Bis-corannulenoanthracene: An Angularly Fused Pentacene as a Precursor for Barrelene-Tethered Receptors for Fullerenes

Bis-corannulenoanthracene (C50H22, 5) was prepared by the Diels-Alder double cycloaddition of isocorannulenofuran with "bis-benzyne", followed by deoxygenation of the adducts. Despite the presence of a pentacene core, 5 is stable enough to be isolated and stored. A cycloaddition reaction of 5 with maleic anhydride produces 10 which exhibits strong affinity toward C60, as evidenced by (1)H NMR titration experiment. Synthesis of 10 demonstrates the synthetic utility of hydrocarbon 5 in the preparation of the barrelene-based molecular clips with two benzocorannulene pincers adorned with polar substituents on their tethers, which will allow for immobilization of the receptors on solid supports.