Ferrier glycosylation reaction catalyzed by Bi(OTf)3-montmorillonite K-10:: Efficient synthesis of 3,4-unsaturated sialic acid derivatives

The reaction of the 4,5-oxazoline derivative of sialic acid with various alcohols was effectively promoted by a catalytic amount of montmorillonite K-10 clay supported Bi(OTf)(3) to produce a variety of 3,4-unsaturated sialic acids via the Ferrier glycosylation reaction in moderate yields.