Direct β-acyloxylation of enamines via PhIO-mediated intermolecular oxidative C-O bond formation and its application to the synthesis of oxazoles.

A direct β-acyloxylation of enamine compounds has been achieved by using iodosobenzene (PhIO) as an oxidant to realize the intermolecular oxidative C(sp(2))-O bond formation between enamines and various carboxylic acids, including N-protected amino acids. The transformation tolerates a wide range of functional groups and furnishes a variety of β-acyloxy enamines that can be conveniently converted to oxazole compounds via cyclodehydration.