Synthesis of S-glycosyl amino acids and S-glycopeptides via photoinduced click thiol-ene coupling

We report on the photoinduced addition of glycosyl thiols to alkenyl glycines (thiol-ene coupling) to give S-glycosyl amino acids in high yields (53-90%). One of the amino acids thus prepared was used in the construction of a tripeptide via solution phase chemistry. Moreover, a one-pot two-step approach to an S-glycopeptide was developed using glutathione (GSH) as model starting material. This approach involved GSH S-alkenylation followed by photoinduced hydrothiolation by a glycosyl thiol.

S-Glucosyl glutathione was obtained by S-butenylation and photoinduced (UVA or sunlight) coupling with unprotected sugar thiol.