A U-Turn in the Asymmetric Appel Reaction: Stereospecific Reduction of Diastereomerically Enriched Alkoxyphosphonium Salts Allows the Asymmetric Synthesis of P-Stereogenic Phosphanes and Phosphane Boranes
作者:Kamalraj V. Rajendran、Jaya S. Kudavalli、Katherine S. Dunne、Declan G. Gilheany
DOI:10.1002/ejoc.201200285
日期:2012.5
recovered unchanged. The simple and efficient protocol significantly expands the scope of our asymmetric Appel process. The crucial step in the preparation involves stereospecific reduction of intermediate diastereomeric alkoxyphosphonium salts, which are obtained in the reaction of phosphane, hexachloroacetone, and menthol. Thereby, reaction with LiAlH4 or NaBH4 gives the corresponding phosphanes or phosphane
在不对称 Appel 条件下,从相应的外消旋膦以优异的产率开发了对映体富集的 P-立体膦和膦硼烷的有效一锅合成。手性助剂(薄荷醇)也可以原样回收。简单高效的协议显着扩展了我们的非对称 Appel 流程的范围。制备中的关键步骤涉及中间体非对映异构烷氧基鏻盐的立体定向还原,这些盐是在膦、六氯丙酮和薄荷醇的反应中获得的。因此,与 LiAlH4 或 NaBH4 反应分别得到相应的膦或膦硼烷。