Synthesis of an O-sulfo LewisX analog as glycolipid antigen
摘要:
The title compound containing dihydroceramide as a ligand for CD1d was accomplished using the mannosyl, glucosaminyl, and fucosyl donors, and a sphinganine analogue, as suitable building blocks. The 2-O-unprotected mannosyl donor was coupled effectively with the sphinganine analog to afford the mannnosyl sphinganine derivative. The coupling of the glucosaminyl donor with the mannnosyl sphinganine acceptor required triflic acid as a promoter and the promoter change to silver triflate led to the undesired glycal production. The reduction of azide group using Zn powder was the key process, in which the amount of acetic acid was restricted to avoid the benzoyl migration and N-trichloroacetyl deprotection. The trisaccharide glycolipid was sulfonated at the 3-position of fucose moiety. (C) 2011 Elsevier Ltd. All rights reserved.
Synthesis of an O-sulfo LewisX analog as glycolipid antigen
作者:Shuhei Ueno、Shigeomi Horito
DOI:10.1016/j.carres.2011.06.027
日期:2011.10
The title compound containing dihydroceramide as a ligand for CD1d was accomplished using the mannosyl, glucosaminyl, and fucosyl donors, and a sphinganine analogue, as suitable building blocks. The 2-O-unprotected mannosyl donor was coupled effectively with the sphinganine analog to afford the mannnosyl sphinganine derivative. The coupling of the glucosaminyl donor with the mannnosyl sphinganine acceptor required triflic acid as a promoter and the promoter change to silver triflate led to the undesired glycal production. The reduction of azide group using Zn powder was the key process, in which the amount of acetic acid was restricted to avoid the benzoyl migration and N-trichloroacetyl deprotection. The trisaccharide glycolipid was sulfonated at the 3-position of fucose moiety. (C) 2011 Elsevier Ltd. All rights reserved.
Stereoselective β‐Mannosylation via Anomeric
<i>O</i>
‐Alkylation with L‐Sugar‐Derived Electrophiles
A total synthesis of the trisaccharide repeat unit of Salmonella serogroup E1 O-antigen is achieved. The key step involved the Cs2CO3-mediated anomericO-alkylation of partially protected D-mannose with an L-fucose-derived C4-triflate to furnish desired β-linked disaccharide in 50 % yield.