The Search for Long Range Aryl Migration in the Solvolysis of Suitably Positioned Monoaryl Derivatives in the Tricyclo2,4>octane and Bicyclooctane Skeletal Systems

Article abstract of DOI:10.1021/jo00190a018

Previous work has established that long range aryl migration (LRAM) and electrocyclic ring opening (ERO) combine (LRAMERO) to rearrange the exo-3,3-diaryltricyclo<3.2.1.0^2,4>oct-anti-8-yl system in solvolysis.Left uninvestigated in the earlier work were the necessity of the second ("stationary") aryl group and the extent and need that ERO contribute to the process.The present study involved the synthesis, characterization, and solvolytic behaviour of substrates designed to investigate these aspects of reaction.It has been determined that a second aryl group is not necessary in order to observe LRAMERO, although the proximate positioning of the migrating aryl group and the leaving group center remains critical.The syn-3-phenyl and syn-3-p-tolyl (note monoaryl) analogues of the previously studied diaryl systems exibit undiminished LRAMERO, whereas the anti-3-phenyl epimer is inert.The kinetics exhibited by the syn compounds, coupled with the rearranged products observed, additionally support the view that ERO occurs in concert with LRAM.Regretably, the question of the necessity of ERO remains unanswered.The bicyclo<3.2.1>octane substrate chosen to decide the question eschewed LRAM, presumably because of a conformational bias, and instead underwent solvolysis via ?-participation in exactly the same manner as its parent, the solvolysis of which was reported some time ago.