Photoinduced Addition of Glycosyl Thiols to Alkynyl Peptides: Use of Free-Radical Thiol-Yne Coupling for Post-Translational Double-Glycosylation of Peptides

Double glycosylation of cysteine-containing peptides has been carried out by a one-pot two-step sequence comprising selective S-propargylation followed by photoinduced, (lambda(max) 365 nm) free-radical hydrothiolation with glycosyl thiols. Conditions were established for the sequential introduction of two different thiol residues such as a glycosyl and a biotinyl derivative.