Remarkable effect of tris(4-fluorophenyl)phosphine oxide on the stabilization of chiral lanthanum complex catalysts. A new and practical protocol for the highly enantioselective epoxidation of conjugated enones.

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.