M. Warwel et Wd. Fessner, Indium-mediated chain-extension: An improved protocol for the concise, diastereospecific synthesis of KDN and other sialic acids, SYNLETT, (6), 2000, pp. 865-867
Aqueous indium-mediated allylation of D-mannose with ethyl 2-(bromomethyl)a
crylate leads, under acidic conditions, exclusively to the threo products i
n high yields. A new purification procedure for indium-mediated reactions h
as been developed which is based on a simple precipitation of indium-contai
ning phosphate salts. This simplified protocol leads directly to diastereom
erically pure KDN and other sialic acids, thus obviating the need for the u
sual lengthy purification procedures.