Acid-Catalyzed O-Glycosylation with Stable Thioglycoside Donors.

Two classes of thioglycoside, 4-(4-methoxyphenyl)-3-butenylthioglycosides (MBTGs) and 4-(4-methoxyphenyl)-4-pentenylthioglycosides (MPTGs), undergo acid-catalyzed O-glycosylations with a range of sugar and nonsugar alcohols at 25 °C. Electron density at the styrene alkene is critical for reactivity while sugar protecting group patterns have a minimal effect. In contrast with most methods for thioglycoside activation, acid-catalyzed activation of MBTGs is compatible with electroneutral alkenes.