《有机化学》课程教学资源（参考书籍）Organic Chemistry I as a Second Language Translating the Basic Concepts 2nd 2008, DR. DAVID R. KLEIN Johns Hopkins University

As a Second Language Organic Chemistry I Translating the Basic Concepts 2nd Edition NEED HELP IN YOUR SECOND SEMESTER? Get KIn' David R.Klein

INTRODUCTION HOW TO USE THIS BOOK Is organic chemistry really as tough as everyone says it is?The answer is yes and no. Yes,because you will spend more time on organic chemistry than you would spend in a course on underwater basket weaving.And no,because those who say its so touh have studied inefficiently Ask around,and you will find that most students think of organic chemistry as a memorization game.This is not true!Former organic chemistry students perpetuate the false rumor that organic chemistry is the toughest class on campus,because it makes them feel better about the poor grades that they received. If it's not about memorizing.then what is it?To answer this questionlet's compare organic chemistry to a movie.Picture in your mind a movie where the plot changes every second.The"Usual Suspects"is an excellent example.If you're in a movie theatre watching a movie like that,you can't leave even for a second because you would miss something important to the plot.So you try your hardest to wait until the movie is over before going to the bathroom.Sound familiar? Organic chemistry is very much the me.It is one long story and the oacymakes sense if you pay attention.The plot constanty develop everything ties into the plot.If your attention wanders for too long.you could easily get lost. OK,so it's a long movie.But don't I need to memorize it?Of course,there are ome thing vou ned to mmorize You needtokow om mportant terminclogy and some that req re a bito emoriza amo nt of p memorization is not that large.If I were to give you a list of 100 numbers,and asked you to memorize them all for an exam,you would probably be very upset by this.But at the same time,you can probably tell me at least 10 telephone numbers off the top of your head.Each one of those has 10 digits (including the area codes). You neve sat down to memorize all 10 telephone numbers.Rather,over time you slowly be cam dialing tho mbers until the point that you knew them.Let's see how this works in our movie analogy. You probably know at least one person who has seen one movie more than five times and can quote every line by heart.How can this person do that?It's not be- the movie The first ime you watch a movie.you learn the plot.After the secc nd time ou under tand why individual scenes are ne essary to dev op the plot.After the I time.you understand why the dialogue wa necessary to develop each scene.After the fourth time,you are quoting many of the lines by heart.Never at any time did you make an effort to memorize the lines.You

HOW TO USE THIS BOOK Is organic chemistry really as tough as everyone says it is? The answer is yes and no. Yes, because you will spend more time on organic chemistry than you would spend in a course on underwater basket weaving. And no, because those who say its so tough have studied inefficiently. Ask around, and you will find that most students think of organic chemistry as a memorization game. This is not true! Former organic chemistry students perpetuate the false rumor that organic chemistry is the toughest class on campus, because it makes them feel better about the poor grades that they received. If it’s not about memorizing, then what is it? To answer this question, let’s compare organic chemistry to a movie. Picture in your mind a movie where the plot changes every second. The “Usual Suspects” is an excellent example. If you’re in a movie theatre watching a movie like that, you can’t leave even for a second because you would miss something important to the plot. So you try your hardest to wait until the movie is over before going to the bathroom. Sound familiar? Organic chemistry is very much the same. It is one long story, and the story actually makes sense if you pay attention. The plot constantly develops, and everything ties into the plot. If your attention wanders for too long, you could easily get lost. OK, so it’s a long movie. But don’t I need to memorize it? Of course, there are some things you need to memorize. You need to know some important terminology and some other concepts that require a bit of memorization, but the amount of pure memorization is not that large. If I were to give you a list of 100 numbers, and I asked you to memorize them all for an exam, you would probably be very upset by this. But at the same time, you can probably tell me at least 10 telephone numbers off the top of your head. Each one of those has 10 digits (including the area codes). You never sat down to memorize all 10 telephone numbers. Rather, over time you slowly became accustomed to dialing those numbers until the point that you knew them. Let’s see how this works in our movie analogy. You probably know at least one person who has seen one movie more than five times and can quote every line by heart. How can this person do that? It’s not be￾cause he or she tried to memorize the movie. The first time you watch a movie, you learn the plot. After the second time, you understand why individual scenes are nec￾essary to develop the plot. After the third time, you understand why the dialogue was necessary to develop each scene. After the fourth time, you are quoting many of the lines by heart. Never at any time did you make an effort to memorize the lines. You INTRODUCTION v 6753_Klein_00.qxd 5/1/07 5:02 PM Page v

vi INTRODUCTION know them because they make sense in the grand scheme of the plot.If I were to give you a screenplay for a movie and ask you to memorize as much as you can in 10 10hours and played the same movie overaain five times.you would knowmost of the movie by heart.without even trying.You would know everyone's names,the order of the scenes,much of the dialogue,and so on. Organic chemistry is exactly the same.It's not about memorization.It's all about making sense of the plot,the scenes,and the individual concepts that make up our story.Of course you will need to remember all of the terminology.but with enough practice,the terminology will become second nature to you.So here's a brief preview of the plot. THE PLOT The first half of our story builds up to reactions,and we learn about the character- istics of molecules that help us understand reactions.We begin by looking at atoms. the building blocks of molecules,and what happens when they combine to form bonds.We focus on special bonds between certain atoms.and we see how the na- ture of bonds can affect the shape and stability of molecules.At this point.we nee a vocabulary to start talking about molecules,so we learn how to draw and name molecules.We see how molecules move around in space,and we explore the rela- tionships between similar types of molecules.At this point,we know the important characteristics of molecules,and we are ready to use our knowledge to explore reactions Reactions take up the rest of the course,and they are typically broken dowr into chapters based on functional groups.Within each of these chapters.there is ac- tually a subplot that fits into the grand story. HOW TO USE THIS BOOK This book will help you study more efficiently so that you can avoid wasting count- less hours.It will point out the major scenes in the plot of organic chemistry.The book will review the critical principles and explain why they are relevant to the rest of the course. In each section .you will he gi iven the tools to better unde tand y textbook a 】1 ectures.In other words,you ill learn the language of organi istry.This book cannot replace your textbook,your lectures,or other forms of study ing.This book is not the Cliff Notes of Organic Chemistry.It focuses on the basic concepts that will empower you to do well if you go to lectures and study in addi- tion to using this book.To best use this book,you need to know how to study in this course

know them because they make sense in the grand scheme of the plot. If I were to give you a screenplay for a movie and ask you to memorize as much as you can in 10 hours, you would probably not get very far into it. If, instead, I put you in a room for 10 hours and played the same movie over again five times, you would know most of the movie by heart, without even trying. You would know everyone’s names, the order of the scenes, much of the dialogue, and so on. Organic chemistry is exactly the same. It’s not about memorization. It’s all about making sense of the plot, the scenes, and the individual concepts that make up our story. Of course you will need to remember all of the terminology, but with enough practice, the terminology will become second nature to you. So here’s a brief preview of the plot. THE PLOT The first half of our story builds up to reactions, and we learn about the character￾istics of molecules that help us understand reactions. We begin by looking at atoms, the building blocks of molecules, and what happens when they combine to form bonds. We focus on special bonds between certain atoms, and we see how the na￾ture of bonds can affect the shape and stability of molecules. At this point, we need a vocabulary to start talking about molecules, so we learn how to draw and name molecules. We see how molecules move around in space, and we explore the rela￾tionships between similar types of molecules. At this point, we know the important characteristics of molecules, and we are ready to use our knowledge to explore reactions. Reactions take up the rest of the course, and they are typically broken down into chapters based on functional groups. Within each of these chapters, there is ac￾tually a subplot that fits into the grand story. HOW TO USE THIS BOOK This book will help you study more efficiently so that you can avoid wasting count￾less hours. It will point out the major scenes in the plot of organic chemistry. The book will review the critical principles and explain why they are relevant to the rest of the course. In each section, you will be given the tools to better understand your textbook and lectures. In other words, you will learn the language of organic chem￾istry. This book cannot replace your textbook, your lectures, or other forms of study￾ing. This book is not the Cliff Notes of Organic Chemistry. It focuses on the basic concepts that will empower you to do well if you go to lectures and study in addi￾tion to using this book. To best use this book, you need to know how to study in this course. vi INTRODUCTION 6753_Klein_00.qxd 5/1/07 5:02 PM Page vi

INTRODUCTION vii HOW TO STUDY There are two separate aspects to this course: 1.Understanding principles 2.Solving problems Although these two aspects are completely different,instructors will typically gauge your understanding of the principles by testing your ability to solve prob ems.So you must master both aspects of the course.The principles are in your textbook and in your lecture notes,but you must discover how to solve problems.Most students have a difficult time with this task.In this book,we explore some step-by-step processes for analyzing problems.There is a very simple habit that you must form If you go to a doctor with a pain in your stomach,you will get a series of ques tions:How long have you had the pain?Where is the pain?Does it come and go,or is it constant?What was the last thing you ate?and so on.The doctor is doing two very important and very different things.First,he has learned the right questions to ask.Next,he applies the knowledge he has together with the information he has gleaned to arrive at the proper diagnosis.Notice that the first step is asking the right questions Let's imagine that you want to sue MeDonald's because you spilled hot coffee in your lap.You go to an attorney and she asks you a series of questions that enable her to apply her knowledge to your case.Once again,the first step is asking questions. In fact,in any profession or trade,the first step of diagnosing a problem is al- ways to ask questions. Let's say you are trying to decide if your vant to be a doctor.There are some tough,penetrating questions that you should be asking your self.It all boils down to learning how to ask the right questions. The same is true with solving problems in this course.Unfortunately,you are expected to leamn how to do this on your own.In this book,we will look at some pes of problems and we wil se what auesion you should be asking ances.More importantly,we will als o be deve oping skills that will allow you to figure out what questions you should be asking for a problem that you have never seen before. Many students freak out on exams when they see a problem that they can't do If you could hear what was going on in their minds,it would sound something like this"I can't do itI'm gonna flunk."These thoughts are counterproductive and a waste of precious t e.Reme r that when all lse fails,the s al that you can ask yourself:"What questions should I be asking The only way to truly master problem-solving is to practice problems every day,consistently.You will never learn how to solve problems by just reading a book. You must try,and fail,and try again.You must learn from your mistakes.You must get frustrated when you can't so ove aproblem.That's the ng proc The worst t ing you can do is to read through the solu tons ma ual and think that you now know how to solve problems.It doesn't work that way.If you want an

HOW TO STUDY There are two separate aspects to this course: 1. Understanding principles 2. Solving problems Although these two aspects are completely different, instructors will typically gauge your understanding of the principles by testing your ability to solve problems. So you must master both aspects of the course. The principles are in your textbook and in your lecture notes, but you must discover how to solve problems. Most students have a difficult time with this task. In this book, we explore some step-by-step processes for analyzing problems. There is a very simple habit that you must form immediately: learn to ask the right questions. If you go to a doctor with a pain in your stomach, you will get a series of ques￾tions: How long have you had the pain? Where is the pain? Does it come and go, or is it constant? What was the last thing you ate? and so on. The doctor is doing two very important and very different things. First, he has learned the right questions to ask. Next, he applies the knowledge he has together with the information he has gleaned to arrive at the proper diagnosis. Notice that the first step is asking the right questions. Let’s imagine that you want to sue McDonald’s because you spilled hot coffee in your lap. You go to an attorney and she asks you a series of questions that enable her to apply her knowledge to your case. Once again, the first step is asking questions. In fact, in any profession or trade, the first step of diagnosing a problem is al￾ways to ask questions. Let’s say you are trying to decide if you really want to be a doctor. There are some tough, penetrating questions that you should be asking your￾self. It all boils down to learning how to ask the right questions. The same is true with solving problems in this course. Unfortunately, you are expected to learn how to do this on your own. In this book, we will look at some common types of problems and we will see what questions you should be asking in those circumstances. More importantly, we will also be developing skills that will allow you to figure out what questions you should be asking for a problem that you have never seen before. Many students freak out on exams when they see a problem that they can’t do. If you could hear what was going on in their minds, it would sound something like this: “I can’t do it . . . I’m gonna flunk.” These thoughts are counterproductive and a waste of precious time. Remember that when all else fails, there is always one ques￾tion that you can ask yourself: “What questions should I be asking right now?” The only way to truly master problem-solving is to practice problems every day, consistently. You will never learn how to solve problems by just reading a book. You must try, and fail, and try again. You must learn from your mistakes. You must get frustrated when you can’t solve a problem. That’s the learning process. The worst thing you can do is to read through the solutions manual and think that you now know how to solve problems. It doesn’t work that way. If you want an INTRODUCTION vii 6753_Klein_00.qxd 5/1/07 5:02 PM Page vii

viii INTRODUCTION A.you will need to sweat a little (no pain,no gain).And that doesn't mean that you should spend day and night memorizing.Students who focus on memorizing will ex- perience the pain,but few of them will get an A. The simple formula:Review the principles until you understand how each of them fits into the plot;then focus all of your remaining time on solving problems. Don't worry.The course is not that bad if you approach it with the right attitude.This book will act as a road map for your studying efforts

A, you will need to sweat a little (no pain, no gain). And that doesn’t mean that you should spend day and night memorizing. Students who focus on memorizing will ex￾perience the pain, but few of them will get an A. The simple formula: Review the principles until you understand how each of them fits into the plot; then focus all of your remaining time on solving problems. Don’t worry. The course is not that bad if you approach it with the right attitude. This book will act as a road map for your studying efforts. viii INTRODUCTION 6753_Klein_00.qxd 5/1/07 5:02 PM Page viii

CONTENTS Introduction iii CHAPTER 1 BOND-LINE DRAWINGS 1 1.1 How to Read Bond-Line Drawings 1 1.2 How to Draw Bond-Line Drawings 1.3 Mistakes to Avoid7 1.4 More Exercises 8 1.5 Identifying Formal Charges 10 1.6 Finding Lone Pairs That Are Not Drawn 14 CHAPTER 2 RESONANCE 20 2.1 What Is Resonance?20 2.4 Drawing Good Arrows 27 2.5 Formal Charges in Resonance Structures 29 2.6 Drawing Resonance Structures-Step by Step 33 2.7 Drawing Resonance Structures-By Recognizing Patterns 38 one Pair Next to a Pi Bond 38 A Lone Pair Next to a Positive Charge 41 A Pi Bond Next to a Positive Charge 43 A Pi Bond Between Two Atoms,Where One of Those Atoms Is Electronegative (N.O.etc.)44 Pi Bonds Go ng All the Way Around a Ring 45 2.8 Ass essing the Relative Importance of Resonance Structures 47 CHAPTER 3 ACID-BASE REACTIONS 53 3.1 Factor 1-What Atom Is the Charge on?54 3.2 Factor 2 -Resonance 57 3.3 Factor 3-Induction 62 34 Factor 4-Orbitals 66 3.5 Ranking the Four Factors 67 3.6 Quan easureme avalues)71 3.7 Predicting the Postion of Equilibrium7 3.8 Showing a Mechanism 73

Introduction iii CHAPTER 1 BOND-LINE DRAWINGS 1 1.1 How to Read Bond-Line Drawings 1 1.2How to Draw Bond-Line Drawings 5 1.3 Mistakes to Avoid 7 1.4 More Exercises 8 1.5 Identifying Formal Charges 10 1.6 Finding Lone Pairs That Are Not Drawn 14 CHAPTER 2 RESONANCE 20 2.1 What Is Resonance? 20 2.2 Curved Arrows: The Tools for Drawing Resonance Structures 21 2.3 The Two Commandments 24 2.4 Drawing Good Arrows 27 2.5 Formal Charges in Resonance Structures 29 2.6 Drawing Resonance Structures—Step by Step 33 2.7 Drawing Resonance Structures—By Recognizing Patterns 38 A Lone Pair Next to a Pi Bond 38 A Lone Pair Next to a Positive Charge 41 A Pi Bond Next to a Positive Charge 43 A Pi Bond Between Two Atoms, Where One of Those Atoms Is Electronegative (N, O, etc.) 44 Pi Bonds Going All the Way Around a Ring 45 2.8 Assessing the Relative Importance of Resonance Structures 47 CHAPTER 3 ACID–BASE REACTIONS 53 3.1 Factor 1—What Atom Is the Charge on? 54 3.2Factor 2—Resonance 57 3.3 Factor 3—Induction 62 3.4 Factor 4—Orbitals 66 3.5 Ranking the Four Factors 67 3.6 Quantitative Measurement (pKa values) 71 3.7 Predicting the Position of Equilibrium 71 3.8 Showing a Mechanism 73 ix CONTENTS 6753_Klein_00.qxd 5/1/07 5:02 PM Page ix

X CONTENTS CHAPTER 4 GEOMETRY 76 4.1 Orbitals and Hybridization States 76 4.2 Geometry 80 CHAPTER 5 NOMENCLATURE 84 5.1 Functional Group 85 5.2 Unsaturation 5.3 Naming the Parent Chain 89 5.4 Naming Substituents 91 5.5 Stereoisomerism 95 5.7 Comn 103 5.8 Going from a Name to a Structure 104 CHAPTER 6 CONFORMATIONS 106 6.1 How to Draw a Newman Projection 107 6.2 Ranking the Stability of Newman Projections 111 6.3 Drawing Chair Conformations 115 6.4 Placing Groups on the Chair 118 6.5 Ring Flipping 123 6.6 Com 129 133 CHAPTER 7 CONFIGURATIONS 134 7.1 Locating Stereocenters 135 7.2 Determining the Configuration of a Stereocenter 138 7.3 Nomenclature 146 7.4 Drawing Enantiomers 151 75 Diastereomers 156 7.6 Meso Co unds 157 7.8 Optical Activity 165 CHAPTER 8 MECHANISMS 167 8.1 Curved Arrows 168 8.2 Arrow Pushing 173 8.3 Drawing Intermediates 175 8.4 Nucleophiles and Electrophiles 178 8.5 Bases Versus Nucleophiles 179 8.6 The Regiochemistry Is Contained Within the Mechanism 182

CHAPTER 4 GEOMETRY 76 4.1 Orbitals and Hybridization States 76 4.2Geometry 80 CHAPTER 5 NOMENCLATURE 84 5.1 Functional Group 85 5.2Unsaturation 87 5.3 Naming the Parent Chain 89 5.4 Naming Substituents 91 5.5 Stereoisomerism 95 5.6 Numbering 98 5.7 Common Names 103 5.8 Going from a Name to a Structure 104 CHAPTER 6 CONFORMATIONS 106 6.1 How to Draw a Newman Projection 107 6.2Ranking the Stability of Newman Projections 111 6.3 Drawing Chair Conformations 115 6.4 Placing Groups on the Chair 118 6.5 Ring Flipping 123 6.6 Comparing the Stability of Chairs 129 6.7 Don’t Be Confused by the Nomenclature 133 CHAPTER 7 CONFIGURATIONS 134 7.1 Locating Stereocenters 135 7.2Determining the Configuration of a Stereocenter 138 7.3 Nomenclature 146 7.4 Drawing Enantiomers 151 7.5 Diastereomers 156 7.6 Meso Compounds 157 7.7 Drawing Fischer Projections 160 7.8 Optical Activity 165 CHAPTER 8 MECHANISMS 167 8.1 Curved Arrows 168 8.2Arrow Pushing 173 8.3 Drawing Intermediates 175 8.4 Nucleophiles and Electrophiles 178 8.5 Bases Versus Nucleophiles 179 8.6 The Regiochemistry Is Contained Within the Mechanism 182 x CONTENTS 6753_Klein_00.qxd 5/1/07 5:02 PM Page x

CONTENTS xi 8.7 The Stereochemistry Is Contained Within the Mechanism 185 8.8 A List of Mechanisms 190 CHAPTER 9 SUBSTITUTION REACTIONS 211 9.1 The Mechanisms 211 9.2 Factor 1-The Electrophile(Substrate)214 9.3 Factor 2-The Nucleophile 217 9.4 Factor 3-The Leaving Group 220 9.5 Factor 4The Solvent 223 9.6 Using All Four Factors 22 9.7 Substitution Reactions Teach Us Some Important Lessons 227 CHAPTER 10 ELIMINATION REACTIONS 229 10.1 Mechanisms(El and E2)230 10.2 Factor 1-The Substrate 231 103 Factor 2-The Base 232 10.4 Factor3-The Leaving Group 35 10.5 Factor4Solvent Effects 36 10.6 Using All of the Factors 236 10.7 Elimination Reactions-Regiochemistry and Stereochemistry 238 CHAPTER 11 ADDITION REACTIONS 242 11.1 Terminology Describing Regiochemistry 242 y Describing Stereochemistry 11.3 Adding H and H 11.4 Adding H and X,Markovnikov 256 11.5 Adding H and Br,Anti-Markovnikov 263 11.6 Adding H and OH,Markovnikov 268 11.7 Adding H and OH,Anti-Markovnikov 272 11.8 Synthesis Techn ques 277 11Adding Br and Br Adding Br and OH 11.10 Adding OH and OH,Anti 290 11.11 Adding OH and OH,Syn 293 11.12 Oxidative Cleavage of an Alkene 296 CHAPTER 12 PREDICTING PRODUCTS 299 12.1 General Tips for Predicting Products 299 12.2G tting Prac 1ce30 12.3 Substitution Versus Elimination Reactions 311 12.4 Looking Forward 315

8.7 The Stereochemistry Is Contained Within the Mechanism 185 8.8 A List of Mechanisms 190 CHAPTER 9 SUBSTITUTION REACTIONS 211 9.1 The Mechanisms 211 9.2Factor 1—The Electrophile (Substrate) 214 9.3 Factor 2—The Nucleophile 217 9.4 Factor 3—The Leaving Group 220 9.5 Factor 4—The Solvent 223 9.6 Using All Four Factors 226 9.7 Substitution Reactions Teach Us Some Important Lessons 227 CHAPTER 10 ELIMINATION REACTIONS 229 10.1 Mechanisms (E1 and E2) 230 10.2Factor 1—The Substrate 231 10.3 Factor 2—The Base 232 10.4 Factor 3—The Leaving Group 235 10.5 Factor 4—Solvent Effects 236 10.6 Using All of the Factors 236 10.7 Elimination Reactions—Regiochemistry and Stereochemistry 238 CHAPTER 11 ADDITION REACTIONS 242 11.1 Terminology Describing Regiochemistry 242 11.2Terminology Describing Stereochemistry 244 11.3 Adding H and H 253 11.4 Adding H and X, Markovnikov 256 11.5 Adding H and Br, Anti-Markovnikov 263 11.6 Adding H and OH, Markovnikov 268 11.7 Adding H and OH, Anti-Markovnikov 272 11.8 Synthesis Techniques 277 11.9 Adding Br and Br; Adding Br and OH 285 11.10 Adding OH and OH, Anti 290 11.11 Adding OH and OH, Syn 293 11.12Oxidative Cleavage of an Alkene 296 CHAPTER 12 PREDICTING PRODUCTS 299 12.1 General Tips for Predicting Products 299 12.2 Getting Practice 300 12.3 Substitution Versus Elimination Reactions 311 12.4 Looking Forward 315 CONTENTS xi 6753_Klein_00.qxd 5/1/07 5:02 PM Page xi

xii CONTENTS CHAPTER 13 SYNTHESIS 316 13.1 One-step Syntheses 318 13.2 Multistep Syntheses 13.3 Retrosynthetic Analysis 330 13.4 Creating Your Own Problems 331 Answer Key 333 Index 354

CHAPTER 13 SYNTHESIS 316 13.1 One-step Syntheses 318 13.2Multistep Syntheses 329 13.3 Retrosynthetic Analysis 330 13.4 Creating Your Own Problems 331 Answer Key 333 Index 354 xii CONTENTS 6753_Klein_00.qxd 5/1/07 5:02 PM Page xii

CHAPTER BOND-LINE DRAWINGS To do well in organic chemistry.you must first learn to interpret the drawings that you see a drawing of a molecule it is absolutely riti cal that you can read all of the information contained in that drawing.Without this skill,it will be impossible to master even the most basic reactions and concepts. Molecules can be drawn in many ways: HHHH H-CC=C (CH3)2CHCH=CHCOCH3 √0 Without a doubt,the last structure (bond-line drawing)is the quickest to draw.the quickest to read.and the best way to communicate.Open your textbook ond half and ou will find that every e is plastered with neMot studentswl ain a faiiarity w ese drawings over time,not realizing how absolutely critical it is to be able to read these drawings flu- ently.This chapter will help you develop your skills in reading these drawings quickly and fluently. 1.1 HOW TO READ BOND-LINE DRAWINGS Bond-line drawings show the carbon skeleton(the connections of all the carbor atoms that build up the backbone of the molecule) with ny functiona groups that are atta hed.,such asOH orBr Lines are drawn nformar so that the end of every line represents a carbon atom.For example,the following compound has 6 carbon atoms: It is a common mistake to forget that the ends of lines represent carbon atoms as well.For example,the following molecule has six carbon atoms(make sure you can count them):

To do well in organic chemistry, you must first learn to interpret the drawings that organic chemists use. When you see a drawing of a molecule, it is absolutely criti￾cal that you can read all of the information contained in that drawing. Without this skill, it will be impossible to master even the most basic reactions and concepts. Molecules can be drawn in many ways: Without a doubt, the last structure (bond-line drawing) is the quickest to draw, the quickest to read, and the best way to communicate. Open your textbook to any page in the second half and you will find that every page is plastered with bond-line drawings. Most students will gain a familiarity with these drawings over time, not realizing how absolutely critical it is to be able to read these drawings flu￾ently. This chapter will help you develop your skills in reading these drawings quickly and fluently. 1.1 HOW TO READ BOND-LINE DRAWINGS Bond-line drawings show the carbon skeleton (the connections of all the carbon atoms that build up the backbone, or skeleton, of the molecule) with any functional groups that are attached, such as – OH or – Br. Lines are drawn in a zigzag format, so that the end of every line represents a carbon atom. For example, the following compound has 6 carbon atoms: It is a common mistake to forget that the ends of lines represent carbon atoms as well. For example, the following molecule has six carbon atoms (make sure you can count them): C C (CH3)2CHCH=CHCOCH3 O H H C C H C HH H H H H C O C H H H 1 CHAPTER1 BOND-LINE DRAWINGS 6753_Klein_01.qxd 5/1/07 5:03 PM Page 1