Silica-Catalysed and Highly Stereoselective Convergent and Nonconvergent Rearrangements of Menthone Enol Acetate Epoxides: Easy Access to the Four α-Hydroxymenthone Stereoisomers
作者:Sylvain Tranchimand、Bruno Faure、Jean-Valère Naubron、Véronique Alphand、Alain Archelas、Gilles Iacazio
DOI:10.1002/ejoc.201200414
日期:2012.8
to the biocatalytic access of structurally useful α-hydroxy ketones, we made the unexpected observation that epoxy enol acetates derived from (+)- and (–)-menthone stereoselectively rearranged on exposure to silica through a diastereoselective process, providing easy access to the complete set of α-hydroxymenthone stereoisomers. The absolute configurations of the four stereoisomers were unambiguously
在一个致力于生物催化获取结构上有用的 α-羟基酮的项目中,我们意外地观察到,衍生自 (+)- 和 (-)-薄荷酮的环氧烯醇乙酸酯通过非对映选择性过程暴露于二氧化硅后立体选择性重排,提供了简单的获取完整的 α-羟基薄荷酮立体异构体。通过 IR-VCD 和 X 射线衍射明确确定了四种立体异构体的绝对构型,从而澄清了一些文献差异。四种立体异构体中的两种也可以通过对映会聚过程获得,从而避免了此类非对映选择性反应固有的 50% 产率限制。还描述了允许极快反应 (< 2 h) 的无溶剂版本。最后,