Extension of antiaromatic norcorrole by cycloaddition

Fu, X.; Meng, Y.; Li, X.; Stępień, M.; Chmielewski, P. J.
Chem. Commun. 2018, 54, 2510-2513 | view at publisher's site

The antiaromatic ring of norcorrole, a contracted tetrapyrrolic porphyrinoid, was subjected to [2+3] dipolar cycloaddition of iminonitriles. The paratropic character of the resulting chiral chlorines was retained. The chlorins were easily dehydrogenated in the presence of air, yielding pyrazole-fused norcorroles with markedly enhanced paratropicity.