Single Enantiomer Epoxides by Bromomandelation of Prochiral Alkenes

A combination of mandelic acid and N-bromosuccinimide efficiently converts prochiral alkenes into a
readily separable 1:1 mixture of the bromomandelates. The diastereomerically pure bromomandelates
are then converted into a variety of enantiomerically pure products. Terminal alkenes are converted into
enantiomerically pure epoxides. Cyclohexene is converted into enantiomerically pure cis-2-azidocyclohexanol and cis-2-phenylthiocyclohexanol.