262301-23-5Relevant articles and documents
Synthesis of S-linked carbohydrate analogues via a Ferrier reaction
Ellis, David,Norman, Sarah E.,Osborn, Helen M.I.
, p. 2832 - 2854 (2008/09/19)
In this work, the synthetic utility of the Ferrier reaction to access S-linked disaccharides and S-linked glycoamino acids has been probed. Significantly, entry to a range of 1,4- and 1,6-S-linked disaccharides has been achieved using glycals derived from glucose and galactose, and sulfur containing coupling partners derived from methyl α-d-glucopyranoside. Access to S-linked glycoamino acids and glycopeptides has also been achieved using protected cysteine and homocysteine coupling partners within the Ferrier reaction. Functionalisation of the Ferrier products, for example, via dihydroxylation using OsO4 or amino acid coupling, and deprotection of the targets have also been achieved. In this way, entry to materials of interest as mimics of biologically interesting disaccharides and glycopeptides has been realised, including targets derived from rare sugars such as talopyranose and gulopyranose.
Direct stereoselective synthesis of β-thiomannosides
Crich, David,Li, Hongmei
, p. 801 - 805 (2007/10/03)
A highly diastereoselective synthesis of β-thiomannopyranosides is described in which S-phenyl 2,3-di-O-benzyl-4,6-O-benzylidene-1-deoxy-1-thia- α-D-mannopyranoside S-oxide is treated with triflic anhydride and 2,6-di- tert-butyl-4-methylpyridine in CH2Cl2 at -78 °C leading to the formation of an intermediate α-mannosyl triflate. Addition of primary, secondary, or tertiary thiols then leads to the β-thiomannosides, by an S(N)2-like displacement, in good yield and with excellent stereoselectivity. Deprotection is achieved either by Birch reduction or by Zemplen deacetylation, of the acetyl protected aglycons, followed by hydrogenolysis over Pearlman's catalyst. The assignment of configuration of the β- thiomannopyranosides is discussed in terms of the chemical shift of the mannose H5 resonance and the 1J(CH) of the mannose anomeric carbon.
