Highly Enantioselective Michael Addition of Silyl Nitronates to α,β-Unsaturated Aldehydes Catalyzed by Designer Chiral Ammonium Bifluorides: Efficient Access to Optically Active γ-Nitro Aldehydes and Their Enol Silyl Ethers
作者:Takashi Ooi、Kanae Doda、Keiji Maruoka
DOI:10.1021/ja0352810
日期:2003.7.1
Highly enantioselective Michael addition of silyl nitronates to α,β-unsaturated aldehydes has been accomplished by the utilization of designer N-spiro C2-symmetric chiral quaternary ammonium bifluoride 1 as an efficient catalyst, providing direct access to both optically active γ-nitro aldehydes, a very useful precursor to various complex organic molecules including aminocarbonyls, and their enol silyl
通过利用设计师 N-螺 C2-对称手性季铵二氟化物 1 作为有效催化剂,将硝基甲硅烷基酯与 α,β-不饱和醛进行高度对映选择性迈克尔加成,可直接获得具有旋光活性的 γ-硝基醛,一种非常有用的各种复杂有机分子的前体,包括氨基羰基化合物及其烯醇甲硅烷基醚,一种具有潜在合成效用的 Mukaiyama 供体,可用于进一步的选择性转化。例如,硝基三甲基甲硅烷基酯 2(R1 = Me)与反式肉桂醛(R2 = Ph,R3 = H)在 (R,R)-1 (2 mol %) 存在下在甲苯中的反应在 -78 时顺利进行°C 得到所需的烯醇甲硅烷基醚 3 (R1 = Me, R2 = Ph, R3 = H),分离产率为 90% (anti/syn = 83:17),ee (反异构体) 为 97%,