Displacement Stereochemistry and Product-Formation Selectivities in the Solvolysis of Cyclooctyl p-Bromobenzenesulfonate

Article abstract of DOI:10.1021/ja00365a036

Configurational analysis by 2H NMR of the products of solvolysis of (E)-cyclooctyl-2-d and (E)-cyclooctyl-4-d brosylate in acetic acid and 80percent acetone has established that substitution without rearrangement occurs with complete retention of configuration while substitution under 1,5-hydride shift takes place with complete inversion at the migration origin.The reaction is concluded to proceed by direct initial formation of a 1,5-hydrogen-bridged cation.Solvolysis of cyclooctyl-1-d brosylate in several solvents has shown elimination to be favored from C-1 over the C-5 side, whereas selectivities for competitive substitutions are similar at the two positions.Elimination is thus indicated to take place largely from first-formed tight ion pairs while displacement proceeds through more dissociated intermediates.