Novel Molecular Clamp Method for Anomeric Stereocontrol of Glycosylation

Abstract

Stereocontrolled glycosylation is described by using a molecular clamp, which binds a glycosyl donor to an acceptor and controls their spatial arrangement. An α(1 → 4) glycosidic linkage was formed in a good yield with high selectivity by the use of phthaloyl bridge bound to both 6-positions of a glycosyl donor and an acceptor. β-Selective glycosylation was effected by the use of a silyl bridge attached to the same 6-positions of the same glycosyl donor and acceptor. Application of this method to the synthesis of a maltotetraose derivative is also described.