Silver(I) Ion-catalyzed Rearrangement of 3,5-Dehydronoriceane (Pentracyclo2,6.03,5.04,9>undecane). Empirical Force-field Calculations and Behavior of 3-Noricyl(Tetra2,6.04,9>undec-3-yl) Cation

Article abstract of DOI:10.1246/bcsj.53.3313

Treatment of 3,5-dehydronoriceane (1) with a catalytic amount of silver tetrafluoroborate results in a novel skeletal rearrangement to afford tetracyclo<5.3.1.0^2,6.0^3,9>undec-4-ene(2,4-ethenonoradamantane)(5) in 85 percent yield.Empirical force-field calculations suggest that there is no substantial difference in strain energies between 1 and bicyclo<2.1.0>pentane which is inert toward silver(I) ion.Acetolysis of endo-3-noricyl(endo-tetracyclo<5.3.1.0^2,6.0^4,9>undec-3-yl) tosylate (7) gives exo-3-acetoxynoriceane(exo-3-acetoxytetracyclo<5.3.1.0^2,6.0^4,9)undecane (11), exo- 4-acetoxytetracyclo<5.3.1.0^2,6.0^3,9>undecane (12), and 5 in a ratio of 36 :42 :22.Similar acetolysis of exo-isomer of 7 gives the same products but in different ratio (11:12:5=9:47:44).A stepwise carbocation mechanism is proposed for the above mentioned silver(I) ion-catalyzed rearrangement.