Efficient and stereocontrolled preparation of a library of variously sulfated biotinylated tetra- and pentasaccharides possessing the backbone of the partial linkage region plus the first chondroitin sulfate mono- or disaccharide unit (d-GlcA)n-β-d-(1,3)-GalNAc-β-d-(1,4)-GlcA-β-d-(1,3)-Gal-β-d-(1,3)-Gal (n = 0 or 1) is reported herein for the first time. The synthesis of these compounds was achieved using common key intermediates and a disaccharide building block obtained by semisynthesis. Stereoselective glycosylation, selective protection/deprotection steps, efficient reduction of the N-trichloroacetyl group into the corresponding N-acetyl group, efficient sulfation strategy, deprotection and biotinylation afforded target oligomers in good yield with high purity.
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