Aerobic Oxidative Carbonylation of Enamides by Merging Palladium with Photoredox Catalysis.

Intramolecular oxidative carbonylation reaction is an efficient approach for constructing heterocycles. However, stoichiometric amount of hypervalent metal salts is usually required in this transformation. Here we show an aerobic intramolecular oxidative carbonylation of enamides by combining palladium and photoredox catalysis. The dual catalytic system enables oxygen directly as oxidant, which provides a mild and environmentally friendly method for the synthesis of 1,3-oxazin-6-ones.