Application of P-stereogenic aminophosphine phosphinite ligands in asymmetric hydroformylation

New chiral aminophosphine phosphinite ligands with a stereogenic center at the aminophosphine phosphorus atom were prepared based on (R,S)-ephedrine a s the chiral auxiliary and backbone. Substituents at the chiral aminophosph ine as well as at the phosphinite phosphorus atom were varied. These new li gands were applied to the rhodium-catalyzed asymmetric hydroformylation of vinyl arenes, The enantiomeric excess reached up to 77%. H-1 and P-31 NMR s tudies of the Rh complexes under syngas pressure reveal that [HRh(CO)(2)((P P)-P-boolean AND)] complexes with the NP* moiety in an axial position are r esponsible for enantioselectivity.