A mild and efficient amide formation reaction mediated by P(OEt)3 and iodine

With the activation of P(OEt)(3) and I-2, carboxylic acids can smoothly react with various primary and secondary amines, affording a series of amides, including peptides without racemization. P-31 NMR spectroscopy studies showed that carboxylic phosphoric mixed anhydride was the reactive intermediate and a possible mechanism was herein proposed.