Compounds of the formula (I), in the form of mixtures comprising predominantly one diastereomer or in the form of pure diastereomers, Z1-Q-P*R0R1 (I) in which Z1 is a C-bonded, secondary phosphine group —P(R)2; in which R is in each case independently hydrocarbon radicals or heterohydrocarbon radicals, or Z1 is the —P*R0R1 group; Q is a bivalent, achiral, aromatic base skeleton, a bivalent, achiral ferrocene base skeleton, an optionally substituted bivalent cycloalkane or heterocycloalkane skeleton, or a C1-C4-alkylene skeleton, and in which base skeletons a secondary phosphine group Z1 is bonded directly to a carbon atom, or, in the case of cyclic base skeletons, directly to a carbon atom or via a C1-C4-alkylene group, and in which base skeletons a P-chiral group —P*R0R1 is bonded directly to a carbon atom, or, in the case of cyclic base skeletons, directly to a carbon atom or via a C1-C4-alkylene group to a carbon atom such that the phosphorus atoms are linked via 1 to 7 atoms of a carbon chain optionally interrupted by heteroatoms from the group of O, S, N, Fe or Si; P* is a chiral phosphorus atom; R0 is methyl or hydroxyl, and R0 is methyl when Z1 is the —P*R0R1 group; and R1 is a C-bonded optically enriched or optically pure chiral, mono- or polycyclic, nonaromatic hydrocarbon or heterohydrocarbon radical which has 3 to 12 ring atoms and 1 to 4 rings and which has a stereogenic carbon atom at least in the a position to the P—C bond; Metal complexes of these ligands are homogeneous catalysts for asymmetric addition reactions, particularly hydrogenations.