oxygen), mainly in synthetic organic chemistry. In addition a few articles are devoted to unusual types of bonding in compounds of main-group elements. The choice of eminent authors has ensured that the book is successful in meeting these aims.
K Apeloig deals with bonding and structure in some unusual silicon compounds. This article is a good summary of the same author's contribution to "The Chemistry of Organic Silicon Compounds" (edited by S. Putui and Z . Ruppoport), which appeared in 1989. A . J Arduengo IZI and D . A . Dixon present experimental and theoretical evidence show- ing that trivalently bonded compounds of the "pnictogen" elements can undergo not only the familiar textbook vertex inversion process (tetrahedron-trigonal-planar intermediate-tetrahedron), but also an "edge inversion process" (tetrahedron-square-planar intermediate-tetrahedron). This new process is illustrated by the example of Arduengo's Tshaped compounds of main-group elements. In discussing the problem of color in pentaarylbismuth compounds K. Seppeft draws attention to the unusual bismuth-carbon bonding in these hypervalent species; relativistic effects must be invoked to account for the phenomena that are observed. This group of contributions dealing mainly with theoretical and physical chemical aspects ends with an article by J B. Lurnhert, G. Wung and E. C . Chelius in which they discuss the j3-effect of trimethylsilyl, -germyl and -stannyl groups in the solvolysis of cyclohexyl and cyclopentyl derivatives.
Four articles are devoted to the reactivity and synthetic applications of sulfoxides. Those by H . B . Kugun and A . Ohno are concerned with chiral sulfoxides, whereas 0. De Lucchi et al. discuss atropisomeric binaphthylsulfones and -sulfoxides as chiral auxiliaries. N . Furukuwu describes an investigation into the question of whether sulfuranes are formed as intermediates in the reaction of sulfoxides with organometallic reagents, and considers the possible synthetic applications of these experiments.
A further contribution on the chemistry of hypervalent heteroatoms is provided by D. H. R. Burton, who describes ligand coupling reactions applied to pentacoordinated bismuth compounds. r -Z . Huung et al. give an impressive account of the use of arsene ylides in synthesizing polyenes and sensitive natural products. Some insights into the chemistry of organoselenium compounds are provided by K Ando and N . Tokitoh, who describe the photolysis and pyrolysis of selenium-and sulfur-containing heterocycles to form highly reactive intermediates. The section on polyselenium and polysulfur heterocycles is especially interesting, and includes some hitherto unpublished results. is G. Buck et al. report on the selenosulfonation of alkenes and alkynes and some applications of this method in steroid chemistry. A . Krief et al. have succeeded in synthesizing molecules in which quaternary carbon atoms are linked together, by proceeding via a-lithioselenides.
Two articles deal with the chemistry of low-valency compounds of main-group elements. In the first of these M . Regitz discusses the synthesis of phosphaalkynes and the chemistry based on these. Although detailed and up-to-date reviews of this topic already exist,[*] the fascinating possibilities opened up by this chemistry simply had to be included in this book. The second article is an updated survey of the chemistry of siloxy-substituted silenes, an area which is the specialty of A . G . Brook. 7: Cohen describes the use of phenylthioethers to synthesize carbanions which would otherwise be accessible only with great difficulty or not at all.