SYNTHESIS OF NEW CHIRAL PHOSPHINEPHOSPHITES HAVING 2-DIPHENYLPHOSPHINOBIPHENYL-2'-YL BACKBONE AND THEIR USE IN RH(I)-CATALYZED ASYMMETRIC HYDROFORMYLATIONS

New chiral phosphinephosphites l-2'-yl)((S)-1,1'-binaphthalen-2,2'-diy l)phosphite [abbreviated (R,S)-BIPHEMPHOS] and its enantiomer (S,R)-BI PHEMPHOS have been synthesized from '-dichloro-4,4',6,6'-tetramethyl-2 ,2'-biphenyldiol in enantiomerically pure form. Their Rh(I) complexes have been shown to be highly efficient catalysts for asymmetric hydrof ormylations of a variety of olefinic substrates. The corresponding pho sphinephosphites derived from 2,2'-biphenyldiol were also tested as li gands for asymmetric hydroformylation.