Optically active a-arylalkylamines are an important class of compounds that are widely used in organic and pharmaceutical synthesis, and much effort has been made to develop efficient asymmetric synthetic methods for them. [1] Asymmetric catalytic hydrogenation of enamides, initiated by Kagan et al., [2] provides a direct and convenient route to chiral amine derivatives. However, many well-known chiral diphosphane ligands, such as DIOP, BINAP, and CHIRAPHOS, which are extremely successful in the asymmetric hydrogenation of dehydroamino acid derivatives, do not give high enantioselectivity in the hydrogenation of enamides.[3, 4] A breakthrough was achieved by Burk et al. [4a] with the introduction of BPE and DuPHOS ligands, which gave excellent enantioselectivity in the Rh-catalyzed asymmetric hydrogenation of enamides. Lately, some other P ligands were also reported to be efficient in the hydrogenation of enamides. [4b, 5] However, all ligands that gave a high degree of enantiocontrol are bidentate. To our knowledge, no efficient chiral monodentate ligand has been reported for the asymmetric hydrogenation of enamides, although some monodentate P ligands were successfully used in the hydrogenation of dehydroamino acid derivatives. [6] Here we describe highly efficient monodentate chiral ligands 1 containing a 1,1 -spirobiindane backbone for the Rh-catalyzed asymmetric hydrogenation of -arylethenylamine derivatives [Eq. (1)] with excellent enantioselectivities (up to 99.7% ee).