Asymmetric one-pot synthesis of trans-stilbene oxide via desymmetrizing monosulfonylation of meso-hydrobenzoin catalyzed by a chiral bisoxazoline–copper (II) complex

Chiral stilbene oxides are useful and versatile intermediates for the synthesis of chiral ligands for asymmetric catalysis, chiral auxiliaries for diastereoselective transformations, and precursors for chiral building blocks of many compounds. We achieved the enantioselective desymmetric tosylation of meso-hydrobenzoin catalyzed by a chiral ligand–CuCl₂ complex followed by base promoted intramolecular cyclization to furnish trans-stilbene oxide in high yield with excellent enantioselectivity up to 99 %ee in a one-pot operation. This simple transformation offers the most feasible and promising option for the asymmetric synthesis of stilbene oxides with high optical purity.