Phosphine ligands with triamine functionality - preparation and application in catalysis

Sammanfattning: Incorporation of the triamine, bis(2-diethylaminoethyl) amine as a side chain substituent on triphenylphosphine, (2S,4S)-4-diphenylphosphino-2-diphenylphosphino-methylpyrrolidine (PPM) or (R,R)-3,4-bis(diphenylphosphin)pyrrolidine (Pyrphos) gives the three new amphiphilic ligands N3P, N3PPM and N3-Pyrphos respectively. Because of the triamine functionality the distribution of the ligands and their complexes between water and an organic solvent is controlled by the pH of the aqueous phase. pH controlled phase distribution properties can be utilised in catalyst recovery and recycling. Reaction of N3P with [Rh(CO)2(acac)] gives an active hydroformylation catalyst, which can be applied in neat toluene, in a biphasic solvent system or immobilised on zirkonium phosphate. A protocol employing HCl and NaBPh4 in the recycling of the hydroformylation catalyst increases its retained activity substantially. Reaction of N3P with [PdCl2(PhCN)2] gives a complex which is an active catalyst in aqueous phase hydrocarboxylation of styrene, 1-octene and 4-pentenoic acid. Hydrocarboxylation of styrene gives mainly the linear acid and the activity is maintained over four consecutive runs upon recycling of the catalyst Reaction of N3-PPM or N3-Pyrphos with [Rh(NBD)2]BF4 give the complexes [Rh(NBD)N3-PPM] and [Rh(NBD)N3-Pyrphos], respectively. Both complexes are active catalysts in enantioselective hydrogenation of various pro-chiral olefins using water as solvent or in the SAPC mode. The enantioselectivity of the catalysts in water is close to that of catalyst based on the parent PMM and pyrphos ligands in organic solvent