Inversion of Configuration in 2,6-Dideoxy Sugars. Triflate Displacement by Benzoate and Nitrite Anions

Article abstract of DOI:10.1021/jo00012a020

Interconversion among 2,6-dideoxy sugars at room temperature has been accomplished in high yield.The eight possible methyl 3- and 4-O-benzoyl-2,6-dideoxy-β-D-hexopyranosides 1-8 have been interconverted using their corresponding triflates as intermediates.Triflates derived from compounds 1, 2, 7, and 8 undergo internal displacement by the neighboring benzoyl group, inverting configuration at the triflyloxy-bearing carbon atom.Triflates of compounds 3-6 do not experience internal reaction; however, configuration was inverted in these compounds at room temperature byreaction with tetrabutylammonium nitrite.To illustrate the value of these reactions in oligosaccharide synthesis, configuration was inverted in three disaccharides composed of 2,6-dideoxy sugar residues.