Stereoselective S-Sialoside Formation

SCHEME 5.21 Electrophilic C-sialidation with an W-acetyloxazolidinone-protected sialyl 

SCHEME 5.22 Stereoselective S-sialoside formation by reaction of a (1-sialyl chloride with a thiolate. DMF, V,V-dimethylformamide. 

The V-acetyloxazolidinone-protected sialyl phosphates have recently made possible the formation of complex S-sialosides under classical glycosylation 

SCHEME 5.23 Oligothiosialoside synthesis by iterative alkylation of a sialic acid-based anomeric thiolate. DIPEA, diisopropylethylamine. 

SCHEME 5.24 Sialylation of a thiol under Lewis acid-mediated conditions by an A-acetyl oxazolidinone-protected sialyl phosphate. 

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