Organic compounds -- part of the class 532-570 series – Organic compounds – Heavy metal containing
Patent
1992-02-21
1994-06-28
Dees, Jose G.
Organic compounds -- part of the class 532-570 series
Organic compounds
Heavy metal containing
556136, C07F 1500
Patent
active
053248503
DESCRIPTION:
BRIEF SUMMARY
The invention relates to the preparation of optically active catalysts formed by ruthenium complexes in which the ligand is an organic phosphorus derivative. It relates in particular to asymmetric hydrogenation catalysts and double bond isomerization catalysts which make it possible to obtain organic products of desired chirality. The method according to the invention makes it possible to obtain products of improved optical purity in cases where the latter is inadequate when applying the catalysts obtained according to the prior art. The catalysts formed by the method according to the invention are very advantageously suitable for the preparation of amino acids, and particularly L-threonine, by hydrogenation of the corresponding ketones, and in general of compounds carrying a carbonyl and an amine or amide group.
At the present time, various phosphine complexes of Ru are known which are used as asymmetric hydrogenation catalysts. An example of such a complex is bis(2-methylallyl)bis(triphenylphosphine)Ru, which is described by J. POWELL and B. L. SHAW in Journ. Chem. Soc. n.degree. A, 1968, pages 159-161. In the literature on this subject, the useful organophosphorus ligands are denoted by abbreviations such as DIOP, DIPAMP, CHIRAPHOS, BINAP etc., which are generally phosphines such as, for example, ##STR1## i.e. 1,2-bis(o-anisylphenylphosphino)ethane, wherein OAn is o-anisyl. In general, these ligands are combined with a halide or an organic compound of Ru, especially a carboxyl or unsaturated group and in particular an allyl group.
Thus R. NOYORI et al.--J. Amer. Chem. Soc. 1987, 109, pages 5856-5858--have described the asymmetric hydrogenation of several carboxylic acid esters carrying a ketone group in the .beta. position, converting said group to a hydroxyl according to the equation ##STR2## the catalyst being RuX.sub.2 [(R or S)-BINAP], where BINAP denotes the diphosphine ##STR3## X being Cl, Br or I.
Depending on the R or S configuration of this ligand, the authors obtained the .beta.-hydroxyester mainly in one or other of these configurations, the enantiomeric purity always being very high.
Likewise, M. KITAMURA et al., in J. Am. Chem. Soc. 1988, 110, pages 629-631, have reported similar asymmetric hydrogenations, with the same catalyst, carried out on substances in which the --CH.sub.2 --COOR' in the formula given above is replaced with --CH.sub.2 --N(R').sub.2, CH.sub.2 --OH, CH.sub.2 --CH.sub.2 OH, CH.sub.2 --COSR', --CH.sub.2 --COR', --CH.sub.3 CO, --C.sub.6 H.sub.4 -- COOH, CH.sub.3, --CO--CH.sub.3, --CH.sub.2 --COR' or ##STR4## In these cases too, the yields of the hydrogenation are in general very high, as is the optical purity (% enantiomeric excess, e.e.).
However, it is found that if an attempt is made to carry out the same reactions with catalysts in which the BINAP group is replaced with a more economic group, for example one of those referred to above, the results become random and less satisfactory. The work from which the present invention is derived suggests that this disadvantage is due to the degradation undergone by the products during the preparation of the catalyst, which comprises heating a ruthenium compound with a phosphine. In fact, the article by TETSUO OHTA et al., Inorg. Chem. 1988, 27, page 567, or that by Takao IKARIYA et al., J. Chem. Soc., Chem. Commun. 1985, page 922, states that to prepare complexes of Ru with BINAP, a ruthenium compound is heated with the phosphine BINAP in toluene, in the presence of triethylamine, under reflux, i.e. at about 100.degree. C., for 12 hours. Although the tetraphenyldinaphthyldiphosphine, i.e. the BINAP, and its reaction product withstand this treatment well, the same does not apply to the various other phosphines, which are more delicate. The interest of the present invention lies in the fact that very active catalysts based on complexes of Ru with phosphine ligands, which are more economic than those in the articles cited above, can be prepared industrially under milder conditions by a novel improved method.
In the method according
REFERENCES:
patent: 5021593 (1991-06-01), Nohira et al.
patent: 5118825 (1992-06-01), Wu
Ikariya et al., J. Chem. Soc., Chem. Commun., pp. 922-924 (1985).
Stephenson et al., J. Inorg. Nucl. Chem., vol. 28, pp. 945-956 (1966).
Noyori et al., J. Am. Chem. Soc., vol. 109, No. 19, pp. 5856-5858 (1987).
Kitamura et al., J. Am. Chem. Soc., vol. 110, No. 2, pp. 629-631 (1988).
Genet Jean-Pierre
Juge Sylvain
Mallart Sergio
Dees Jos,e G.
Nazario Porforio
Societe Nationale Elf Aquitaine
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