Access to -chiral - and -phosphine oxides enabled by Le-Phos-catalyzed asymmetric kinetic resolution.

The synthesis of -stereogenic building blocks is extremely difficult. Herein we report an efficient kinetic resolution of secondary phosphine oxides a Le-Phos-catalyzed asymmetric allylation reaction with Morita-Baylis-Hillman carbonates. This method provides facile access to enantioenriched secondary and tertiary -chiral phosphine oxides with broad substrate scope, both of which could serve as -stereogenic synthons, and can be rapidly incorporated into a given scaffold bearing a -stereocenter. The highly desirable late stage modifications demonstrate the practicability of our method and can be a critical contribution to obtaining optimal -chiral catalysts and ligands.