Serine/Threonine Ligation in Cyclizing Peptides

The increasing demands for the synthetic peptides and proteins have greatly advanced the method and strategy of chemical synthesis. In this Synpacts article, we will share our new ligation concept, serine/threonine ligation (STL), and the application in the synthesis of cyclic peptides, particularly backbone-constrained ­cyclic tetrapeptides. This ligation relies on the chemoselective reaction between N-terminal serine/threonine and a C-terminal salicylaldehyde ester.