Abstract
Among 18 oxometallic species, MoO 2 Cl 2 was found to be the most reactive in catalytic thioglycosylation of O-acetylated glycosides with functionalized thiols in CH 2 Cl 2 , leading cleanly to 1,2-trans-thioglycosides with exclusive diastereocontrol. The new catalytic protocol is applicable to a monoglycoside building block and β-(1→6)-S-linked-thiodisaccharide synthesis. © 2006 American Chemical Society.