Kinetic Resolution of α-Bromoamides: Experimental and Theoretical Investigation of Highly Enantioselective Reactions Catalyzed by Haloalkane Dehalogenases
作者:Alja Westerbeek、Wiktor Szymański、Hein J. Wijma、Siewert J. Marrink、Ben L. Feringa、Dick B. Janssen
DOI:10.1002/adsc.201000726
日期:2011.4.18
Haloalkane dehalogenases from five sources were heterologously expressed in Escherichia coli, isolated, and tested for their ability to achieve kinetic resolution of racemic α‐bromoamides, which are important intermediates used in the preparation of bioactive compounds. To explore the substrate scope, fourteen α‐bromoamides, with different Cα‐ and N‐substituents, were synthesized. Catalytic activity
来自五个来源的卤代烷脱卤酶在大肠杆菌中异源表达,分离并测试了其实现外消旋α-溴代酰胺动力学拆分的能力,这是用于制备生物活性化合物的重要中间体。探索底物范围,14α-bromoamides,具有不同Ç α-和Ñ -取代基,合成的。发现了对八种底物的催化活性,并且对于这些化合物中的五种,转化以高对映选择性(E值> 200)进行。在所有情况下,(R)-α-溴酰胺是首选的底物。在制备规模上用催化量的酶进行转化(酶:底物比例小于1:50 w / w)均在17-46 h内完成,分离出光学纯的α-溴酰胺和α-羟酰胺,收率很高(31- 50%)。底物对接,随后进行分子动力学模拟表明,高对映选择性是由底物对映异构体有利地结合用于催化的时间百分比不同引起的。对于首选(R底物,酶的进攻性天门冬氨酸氧原子,酶的进攻性碳原子与被取代的卤素原子之间的夹角通常在反应性的最佳范围内(> 157°)。这可以解释在动力学拆分