Compounds of formulae I and Ia, wherein X 1 is secondary phosphino; R 3 is hydrogen, a hydrocarbon radical having from 1 to 20 carbon atoms, a heterohydrocarbon radical, bonded via a carbon atom, having from 2 to 20 atoms and at least one hetero atom selected from the group O, S and NR, or ferrocenyl; R is H or C 1 -C 4 alkyl; each R 4 individually or both R 4 together are a hydrocarbon radical having from 1 to 20 carbon atoms; and R 01 and R 02 are each independently of the other a hydrogen atom or a hydrocarbon radical having from 1 to 20 carbon atoms, are chiral ligands for metal complexes with metals of sub-groups I and VIII, which are catalysts for asymmetric addition reactions, for example of hydrogen, to prochiral unsaturated organic compounds.