Synthesis and intramolecular glycosylation of sialyl mono-esters of o-xylylene glycol. The importance of donor configuration and nitrogen protecting groups on cyclization yield and selectivity; isolation and characterization of a N-sialyl acetamide indicative of participation by acetonitrile. (29th November 2016)

• Record Type: Journal Article
• Authors: Amarasekara, Harsha; Crich, David
• Is Part Of: Carbohydrate research. Volume 435(2016)
• Page Start: 113
• Page End: 120
• Publication Date: 2016-11-29
• Subjects: N-Glycosyl amide -- Lactonization -- Sialic acid -- Spirodiolide -- Thioglycoside -- Ritter reaction; Carbohydrates -- Periodicals; Chemistry, Organic -- Periodicals; Biochemistry -- Periodicals; Carbohydrates -- Periodicals; Chimie organique -- Périodiques; Glucides -- Périodiques; Biochemistry; Carbohydrates; Chemistry, Organic; Periodicals; Electronic journals; 507.78
• DOI: 10.1016/j.carres.2016.09.019
• Languages: English
• ISSNs: 0008-6215

Abstract

Abstract: The synthesis and cyclization reactions, leading to spirocyclic medium ring-sized diolides, of o -(hydroxymethyl)xylylene monoesters of sialyl thioglycosides is described. Cyclization yields and stereoselectivities are found to vary as a function of the anomeric stereochemistry of the thioglycoside and of the N5 protecting group, and these effects are discussed in terms of the reaction mechanism. Cyclization in the presence of acetonitrile results in the isolation and characterization of a Ritter-type N -sialyl acetamide, which affords strong evidence for the participation of acetonitrile in the form of sialyl nitrilium ions. Graphical abstract: Highlights: Intramolecular glycosylation leading to spirodiolide formation. Stereoselectivity of spirodiolide formation depends on anomeric configuration. Cyclization yield depends on N5-protecting group. Trapping of a sialyl nitrilium ion.