Direct amination of the antiaromatic NiII norcorrole

Abstract

We have discovered a facile amination reaction of Ni^II dimesitylnorcorrole, which is an antiaromatic porphyrinoid with a 16π-electron conjugation system. The amination reaction proceeded at the β-positions of the norcorrole with high regioselectivity upon treatment with various amines used as solvents. The reaction requires neither catalysts nor pre-functionalization of the norcorrole. The optical and electrochemical properties of the amino norcorroles were substantially modulated by electron-donating nitrogen atoms. According to theoretical studies, the regioselectivity of amination can be accounted for by molecular orbitals of the norcorrole.