Metachloroperbenzoic acid ($m\text{-}\mathrm{Cl}{\mathrm{C}}_6{\mathrm{H}}_4\mathrm{C}(\mathrm{O})\mathrm{OOH}$)

Metachloroperbenzoic acid is a peroxycarboxylic acid used for concerted oxygen transfer to alkenes. A neighboring allylic hydroxyl can direct its approach through hydrogen bonding.