R. Shepherd
Jul 15, 1993
Citations
0
Influential Citations
35
Citations
Journal
Inorganica Chimica Acta
Abstract
Abstract The cis -stilbene oxide/ trans -stilbene oxide isomer assignment given formerly in Inorg. Chim. Acta, 193 (1992) 217 should be reversed. This assignment was based on the 1 H NMR spectra of the stilbene oxides given in The Varian High Resolution NMR Spectral Catalog , Vol. 2, which is in error. The large amount of trans -oxide versus cis -oxide (5.5:1) from the cis -stilbene epoxidation by [Ru III (hedta)]/t-BuOOH, and 100% trans -oxide from trans - stilbene, is reinterpreted as indicative of a radicaloid intermediate in ⩾85% of the reaction channels. Comparisons are made with 15 ruthenium oxo catalysts which epoxidize stilbenes. Two categories are observed which are (A) stereoretentive Ru IV O catalysts or sterically hindered Ru VI O porphyrin oxidants, and (B) those which give isomer mixtures for Z -olefins and which are less hindered Ru V O and Ru IV O catalysts. The mechanistics aspects of these epoxidations are discussed.