JosephC.Sloop,author

Structure

Function

Mechanism

About the Author

Dr. Joseph C. Sloop, Associate Professor, Georgia Gwinnett College

Dr. Sloop, a North Carolina native, completed requirements for his B. S. degree with Special Attainments in Chemistry from Davidson College under the direction of Dr. Felix Carroll in organic photochemistry in 1983. He was commissioned into the U. S. Army Chemical Corps upon graduation. He then attended North Carolina State University (NCSU), completing work toward a Masters degree in Chemistry in fluorinated heterocycle synthesis under the direction of Dr. Carl Bumgardner. He joined the faculty of the United States Military Academy (USMA) at West Point in 1990, where he taught general and organic chemistry. From 1994 -1996, he taught organic chemistry and environmental toxicology at Drury College, Fort Leonard Wood campus. In 2000, he was selected by the U. S. Army for doctoral training and returned to NCSU where he completed requirements for a Ph.D. under the direction of Dr. David Shultz in organic magnetochemistry. Upon graduation, Dr. Sloop rejoined the USMA faculty at West Point in 2003, teaching organic chemistry and directing the undergraduate research program for the Department of Chemistry and Life Science until 2009. Upon his retirement from military service, Dr. Sloop accepted a position as Associate Professor in the School of Science and Technology at Georgia Gwinnett College, where he currently teaches a variety of chemistry courses. He is the recipient of several teaching and research awards with many scientific and science education papers to his credit as well as contributing author to the 2007 text entitled Fluorine Chemistry Research Advances.

About the Book

This text is specifically designed to help introductory Organic Chemistry students understand the fundamental concepts covered in undergraduate organic chemistry. The purpose of this book is three-fold: to explode the misconceptions and misgivings that are prevalent regarding this vast subject, provide additional insight for students on a number of concepts essential to mastery of organic chemistry, and explore alternative learning strategies to assist the beginning organic chemistry student in applying a specialized problem solving technique which centers on structure, function and a mechanistic approach. Examples of key chemical transformations are dissected and analyzed to assist students in improving their problem-solving skills. Each chapter contains a number of additional problems and the solutions to those problems are provided at the end of each chapter.

Preface

What is it about organic chemistry that strikes such fear into the hearts of budding

scientists, doctors and chemists? Why do students approach this subject with trepidation?

Although these questions are not easily answered, over the years of teaching

organic chemistry we have learned how students think about organic chemistry. The

purpose of this book is three-fold: to explode the misconceptions and misgivings that are

prevalent regarding this vast subject, provide additional insight for students on a number

of concepts essential to mastery of organic chemistry, and explore alternative learning

strategies to assist the beginning organic chemistry student in applying a specialized

problem solving technique which centers on structure, function and a mechanistic

approach. The goal for the audience is to, given the appropriate tools, arrive at the

realization that introductory organic chemistry may not only be mastered, but may be

enjoyed as well.

Table of Contents

_____ Chapter Topic__________________________________________________ Page___ Chapter 1 Studying for Success 1 1.1 Exploding the Myth 1 1.2 Being a Student of the Subject 1 1.3 Studying Organic Chemistry: What You must Know 2 1.4 Optimizing Your Lecture Experience 4 1.5 Working Additional Problems 5 1.6 Seeking Additional Help 5 1.7 Test Taking 5 Chapter 2 Fundamentals 6 2.1 Introduction 6 2.2. Atomic Properties 6

2.2.a. Atoms and the Periodic Table 2.2.b. The Pauli Exclusion Principle and Hunds Rule Attraction Between Electrons 2.2.c. Lewis Symbols Depiction of Valence Electrons 2.2.d. Electronegativity Attraction Between Atoms and Electrons

2.3 Bonding Theories 9 2.3.a. VSEPR 2.3.b. Valence Bond Theory 2.3.c. Hybridization 2.3.d. MO Theory

2.4 Types of Bonds and Compounds 16 2.4.a. Ionic Bonds 2.4.b. Polar Covalent Bonds 2.4.c. Covalent Bonds

2.5 Summary 19 Solved Problems 19 Chapter 3 Drawing Chemical Structures 23 3.1 Formal Charges and Electron Dot Structures A Form of Electronic Bookkeeping 23 3.2 Kekul (Line-Bond) and Skeletal Structures of sp3 Hybridized Molecules 23 3.3 Newman Projections 26 3.4 Skeletal Structures of Cyclohexanes 27 3.5 Summary 29 Solved Problems 30 Chapter 4 Stability of Carbon Compounds and Reactive Intermediates 31 4.1 Alkane Stability 31

4.1.a. Acyclic (non-cyclic) Alkanes 4.1.b. Cyclic Alkanes 4.1.c. Conformational Analysis of Substituted Cyclohexanes

4.2 Alkene Stability 39 4.2.a. Rigidity of the Double Bond 4.2.b. Steric Consequences 4.2.c. Hybridization Consequences 4.2.d. Hyperconjugation Consequences 4.3 Stability of Aromatic Compounds 41 4.3.a. The Uniqueness of Benzene

4.3.b. The Resonance Energy of Benzene

Table of Contents

_____ Chapter Topic__________________________________________________ Page___ 4.4 Carbocation Stability 43

4.4.a. Simple Carbocations 4.4.b. Resonance Stabilized Carbocations

4.5 Stability of Carbon Radicals 45 4.6 Stability of Carbanions 47 4.7 Summary 48 Solved Problems 49 Chapter 5 Isomerism and Stereochemistry 52 5.1 Types of Isomerism 52 5.1.a. Constitutional Isomerism 5.1.b. Stereoisomerism 5.2 Handedness and Chiral Molecules 53 5.3 Optical Activity 54 5.4 The Cahn-Ingold-Prelog (C-I-P) System: Establishing Priorities 55 5.5 Configuration of Alkenes: cis/trans or E/Z 56 5.6 Absolute Configuration of Stereoisomers Other Than Alkenes: the R/S Convention 57 5.7 Fischer Projections 58 5.8 Meso Compounds 60 5.9 Haworth Projections 60 Solved Problems 61 Chapter 6 - Function of Reagents in Organic Chemistry 64 6.1 Acids and Electrophiles 64 6.2 Bases and Nucleophiles 65 6.3 Summary 66 Solved Problems 66 Chapter 7 Step-by-Step: How Reactions Occur 68 7.1 Acid-Base Reactions/Proton Transfers 68 7.2 Alkene Additions 70 7.3 Nucleophilic Substitutions: SN2 and SN1 Reactions 73 7.3.a. The Bimolecular SN2 Process 7.3.b. The Unimolecular SN1 Process 7.4 Eliminations: E2 and E1 Reactions 78 7.4.a. The Bimolecular E2 Process 7.4.b. The Unimolecular E1 Process 7.5 Competition Between Nucleophilic Substitutions and Eliminations 83 7.6 Electrophilic Aromatic Substitution 85 7.6.a. Bromination of Benzene 7.6.b. Nitration of Benzene 7.6.c. Friedel-Krafts Alkylation of Benzene 7.6.d. Directing Ability of Substituents on the Benzene Ring 7.6.e. Competition Between Directing Groups: Preparation of Trisubstituted Aromatic Molecules 7.7 Nucleophilic Addition to Carbonyls and Nucleophilic Acyl Substitutions 93 7.7.a. Reactivity of Carbonyl Species Towards Nucleophilic Attack 7.7.b. Nucleophilic Addition to Carbonyls and Nucleophilic Acyl Substitution 7.7.c. Reduction of Esters: A Double-Barrel Reaction: Nucleophilic Acyl

Substitution and Nucleophilic Addition to a Carbonyl 7.7.d. Carbonyl Analogs

Table of Contents

_____ Chapter Topic__________________________________________________ Page___ 7.8 Carbonyl Nucleophiles: - Substitution Reactions 102 7.8.a. Halogenation 7.8.b. Alkylation 7.8.c. Carbonyl Condensations 7.9 The Stork Reaction: Enamine Addition to ,-Unsaturated Carbonyls 106 7.10 Oxidation of Alcohols with Cr[VI] Reagents 107 7.11 Summary 110 Solved Problems 110 Appendix A - Reducing Agents 125 Appendix B - Oxidizing Agents 128 Index of Key Terms 132 Index of Chemical Species 134