The installation of the 2-furyl ring at the anomeric carbon of 2,3,4,6-tetra-O-benzyl-D-glucopyranose and 2,3.5,6-di-O-isopropylidene-D-mannofuranose is carried out either by addition of 2-lithiofuran to the corresponding lactones either by direct C-glycosidation of the O-acetyl derivatives with furan; the resultant 2-furyl C-glycosides are converted to carboxylic acids by the oxidative cleavage of the furan nucleous.
Dye-Sensitized Photooxygenation of 2,5-Bis(glycosyl)furans
作者:Flavio Cermola、Maria R. Iesce、Anna Astarita、Monica Passananti
DOI:10.2174/157017811795685027
日期:2011.6.1
The dye-sensitizedphotooxygenation of 2,5-bis(glycosyl)furans followed by warming up to r.t. provides 1,1- linked disaccharides separated by a functionalized spacer. Asymmetrical disubstituted glycosyl furans give the corresponding Bayer-Villiger type-rearranged products in a molar ratio depending on the sugars and the protecting groups. The migratory aptitudes have been rationalized by both theoretical
2,5-双(糖基)呋喃的染料敏化光氧合,然后预热至rt,可提供被功能化间隔基分隔的1,1-连接二糖。不对称的二取代的糖基呋喃根据糖和保护基团的摩尔比得到相应的Bayer-Villiger型重排产物。理论计算和实验数据都使移民的才能得到了合理化。获得的1,1-二糖是结构上与Sialyl Lewis X的某些模拟物相关的新糖衍生物。
Synthesis of C-Glycosides from S-Glycosyl Phosphorothioates
作者:W. Kudelsk
DOI:10.1515/znb-2002-0217
日期:2002.2.1
Treatment of O-benzyl protected S-glucosyl phosphorothioates with 1,3,5 trimethoxybenzene in the presence of iodine or borontrifluorideetherate led to appropriate aryl C-β-Dglucosides. The reaction of O-benzyl and O-acetyl-protected phosphorothioates of monosaccharides with allyltrimethylsilane, usingborontrifluorideetherate as activator, gave mainly or exclusively, the corresponding 3-(α-D-
Alditols have been obtained in very high yield using an excess of electron-rich furans with respect to the protected sugars. The scope and limitation of the reaction have been explored. (C) 2011 Elsevier Ltd. All rights reserved.
Retention of configuration in the coupling of aluminated heterocycles with glycopyranosyl fluorides
作者:Simon J. F. Macdonald、Wouter B. Huizinga、Thomas C. McKenzie