COMPETING METHOXYMERCURATION AND RING-MERCURATION REACTIONS OF SOME ALKYLVINYL-SUBSTITUTED FERROCENES

Product analysis and kinetic data for the reaction of some alkylvinylferrocenes with mercuric acetate in methanol are reported. Depending on the location and nature of the alkyl group(s), exclusive addition or ring-substitution reactions are observed as well as both reactions together. This behaviour is interpreted in terms of the relative polar and steric effects. Styrene has also been investigated under similar conditions to provide comparisons of mechanistic significance. The methoxymercuration reaction seems to proceed via a slowly formed, possibly bridged intermediate, with weak carbonium ion character; with the ferrocene derivatives as substrates it appears to be a complex process as suggested by an anomalous temperature-dependence behavior. © 1979.