β-Trioxopyrrocorphins: pyrrocorphins of graded aromaticity.

ABSTRACT: Octaethyltrioxopyrrocorphins unexpectedly show macrocycle-aromatic properties, even though they contain the macrocyclic π-system of the non-aromatic pyrrocorphins (hexahydroporphyrins). Two of the four possible triketone regioisomers were first reported in 1969 by one-pot oxidation of octaethylporphyrin but remained essentially unexplored since. We detail here the targeted preparation of the remaining two triketone isomers and the optical and NMR spectroscopic properties of all isomers. All four regioisomers possess unique electronic properties, including broadly varying degrees of diatropicity that were experimentally determined using ¹H NMR spectroscopy and computationally verified. Structural patterns modulating the aromaticity were recognized. These differences highlight the

SUBMITTER: Chaudhri N 

PROVIDER: S-EPMC8480330 | biostudies-literature | 2021 Sep

REPOSITORIES: biostudies-literature