Intramolecular glycosylation of prearranged glycosides part 5. α-(1→4)-Selective glucosylation of glucosides and glucosamines

Article abstract of DOI:10.1016/S0040-4039(97)00729-6

The intramolecular (1→4) glucosylation of partially protected alkyl glucosides and glucosamines with phenyl 1-thioglucoside that is preconnected via its position 2 by a succinyl spacer to positions 3 of the glucosyl acceptor affords the α-linked disaccharides. The anomeric selectivity depends on the stereochemistry of the donor-acceptor-interaction and is not governed by neighboring group participation. In contrast, connecting the glucosyl donor by the succinyl bridge to position 6 of the glucosamine acceptor results in an α/β-mixture of the corresponding disaccharides upon intramolecular glycosylation.