Dimerization of pentacyclopentacorannulene C 30 H 10 as a strategy to produce C 60 H 20 as a precursor for C 60 .

The chemical synthesis of C 60 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 (C 30 H 10 ) fragments employing the Diels-Alder cycloaddition reaction. Density functional calculations indicate that a step wise non-concerted dimerization mechanism of C 30 H 10 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 C 60 H 20 . The results then suggest the synthesis of C 60 H 20 as a precursor for C 60 . The synthesis of the analogue C 60 F 20 has already been reported.