Intramolecular aromatic hydroxylation via irradiation of pyridine N-oxide derivatives

Abstract

The photochemical behaviour of 2-benzyl-, 2-phenethyl-, and 2-phenoxy-pyridine N-oxides is reported. In the presence of boron trifluoride rearrangement reactions, involving migration of oxygen around the pyridine ring, are inhibited, resulting in an increase of hydroxylation of the attached phenyl system. The mechanism of the aromatic hydroxylation reaction is shown to involve transient formation of benzene oxides.