Reinvestigation of the Bicyclooctane-1,4-diyl Dication

Article abstract of DOI:10.1021/jo00225a051

The reaction of 1,4-dihalobicyclo<2.2.2>octanes 2-Cl and -F with SbF5/SO2ClF was reinvestigated and found by 13C NMR spectroscopy and quenching experiments to yield only the 4-halo-1-bicyclo<2.2.2>octyl monocation mono-donor-acceptor complexes 3-X-SbF5 under any of the tested conditions.In SO2-containing solutions disulfoxonium ion 7 formed, indicating that if dication 1 were intermediately formed it alkylates SO2. 7 may, however, also be formed by stepwise alkylation.The previously reported stable 1,4-bicyclo<2.2.2>octanediyl dication 1 could not be detected.The results are consistent with the observation that the structurally similar 1,5-trishomobarrelenediyl dication 4, which is expected to be more stable than 1, could not be observed.