Chemical Education Today
Book & Media Reviews
Organic Reactions in Aqueous Media by Chao-Jun Li and Tak-Hang Chan Wiley: New York, 1997. xi + 199 pp. Figs. and tables. 16.0 × 23.5 cm. ISBN 0-471-16395-3. $ 59.95. reviewed by Alan Rosan
This concise book joins the series of Wiley Interscience special topic publications. In seven chapters it selectively reviews the burgeoning literature on organic reactions conducted in water or in aqueous media as a reaction cosolvent, nicely complementing another recent book on the subject by Grieco. Following a short introduction there are six chapters that vary in length from 10 to 50 pages; they cover pericyclic reactions, nucleophilic additions and substitutions, metal-mediated reactions, transition metal–catalyzed reactions, oxidation and reduction reactions, and industrial applications. These chapters, each of which is prefaced with a short provocative quotation, also vary in depth, containing from 11 to more than 180 references. The literature is complete through 1996 and commendably includes citations of original papers by Barbier, Faraday, Frankland, Grignard, Kolbe, Lapworth, and Reformatsky as well as references to selected U.S. and foreign patents and the Russian literature. There is a subject index but no author index. This book is timely and effective. From the title, one might expect a broad discussion of the unique properties of water and water-soluble components (salts, surfactants, etc.) that would be thought to bear on organic reactivity. The first chapter opens by noting that water is the most abundant volatile material in comets and briefly describes those properties that suggest its utility as a solvent or cosolvent, summarizing the potential technical, economic, and environmental advantages. Also described are the remarkable changes in density, conductance, heat capacity, dielectric constant, and ionization constant that accompany the transition to the critical point, but the emphasis here is on the effect of water under noncritical conditions. Discussion of the structure of liquid water and the role of hydrogen bonding in mediating molecular recognition events is abbreviated. In fact, the term “hydrogen bond” is surprisingly absent from the index. The text does not explicitly include a discussion of what has come to be broadly termed biphasic reaction conditions. Understandably, enzymatic reactions are beyond the scope of the presentation. This book has a decidedly applied character with an understated environmental theme, and the authors succinctly present the extraordinary effects of water on the kinetics, efficiency, and stereoselectivity of a large number of diverse reactions. In addition to their emphasis on the historically significant aqueous Diels–Alder reaction, discovered in 1980, and the literature regarding reactions of various nucleophilic organometals, the authors are to be commended for
edited by
Jeffrey Kovac University of Tennessee Knoxville, TN 37996-1600
gathering together a wide and diverse body of information: it is clear that many of the examples shown are gems buried among larger bodies of work. Thus the book does an excellent job of culling and surveying a vast amount of data. There is, however, less emphasis on organizing the mechanistic bases underlying these often dramatic effects. For example, the apparent lack of generality of the effect of water on rate and selectivity in pericyclic reactions calls for some theoretical foundation. The singularly effective use of aqueous TlOH in the Suzuki reaction is cited without comment. On the other hand, the authors’ concept of a mechanistic triad that incorporates to various degrees anion, radical, or covalent character in the carbon–carbon bond-forming step between various organometals and carbonyl substrates is appealing and suggests the need for future sophisticated experimental design. The most interesting sections are those dealing with synthesis and industrial applications. Unfortunately the latter is also the shortest chapter. The synthetic examples are timely and well chosen and include water-promoted Heck, Stille, Suzuki, and aldol reactions. There is an extensive, highly informative listing and survey of the use of water-soluble phosphines (both achiral and chiral) and an excellent discussion of the diastereoselectivity that often accompanies carbonyl attack by indium, tin, and zinc organometals (Barbier–Grignard reaction). The liberal use, on nearly every page, of clear, detailed drawings enhances the text, and substantive errors are few. Inexplicably, water is described as serving as a presumptive weak Lewis acid (pages 54–55) in the aqueous Mukaiyama reaction. Occasional slips of grammar, spelling, and syntax, including confusion over the difference between media and medium, are relatively minor. Some expressions, such as “olefinated”, are unfortunate and there are several mysterious changes in font. This is not a textbook and no problems are offered. Many technical advances, some occurring since this book was published, have impacted the economic and environmental advantages of water. However, these more recent findings, involving the use of triphase aqueous–fluorous–organic systems, the discovery of living homogeneous ROMP catalysis in water, the utilization of supercritical water oxidation for toxic cleanup, and the utility of biphasic supercritical carbon dioxide– water emulsions, can be appreciated within the broad scope of reactivity described here. With the emerging wide interest, technical feasibility, and rapid innovative advances and an increasingly vast literature in this area, this book is most useful as a selected compendium rather than a definitive treatise. It is certainly suitable as a reference in a special topics or an advanced course. Rich with well-explicated examples and reactions, it is an invitingly readable and valuable survey of this fascinating area. Alan M. Rosan is in the Department of Chemistry, Drew University, Madison, NJ 07940;
[email protected].
JChemEd.chem.wisc.edu • Vol. 77 No. 6 June 2000 • Journal of Chemical Education
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