Strained Enamines as Versatile Intermediates for Stereocontrolled Construction of Nitrogen Heterocycles
作者:Gang Chen、Mikio Sasaki、Xinghan Li、Andrei K. Yudin
DOI:10.1021/jo0607921
日期:2006.8.1
and [4.1.0] bicyclic enamines have been prepared by intramolecular oxidative cycloamination of aziridine-containing olefins. This process is initiated by N-bromosuccinimide followed by base-mediated elimination of HBr to afford highly strained exo-bicyclic enamines. In addition, intramolecular aziridine addition to aldehyde functionality was found to afford the [3.1.0] and [4.1.0] bicyclic hemiaminals
该贡献评估了将构象约束施加于氮丙啶衍生的烯胺上的分子的合成效用。合成上通用的[3.1.0]和[4.1.0]双环烯胺是通过分子内含氮丙啶的烯烃的氧化环胺化反应制备的。此过程由N启动-溴代琥珀酰亚胺,然后通过碱介导的消除HBr,得到高度紧张的外双环烯胺。另外,发现分子内氮丙啶加成醛官能团可得到[3.1.0]和[4.1.0]双环缩醛。这些路线突显了无需氮保护/脱保护步骤就可对含氮丙啶的前体进行化学选择性氧化转化的可能性。所得产物提供了直接合成进入大范围的含吡咯烷和哌啶的杂环的位置,这些杂环通过氮丙啶开环而朝向随后的转化定位。