ortho-Specific alkylation of phenols via 1,3,2-benzodioxaborins

Abstract

Reaction of a phenol with an aldehyde in the presence of phenylboronic acid gives a 1,3,2-benzodioxaborin. The latter could be reduced to the corresponding ortho-alkylphenol with tert-butylamine borane in the presence of aluminum chloride. Alternatively, the dioxaborin, when reacted with an alkylthiol or an alcohol in the presence of an acid, gave the corresponding ortho-alkylthiomethyl- or ortho-alkoxymethylphenol. Keywords: phenol, alkylation, ortho-specific, 1,3,2-benzodioxaborin.