Chiral α-aryl glycines play a key role in the preparation of some bioactive products, however, their catalytic asymmetric synthesis is far from being satisfactory. Herein, we report an efficient nickel-catalyzed asymmetric hydrogenation of N-aryl imino esters, affording chiral α-aryl glycines in high yields and enantioselectivities (up to 98% ee). The hydrogenation can be conducted on a gram scale with a substrate/catalyst ratio of up to 2000. The obtained chiral N-p-methoxyphenyl α-aryl glycine derivatives are not only directly useful chiral secondary amino acid esters but can also be easily deprotected by treatment with cerium ammonium nitrate for further transformations to several widely used molecules including drug intermediates and chiral ligands. Formation of a chiral Ni-H species in hydrogenation is detected by ¹H NMR. Computational results indicate that the stereo selection is determined during the approach of the substrate to the catalyst.

手性α-芳基甘氨酸在一些生物活性产品的制备中发挥着关键作用，然而其催化不对称合成还远远不能令人满意。在此，我们报道了一种有效的镍催化N-芳基亚氨基酯的不对称氢化，以高产率和对映选择性（高达 98% ee）提供手性 α-芳基甘氨酸。氢化反应可以在克级规模上进行，底物/催化剂比高达2000。所得手性N-对甲氧基苯基α-芳基甘氨酸衍生物不仅是直接可用的手性仲氨基酸酯，而且可以很容易地通过用硝酸铈铵处理，进一步转化为几种广泛使用的分子，包括药物中间体和手性配体。通过¹ H NMR 检测氢化过程中手性 Ni-H 物质的形成。计算结果表明立体选择是在底物接近催化剂的过程中确定的。