Stable carbonium ions. Part VI. Inter-cation exchange rearrangements of ferrocenylalkylium ions

Abstract

In CF₃CO₂H solution, α-substituted 1-ferrocenylethylium and 1-ferrocenyl-1-methylethylium cations rearrange to a mixture of the isomeric β- and 1′-substituted cations in the presence of ferrocene or an alkylferrocene, by means of an equilibrium controlled transfer of the (MeCH) or (Me₂C⁺) group between cations, ferrocene, or an alkyl derivative functioning as transport agent. Ruthenocenylalkylium ions, and thermodynamically more stable ferrocenylalkylium ions (e.g. FcCHPh, Fc₂CH) do not undergo similar rearrangements.