Lewis acid–nitromethane complex-promoted Friedel–Crafts reactions of PS-DVB-resins

Aminomethyl-polystyrene resins were prepared using FeCl3–nitromethane and FeCl3–benzophenone complexes as Friedel–Crafts catalysts. All the resins were highly loaded and functionalized with Rink amide linker. A comparative synthesis of the classic difficult sequence ACP (65–74) on the prepared resins by Fmoc/t-Bu chemistry is presented. The target peptide of highest purity (91%) was that prepared using FeCl3–nitromethane.