Synthesis of a shape-persistent macrocycle with intraannular carboxylic acid groups

The synthesis of a shape-persistent macrocycle based on the phenylene–ethynylene backbone by the intermolecular oxidative Glaser-coupling of appropriate bisacetylenes is described. The ring contains two intraannular methyl carboxylates that were hydrolyzed to give the free diacid. In order to achieve sufficient solubility it was necessary to attach additional intraannular branched alkyl groups to the ring.