| Abstract
| - Friedel−Crafts acylation of nickel meso-tetraarylporphyrins with aryl anhydrides, followed by air oxidationin the presence of pyridine, DMAP, and excess anhydride, produced corroles in 8−21% yields. Otherproducts include a porphyrinic ketone, an additional corrole whose bridge has been retained as an acylgroup attached to a pyrrole, and a lactone resulting from the insertion of an oxygen atom into an α,β-pyrrole bond. The ring contraction is best explained by a pinacolic rearrangement reminiscent of the onetaking place in the formation of corrinoids, a benzoyloxy group replacing the acetic side chain found inthe natural products.
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