Electron Flow in Organic Chemistry: A Decision-Based Guide to Organic Mechanisms

Teaches students to solve problems in Organic Chemistry using methods of analysis that are valuable and portable to other fields. Electron Flow in Organic Chemistry provides a unique decision-based approach that develops a chemical intuition based on a crosschecked analysis process. Assuming only a general background in chemistry, this acclaimed textbook teaches students how to write reasonable reaction mechanisms and use analytical tools to solve both simple and complex problems in organic chemistry. As in previous editions, the author breaks down challenging organic mechanisms into a limited number of core elemental mechanistic processes, the electron flow pathways, to explain all organic reactions―using flow charts as decision maps, energy surfaces as problem space maps, and correlation matrices to display all possible interactions. The third edition features entirely new chapters on crosschecking chemical reactions through good mechanistic thinking and solving spectral analysis problems using organic structure elucidation strategies. This edition also includes more biochemical reaction mechanism examples, additional exercises with answers, expanded discussion of how general chemistry concepts can show that structure determines reactivity, and new appendix covering transition metal organometallics. Emphasizing critical thinking rather than memorization to solve mechanistic problems, this popular textbook: Features new and expanded material throughout, including more flowcharts, correlation matrices, energy surfaces, and algorithms that illustrate key decision-making processes. Provides examples from the field of biochemistry of relevance to students in chemistry, biology, and medicine. Incorporates principles from computer science and artificial intelligence to teach decision-making processes. Contains a general bibliography, quick-reference charts and tables, pathway summaries, a major decisions guide, and other helpful tools. Offers material for instructors including a solutions manual, supplemental exercises with detailed answers for each chapter usable as an exam file, and additional online resources. Electron Flow in Organic Chemistry: A Decision-Based Guide to Organic Mechanisms, Third Edition, is the perfect primary textbook for advanced undergraduate or beginning graduate courses in organic reaction mechanisms, and an excellent supplement for graduate courses in physical organic chemistry, enzymatic reaction mechanisms, and biochemistry. Cover Half Title Electron Flow in Organic Chemistry: A Decision-Based Guide to Organic Mechanisms Copyright Contents in Brief Contents Preface 1. Bonding and Electron Distribution 1.1 The Decision-Based Approach to Organic Chemistry 1.1.1 Introduction to Problem Spaces 1.1.2 Introduction to Tree Searches 1.1.3 Introduction to Control Knowledge 1.1.4 Preview of the Goals of Beginning Chapters 1.1.5 The Principle of Electron Flow 1.2 Ionin and Covalent Bonding 1.3 Lewis Structures and Resonance Forms 1.3.1 Procedure for Drawing Lewis Structures 1.3.2 Resonance Hybrids 1.4 Curved-Arrow Notation 1.4.1 Good Arrow Pushing Habits 1.4.2 Common Errors 1.5 Nomenclature and Abbreviations 1.5.1 Common Abbreviations 1.5.2 Line Structure 1.5.3 List of the First 10 Alkanes 1.6 The Shapes of Molecules 1.7 An Orbital View of Bonding 1.7.1 Review of Orbitals Used in Bonding 1.7.2 Using p Orbitals to Make the Sigma and Pi Bonds of Nitrogen 1.7.3 Hybridization 1.7.4 Single Bonds 1.7.5 Double Bonds 1.7.6 Triple Bonds 1.7.7 Cumulenes 1.8 Molecular Repulsions, Attractions, and Hydrogen Bonding 1.8.1 Nonbonded Repulsions 1.8.2 Dipole Attractions and Repulsions 1.8.3 Hydrogen Bonding 1.8.4 Cation–Pi Interactions 1.9 Conjugation, Vinylogy, and Aromaticity 1.9.1 Conjugation 1.9.2 Vinylogy 1.9.3 Aromaticity 1.10 Summary 2. The Process of Bond Formation 2.1 Energetics Control Knowledge 2.2 Orbital Overlap in Covalent Bond Formation 2.2.1 Sigma Bonding 2.2.2 Pi Bonding 2.2.3 Microscopic Reversibility 2.3 The Isomer Family Tree 2.4 Polarizability and Hard and Soft Acid–Base Theory 2.5 Thermodynamics, Position of Equilibrium 2.5.1 Energy Surfaces Give an Overview 2.5.2 The Equilibrium Constant is Determined by ΔG° 2.6 Kinetics, Rate of Reaction 2.6.1 Barrier Height, ΔG‡, Determines Reaction Rate 2.6.2 The Basics of Barriers 2.6.3 Mathematical Perspective on Kinetics 2.7 Solvent Stabilization of Ions 2.8 Enzymatic Catalysis—Lessons from Biochemistry 2.8.1 Collision Frequency 2.8.2 Enzyme Active Sites 2.8.3 Enzymes Bind the Transition State Best 2.9 Summary 3. Proton Transfer and the Principles of Stability 3.1 Introduction to Proton Transfer 3.1.1 Acid and Base Generic Groups and the Proton-Transfer Path 3.2 Ranking of Acids and Bases, The pKa Chart 3.2.1 The pKa Chart and pH Relationships 3.2.2 Media pH Cross-check 3.2.3 Common Acids and Their pKa Values 3.2.4 Common Bases and Their pKabH Values 3.3 Structural Factors that Influence Acid Strength 3.3.1 Electronegativity 3.3.2 Strength of the Bond to H 3.3.3 Resonance Effects 3.3.4 Inductive/Field Effects 3.3.5 Hydrogen Bonding 3.3.6 Aromaticity 3.3.7 Charge 3.3.8 Extrinsic Factors—Solvation and Ion Pairing 3.3.9 Super Acid Systems 3.4 Structural Factors that Influence Base Strength 3.4.1 Anions are More Basic Than the Corresponding Neutral Species 3.4.2 Lone Pairs with Less s Character are More Basic 3.4.3 Lone Pairs on Less Electronegative Atoms are More Basic 3.4.4 Conjugated Systems Preserve Conjugation If At All Possible 3.4.5 Inductive/Field Effects Affect the Stability of Conjugate Acids 3.4.6 Resonance Effects Affect the Stability of Conjugate Acids 3.5 Carbon Acids and Ranking of Electron-Withdrawing Groups 3.5.1 Ranking of Electron-Withdrawing Groups 3.5.2 Carbanion Stability Trends 3.5.3 Estimation of the pKa for Related Compounds 3.5.4 Finding the Most Acidic Hydrogen 3.6 Calculation of Keq for Proton Transfer 3.7 Proton-Transfer Mechanisms 3.7.1 Problem Space for Proton-Transfer Mechanisms 3.7.2 Make Conscious Decisions 3.7.3 What Happened?—Mapping Changes 3.7.4 Pruning the Tree—Cross-checks 3.7.5 Example Proton-Transfer Mechanism 3.8 Common Errors 3.8.1 Failure to Stay on the Path 3.8.2 Failure to Check Keq 3.8.3 Media pH Errors 3.8.4 pKa Span Errors 3.8.5 Drop-off H+ Only Shorthand Notation 3.8.6 Wrong pKa Errors 3.8.7 Strained Intramolecular Proton-Transfer Errors 3.9 Proton-Transfer Product Predictions 3.10 Proton-Transfer Summary 4. Important Reaction Archetypes 4.1 Introduction to Reaction Archetypes 4.2 Nucleophilic Substitution at a Tetrahedral Center 4.2.1 Substitution Electron Flow Paths 4.2.2 Ranking of Nucleophiles 4.2.3 Ranking of Leaving Groups 4.2.4 Carbocation Stability Trends 4.2.5 Ranking of Electron-Releasing Groups 4.2.6 Stereochemistry of Substitution Reactions 4.2.7 SN2 Electron Flow Pathway 4.2.8 SN1 Reaction: Electron Flow Pathways DN + AN 4.2.9 Ionization of Leaving Groups 4.2.10 SN1/SN2 Substitution Spectrum 4.2.11 Substitution via a Pentacovalent Intermediate 4.2.12 Approaches to Substitution Mechanisms 4.2.13 Substitution Summary 4.3 Elimination Reactions Create pi Bonds 4.3.1 Elimination Electron Flow Paths 4.3.2 The E1 Reaction: Electron Flow Pathways DN + DE 4.3.3 The E2 Electron Flow Pathway 4.3.4 The E1cB Reaction: Electron Flow Pathways p.t. + Eβ 4.3.5 The E1/E2/E1cB Elimination Spectrum 4.3.6 Eliminations in Cyclic Systems 4.3.7 Eliminations That Yield Carbonyls 4.3.8 Approaches to Elimination Mechanisms 4.3.9 Elimination Summary 4.4 Addition Reactions to Polarized Multiple Bonds 4.4.1 Introduction to Addition Reactions 4.4.2 Addition Electron Flow Paths 4.4.3 The AdE2 Reaction: Electron Flow Pathways AE + AN 4.4.4 The AdE3 Electron Flow Pathway 4.4.5 The AdN2 Reaction: Electron Flow Pathways AdN + p.t. 4.4.6 The AdE2/AdE3/AdN2 Addition Spectrum 4.4.7 Additions to Carbonyls 4.4.8 Approaches to Addition Mechanisms 4.4.9 Addition Summary 4.5 Nucleophilic Substitution at a Trigonal Planar Center 4.5.1 Addition–Elimination Electron Flow Paths 4.5.2 Drawing Energy Diagrams 4.5.3 The Amazingly Useful pKa Chart 4.5.4 Approaches to Addition–Elimination Mechanisms 4.5.5 Addition–Elimination Summary 4.6 Electrophilic Substitution at a Trigonal Planar Center 4.6.1 Electrophilic Aromatic Substitution 4.6.2 Approaches to Electrophilic Aromatic Substitution Mechanisms 4.6.3 Electrophilic Aromatic Substitution Summary 4.7 Rearrangements to an Electrophilic Carbon 4.7.1 Introduction to Rearrangement Reactions 4.7.2 Rearrangement Electron Flow Paths 4.7.3 Approaches to Rearrangement Mechanisms 4.7.4 Rearrangement Summary 4.8 Reaction Archetype Summary 5. Classification of Electron Sources 5.1 Generalized Ranking of Electron Sources 5.2 Nonbonding Electrons 5.2.1 Lone Pairs as Brønsted–Lowry Bases 5.2.2 Heteroatom Lone Pairs as Nucleophiles 5.2.3 Easily Oxidizable Metals 5.3 Electron-Rich Sigma Bonds 5.3.1 Organometallics 5.3.2 Group 1A Metal Hydrides 5.3.3 Complex Metal Hydrides 5.4 Electron-Rich pi Bonds 5.4.1 Allylic Sources 5.4.2 Allylic Alkyne Sources 5.5 Simple pi Bonds 5.5.1 Alkene Sources 5.5.2 Diene Sources 5.5.3 Alkyne Sources 5.5.4 Allene (Cumulene) Sources 5.6 Aromatic Rings 5.7 Summary of Generic Electron Sources 5.7.1 Generic Electron Source Table 5.7.2 Generic Electron Source Classification Flowchart 5.7.3 Common Sources Reactivity Summary 6. Classification of Electron Sinks 6.1 Generalized Ranking of Electron Sinks 6.2 Electron-Deficient Species 6.2.1 Carbocations 6.2.2 Inorganic Lewis Acids 6.2.3 Metal Ions M2+ 6.2.4 Metal Ions as Oxidants Mn7+ and Cr6+ 6.3 Weak Single Bonds 6.3.1 Acids 6.3.2 Leaving Groups on Heteroatoms 6.3.3 Leaving Group Bound to an sp3-Hybridized Carbon 6.4 Polarized Multiple Bonds without Leaving Groups 6.4.1 Heteroatom–Carbon Double Bonds 6.4.2 Heteroatom–Carbon Triple Bonds 6.4.3 Heterocumulenes 6.4.4 Conjugate Acceptors 6.4.5 Triply Bonded and Allenic Conjugate Acceptors 6.5 Polarized Multiple Bonds with Leaving Groups 6.5.1 Carboxyl Derivatives, L–C=Y 6.5.2 Vinyl Leaving Groups 6.5.3 Leaving Groups on Polarized Triple Bonds 6.6 Summary of Generic Electron Sinks 6.6.1 Reactivity Comparison Between Various Classes 6.6.2 Generic Electron Sink Table 6.6.3 Generic Electron Sink Classification Flowchart 6.6.4 Common Sinks Reactivity Summary 7. The Electron Flow Pathways 7.1 The Dozen Most Common Pathways 7.1.1 Path p.t., Proton Transfer to a Lone Pair 7.1.2 Path DN, Ionization of a Leaving Group 7.1.3 Path AN, Trapping of an Electron-Deficient Species 7.1.4 Path AE, Electrophile Addition to a Multiple Bond 7.1.5 Path DE, Electrofuge Loss from a Cation To Form a Pi Bond 7.1.6 Path SN2, The SN2 Substitution 7.1.7 Path E2, The E2 Elimination 7.1.8 Path AdE3, The AdE3 Addition 7.1.9 Path AdN, Nucleophilic Addition to a Polarized Multiple Bond 7.1.10 Path Eβ, Beta Elimination from an Anion or Lone Pair 7.1.11 Path 1,2R, 1,2 Rearrangement of a Carbocation 7.1.12 Path 1,2RL, 1,2 Rearrangement with Loss of Leaving Group 7.2 Six Minor Pathways 7.2.1 Path pent., Substitution via a Pentacovalent Intermediate 7.2.2 Path 6e, Concerted Six-Electron Pericyclic Reactions 7.2.3 Path Ei, Thermal Internal Syn Elimination 7.2.4 Path NuL, Nu–L Additions (Three-membered ring formation) 7.2.5 Path 4e, Four-Center, Four-Electron 7.2.6 Path H− t., Hydride Transfer to a Cationic Center 7.3 Common Path Combinations 7.3.1 SN1 (Substitution, Nucleophilic, Unimolecular), DN + AN 7.3.2 AdE2 (Addition, Electrophilic, Bimolecular), AE + AN 7.3.3 E1 (Elimination, Unimolecular), DN + DE 7.3.4 SE2Ar Electrophilic Aromatic Substitution, AE + DE 7.3.5 E1cB (Elimination, Unimolecular, Conjugate Base), p.t. + Eβ 7.3.6 AdN2 (Addition, Nucleophilic, Bimolecular), AdN + p.t. 7.3.7 Addition–Elimination, AdN + Eβ 7.3.8 Tautomerization, taut. 7.4 Variations on a Theme 7.4.1 Atom Variations 7.4.2 Vinylogous Variations 7.4.3 Extent of Proton Transfer Variations 7.5 Twelve Major Paths Summary and Cross-Checks 7.6 Six Minor Paths Summary 7.7 Common Path Combinations Summary 8. Interaction of Electron Sources and Sinks 8.1 Source and Sink Correlation Matrix 8.2 H–A Sinks Reacting with Common Sources 8.2.1 Lone Pair Sources Reacting with Acids 8.2.2 Bases Reacting with Acids Having an Adjacent CH 8.2.3 Complex Metal Hydrides Reacting with Acids 8.2.4 Organometallics Reacting with Acids 8.2.5 Allylic Sources Reacting with Acids 8.2.6 Simple Pi Bonds Reacting with Acids 8.2.7 Aromatics Reacting with Acids 8.3 Y–L Sinks Reacting with Common Sources 8.3.1 Lone Pair Sources Reacting with Y–L 8.3.2 Bases Reacting with Y–L Having an Adjacent CH, Oxidations 8.3.3 Complex Metal Hydrides Reacting with Y–L 8.3.4 Organometallics Reacting with Y–L 8.3.5 Allylic Sources Reacting with Y–L 8.3.6 Simple Pi Sources Reacting with Y–L 8.3.7 Aromatic Sources Reacting with Y–L 8.4 sp3 C–L Sinks Reacting with Common Sources 8.4.1 Lone Pair Sources Reacting with sp3 C–L 8.4.2 Bases Reacting with sp3 C–L Having an Adjacent CH, Eliminations 8.4.3 Complex Metal Hydrides Reacting with sp3 C–L 8.4.4 Organometallics Reacting with sp3 C–L 8.4.5 Allylic Sources Reacting with sp3 C–L 8.4.6 Simple Pi Sources Reacting with sp3 C–L 8.4.7 Aromatic Sources Reacting with sp3 C–L 8.5 C=Y Sinks Reacting with Common Sources 8.5.1 Lone Pair Sources Reacting with C=Y 8.5.2 Bases Reacting with C=Y Having an Adjacent CH, Enolates 8.5.3 Complex Metal Hydrides Reacting with C=Y 8.5.4 Organometallics Reacting with C=Y 8.5.5 Allylic Sources Reacting with C=Y 8.5.6 Simple Pi Bond Sources Reacting with C=Y 8.5.7 Aromatic Sources Reacting with C=Y 8.6 R–C≡Y Sinks Reacting with Common Sources 8.6.1 Lone Pair Sources Reacting with R–C≡N 8.6.2 Bases Reacting with R–C≡N Having an Adjacent CH, NitrileEnolates 8.6.3 Complex Metal Hydrides Reacting with R–C≡N 8.6.4 Organometallics Reacting with R–C≡N 8.6.5 Allylic Sources Reacting with R–C≡N 8.6.6 Simple Pi Bond Sources Reacting with R–C≡N 8.6.7 Aromatic Sources Reacting with R–C≡N 8.7 C=C–EWG Sinks Reacting with Common Sources 8.7.1 Conjugate Addition by Lone Pair Sources to C=C–EWG 8.7.2 Bases Reacting with C=C–EWG Having an Adjacent CH, ExtendedEnolates 8.7.3 Conjugate Addition by Complex Metal Hydrides to C=C–EWG 8.7.4 Conjugate Addition by Organometallics to C=C–EWG 8.7.5 Conjugate Addition by Allylic Sources to C=C–EWG 8.7.6 Conjugate Addition by Simple Pi Sources to C=C–EWG 8.7.7 Conjugate Addition by Aromatic Sources to C=C–EWG 8.8 L–C=Y Sinks Reacting with Common Sources 8.8.1 Lone Pair Sources Reacting with L–C=Y 8.8.2 Bases Reacting with L–C=Y Sinks Having an Adjacent CH,Enolization 8.8.3 Metal Hydrides Reacting with L–C=Y 8.8.4 Organometallic Sources Reacting with L–C=Y Sinks 8.8.5 Allylic Sources Reacting with L–C=Y Sinks, Acylation 8.8.6 Simple Pi Bond Sources Reacting with L–C=Y Sinks 8.8.7 Aromatic Sources Reacting with L–C=Y Sinks 8.9 Miscellaneous Reactions 8.9.1 Electron-Deficient Species as Electron Sinks 8.9.2 Carbonate Derivatives as Electron Sinks 8.9.3 Heterocumulenes as Electron Sinks 8.9.4 Nucleophilic Aromatic Substitution 8.10 Metal Ions as Electron Sinks 8.10.1 Metal Ions as Electrophiles and Electrophilic Catalysts 8.10.2 Metal Ions as Oxidants 8.10.3 Hydrogenation via Transition Metal Catalysts 8.11 Rearrangements to an Electrophilic Center 8.12 Nu–L Reactions 8.12.1 Nu–L Reacting with Trialkylboranes 8.12.2 Nu–L Reacting with Acids 8.12.3 Nu–L Reacting with sp3 C–L 8.12.4 Nu–L Reacting with C=C 8.12.5 Nu–L Reacting with C=Y 8.12.6 Nu–L Reacting with C=C–EWG 8.12.7 Nu–L Reacting with L–C=O 8.12.8 Thiamine-Catalyzed Decarboxylation of Pyruvate 8.13 Product Matrix Summary 9. Decisions, Decisions 9.1 Decision Point Recognition 9.2 Multiple Additions 9.2.1 Nucleophilic Addition to L–C=O 9.2.2 Additions of Nucleophiles to Nitriles 9.3 Regiochemistry and Stereochemistry of Enolateformation 9.4 Ambident Nucleophiles C=C–Z: 9.4.1 Alkylation of Enols, Enolates, and Enamines with sp3 C–L 9.4.2 Reaction of Enols and Enolates with Y–L 9.4.3 Acylation of Enols, Enolates, and Enamines with O=C–L 9.4.4 Amides and Amidates 9.5 Substitution vs. Elimination 9.5.1 Substitution vs. Elimination Energy Surface and Variables 9.5.2 SN1 vs. E1 Competition 9.5.3 SN2 vs. E2 Competition 9.5.4 3D Correlation Matrix for Substitution vs. Elimination 9.6 Ambident Electrophiles C=C–EWG 9.6.1 Conjugated Ketone Systems—Enones 9.6.2 Miscellaneous Ambident Electrophiles 9.7 Intermolecular vs. Intramolecular 9.8 To Migrate or not to an Electrophilic Center 9.9 Summary 10. Choosing the Most Probable Path 10.1 Problem-Solving in General 10.1.1 Study The Material Before Attempting The Problems 10.1.2 Establish An Informational Hierarchy While You Study 10.1.3 Gather A Collection Of Commonly Needed Problem-Solving tools 10.1.4 Read The Problem Carefully—Understand The Problem 10.1.5 Map Changes—Understand Bonds Made And Broken 10.1.6 Do Not Ignore What You Do Not Understand 10.1.7 Gather All Applicable Information About The Problem First 10.1.8 Classify Into Generic Groupings 10.1.9 Recognize Possible Intermediate Goals 10.1.10 Always Write Down Any Possibility That You Consider 10.1.11 Have A Systematic Method To Your Answer Search 10.1.12 Look For Alternatives—Generate All Paths, Then Select TheBest 10.1.13 Recognize The Generic Form Of Each Step 10.1.14 Work Carefully And Cross-check The Work As You Go 10.1.15 Don't Skip Steps—Look For Any Hidden Decision Points 10.1.16 Make A Scratch Sheet Into An Idea Map 10.1.17 Beware Of Memorization 10.1.18 Watch For Bad Habits 10.1.19 Stay On The Pathways 10.1.20 Don't Force The Answer! 10.1.21 If Stuck, Don't Just Stare At The Page, Draw Something On It! 10.1.22 Recognize The Limits Placed By The Reaction Conditions 10.1.23 Beware Of Limits That You Place On The Problem 10.1.24 If Stuck, Examine The Other Possibilities At Each Decision Point 10.1.25 When Done, Always Go Back And Check The Answer 10.1.26 Practice, Practice, Practice 10.1.27 What Can Be Learned From The Methods You Used To SolveThe Problem That Would Be Applicable To Other Problems? 10.2 General Mechanistic Cross-Checks 10.2.1 Electron Flow Pathway Check 10.2.2 Completeness Check 10.2.3 Media Check 10.2.4 Energetics and Stability Check 10.2.5 Charge and Typo Check 10.3 The Path-Selection Process 10.3.1 Understand the System 10.3.2 Find Possible Alternatives 10.3.3 Evaluate and Cross-check 10.3.4 Repeat The Process 10.4 Reaction Mechanism Strategies 10.5 Worked Mechanism Examples 10.5.1 Alkyne Hydrobromination 10.5.2 Imine Formation 10.5.3 Aldol Condensation 10.5.4 Electrophilic Aromatic Substitution 10.5.5 Glucose to Fructose 10.6 Product Prediction Strategies 10.6.1 Understand the System 10.6.2 Find Possible Routes 10.6.3 Evaluate and Cross-Check 10.7 Worked Product Prediction Examples 10.7.1 Predict the Product of Reaction of Ethyl Acetoacetate, Ethoxide,and 1-Bromobutane 10.7.2 Predict the Product of Reaction of an Ester and Ethoxide 10.7.3 Predict the Product of Reaction of a Ketal and Acidic Water 10.7.4 Predict the Product of Reaction of an Amide and Basic Water 10.7.5 Predict the Product of Reaction of a Carboxylic Acid and SOCl2 10.8 Methods for Testing Mechanisms 10.8.1 Initial Studies 10.8.2 Catalysis, Inhibition 10.8.3 Isolation, Detection, or Trapping of Intermediates 10.8.4 Isotopic Labels 10.8.5 Regiochemistry, Stereochemistry, and Chirality 10.8.6 Kinetics 10.8.7 Solvent Polarity Effects 10.8.8 Substituent Effects 10.8.9 Primary Deuterium Isotope Effects 10.8.10 Barrier Data 10.9 Lessons from Biochemical Mechanisms 10.10 Summary 11. Cross-checks and Decision Boundaries 11.1 Cross-Checks are Critical to a Reasonable Hypothesis 11.2 Fundamentals Cross-Checks 11.3 Proton Transfer Keq Cross-Check 11.4 ΔpKa Rule Cross-Check 11.5 Leaving Group Cross-Check 11.6 Media pH Span Cross-Check 11.7 Stability of Intermediates Cross-Check 11.8 Electron Flow Pathway and Completeness Cross-Checks 11.9 Cross-Checks for Specific Paths 11.10 Summary 12. One Electron Processes 12.1 Radical Structure and Stability 12.1.1 Radical Structure 12.1.2 Bond Dissociation Energies 12.1.3 Radical Stabilities 12.2 Radical Path Initiation 12.3 Major Paths for Radicals Reacting with Neutrals 12.3.1 Abstraction 12.4 Unimolecular Radical Paths 12.4.1 Elimination or Fragmentation 12.4.2 Decarboxylation 12.4.3 Decarbonylation 12.4.4 Rearrangement 12.5 Termination Radical Paths 12.5.1 Radical–Radical Coupling 12.5.2 Radical–Radical Disproportionation 12.6 Radical path Combinations 12.6.1 SH2, Substitution Chain (Substitution, Homolytic, Bimolecular) 12.7 Approaches To radical Mechanisms 12.7.1 Common Radical Mechanism Errors 12.7.2 Radical Mechanism Example 12.8 Single-Electron Transfer, S.E.T., and Charged Radicals 12.8.1 Organometallic Formation 12.8.2 A Molecular Orbital Explanation of Single-Electron Transfer 12.9 Dissolving Metal Reductions 12.10 Electron Transfer Initiated Processes 12.10.1 SRN1Process (Substitution, Radical–Nucleophile, Unimolecular) 12.10.2 Other Electron Transfer Initiated Processes 12.11 One-Electron Path Summary 12.11.1 Initiation Is Required 12.11.2 Radical Paths 12.11.3 Radical Termination Paths 12.11.4 Common Radical Chain Reactions 13. Qualitative Molecular Orbital Theory and Pericyclic Reactions 13.1 Review of Orbitals as Standing Waves 13.1.1 Electrons as Waves 13.1.2 Standing Waves in One and Two Dimensions 13.1.3 Standing Waves in Three Dimensions: Atomic Orbitals 13.1.4 Mixing Atomic Orbitals into Molecular Orbitals 13.2 Orbital Interaction Diagrams 13.2.1 Atomic Orbital Interaction Diagram for Two Atoms 13.2.2 Electronegativity Effects 13.2.3 Carbanion Stabilization from a HOMO–LUMO Perspective 13.2.4 Carbocation Stabilization from a HOMO–LUMO Perspective 13.2.5 Free Radical Stabilization from a HOMO–LUMO Perspective 13.2.6 Nucleophile–Electrophile Interactions 13.3 Molecular Orbital Theory for Linear pi Systems 13.3.1 Two p Orbitals, a Simple Pi Bond 13.3.2 Three p Orbitals, the Allyl Unit 13.3.3 Four p Orbitals, the 1,3-Diene Unit 13.3.4 The Progression of Energies and Orbitals for Linear-ConjugatedSystems 13.4 MO Theory for Cyclic-Conjugated pi Systems 13.5 Perturbation of the Homo and Lumo 13.6 Delocalization of Sigma Electrons (More Advanced) 13.7 Concerted Pericyclic Cycloaddition Reactions 13.7.1 Introduction to Pericyclic Reactions 13.7.2 Cycloaddition Reactions 13.8 Concerted Pericyclic Electrocyclic Reactions 13.8.1 Four-Electron (4n) Electrocyclic Reactions 13.9 Concerted Pericyclic Sigmatropic Rearrangements 13.9.1 Four-Electron (4n) Cyclic Rearrangements 13.9.2 Six-Electron (4n + 2) Cyclic Rearrangements 13.9.3 Sigmatropic Migration with Inversion 13.10 Pericyclic Reactions Summary 14. Organic Structure Elucidation Strategies 14.1 A General Approach to Structure Elucidation 14.2 Mass Spectral Analysis—MS 14.3 Elemental Analysis 14.4 Getting a Molecular Formula 14.5 Infrared Spectra—IR 14.6 Carbon NMR Spectra—13C NMR or C-NMR 14.7 Proton NMR Spectra—1H NMR or H-NMR 14.8 Piecing a Spectral Jigsaw all Together 14.9 Extra Help—A Taste of 2D NMR 14.9.1 H H Correlation Spectroscopy—COSY 14.9.2 C H Correlation Spectroscopy—HMQC or HSQC 14.10 Structure Elucidation Summary Appendix. (A Collection of Important Tools) Bibliography Abbreviations Used in this Text Functional Group Glossary Composite pKa Chart Bond Strength Table Generic Classification Guide Flowcharts For the Classification of Electron Sources and Sinks Pathway Summary and Cross-checks Trends Guide Major Routes Summary Major Decisions Guide Thermodynamics and Kinetics Generation of Alternate Paths, Reaction Cubes Notes on Nomenclature A Bridge to Transition Metal Organometallics Hints to Problems from Chapters 8, 9, 10, and 11 Solutions to Odd Numbered Problems Index Cover back Using A Mechanistic Approach, This Book Helps Students Develop A Good Intuition For Organic Chemistry And The Ability To Approach And Solve Complex Problems -- Methods Of Analysis That Are Valuable And Portable To Other Fields. Features New Chapters That Expand On Problem-solving Methods And An Addition To The Appendix That Will Aid Students Transitioning From The Electron-pushing Approach Of Organic Chemistry To The Different Approach Of Inorganic Chemistry Supplies Additional New Exercises For Students With Answers To Odd-numbered Problems Included Provides Online Material For Adopting Faculty: Answers To The Text's Even-numbered Problems And An Exam File