A facile synthesis of sialylated oligolactosamine glycans from lactose via the Lafont intermediate
作者:Peng Peng、Han Liu、Jianzhi Gong、John M. Nicholls、Xuechen Li
DOI:10.1039/c4sc01013b
日期:——
The 2-aminophosphonium iodide lactosamine glycoside (Lafont intermediate) readily obtained from lactose has been previously shown not to be amenable to derivatization for oligosaccharide synthesis, but has now been successfully converted via the salicylaldehyde imine into suitably protected lactosamine building blocks (13–16) for glycosylation. The titled strategy has enabled us to rapidly synthesize
A new sulfonium-salt-based iodine(I) reagent system for the vicinal functionalisation of glycals and enol ethers has been developed. The unprecedented iodine(I) complex, Me3SI(OAc)2, generated in situ from Me3SI and PhI(OAc)2, effectively promoted the one-pot iodocarboxylation using carboxylic acids, and iodoazidation using NaN3 or TMSN3 (trimethylsilyl azide). The scope and generality of the new reagent
Four neoglycolipids having 2-amino-2-deoxy-D-glucose or D-galactose moieties linked to the lipidic parr by a glucitol or a mannitol spacer-arm have been synthesized. The key step of the synthetic strategy was the regiospecific or regioselective beta -glycosylation of partially protected glucitol or mannitol accepters by either 3,4,6-tri-O-acetyl-2-deoxy-2-iodo-alpha -D-mannopyranosyl azide or 2,3,4,6-tetra-O-benzoyl-alpha -D-galactopyranosyl trichloroacetimidate donors. (C) 2001 Elsevier Science Ltd. All rights reserved.
Peter, Martin G.; Boldt, Peter-C.; Petersen, Stefan, Liebigs Annalen der Chemie, 1992, # 12, p. 1275 - 1280
作者:Peter, Martin G.、Boldt, Peter-C.、Petersen, Stefan
DOI:——
日期:——
Syntheses of l-glucosamine donors for 1,2-trans-glycosylation reactions
作者:Dominique Lafont、Paul Boullanger
DOI:10.1016/j.tetasy.2006.12.011
日期:2006.12
Two new L-glucosarnine donors, that is pent-4-enyl 3,4,6-tri-O-acetyl-2-allyloxycarbonylamino-2-deoxy-beta-L-glucopyranoside 16 and ethyl 3,4,6-tri-O-acetyl-2-allyloxycarbonylamino-2-deoxy-l-thio-beta-L-glucopyranoside 21 were prepared in 12 steps from L-arabinose. The reaction pathway uses 3,4,6-tri-O-acetyl-L-glucal 5, and then 3,4,6-tri-O-acetyl-2-deoxy-2-iodO-alpha-L-mannopyranosyl azide 8 as intermediates. The latter, together with donors 16 and 21, were used for preparing L-glucosamine neoglycolipids. (c) 2007 Elsevier Ltd. All rights reserved.