Synthesis of cyclogentiotriose by macrocyclization via a ring-closing glycosylation

The synthesis of a benzylated cyclogentiotriose was achieved through the ring-closing glycosylation, which was developed by us recently. Moderate β-selectivity (3.3:1) was obtained in the 1,6 glycosidic linkage formation step. The α-acetoxy ether precursor was generated through the Rychnovsky reductive acetylation of a linear trisaccharide derived macrolactone.