Synthesis of Triamantane

Article abstract of DOI:10.1021/jo01312a026

Triamantane, 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 + 4> dimer, binor S (5), either in solution using silver perchlorate or in gas phase on silica gel, gives two hexacyclic olefins (13 and 14) suitable (without separation) for further elaboration: <4 + 2> cycloaddition with butadiene gives C18 adducts whose hydrogenated forms (26 and 27) are converted by aluminum chloride catalyzed rearrangement into triamantane in 60percent yield.Byuse of isoprene instead of butadiene in the cycloaddition stage the synthesis can be modified to produce 9-methyltriamantane.The mechanism of the binor S rearrangement is discussed.