Chiral 1,2,3,4-tetrahydro-1-naphthylamine-derived phosphine-phosphoramidite ligand (THNAPhos): Application in highly enantioselective hydrogenations of functionalized C=C bonds

We have recently reported a new chiral 1,2,3,4-tetrahydro-1-naphthylamine-derived phosphine-phosphoramidite ligand, (R-c,R-a)-THNAPhos, that is highly efficient in the rhodium-catalyzed asymmetric hydrogenation of a broad range of alpha-enol ester phosphonates. To further demonstrate the utility of THNAPhos in asymmetric hydrogenation, in this paper, we describe its new application in the asymmetric hydrogenation of alpha-dehydroamino acid esters, enamides, dimethyl itaconate and alpha-enamido phosphonates. The results disclosed that the Rh/(R-c,R-a)-THNAPhos complex is highly effective for the enantioselective hydrogenation of these kinds of functionalized C=C olefins, affording the corresponding hydrogenation product in excellent enantioselectivities (normally over 99% ee).