Sharpless Epoxidation

The Sharpless Epoxidation allows the enantioselective epoxidation of prochiral allylic alcohols. The asymmetric induction is achieved by adding an enantiomerically enriched tartrate derivative.

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Mechanism

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).