A facile stereoselective synthesis of α-glycosyl ureas
摘要:
alpha-Glycosyl ureas can be synthesised directly from tetra-O-benzyl glycosyl azides and isocyanates, using a one-pot procedure that is simple and general in scope. The benzyl protecting groups are easily removed from the urea products by catalytic hydrogenation. The synthesised alpha-glycosyl ureas represent a new class of neo-glycoconjugates with the potential of being resistant towards carbohydrate processing enzymes. (c) 2006 Elsevier Ltd. All rights reserved.
Traceless Staudinger Ligation of Glycosyl Azides with Triaryl Phosphines: Stereoselective Synthesis of Glycosyl Amides
作者:Aldo Bianchi、Anna Bernardi
DOI:10.1021/jo060409s
日期:2006.6.1
α-Glycosyl amides can be synthesized from the corresponding O-benzyl-α-glycosyl azides using a tracelessStaudingerligation with diphenylphosphanyl-phenyl esters 4. All the phosphines employed and their phenol precursors are stable to air at 4 °C for months. Fast intramolecular trapping of the reduction intermediates results in the direct formation of the amide link, which, in turn, prevents epimerisation
Gold(III)-Catalyzed Glycosylation using Phenylpropiolate Glycosides: Phenylpropiolic Acid, An Easily Separable and Reusable Leaving Group
作者:Mukta Shaw、Rima Thakur、Amit Kumar
DOI:10.1021/acs.joc.8b02422
日期:2019.1.18
synthesized benchtop stable phenylpropiolate glycosyl (PPG) donors. Gold(III)-catalyzed activation of PPGs proceeds well with various carbohydrate and noncarbohydrate-based glycosyl acceptors and leads to their corresponding O/N-glycosides in good to excellent yields with regeneration of reusable and easily separable phenylpropiolic acid. Differentially protected PPGs reacted well under the optimized reaction
The direct stereoselective conversion of various alcohols and hexopyranoses into the corresponding alkyl azides and glycosyl azides, respectively, is efficiently accomplished by using bis(p-nitrophenyl) phosphorazidate and DBU.
Stereoselective synthesis of glycosyl azides from anomeric hydroxides via protecting group manipulations
作者:Sourav Nayak、Somnath Yadav
DOI:10.1016/j.carres.2023.108739
日期:2023.1
report the direct conversion of anomeric hydroxides to glycosyl azides in one step using diphenylphosphoryl azide. Protecting group manipulations on the hexose sugars have enabled the stereoselectivesynthesis of either the α-glycosyl azides or the β-anomeric azides in moderate to very good yields. The reaction has also been successfully used to enable the synthesis of β-2-deoxy-2-aminoglucosyl azides
Selective synthesis of anomeric α-glycosyl acetamides via intramolecular Staudinger ligation of the α-azides
作者:Aldo Bianchi、Anna Bernardi
DOI:10.1016/j.tetlet.2003.12.159
日期:2004.3
alpha-Glycosyl azides can be transformed into the corresponding alpha-glycosyl acetamides with complete retention of configuration via reduction-acylation (Staudinger ligation) reactions using specifically functionalized phosphines. The of alpha-acetamides of per-O-benzylated-fucose, per-O-benzylated-glucose and per-O-benzylated-galactose were selectively synthesized by this process. (C) 2004 Elsevier Ltd. All rights reserved.