There has been increasing interest in the syntheses of carbohydrates due to their profound role in various biological processes and thus their potential in drug development. Various methods have been developed for the preparation of these oligosaccharides from simpler carbohydrate derivatives both chemically and enzymatically but they must be carefully applied to obtain the desired linkages. The main method that has been used to control the regioselectivity of glycosylations is protecting group chemistry. Unfortunately this requires additional steps lengthening the synthesis sequence. Extensive literature has shown the ability for carbohydrate recognition via organoboron methods through selective binding and their ability to undergo regioselective glycosylation through sugar-derived boronate esters. Exploiting these factors and in extension of previous work done in our laboratory on borinic acid- and boronic acid-catalyzed regioselective glycosylations of carbohydrate derivatives, we proposed a target oriented synthesis of a pentassacharide moiety found in four saponins isolated from Spergularia ramosa.

There has been increasing interest in the syntheses of carbohydrates due to their profound role in various biological processes and thus their potential in drug development. Various methods have been developed for the preparation of these oligosaccharides from simpler carbohydrate derivatives both chemically and enzymatically but they must be carefully applied to obtain the desired linkages. The main method that has been used to control the regioselectivity of glycosylations is protecting group chemistry. Unfortunately this requires additional steps lengthening the synthesis sequence. Extensive literature has shown the ability for carbohydrate recognition via organoboron methods through selective binding and their ability to undergo regioselective glycosylation through sugar-derived boronate esters. Exploiting these factors and in extension of previous work done in our laboratory on borinic acid- and boronic acid-catalyzed regioselective glycosylations of carbohydrate derivatives, we proposed a target oriented synthesis of a pentassacharide moiety found in four saponins isolated from Spergularia ramosa.