Visible-Light-Promoted Stereoselective C(sp 3 )-H Glycosylation for the Synthesis of C-Glycoamino Acids and C-Glycopeptides.

The glycosylative modification of peptides could improve the pharmacological properties of peptide drugs and deliver them efficiently to the target sites. Compared with O-/N-glycosides, C-glycosides exhibit more metabolic stability. We here disclose the first example of visible-light-promoted and Cu-catalyzed stereoselective C-glycosylation. The mild reaction conditions are compatible with various carbohydrate substrates, as demonstrated with a series of monosaccharides and a disaccharide, and are amenable to the synthesis of a wide variety of C-glycoamino acids and C-glycopeptidomimetics with good yields and excellent stereoselectivities. The dual-functional photocatalyst formed in situ via coordination of the glycine derivative and the chiral phosphine Cu complex could not only catalyze the photoredox process but also control the stereoselectivity of the glycosylation reaction.