De novo approach to 2-deoxy-β-glycosides:: Asymmetric syntheses of digoxose and digitoxin

A highly enantioselective and straightforward route to trisaccharide natural products digoxose and digitoxin has been developed. Key to this approach is the iterative application of the palladium-catalyzed glycosylation reaction, reductive 1,3-transposition, diastereoselective dihydroxylation, and regioselective protection. The first total synthesis of natural product digoxose was accomplished in 19 total steps from achiral 2-acylfuran, and digitoxin was fashioned in 15 steps starting from digitoxigenin 2 and pyranone 8 beta. This flexible synthetic strategy also allows for the preparation of mono-and disaccharide analogues of digoxose and digitoxin.