Chiral catalysts for enantioselectively epoxidizing a prochiral olefin and for enantioselectively oxidizing a prochiral sulfide are disclosed, together with methods of using such catalysts. In accordance with one aspect of the invention, the catalyst is a salen derivative which has general structure (I). In accordance with another aspect of the present invention is a method of producing an epoxychroman using a chiral catalyst. In accordance with this method, a chromene derivative, an oxygen atom source, and a chiral catalyst are reacted under such conditions and for such time as is needed to epoxidize said chromene derivative. In accordance with yet another aspect of this invention is a method of enantioselectively epoxidizing a cis-cinnamate derivative to make taxol or an analog thereof. In accordance with another aspect a method of disproportionation of hydrogen peroxide using the catalysts of the present invention is disclosed.