Non-C2-symmetric bisphosphine ligands as catalysts for asymmetric hydrogenation

A non-C2 symmetric bisphosphine ligand comprising an achiral phosphine group, a chiral phosphine group, and a bridge that links the achiral and chiral phosphine groups, the ligand represented by Formula I:

• or corresponding enantiomers thereof, wherein:
• the bridge is substituted or unsubstituted C1-12 alkylene or aryl;
• the achiral phosphine group is
• in which R is the same at each occurrence and is isopropyl, tert-butyl, 1,1-dimethylpropyl, 1,1-diethylbutyl, 1,1,3,3-tetramethylbutyl, cyclopentyl, 1-methyl-cyclopentyl, 1-methyl-cyclohexyl, 1-hydroxy-C5-15-cycloalkyl, 1-alkoxy-C5-15-cycloalkyl, adamantyl, dialkylamino, or diarylamino;
• and
• the chiral phosphine group is
• in which
• R5 is isopropyl, tert-butyl, 1,1-dimethylpropyl, 1,1-diethylbutyl, 1,1,3,3-tetramethylbutyl, 1-methyl-cyclopentyl, 1-methyl-cyclohexyl, C5-15-cycloalkyl, 1-hydroxy-C5-15-cycloalkyl, 1-alkoxy-C5-15-cycloalkyl, dialkylamino, or diarylamino;
• and
• R1 is hydrogen, methyl, straight chain alkyl or substituted alkyl of up to twenty carbon atoms, alkoxy or substituted alkoxy of up to twenty carbon atoms, alkylamino, or arylamino, provided that R1 and R5 are different.