Rhodium-Catalyzed Oxidative Decarboxylation Annulation Reactions of Mandelic Acids and Alkynes: an Efficient Synthetic Method for Indenones

Efficient rhodium-catalyzed oxidative decarboxylation annulation reactions between mandelic acids and alkyne derivatives are described. The desired indenone products were obtained in medium to good yields under the optimized reaction conditions, which were a [RhCp*Cl-2](2) catalyst (10.0 mol %) in combination with a PCy3 ligand (10.0 mol %) and AgSbF6 (10 mol %) and Cu(OAc)(2) (20 mol %) additives. Many functional groups are compatible with the reaction under the optimized reaction conditions. This strategy provides a promising method for the construction of indenones from cheap and commercially available starting materials.