Novel eco-friendly solution for the regioselective acetylation of per-O-TMS carbohydrates

Regioselective acetylation of per-O-TMS carbohydrates was achieved preferentially at the 6 position or 1,6-position under mild conditions involving the eco-friendly solvent acetonitrile, at room temperature, in ambient atmosphere and in a shorter time. Good or moderate yields were obtained via 4-dimethylaminopyridine, without auxiliary equipment. A single alpha-O-Acetyl acetylation anomer was exclusively defined for the involved substrates. A 6-O-monoacetate derivative was applied and used as a stable glycosyl donor in the disaccharides construction. The methodology was successful for a range of substrates, which include the following: D-lactose, D-trehalose, D-galactose, methyl alpha-D-galactose, D-glucose, D-mannose, D-xylose, and L-fucose.