Department of Chemistry and Biochemistry, University of Missouri─St. Louis, One University Boulevard, St. Louis, Missouri 63121, United States.
Department of Chemistry, Saint Louis University, 3501 Laclede Avenue, St. Louis, Missouri 63103, United States.
J Org Chem. 2022 Jan 7;87(1):271-280. doi: 10.1021/acs.joc.1c02351. Epub 2021 Dec 20.
A method for direct, highly stereoselective synthesis of glycans containing β-linked d-mannosaminuronic acid (ManNAcA) residues is reported herein, among which is the capsular polysaccharide of type 8. Previous chemical syntheses of this glycan relied on indirect methods comprising glucosylation followed by a multistep epimerization and oxidation sequence. The high β-stereocontrol with direct glycosidation of 3--picoloylated ManNAcA donors was achieved using the H-bond-mediated aglycone delivery (HAD) reaction. A method to achieve complete α-ManNAcA stereoselectivity with 3--benzoylated donors is also reported.
本文报道了一种直接、高度立体选择性合成含有β-连接的 D-甘露糖胺醛酸（ManNAcA）残基的聚糖的方法，其中包括 8 型荚膜多糖。以前对这种聚糖的化学合成依赖于间接方法，包括葡萄糖基化，然后是多步差向异构化和氧化序列。通过使用氢键介导的糖苷配基传递（HAD）反应，实现了 3--对甲酰化 ManNAcA 供体的高β-立体控制的直接糖苷化。还报道了一种用 3--苯甲酰化供体实现完全α-ManNAcA 立体选择性的方法。
