Oxidative Porphyrinoid Metamorphosis of Fourfold N-Confused [32]Octaphyrin Bis-Metal Complex to Doubly Linked...

We report an oxidative skeletal editing strategy that converts antiaromatic expanded porphyrins into structurally and electronically distinct porphyrinoids. Ni⁰-mediated cyclization of β,β'-dibromotetrapyrrin metal complexes furnishes fourfold N-confused (NC) [32]octaphyrin bis-metal complexes that exhibit global antiaromaticity. Subsequent site-selective oxidation at the inner α-positions triggers an unprecedented porphyrinoid metamorphosis, affording doubly linked 10-oxacorrole metal complex dimers via oxygen incorporation and skeletal reorganization. Notably, these products display dual electronic structures in which locally aromatic 18π 10-oxacorrole subunits are embedded within a globally antiaromatic 32π circuit, whereas diketo-octaphyrin metal complex products show globally aromatic 30π systems. This transformation demonstrates that oxidative functionalization of NC frameworks enables precise control over both molecular topology and π-electronic structure. These findings establish oxidative skeletal editing as a general strategy for inducing porphyrinoid metamorphosis and accessing previously unattainable aromaticity patterns.