Direct Catalytic Asymmetric Michael Reaction of Hydroxyketones: Asymmetric Zn Catalysis with a Et<sub>2</sub>Zn/Linked-BINOL Complex
作者:Shinji Harada、Naoya Kumagai、Tomofumi Kinoshita、Shigeki Matsunaga、Masakatsu Shibasaki
DOI:10.1021/ja028928+
日期:2003.3.1
our direct Michael addition of unmodified ketones using new asymmetric zinc catalysis are described. Et(2)Zn/(S,S)-linked-BINOL complexes were successfully applied to direct 1,4-addition reactions of hydroxyketones. The first generation Et(2)Zn/(S,S)-linked-BINOL 1 = 2/1 system was effective for 1,4-addition of 2-hydroxy-2'-methoxyacetophenone (3). Using 1 mol % of (S,S)-linked-BINOL 1 and 2 mol % of
描述了我们使用新的不对称锌催化直接迈克尔加成未改性酮的全部细节。Et(2)Zn/(S,S)-linked-BINOL 配合物被成功应用于羟基酮的直接 1,4-加成反应。第一代 Et(2)Zn/(S,S)-linked-BINOL 1 = 2/1 系统对 2-羟基-2'-甲氧基苯乙酮的 1,4-加成有效 (3)。使用 1 mol% (S,S)-linked-BINOL 1 和 2 mol% Et(2)Zn,我们发现β-未取代烯酮的 1,4-加成反应在 4 摄氏度下顺利进行,得到产品高产率(高达 90%)和对映体过量(高达 95%)。然而,对于β-取代的烯酮,第一代Et(2)Zn/(S,S)-linked-BINOL 1 = 2/1 系统根本无效。第二代 Et(2)Zn/(S, S)-linked-BINOL 1 = 4/1 with MS 3A 系统被开发出来,对各种 β 取代的烯酮有效,以提供良好的产率、产率(高达