Application of 4,5-O,N-oxazolidinone protected thiophenyl sialosyl donor to the synthesis of α-sialosides

The synthesis of a novel oxazolidinone sialosyl donor is reported. The introduction of a trans-fused ring enhances reactivity and stereoselectivity in glycosylation reactions for the synthesis of α-sialosides. The oxazolidinone ring can also be removed under basic conditions to afford the deprotected amine, which can be further functionalized.