Palladium-Catalyzed Multicomponent Reactions of o-Alkynylanilines, Aryl Iodides, and CO2 toward 3,3-Diaryl 2,4-Quinolinediones.

Palladium-catalyzed multicomponent reactions (MCRs) between o-alkynylanlines, aryl iodides, and atmospheric pressure of CO2 are developed, affording a series of 3,3-diaryl 2,4-quinolinediones bearing a newly constructed quaternary carbon center in moderate to excellent yields. The reaction proceeded with a sequential carboxylation, trans-oxopalladation of C≡C bond by ArPdX species, and reductive elimination procedure leading to benzoxazine-2-ones bearing tetrasubstituted vinyl fragments. Then, rearrangement of benzoxazine-2-ones took place toward 3,3-diaryl 2,4-quinolinediones. This procedure features simultaneous formation of four bonds in one pot.