Efficient access to chiral dihydrobenzoxazinones via Rh-catalyzed hydrogenation.

Rh/( S )-DTBM-SegPhos-catalyzed asymmetric hydrogenation of prochiral ( Z )-2-(2-oxo-2 H -benzo[ b ][1,4]oxazin-3(4 H )-ylidene)acetate esters was successfully developed. A series of chiral dihydrobenzoxazinones were prepared through this efficient methodology with good to excellent results (up to >99% conversion, 93% yield and >99% ee), which are important motifs in the biologically active molecules.