Optically active phosphorous compounds

The present invention is concerned with novel optically active phosphorus compounds of the general formula I wherein R and R1 each independently signify hydroxy, a protected hydroxy group, lower alkyl or lower alkoxy and R2 to R5 each independently signify alkyl with 3 to 7 carbon atoms, cycloalkyl or aryl or R2 and R3 or R4 and R5 together with the phosphorus form a group of the formula wherein R2 and R3 are different when R4 and R5 are the same, and R4 and R5 are different when R2 and R3 are the same, the manufacture of such compounds, their use for enantioselective reactions, such as, e.g., asymmetric hydrogenations, enantioselective hydrogen displacements in prochiral allylic systems and the like, as well as complexes of the compounds of formula I with Group VIII metals.