PipPhos and MorfPhos: Privileged Monodentate Phosphoramidite Ligands for Rhodium-Catalyzed Asymmetric Hydrogenation

A library of 20 monodentate phosphoramidite ligands has been prepared and applied in rhodium-catalyzed asymmetric hydrogenation. This resulted in the identification of two ligands, PipPhos
and MorfPhos, that afford excellent and in several cases unprecedented enantioselectivities in the
hydrogenation of N-acyldehydroamino acid esters, dimethyl itaconate, acyclic N-acylenamides, and
cyclic N-acylenamides. In addition, a method for the parallel enantioselectivity determination of
eight acylated amines is presented.

本研究制备了包含20种单齿亚磷酰胺配体（monodentate phosphoramidite ligands）的配体库，并将其应用于铑催化不对称氢化（rhodium-catalyzed asymmetric hydrogenation）反应。通过该实验体系，最终鉴定得到两种配体PipPhos与MorfPhos，二者在N-酰基脱氢氨基酸酯、衣康酸二甲酯、非环状N-酰基烯酰胺以及环状N-酰基烯酰胺的氢化反应中均展现出优异的对映选择性，在部分底物中甚至实现了前所未有的对映选择性水平。此外，本研究还提出了一种可用于八种酰化胺平行对映选择性测定的方法。