book reviews The plans call for the series to be presented in about fifty volumes. The following are now available: Beryllium; Zirconium and Hafnium; Thallium; Ruthenium; Cobalt; Thorium; Molybdenum; Plutonium; Boron; Nickel; Potassium; Uranium; Technetium; Promethium, Asatine, and Francium; Yttrium and the Lathanide Elements; Niobium and Tantalum; Protactinum; Gallium. WFK
Orbital Symmetry, A Problem Solving Approach Roland E. Lehr and Alan P. Marehand, both of The University of Oklahoma. Academic Press, New York, 1972. x + 190 pp. Figs. and tables. 23 X 15 cm. $4.95.
This is an interesting paperback on the subject of allawedness and forbiddenness in organic reactions. It differs from the Woodward and Hoffmann reprint of their Angewandte Chernie article in including some different approaches and secondly in giving examples as problems supplemented with answers. The hook is more closely related to the recently published French counterpart "Les Regles de Woodward Hoffmann"
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1 Journal of Chemical Education
published in French by Ediscience under the authorship of Nguyen Trong Anh; it is the reviewer's understanding that an English version is in preparation. The present book by Lehr and Marchand covers much of the Woodward Hoffmann approach with the usual sets of rules. This much probably does not offer advantage over the Woodward Hoffmann monograph. Similarly, the section an correlation diagrams assumes knowledge of MO theorv in writine the molecular orbihave merit in pedagogy. However, the problems along with bountiful literature citations and solutions will prove interestingand challenging to students. What might have been the strength of the book, namely the small remainder of the book dealing with the Frontier Orbital method of Fukui, the Mobius-Huckel method of Zimmerman, and the Perturbational Approach of Dewar, turns out to be interesting but does not quite do the job. The early and extensive contributions of Fukui are not emphasized. In the case of the Perturbational Approach of Dewar, only a little space is given and this is not enough to get the reader used to using the method. Then the authors somehow confuse and intertwine this method with the Mdbius-Hiickel method of Zimmerman despite Dewar's clear preference far a perturbation approach. What may be eanfusing to students reading the references cited is that although the Mobius concept is equated with Dewar's approach, Dewar in the literature cited does not interpret the
term "Miibius" as relating to the odd number of sign inversions as stated in the text but rather to topology. Also, this section (and the book) could have been stronger if only in place of the innumerable separate rules, the authors had used the simple rule by Zimmerman that the Hiickel systems have zero or an even number of phase discontinuities between A O t and the Mobius systems have an odd number. This is cited on one page but not used. Curiously, it is attributed to Dewar whose literature usage and note of this will be limited in the references cited. Thus, while the simple rule is there, only the clever student will realize that it actually covers all the sub-rules given. There are a few minor errors. One of the most serious is a misdrawing of the overlap in a 1,3-sigmatropic rearrangement on page 21. A reviewer perhaps tends to look a t weak points rather than strong ones. Potential readers deserve report of both aspects. Presently, on the positive side, this book can be of value to students who have gotten through the Woodward and Ha#mann monograph and want more. Also, it can be used to get the student practiced in handling such problems. There are many interesting literature references, too; and this is an advantage. The book can be recommended in any case, and especially if used under the guidance of a lecturer who can clarify various aspects. Howard E. Zimmerman University of Wisconsin Madison. Wisconsin 53706
lcontinued rm p a p A 112)
