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 α-O-Acetyl acetylation anomer was exclusively defined for the involved substrates.

Smart regioselectivity towards mono 6-hydroxyl α-cyclodextrin amphiphilic derivatives.

Following the trend of eco-friendly development, a smart regioselective modification is described herein, for mono 6-hydroxyl and penta-alkyl coexistence on the primary face of α-cyclodextrins with no additional catalysis or no enzyme process, just the adjustment of the ratio of alkali to alkylation agent, with good yields. The novel procedure minimized the tedious protection, deprotection steps and provided useful intermediates for further cutting edge research. Thus, the scope of green and economical access is extended from penta-pentenyl substitution to C-C alkyl group substitution.

Synthesis of oligosaccharides using per-O-trimethylsilyl-glycosyl iodides as glycosyl donor.

Trimethylsilyl (TMS) protecting group has been found to be very useful for the simultaneous protection of both the glycosyl donor- and the acceptor-substrates in oligosaccharide synthesis. Thus, while the per-O-trimethylsilylated glycosyl iodides served as the glycosyl donor, those bearing selectively exposed primary hydroxyl groups were found suitable as the glycosyl acceptor for the reaction. The cheap and commercially available trialkylamine, triethylamine was found to be an effective promoter for the glycosylation.