手性高烯丙基胺的合成及表征——一个微量不对称合成教学实验

Diastereoselective Synthesis and Characterization of Homoallylic N-tert-Butanesulfinyl Amines:An Asymmetric Synthesis Experiment for the Undergraduate Organic Laboratory

描述了一个以立体化学中非对映选择性为知识重点,以无水无氧操作为操作重点的微量不对称合成实验。(R)-N-叔丁基亚磺酰亚胺在无水无氧环境中,经过锌参与的烯丙基化,在不同的溶剂、添加剂条件下以不同的选择性得到了一对非对映异构体,以较高的产率得到终产物。烷基化反应产物的非对映体比率(dr)通过1H与19F NMR以及手性HPLC确定。总体来说,这一实验所用试剂易得,反应条件温和,速率快,产率高;学生在学习无水无氧操作(Schlenk技术)的同时,还能够熟悉立体化学的基本概念,了解如何通过调节反应溶剂和添加剂实现立体化学结果的逆转,并掌握使用手性HPLC和NMR确定光学活性物质的dr值的方法。

An asymmetric synthetic experiment that encompasses the knowledge of stereoselectivity and the practice of Schlenk techniques is described.In this experiment,Zn-mediated allylation of an(R)-N-tert-butanesulfinyl imine is performed using different conditions of solvent and additive.The reactions give both diastereomers in good yields and in various diastereomeric ratio(dr),which is determined by 1H,19F NMR spectroscopy and chiral HPLC.Overall,this experiment can be carried out with readily accessible reagents under mild conditions,and be finished within limited laboratory time.Moreover,it enables students to learn the basics of Schlenk techniques,the differences between enantiomers and diastereomers,how a reversal of stereochemical outcome is realized by tuning the reaction solvent and additive,and the determination of dr regarding optical compounds using HPLC and NMR spectroscopy.