Bioactive C-glycosides inspired from natural products towards therapeutics

Nature in its repertoire has presented several products, either O- or C-glycosylated. The scientific community continues to unravel the significance of appended glycosyl units. Marked difference between O -and C-glycosides in their hydrolytic stability and biological activity has been the prime reason for intense synthetic efforts during last three decades for synthesis of C-glycosides. Search for bioactive C-glycosides with therapeutic applications has started paying dividends. Following general introduction of glycosides present in nature, brief survey of C-glycosides of prominence in plant kingdom is covered. Success of recently approved drug, Dapagliflozin, and subsequent synthetic efforts for further structural modifications is presented. In the context that natural products in health dietary foods are being viewed as nutraceuticals towards disease prevention, synthesis of bioactive C-glycosides of flavones, chalcones, xanthones are covered. Under C-glycosides from non-plant sources, C-analog of Adenophostin A and KRN 7000 are covered as illustrative examples. The pioneering contribution towards chemical synthesis of C-analogs of KRN 7000 is presented, illustrating the challenges undertaken by synthetic community for access to promising bioactive C-glycosides. Finally a brief survey of readily synthesized C-1 functionalized building blocks for the synthesis of C-glycosides is presented.