Novel pi-expanded radialene macrocycles with inner cavity

structure: see text] Polyenyne macrocycles with pi-extended 9]- and 12]radialene frameworks have been synthesized. These radialenes exhibit restricted rotation of the aromatic rings, and the D3- and D4-symmetric structures in solutions have been determined by dynamic NMR. The macrocyclic radialenes bear small to medium inner cavities, and the small cavity of the pi-extended 9]radialene can incorporate a silver cation.