Persulfate promoted carbamoylation of N-arylacrylamides with 4-carbamoyl-Hantzsch esters under metal-free conditions

4-Carbamoyl-Hantzsch esters were used as carbamoyl radical precursors for oxidative carbamoylation of N-arylacrylamides in the presence of inexpensive persulfates. This protocol can be applied for a broad range of substrates with various functional groups, whereas a variety of 3,3-disubstituted oxindoles were obtained in good yields via an intermolecular addition/cyclization process.