Ligand-Enabled C-H Olefination and Lactonization of Benzoic Acids and Phenylacetic Acids via Palladium Catalyst.

A novel ligand propan-2-one -(-tolylcarbamoyl) oxime () has been developed to promote C(sp)-H olefination of benzoic acids and phenylacetic acids via a palladium catalyst. With the subsequent lactonization of the olefinated products through 1,4-addition, highly monoselective cyclic lactone products of benzofuranones and benzopyrones were obtained in moderate to excellent yields. The DFT calculation demonstrated that the novel ligand propan-2-one -(-tolylcarbamoyl) oxime () could improve the C-H activation reaction to give cyclic lactone products elegantly.