The Stereoselective Synthesis of 2-Aryl-2-hydroxybutanoic Acid via Menthyl Chiral Auxiliaries
作者:Ji-Ming Xiang、Bao-Lin Li
DOI:10.1002/hlca.201000024
日期:2010.10
In the presence of titanium(IV) tetraethoxide ((EtO)4Ti), menthyl arylglyoxylates are prepared by transesterification of ethyl arylglyoxylates and natural (−)‐(1R,2S,5R)‐menthol. Using menthyl as a chiral auxiliary, the corresponding novel (R)‐menthyl 2‐aryl‐2‐hydroxybutanoates are synthesized by the addition of Et2Zn with menthyl arylglyoxylates. The structures of the products are characterized by
在四乙氧基钛(IV)((EtO)4 Ti)存在下,芳基乙醛酸薄荷酯是通过芳基乙醛酸乙酯与天然(-)-(1 R,2 S,5 R)-薄荷醇进行酯交换反应制得的。使用薄荷基作为手性助剂,通过添加Et 2 Zn与薄荷基芳基乙醛酸酯合成相应的新型(R)-薄荷基2-芳基-2-羟基丁酸酯。产品的结构以IR和1 H‐和13为特征C-NMR光谱,质谱和元素分析。通过HPLC分析非对映选择性。加成反应以良好的收率和高的非对映异构体过量(高达95%)完成,并且在水解后,获得的(R)-2-芳基-2-羟基丁酸具有很高的光学纯度。