A copper-catalysed (diacetoxyiodo)benzene-promoted aerobic esterification reaction of acetoacetamides was developed for the synthesis of oxamates, which are useful precursors in synthetic organic chemistry. This practical and mild synthetic approach proceeded at 25 8C under open-air conditions and afforded methyl 2-oxo-2-(phenylamino)acetates in good to excellent yields combined with CÀC s-bond cleavage and formal oxidative CÀH bond functionalization. A mechanism is proposed.