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Book Review Transition Metals in Total Synthesis. By P. J. Harrington

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For example, C,S-C, stands for benzothiophene, C,S-C,C, for naphthothiophene, and so on. In any case, this is then
followed by the structural formula, the name, and details of
synthesis, occurrence, and properties. In each case the data
are supported by the names of the authors and the year of
publication. The full citation can be found in a special chapter containing nearly 1000 references, arranged alphabetically by authors. There is also an index containing about
900 keywords relating to the thiaarenes listed.
One might criticize by pointing out that, despite the wealth
of material, only a modest amount of information on mutagenic and carcinogenic properties is given, and that the
manuscript deadline was apparently as early as 1986. Nevertheless, the monograph is an essential first step, and it provides a sound basis for a deeper understanding of the possible environmental effects of sulfur-containing polycyclic
arenes and an initial attempt at a comparative study. At the
same time it also reveals the disturbing inadequacy of our
knowledge of this specialized topic, but on the other hand it
points the way to future work, including especially computer-aided molecular modeling studies. Although this is an
unconventional book, it can be recommended for everyone
interested in the subject.
Roland Muyer
Institut fur Organische Chemie
der Technischen Universitat Dresden (FRG)
Transition Metals in Total Synthesis. By P..
I
Harrington.
Wiley, Chichester, 1990. xvi, 484 pp., hardcover E 47.50.ISBN 0-471-61300-2
The very welcome aim of this book is to demonstrate the
value of proven synthetic methods based on organotransition-metal chemistry, by exemplifying their application to
key steps in total syntheses. The author states in the preface
that it is intended for advanced students as well as experienced chemists.
The well-bound book, whose clean, well-set text contrasts
to some extent with the rather unprofessional looking structural formulas, consists of 14 chapters and is provided with
a subject index. Each chapter is linked to one or two structurally related target compounds and usually starts with an
explanation of their origin and biological activity. This is
always followed by a quite detailed description of a certain
class of organotransition-metal compounds, covering methods of preparation and typical reactivities. The chapters conclude with a tersely presented (“synform-like”) total synthesis of the target molecule(s) in which the previously discussed
organometallic compounds are involved in key positions.
In this manner, the book describes a rather limited, but
quite relevant selection of synthetically useful methods for
C-C-bond formation, in all of which transition-metal complexes are used either as catalysts (e.g. Heck reaction, allylic
alkylation, Stille coupling, Vollhardt cyclization), stoichiometric reagents (e.g. Pauson-Khand reaction, Tebbe-Grubbs
reactions, Schwartz reaction) or building blocks (e.g. reactions at carbonyl n complexes of Cr, Fe or Co, or the Dotz
reaction).
Upon first glance the book makes a favorable impression.
It is at once evident that the author made an effort to give the
reader a broad overview with the emphasis on the preparative scope of each method. In this he can be excused for
occasionally resorting to mere lists, and not even flinching
from including ten-page tables. However, in the likewise very
detailed explanations of mechanisms it would have been deAnZen>.Chrm. Inr. Ed. Engl. 31 (1992) No. 3
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sirable to put a greater emphasis on the basic and common
principles of organotransition-metal reactions.
One ground for criticism is the rather frequent mistakes in
structural formulas (for example, on page 210 alone, four of
the twelve formulas contain a total of six errors); there are
the contracted C-rings of two steroids (page 233), the apparently epimerized 17-P-estradiol (page 202), the inadvertently
partially hydrogenated arene (page 212), and a product with
a shifted methoxy group (page 331). Also the denotation of
nonisolable intermediates by square brackets is not applied
consistently, which leads to confusion, as too does the fact
that in many of the formulas the (relative) stereochemistry is
not fully indicated or (sometimes) not given at all.
Apropos stereochemistry : It is unfortunate that in this
book little or no distinction is made between absolute and
relative configuration. Even the target compounds (with biological activity) are usually introduced as racemates (e.g.
(f)-estrone on page 200), and the chosen syntheses then
lead likewise to racemic mixtures. Thus, readers who regard
the control of absolute configuration as an important objective as well might not be completely convinced of the usefulness of organotransition-metal methods. The term “enantioselectivity” does in fact appear in one of the chapters, but not
in the context of a synthesis, and characteristically, of the
“chiral” ligands shown there (pp. 74-75) at least two are
(according to the formula diagram) meso compounds. That
stereochemistry is not exactly the author’s favorite topic becomes especially apparent in Chapter 1 1 , where arene tricarbonylchromium complexes are discussed. After convincing
the reader that compounds of this type can be chiral, the
author states (on page 337): “To illustrate, complexation of
racemic 1-indanol can produce as many as four diastereomers.
In fact, complexation occurs exclusively on the same face as
the hydroxyl group. The pair of diastereoisomeric complexes
are separable. Oxidation of the (S)-isomer affords a single
complex of indanone”. This statement is quite simply wrong
at several points. It ought to read: “... as many as four
stereoisomers (two diastereomeric pairs of enantiomers). In
fact, complexation occurs diastereoselectivity on the same
face as the hydroxyl group. The pair of enantiomeric complexes may be separated by classical resolution techniques
(via diastereomer formation). Oxidation of the (1 S)-isomer.. .”.
There are also other errors that do not exactly inspire
confidence, for example, the conversion of a ketone to an
epoxide by using the dimsyl anion (p. 140), or the (improbable) occurrence of free cyclobutadiene as an intermediate in
the preparation of its Fe(CO), complex from 3,4-dichlorocyclobutene (p. 98).
The currentness of the book leaves something to be desired as well. Although there are a handful of literature references for 1987 (mostly to the author’s own work) and 1988,
the discussions are, on average, considerably less up-to-date
than this. Had the author taken the trouble to research the
more recent literature, it would have saved him several further embarrassments. For example, it is regrettable that in
discussing the Semmelhack syntheses of ( f)-acorenone and
(+)-acorenone B (Chapter 11) he has failed to mention the
work of Uemura etal., which was published in 1986. In
stating that “stereospecific synthesis of (intermediates) A
and B would improve both syntheses significantly” (p. 343)
he reveals his ignorance, as exactly this problem has already
been solved by Uemura. In another passage (pp. 318-319)
he describes how complexes of benzene derivatives with Cr(CO), can be prepared by transcomplexation at 200°C; here
we read: “Thus, the naphthalene complex should be most
suitable for preparation of new arene complexes by arene
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365
exchange”. It is almost beyond belief that the method introduced several years ago by Kiindig and since applied by
others, which does in fact use the naphthalene complex as the
reagent (at mild 70 “C), is not cited here.
Though the book’s flaws are flagrant, its strengths should
not be completely ignored. Many of the chapters are quite
readable, interesting, and well written from a teaching standpoint. Doubts remain, however, that the author can convince a wider circle of readers of the usefulness of organotransition metal methods, since almost no comparisons with
alternative methods of synthesis are made. And when the
low cost of a starting material (e.g. 2-methylanisole) is put
forward as a “selling point” for a particular synthesis, many
readers will be annoyed to discover that the cost of the transition metal reagent required in stoichiometric quantities is
many times greater, but not even mentioned. Instead, so
many thoroughly sound arguments and good examples
could have been put forward as impressive confirmation of
the usefulness of transition metals for total syntheses-ven
for nonracemic target compounds.
To summarize, the author’s intentions are entirely laudable, but the value of the book is considerably diminished by
the many shortcomings as regards the quality and up-todateness of the discussions. Readers who use the book for
casual browsing will certainly be able to derive some interesting ideas and insights from it. On the other hand, those
looking for a good treatment of the applications of transition
metals in organic synthesis, especially beginners in the field,
would be better advised to go to other (and also cheaper)
monographs, such as that by Collman, Hegedus, Norton,
and Finke and/or to a selection of recent review articles on
the individual topics. The gap in the market, which this book
was intended to fill, remains open.
Hans-Giinther Schmalz
Institut fur Organische Chemie
der Universitat Frankfurt/Main (FRG)
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Angew. Chem. Inf. Ed. Engl. 31 (1992) No. 3
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