Synthesis of Polycyclic Hydrocarbons C14H20 by Hydrogenation of exo–exo-, exo–endo-, endo–exo-, and endo–endo-Hexacyclo[9.2.1.02,10.03,8.04,6.05,9]tetradec-12-enes with H2SO4 and Isomerization of the Products to Diamantane Induced by Ionic Liquids

A new method has been developed for the complete (full) hydrogenation of unsaturated hexacyclic norbornadiene dimers, namely, exo–exo-, exo–endo-, endo–exo-, endo–endo-hexacyclo­[9.2.1.02,10.03,8.04,6.05,9]­tetradec-12-enes at the double bond and the cyclopropane ring using sulfuric acid (98%) to form pentacyclo­[8.2.1.15.8.02.9.03.7]­tetradecanes in 51–76% yield. Hydrogenolysis of exo–endo- and endo–endo-tetradecenes containing the most shielded cyclopropane cycle occurs with the skeletal rearrangement. Sulfuric acid is the hydrogen donor, cyclohexane is the solvent, and the hydrocarbons themselves are transformed into benzene and aromatic products of an unknown structure. It was found that under the action of the [Et3NH]+[Al2Cl7]−-CuCl2 ionic liquid, pentacyclo­[8.2.1.15,8.02,9.03,7]­tetradecanes are selectively isomerized to diamantane in 80–84% yield.