An Ezomycin Model Glycosylation

Article abstract of DOI:10.1021/jo00096a022

A model glycosylation reaction for application to the synthesis of the ezomycin class of antibiotics is described.The ezoaminuroic thioglycoside donor 13, with a reduced and protected C-6 position and trifluoroacetamide at C-3, was prepared from the Cerny epoxide 7 by a nine-step procedure.The model D-gulo-pyranoside acceptor 20, which closely resembles an actual acceptor in the vicinity of the reacting axial hydroxyl, was synthesized from methyl β-D-galactopyranoside 14.Glycosylation with N-iodosuccinimide/triflic acid as promoter gave the disaccharide 21 in 90percent yield.