66080-60-2Relevant academic research and scientific papers
Nitrogen-Centered Radical-Mediated Cascade Amidoglycosylation of Glycals
Shang, Wenbin,Zhu, Chunyu,Peng, Fengyuan,Pan, Zhiqiang,Ding, Yuzhen,Xia, Chengfeng
supporting information, p. 1222 - 1227 (2021/03/03)
A nitrogen-centered radical-mediated strategy for preparing 1,2-trans-2-amino-2-deoxyglycosides in one step was established. The cascade amidoglycosylation was initiated by a benzenesulfonimide radical generated from NFSI under the catalytic reduction of TEMPO. The benzenesulfonimide radical was electrophilically added to the glycals, and then the resulting glycosidic radical was converted to oxocarbenium upon oxidation by TEMPO+, which enabled the following anomeric specific glycosylation.
Why Is Direct Glycosylation with N-Acetylglucosamine Donors Such a Poor Reaction and What Can Be Done about It?
Marqvorsen, Mikkel H. S.,Pedersen, Martin J.,Rasmussen, Michelle R.,Kristensen, Steffan K.,Dahl-Lassen, Rasmus,Jensen, Henrik H.
, p. 143 - 156 (2017/04/26)
The monosaccharide N-acetyl-d-glucosamine (GlcNAc) is an abundant building block in naturally occurring oligosaccharides, but its incorporation by chemical glycosylation is challenging since direct reactions are low yielding. This issue, generally agreed upon to be caused by an intermediate 1,2-oxazoline, is often bypassed by introducing extra synthetic steps to avoid the presence of the NHAc functional group during glycosylation. The present paper describes new fundamental mechanistic insights into the inherent challenges of performing direct glycosylation with GlcNAc. These results show that controlling the balance of oxazoline formation and glycosylation is key to achieving acceptable chemical yields. By applying this line of reasoning to direct glycosylation with a traditional thioglycoside donor of GlcNAc, which otherwise affords poor glycosylation yields, one may obtain useful glycosylation results.
Glycosylation with 2-Acetamido-2-deoxyglycosyl Donors at a Low Temperature: Scope of the Non-Oxazoline Method
Arihara, Ryoichi,Kakita, Kosuke,Suzuki, Noritoshi,Nakamura, Seiichi,Hashimoto, Shunichi
, p. 4259 - 4277 (2015/05/13)
A direct construction of 1,2-trans-β-linked 2-acetamido-2-deoxyglycosides was investigated. The 3,4,6-tri-O-benzyl- and 3,4,6-tri-O-acetyl-protected glycosyl diethyl phosphites and 4,6-O-benzylidene-protected galactosyl diethyl phosphite each reacted with
Direct chemical glycosylation with pentenyl- and thioglycoside donors of N-acetylglucosamine
Krag, Jonas,Christiansen, Mira S.,Petersen, Jette G.,Jensen, Henrik H.
experimental part, p. 872 - 879 (2010/06/19)
The use of pentenyl and thiophenyl glycosides of N-acetylglucosamine (GlcNAc) as glycosyl donors for the direct preparation of O-glycosides of GlcNAc promoted by N-iodosuccinimide (NIS) and metal triflates in dichloromethane has been investigated. Both glycosyl acceptors 1-octanol and (-)-menthol resulted in good glycosylation yields for both types of donors with pentenyl glycosides being somewhat superior in terms of yield. Carbohydrate-based acceptors were reacted with a benzylated GlcNAc-pentenyl donor but only provided disaccharides in poor to moderate yields. The results show that a variety of metal triflates are capable of acting as an activator for both NIS and the intermediate oxazoline.
Protected glycosides and disaccharides of 2-amino-2-deoxy-D-glucopyranose by ferric chloride-catalyzed coupling.
Kiso,Anderson
, p. 309 - 323 (2007/10/02)
The ferric chloride-catalyzed glycosylation of hydroxy compounds by protected 2-acylamino-2-deoxy-beta-D-glucopyranose 1-acetates is described. In addition to known glycosides from the reaction of alcohols with 2-acetamido-1,3,4,6-tetra-O-acetyl-2-deoxy-beta-D-glucopyranose (3), ally (and other alkyl) beta-glycosides were obtained from the N-benzoyl, N-phenoxyacetyl, N-methoxyacetyl, N-chloroacetyl, and N-phthaloyl congeners of 3. The latter compounds, except for the N-phthaloyl derivative, gave oxazolines in the absence of an alcoholic reactant. Compound 3 and the related N-benzoyl, N-chloroacetyl, N-acetyl-3,4,6-tri-O-benzyl, and N-acetyl-4-O-acetyl-3,6-di-O-benzyl derivatives were coupled to one or more protected sugars to form protected, beta-linked disaccharides. Coupling at the 6-positions of acceptors proceeded smoothly and gave 67-80% yields. For successful coupling at positions 3 and 4, long reaction times and multiple additions of glycosyl donor were required, and yields ranged from 60% to as low as 30%. 1,3,4,6-Tetra-O-acetyl-2-(chloroacetamido)-2-deoxy-beta-D- glucopyranose appeared to be the most reactive glycosyl donor in this series. The reaction of 2-methyl-(3,4,6-tri-O-acetyl-1,2-dideoxy-alpha-D-glucopyrano)[2,1- d]-2-oxazoline (derived from 3) with allyl alcohol was catalyzed by ferric chloride, and oxazolines were detected as intermediates in some of the glycosylations of protected sugars.
