摘要 為了合成STn抗原及其類似物，我們找尋高度α選擇性及高產率的唾液酸予體進行醣基化反應，經文獻及一系列的醣基化反應的探討後，決定採用5-azido thio-glycoside，在NIS/TfOH催化下進行醣基化反應，用以合成STn抗原及其類似物。 除此之外，我們亦企圖利用azido group來修飾STn抗原，但卻發現5-azido phosphite-glycoside的活性極高，穩定性相對非常差，以致無法與N-acetyl-D-galactosamine行醣基化反應；於是改利用N-Troc phosphite-glycoside成功製備STn類似物；當中可發現予體5’官能基及受體所使用的保護基，對此醣基化反應的影響相當大。 Abstract N-Acetylneuraminic acid is found as the terminal sugar of many oligosaccharide chains on the cell surface and is among the most important residue for interactions with their receptors. In order to develop a universal sialic acid donor which can be easily functionalized at C-5 for chemical sialylation is of current interest. 5-Azido neuraminic acid thioglycoside with O-benzyl protecting groups was synthesized. The sialylations of this new donor type showed good α-selectivities for certain primary hydroxys. In another way, Sialyl-Tn and its analog were synthesized successfully with N-Troc neuraminic acid phosphiteglycoside. We found that reactivity of sialylations were affected by different protecting groups of donor and acceptor.