Abstract
Oligomannose glycans are of interest as HIV vaccine components but are subject to mannosidase degradation in vivo. Herein, we report the synthesis of oligosaccharides containing a thio linkage at the non-reducing end. A thio-linked dimannose donor participates in highly stereoselective glycosylations to afford tri- and tetramannose fragments. STD NMR studies show that these glycans are recognized by HIV antibody 2G12, and we confirm that the reducing terminal S-linkage confers complete stability against x. manihotis mannosidase.