Benziporphyrin, a Benzene‐Containing, Nonaromatic Porphyrin Analogue

Abstract

Benzene wins the battle for aromaticity against [18]annulene. The first fully conjugated, benzene-containing porphyrin analogue 1 is not an 18 π aromatic system; only the tautomer with the intact arene is observed. This compound is synthesized from the corresponding tripyrranedicarboxylic acid and isophthalaldehyde and forms black-blue crystals.