Rearrangements of Internally-bridged Octaphyrin(1.1.1.1.1.1.1.1)s to Porphyrin Dimers

Abstract

Internally-bridged octaphyrin(1.1.1.1.1.1.1.1) underwent a rearrangement to meso-meso linked porphyrin dimer as a new metamorphosis. Extensive examination suggests that hydride-addition is a key step for the rearrangements to afford thermodynamically more stable porphyrin framework. Further, β-tetrabromo[36]octaphyrin was transformed to meso-meso, β-β, β-β triply linked porphyrin dimer via a similar mechanism combined with Pd-mediated reductive homocoupling.

Keywords: Expanded Porphyrin; Homoporphyrin; Rearrangement; Transannular Reaction.