Metallation of hydroxy-aryl and -alkyl compounds by reaction with dodecacarbonyl-triangulo-triosmium

Abstract

Various organic hydroxy-compounds ROH react with [OS₃(CO)₁₂] at 140 °C to give species of type [Os(CO)₁₀H(OR)](R = Ph, 2-naphthyl, CHMe₂. CH₂Ph, CHMePh, or CMe₂Ph), some of which convert at higher temperatures into the dihydrides [Os₃(CO)₉H₂(X)], the second metal hydride being derived from R. Where hydrogen-atom transfer is from the β-carbon atom, compounds containing the triply bridged ligand X (X = OC₆H₄, 2-OC₁₀H₆, 1-OC₁₀H₆, or OC₆H₃OH-o) are formed, whereas γ-carbon–hydrogen bond cleavage gives species with X bridging two osmium atoms and forming a five-membered chelate ring with one of them (X = OCMe₂C₆H₄, OCHMeC₆H₄, or 1-OC₁₀H₆). The spectroscopic evidence for these conclusions is discussed.