786643-07-0Relevant academic research and scientific papers
Efficient transfer hydrogenation of ketones catalyzed by the bis(isocyanide)-ruthenium(II) complexes trans,cis,cis,-[RuX2(CNR) 2(dppf)] (X = Cl, Br; dppf = 14 -bis(diphenylphosphino)ferrocene): Isolation of active mono- And dihydride intermediates
Cadierno, Victorio,Crochet, Pascale,Diez, Josefina,Garcia-Garrido, Sergio E.,Gimeno, Jose
, p. 4836 - 4845 (2008/10/09)
The bis(isocyanide) - ruthenium(II) complexes trans,cis,cis-[RuX 2(CNR)2(dppf)] (X = Cl, R = CH2Ph (2a), Cy (2b), tBu (2c), 2,6-C6H3Me2 (2d), (S)-(-)-C(H)MePh (2e); X = Br, R = CH2Ph (3a), Cy (3b), tBu (3c), 2,6-C6H3Me2 (3d), (S)-(-)-C(H)MePh (3e)) have been prepared by reaction of the bis(allyl)-ruthenium(II) derivative [Ru(η3-2-C3H 4Me)2(dppf)] (1) with the appropriate isocyanide ligand, in CH2Cl2 at room temperature and in the presence of the corresponding hydrogen halide HX. The structure of the compound trans,cis,cis-[RuCl2(CN-2,6-C6H3Me 2)2(dppf)] (2d) has been confirmed by X-ray crystallography. The catalytic activity of complexes 2a-e and 3a-e in the transfer hydrogenation of acetophenone by propan-2-ol has been studied, and the most active complex, trans,cis,cis-[RuCl2(CNCH2Ph) 2(dppf)] (2a), has been also tested as a catalyst in the transfer hydrogenation of a large variety of ketones. The hydride derivatives cis,cis-[RuHCl(CN-2,6-C6H3Me2) 2(dppf)] (4) and cis,cis,cis-[RuHCl2(CN-2,6-C 6H3Me2)2(dppf)] (5) have been isolated and characterized. Although both hydride complexes catalyze the transfer hydrogenation of acetophenone in the absence of base, the reactions proceed ca. 5 times faster with 5 than with 4, pointing out that the real active species are dihydride-ruthenium complexes.
