A Blockwise Approach to the Synthesis of (1→2)‐Linked Oligosac­char­ides Corresponding to Fragments of the Acid‐Stable β‐Mannan from the Candida albicans Cell Wall

Abstract

AbstractOligomannosides comprising short β‐(1→2)‐oligomannosyl blocks attached through a glycoside bond to an α‐(1→2)‐linked oligomannoside are a constituent of side chains of the mannan from the Candida cell wall. This type of oligomannoside is known as an acid‐stable β‐mannan and corresponds to the antigenic factor 6. In this communication, we report a convergent blockwise synthesis of four spacer‐armed oligomannosides of this type including from 1 to 4 β‐mannosyl and 2–3 α‐mannosyl residues. β‐(1→2)‐Oligomannosyl thioglycosides and sulfoxides containing up to four mannose units were employed for introduction of β‐oligomannoside sequences. The efficiency of β‐mannosylation with mono‐ and oligomannoside donors was shown to depend more on the structure of the reaction partners than on the applied activation protocol. The oligomannosides obtained will be used to prepare various molecular tools for investigation of the Candida cell wall.