Method for producing diphosphines and the use thereof

A process for preparing diphosphines of formula I

• R1R2P—H2C—Ar—CH2PR1R2 (I)
• which comprises:
• a) reacting a dim ethyl compound of formula II
• H3C—Ar—CH3 (II)
• with a base and an N-substituted aminophosphorus halide to form a bis(aminophosphinomethyl) compound of formula III
• R3R4P—H2C—Ar—CH2—PR3R4 (III)
• b) reacting the compound of formula III with HCl to form a bis(dichlorophosphinomethyl) compound of formula IV
• Cl2P—H2C—Ar—CH2—PCl2 (IV)
• and c) reacting the compound of formula IV with an organometallic reagent to give the product compound of formula I, wherein groups R1 and R2 are each, independently of one another, are:
• (i) heteroaromatics having a five-, six- or seven-membered ring and nitrogen, oxygen or sulfur atoms in the ring, where further aromatic, heteroaromatic and/or aliphatic rings are optionally fused onto the ring and the rings optionally bear up to seven substituents selected from the group consisting of (C1-C8)-alkyl, O-alkyl-(C1-C8), O-phenyl, phenyl, fluorine, chlorine, CN, COOH, CHO, SO3H, SO3alkyl-(C1-C6), SO-alkyl-(C1-C8), CF3, COO-alkyl-(C1-C8), COO-phenyl, PO-phenyl2, PO-alkyl2-(C1-C4), PO3H2, PO—(O-alkyl-(C1-C6))2, SO3-alkyl-(C1-C4);
• (ii) cyclic or acyclic alkyl radicals which contain up to 10 carbon atoms and optionally bear up to seven substituents selected from the group consisting of (C1-C8)-alkyl, O-alkyl-(C1-C8), O-phenyl, phenyl, fluorine, chlorine, CN, COOH, CHO, SO3H, SO2-alkyl-(C1-C6), SO-alkyl-(C1-C6), CF3, COO-alkyl-(C1 -C8), COO-phenyl, PO-phenyl2, PO-alkyl2-(C1-C4), PO3H2, PO—(O-alkyl-(C1-C8))2 and SO3-alkyl-(C1-C4);
• or
• (iii) aromatics having up to 14 carbon atoms and are able to bear up to eight substituents selected from the group consisting of (C1-C8)-alkyl, O-alkyl-(C1-C8), O-phenyl, phenyl, fluorine, chlorine, CN, COOH, CHO, SO3H, SO2-alkyl-(C1-C6), SO-alkyl-(C1-C8), CF3, COO-alkyl-(C1-C8), COO-phenyl, PO-phenyl2, PO-alkyl2-(C1-C4), PO3H2, PO—(O-alkyl-(C1-C6))2 and SO3-alkyl-(C1-C4), wherein, when the aromatic group is a substituted phenyl group, the phenyl group can not be substituted by fluorine, trifluoromethyl or C1-8-alkyl;
• and Ar is a substituted or unsubstituted aromatic or heteroaromatic hydrocarbon group and R3 and R4 are each, independently of one another, an N-substituted alkylamino or arylamino group.