Dimerization of pentacyclopentacorannulene C₃₀H₁₀ as a strategy to produce C₆₀H₂₀ as a precursor for C₆₀

The chemical synthesis of C₆₀ fullerene in the laboratory is still a challenge. In order to achieve this goal, we propose a synthetic route based on the dimerization between two pentacyclopentacorannulene (C₃₀H₁₀) fragments employing the Diels-Alder cycloaddition reaction. Density functional calculations indicate that a step wise non-concerted dimerization mechanism of C₃₀H₁₀ is favored over a one stage dimerization. The step wise dimerization implies the sequential formation of 2, 4, 6, and 10 new C-C bonds between the two fragments. This leads to the formation of the Diels-Alder cycloadduct C₆₀H₂₀. The results then suggest the synthesis of C₆₀H₂₀ as a precursor for C₆₀. The synthesis of the analogue C₆₀F₂₀ has already been reported.