A model for olefin hydration: intramolecular nucleophilic addition of phenolate oxygen to the unactivated double bond

Abstract

Two series of phenol–olefins with strained ground states cyclise rapidly to ethers at high pH, where the phenol is fully ionised. The reaction involves intramolecular nucleophilic addition of phenolate oxygen to a monoalkylethylene. A primary carbanion is not a full intermediate, but is well developed before proton transfer from a pre-associated water molecule or cationic general acid completes the reaction. The evidence suggests that the special conditions prevailing in enzyme active sites are likely to favour predominantly nucleophilic, rather than the usual electrophilic, attack on most olefins.