The epimerization can be reduced to a negligible degree, via a base-free activation step.doi:10.1017/S0003581500067573T Kaiser aG.J Nicholson bH.J Kohlbau aW Voelter aTetrahedron LettersKAISER E.A.: "Racemization studies of Fmoc-Cys-Trt-OH during stepwise Fmoc solid phase peptide synthesis" ...
Using the model peptide Z-Ala-Cys(PG)-Pro-OH, we studied the influence of coupling reagent, solvent, activation time, and temperature during preactivation and coupling on the racemization of Cys. SPPS was performed on H-Pro-2-chlorotrityl resin with 3 equiv. of amino acid derivative / ...