Sialylation reactions with N,N-acetyl, benzoyl-O-perbenzoyl-protected sialyl donor

A new sialyl donor, N,N-acetyl, benzoyl-O-perbenzoyl-protected p-toluenethiosialoside, was synthesized and its sialylation reaction was investigated. This reaction proceeded in dichloromethane and β anomeric selectivity was achieved when NIS-TfOH was used as promoter. This method may be employed to construct the unnatural β-linked sialosides.