A facile synthesis of 2-deoxy-2,3-didehydroneuraminic acid derivatives

The 2-thio- or 2-selenoglycosides of N-acetylneuraminic acid methyl ester were transformed by successive treatment with dimethyl(methylthio)sulfonium triflate (DMTST) and 1,8-diazabicyclo[5.4.0]-7-undecene (DBU) to give the corresponding methyl 2-deoxy-2,3-didehydroneuraminates in excellent yields. Their acids and their analogues are sialidase inhibitors of pharmaceutical interest.