Process for the preparation of bisphosphines.

A method of manufacturing a compound of general formula (R3-C)2P-L1-X-L2-P-(C-R3)2, in which each R is independently a pendant, optionally substituted, organic group through which the group is linked to tertiary carbon atom C; L1, L2 are independently a linking group selected from an optionally substituted lower alkylene chain connecting the respective phosphorus atom to the group X and X is a bridging group comprising an optionally substituted aryl moiety to which the phosphorus atoms are linked on available adjacent carbon atoms, comprises: i) reacting together a compound of formula H-L1-X-L2-H with an organometallic compound to form an intermediate compound of formula M-L1-X-L2-M, where M is an alkali metal atom; ii) reacting said intermediate compound with a compound of formula (R3-C)2P-A, where A is a halogen atom, to form said compound of general formula (R3-C)2P-L1-X-L2-P-(C-R3)2, M is preferably lithium, potassium or sodium and the intermediate compound may be isolated or not. The reaction (i) may advantageously be carried out in the presence of a complexing agent such as tetramethyethylenediamine.