New Auxiliaries for Copper-Catalyzed Asymmetric Michael Reactions: Generation of Quaternary Stereocenters at Room Temperature
作者:Jens Christoffers、Alexander Mann
DOI:10.1002/1521-3765(20010302)7:5<1014::aid-chem1014>3.0.co;2-x
日期:2001.3.2
Dialkyl amides of L-valine, L-isoleucine, and L-tert-leucine (2) are excellent chiral auxiliaries for the construction of quaternary stereocenters at ambient temperature. Enaminoesters 3, prepared from these auxiliaries 2 and Michael donors 1, undergo a copper-catalyzed asymmetric Michael reaction with methyl vinyl ketone (MVK, 4) to afford products 5 in 70-90% yield and 90-99% ee (enantiomeric excess)
L-缬氨酸、L-异亮氨酸和 L-叔亮氨酸 (2) 的二烷基酰胺是在环境温度下构建四元立体中心的极佳手性助剂。由这些助剂 2 和迈克尔供体 1 制备的烯胺酯 3 与甲基乙烯基酮 (MVK, 4) 进行铜催化的不对称迈克尔反应,以 70-90% 的产率和 90-99% 的 ee(对映体过量)提供产物 5 . 不需要排除水分或氧气。助剂2可通过标准程序容易地获得。后处理后,它们几乎可以定量回收。