Synthesis 2024; 56(03): 487-495
DOI: 10.1055/s-0043-1763649
paper

Convenient Synthesis of the Branched Hexasaccharide Repeating Unit of the Cell Wall O-Antigen of Escherichia coli O80 Strain

Samim Sahaji
,
Anup Kumar Misra

S.S. thanks University Grants Commission: Maulana Azad National Fellowship (UGC-MANF), India for a senior research fellowship. This work was partly supported by the Science and Engineering Research Board (SERB), New Delhi (Project No. CRG/2019/000352 dated 23.01.2020) (A.K.M.).


Abstract

Chemical synthesis of a branched hexasaccharide corresponding to the cell wall O-antigen of Escherichia coli (E. coli) O80 strain has been achieved in very good yield with satisfactory stereochemical outcome around the glycosidic linkages by applying a regio- and stereoselective [4+2] block glycosylation strategy. The tetrasaccharide diol derivative was synthesized from suitably functionalized monosaccharide intermediates using sequential stereoselective glycosylations and the disaccharide thioglycoside donor was obtained applying a regio- and stereoselective orthogonal armed-disarmed glycosylation strategy using protected thioglycoside derivatives. A late-stage TEMPO and bis(acetoxy)iodobenzene (BAIB) mediated regioselective oxidation of the primary hydroxyl group of the protected hexasaccharide derivative to the carboxylic acid was achieved leaving secondary hydroxyl groups unaffected.

Supporting Information



Publication History

Received: 11 October 2023

Accepted after revision: 16 November 2023

Article published online:
11 December 2023

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