Abstract Ring opening of the octane-β-sultones 1a-c by methanol gives the β- methoxyoctane-sulfonic acids 2a-c by SN 2 substitution at CO with inversion of the configuration. Hydrolysis of cis-and trans-4, 5-octanesultones 1a-b under acidic conditions is stereospecific and leads to threo-[(RR, SS)-4u] and erythro-5-hydroxy-4-octanesulfonic acid [(RS, SR)-4u], respectively, by a similar SN 2 reaction on the carbon of the C [BOND] O ...