Stereoselective Synthesis of 2-Deoxyglycosides from Glycals by Visible-Light-Induced Photoacid Catalysis

The direct, photoacid-catalyzed synthesis of 2-deoxyglycosides from glycals is reported. A series of phenol-conjugated acridinium-based organic photoacids were rationally designed, synthesized, and studied alongside the commercially available phenolic catalyst eosin Upsilon. In the presence of such a photoacid catalyst and light, synthetic glycals were activated and coupled with a range of alcohols to afford 2-deoxyglycosides in good yields and with excellent alpha-selectivity.