C–H bond functionalizations with palladium(II): intramolecular oxidative annulations of arenes

Oxidative annulations for the synthesis of carbocycles were developed using a catalytic palladium(II) system. Indoles with pendant olefin tethers were oxidatively cyclized to form annulated products. Electron-rich aromatic systems were also investigated, culminating in the synthesis of benzofurans and dihydrobenzofurans by a similar protocol. These reactions were demonstrated to proceed by an initial C–H bond functionalization event, followed by olefin insertion and β-hydride elimination.