STRUCTURE AND MOTIF
Too many students find that organic chemistry is an overwhelming parade of facts. Our goals are to dispel this notion and, more importantly, to help students learn and understand organic chemistry. The best way to do this is to provide a framework, or scaffolding, around which students can organize their thoughts. The framework that we provide is the accessible notion that understanding structure will lead to an understanding of function.
A Uniform Organization Emphasizes the Relation Between Structure and Function
Much like a language, in which grammar would be dangling without the "meat" of vocabulary, the text develops material as a juxtaposition of structure and function. Thus, Chapter 1 provides the fundamentals of structure and bonding, specifically as they will become useful in understanding organic chemistry. Chapter 2 then follows with an introduction to the structural features of the alkanes and how they "function" in the simplest sense, namely, conformational mobility. Chapter 3 relates bond-dissociation energies to the lead reaction: radical halogenation (functionalization) of alkanes. Chapter 4 repeats the motif of Chapter 2 but has cycloalkanes as the center of focus.
The structure of the haloalkanes and how it determines their fate in nucleophilic substitution and elimination reactions are the topics of Chapters 6 and 7. Each subsequent functional group is covered according to the same rhythm: naming, structure, spectroscopy, preparations, reactions, and biological and other applications.
Students Are Given the Structural "Tools" They Need to Understand Function
The interplay between structure and function that gives a hierarchy to individual chapters also confers a hierarchy on the text as a whole. This is why we introduce stereochemistry in Chapter 5. Students learn about stereochemical principles so that they are prepared to understand the substitution and elimination reactions of haloalkanes (Chapters 6 and 7) and the addition reactions of alkenes (Chapter 12). Moreover, this hierarchy allows the mechanistic discussion of all new important reactions to take place concurrently rather than being scattered in different places throughout the text. Such a unified presentation of mechanisms benefits the student enormously.
Alcohols (Chapters 8 and 9) with the simplest oxygen-containing function are treated early because their chemistry sets the stage for understanding their central role in synthesis. Similarly, carbocations (and their rearrangements, Section 9-3) appear before a discussion of the Markovnikov rule, alkenes (Chapter 12) before conjugated polyenes (chapter 14), and conjugated polyenes before aromatic systems.
Early Presentation of Spectroscopy
Our first edition broke ground by introducing spectroscopy right after alcohol chemistry. Early coverage, beginning with NMR in Chapter 10, offers opportunities to practice the application of spectroscopic methods to many kinds of compounds. After NMR, we cover IR and UV-visible spectroscopy in Chapters 11 and 14 in the context of functional groups. Courses can include each of the principal types of spectroscopy in the first half of the text.
The Lead Reaction: Radical Halogenation of Methane
The first, more detailed discussion of a reaction and its mechanism, the "lead reaction", is presented very early in Chapter 3. For several reasons, the best (most logical) choice is the chlorination of methane. First, all chemical reactions require bond-making and bond-breaking. The radical halogenation of methane allows the introduction of the concepts of bond-dissociation energies and the stability and structure of the ensuing radicals. This leads to an understanding of the thermal stability of the simplest organic bonds, C-H and C-C, and, hence, of why organic materials are capable of existence. The students learn that to "activate" a C-H bond, a reactive agent is required. Second, the lead reaction, because it purposely does not include ionic species, can be analyzed thermodynamically by calculating enthalpies of the overall process, as well as individual steps. This exercise is fundamental and gives the student the basic tool of "eyeballing" the relative feasibility of all future transformations. It also serves as a first application of potential energy diagrams to a chemical process. Third, the generalization of the chlorination of methane to the halogenation of other alkanes permits the simple introduction of the concepts of reactivity and selectivity, a feeling of the statistics needed to deal with molecules endowed with several equally reactive sites, and practical applications of these principles.
Emphasis on Synthetic Strategy
The importance of synthesis is stressed starting on page 3, and the considerations entering into the development of a good synthetic strategy and the avoidance of pitfalls are developed throughout the text. Since the innovative introduction of Section 8-9 on retrosynthetic analysis in the first edition, this aspect of the text has received much positive feedback from teachers and students. The present edition has added a slightly more explicit treatment of linear versus convergent synthesis to this section. Multistep partial and total syntheses are pointed out where appropriate in the various functional-group treatments. Particular emphasis is placed on stereo- and regioselectivity (Chapter 12 and Section 16-5), biological and medicinal relevance (e.g., Sections 9-11, 12-16, 18-12, and 19-4, and Chapters 24 through 26), and the importance of materials synthesis (e.g., Sections 12-13 through 15, 13-11, 14-10, and 21-12). These discussions are then extensively reinforced in the In-Chapter Exercises and End-of-Chapter Problems and highlighted in numerous Chemical Highlights.
Modern Coverage
Modern developments at the forefront of current research have been included in the main body of the text or in Chemical Highlights, in particular enantioselectivity, advances in molecular biology (e.g., structure recognition), medicine (drugs), and progress in materials science.
Rigorous (IUPAC and Chemical Abstracts) nomenclature is used whenever possible, and common names are added in parentheses when warranted. The reactions presented in the text are (with minor exceptions) drawn from the original literature with actual conditions and yields.
We recorded authentic spectra on modern computerized equipment. We have incorporated 300 MHZ and higher frequency 1H NMR spectra to demonstrate the higher resolution at such field strengths and, when necessary, to simplify the spectral patterns of compounds that produce overlapping signals at lower fields. We have retained 90 MHZ as the resonance frequency for molecules that exhibit first order behavior under these conditions, because the reproduction of their spectra is clearer, is easier to read, and does not require the use of expanded inserts.
Emphasis on Problem Solving and Tools for Studying
In-chapter Exercises provide immediate reinforcement of concepts as they are presented. All Exercises are answered at the back of the book. More than 750 end-of-chapter problems give students additional practice in problem-solving skills.
Chapters conclude with summaries of New Reactions and Important Concepts.
TOP
NEW FEATURES OF THE THIRD EDITION
All chapters have been revised and updated. Text has been clarified, simplified, and corrected in accord with new literature and the comments of reviewers and students. Structural drawings have been carefully scrutinized for consistent and accurate representation, and many condensed formulas and Fischer projects have been replaced by line structures. We have also reviewed the use of color in reaction schemes.
New Chapter Introductions
The introduction to each chapter has been "spiced up" with thought provoking questions relating the relevance of the chapter's material to everyday experience. These general questions find an answer on further reading, thus prompting the students' interest and participation.
Improved Presentation of Reaction Mechanisms
The presentation of reaction mechanisms has been improved by the increased use of arrows to better show electron flow. The introduction of icons for a "reaction" and its "mechanism" serves to emphasize the "vocabulary-grammar" duality of the two types of schemes. In addition we have added a new section one electron-pushing arrows (Section 6-4) to familiarize the student explicitly with this technique.
Early Coverage of Acids and Bases
We have moved the discussion of acids and bases to Section 2-9 and expanded it to provide the student with an early review of this aspect of general chemistry as it applies to organic systems. This treatment now includes explicitly Lewis acids and bases and sets the student up for a general understanding of the similarity between such diverse processes as nucleophilic trapping of carbocations, solvation (e.g., of Grignard reagents or by crown ethers or ionophores), and for the role of metal halides in Friedel-Crafts alkanoylation.
Unified View of Spectroscopy
We have added problems that unify the application of spectroscopy techniques in structure elucidation.
New Approaches to Problem-Solving
New Chapter Integration Problems are solved problems that emphasize concept integration both within and between chapters. The solution is worked out in a step-by-step manner, teaching the art of problem solving in general and specifically demonstrating how one set of learned skills builds on and interacts with preceding ones. Particular emphasis is placed on problem analysis, deductive reasoning, and logical conclusions.
The Team Problem is also new to each chapter. Team Problems encourage discussion and collaborative learning among students.
Students who are planning careers in medicine will appreciate the new Preprofessional multiple-choice problems that are typical of those that appear on the MCAT exam.
Reaction Summary Road Maps
From Chapter 8 onward, the chemistry of each functional group is shown in condensed form through two types of reaction summary road maps, providing "the functional group at a glance." The first type depicts the function as the origin of multiple reaction arrows, each labeled with a particular reagent, ending in a specific product. Section numbers indicate where the transformation is discussed in the text, and color distinguishes past from future chemistry. This map provide information about the reactions of the functional group--that is, what it does. The second type of map is very similar, but the reaction arrows are reversed--that is, pointing toward the functionality. This map provides information about the function's possible origins--that is, what are the precursor functional groups. Thus, each specific reaction A->B will appear in two separate schemes, one with A and the other with B as the center. These maps are an important aid in synthetic-retrosynthetic analysis and a check on the student's "vocabulary" of synthetic methodology.
Computer-Generated Ball-and-Stick and Space-Filling Models
The first and second edition emphasized the importance of building molecular models as an aid in visualizing three-dimensional structure and dynamics. We have highlighted this emphasis by a third icon at numerous locations. In addition, we have now included pictures of ball-and-stick and of space-filling models, as appropriate, generated by computer with the use of the Spartan program. These pictures serve to encourage students to play with actual models and to reinforce their use. They provide the students with lowest-energy conformations, guiding them in the construction of realistic assemblies. Finally, space-filling renditions create a more accurate impression of size, shape, and the extent of orbitals. Maruzen Ball-and-Stick and Space-Filling Molecular Structure Sets are available for purchase through the publisher.
TOP
SUPPLEMENTS
The CD-ROM found in the back of each textbook is a multimedia learning tool developed by W. H. Freeman and Company in conjunction with Sumanas, Inc. All the features of the CD function within the context of the book's coverage. All the structures mentioned in the book are depicted as three-dimensional animations with multiple-display options through a molecular-modeling program. These animations and many other molecular-level simulations bring the concepts of the book to life. Practice tools, such as interactive quizzes in every chapter and a preprofessional examination, help students review for exams. Interactive sample problems and solutions help guide students through difficult concepts. WebNotes provides direct links to relevant chemistry sites on the World Wide Web. Presentation software for instructors allows them to prepare series of illustrations and animations for lecture.
The Study Guide is again written by Neil Schore. The Study Guide summarizes each chapter from a different perspective from that of the text. Sample problems are worked out, and the solutions to the end-of-chapter problems are given. Hints to the Student sections point out pitfalls of faulty logic and help those who find it hard to visualize the solution steps for various exercises. Tables conveniently summarize the spectral features associated with each functional group. A glossary of key terms also is provided.
Overhead Transparencies are available from the publisher to aid instructors in lecture presentations. This selection of illustrations from the text follows the functional use of color in reproductions of spectra, orbitals, diagrams, and mechanisms.
The Test Bank by Charles M. Garner and Kevin Pinney of Baylor University is new to this edition. With the Windows and Macintosh software of the computerized versions, instructors can easily change and add questions as well as import their own electronic drawings.
The Maruzen Molecular Structure Model set is also available for student purchase. This essential tool can be used to present orbitals; single, double, and triple bonds; and locations of atoms.
We use color consistently and functionally to help students master basic principles, including nomenclature, orbitals, sequence rules in stereochemistry, the relation of spectral lines to functional groups, topological changes in molecular transformations, and the reactivity of functional groups. Color is suspended in exercises, chapter reviews, and problems, however, because it is important to learn how not to rely on it. In this edition, we have carefully reevaluated the application of color in reaction schemes and simplified its use. We also added many marginal notes as reminders of color designations in various transformations.
For example, wherever possible, s orbitals are shown in red, 2p orbitals in blue, spn hybrids in purple, and 3p orbitals in green.
Color shows the relation of the names of organic molecules to their structures. The functional group that gives the molecule its unique chemical behavior and other substituents are each differentiated from the stem by color so as to match the corresponding components of the name itself. In the illustration shown here, which is from Chapter 11, the student can more easily remember, for example, that the double bond shown in red gives the name of the molecule its characteristic -ene ending.
Color is used to associate spectral features with certain molecular units. For example, in the adjoining spectrum, the three colors show how the three nonequivalent hydrogens give rise to three distinct "peaks"--an observation that will help the students identify a molecule when they know its spectrum.
Color offers clues to a molecule's stereochemistry, or the arrangement of its atoms in space. The student will see in Chapter 5 that substituents in three dimensions can be assigned a priority according to certain "sequence rules," and this assignment has been indicated, in diminishing order of priority, by red, blue, green, and black.
Most importantly, color frequently shows how the functional groups transform in the reaction mechanism. Electron-rich, or "nucleophilic," parts are shown in red; electron-deficient, or "electrophilic," fragments are blue; and radicals and leaving groups are green. Red arrows in these transformations indicate the movements of electrons.
TOP
Vollhardt & Schore, Organic Chemistry: Structure and Function, 3rd Edition, 1998
W. H. Freeman & Co. and Sumanas, Inc.