Gas-phase reactions on platinum. Synthesis and crystal structure of anti- tetramantane, a large diamondoid fragment

anti-Tetramantane, a C22H28 hydrocarbon having the regular topology of the diamondoid lattice, has been synthesised by a double homologation of diamantane, the key step involving a ring expansion–cyclisation reaction of a polycyclic diene in hydrogen in the gas phase on a platinum-silica catalyst; the structure has been established by an X-ray crystal analysis.