IX. Mono- and biphasic asymmetric hydroformylation with rhodium catalysts of the diphosphine ligand NAPHOS and its sulfonated derivatives

Article abstract of DOI:10.1016/S0022-328X(96)06745-9

Both enantiomers of the diphosphine 2,2′-bis(diphenylphosphinomethyl)-1,1′-binaphthyl NAPHOS were prepared by resolution of the racemic P,P′-dioxide and subsequently applied in the rhodium-catalyzed, asymmetric hydroformylation of styrene. Optically active, highly water-soluble derivatives BINAS were prepared by direct sulfonation of the enantiopure diphosphine NAPHOS and applied in aqueous/organic, two-phase hydroformylation of styrene. The catalytically active rhodium complexes HRh(CO)₂(P-P) of both NAPHOS and BINAS were prepared and characterized by infrared and NMR spectroscopy. Optical yields are lower in two-phase hydroformylation compared with the conventional single-phase (organic solvent) technique.