Total Synthesis of Tiacumicin B: Study of the Challenging β‐Selective Glycosylations**
作者:Cédric Tresse、Marc François‐Heude、Vincent Servajean、Rubal Ravinder、Clémence Lesieur、Lucie Geiben、Louis Jeanne‐Julien、Vincent Steinmetz、Pascal Retailleau、Emmanuel Roulland、Jean‐Marie Beau、Stéphanie Norsikian
DOI:10.1002/chem.202005102
日期:2021.3.17
We give a full account of the total synthesis of tiacumicin B (Tcn‐B), a natural glycosylated macrolide with remarkable antibiotic properties. Our strategy is based on our experience with the synthesis of the tiacumicin B aglycone and on unique 1,2‐cis‐glycosylation steps. We used sulfoxide anomeric leaving‐groups in combination with a remote 3‐O‐picoloyl group on the donors that allowed highly β‐selective
我们全面介绍了头孢菌素B(Tcn-B)的总合成,头孢菌素B(Tcn-B)是一种具有显着抗生素特性的天然糖基化大环内酯。我们的策略是基于我们合成头孢菌素B糖苷配基的经验以及独特的1,2-顺式糖基化步骤。我们使用亚砜异头离去基团结合有远程3- Ô供体上的吡啶甲酸基团允许依赖于H键介导的糖苷配基的高度β-选择性鼠李糖基化和noviosylation。鼠李糖基化的C1-C3片段通过Suzuki-Miyaura交叉偶联固定在C4-C19糖苷配基片段上。环大小选择性的Shiina宏观内酯化提供了一个半糖基化糖苷配基,该糖苷配基直接参与了noviolysation步骤,具有几乎全部的β选择性。最后,设计了一种新颖的脱保护方法,用于去除苯酚上的2-萘基甲基醚,并有效去除所有保护基团,从而提供了合成的tiacumicin B.