2,3-Epoxy sulfides and 2,3-epoxy amines, prepared in an optically active form via the Sharpless asymmetric epoxidation, both undergo a Lewis acid induced rearrangement to give the corresponding thiiranium and aziridinium ions respectively. These reactive intermediates, generated in situ, react efficiently with a variety of nucleophiles such as silylated aromatic heterocycles, amides, and amines, including amino acid derivatives. Imines can be used as synthetic equivalents of primary amine nucleophiles, which effectively allows selective monoalkylation with a reactive thiiranium ion intermediate. Applications of this new methodology, and mechanistic studies are also discussed.
2,3-环
氧硫化物和2,3-环
氧胺通过Sharpless不对称环
氧化制备成光学活性形式,均在
路易斯酸的诱导下发生重排,分别生成相应的
硫铵离子和
叠氮离子。这些在原位生成的反应
中间体与各种亲核试剂有效反应,如
硅化的芳香杂环、
酰胺和胺,包括
氨基酸衍
生物。
亚胺可以用作一级胺亲核试剂的合成等价物,这有效地实现了与反应活性
硫铵离子
中间体的选择性单烷基化。还讨论了这一新方法的应用及其机理研究。