The Sharpless Epoxidation allows the enantioselective epoxidation of prochiral allylic alcohols. The asymmetric induction is achieved by adding an enantiomerically enriched tartrate derivative.
Mechanism of the Sharpless Epoxidation
The oxidant for the epoxidation is tert-Butyl hydroperoxide. The reaction is catalyzed by Ti(OiPr)4, which binds the hydroperoxide, the allylic alcohol group, and the asymmetric tartrate ligand via oxygen atoms (putative transition state depicted below).