Visible‐Light‐Induced Photoredox Dehydrative Coupling/Cyclization of N‐Arylacrylamides with Hydroxyketones

A mild visible‐light induced 4CzIPN/H+ photoredox system has been developed that enables hydroxyketones serving as a carbon radical precursor via formal C−O bond cleavage. This process was successfully exploited in the coupling/cyclization reaction of N‐arylacrylamides and thereby provided a viable access to acyl oxindoles. This protocol features advantages including no need for any metal catalyst and additive, high yielding, broad substrate scope, gram scalability, and release of H2O as the sole byproduct.