From Porphyrin Isomers to Octapyrrolic “Figure Eight” Macrocycles

Abstract

Cyclooctapyrroles such as 1–3 tend to form during the condensation of dipyrrolic units if cyclization to cyclotetrapyrroles is hindered for conformational reasons. These macrocycles are chiral and might afford interesting complexes with metal ions. Their most intriguing feature is their unusual figure-eight conformation.