Synthese und Eigenschaften hydrophiler Arylphosphate

This work presents a new and efficient approach to hydrophilic aromatic phosphines, the palladium-catalyzed P-C coupling reaction. By coupling of primary and secondary phosphines with a great variety of different functionalized aromatic halocarbons a number of novel phosphines ( 12 , 14 - 32 , 34 ) bearing electron rich (-NH 2 , -OH, -CH 3 ) as well as electron poor substituents (-COOR, -COOH, -SO 3 H) are accessible. Even multifunctional phosphines with a combination of equal (e. g. 24 , 30 ) or different substituents (e. g. 25 , 27 ) at the aromatic groups can be obtained in good to high yields. The required catalyst concentrations are low (0.05-0.2 mol%), and no formation of side products is observed. The coupling reactions of Ph 2 PH with aromatic halocarbons can simply be initiated by addition of Pd(OAc) 2 as a precatalyst, whereas the corresponding reactions of PhPH 2 need Pd(0) complexes that contain chelating phosphine ligands as a catalyst. It has been shown that a solution of Pd(dba)dppp, which is easily prepared in situ of Pd(dba) 2 and dppp, is satisfying for that purpose. In contrast to alternative methods the Pd-catalysed coupling of primary phosphines like PhPH 2 with one equivalent of an aromatic halocarbon (e. g. 3-iodo-4-methylbenzoic acid) offers a direct route to secondary phosphines like 34 without the need of protecting groups at the phosphorus atom or excess of the educt phosphine. Further reaction of 34 with 3-iodobenzoic acid yields the p-chiral phosphine 35 . Reaction of 5-diphenylphosphinosalicylic acid 16 with phenylboronic acid affords 36 , an interesting ligand with a Lewis acceptor function at the boron atom. In the presence of NEt 4 OH 16 is converted by B(OH) 3 into the chiral bidentate phosphine 37 which forms with [(nor)RhCl] 2 the chiral binuclear Rhodium complex 44 . Reactions of the sulfonated phosphine ligands 38 and 39 with the Rhodium precursors [Rh(CO) 2 Cl)] 2 and [Rh(C 2 H 4 ) 2 Cl)] 2 in the biphasic medium toluene/H 2 O lead to the hydrophilic Rhodium complexes 40 - 43 , the latter being a water soluble derivative of the Wilkinson catalyst. The catalytic properties of a selection of the obtained phosphine ligands ( 12 , 13 , 17 , 18 , 30 ) under the conditions of the Shell Higher Olefin Process have been investigated, showing 5-diphenylphosphinoanthranilic acid 18 being able to form an active catalyst. The synthesized compounds were characterized by 1 H-, 13 C- and 31 P-NMR spectroscopy, elemental analyses , IR- and mass spectra. The structures of 16 and 33 have been determined by X-ray crystallography.