核磁共振技术测定联萘酚的对映体纯度

手性联萘酚((±)-BINOL)制备是国内高校常开设的一个实验,其产品的对映体纯度测试是实验的重要一环。以2-甲酰基苯硼酸和(S)-(?)-1-苯乙胺的混合物作为手性试剂与联萘酚发生Bull-James Assembly反应,以此设计了核磁共振氢谱(¹H NMR)测定联萘酚对映体纯度的实验。实验结果表明,通过反应生成的对映体混合物的核磁信号,能准确地计算出(±)-BINOL的对映体纯度。以选定的苯环氢核信号计算出的(R)-BINOL含量与理论ee值有着良好的线性关系(R²=0.9999)。此实验方法能够快速完成大量学生样品的测量,同时大大减少实验废液的产生量。学生通过此实验可对核磁共振技术有更进一步的了解。

Determination of Enantiomeric Purity of Binaphthol by NMR Method

The preparation of chiral binaphthol is a common experiment in colleges and universities,and the determination of enantiomeric purity is an important part of the experiment.The Bull-James Assembly between binaphthol and a mixture of 2-formylphenylboronic acid and(S)-(?)-1-phenylethylamine as chiral reagent was observed.Based on this,an experiment was designed to determine the enantiomer purity of binaphthol via ¹H NMR.The results show that the enantiomer purity of(±)-BINOL can be accurately calculated from the NMR signals of the enantiomer mixture generated by the reaction.There is a good linear relationship(R²=0.9999)between the(R)-BINOL ratio calculated from the selected proton signal and the given ee value.This method can quickly complete the measurement of a large number of student samples,and produce a small amount of waste liquid.Students can have a further understanding of NMR technology through this experiment.