Electrochemical C-H phosphorylation of 2-phenylpyridine in the presence of palladium salts

A new approach was developed to the introduction of the phosphonate group into arylpyridines using 2-phenylpyridine as an example. The approach is the electrochemical oxidation of a mixture of 2-phenylpyridine, diethyl phosphite, and palladium acetate at room temperature. An intermediate dipalladium cyclic complex was isolated that is formed by the ortho-palladation of 2-phenylpyridine and substitution of acetate ions by phosphonate ions. The preparative oxidation of this complex selectively results in the product of the phosphorylation of the C-H bond in 2-phenylpyridine.