One-pot Syntheses of Benzo- and Benzofuran-fused Iridaoxabenzenes via CH Bond Activations of Alkyl-bridged Diphenol Derivatives

Abstract

One-pot syntheses of new π-extended metallaaromatic compounds have been developed by utilizing Ir-mediated CH bond activation of ethylene- or ethylidene-bridged diphenol derivatives. Depending on the bridging alkyl groups, two types of iridaoxabenzenes, both of which are doubly fused with benzo and benzofuran units, have been obtained. Studies on their structures and electronic characters indicate that both complexes have an aromatic character on the iridaoxacycles, and their π-conjugated systems are fully delocalized over the whole molecular skeletons. These novel metallaaromatic complexes exhibited some reactivities which are distinct from those reported for the non-fused metallaaromatic compounds.

Keywords: CH activation; aromaticity; cyclometalation; iridaoxabenzene; metallaaromatic.