Synthesis of Isobenzofuranones by Cobalt Catalyzed [2+2+2] Cycloaddition

Highly regioselective cobalt catalyzed [2+2+2] cycloaddition of diynes and monoynes to afford isobenzofuranones in good yields is described. The reaction proceeds in the presence of cheap and readily available cobalt catalyst with a sterically hindered pyridine-2,6-diimine ligand. Applicability of the method can also be extended to the synthesis of isoindolinones.