ORGN 595

Recently, enantiopure monophosphite ligands bearing axially chiral biphenol were developed in our laboratories and they showed excellent enantioselectivity in Rh(I)-catalyzed asymmetric hydrogenation reactions. The ortho substituent R² of the biphenol moiety and the counterion of rhodium species exhibited dramatic effects on enantioselectivity and the configuration of products in the hydrogenation of dimethyl itaconate. We report here a detailed study on the active catalyst species and the effects of ortho substituent of biphenol on enantioselectivity as well as the activity of the catalyst. Applications of these tunable chiral monophosphite and monophosphoramidite ligands on enantioselective hydrogenation, hydroformylation, 1,4-addition and allylic substitution reaction will be discussed.