Asymmetric Conjugate Addition to Cyclic Enone Catalyzed by Cu-NHC Complexes with C2 Symmetry
作者:Fengjun Shan、Lan Jiang、Zhengning Li、Defeng Zhao
DOI:10.1002/cjoc.201190198
日期:2011.5
A series of chiral, C2 symmetric tridentate N‐heterocyclic carbene precursors, containing two N‐functionalized hydroxyl or alkoxyl groups, were synthesized. They were applied to catalyze the asymmetric conjugate addition of diethylzinc to cyclohex‐2‐enone and cyclopent‐2‐enone. Enantioselectivity of corresponding reactions can be accomplished with up to 76% ee, and 65% ee, respectively. Flip of major
合成了一系列手性,C 2对称的三齿N-杂环卡宾前体,其中包含两个N-官能化的羟基或烷氧基。它们被用于催化二乙基锌向环己-2-烯酮和环戊-2-烯酮的不对称共轭加成反应。相应的反应的对映选择性可以分别通过高达76%ee和65%ee来实现。当使用不同的碱或铜源时,观察到主要对映异构体的翻转。