HI/Acetic acid reduction of peracetylated N-acetyl neuraminic acid esters to stereoselectively provide α-2-deoxy-2-hydrido derivatives

Article abstract of DOI:10.1016/S0040-4039(97)01323-3

Peracetylated ester derivatives of N-acetyl neuraminic acid were reacted with hydrogen iodide in acetic acid to stereoselectively provide α-2-deoxy-2-hydrido analogs, The reaction proceeds through formation of an anomeric iodide which, in the presence of excess HI, is reduced to give an enol intermediate, Kinetic protonation of the intermediate enol gives a 3.4:1 α:β mixture of 2-deoxy-2-hydrido derivatives. Under thermodynamic conditions the a-anomer is formed exclusively.