Enantioselective Epoxidation of Isoflavones by Jacobsen′s Mn(III)Salen Catalysts and Dimethyldioxirane Oxygen-Atom Source.

Abstract The catalytic enantioselective epoxidation of the isoflavones 1a–f has been performed by the Mn(III)salen complexes (R,R)-3 and (S,S)-3 as catalysts and dimethyldioxirane as the oxygen-atom source to afford optically active isoflavone epoxides 2a–f. The absolute configuration of the nonracemic epoxides 2 have been determined by X-ray diffraction analysis. Our present results constitute the first examples of the preparation of optically active isoflavone epoxides.