Triamantanls, the third member of the diamondoid hydrocarbon series, has been synthesized efficiently in five easy stages from norbornadiene. Acid-catalyzed rearrangement of the norbornadiene [4+ 41 dimer, binor S (5), either in solution using silver perchlorate or in the gas phase on silica gel, gives two hexacyclic olefins (13 and 14) suitable (without separation) for further elaboration:[4+ 21 cycloaddition with butadiene ...