Laboratory of Biocatalysis and Synthetic Biotechnology, State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Road, 200237, Shanghai, PR China.
Angew Chem Int Ed Engl. 2024 Nov 18;63(47):e202408686. doi: 10.1002/anie.202408686. Epub 2024 Oct 22.
β-Branched chiral amines with contiguous stereocenters are valuable building blocks for preparing various biologically active molecules. However, their asymmetric synthesis remains challenging. Herein, we report a highly diastereo- and enantioselective biocatalytic approach for preparing a broad range of β-branched chiral amines starting from their corresponding racemic ketones. This involves a dynamic kinetic resolution-asymmetric reductive amination process catalyzed using only an imine reductase. Four rounds of protein engineering endowed wild-type PocIRED with higher reactivity, better stereoselectivity, and a broader substrate scope. Using the engineered enzyme, various chiral amine products were synthesized with up to >99.9 % ee, >99 : 1 dr, and >99 % conversion. The practicability of the developed biocatalytic method was confirmed by producing a key intermediate of tofacitinib in 74 % yield, >99.9 % ee, and 98 : 2 dr at a challenging substrate loading of 110 g L. Our study provides a highly capable imine reductase and a protocol for developing an efficient biocatalytic dynamic kinetic resolution-asymmetric reductive amination reaction system.
β-支链手性胺具有连续的立体中心，是制备各种生物活性分子的有价值的构建块。然而，它们的不对称合成仍然具有挑战性。在此，我们报告了一种从相应的外消旋酮起始，通过仅使用亚胺还原酶，高非对映选择性和对映选择性地制备广泛的β-支链手性胺的生物催化方法。这涉及使用亚胺还原酶催化的动态动力学拆分-不对称还原胺化过程。四轮蛋白质工程赋予野生型 PocIRED 更高的反应性、更好的立体选择性和更广泛的底物范围。使用工程化酶，各种手性胺产物的合成产率高达>99.9%ee、>99:1dr 和>99%转化率。通过在具有挑战性的 110g/L 底物负载下以 74%的产率、>99.9%ee 和 98:2dr 生产托法替尼的关键中间体，证实了所开发的生物催化方法的实用性。我们的研究提供了一种高活性的亚胺还原酶和一种开发高效生物催化动态动力学拆分-不对称还原胺化反应体系的方案。
