Ru<sub>3</sub>(CO)<sub>12</sub>-Catalyzed Intermolecular Cyclocoupling of Ketones, Alkenes or Alkynes, and Carbon Monoxide. [2 + 2 + 1] Cycloaddition Strategy for the Synthesis of Functionalized γ-Butyrolactones
The ruthenium-catalyzed intermolecular cyclocoupling of ketones (or aldehydes), alkenes (or alkynes), and CO, which leads to γ-butyrolactones, is described. The reaction represents the first example of the catalytic synthesis of heterocycles via an intermolecular carbonylative [2 + 2 + 1] cycloaddition. A wide variety of ketones, such as α-dicarbonyl compounds and N-heterocyclic ketones, can be used