Pure α-linked products can be obtained in high yields in glycosylation with glucosyl trichloroacetimidate donors with a C2 ester capable of neighboring group participation

Predominant or even pure (1→3)-α-linked products can be generated in glycosylation with glucosyl trichloroacetimidate donors with a C2 ester capable of neighboring group participation. Benzoylation of either the donors or acceptors gave more β-linkage, while 4,6-O-benzylidenation of the acceptor gave exclusive β-glucosylation. 3-O-Glycosylation of the donor and the presence of a (1→3)-β-linkage in the oligosaccharide acceptor gave sole α-glucosylation.