Hydrogenolysis of Urethanes and Ureas Catalyzed by Manganese Complex Supported by Bidentate PN Ligand

Hydrogenolysis of less reactive carbonyl compounds such as urethanes and ureas is a challenging but promising transformation to utilize new chemical feedstocks, such as plastic waste and carbon dioxide fixation products. In these transformations, pincer-type complexes consisting of Ru and Mn have been intensively investigated but catalyst design with bidentate ligand systems has rarely been explored. We report here the synthesis of a Mn complex supported by a PN bidentate ligand consisting of phosphino and pyrrolido coordination sites, the molecular structure of which has been fully characterized. The Mn complex catalyzed the hydrogenolysis of urethanes and ureas. In the case of the hydrogenolysis of 1,3-diphenylurea, formanilide was obtained as a product. In addition, the present Mn complex did not promote the hydrogenation of carboxamides, showing a unique reactivity that preferentially reduces urethanes and ureas over carboxamides, in contrast to the general reactivity order of carbonyl compounds.