Palladium-Catalyzed Multi-Component Reactions of N-Tosylhydrazones, 2-Iodoanilines and CO2 towards 4-Aryl-2-Quinolinones

A palladium‐catalyzed three‐component reaction between N‐tosylhydrazones, 2‐iodoanilines and atmospheric pressure CO2 was developed whereby a tandem carbene migration insertion/lactamization strategy afforded 4‐aryl‐2‐quinolinones in moderate to good yields. Notably, a wide range of functional groups were tolerated in this procedure. This protocol features the simultaneous formation of four novel bonds; two C−C, one C=C and one C−N (amide), representing an efficient methodology for incorporation of CO2 into heterocycles. Three become one: A palladium‐catalyzed three‐component reaction between N‐tosylhydrazones, 2‐iodoanilines and CO2 at atmospheric pressure was developed whereby a tandem carbene migration insertion/lactamization strategy to afford 4‐aryl‐2‐quinolinones could be isolated in moderate to good yields (see scheme). This protocol features the simultaneous formation of four novel bonds; two C−C, one C=C and one C−N (amide), representing an efficient methodology for incorporation of CO2 into heterocycles.