Regioselective amination of carbaporpholactone and N-confused porphyrin.

An efficient route to the direct amination at the inner carbon of carbaporpholactone is reported. A regioselectivity of substitution is enforced by activation of the embedded furanone fragment due to coordination of the highly oxidized silver(III) cation. A stepwise oxidation of the dimethylamine derivative leads to the internally bridged carbaporpholactones which contain respectively [5.7.5] tricyclic or [5.7.5.7.5] pentacyclic rings. The analogous reactivity of N-confused porphyrin has been also explored.