Metal-ligand cooperative iridium complex catalyzed C-alkylation of oxindole and 1,3-dimethylbarbituric acid using alcohols

A general and high-efficiency C-alkylation of oxindoles and barbituric acids has been developed by a Cp∗Ir complex [Cp∗Ir (2,2′-bpyO)(OH)]Na with a bipyridine-based functional ligand. In particular, H2O was selected as the solvent instead of the organic solvent in this catalytic system. Through mild reaction conditions gave a variety of corresponding alkylated heterocyclic compounds with good to excellent yields. More importantly, the gram-scale C-alkylation reaction was successfully carried out with good yield using a common route with only a single purification by column chromatography