TentaGel® resins are grafted copolymers consisting of a low crosslinked polystyrene matrix on which polyethylene glycol (PEG or POE) is grafted via an ethyl ether group which increases stability towards acid treatment and minimizes PEG-leaching. The graft copolymer shows modified physicochemical properties which are highly dominated by the PEG moiety (and no longer by the polystyrene matrix) and has hydrophobic and hydrophilic properties. These copolymers are pressure stable and can be used in batch processes as well as under continuous flow conditions. The PEG spacer is in the range of MW 3000 Da. TentaGel® resins have high diffusion rates and excellent swelling in a wide range of solvents from e.g. toluene to water. This resin contains the Dawson MeDbz Rink Amide linker attached to amino TentaGel® resin. It is a new type of support for the synthesis of C-terminal peptide aryl thioesters by Fmoc SPPS. When peptide assembly is finished in a follow up reaction a cyclic N-acylurea is formed which can either be converted to the desired aryl thioester by aryl thiol or directly used in native chemical ligation without prior isolation of the intermediate precursor.