Biomimetic hydroxylation of aromatic compounds: Hydrogen peroxide and manganese-polyhalogenated porphyrins as a particularly good system.

Abstract

Various iron- and manganese-porphyrins were compared as catalysts for the hydroxylation of anisole by H2O2 or PhIO. Whereas all the iron-porphyrins tested gave low hydroxylation yields, Mn(III)-meso tetraarylporphyrins bearing halogen substituents on their meso-aryl and pyrrole groups gave good yields (up to 70% based on the oxidant) for the para-hydroxylation of anisole, especially with H2O2 as oxidant in the presence of imidazole. Under these conditions, phenanthrene was quantitatively oxidized into its 9,10-epoxide and naphthalene was mainly oxidized into 1-naphthol (40% yield). Hydroxylation yields appeared dependent upon the reactivity of the oxidizing system not only toward the starting aromatic compound but also toward the phenol products. © 1990.