Intramolecular carbonylative coupling of ketones^a.

^aReaction conditions: 1 (0.1 mmol), Co₂(CO)₈ (0.01 mmol, 10 mol%), IMes·HCl (0.02 mmol, 20 mol%), Cs₂CO₃ (0.04 mmol, 40 mol%), dioxane (0.5 mL) at 150 °C, 36 h in a sealed tube, isolated yields.

^bPCy₃ as the ligand and toluene as the solvent.

^cICy as ligand.