REARRANGEMENTS OF 6-BICYCLO[3.2.1]OCTYL CATIONS

Rearrangements of 6‐Bicyclo[3.2.l]octyl Cations 6‐Bicyclo[3.2.1]octyl cations were generated by nitrous acid deaminations of the amines 12, 14 and by acetolyses of the tosylates 9, 20. the major products are bicyclo[3.2.1]octan‐exo‐6‐ol (17), bicyclo[3.2.1]octan‐exo‐2‐o. (18), and bicyclo[2.2.2]octan‐2‐ol (19). 4,6(4,5) hydride shifts account for the formation of 18 and 19. The product distributions indicate substantial kS contributions for he endo precursors while the exo precursors react almost exclusively by way of carbocations, as confirmed by the ring expansion of bicyclo[4.1.1]octane‐2‐di‐azonium ions (30. The product distributions obtained from the exo‐diazonium ion 15n and from the exo‐tosylate 20 are rather similar, but hte distributions of a deuterium label differ strongly. Dediazoniation of 15 leads to a highly unsymmetrical intermediate, whereas acetolysis of 20 involves an effectively equilibrated species. These findings cannot e interpreted in terns of open ions. Unsymmetrically bridged ions, whose conformational equilibration competes with substitution and hydride shifts, provide a consistent explanation. Copyright © 1990 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim