A practical method for enantioselective synthesis of all-carbon quaternary stereogenic centers through NHC-Cu-catalyzed conjugate additions of alkyl- and arylzinc reagents to β-substituted cyclic enones
A practical method for enantioselective synthesis of all-carbon quaternary stereogenic centers through NHC-Cu-catalyzed conjugate additions of alkyl- and arylzinc reagents to β-substituted cyclic enones
复制标题
DOI：
10.1021/ja062061o
复制
发表时间：
2006-06-07
影响因子：
15
通讯作者：
Hoveyda, Amir H.
中科院分区：
文献类型：
--
作者：
Lee, Kang-Sang;Brown, M. Kevin;Hoveyda, Amir H.
我们提出了铜催化的烷基和芳基锌试剂与未活化的环状 β-取代烯酮的对映选择性共轭加成的第一个例子。在 2.5−15 mol% 的手性 NHC 基铜配合物存在下，可促进转化，提供带有全碳四元立体中心的所需产物，产率 67→98%，ee 高达 97%。催化对映选择性反应可以在台式上使用未蒸馏的溶剂和市售（未进一步纯化）的铜盐进行。提供了解释观察到的对映选择性水平和趋势的机制模型。
We present the first examples of Cu-catalyzed enantioselective conjugate additions of alkyl- and arylzinc reagents to unactivated cyclic β-substituted enones. Transformations are promoted in the presence of 2.5−15 mol % of a readily available chiral NHC-based Cu complex, affording the desired products bearing all-carbon quaternary stereogenic centers in 67→98% yield and in up to 97% ee. Catalytic enantioselective reactions can be carried out on a benchtop, with undistilled solvent and commercially available (not further purified) Cu salts. Mechanistic models, accounting for the observed levels and trends in enantioselectivity are provided.