Exploiting an aromatic aglycone as a reporter of glycosylation stereochemistry in the synthesis of 1,6-linked maltooligosaccharides

Analysis of glycosylation stereoselectivity in the synthesis of branched maltooligosaccharides is hampered by poor spectral dispersion due to the repetitive nature of the saccharide chain and overlap of sugar H-1 signals with benzylic proton signals from the typically used benzyl ether protecting groups. A suitably protected p-methoxyphenyl maltoside acceptor, when coupled with benzylated maltooligosaccharide donors, gives discrete aglycone ¹H NMR signals that can be used to report on the stereoselectivity of 1,6-glycosylation reactions.