Regiodiverse Three-Component Synthesis of Arenes

A ruthenium‐catalyzed enyne metathesis reaction followed by a cobalt‐catalyzed Diels–Alder reaction and oxidation of the dihydroaromatic intermediate generates the two regioisomeric aromatic products in good overall yields in a one‐pot procedure. The regiochemistry of the cycloaddition can be controlled by the ligand choice on the cobalt catalyst to generate the product with the 1,3,5‐ or the 1,2,4‐substitution pattern predominantly. The high functional group tolerance was used to generate bifunctionalized building blocks and finally an unprecedented regioselective Scholl reaction is described.