Stereoretentive Intramolecular Glycosyl Cross-Coupling: Development, Scope, and Kinetic Isotope Effect Study
作者:Duk Yi、Feng Zhu、Maciej A. Walczak
DOI:10.1021/acs.orglett.8b01927
日期:2018.8.3
A series of cyclic C-glycosides were synthesized using the palladium-catalyzed stereoretentive intramolecular glycosylation of aryl iodides by employing a bulkyphosphine ligand. A variety of functional groups are tolerated in the reaction, and enantioenriched anomeric nucleophiles could be coupled without erosion of optical purity. This study offers a unified method to access both cis- and trans-fused
通过使用庞大的膦配体,使用钯催化的芳基碘的立体保留分子内糖基化合成了一系列环状C-糖苷。反应中允许使用多种官能团,并且对映体富集的异头亲核试剂可以在不损害光学纯度的情况下偶联。这项研究提供了一种通过利用 Stille 反应的立体保持性来访问顺式和反式稠环的统一方法。此外,分子间和分子内交叉偶联的竞争实验显示,二次 KIE 分别为 1.43 和 0.81,表明在过渡态存在截然不同的空间拥塞。
Observation of .alpha.-silyl carbanions in the metalation of 3,4,6-tri-O-(tert-butyldimethylsilyl)-D-glucal
作者:Richard W. Friesen、Claudio F. Sturino、Anand K. Daljeet、Aleksandra Kolaczewska