Preparation of peptide thioesters using Fmoc strategy through hydroxyl side chain anchoring

In the course of the chemical synthesis of human protein mitogaligin, we present here a simple method to prepare peptide thioesters using Fmoc chemistry. The hydroxyl side chain of serine was reacted with a trichloroacetimidate Wang resin to anchor it on solid phase. After peptide elongation and orthogonal unmasking of the C-terminus, the amino thioester was introduced under optimized conditions to avoid epimerization.