Quest for Efficient Catalysts based on Zinc tert-Butyl Peroxides for Asymmetric Epoxidation of Enones: C2- vs C1-Symmetric Auxiliaries

Zinc <em>tert</em>-butyl peroxide-based catalysts for the asymmetric epoxidation of enones using <em>tert</em>-butyl hydroperoxide as an oxidant have been developed. A comparative study of chiral monoanioninc <em>N</em>,<em>N′</em>-bidentate ligands, <em>C2</em>-symmetric bisoxazolinates and <em>C1</em>-symmetric enaminooxazolinates, revealed excellent performance of <em>C1</em>-symmetric auxiliary ligands on catalytic asymmetric epoxidation of enones (up to 96% yield, 91% <em>ee</em>)