Generally, amine‐catalyzed enantioselective transformations rely on chiral enamine or unsaturated iminium intermediates. Herein, we report a protocol involving dual activation by an aromatic iminium and hydrogen‐bonding. An enantioselective aza‐Michael–Henry domino reaction of 2‐aminobenzaldehydes with nitroolefins has been developed through this protocol using primary amine thiourea catalysts to provide
通常,胺催化的对映选择性转化依赖于手性烯胺或不饱和亚胺中间体。在这里,我们报告了一个涉及芳香亚胺和氢键双重激活的协议。2-氨基苯甲醛与硝基烯烃的对映选择性氮杂-迈克尔-亨利多米诺反应已通过该方案使用伯胺硫脲催化剂开发,以中等收率和高达 90% ee提供各种 3-硝基-1,2-二氢喹啉. 通过反应中间体的 ESI 质谱检测证实了催化对映选择性反应的机制。形成的产物是在重要生物和药物分子的骨架中发现的亚结构。
Bifunctional thiourea-promoted cascade aza-Michael-Henry-dehydration reactions: asymmetric preparation of 3-nitro-1,2-dihydroquinolines
作者:Xiaoqian Liu、Yixin Lu
DOI:10.1039/c0ob00223b
日期:——
A cascade aza-Michael-Henry-dehydration reaction catalyzed by quinidine-derived tertiary amine-thiourea catalyst was developed via installation of suitable electron withdrawing groups at the amino function of aniline. This strategy led to a one-step preparation of chiral 3-nitro-1,2-dihydroquinolines in high yields and with up to 90% enantiomeric excesses.