The invention relates to compounds having a structural element of formula
(I) in an aromatic hydrocarbon ring, wherein: M represents --Li,
--MgX.sub.3, (C.sub.1-C.sub.18-Alkyl).sub.3Sn--, --ZnX.sub.3 or
--B(O--C.sub.1-C.sub.4-Alkyl).sub.2; X.sub.1 and X.sub.2, independent of
one another, represent O or N, and C-bound hydrocarbon radicals or
heterohydrocarbon radicals are bound to the free bonds of the O and N
atoms; group --C.dbd.C--, together with C atoms, forms a hydrocarbon
aromatic compound and represents X.sub.3 Cl, Br or I. The inventive
compounds are easily obtained by directly substituting the hydrogen in
the ortho position to the P atom with metalation reagents. The metal
atoms can then be substituted by a reactive electrophilic compound. The
group --P(X.sub.1--)(X.sub.2--) - - - -(BH.sub.3).sub.0,1 can then be
converted into a secondary phosphine group. The inventive method enables
the production of monophosphines and diphosphines even on a large scale,
which are valuable ligands for metal complexes serving as catalysts for,
e.g. enantioselective hydrogenations. ##STR00001##