A de novo approach towards glycosylation using iterative Pd-/B-dual catalysis

Abstract

Carbohydrates containing natural products regularly play an impressive role in the biological activities, like target binding, tissue targeting, cell-cell interaction, cell-cell recognition and membrane transportation. Despite of the important biological properties, these highly complex oligosaccharide natural products are still challenging synthetic targets to make. The O'Doherty group has been using a de novo asymmetric approach to build on the desired functionality and chirality within the molecule starting from achiral moiety. The importance of this approach comes from the fact that all the stereocenter(s)/chirality in the molecule are built using an achiral starting material (2-acetyl furan), in contrast to the traditional approaches which starts from the known carbohydrate starting materials. This approach relies on a highly dia-stereoselective Palladium (0)-catalyzed glycosylation reaction to control the anomeric stereochemistry, followed by post-glycosylation transformations (Luche reduction, Upjohn dihydroxylation) to install the desired functionality and stereochemistry in the sugar moiety. In this regard, we have developed Pd-/B-dual catalysis for the regio- and stereo-selective synthesis of complex oligosaccharide class of natural products which in turn help us to expand the SAR network towards the anti-cancer studies.