A highly efficient and practical method for obtaining alpha,beta-epoxy ketones with high optical purities was developed. The chiral lanthanum complex self-organized in situ from lanthanum triisopropoxide, (R)-BINOL, triarylphosphine oxide, and alkyl hydroperoxide (1:1:1:1) was found to catalyze the epoxidation of alpha,beta-unsaturated ketones with tert-butyl hydroperoxide or cumene hydroperoxide at room temperature to give the corresponding epoxy ketones in high enantioselectivities (up to >99% enantiomeric excess (ee)). A remarkably high asymmetric amplification, a positive nonlinear effect, was observed in the epoxidation of chalcone, which strongly suggests the formation of a dinuclear peroxide-involved mu-complex as the active catalyst.

A new and efficient chiral catalyst system, lanthanum-chiral BINOL-tris(4-fluorophenyl)phosphine oxide-cumene hydroperoxide, was developed for the epoxidation of alpha, beta-unsaturated ketones thus providing the corresponding epoxy ketones with excellent enantioselectivities (up to >99% ee) in good to excellent yields at room temperature.

Highly Enantioselective Epoxidation of Conjugated Enones. -(KINO, R.; DAIKAI, K.; KAWANAMI, T.; FURUNO, H.; INANAGA*, J.; Org. Biomol. Chem. 2 (2004) 13, 1822-1824; Dep. Mater. Chem. Eng., Kyushu Univ., Hakozaki, Fukuoka 812, Japan; Eng.) -Nuesgen 44-055