 3)3 C O minus to form deuterated and non deuterated phenylethylene structures.
Problem 11-68
Propose a structure for an alkyl halide that gives only (E)-3-methyl-2-phenyl-2-pentene on E2 elimination. Make sure you indicate the stereochemistry.
Problem 11-69

Although anti periplanar geometry is preferred for E2 reactions, it isn’t absolutely necessary. The following deuterated bromo compound reacts with strong base to yield an undeuterated alkene. A syn elimination has occurred. Make a molecular model of the reactant, and explain the result.

A reaction in which a deuterated bromo compound reacts with a base to form an undeuterated alkene. The double bond in the product is bonded to two hydrogen atoms.
Problem 11-70
The reaction of 1-chlorooctane with CH3CO2 to give octyl acetate is greatly accelerated by adding a small quantity of iodide ion. Explain.
Problem 11-71
Compound X is optically inactive and has the formula C16H16Br2. On treatment with strong base, X gives hydrocarbon Y, C16H14. Compound Y absorbs 2 equivalents of hydrogen when reduced over a palladium catalyst and reacts with ozone to give two fragments. One fragment, Z, is an aldehyde with formula C7H6O. The other fragment is glyoxal, (CHO)2. Write the reactions involved, and suggest structures for X, Y, and Z. What is the stereochemistry of X?
Problem 11-72

When a primary alcohol is treated with p-toluenesulfonyl chloride at room temperature in the presence of an organic base such as pyridine, a tosylate is formed. When the same reaction is carried out at higher temperature, an alkyl chloride is often formed. Explain.

The reaction of benzyl alcohol with tosyl chloride and pyridine at 60 degrees Celsius yields benzyl chloride.
Problem 11-73

The amino acid methionine is formed by a methylation reaction of homocysteine with N-methyltetrahydrofolate. The stereochemistry of the reaction has been probed by carrying out the transformation using a donor with a “chiral methyl group,” which contains protium (H), deuterium (D), and tritium (T) isotopes of hydrogen. Does the methylation reaction occur with inversion or retention of configuration?

The reaction of homocysteine in the presence of methionine synthase forms methionine, N-methyltetrahydrofolate, and Tetrahydrofolate.
Problem 11-74

Amines are converted into alkenes by a two-step process called the Hofmann elimination. SN2 reaction of the amine with an excess of CH3I in the first step yields an intermediate that undergoes E2 reaction when treated with silver oxide as base. Pentylamine, for example, yields 1-pentene. Propose a structure for the intermediate, and explain why it readily undergoes elimination.

A reaction of 1-aminopentane first with excess methyl iodide and then with Ag 2 O and water yields 1-pentene.
Problem 11-75

The antipsychotic drug flupentixol is prepared by the following scheme:

Compound A undergoes a multi-step reaction to produce Flupentixol through the formation of intermediate compounds B, C, D, and E.
(a)
What alkyl chloride B reacts with amine A to form C?
(b)
Compound C is treated with SOCl2, and the product is allowed to react with magnesium metal to give a Grignard reagent D. What is the structure of D?
(c)
We’ll see in Section 19.7 that Grignard reagents add to ketones, such as E, to give tertiary alcohols, such as F. Because of the newly formed chirality center, compound F exists as a pair of enantiomers. Draw both, and assign R,S configurations.
(d)
Two stereoisomers of flupentixol are subsequently formed from F, but only one is shown. Draw the other isomer, and identify the type of stereoisomerism.
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