Chemoselective glycosylations (part 1): Differences in size of anomeric leaving groups can be exploited in chemoselective glycosylations
作者:Geert-Jan Boons、Richard Geurtsen、Duncan Holmes
DOI:10.1016/0040-4039(95)01222-4
日期:1995.8
We have developed a novel chemoselectiveglycosylation strategy. This glycosylation strategy is based on the fact that the glycosyl reactivity of an anomeric thiol groupcan be control by the bulkiness of this group whereby we have produced a new range of differentially reactive coupling substrates. The new approach will enable complex oligosaccharides of biological importance to be prepared in a highly
Chemoselective Glycosylation Strategy for the Convergent Assembly of Phytoalexin-Elicitor Active Oligosaccharides and Their Photoreactive Derivatives
作者:Richard Geurtsen、François Côté,、Michael G. Hahn、Geert-Jan Boons
DOI:10.1021/jo990836o
日期:1999.10.1
A highly convergent route for the synthesis of branched glucosides having phytoalexin-elicitor activity has been developed. The readily available building blocks 2, 3, and 6 were used for the assembly of a core trisaccharide in two chemo- and regioselective glycosylations. Compound 7 was converted into the artificial spacer-containing glycosyl acceptor 9. Regioselective condensation of fragment 7 with 9 Zed to the formation of fully protected hexasaccharide 14. Deprotection of hexasaccharide 14 followed by the reaction with 4-azidosalicylate gave compound 1b. It was established that compound Ib is a photoreactive compound. Reaction time and conditions were established for photolysis of compound 1b and labeling with radioactive iodine. A soybean root binding site for an elicitor-active hepta-beta-glucoside bound compound 1b with the same affinity as the underivatized hepta-beta-glucoside.