2‐Arylacetamides as Versatile Precursors for 3‐Aminoisocoumarin and Homophthalimide Derivatives: Palladium‐Catalyzed Cascade Double Carbonylation Reactions

The synthesis of biologically relevant homophthalimide and 3‐aminoisocoumarin nuclei via palladium‐catalyzed carbonylation of 2‐(2‐iodoaryl)acetamides has been developed. The degree of N‐substitution on the starting amide substrate dictates whether C−N or C−O coupling takes place in the final step of the catalytic cycle giving rise to each type of heterocycle. The introduction of a second C−halogen bond in the starting acetamides allows a catalytic cascade double carbonylation involving a C−H activation step to give fused heterocyclic structures.