|
Oxford University Press: New
York, 1997. xii + 322 pp. Figs. and tables. 16.9
x 24.2 cm. ISBN: 0195096185. $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
undergraduatefirst 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; CarbonCarbon Bond Formation between
Nucleophiles and Electrophiles; CarbonCarbon 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 modern variation of the WolffKishner
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 (pi) orbital (p 178) and the DielsAlder
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
2021). 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] DielsAlder 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 are all correctable and thus relatively minor points.
The strengths of this book include a cogent and
perceptive discussion of acidbase 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
sigma antibonding acceptor orbital would be illuminating (pp 61, 141), as would
a representation of the carbonyl antibonding pi 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.
|