Highly efficient selective S-deacetylations were achieved by simple transthioesterification under mild basic conditions.

Latent O-glycosides, 2-(2-propylthiol)benzyl (PTB) glycosides, were converted into the corresponding active glycosyl donors, 2-(2-propylsulfinyl)benzyl (PSB) glycosides, by a simple and efficient oxidation. Treatment of the PSB donor and various acceptors with triflic anhydride provided the desired glycosides in good to excellent yields. The leaving group, which was activated by an interrupted Pummerer reaction, can be recycled (PSB-OH) and regenerated as the precursor (PTB-OH). A natural hepatoprotective glycoside, leonoside F, was efficiently synthesized in a convergent [3+1] manner with this newly developed method. The present total synthesis also led to a structural revision of this phenylethanoid glycoside.

2-Deoxy sugars and their derivatives occur abundantly in many pharmaceutically important natural products. However, the construction of specific 2-deoxy-glycosidic bonds remains as a challenge. Herein, we report an efficient way to prepare 2-deoxy-α-glycosides by glycosylation of 2-iodo-glycosyl acetate and subsequent visible-light-mediated tin-free reductive deiodination. We have successfully applied the postglycosylational-deiodination strategy in the synthesis of more than 30 mono-, di-, tri-, tetra- and pentadeoxysaccharides with excellent stereoselectivity and efficiency. This method has also been applied to the synthesis of a 2-deoxy-tetrasaccharide containing four α-linkages.

Latent O‐glycosides, 2‐(2‐propylthiol)benzyl (PTB) glycosides, were converted into the corresponding active glycosyl donors, 2‐(2‐propylsulfinyl)benzyl (PSB) glycosides, by a simple and efficient oxidation. Treatment of the PSB donor and various acceptors with triflic anhydride provided the desired glycosides in good to excellent yields. The leaving group, which was activated by an interrupted Pummerer reaction, can be recycled (PSB‐OH) and regenerated as the precursor (PTB‐OH). A natural hepatoprotective glycoside, leonoside F, was efficiently synthesized in a convergent [3+1] manner with this newly developed method. The present total synthesis also led to a structural revision of this phenylethanoid glycoside.

New glycosyl donors with recyclable and regenerable leaving groups, which could be activated via remote mode, were designed for latent-active glycosylation.