Nucleofuge Generating Glycosidations by the Remote Activation of Hydroxybenzotriazolyl Glycosides
作者:Mahesh Neralkar、Bijoyananda Mishra、Srinivas Hotha
DOI:10.1021/acs.joc.7b02027
日期:2017.11.3
by the extrusion of the oxocarbenium ion that was attacked by the glycosyl acceptor. Further, equilibration of the zwitterionic benzotriazolyl species makes the leaving group noncompetitive and generates the nucleofuge that has been reconverted to the glycosyl donor. The reaction is mild, high yielding, fast and suitable for donors containing both C2-ethers and C2-esters as well. The regenerative-donor
羟基苯并三唑因其增加的反应性而通常用于肽化学中,以减少外消旋作用。在本文中,鉴定出非常稳定的羟基苯并三唑基葡糖苷可以进行糖苷化。假设该反应通过Tf 2进行远程激活在HOBt的N3位点为O,接着是被糖基受体攻击的氧碳鎓离子的挤出。此外,两性离子苯并三唑基物质的平衡使离去基团失去竞争性,并产生已被重新转化为糖基供体的核沉子。该反应温和,高产率,快速并且适合于同时含有C2-醚和C2-酯的供体。再生供体糖苷化策略是有前途的,因为它使我们能够再生糖基供体以供进一步利用。通过成功合成HIV1-gp120复合物的支链五聚甘露聚糖核心,证明了该方法在寡糖合成中的实用性。