Oxidative CO Cross‐Coupling of 1,3‐Dicarbonyl Compounds and Their Heteroanalogues with N ‐Substituted Hydroxamic Acids and N ‐Hydroxyimides

The oxidative CO cross‐coupling of 1,3‐dicarbonyl compounds and their heteroanalogues, 2‐substituted malononitriles and cyanoacetic esters, with N ‐substituted hydroxamic acids and N ‐hydroxyimides was realized. The best results were obtained with the use of manganese(III) acetate [Mn(OAc) 3 ] or the cobalt(II) acetate catalyst [Co(OAc) 2cat. ]/potassium permanganate [KMnO 4 ] system as the oxidant. The synthesis can be scaled up to gram quantities of coupling products; yields are 30–94%. The reaction proceeds via a radical mechanism through the formation of nitroxyl radicals from N ‐substituted hydroxamic acids and N ‐hydroxyimides.