The transition metal-catalyzed asymmetric hydrogenation utilizing molecular hydrogen to reduce prochiral unsaturated bonds is one of the most efficient and atom-economic methods for the preparation of optically active compounds. The chiral spiro ligands including bidentate phosphines SDPs, phosphine-oxazolines SIPHOXs, amino-phosphines SpiroAP, phosphine-amino-pyridines SpiroPAP, phosphine-amino-phosphines SpiroPNP, and monodentate phosphorous ligands (SIPHOS and FuPs) exhibited high activity and excellent enantioselectivity for the rhodium-, ruthenium- and iridium-catalyzed asymmetric hydrogenations of functionalized olefins (including enamides, enamines, and α,β-unsaturated carboxylic acids), ketones, aldehydes, and imines.

n Rh(I)-SIPHOS/Rh(I)-FuP complexes catalyzed asymmetric hydrogenation of enamides

n Ru(II)-SDP complexes catalyzed asymmetric hydrogenation of ketones

n Ru(II)-SDP complexes catalyzed asymmetric hydrogenation of racemic α-substituted aldehydes and ketones via DKR

n Ir(I)-SIPHOX complexes catalyzed asymmetric hydrogenation of enamines

n Ir(I)- SIPHOX complexes catalyzed asymmetric hydrogenation of α,β-unsaturated acids

n Ir(I)-PAP/Ir(I)-PNP complexes catalyzed asymmetric hydrogenation of ketones

n Ir(I)- SIPHOX complexes catalyzed asymmetric hydrogenation of imines