Dehydrative Glycosylation with Activated Diphenyl Sulfonium Reagents. Scope, Mode of C(1)-Hemiacetal Activation, and Detection of Reactive Glycosyl Intermediates

Autor:	Brian A. Garcia and, David Y. Gin
Rok vydání:	2000
Předmět:	Glycosylation Anomer Sulfonium General Chemistry Biochemistry Combinatorial chemistry Catalysis carbohydrates (lipids) chemistry.chemical_compound Colloid and Surface Chemistry chemistry Reagent Hemiacetal lipids (amino acids peptides and proteins) Glycosyl Glycosyl donor Triflic acid
Zdroj:	Journal of the American Chemical Society. 122:4269-4279
ISSN:	1520-5126 0002-7863
Popis:	The development of a method for direct dehydrative glycosylations with 1-hydroxyglycosyl donors employing the reagent combination of triflic anhydride and diphenyl sulfoxide is described. The one-pot coupling method is a facile process which is applicable to a variety of carbohydrate coupling partners. Oxygen-18-labeling studies are consistent with the first step in carbohydrate activation being the formation of an anomeric oxosulfonium intermediate. This reactive glycosyl species (35) is observable in low-temperature NMR experiments when 2,3,4,6-tetra-O-methyl-d-mannopyranose is activated as the glycosyl donor. When the dehydrative glycosylation reaction is performed in the presence of the triflic acid scavenger 2-chloropyridine, NMR analysis reveals that the glycosyl oxosulfonium intermediate 35 is converted to the corresponding anomeric 2-chloropyridinium species 36.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_________::93efdb63c2ce6253a70081f2ed25c3ab https://doi.org/10.1021/ja993595a Zobrazit plný text záznamu