Palladium-catalyzed tandem carbonylative synthesis of indeno[1,2-b]indol-10(5H)-one scaffolds from 2-alkynylanilines

A novel palladium-catalyzed tandem cyclization and carbonylation of 2-alkynylanilines has been developed for the construction of indeno[1,2-b]indol-10(5H)-one scaffolds. By using formic acid as the CO source, this reaction proceeded smoothly to afford various indeno[1,2-b]indol-10(5H)-one derivatives in high yields. Notably, this protocol can be used in modifications of several bioactive molecules.