Nonaromatic corroles: regioselectivity of electrophilic substitution

Ring contraction of nickel meso-tetraarylporphyrins produced nonaromatic divalent corroles bearing a benzoyloxy function. We investigated their reactivity under electrophilic conditions: formylation, halogenation, nitration. We also found that the benzoate function could be eliminated to afford deoxocorroles, and we tested the formylation and nitration in this deoxo series. These corroles were generally very stable under the reaction conditions, and in both series, the directly bonded pyrroles were the most reactive. The nitration reaction produced a series of corrole dimers via electron transfer initiated coupling.