Development of a New NPPOC-Derived Photolabile Protecting Group Suitable for Cyclizations via Ring Closing Metathesis

Starting from 4-ethylguajacol in only 3–4 steps the new photolabile protecting group (PPG) precursors AMNPPol and AMNPPOCOCl can be obtained, which are suitable for the protection of the N- and the C-terminus of amino acids and peptides. The incorporated allyl functionality allows subsequent ring closing reactions with other unsaturations in the peptide. These protecting groups can be removed faster than the commonly used (substituted) nitrobenzyl protecting groups.