Regio- and stereoselective anomeric esterification of glucopyranose 1,2-diols and a facile preparation of 2-O-acetylated glucopyranosyl trichloroacetimidates from the corresponding 1,2-diols
摘要:
A highly regio- and stereoselective anomeric esterification of 3-O-allyl (or benzyl, or benzoyl)-4,6-O-isopropylidene-alpha,beta-D-glucopyranose with acetyl chloride, or allyl chloroformate, or ethyl chloroformate gave the corresponding 2-OH, 1-beta-acetates or -carbonates in excellent yields. The 2-OH, 1-beta-acetates were readily converted to the corresponding 2-O-acetylated glucopyranosyl trichloroacetimidates by reaction with trichloroacetonitrile via base promoted acetyl migration, while the 2-OH, 1-beta-carbonates were good glycosyl acceptors for the synthesis of (1 -> 2)-linked oligosaccharides. (c) 2007 Elsevier Ltd. All rights reserved.
Regio- and stereoselective anomeric esterification of glucopyranose 1,2-diols and a facile preparation of 2-O-acetylated glucopyranosyl trichloroacetimidates from the corresponding 1,2-diols
作者:Jianjun Zhang、Xiaomei Liang、Daoquan Wang、Fanzuo Kong
DOI:10.1016/j.carres.2007.01.010
日期:2007.5
A highly regio- and stereoselective anomeric esterification of 3-O-allyl (or benzyl, or benzoyl)-4,6-O-isopropylidene-alpha,beta-D-glucopyranose with acetyl chloride, or allyl chloroformate, or ethyl chloroformate gave the corresponding 2-OH, 1-beta-acetates or -carbonates in excellent yields. The 2-OH, 1-beta-acetates were readily converted to the corresponding 2-O-acetylated glucopyranosyl trichloroacetimidates by reaction with trichloroacetonitrile via base promoted acetyl migration, while the 2-OH, 1-beta-carbonates were good glycosyl acceptors for the synthesis of (1 -> 2)-linked oligosaccharides. (c) 2007 Elsevier Ltd. All rights reserved.
Practical preparation of 2-azido-2-deoxy-β-d-mannopyranosyl carbonates and their application in the synthesis of oligosaccharides
作者:Jianjun Zhang、Shiqiang Yan、Xiaomei Liang、Jingping Wu、Daoquan Wang、Fanzuo Kong
DOI:10.1016/j.carres.2007.09.001
日期:2007.12
1-O-Allyloxycarbonyl (or ethyloxycarbonyl)-2-azido-2-deoxy-3-O-benzyl (or allyl, or benzoyl)-4,6-O-isopropylidene-beta-d-mannopyranose derivatives were prepared from the corresponding 2-hydroxy-beta-d-glucopyranosyl carbonates in high yields via triflation of the 2-hydroxyl group and subsequent SN2 displacement with azide ion. An N-acetyl-mannosamine-containing trisaccharide, a fragment of the putative