The role of titanium and iron complexes in the deoxygenation of aromatic nitroso-compounds

Abstract

Deoxygenation of aromatic nitroso-compounds RNO (R = Ph or biphenyl-2-yl) under very mild conditions by titanium(II) and titanium(III) derivatives such as [Ti(cp)₂(CO)₂], [{Ti(cp)₂Cl}₂], [Ti(cp)Cl₂](cp =η⁵-C₅H₅), and TiCl₃ led to the formation of oxo-complexes and the corresponding azo- and azoxy-organic compounds. Carbazole was not formed, suggesting a metal-controlled pathway for evolution of the plausible intermediate nitrene. Similar results have been obtained using N,N′-ethylenebis(salicylideneiminato)iron(II), [Fe(salen)], which was converted into [{Fe(salen)}₂O].