PALLADIUM-CATALYZED P-C COUPLING - A POWERFUL TOOL FOR THE SYNTHESES OF HYDROPHILIC PHOSPHINES

A new synthetic procedure for the preparation of hydrophilic phosphine s based on the palladium catalyzed P-C coupling of mono and multiply f unctionalized aromatic bromides and iodides with primary and secondary phosphines has been developed. In addition to multiply functionalized anionic phosphines and those bearing electron rich substituents like OH, NH2 cationic guanidinium type phosphine ligands are accessible by this method in high yields. The novel guanidinium phosphines are readi ly soluble in water showing a remarkable stability in a wide pH range. They turned out to be quite effective catalyst ligands in Rh catalyze d hydroformylation reactions and Pd catalyzed C-C coupling in two-phas e systems and aqueous solutions. (C) 1998 Elsevier Science B.V. All ri ghts reserved.