Side Chain Conformation and Its Influence on Glycosylation Selectivity in Hexo- and Higher Carbon Furanosides
作者:Sameera Siyabalapitiya Arachchige、David Crich
DOI:10.1021/acs.joc.1c02374
日期:2022.1.7
arising from participation by the various benzyl ethers. The increased importance of ether participation in the furanoside series compared to the pyranosides is discussed in terms of the reduced stabilization afforded to furanosyl oxocarbenium ions by covalent triflate formation. The stereoselectivities of the four donors are discussed on the basis of the benzyl ether participation model.
我们描述了一系列四种 6-deoxy-2,3,5-tri- O -benzyl hexofuranosyl供体的合成和侧链构象分析,其中d -gluco 、l -ido、d -altro 和l-半乳糖配置。这些化合物的环外键的构象取决于侧链与环的连接点和两个侧翼中心的相对构型,并且可以在此基础上类似于庚吡喃糖类似物进行预测。活化供体的变温核磁共振 (VT NMR) 光谱揭示了复杂的、依赖于构型的中间体混合物,我们将其解释为由各种苄醚参与产生的稠合和桥接的氧鎓离子。与吡喃糖苷相比,醚参与呋喃糖苷系列的重要性增加,讨论了通过共价三氟甲磺酸酯形成对呋喃糖基氧碳鎓离子提供的稳定性降低。