Catalytic Ability of a Cationic Ru(II) Monochloro Complex for the Asymmetric Hydrogenation of Dimethyl Itaconate and Enamides
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- 作者：Isabel Serrano ; Montserrat Rodrí ; guez ; Isabel Romero ; Antoni Llobet ; Teodor Parella ; Juan M. Campelo ; Diego Luna ; José ; M. Marinas ; and Jordi Benet-Buchholz
- 刊名：Inorganic Chemistry
- 出版年：2006
- 出版时间：March 20, 2006
- 年：2006
- 卷：45
- 期：6
- 页码：2644 - 2651
- 全文大小：134K
- 年卷期：v.45,no.6(March 20, 2006)
- ISSN：1520-510X
文摘
The synthesis of two Ru chloro complexes, RuIIICl3(bpea), 1, and cis-fac-
-[RuIICl{(R)-(bpea)}{(S)-(BINAP)}](BF4), cis-fac--(R)-(S)-2, (bpea = N,N-bis(2-pyridylmethyl)ethylamine; (S)-BINAP = 2,2'-bis(diphenylphosphino)-1,1'-binaphthyl), is described. Complex 2 is characterized in solution through UV-vis, cyclic voltammetry (CV), and1D and 2D NMR spectroscopy. X-ray diffraction analysis indicates that in the solid state it possesses the samestructure as in solution, as expected for a low-spin d6 Ru(II)-type complex. The molecular structure of cis-fac--(R)-(S)-2, consists of a nonsymmetric complex, where the Ru metal center has a significantly distorted octahedral-type coordination because of the bulkiness of the (S)-BINAP ligand. cis-fac--(R)-(S)-2 has a remarkable catalyticperformance at P = 6.8 atm of H2 and T = 70 
C toward the hydrogenation of prochiral double bonds both fromefficiency and from stereoselectivity viewpoints. As an example, prochiral olefins of technological interest such asdimethyl itaconate, methyl 2-acetamidoacrylate or methyl 2-acetamidocinnamate are catalytically hydrogenated bycis-fac--(R)-(S)-2, with conversions higher than 99.9% and ee > 99. Furthermore, cis-fac--(R)-(S)-2, also catalyzesthe selective hydrogenation of 
-keto esters, although the reaction rates are lower than those found with theformer substrates.
-[RuIICl{(R)-(bpea)}{(S)-(BINAP)}](BF4), cis-fac--(R)-(S)-2, (bpea = N,N-bis(2-pyridylmethyl)ethylamine; (S)-BINAP = 2,2'-bis(diphenylphosphino)-1,1'-binaphthyl), is described. Complex 2 is characterized in solution through UV-vis, cyclic voltammetry (CV), and1D and 2D NMR spectroscopy. X-ray diffraction analysis indicates that in the solid state it possesses the samestructure as in solution, as expected for a low-spin d6 Ru(II)-type complex. The molecular structure of cis-fac--(R)-(S)-2, consists of a nonsymmetric complex, where the Ru metal center has a significantly distorted octahedral-type coordination because of the bulkiness of the (S)-BINAP ligand. cis-fac--(R)-(S)-2 has a remarkable catalyticperformance at P = 6.8 atm of H2 and T = 70 C toward the hydrogenation of prochiral double bonds both fromefficiency and from stereoselectivity viewpoints. As an example, prochiral olefins of technological interest such asdimethyl itaconate, methyl 2-acetamidoacrylate or methyl 2-acetamidocinnamate are catalytically hydrogenated bycis-fac--(R)-(S)-2, with conversions higher than 99.9% and ee > 99. Furthermore, cis-fac--(R)-(S)-2, also catalyzesthe selective hydrogenation of -keto esters, although the reaction rates are lower than those found with theformer substrates.