Hypervalent Iodine Mediated Oxidative Cyclization of Acrylamide N‑Carbamates to 5,5-Disubstituted Oxazolidine-2,4-diones

A metal-free oxidative cyclization of N-Boc-acrylamides with (diacetoxyiodo)­benzene in acetic acid produced 5,5-disubstituted oxazolidine-2,4-diones with the formation of a C–O bond in moderate to excellent yields. In addition, the reaction was diastereospecific with N-Boc-2,3-dimethylacrylamides and proceeded with phenyl migration in the case of an N-Boc-2-phenylacrylamide to generate a 5-acetoxy-5-benzyloxazolidine-2,4-dione.