Chemical Education Today
Book & Media Reviews
Organic Chemistry: An Intermediate Text Robert V. Hoffman. Oxford University Press: New York, 1997. xii + 322 pp. Figs. and tables. 16.9 × 24.2 cm. ISBN: 0 1950 9618 5. $49.95.
This compact new book is the second in a developing Oxford series, Topics in Organic Chemistry. It is designed as a primary foundation text for an advanced undergraduate–first year graduate course and contains eleven chapters: Functional Groups and Chemical Bonding; Oxidation States of Organic Compounds; Acidity and Basicity; Curved-Arrow Notation; Stereochemistry and Conformation; Functional Group Synthesis; Carbon–Carbon Bond Formation between Nucleophiles and Electrophiles; Carbon–Carbon Bond Formation by Nonpolar Reactions; Free Radicals and Cycloadditions; Planning Organic Syntheses; Mechanisms of Organic Reactions; and Structure Determination of Organic Compounds. These are arranged in a logical sequence and range in size from 8 (Oxidation States) to 52 pages (Structure Determination). Each chapter is subdivided into sections and ends with a short bibliography citing common sophomore or more advanced texts and review articles. A collection of from 2 to 13 problems concludes each chapter, although most of these have multiple parts so the actual number of problems is substantial. The is also a 10-page index. The font is small but readable. Each page is dense with text or figures, most of which are expertly rendered. The text itself is clean and crisp with relatively few typographical or grammatical errors, although some of these, such as the use of “quantitate” (p 40), are unfortunate. In some cases, the molecules shown are not named but arbitrarily given letter designations. This seems unnecessary and confusing—particularly in Chapter 9, where the letter “P” is used to designate two different synthetic targets. Kekulé and bond line structures are used interchangeably, requiring a high level of student comfort with these representations. Written from a mechanistic and structural perspective, this book is meant to fill the glaring vacuum that exists for a concise, one-semester, advanced undergraduate text and to provide sufficient review to serve as a bridge into graduate-level material. In general, it succeeds admirably. The size, layout, and coverage remind one of the similarly titled monograph by J. Stowell (see review of the second edition, J. Chem. Educ. 1995, 72, A37). However, there are some differences. The Hoffman text omits sections on nomenclature and literature searching, the synthesis examples are not taken from published total syntheses, and none of the text examples or problems are referenced, although some of these clearly derive from primary literature. The individual chapters vary in length and depth. For example, the description of functional group transformations in Chapter 6 is insightful and modern, discussing the Barton, Mukaiyama, and Peterson reactions in addition to the rhodium-catalyzed formation and utilization of carbenoids from diazo precursors. However, there is no discussion of other important processes such as the Sharpless reaction. The 34
modern variation of the Wolff–Kishner reaction is not mentioned (p 130), nor is the alternative ylid mechanism of the Swern oxidation (p 119). Occasionally the coverage is incomplete. For example, for the Peterson reaction only the stereochemistry under basic conditions—not acidic conditions— is discussed (p 129). Similarly, in Chapter 7, the greater electrophilicity of aldehydes over ketones is rationalized on steric but not electronic grounds (p 142). Baldwin’s rules are not mentioned within a broad discussion of ring closure in Chapter 8. The Nef reaction is shown as a synthetic strategy in Chapter 9 but not explicitly named (p 204). The NMR section in Chapter 11 starts with fundamental material and proceeds to second order spin systems but excludes 2-D techniques. While it offers a succinct discussion of complex splitting patterns, nonetheless some confusion may be engendered by the indication that the C-2 methylene hydrogens in phenyl-n-propyl ether appear as a sextet (p 269). Also, inexplicably, the 13C NMR spectrum of buckminsterfullerene is said to show two lines, not one (p 285). There are a few other substantive errors. The statement that bonding and antibonding molecular orbitals are energetically symmetric below and above the precursor AO energy levels is incorrect (p 13). A drawing of the tub conformation of COT is mislabeled as being antiaromatic (p 20). The cyclohexadienyl intermediate in electrophilic aromatic substitution—referred to as the Wheland intermediate, an infrequently used descriptor—has the charge resonance distributed over three, not five, of the ring atoms (p 64). Radical addition to alkenes is incorrectly portrayed as occurring on the bonding (π) orbital (p 178) and the Diels–Alder cycloaddition is twice shown as proceeding via a HOMO-LOMO interaction (pp 181 and 184). There are also some omissions. Anhydrides, lactones, lactams, and isocyanates are absent from the otherwise useful summary listing of important functional groups with which the book opens (p 3). While the MO energy level diagrams for the butadienyl, benzene, tropylium and cyclooctatetraene systems are briefly given, the complete pictorial array of molecular orbital symmetries is not explicitly shown (pp 20–21). Stereochemistry is stressed throughout but the derivation of R and S configurations from Fischer projection is not explicit; nor is it clearly stated that, in enantiomers, all of the stereocenters switch configuration. Despite an emphasis on the importance of reactivity matching—which is mentioned three times in Chapter 7, often quite humorously—this core concept is not clearly defined. In these instances, the author seems obligated to present basic material while at the same time, assuming it is familiar, is eager to move on. In Chapter 8, the only cycloaddition reactions presented are the familiar [2+4] Diels–Alder and the 1,3-dipolar variant. Both sigmatropic and electrocyclic processes are unfortunately excluded, the emphasis being placed on a detailed discussion of radical addition, reduction, cyclization, and polymerization reactions. Finally, it would have been helpful to have included a table of bond dissociation energies. Overall, however, these
Journal of Chemical Education • Vol. 75 No. 1 January 1998 • JChemEd.chem.wisc.edu
Chemical Education Today edited by
Edward J. Walsh Allegheny College Meadville, PA 16335
are all correctable and thus relatively minor points. The strengths of this book include a cogent and perceptive discussion of acid–base chemistry and a thematic emphasis on electron flow. This is highlighted early in Chapter 4, which expertly details the principles and use of electron movement to explicate reactivity, describe resonance, and depict mechanism. In Chapter 3, oxidation states are stressed as an additional, useful way to understand reactivity, assess bonding changes, and facilitate correct reagent choice. Thus three broad mechanistic models are utilized: the curved arrow, oxidation state changes, and molecular orbital theory. While each of these is appropriately used, some examples might benefit from a more integrated approach. An MO picture of the SN2 process showing the σ antibonding acceptor orbital would be illuminating (pp 61, 141), as would a representation of the carbonyl antibonding π orbital (p 142). The weaknesses of this text include an apparent lack of relevance in the examples chosen, the only exception being the brief mention of a synthesis of testosterone acetate (p 212), and the absence of citations to primary references; this makes the examples and problems more academic than need be. Although numerous illustrative reactions are presented, these are not linked to the research process by which new organic chemistry is discovered and the routes by which it is disseminated. This obviates direct access to the literature and
unfortunately does little to encourage the advanced student to follow up on the text examples, check procedures, or learn to read and interpret primary sources. The overall utility of this text derives from its readability, timeliness, breadth, and thematic focus and the sense of completion it provides. The author presents a perceptive and up-to-date discussion of nearly all topics one would want included in an abbreviated, advanced course. As such it complements the longer texts by Carey and Sundberg, Lowry and Richardson, and March and Warren. Furthermore, unlike many texts, Hoffman’s offers a coherent theme: the development of reactivity from the central concepts of bond strength, polarity, acidity, charge development and stabilization, electron movement, and transition state structure; and it shows how these can be employed to elucidate a complete mechanistic description. While necessarily idiosyncratic, the topics chosen are insightfully presented and those that are covered less than completely can be supplemented by journal articles and can form the basis for further class discussion. In summary, this is a thoughtful text and a welcome contribution certainly suited for its designed purpose. Alan M. Rosan Drew University Madison, NJ 07940
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