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)-alpha-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 beta-linkage, while 4,6-O-benzylidenation of the acceptor gave exclusive beta-glucosylation. 3-O-Glycosylation of the donor and the presence of a (1-->3)-beta-linkage in the oligosaccharide acceptor gave sole alpha-glucosylation. (C) 2002 Elsevier Science Ltd. All rights reserved.