From the Inside Flap
To the Student
As you begin your study of organic chemistry, yon might feel overwhelmed by the number of compounds, names, reactions, and mechanisms that confront you. You may even wonder whether you can learn all this material in a single year. The most important function of a textbook is to organize the material to show that most of organic chemistry consists of a few basic principles and many extensions and applications of these principles. Relatively little memorization is required if you grasp the major concepts and develop flexibility in applying those concepts. Frankly, I have a poor memory, and I hate memorizing lists of information. I don't remember the specifics of most of the reactions and mechanisms in this book, but I can work them out by remembering a few basic principles, like "alcohol dehydrations usually go by E1 mechanisms:"
Still, you'll have to learn some facts and fundamental principles to serve as the working "vocabulary" of each chapter. As a student, I learned this the hard way when I made a D on my second organic chemistry exam. I thought organic would be like general chemistry, where I could memorize a couple of equations and fake my way through the exams. For example, in the ideal gas chapter, I would memorize pv = nrT, and I was good to go. When I tried the same approach in organic, I got a D. We learn by making mistakes, and I learned a lot in organic chemistry.
In writing this book, I've tried to point out a small number of important facts and principles that should be learned to prepare for solving problems. For example, of the hundreds of reaction mechanisms shown in this book, about 20 are the fundamental mechanistic steps that combine into the longer, more complicated mechanisms. I've highlighted these fundamental mechanisms in Key Mechanism boxes to alert you to their importance. Spectroscopy is another area where a student might feel pressured to memorize hundreds of facts, such as NMR chemical shifts and infrared vibration frequencies. I couldn't do that, so I've always gotten by with knowing about a dozen NMR chemical shifts and about a dozen IR vibration frequencies, and knowing how they are affected by other influences. I've listed those important infrared frequencies in Table 12-2 and the important NMR chemical shifts in Table I 3-3.
Don't try to memorize your way through this course. It doesn't work; you have to know what's going on so you can apply the material. Also, don't think (like I did) that you can get by without memorizing anything. Read the chapter, listen carefully to the lectures, and work the problems. The problems will tell you whether or not you know the material. If you can do the problems, you should do well on the exams. If you can't do the problems, you probably won't be able to do the exams, either. If you keep having to look up something to do the problems, that item is a good one to learn.
Here are some hints I give my students at the beginning of the course:
- Read the material in the book before the lecture (expect 13-15 pages per lecture). Knowing what to expect and what is in the book, you can take fewer notes and spend more time listening and understanding the lecture.
- After the lecture, review you notes and the book, and do the in-chapter problems. Also, read the material for the next lecture.
- If you are confused about something, visit your instructor during office hours immediately, before you fall behind. Bring your attempted solutions to problems with you to show your instructor where you are having trouble.
- To study for the exam, begin by reviewing each chapter and your notes, then concentrate on the end-of-chapter problems. Also use old exams for practice, if available.
Remember the two "golden rules" of organic chemistry.
- DON'T GET BEHIND! The course moves too fast, and it's hard to catch up.
- WORK LOTS OF PROBLEMS. Everyone needs the practice, and problems show where you need more work.
Several kinds of study aids are provided to emphasize and review the most important points.
Summary Tables. Whenever a large amount of material lends itself to a concise summary, a summary table is provided to compare and contrast this material. For example, the following summary table compares the factors affecting SN1 and SN2 reactions:
Reaction Summaries. At the conclusion of each section on syntheses or reactions of a functional group ("Reactions of Alkenes," for example), a summary table is provided for efficient review. Each summary, highlighted by a blue background, includes cross-references to reactions that are discussed elsewhere.
Mechanism Boxes. In this edition, I've added anew design element to help you fin(( the important mechanisms easily when you review a chapter. These mechanism boxes (about 100 total) have large blue headings that make them easy to see as you thump through the chapter. Please let me know if you think of ways they might be made more helpful. In choosing which mechanisms to put in boxes, I've tried to include most of the standard mechanisms that most students can work through and understand after they've finished studying the chapter.
The most important of these mechanisms (about 20) are in Key Mechanism boxes. These are the fundamental mechanistic principles that make organic chemistry (and biochemistry) work. They are the pieces that compose most of the other, longer mechanisms given in the book. Thirty years from now, even if you don't remember anything else from your organic chemistry course, I hope you will still understand these fundamental ways that compounds react.
Problems. The in-chapter problems appear right after the relevant sections of the text. These problems provide immediate review and reinforcement of the material as you learn it, helping to make sure you understand each section well enough before moving on to the next. Later, end-of-chapter problems promote additional review and practice. Your instructor may choose to assign specific problems that reflect the emphasis of the lectures. Problems with red stars (*) are more difficult problems that require extra thought and perhaps some extension of the material presented in the chapter.
Solved Problems where appropriate, solved problems (highlighted by a beige background) are provided to show how you might approach a particular type of problem and what kind of answer is expected. For example, a solved problem might work through a mechanism to show how it is broken down into individual steps and how red curved arrows show movement of electrons.
Solved problems are often followed by another problem to give students an immediate opportunity to practice the principles covered in the solved problems.
Glossaries. Each chapter ends with a glossary that defines and explains technical terms introduced in that chapter. New terms defined in the glossary are printed in boldface the first time they appear in the chapter. Don't think of the glossaries as simply dictionaries for looking up words. The Index works better for that. The real purpose of the glossaries is as study aids for reviewing the material. Read through them after you read each chapter, and they will help to jog your memory as you go over the definitions and make sure you understand and can use all the new terms.
Chapter 8 Glossary
addition. A reaction involving an increase in the number of groups attached to the alkene and a decrease in the number of elements of unsaturation. (p. 314)
anti addition: An addition in which two groups add to opposite faces of the double bond (as in addition of Br2). (p. 326)
electrophilic addition: An addition in which the electrophile bonds to one of the double-bonded carbons first, followed by the nucleophile. (p. 315)
syn addition: An addition in which two groups add to the same face of the double bond (as in osmium tetroxide hydroxylation). (p. 326)
addition polymer (chain-growth polymer). A polymer that results from rapid addition of one molecule at a time to a growing polymer chain, usually with a reactive intermediate (canon, radical, or anion) at the growing end of the chain. (p. 352)
alkoxymercuration. The addition of mercuric acetate to an alkene in an alcohol solution, forming an alkoxymercurial intermediate. Demercuration gives an ether. (p. 326)
Problem-Solving Strategies. The problem-solving strategies (highlighted by a green background) suggest methods for approaching complicated problems, such as those that require proposing mechanisms and developing multi-step syntheses. Students often have trouble seeing how to approach problem solving, and these strategies are meant to help you break problems down into simpler pieces. Although organic chemistry cannot be reduced to a rote process that guarantees an answer, experienced chemists instinctively approach problems in ways that are more likely to lead to solutions. The suggestions in the problem-solving discussions approximate what an experienced chemist is likely to do in approaching these problems. They serve as a starting point, not a guaranteed route to the answers.
Problem-Solving Hints. These suggestions (green headings in the marginal column at the side of the page) are provided to remind you of facts or principles that are likely to be useful for solving common types of problems. These are the tips I give my own students when I help them work problems and review for exams. These hints highlight material that is sometimes overlooked but plays an important role in solving problems.
Essential Problem-Solving Skills. This list is provided at the end of each chapter to remind you of the kinds of skills needed to solve typical problems associated with the material in that chapter. When you finish a chapter, this list can point out concepts you might need to review, or it might suggest types of problems and solutions you have not considered. Reviewing the problem-solving skills is often a good prelude to doing the end-of-chapter problems.
Use of Color to Help Organize Material. Color is used to highlight major features for easy location: the blue backgrounds of summary tables and beige backgrounds of solved problems shown above are examples.
- Problem-Solving features; background color of problem-solving strategies and skills, and headings for problem-solving hints, are shown in green.
- Key definitions and rules are in blue type.
- Curved red arrows are used throughout for "electron pushing," to show the flow of electrons through the course of a reaction.
- A blue pointing hand indicates the introduction of an important general type of reaction. In most cases, specific examples and variations of that type of reaction will follow the general reaction.
The variety of available colors makes it possible to highlight and distinguish key aspects of reactions, structures, and molecular drawings, and to distinguish atoms and bonds within molecules and transition states.
You will occasionally come across notes in the margins that highlight the many biological, medical, industrial, and societal uses of organic chemistry. These margin notes were added to provide a direct connection between organic chemistry concepts and real-life applications of those concepts.
I am always interested to hear from students using this book. If you have any suggestions about how the book might be made better, or if you've found an error, please let me know. (L. G. Wade, Whitman College, Walla Walla, WA, 99362: E-mail email@example.com). I take students' suggestions seriously, and hundreds of them now appear in this book. For example, Whitman student Brian Lian suggested Figure 21-9, and University of Minnesota student (and racing driver) Jim Coleman gave me the facts on methanol use at Indianapolis.
Good luck with your study of organic chemistry. I'm certain you will enjoy this course, especially if you let yourself relax and develop an interest in how organic compounds influence our lives. My goal in writing this book has been to make the process a little easier: to build the concepts logically on top of each other, so they flow naturally from one to the next. The hints and suggestions for problem-solving have helped my students in the past, and I hope some of them will help you to learn and use the material. Even if your memory is worse than mine (highly unlikely), you should be able to do well in organic chemistry. I hope this will be a good learning experience for all of us.
Solutions Manual (0-13-060028-8). Brief answers to many of the in-chapter problems are given at the back of this book. These answers are sufficient for a student on the right track, but they are of limited use to one who is having difficulty working the problems. The Solutions Manual, prepared by Jan W. Simek of California Polytechnic State University, contains complete solutions to all the problems. The Solutions Manual also gives helpful hints on how to approach each kind of problem. This supplement is a useful aid for any student, and it is particularly valuable for students who feel they understand the material but need more help with problem solving. Appendix 1 of the Solutions Manual summarizes the IUPAC system of nomenclature. Appendix 2 reviews and demonstrates how acidity varies with structure in organic molecules, and how one can predict the direction of an acid-base equilibrium.Students and instructors can use this student resource free of charge. Instructors can also use of the Syllabus Manager tool on the Companion Web site to create a syllabus, accessible anywhere and anytime by students, with assignments from on-line and print materials. Many of the resources on the Instructor Resource CD are also available to students and instructors on this Web site, as well as practice exercises and links to current readings and external Web sites.
The Companion Web site is a valuable self-study resource for students. Several sets of practice exercises in multiple-choice format test their knowledge of the chapter. Hints for each question are provided, and once students submit a quiz for grading, answer-specific feedback is immediately provided.
Several galleries feature interactive elements that help explain difficult concepts in the chapter: Student Tutorials show students how to think about certain crucial topics in organic chemistry; the Molecule Gallery features hundreds of 3D molecular models showing alternate representations; the Animation Gallery has over forty animations of key mechanisms.
--SCAN- To the Instructor
In writing the first edition of this text, my goal was to produce a modern, readable text that uses the most effective techniques of presentation and review. Subsequent editions extended and refined that goal, with substantial rewriting and reorganization and with the addition of several new features. This fifth edition incorporates even more refinements than the fourth, with revisions in the organization, writing, and graphics.
- Mechanism Boxes. About 100 of the most important mechanisms have been organized into mechanism boxes, with large blue headings for easy review. I've tried to choose most of the standard mechanisms that nearly everyone teaches; yet, in some cases, it seems that other mechanisms would be good candidates. If there are additional mechanisms that should be boxed, or some that should not be boxed, please let me know what you think.
In choosing the Key Mechanisms, I've used two major criteria. If the mechanism is one of the fundamental mechanisms that make up the longer, more complex mechanisms, then it must be a Key Mechanism. Examples are SN1, SN2, E1, E2, nucleophilic acyl substitution, electrophilic aromatic substitution, etc. The other criterion is more subjective. If the mechanism is one of the ones I routinely expect students to do on exams, then it is a Key Mechanism. Examples are formation of imines and acetals, aldol and Claisen condensations, etc. If you feel I have left one out or included one that should not be a Key Mechanism, please let me know.
- Updated Coverage. Several new sections have been included to cover new material or material of current interest.
Chapter 4: A new section on free-radical inhibitors has been added to show students how some of the common inhibitors break the free-radical chain reaction, and their importance in chemistry and biochemistry.
Chapter 5: Using the Mislow and Siegel definition (J. Am. Chem. Soc. 1984, 106, 3319), I have introduced the term stereocenter and explained the differences between this term and the IUPAC terms chirality center and asymmetric carbon atom (or chiral carbon atom). The term stereocenter is much broader than the more precise term asymmetric carbon atom, and it assumes that one already knows the stereochemical properties of the molecule (to know which bonds will give rise to stereoisomers upon their interchange). Therefore, I have continued to encourage students to identify the (immediately apparent) asymmetric carbon atoms to use as tools in examining a molecule to determine its stereochemistry.
Chapter 8: The Nobel prize-winning asymmetric reduction work by Noyori and Knowles is discussed, together with its implications for enantioselective drug synthesis.
Chapter 14: The Nobel prize-winning Sharpless asymmetric epoxidation is discussed, together with the factors that selectively enhance the formation of one enantiomer of the product.
Chapter 12: All the infrared spectra have been printed in a larger format, allowing the positions of absorptions to be determined more precisely.
Chapter 13: The NMR spectra have been converted to high-field (300 MHz) spectra from the excellent Aldrich collection.
Chapter 16: A section has been added discussing the aromaticity of Fullerenes and their relationship to other allotropes of carbon.
Chapter 24: I've added a new section to discuss prions: proteins which are thought to be infectious because of misfolding, resulting in clumping and formation of plaques.
- Electrostatic Potential Maps. I have introduced electrostatic potential maps in cases where they might help students to visualize the charge distribution of a species in a way that helps to explain the electrophilic or nucleophilic nature of a compound. In introducing EPMs, I've emphasized their qualitative nature without stressing their mathematical derivation. As a result, I've explained and used EPMs much like they are introduced in the general chemistry textbooks, and I've simply built on their use in general chemistry.
The entire book has been edited, with many extensive sections rewritten to enhance clarity. As in the first edition, each new topic is introduced carefully and explained thoroughly. Many introductory sections have been rewritten to update them and make them more approachable for students. Whenever possible, illustrations have been added or modified to help students visualize the physical concepts.
The emphasis continues to be on chemical reactivity. Chemical reactions are introduced as soon as possible, and each functional group is considered in view of its reactivity toward electrophiles, nucleophiles, oxidants, reductants, and other reagents. "Electronpushing" mechanisms are stressed throughout as a means of explaining and predicting this reactivity. Structural concepts such as stereochemistry and spectroscopy are thoroughly treated as useful techniques that enhance the fundamental study of chemical reactivity.
This book maintains the traditional organization that concentrates on one functional group at a time while comparing and contrasting the reactivity of different functional groups. Reactions are emphasized, beginning with Lewis acid-base reactions in Chapter 1, continuing with thermodynamics and kinetics in Chapter 4, and covering most of the important substitution, addition, and elimination reactions in the three chapters following stereochemistry.
Spectroscopic techniques JR, MS, and NMR) are covered in Chapters 12 and 13, so that they can be included in the first semester. This early coverage is needed to allow effective use of spectroscopy in the laboratory. Still, a large amount of organic chemistry has been covered before this digression into structure determination. The principles of spectroscopy are practiced and reinforced in later chapters, where the characteristic spectral features of each functional group are summarized and reinforced by practice problems.
Flexibility of Coverage
No two instructors teach organic chemistry exactly the same way. This book covers all the fundamental topics in detail, building each new concept on those that come before. Many topics may be given more or less emphasis at the discretion of the instructor. Examples of these topics are 13C NMR spectroscopy, ultraviolet spectroscopy, conservation of orbital symmetry, nucleic acids, and the special topics chapters: lipids and synthetic polymers.
Another area of flexibility is in the problems. The wide-ranging problem sets review the material from several viewpoints, and more study problems are provided than most students are able to complete. This large variety allows the instructor to select the most appropriate problems for the individual course.
In addition to the classical reactions, this book covers many techniques and reactions that have more recently gained wide use among practicing chemists. Molecular-orbital theory is introduced early and used to explain electronic effects in conjugated and aromatic systems, pericyclic reactions, and ultraviolet spectroscopy. Carbon-13 NMR spectroscopy is treated as the routine tool it has become in most research laboratories. Many of the newer synthetic techniques are also included, such as asymmetric hydrogenation and epoxidation, use of LDA, Birch reduction. Swern oxidations, alkylation of 1,3-dithianes, and oxidations using pyridinium chlorochromate.
Reaction mechanisms are important in all areas of organic chemistry, but they are difficult for many students. Students fall into the trap of memorizing a mechanism while not understanding why it proceeds as it does. This book stresses the principles used to predict mechanisms. Problem-solving sections develop basic techniques for approaching mechanism problems, and they work to minimize rote memorization. These techniques emphasize deciding whether the reaction is acidic, basic, or free radical in nature, then breaking it down into Lewis acid-base interactions and using "electron pushing arrows" to illustrate these individual steps. Important mechanisms are highlighted by placing them in the Mechanism and Key Mechanism boxes.
Introduction to Mechanisms Using Free-Radical Halogenation
The advantages and disadvantages of using free-radical halogenation to introduce reaction mechanisms have been debated for many years. The principal objection to free-radical halogenation is that it is not a useful synthetic reaction. But useful reactions such as nucleophilic substitution and additions to alkenes are complicated by participation of the solvent and other effects. Gas-phase free-radical halogenation allows a clearer treatment of kinetics and thermodynamics, as long as its disadvantages as a synthetic reaction are carefully discussed and the student is aware of the limitations.
Organic synthesis is stressed throughout this book, with progressive discussions of the process involved in developing a synthesis. Retrosynthetic analysis is emphasized, and the student learns to work backward from the target compound and forward from the starting materials to find a common intermediate.
Typical yields have been provided for many synthetic reactions, although I hope students will not misuse these numbers. Too often students consider the yield of a reaction to be a fixed characteristic just as the melting point of a compound is fixed. In practice, many factors affect product yields, and literature values for apparently similar reactions often differ by a factor of 2 or more. The yields given in this book are typical yields that a good student with excellent technique might obtain.
Spectroscopy is one of the most important tools of the organic chemist. This book develops the theory for each type of spectroscopy and then discusses the characteristic spectral features. The most useful and dependable characteristics are summarized into a small number of rules of thumb that allow the student to interpret most spectra without looking up or memorizing large tables of data. For reference use, extensive tables of NMR and IR data and a more complete version of the Woodward-Fieser rules for UV are provided as appendices.
This approach is particularly effective with IR and NMR spectroscopy, and with mass spectrometry. Practical rules are given to help students see what information is available in the spectrum and what spectral characteristics usually correspond to what structural features. Sample problems show how the information from various spectra is combined to propose a structure. The emphasis is on helping students develop an intuitive feel for using spectroscopy to solve structural problems.
IUPAC nomenclature is stressed throughout the book, but common nomenclature is also discussed and used to develop students' familiarity. Teaching only the IUPAC nomenclature might be justifiable in theory, but such an approach would handicap students in their further study and use of the literature. Much of the literature of chemistry, biology, and medicine uses common names such as methyl ethyl ketone, isovaleric acid, methyl t-butyl ether, y-aminobutyric acid, and s-caprolactam. This book emphasizes why systemic nomenclature is often preferred, yet it encourages familiarity with common names as well.
I've enjoyed working on this new edition, and I hope that it is an improved fine-tuning of the fourth edition. I've tried to make this book as error-free as possible, but I'm sure some errors have slipped by. If you find errors, or have suggestions about how the book might be made better, please let me know (L. G. Wade, Whitman College, Walla Walla, WA, 99362; E-mail firstname.lastname@example.org). Errors can be fixed quickly in the next printing. I've already started a file of possible changes and improvements for the sixth edition, and I hope many of the current users will contribute suggestions to this file. I hope this book makes your job easier and helps more of your students to succeed. That's the most important reason why I wrote it.
Instructor's Resource CD-ROM (0-13-0604496). An instructor CD that contains almost all the art from the text, 42 animations, and 135 tutorials. Using the included MediaPortfolio software, instructors can browse for figures and other media elements by thumbnail and description, as well as search by key word or title. In addition, all of the Student Tutorials available on the Companion Website are available on the IRCD as well. The images and videos can be cut and pasted, or dragged into your MS PowerPoint® lecture presentation or other documents. The set also contains two different prebuilt PowerPoint® Presentations for every chapter, all images in .PDF format, as well as all the responsive media elements specifically developed for Organic Chemistry, Fifth Edition.
Transparency Pack (0-13-033836-2). This package comprises 250 four-color acetates of the most useful images, computer art, and line drawings from the text. The Transparency Pack is available at no charge to adopters of Organic Chemistry, Fifth Edition.
Test Item File (0-13-033833-8) by Gary Hopis, Roanoke College, is a printed version of all questions found on the TestGen-EQ software. The new Fifth Edition contains over 1800 questions, including 20% new questions with varied levels of difficulty.
TestGen-EQ (0-13-033834-6). This computerized version of the Test Item File included electronic versions of all 1800+ test questions. TestGen-EQ allows you to create and tailor exams to your own needs and includes tools for course management, algorithmic question generation, and administering tests over a local area network.
Course Management Options. Combine the assets of the Companion Website and the Test Item File for Wade Se with the power of full customization and the functionality of a robust course management system. Course management systems include an online gradebook, discussion forums and bulletin boards, document upload and download areas, and other features. Prentice Hall offers full courses, matched to the book, suitable for a variety of platforms:
- CourseCompass Powered by Blackboard, CourseCompass is-a nationally hosted alternative to a university-licensed course management platform. CourseCompass is designed to be accessible to the novice, but also contains even more power tools than are available in a standard B1ackBoard course, such as full integration with TestGen test creation software.
From the Back Cover
In a highly accessible fashion, this top-selling book bridges the gap between conceptual understanding and actual application—while strongly emphasizing the development of problem-solving skills. The book focuses on traditional organic chemistry topics and offers up-to-date aspects of spectroscopy, relevant photographs, and many applications to polymer chemistry integrated throughout the book.
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