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Beyond the Molecular Frontier Challenges for Chemistry and Chemical Engineering. Edited by the Committee on Challenges for the Chemical Sciences in the 21st Century. Board on Chemical Sciences and Technologies

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3-ols (e.g., catechin), with attention to
protection and deprotection tactics for
preparing specific regioisomers. Access
to these various conjugates is important,
for they are the flavonoid metabolites
that exert biological activity in vivo.
Typical experimental procedures are
The last six chapters cover all there
is to know about identification, purification, and structural characterization
of selected polyphenols. Some of the
information is already contained in
previous sections of the book, but
these chapters are each dedicated to
one particular class of polyphenols.
Chapter 11, by Bond and co-workers,
will be especially useful to those interested in tea chemistry. Isolation protocols, major sources, key chromatographic steps, and physical properties,
together with detailed NMR data on tea
catechins, their gallate esters, and blacktea oxidation products (theaflavins and
thearubigins), are provided in this
“handchapter” of tea polyphenol
chemistry, well complemented with a
myriad of useful practical tips. The
following two chapters, by Lazarus and
her colleagues and by Cheynier and
Fulcrand, focus on proanthocyanidin
oligomers and polymers. The various
methods available for determining the
degree of polymerization by using NMR
spectroscopy, mass spectrometry, gel
permeation, or acid-mediated depolymerization, including the classical Bate–
Smith reaction, thiolysis, and phloroglucinolysis, are reviewed and compared.
NMR spectroscopy and mass spectrometry are used to gather detailed structural information, such as the nature and
proportion of the flavan-3-ol constitutive units, the type of interflavanoid
linkages, and the extent of galloylation.
In Chapter 14, Michael Clifford presents
the analysis of the only class of nonflavonoid polyphenols discussed in this
book, the cinnamoyl esters, exemplified
by the chlorogenic acids found in large
quantities (up to 100 g/Kg) in green
coffee beans. Analysis of anthocyanin
pigments is the topic of Chapter 15 by
Rivas-Gonzalo. In the closing chapter,
Tom6s-Barber6n and his colleagues discuss the analysis of flavanones such as
hesperidin and naringenin, their chemically interconverting open-form chalcones, and dehydrochalcones, which
are minor flavonoids found in significant
quantities in citrus fruits, tomatoes, and
apples; all these are important dietary
contributors present in many fruitderived products.
In summary, this volume constitutes
an excellent addition to the literature on
polyphenol chemistry. Up-to-date references are given in each chapter, and the
index is adequately organized to quickly
search for a particular topic. The fact
that other bioactive plant polyphenols
have been left out could be criticized in
view of the general title of the book, but
the focus on flavonoids is understandable, given the important contribution
of this class of polyphenols to the human
diet. The numerous experimental
descriptions provided, in concert with
discussions on detailed practical tips,
make this book a must-read for natural
products chemists, food scientists, and
pharmacologists with interests in the
chemistry of flavonoid polyphenols and
their role in nutrition–health relationships.
Stphane Quideau
Institut Europen de Chimie et Biologie
and Laboratoire de Chimie des
Substances Vgtales
Universit Bordeaux I, Talence (France)
Beyond the Molecular Frontier
Challenges for Chemistry and
Chemical Engineering
Edited by the Committee on Challenges
for the Chemical
Sciences in the 21st
Century. Board on
Chemical Sciences
and Technologies.
National Academies Press, Washington, D.C. 2003.
224 pp., hardcover
$ 34.95.—ISBN
For almost 50 years, work-groups of the
United States National Research Coun-
5 2004 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
cil have produced reports on the current
situation in the chemical sciences,
addressing questions such as: Where
do the chemical sciences stand today?
How have they arrived at the present
stage of development? In which directions will they, and/or should they, continue to develop? The Westheimer
Report of 1965 (“Chemistry—Opportunities and Needs”), the Pimentel Report
of 1985 (“Opportunities in Chemistry”),
and the Anderson Report of 1988
(“Frontiers in Chemical Engineering”)
attempted to answer these questions.
The latest such report, setting out
the conclusions of the above-named
committee under the editorial leadership of Ronald Breslow and Matthew V.
Tirrell, differs from the previous volumes in that it attempts to cover the
entire spectrum of the chemical sciences, from fundamental research at the
molecular level to industrial-scale process technology. The interdisciplinary
character of chemistry is emphasized
throughout, in areas such as its interactions with other natural sciences, and
with agriculture, medicine, the environmental sciences, the information sciences, and many other technologies. The
central core of this new report consists
of 11 chapters that all follow the same
pattern. Each one begins by listing
important preconditions for the future
of the field concerned. That is followed
by a description of the aims of the field,
then an account of the results and
successes achieved up to now. Lastly,
the chapter explains why this particular
field and the developments within it are
considered to be important.
Some of the key areas that the
editorial committee, taking the advice
of many experts, have chosen for reporting and discussion are: synthesis and
production (Chapter 3), which is the
central activity of chemistry, chemical
and physical transformations of matter
(Chapter 4), and the broad field of
analysis (Chapter 5), including new
developments in methods for isolating
constituents, new methods of identification and imaging, and the elucidation of
the molecular structures of chemical
compounds. Chapter 6 is devoted to
computational methods and theory,
with special emphasis on the growing
importance of these two areas for chemical production and engineering. ChapAngew. Chem. Int. Ed. 2004, 43, 393 – 396
ter 7 and those that follow are concerned with the huge importance of
chemistry in many interdisciplinary
areas of research. Chemistry at the
borders of biology and medicine is
followed in Chapter 8 by a detailed
discussion of its interaction with the
materials sciences, then in Chapter 9 by
atmospheric and environmental chemistry. Chapter 10 is devoted to the chemical aspects of energy production, which
has political and other implications.
Chapter 11 discusses the important role
of chemistry in finding solutions to
problems of national and personal
security, whether in the detection of
dangerous substances or the early recognition of terrorist threats—certainly
an area of extreme interest today, and
one that did not even need to be
considered in the earlier reports. In the
final chapter the authors conclude that
the chemistry of the future will emphasize multidisciplinary initiatives, and
that the teamwork culture that is
urgently needed should be recognized
and practiced in the education and
training of chemists. Greater attention
should also be given to individuals'
suitability for teamwork, for example
when recruiting staff. Chemists and
chemical engineers should in future
take greater care in communicating
with the media than at present. Furthermore, to enable the chemistry of the
future to attain its far-reaching aims,
there is an urgent need for women and
minority groups to play a greater role
than they now do.
The report ends with a list of “Grand
Challenges”, which is, however, not
intended to cover all the directions of
research that should be pursued. One
important objective listed by the authors
is to have the ability, for any new
substance that shows promise of scientific or practical importance, to produce
it by a short synthetic route and an
economical process, with high selectivity
and low energy consumption, without
generating environmentally harmful byproducts or residues. As every chemist
knows, that is at present a very distant
goal, despite all the successes that have
been achieved. For most of the substances generated by academic research
(which form the majority of new compounds), the overall yields in relation to
crude oil as the starting material
Angew. Chem. Int. Ed. 2004, 43, 393 – 396
scarcely even reach fractions of one
part per thousand. Another objective is
to be able to control and modify the
reactivities of molecules over all conceivable timescales and sizes. That
implies the ability to manipulate single
molecules and to observe molecular
structures directly during chemical reactions, using ultra-fast electronic or optical pulses combined with X-ray diffraction—in other words a complete structure determination, even for transition
states. Yet another aim is to be able in
future to predict the properties of new
compounds, materials, and molecular
machines, and to tailor and fine-tune
these before starting to synthesize and/
or produce them. The scenario ends with
the aim of recruiting the best and
cleverest young people as chemistry
Of course, the editorial committee
are well aware of the limitations of any
such list of proposals, and they know
that the historical development of
chemistry has shown again and again
that the spirit blows in whatever direction it chooses. Nevertheless, it is appropriate to occasionally review the state of
progress, to stand aside from the everyday hurly-burly to pause for breath and
take stock. Not the least of the benefits
of reports of this kind is that they are
also very clearly addressed to an audience beyond chemistry: to politicians
and other decision-makers, and to interested members of the general public
who just want to know what modern
chemical research is about. To that
extent we, as practitioners of chemistry,
should be grateful that the editors and
authors have made the effort to put
together this detailed study, and have,
moreover, presented their results in
clear and easily understandable language. I am sure that, like its predecessors, this report will be frequently and
enthusiastically cited in discussions
about the future development of
Henning Hopf
Institut f<r Organische Chemie
Technische Universit>t Braunschweig
DOI: 10.1002/anie.200385074
Handbook of Metathesis
Vol. 1–3. Edited by
Robert H. Grubbs.
Wiley-VCH, Weinheim 2003.
1156 pp., hardcover
E 479.00.—ISBN
Although alkene and alkyne metathesis
had been known for many years, it was
the discovery of highly efficient, functional-group-tolerant catalysts in the last
decade that converted metathesis into a
generally applicable synthetic tool. This
exciting development culminated in the
synthesis of various structurally complex
natural products with metathesis as the
key carbon–carbon bond-forming step.
The multi-author three-volume set
“Handbook of Metathesis” covers most
aspects of the discovery, development,
and applications of alkylidene-complexbased catalysts for alkene and alkyne
metathesis. Volume 1, Catalyst Development, focuses on the historical aspects
of the development of these catalysts
and on their mechanism of action. The
first eight chapters of this volume
describe in detail how alkylidene complexes were found to be the key intermediates in alkene metathesis, and how
the evaluation of various types of alkylidene complexes ultimately led to the
currently mostly used molybdenum and
ruthenium carbene complexes. The
mechanism of alkene metathesis by
ruthenium carbene complexes is treated
in depth in Chapters 9 and 10, while the
remaining two chapters of Volume 1
discuss the discovery and development
of alkylidyne complexes for alkyne
metathesis and the preparation and
properties of silica- and alumina-supported metathesis catalysts.
Particularly appealing in this volume
are the thrilling personal accounts by
Schrock, Katz, Nguyen, and others
about how the catalysts were continuously improved and the structural
requirements for a good metathesis
catalyst slowly emerged. Unfortunately,
the only type of metathesis catalysts
covered in this volume (and in the
5 2004 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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