p‑Methoxybenzyl-Radical-Promoted Chemoselective Protection of sec-Alkylamides

The hitherto difficult site-selective p-methoxybenzylation of secondary amides using p-methoxybenzylated alkylsilyl peroxides as a novel p-methoxybenzylation agent under copper catalysis is reported. The reaction proceeds under mild reaction conditions in a highly chemoselective manner. This approach was successfully applied to the site-selective p-methoxybenzylation of peptides.