Stereospecific synthesis of 1,2-cis-glycosides of 2-amino sugars

Kochetkov, N. K.; Klimov, E. M.; Malysheva, N. N.; Demchenko, Alexei V.

doi:10.1016/0008-6215(93)80050-o

Cited by 18 publications

(7 citation statements)

References 8 publications

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“…Accordingly, coupling of C(2)-hydroxyl group of mannose derivative 18 with C(2)- N -substituted benzylidene donors 5 − 7 provided disaccharides 28 − 30 in good yields (87−97%) and exclusively as the α-isomers (entry 5). With Kochetkov’s C(2)-azido thiocyanate donor, coupling of 18 also afforded the α-isomer as the major product, albeit in lower yield (72%) . When dihydrocholesterol 19 was employed as a nucleophile, the corresponding glycoconjugate 31 was obtained in 85% yield with an 11:1 α:β ratio (entry 6).…”

Section: Resultsmentioning

confidence: 99%

Nickel-Catalyzed Stereoselective Glycosylation with C(2)-N-Substituted Benzylidene d-Glucosamine and Galactosamine Trichloroacetimidates for the Formation of 1,2-cis-2-Amino Glycosides. Applications to the Synthesis of Heparin Disaccharides, GPI Anchor Pseudodisaccharides, and α-GalNAc

Mensah

Nguyen

2010

J. Am. Chem. Soc.

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The 1,2-cis-2-amino glycosides are key components found within a variety of biologically important oligosaccharides and glycopeptides. Although there are remarkable advances in the synthesis of 1,2-cis-2-amino glycosides, disadvantages of the current state-of-the-art methods include limited substrate scope, low yields, long reaction times, and anomeric mixtures. We have developed a novel method for the synthesis of 1,2-cis-2-amino glycosides via nickel-catalyzed α-selective glycosylation with C(2)-N-substituted benzylidene D-glucosamine and galactosamine trichloroacetimidates. These glycosyl donors are capable of coupling to a wide variety of alcohols to provide glycoconjugates in high yields with excellent levels of α-selectivity. Additionally, only a substoichiometric amount of nickel (5-10 mol %) is required for the reaction to occur at 25 °C. The current nickel method relies on the nature of the nickel-ligand complex to control the α-selectivity. The reactive sites of the nucleophiles or the nature of the protecting groups have little effect on the α-selectivity. This methodology has also been successfully applied to both disaccharide donors and acceptors to provide the corresponding oligosaccharides in high yields and α-selectivity. The efficacy of the nickel procedure has been further applied toward the preparation of heparin disaccharides, GPI anchor pseudodisaccharides, and α-GluNAc/GalNAc. Mechanistic studies suggest that the presence of the substituted benzylidene functionality at the C(2)-amino position of glycosyl donors is crucial for the high α-selectivity observed in the coupling products. Additionally, the α-orientation of the C(1)-trichloroacetimidate group on glycosyl donors is necessary for the coupling process to occur.

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Section: Resultsmentioning

confidence: 99%

Nickel-Catalyzed Stereoselective Glycosylation with C(2)-N-Substituted Benzylidene d-Glucosamine and Galactosamine Trichloroacetimidates for the Formation of 1,2-cis-2-Amino Glycosides. Applications to the Synthesis of Heparin Disaccharides, GPI Anchor Pseudodisaccharides, and α-GalNAc

Mensah

Nguyen

2010

J. Am. Chem. Soc.

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“…This approach, developed by Kochetkov et al, provided complete a-stereoselectivity of glycosylation even in dichloromethane, a reaction solvent that does not typically favor a-glycosylations. 164 For example, coupling of thiocyanate 69, obtained from bromide 68, with 6-O-tritylated glycosyl acceptor 70 in the presence of TrClO 4 provided a-linked disaccharide 71 in 81% yield (Scheme 13).…”

Section: From O-sulfonyl Derivativesmentioning

confidence: 99%

Recent trends in the synthesis of O-glycosides of 2-amino-2-deoxysugars

Bongat

Demchenko

2007

Carbohydrate Research

199

110

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“…Potassium 2-mercaptobenzoxazole 29 (KSBox) (0.600 g, 3.17 mmol) and 18-crown-6 (0.67 g, 0.25 mmol) were added to a stirring solution of 3,4,6-tri-O-acetyl-2-azido-2-deoxy-α-Dglucopyranosyl bromide 30 (0.50 g, 1.27 mmol) in dry acetone (10 mL), then the reaction mixture was stirred under argon for 2.5 hours at room temperature. Upon completion, the solid was filtered off and rinsed successively with CH 2 Cl 2 .…”

Section: Synthesis Of Glycosyl Donorsmentioning

confidence: 99%

A study of silver (I) perchlorate as an effective promoter for chemical glycosylation with thioimidates and thioglycosides

Hasty¹,

Ranade²,

Demchenko³

2014

ROC

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It has been previously acknowledged that perchlorate salts may be beneficial for the formation of 1,2-cis glycosides. Here, we demonstrate the effectiveness of silver (I) perchlorate as a powerful promoter of glycosyl thioimidate activation. Improved 1,2-cis selectivity was obtained, compared against that obtained with other silver (I) salts, including commonly-used triflate. The use of a combination of silver (I) perchlorate and methyl sulfenyl bromide to activate thioglycosides was also investigated. The cooperative use of these activation protocols was applied to a one-pot, two-step sequential activation, using thioimidate and thioglycoside building blocks.

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Stereospecific synthesis of 1,2-cis-glycosides of 2-amino sugars

Cited by 18 publications

References 8 publications

Nickel-Catalyzed Stereoselective Glycosylation with C(2)-N-Substituted Benzylidene d-Glucosamine and Galactosamine Trichloroacetimidates for the Formation of 1,2-cis-2-Amino Glycosides. Applications to the Synthesis of Heparin Disaccharides, GPI Anchor Pseudodisaccharides, and α-GalNAc

Nickel-Catalyzed Stereoselective Glycosylation with C(2)-N-Substituted Benzylidene d-Glucosamine and Galactosamine Trichloroacetimidates for the Formation of 1,2-cis-2-Amino Glycosides. Applications to the Synthesis of Heparin Disaccharides, GPI Anchor Pseudodisaccharides, and α-GalNAc

Recent trends in the synthesis of O-glycosides of 2-amino-2-deoxysugars

A study of silver (I) perchlorate as an effective promoter for chemical glycosylation with thioimidates and thioglycosides

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