Enantioselective copper-catalyzed conjugate additions of in situ generated organozirconium reagents to N -heterocyclic Michael acceptors
作者:Ivana Némethová、Stanislav Bilka、Radovan Šebesta
DOI:10.1016/j.jorganchem.2017.12.042
日期:2018.2
Stereoselective conjugate additions of organometallic reagents provide access to many useful chiral compounds. In this work, we have studied the enantioselective Cu-catalyzed conjugate addition of organozirconium reagents, which were generated in situ by hydrozirconation of alkenes. We show that N-heterocyclic Michael acceptors, represented by unsaturated lactams and 2,3-dihydropyridin-4(1H)-ones can
有机金属试剂的立体选择共轭物的添加提供了许多有用的手性化合物的途径。在这项工作中,我们研究了有机锆试剂的对映选择性Cu催化的共轭加成反应,该反应是通过烯烃的加氢锆现场生成的。我们显示N-杂环Michael受体,代表不饱和内酰胺和2,3-二氢吡啶-4(1 H-一个可以用作有机锆试剂的铜催化的共轭加成的有用底物。磷配体的筛选确定了Feringa的亚磷酰胺是该转化过程中最具活性和对映选择性的配体,它提供了对映体纯度高达92:8 er的相应的共轭加成产物。通过比较DFT,确定了一种共轭加成产物的绝对构型计算和实验电子CD光谱。该研究还表明,轻度反应性有机锆试剂与相对不反应的迈克尔受体结合通常可以以中等收率提供共轭加成产物。LUMO图的DFT计算也支持杂环迈克尔受体的非反应性。