Efficient Remote Axial-to-Central Chirality Transfer in Enantioselective SmI<sub>2</sub>-Mediated Reductive Coupling of Aldehydes with Crotonates of Atropisomeric 1-Naphthamides
作者:Yan Zhang、Yongqiang Wang、Wei-Min Dai
DOI:10.1021/jo0526486
日期:2006.3.1
different 2-substituted 8-methoxy-1-naphthamides. The enantiomers of atropisomeric 8-methoxy-1-naphthamides were prepared through a chemical resolution process, and their absolute stereochemistry was determined by X-ray crystal structural analysis. It was found that the linkage between crotonate and the C2 position of 8-methoxy-1-naphthamides remarkably influenced the efficiency of remote chirality transfer
在SmI 2介导的醛与具有不同的2-取代的8-甲氧基-1-萘酰胺的巴豆酸酯的还原偶联中,已经研究了通过远程酰胺构象控制对映选择性的方法。通过化学拆分方法制备对映异构体8-对甲氧基-1-萘酰胺的对映异构体,并通过X射线晶体结构分析确定其绝对立体化学。发现巴豆酸酯和8-甲氧基-1-萘酰胺的C2位之间的键合显着影响源自酰胺构象的远程手性转移的效率。在所检查的四种巴豆酸酯中,一种由2-羟基-8-甲氧基-1-萘酰胺衍生的戊烯酸酯与戊醛反应,以使顺式的ee最高,> 99%-γ-丁内酯,合并产率为90%,顺/反比为90:10。我们开发了一种在温和条件下通过C8氧将手性巴豆酸酯连接到Rink酰胺树脂上的新程序,并在固相反应中获得了相同水平的极远的轴向向中心手性转移。