Stereodivergent Synthesis of Trisubstituted Enamides: Direct Access to Both Pure Geometrical Isomers
作者:Luca Massaro、Jianping Yang、Suppachai Krajangsri、Emanuele Silvi、Thishana Singh、Pher G. Andersson
DOI:10.1021/acs.joc.9b01803
日期:2019.11.1
either (E)- or (Z)-isomers of trisubstituted enamides. Starting from an extensive range of ketones, it was possible to synthesize and isolate the desired pure isomer by switching the reaction conditions. Lewis acid activation enables the formation of the (E)-isomers in high stereoselectivity (>90:10) and good yields. On the other hand, the use of a Brønsted acid allows the preparation of the (Z)-isomers
已经开发出立体发散策略以接近三取代的烯酰胺的(E)-或(Z)-异构体。从广泛的酮类开始,可以通过切换反应条件来合成和分离所需的纯异构体。路易斯酸活化使得能够以高立体选择性(> 90:10)和良好的产率形成(E)-异构体。另一方面,布朗斯台德酸的使用允许再次以高选择性(高达99:1)以中等收率制备(Z)-异构体。