title: Improvement of the stereoselectivity of the glycosylation reaction with 2-azido-2-deoxy-1-thioglucoside donors.
abstract: 2-Azido-2-deoxy-1-thioglucoside donors with an electron withdrawing group at position 6 were employed to study the stereoselectivity of the glycosylation reaction with several acceptors, ranging from unhindered small primary alcohols to other sugars and steroids, using NIS/TfOH as promoter. p-Tolyl 2-azido-3,4-di-O-benzyl-6-O-chloroacetyl-2-deoxy-1-thio-α/β-D-glucopyranoside afforded the higher α-selectivity, showing that a stronger electron withdrawing ester at O-6 influenced the anomeric selectivity towards the 1,2-cis glucosides. The anomeric stereoselectivity was highly dependent on the acceptor.
authors.affiliation: Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. Da República, EAN, 2780-157 Oeiras, Portugal.
authors.forename: E C
authors.initials: EC
authors.lastname: Lourenço
authors.affiliation: Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. Da República, EAN, 2780-157 Oeiras, Portugal. Electronic address: rventura@itqb.unl.pt.
authors.forename: M R
authors.initials: MR
authors.lastname: Ventura
mesh_terms: D000438:Alcohols / Q000737:chemistry*; D002236:Carbohydrate Conformation; D002241:Carbohydrates / Q000737:chemistry*; D006031:Glycosylation; D013237:Stereoisomerism; D013256:Steroids / Q000737:chemistry*; D013863:Thioglucosides / Q000737:chemistry*
chemical_list: C000613146:2-azido-2-deoxy-1-thioglucoside; D000438:Alcohols; D002241:Carbohydrates; D013256:Steroids; D013863:Thioglucosides
keywords: 1,2-cis Glycosides; 2-Azido-2-deoxy-1-thioglucosides; Glycosylation reaction; α-2-Azido-2-deoxy-glucosides