Synthesis of Atropisomeric 2,2′-Bis(dicyclohexylphosphino)-6,6′-dimethyl-1,1′-biphenyl (BICHEP) and Its Use in Rh(I)-catalyzed Asymmetric Hydrogenation of Prochiral Olefins

The atropisomeric bis(dialkylarylphosphine) ligands, (R)-(−)- and (S)-(+)-2,2′-bis(dicyclohexylphosphino)-6,6′-dimethyl-1,1′-biphenyl (BICHEP) (1) have been newly synthesized, whose Rh(I) complexes are highly efficient catalysts for asymmetric hydrogenations of ethyl α-(benzamido)cinnamate and dimethyl itaconate in up to 98% yields and 98–99% enantiomeric excess.