Studies in sesquiterpenes—LVII: isolongifolene (part 8): solvolysis of 8-bromoneoisolongifolene

Acetolysis of 8-bromoneoisolongifolene generates, besides two normal products (of elimination and SN2 displacement), which were minor, one rearranged elimination product and a tertiary acetate. The rearranged diolefine arises from acetic acid-catalysed rearrangement of the normal elimination product, while the tertiary acetate is a Wagner substitution product arising from a syn-migration. In this context various factors controlling such migrations are discussed and, the possible role of energetics of the incipient carbonium ion at the migration origin highlighted