Synthesis of diamantane by skeletal isomerization of pentacyclo[6.6.0.02,6.03,13.010,14]tetradecane induced by ionic liquids

Diamantane was synthesized by skeletal isomerization of a 2,6 3,13 10,14 new precursor pentacyclo[6.6.0.0^2,6.0^3,13.0^10,14]tetradecane being the hydrogenated norbornadiene dimer of an unusual structure wholly composed of five-membered rings. The isomerization was induced by ionic liquids based on aluminum, iron, nickel, manganese, zinc, tin, and copper salts, among which aluminate ionic liquids were the most efficient ensuring diamantane yields of up to 85%.