close

Вход

Забыли?

вход по аккаунту

?

Book Review Catalytic Chemistry. By B. Gates

код для вставкиСкачать
of progress reports. R. W. Franck deals with the use of
dienophiles derived from carbohydrates, describing cycloadditions involving both electron-rich and electron-deficient
dienophiles. The preparation of cl,p-unsaturated aldehydes
and dienes from pyranoses and their use in cycloaddition
reactions is described by J. C. Lopez et al. Such a,p-unsaturated aldehydes can act not only as dienophiles but also as
diene components in hetero-Diels-Alder reactions. The article by M. Chmielewski describes the use of glycals in
[2 + 2]-cycloadditions with isocyanates. The cycloadducts
obtained in this way can serve as educts for the synthesis of
p-lactam derivatives. D. Horton discusses the control of
stereospecificity in the cycloaddition of cyclopentadiene to
a$-unsaturated esters prepared from aldopentoses. Not surprisingly, it is found that the facial selectivity in the cycloaddition reaction is controlled mainly by the allylic substituent.
Y. Leblanc describes the hetero-Diels-Alder reaction of glycals with azodicarboxylates. This proceeds regiospecifically,
yielding heterocyclic adducts that can be used for direct glycosidation with glycosyl acceptors. The effectiveness of this
method has been demonstrated by synthesizing a number of
complex 2-aminosaccharides. In the following article P.
DeShong describes the use of glycosyl-manganese pentacarbony1 complexes for synthesizing C-glycosides. The glycosylmanganese pentacarbonyl complexes for this purpose can
easily be prepared from a glycosyl bromide and a salt of the
manganese pentacarbonyl anion. By means of insertion reactions these complexes can then be converted to C-glycosides
in a wide variety of ways. However, this very interesting
contribution has little relevance to the subject of cycloadditions. That criticism certainly does not apply to the next
article, in which P. Herzegh et al. start by describing how a
thiocarbonyl derivative prepared from a carbohydrate can
undergo a hetero-Diels-Alder reaction with a 1,3-diene to
yield a chiral thiopyran derivative. They then go on to describe intramolecular Diels-Alder reactions in which a diene
and a dienophile are linked through a chain derived from a
sugar, yielding various highly functionalized hexahydroindenes and octahydronaphthalenes. The next article, by H.
Kunz, is concerned with a different application of carbohydrates, namely as chiral auxiliaries. For example, acrylates
derived from carbohydrates can be reacted with 1.3-dienes in
the presence of a Lewis acid catalyst to give the corresponding cycloadducts with a high degree of selectivity. Similarly,
imines prepared from glycosyl amines can be reacted with
electron-rich dienes, again with high selectivity. In all these
cases it appears that the choice of the pivaloyl protecting
group at the positions of the OH groups of the sugar is
crucial. Next A. Lubineau discusses the effect of using water
as the solvent for the Diels-Alder reaction between watersoluble dienes and electron-deficient dienophiles. Typical
dienes that can be used here are 1,3-butadienylethers of carbohydrates without protecting groups. F o r these cycloaddition reactions the endo-selectivity is practically loo%, and
the reaction rates are higher than in the usual organic solvents. In the last article L. Fisera describes 1,3-dipolar cycloadditions in which various nitrones derived from sugar
aldehydes are reacted with N-aryl maleic imides. I feel that
1,3-dipolar cycloadditions could have been given more space
in this book. One important topic, the de-novo synthesis of
carbohydrates by means of cycloadditions, is even omitted
entirely. However, this may have been a deliberate decision,
as there is already a volume on this topic in the ACS Symposium Series.
In summary, this book offers a representative collection of
articles on recent work in the area of cycloaddition reactions
of carbohydrates. In each article the stereochemical aspects
Angmi.. Clwm In[. Ed. Engl. 1993, 32. N o . I I
0 VCH
of the results are discussed in detail using appropriate transition state models. The book includes subject and author
indexes which make it easy to locate a specific topic. However, one can also enjoy simply leafing through the book and
admiring the illustrations. The way in which the book has
come about inevitably means that there is some overlapping
between individual articles. Also some readers may be somewhat displeased by the presentation, as there are differences
in the typefaces used by the individual authors, and the line
spacing is not uniform throughout. Despite this, the book
can be recommended for everyone whose work is concerned
with carbohydrates, cycloadditions, o r stereoselective syntheses in general. It should provide many stimulating new
ideas.
Martin E. Maier
Fakultat fur Chemie
der Universitat Konstanz (FRG)
Catalytic Chemistry. By B. Gates. Wiley, Chichester, 1992.
XXI, 458 pp., paperback E 14.95.--ISBN 0-471-55914-8
The literature on chemical catalysis has up to now suffered
from being divided, according to the catalytic principles
used, into homogeneous and heterogeneous catalysis. Since
it is, to a greater extent than any other area of chemistry, an
interdisciplinary field between pure science and technology,
the recent publication by Wiley of a textbook on “Catalytic
Chemistry” for students and teachers is welcome news. This
conveniently-sized book attempts to cover all the important
aspects of catalysis, a difficult but worthwhile task, even if it
cannot be fully achieved.
The division into chapters is essentially along the lines of
types of catalysts and processes, which is sensible from a
teaching standpoint. Thus the main chapters cover: catalysis
in solutions (Ch. 2, 128 pp.), catalysis by enzymes (Ch. 3,
47 pp.), catalysis by polymers (Ch. 4, 71 pp.), catalysis in
cavities of molecular dimensions (Ch. 5, 55 pp.), and catalysis at surfaces (Ch. 6, 106 pp.). The short first chapter
(14 pp.) introduces some important concepts (amplified
where necessary in a glossary at the end of the book), emphasizes the importance of the mass balance laws and kinetic
relationships (which other textbooks usually neglect), discusses catalytic cycles taking as an example the production
of 1,4-hexadiene by the ethylene- butadiene coupling reaction, and ends with a “Problems Section” aimed at involving
the reader in some learning activity.
The merits of this book are that it gives a quick overview
of the most important types of (industrially relevant) catalytic processes, discusses some problems that remain to be
solved by further research, and frequently compares kinetic
data with mechanistic models and hypotheses. All the important modern catalytic processes are treated and, wherever
possible, discussed in the context of kinetics laws. The reader
interested in the practical details of industrial catalytic processes should find the clearly set out flow schemes especially
useful. The author has incorporated results from recently
published work, and always makes a point of relating the
discussions to practical situations; this is shown, for example, by the description in mechanistic terms of the osmium tetraoxide catalyzed cis-hydroxylation of olefins
(p. 141 f.). Here his wide experience of catalytic research,
particularly in the field of surface organometallic chemistry,
shows up to advantage.
The boldness to attempt a comprehensive treatment, always a good feature in a textbook, inevitably involves the
Verlu~~gesellschufrfr
rnhH, 0-69451 Weinheim, 1993
057U-U833/93/I111-1667 3 1U.UUf .25/0
1667
risk of shortcomings. Three examples of these are the following: 1) Hydroformylation (p. 91 ff.). Although the
Halpern mechanism is shown by formulas, readers (who are
likely to include advanced students of chemistry and process
technology) are not told about the problem of regioselectivity. Consequently there is also no reference to the possibility
of achieving stereoselective hydroformylation of prochiral
olefins. It is pleasing that the highly topical two-phase
hydroformylation process and the Aldox process are included, but there should also have been a brief discussion of the
advantages and disadvantages of some more commonly used
catalysts, such as the Shell and UCC systems. 2) Olefin
metathesis. Leaving aside the fact that Eleuterio (1960) was
not the discoverer of this reaction (it originated much earlier
as a spin-off from work on olefin polymerization), no information is given about catalysts suitable for industrial use.
Also the treatment of the reaction mechanism is dubious
from the standpoint of organometallic chemistry. Here the
description of important industrial processes (e.g., SHOP,
Norsorex, Vestenamer, cf. Kontakte 1991 (3), 29ff.) is quite
unsatisfactory, and consequently this chapter is not convincing. 3) Propene oxidation (p. 403 ff.). The essentials of
bimetallic catalysis, of which the Sohio process for the
ammoxidation of propene is an important industrial example, are well described. However, although the discussion
of the mechanism is up-to-date so far as the (meager) literature is concerned, it fails to convey a picture of the molecular
reaction steps that might be involved. Here there was a good
opportunity to relate heterogeneously catalyzed processes to
organometallic model systems!
This book may well provide the advanced student of
chemistry with an impression of the wide-ranging nature of
chemical catalysis, but this is achieved at the cost of superficiality in some important areas. I therefore feel that work
using this book needs to be accompanied. or still better preceded, by a good lecture course providing a thorough
grounding in the fundamentals. Under these circumstances it
would prove its worth, since a lecture course cannot include
the same amount of detail on reaction kinetics and process
technology. Thus the book can be recommended to everyone
who has to spend a period of time concentrating on the study
of catalytic chemistry and, as a chemist o r chemical engineer
in industry, needs to read up on the subject to extend or
refresh his or her knowledge. The book is well worth its
price.
Wolfgang A . Herrmann
Anorganisch-chemisches Institut
der Technischen Universitat Miinchen
Garching (FRG)
Accurate Molecular Structures. Their Determination and Importance. (Series: TUCr Monographs on Crystallography,
Vol. 1.) Edited by A . Domenicano and I . Hargittai. International Union of Crystallography, Oxford university
Press, Oxford, 1992. XXT, 590 pp., hardcover 5 60.00.ISBN 0-1 9-855556-3
With this book the International Union of Crystallography (IUCr) begins a series in which various special areas of
crystallography will be treated in detail. However, rather
than limiting the series strictly to crystallography, the editors
(A. Domenicano and I. Hargittai) are sensibly extending the
scope so as to acquaint readers with other methods of structure determination and their applications.
The determination and interpretation of the structures of
molecules is an important area of chemical research, which
is also interdisciplinary. To carry it out effectively it is essential to have a knowledge of the accuracy and limitations of
the methods with regard to systematic and random experimental errors. This book summarizes the capabilities of the
various methods used for precise molecular structure determination, as well as their use in combination and the significance of accurate structural data in modern chemical research (in the preface). The 22 chapters have been written by
recognized experts. A bibliography is given at the end of each
chapter, and the book concludes with author, subject. and
formula indexes (although the last is very incomplete). The
editors have set out to cover the whole of the field. but it is
not possible for a single book to fulfill this ambitious aim.
Nevertheless, it is a mine of information that will be of considerable interest to every structural chemist who wants to
look beyond the immediate confines of his or her particular
method.
The first chapter gives an excellent general introduction to
the subject. After a short account of the historical background, experimental and theoretical methods used for
structure determination are briefly sketched. and the importance of obtaining precise structural data is illustrated by a
few well chosen examples.
Chapter 2 is concerned with the derivation and significance of potential functions for di- and polyatomic molecules; here the reader is assumed to have extensive mathematical knowledge in the area of group theory. Included here
is a survey of the different ways of defining interatomic distances which is especially important. The chapter ends with
a table listing experimentally measured data on equilibrium
structures and anharmonic potential constants for polyatomic molecules; unfortunately, though, the literature references given here extend only to 1988, which does not entirely fulfill the book’s declared aim of presenting “current
chemical research”.
Chapter 3 deals with microwave spectroscopy. The fundamental principles are derived and discussed, and their application is illustrated by describing a structure determination
carried out using this method.
Chapter 4 is devoted to structure determination by vibrational-rotational spectroscopy. The author confines his discussion mainly to IR spectroscopy, and describes the mathematical formalism and procedures for di- and polyatomic
molecules.
The treatment of gas phase electron diffraction (Chapter 5) begins with the development of the method, followed
by the theoretical fundamentals and the experimental details. An example of a structural analysis is then described,
together with a discussion of the uncertainties in the information yielded by the method. Chapter6 gives an easily
understandable introduction to the basic principles of single
crystal structure analysis by X-ray diffraction. Subject matter which normally fills thick textbooks is here compressed
into about 30 pages. One is prompted to wonder for whom
this chapter has been written. The reader already familiar
with these matters can either miss it out or use it as a source
of ideas on how best to teach the subject. For the novice,
however, it is so elementary that it requires too great a jump
to Chapters 7-1 1 that follow. Even the ten-page glossary at
the end of the chapter, a feature that is unfortunately missing
from most textbooks, is not enough to put this right. For any
structure determination by X-ray diffraction that is more
than just a routine measurement, to obtain precise data one
must not only have a suitable crystal, but must also make
measurements at as many angles as possible, repeated as
Документ
Категория
Без категории
Просмотров
0
Размер файла
307 Кб
Теги
chemistry, book, gate, catalytic, review
1/--страниц
Пожаловаться на содержимое документа