Coupling reaction with thiols as the efficient method of functionalization of ''clickable” polylactide

The effectiveness of coupling reactions with thiols proceeding under different conditions is compared as the method of polylactide functionalization. Metal-free syntheses of polylactides (PLAs) fitted at one chain end with unsaturated (allyl, propargyl or acrylate) groups were performed by applying acid catalyzed activated monomer polymerization of lactide using allyl and propargyl alcohols or hydroxyethyl acrylate as initiators. Functional PLAs were used for thiol-ene and thiol-yne reactions proceeding according to radical as well as nucleophilic addition. The coupling efficiency for thiols containing carboxyl groups (in comparison with model benzyl thiol) was investigated by MALDI TOF method.