What about BOB? A synthetically useful protecting group

Benzyloxybutyryl (BOB) esters of alcohols can be prepared from commercially available 4-benzyloxybutyric acid by standard acylation techniques, by the Mitsunobu reaction (with inversion of configuration), or by the Jacobsen asymmetric nucleophilic ring opening of epoxides. BOB esters can be removed selectively in the presence of other esters under conditions that are compatible with a variety of sensitive functional groups.