2-Picolinic acid and benzoic acid from di-2-pyridyl ketone and acetophenone: A case of two copper catalysed Baeyer–Villiger rearrangements?

The synthesis and crystal structure elucidation of two novel polymeric copper(II) complexes has led us to propose a mechanism for the formation of 2-picolinic acid (pic) from di-2-pyridyl ketone (dpk) and benzoic acid from acetophenone. During studies into the interaction of copper ions with the dpk-acetophenone system, two complexes Na2(NCS)2(H2O)[Cu(pic)2] (1) and Na2(H2O)2[Cu(pic)2(NCS)2] (2) which contain pic coordinated to copper were isolated. The occurrence of (1) and (2) has led us to consider the Baeyer–Villiger rearrangement as a possible mechanism for the formation of (1) and (2).