A robust synthetic route from l-hydroxyproline (l-Hyp) to phosphines has established an expandable library of six chiral aminophosphines, which were then applied to the phosphine-catalyzed [4 + 2] allene–imine annulation. The enantioinduction in the annulations—induced by a purely steric effect—were moderate (up to 57% ee). A switch of the reaction site from the γ- to the β′-carbon atom of the allenoate
从
1-羟基脯氨酸(1- Hyp)到膦的稳健合成路线建立了六个手性
氨基膦的可扩展文库,然后将其应用于膦催化的[4 + 2]
丙二烯亚胺环化反应。由纯空间效应引起的环空中的对映体诱导是中等的(最高ee为57%)。在使用空间需求的手性膦进行的环合过程中,观察到了反应部位从
脲基酸酯的γ-碳原子转换为β'-碳原子。