trans-Stilbene undergoes epoxidation with a two-fold excess of sodium periodate in the presence of 2 mol% ruthenium( II)
2-( phenylazo)pyridine complexes. Selectivities for epoxide are in the range 34-75%. depending on the structure of the complex.
The byproduct. benzaldehyde, is derived from competing oxidative cleavage of the double bond.