Direct Synthesis of 2,6‐Dideoxy‐β‐glycosides and β‐Rhamnosides with a Stereodirecting 2‐(Diphenylphosphinoyl)acetyl Group

Autor: Xianglai Liu, Yetong Lin, Wenyi Peng, Zhaolun Zhang, Longwei Gao, Yueer Zhou, Zhe Song, Yingjie Wang, Peng Xu, Biao Yu, Haopeng Sun, Weijia Xie, Wei Li
Rok vydání: 2022
Předmět:
Zdroj: Angewandte Chemie. 134
ISSN: 1521-3757
0044-8249
Popis: Anomeric stereocontrol is usually one of the major issues in the synthesis of complex carbohydrates, particularly those involving β-configured 2,6-dideoxyglycoside and d/l-rhamnoside moieties. Herein, we report that 2-(diphenylphosphinoyl)acetyl is highly effective as a remote stereodirecting group in the direct synthesis of these challenging β-glycosides under mild conditions. A deoxy-trisaccharide as a mimic of the sugar chain of landomycin E was prepared stereospecifically in high yield. The synthetic potential was also highlighted in the synthesis of Citrobacter freundii O-antigens composed of a [→4)-α-d-Manp-(1→3)-β-d-Rhap(1→4)-β-d-Rhap-(1→] repeating unit, wherein the convergent assembly up to a nonasaccharide was realized with a strongly β-directing trisaccharide donor. Variable-temperature NMR studies indicate the presence of intermolecular H-bonding between the donor and the bulky acceptor as direct spectral evidence in support of the concept of hydrogen-bond-mediated aglycone delivery.
Databáze: OpenAIRE
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