Palladium-Catalyzed C-C Triple Bond Cleavage: Efficient Synthesis of 4H-Benzo[d][1,3]oxazin-4-ones

Described herein is a new transformation of azidoalkynes by using a palladium catalyst, which involves a tandem process of aminopalladation of the alkyne and oxidative rearrangement. The reaction affords a variety of 4H-benzo[d][1,3]oxazin-4-ones. Mechanism studies support a Pd-catalyzed aminopalladation/oxidation/Baeyer-Villiger fragmentary sequence.