An alkaloid-mediated desymmetrization of meso-anhydrides via a nucleophilic ring opening with benzyl alcohol and its application in the synthesis of highly enantiomerically enriched β-amino acids
作者:Carsten Bolm、Ingo Schiffers、Iuliana Atodiresei、Christian P.R. Hackenberger
DOI:10.1016/s0957-4166(03)00579-2
日期:2003.11
permits the isolation of the products in analytically pure form and the recovery of the alkaloids almost quantitatively. These hemiesters can be converted to N-protected β-amino esters by means of Curtius degradation of the corresponding acyl azides. Subsequent cleavage of both protecting groups by a single reaction step leads to the free β-amino acids in excellent yields. The efficiency of this procedure
描述了在苄醇存在下金鸡纳生物碱介导的前手性环酐的打开,导致旋光性半酯。通过使用奎宁或奎尼丁作为导向添加剂,将结构多样的酸酐转化为相应的苄基单酯,其中对映异构体的ee最高可达99%。一个简单的水后处理方案可以分离出分析纯形式的产物,并几乎定量地回收生物碱。这些半个学期可以转换为N-通过相应的酰基叠氮化物的库尔蒂斯降解来保护-β-氨基酯。随后通过单个反应步骤裂解两个保护基团以优异的产率得到游离的β-氨基酸。通过短时不对称合成杀真菌剂顺-喷他汀来证明该方法的效率,所述顺式-喷他霉素递送氨基酸的对映体过量> 99.7%。