MXPA00008196A - Method for separating a diphosphine diastereoisomers - Google Patents

Abstract

The invention concerns a method for separating (d/l) and (meso) diastereoisomers of bis-[1-phospha- 2,3-diphenyl- 4,5-dimethylnorbornadiene]. The invention also concerns a method for preparing optically active diphosphines of bis- [1-phospha-2,3 -diphenyl-4,5 -dimethylnorbonadiene]. The bis- [1-phospha- 2,3-diphenyl-4,5 -dimethylnorbonadiene]diastereoisomers are separated by a method which consists in transforming the mixture of bis- [1-phospha- 2,3-diphenyl-4,5 -dimethylnorbonadiene]diastereoisomers into a mixture of the corresponding diphosphine dioxide or disulphide, then in separating the two diastereoisomers in the form of dioxide and disulphide.

Description

PROCEDURE FOR SEPARATION OF DIASTEREOISOMEROS OF A DIFOSFINA DESCRIPTION OF THE INVENTION The present invention relates to a process for separating diastereoisomers (d / 1) and (month or) from bis- [1-phospha-2,3-diphenyl-4,5-dimethylnorbornadiene]. The invention also relates to a process for the preparation of the optically active diphosphines of bis- [1-phospha-2,3-diphenyl-4,5-dimethylnorbornadiene]. It has been described by F. Mathey et al, in Bull. Soc. Chim. Fr. 129, pp. 1-8 (1992) the preparation of a diastereomer mixture of bis- [1-phospha-2, 3-diphenyl-4,5-dimethylnorbornadiene]. The starting product of the synthesis of these is 1-phenyl-3,4-dimethylphosphol (II) described by F. Mathey et al, in Síntesis, 1983, pp. 983. Begin by performing the preparation of 3, 3 ', 4, 4' -tetramethyl-1, 1 '-difosfol (IV). For this purpose, l-phenyl-3,4-dimethylphosphol (II) is reacted in tetrahydrofuran with metallic lithium according to the following reaction: (II) (III) Aluminum chloride is introduced at the end of the reaction to trap the phenyl-lithium produced in the course of the reaction. In a next step, the dimerization of (III) is carried out by diiod I2 in tetrahydrofuran. For more details on the preparation of (IV), one can resort to the article by F. Mathey et al, Organometallics, 1983, 2, 1234.

By heating to 140 ° C, the compound (IV) is rearranged in (V) which reacts with the diphenylacetolyl according to Diels-Adler, to give the bis- [1-phospha-2,3-diphenyl-, 5- dimethylnorbornadiene].

(SAW) A practical embodiment is given on page 6 of the publication by F. Mathey et al. in Bull. Soc. Chim. Fr. 129, pp. 1-8 (1992). However, the authors have obtained on page 3 right column, lines 7 and 8, a mixture of two diastereoisomers subsequently identified by the applicant as a meso (1 m) RS, SR - and a racemic (1 r) - RR, SS named respectively in the article, (13b) and 13a). The publication mentions the separation of two diastereoisomers by formation of a palladium (II) chelate. To do this, the separation of the mixture of diastereoisomers obtained is described, by reaction with PdCl2 (PhCN) 2 in the dichloroethane leading to (VI m) and (VI r), separation by chromatography on silica gel followed by an elution , and then a decomposition of the complex, carried out by NaCN.

The two diastereoisomers are then recovered separately, on the one hand the meso (1 m) and on the other hand the racemic (1 r).

The process described above allows a separation of diastereoisomers but it is difficult in the current state, usable on an industrial scale since the palladium complex is expensive. The object of the present invention is to provide a more economical method for separating diastereoisomers. It has been found that diastereoisomers (d / 1) and (me so) of the bis- [1- phospha-2, 3-diphenyl-4,5-dimethylnorbornadiene] can be separated according to a process which consists in transforming the mixture of diastereo diastereomers of the bis- [1-fos fa-2, 3-di phenyl-4,5-dimet i lnorbornadiene], in a mixture of diastereoisomers of corresponding diphosphine dioxide or disulfide, then in separating the two diastereoisomers in the form of dioxide or disulfide . According to a first variant of the invention, the separation of diastereomers of bis- [1-phospha-2, 3-diphenyl-4,5-dimethylnorbornadiene] obtained is obtained by subjecting the methacrylate of diastereomers of bis- [l-phospha-2, 3-diphenyl-4,5-dimethylnorbornadiene] to an oxidation reaction which converts them into bis- [1-phospha-2,3-di-phenyl-4,5-dimethylnorbornadiene dioxide] ] Another variant of the invention consists in effecting the separation of diastereomers of bis- [1-phospha-2, 3-diphenyl-4,5-dimethylnorbornadiene] disulphide obtained by reacting the diastereomer mixture of bis- [1-fos 2, 3-diphenyl-4,5-dimethylnorbornadiene] with sulfur, leading to a mixture of bis- [1-phospha-2,3-diphenyl-4,5-dimethylnorbornadiene] disulfide diastereomers].

Dioxides of diphosphines in the meso or racemic form Another object of the invention lies in the dioxides of bis- [1-phospha-2, 3-diphenyl-4,5-dimethylnorbornadiene] in the meso and racemic form, as well as the process for obtaining same. According to a first operation, the tereosis days are transformed in the form of oxide. These can be symbolized by the following formula: The diphosphine oxides of the formula (IX) are obtained by oxidation of two diastereoisomers of the formula (Im) e (Ir) with the aid of an oxidizing agent. Although any type of oxidizing agent can be used, a chemical oxidant, for example potassium permanganate or molecular oxygen or a gas containing it, it is preferred to resort to hydrogen peroxide, preferably in the form of an aqueous solution. The concentration of the hydrogen peroxide solution is advantageously between 10% and 35% by weight. The amount of oxidizing agent put into operation can vary greatly with the stoichiometric amount to an excess which represents for example 20 times the stoichiometry. An organic solvent is used, which solubilizes all the reagents. The solvent can be chosen from the aromatic, preferably aromatic, aliphatic, cycloaliphatic or aromatic hydrocarbons. The examples are given below. Among all these solvents, toluene and xylenes are preferred. The concentration of the diphosphine in the reaction solvent is preferably between 0.05 and 1 mol / liter and still more particularly between 0.05 and 0.2 mol / liter. The dissolved diastereomers are then contacted in general in a suitable solvent, in contact with the oxidizing agent.

The reaction is advantageously conducted between 50 ° C and 100 ° C. The duration of the reaction is generally between 30 minutes and 4 hours. The diphosphine oxides are recovered in the organic phase. The aqueous and organic phases are separated. A classical treatment of the phases is carried out. In this way, the aqueous phase is washed several times (from 1 to 3) by an organic solvent for extraction of diphosphine oxides, for example ethyl ether. All the organic phases are combined and washed with a brine (saturated sodium chloride solution), then a usual drying operation is carried out, preferably on a desiccant, for example sodium or magnesium sulfate. In a next step, the oxides are separated from the two diastereoisomers. The solvent is concentrated by evaporation and then the separation is carried out in a known manner [A. Bertheillier - Dunod Paris (1972)] by liquid chromatography on a column, preferably with a silica support.

The column is eluted with a mixture of suitable solvents. The solvents suitable for the separation are determined by means of simple operations carried out by the person skilled in the art, which consist in carrying out a chromatography on silica plate. The solvents are generally chosen from ethyl acetate, methanol, ethyl ether or mixtures thereof. Thus, depending on the case, diphosphine dioxide under the meso form (IXm) and diphosphine dioxide under the racemic form (IXr) are recovered in a variable order in the elution solvents.

Diphosphine disulphides under the meso racemic form Another object of the invention lies in the disulfides of bis- [1-phospha-2, 3-diphenyl-4,5-dimethylnorbornadiene] in the meso and racemic form, as well as the process for obtaining same. It has also been found that the diastereoisomers could be separated according to a process consisting in reacting with the sulfur, the mixture of diastereomers (Im) and (Ir), thus transforming them into diphosphine disulfide (IX'm) and (IX) 'r), then separating the diphosphine disulfides from the two diastereoisomers. According to a first operation, the diastereoisomers are transformed in the form of sulfur. These can be symbolized under the following formula: (IX ') In this way, the sulfur (S?) Is reacted with the mixture of two diastereoisomers under the meso (Im) form and under the racemic form (Ir) leading to a mixture of diphosphine disulfides, under the meso or racemic form. In general, the amount of sulfur put into operation defined in relation to each phosphorus atom varies from the stoichiometric amount to a slight excess of 10%. The reaction takes place at a temperature ranging from room temperature to about 100 ° C, preferably up to about 80 ° C, in a solvent of aromatic hydrocarbon type, and mainly toluene. In a next step, the mixture of shallow days is separated on a silica column, as described above. In this way, the diphosphine disulfide is recovered under the meso form (IX'ra) and the diphosphine disulfide under the racemic form (IX'r): (IX'm) DIFOSPHINES UNDER THE FORM OF A BIRTHDAY Another object of the present invention is the process for the preparation of optically active diphosphines of bis- [1- fos fa-2,3-di phenyl-, 5-dimethylnorbornadiene] which correspond to the following formulas: The invention thus provides a process for the preparation of diphosphines, chirals on phosphorus and non-racemisable.

A first variant for obtaining an optically active diphosphine of the formula (la) or (Ib) consists in carrying out the cleavage of the bis- [1-phospha-2, 3-diphenyl-4,5-dimethylnorbornadiene] dioxide under the form ( IXr), then separately carrying out the reduction of the enantiomers of bis- [1-phospha-2, 3-diphenyl-4, 5-dimethylnorbornadiene] obtained (IXa) or (IXb). Another variant of the invention consists in first carrying out the reduction of the bis- [l-phospha-2, 3-diphenyl-4,5-dimethyl-ilnorbornadiene] dioxide under the racemic form (IXr) in bis- [1-fos fa] 2, 3-diphenyl-4,5-dimethylnorbornadiene] under the racemic form (Ir), then in carrying out the cleavage of bis- [1-phospha-2,3-diphenyl-4,5-di-ethylnorbornadiene] in the racemic form (Go) in the enantiomers (la) and (Ib). Another variant of the invention consists in effecting the splitting of the racemic disulfide mixture of bis- [1-phospha-2, 3-diphenyl-4,5-dimethylnorbornadiene] (IX 'r) then in reducing the disulfide enantiomers of bis - [1-fos fa-2, 3-diphenyl-4, 5-dimet ilnorbornadiene] (IX'a) and (IX'b) in the enantiomers of bis- [1-phospha-2, 3-diphenyl-4, 5-dimethylnorbornadiene] (la) and (Ib).

Another variant consists in reducing the racemic mixture of bis- [1-phospha-2,3-diphenyl-4,5-dimethylnorbornadiene] (IX 'r) disulfide in the racemic mixture of bis- [1-phospha-2, 3 -diphenyl-4, 5-dimethylnorbornadiene] (Ir) then in effecting the splitting of the racemic mixture of bis- [l-phospha-2, 3-diphenyl-4,5-dimethylnorbornadiene] into the enantiomers (la) and (Ib) ). Another variant of the invention is to transform the racemic disulfide mixture of bis- [1-phospha-2, 3-diphenyl-4,5-dimethylnorbornadiene] (IX'r) into the racemic mixture of bis- [1-phosphate] -2, 3-diphenyl-4,5-dimethylnorbornadiene] (IXr) and then obtain the optically active diphosphines (la) and (b) according to the modalities described above.

Oxide enantiomers According to a first embodiment of the invention, the splitting of the racemic mixture of bis- [l-phospha-2, 3-diphenyl-4,5-dimeti-Inorbor-eigene] dioxide (IXr) is carried out.

The resolution can be effected by separation of the two enantiomers, by chiral liquid chromatography. A chiral column is used, for example, Chiralcel OJ® [modified cellulose ester column (see reference cited below, page 262)], Chirose Cl or C3® (cross-linked polymer grafted on silica), Chirosebond Cl or C3® (graft) of chiral polymer of polyholoside type on spherical silica of 5 μm - 100 Á) and the eluting solvents can be mainly a water / acetonitrile mixture. The start-up of the separation is carried out according to the classical techniques of the domain under consideration (see Stéréochimie des composés chimiques, Ernest L. Eliel et al, Technique et Documentation 1996, pp. 249-250). In this way, two enantiomers are obtained: (IXb) In a subsequent step, the dioxides of optically active bis- [1-phospha-2, 3-diphenyl-4, 5-dimethylnorbornadiene] of the formula (IXa) or (IXb) are reduced. It can be referred to the description of the reduction operation given below. Another variant consists first in effecting the reduction of the bis- [1-phospha-2,3-diphenyl-4,5-dimethylnorbornadiene] dioxide under the racemic form and then in effecting the splitting of the diphosphine under the racemic form obtained. The reduction can be carried out with a reducing agent such as, for example, trichlorosilane, hexachlorodisilazane, phenyltrisilane, a hydride mainly LiAlH4 or NaBH4. The amount of reducing agent put into operation can vary greatly depending on the stoichiometric amount to an excess which represents for example 20 times the stoichiometry. When a reducing agent is used which leads to the release of a halogenated acid, for example trichlorosilane or hexachlorodisilazane, a base is added, preferably an amine in order to trap the liberated halogenated acid (hydrochloric acid).

As more specific examples, mention may be made of picolines, pyridine, 2-ethylpyridine, 4-ethylpyridine, 2-methylpyridine, 4-methylpyridine, 2,4-dimethylpyridine, imidazole, 1-methylimidazole, TMEDA (tetramethylenediamine), N-methylpyrrolidine, 4-methylmorpholine, triethylamine, DBU (1,8-diazabicyclo [5.4; 0.] 7-undecene). The amount of amine is at least equal to the amount necessary to trap the halogenated acid released, and is more frequently in excess which can go up to 3 times the stoichiometric amount. The reaction is conducted in an organic solvent which solubilizes all the reactants. The solvent can be chosen from aliphatic, aromatic, halogenated or non-halogenated hydrocarbons. Among all these solvents, toluene and dichloromethane are preferred. The concentration of the diphosphine in the reaction solvent is preferably between 0.05 and 1 mol / liter and still more particularly between 0.05 and 0.2 mol / liter. From a practical point of view, more frequently, in a mixture of solvents, and in the presence of an amine, the racemic compound is added, in the form of oxides, then the reducing agent. The reaction is advantageously conducted between 50 ° C and 100 ° C. The duration of the reaction is generally between 30 minutes and 4 hours. The racemic mixture is in the organic phase. It is always necessary to perform a basic treatment in the case where the reducing agent is in excess in order to destroy it. After cooling, a base is added immediately, preferably soda, potash or sodium carbonate, until obtaining a basic pH (pH of at least 8). Preference is given to a basic aqueous solution, preferably a soda solution having a concentration of 10% to 30%. The aqueous and organic phases are separated. The enantiomers of the diphosphines are recovered in the organic phase which is subjected to the conventional treatment described above, extraction with solvent, washing with brine and optionally drying. A racemic mixture of two enantiomers is obtained which can be separated quickly.

The splitting of the racemic mixture of bis- [1-phospha-2, 3-diphenyl-4,5-dimethylnorbornadiene] can be carried out according to the procedure described in patents FR No. 94/15757 and PCT / FR95 / 01716, by reacting the racemic mixture with a palladium and / or platinum complex, as a chiral auxiliary which thus forms the diastereoisomeric complexes, then unfolding said optically pure complexes. You can resort to a palladium complex.

This type of chiral auxiliary is described extensively in the literature, mainly by Sei Ots uka et al, in Journal of the American Chemical Society 93, p. 4301 (1971). It is also possible to resort to a platinum complex and reference can be made more particularly to the works of A. C. Cope [Journal of the American Chemical Society 9_0_, p. 909 (1968)]. The chiral complex put into operation responds more particularly to the general formula (VII): in said formula: M represents palladium and / or platinum, R-,, R2, R_ and R_ represent a hydrogen atom or an alkyl radical having 1 to 10 carbon atoms or a cycloalkyl radical having from 3 to 10 carbon atoms, Rj and Rj are different and at least one of the two represents a hydrogen atom, R has the meaning given for Ri, R2, R3 and R., X represents a halogen atom, N is a number from 0 to 4, - When n is greater than 1, two R radicals and the 2 successive atoms of the benzene cycle can form between them, a cycle that has 5 to 7 carbon atoms. More preferably, the complex put into operation responds to the formula previously indicated in which Ri, R2, R3 and R_ represent a hydrogen atom or a methyl radical, X represents a chlorine atom and n is equal to 0. When n is equal to 2, two R radicals form a benzene ring. As more specific examples of palladium complexes suitable for the present invention, obtained indifferently from (R) - (+) or (S) - (-) -N, N-dimet i 1 phení let ilamina, can be mentioned: The amount of the complex of the aforementioned metals, expressed in metal, is generally 0.5 to 1 metal atom per atom of the forum. An organic solvent is used, which solubilizes all the reagents. The solvent must be inert against diphosphine.

As non-limiting examples of solvents that suit the process of the invention, there may be mentioned: aliphatic hydrocarbons and more particularly paraffins, mainly pentane, hexane, heptane, octane, isooctane, nonane, decane, undecane, tetradecane, petroleum ether and cyclohexane; aromatic hydrocarbons mainly such as benzene, toluene, xylenes, ethylbenzene, diethylbenzenes, trimethylbenzenes, eumeno, pseudocumene, petroleum cuts consisting of a mixture of alkylbenzenes, mainly Solvesso® type cuts, aliphatic or aromatic halogenated hydrocarbons, and can be mentioned : mainly perchlorinated hydrocarbons such as trichloromethane, tetrachlorethylene; partially chlorinated hydrocarbons such as dichloromethane, dichloroethane, tetrachloroethane, trichlorethylene, 1-chlorobutane, 1,2-dichlorobutane; monochlorobenzene, 1,2-dichlorobenzene, 1,3-dichlorobenzene, 1,4-dichlorobenzene or mixtures of different chlorobenzenes. Among all these solvents, benzene and toluene are preferred.

The concentration of the diphosphine in the reaction solvent is preferably between 0.05 and 1 mol / liter, and still more particularly between 0.05 and 0.2 mol / liter. The separation is advantageously carried out at room temperature in general between 15 ° C and 25 ° C. This preferably takes place under a controlled atmosphere of inert gases. An atmosphere of rare gases, preferably argon, can be established, but it is more economical to resort to nitrogen. A mixture of palladium or platinum and corresponding diphosphine complexes is obtained in each enantiomer. This responds more particularly to the following formulas: (Villa) (VIII b) in these formulas, M represents palladium or platinum, X a halogen atom, preferably chlorine, and A symbolizes the residue of a chiral metal complex that responds to one of the formulas (VII) and preferably (VII '). In a next step, the two pure enantiomers are recovered. The solvent is concentrated by evaporation and then the separation is carried out in a known manner [A. Bertheillier - Dunod Paris (1972)] by liquid chromatography on a column, preferably with a silica support. The column is eluted with a mixture of suitable solvents, preferably a toluene / ethyl acetate mixture preferably including, 80% by volume of toluene and 20% by volume of ethyl acetate. The two isolated, pure enantiomers are recovered in the form of two diastereomeric complexes having the following characteristics: RMN31P = d (CH2Cl2) = 55.9 ppm RMN31P = 6 (CH2C12) = 53.6 ppm The two pure diphosphine enantiomers are recovered by carrying out the decomposition of complexes. For this purpose, a hydrocyanic acid salt is preferably used, preferably an alkali salt and still more preferably sodium; Said salt is put into solution in the minimum amount of water needed. The complexes are solubilized in an organic solvent such as, for example, dichloromethane, then, under agitation, the hydrocyanic acid salt put into operation in general in excess which represents 2 to 5 moles per metal atom is introduced. The operation is also conducted under a controlled atmosphere and at room temperature. The enantiomer is recovered in the organic phase which is separated off, washed with water and dried, for example over sodium sulfate. The two enantiomers of pure, isolated bis- [1-phospha-2, 3-diphenyl-4, 5-dimethylnorbornadiene] are obtained which correspond to the formulas [(Ia- (S, S) (+)] and [( Ib) - (R, R) (-)] previously indicated, whose characteristics are the following: RMN31P = d (CDCl3) = 13.2 ppm- [a] D = + 231 ° (c = 1, C6D6).

RMNJiP = d (CDCl3: 13.2 ppm- [a] -198 (c = 1, C5D6). (with a [] D determined for a concentration of 10 mg / ml and at room temperature).

Enantiomers via sulfide When the optically active diphosphines are prepared according to a sulfide route, the splitting of the racemic disulfide mixture of bis- [1-phospha-2,3-diphenyl-4,5-dimethylnorbornadiem] (IX 'r) is carried out. on a chiral column, allowing the disulfides of bis- [1-phospha-2, 3-diphenyl-4,5-dimethylnorbornadiene] optically active (IX'a) and (IX'b) to be obtained, then they are reduced in diphosphines leading thus to the optically active diphosphines (la) and (Ib). The reduction of diphosphine disulfides is carried out by reaction with a phosphorous reagent of the type PBu3 or P (CH2CH2CN) 3; The reaction is conducted in an organic solvent medium, for example an aromatic hydrocarbon, preferably toluene. The reaction is generally carried out at the reflux temperature of the reaction solvent.

In this way, two enantiomers are obtained Another variant consists of reducing the racemic mixture of disulfides of bis- [1-phospha-2,3-diphenyl-4,5-dimet and Inorbornadiene] (IX'r) in racemic mixture of bis- [1-phospha-2, 3-diphenyl-4,5-dimethylnorbornadiene] (Ir) then in effecting the splitting of the racemic mixture of bis- [l-phospha-2,3-diphenyl-4,5-dimethylnornambediene] into optically active phosphines (la) and (Ib) The reduction of the racemic mixture of diphosphine disulfides is conducted in a manner such as is indicated for the optically active diphosphine disulfides. Finally, another variant of the invention consists of transforming the racemic mixture of bis- [1-phospha-2,3-diphenyl-4,5-dimethylnorbornadiene] disulfides into the racemic mixture of bis- [1-phospha-2] dioxides , 3-diphenyl-4,5-dimethylnorbornadiene] after obtaining the optically active diphosphines (la) and (Ib) according to the aforementioned pathways. It is possible to convert the diphosphine disulfides into diphosphine dioxides by any appropriate means, in particular by reacting the diphosphine disulfides with the cyclohexene oxide, in trifluoroacetic acid and in organic solvent medium, in particular in a halogenated aliphatic hydrocarbon , preferably, methylene chloride. The racemic mixture (IXr) which is treated as mentioned above is obtained. The optically active diphosphines obtained according to the process of the invention have a more particular interest in organic chemistry, in the asymmetric synthesis methods. The optically active diphosphines according to the invention can be used for the preparation of metal complexes that allow the asymmetric hydrogenation of unsaturated derivatives.

More particularly, these can be used to perform the asymmetric hydrogenation reactions. The optically active diphosphines according to the invention can be used for the preparation of metal complexes, which allow the asymmetric hydrogenation, mainly of α, β-unsaturated carboxylic acids and / or derivatives and ketonic compounds. The optically active diphosphines of the formula (la) or (Ib) serve as ligands in the formation of complex coordinates with transition metals. As examples of transition metals capable of forming complexes, mention may be made, in particular, of metals such as rhodium, ruthenium, rhenium, iridium, cobalt, nickel, platinum, and palladium. Among the metals indicated above, rhodium, ruthenium and iridium are preferred. Specific examples of said complexes of the present invention are given below, without limitation. In the formulas, (P * P) represents the diphosphine of the formula (la) or (Ib).

The rhodium and iridium complexes can be represented by the following formulas: [M L2 (P * P)] Y (XlVa) [M L2 (P * P)] Y (XlVb) in these formulas: (P * P) represents in the formula (XlVa) the diphosphine of formula (la) and in the formula (XlVb) the diphosphine of the formula (Ib), - M represents rhodium or iridium, - Y represents a anionic coordination ligand, L represents a neutral ligand. The preferred complexes of rhodium or iridium correspond to the formula (XlVa) or (XVIb) in which: - L represents an olefin having 2 to 12 carbon atoms and two ligands L can be linked together to form a chain polyunsaturated, linear or cyclic hydrocarbon; L preferably represents 1, 5-cyclooctadiene, norbornadiene, or ethylene. Y represents an anion PF6-, PC16-, BF-, BC14-, SbF6, SbCl6-, BPh4-, C104-, CN ", CF3S03", halogen preferably, Cl ", or Br", a 1,3- anion dicetonate, alkylcarboxylate, haloalkylcarboxylate with a lower alkyl radical, a phenylcarboxylate anion or phenolate wherein the benzene ring may be substituted by lower alkyl radicals and / or halogen atoms. By lower alkyl radicals is meant in general a linear or branched alkyl radical having from 1 to 4 carbon atoms. Other iridium complexes can be represented by the formulas: [Go L (P * P)] Y (XVa) [Go L (P * P)] Y (XVb) in these formulas, (P * P), L and Y have the given meanings for the formulas (XlVa) and (XlVb). As regards the ruthenium complexes, they preferentially respond to the following formulas: [RuY? Y2 (P * P)] (xvi; [RuY? Y2 (P * P)] (XVIb) in said formulas: - (P * P) represents in formula (XVIa) the diphosphine of formula (la) and in the formula (XVIb) the diphosphine of the formula (Ib), - Yi and Y2, identical or different, preferably represent an anion PF6 ~, PClβ ", BF4", BC14"," SbF6 ~, SbCl6", BPh4", C104 ~, CF3S03", a halogen atom, more particularly, chlorine or bromine or a carboxylate anion, preferably acetate, trifluoroacetate. Other ruthenium complexes susceptible to be put into operation in the process of the invention respond to the following formulas: [RuYiAr (P * P) Y2]; XVIc) [RuYiAr (P * P) Y2] (XVId) in said formulas: - (P * P) represents in the formula (XVIc) the diphosphine of the formula (la) and in the formula (XVId) the diphosphine of the formula (Ib), Ar represents benzene, p-methylisopropylbenzene, hexamethylbenzene, - Yi represents a halogen atom, preferably chlorine or bromine, Y2 represents an anion of preference, an anion PF6 ~, PC16", BF4", BC14 ~, SbF6", SbCl6", BPh4", It is also possible to put in operation in the process of the invention the palladium and platinum-based complexes As more specific examples of said complexes, there may be mentioned among others PdCl2 (P * P) and PtCl2 (P * P) in which (P * P) P) represents the diphosphine of the formula (la) or (Ib) .The complexes comprising the above-mentioned diphosphine and the transition metal can be prepared according to the known procedures described in the literature.For the preparation of ruthenium complexes , we can refer mainly to the publication of J.- P. Genét [Acros Organics Acta, 1_, Nr. 1, pp. 1-8 (1994)] and for the other complexes, to the article by Schrock R. and Osborn J.A. [Journal of the American Chemical Society, 9J3_, pp. 2397 (1971)]. These can be prepared in particular by reaction of the diphosphine of the formula (la) or (Ib) with the transition metal compound, in an appropriate organic solvent. The reaction is conducted at a temperature between room temperature (15 to 25 ° C) and the reflux temperature of the reaction solvent. As examples of organic solvents, there may be mentioned, among others, aliphatic hydrocarbons, halogenated or not and more particularly, hexane, heptane, isooctane, decane, benzene, toluene, methylene chloride, chloroform; solvents of the ether or acetone type and mainly diethyl ether, tetrahydrofuran, acetone, methyl ethyl ketone; the alcohol type solvents, preferably methanol or ethanol. The metal complexes according to the invention, recovered according to the classical techniques (filtration or crystallization) are used in the asymmetric hydrogenation reactions of the substrates indicated above in PCT / FR95 / 01716 and PCT / FR97 / 01154 applications. α, β-unsaturated carboxylic acid and / or its derivatives correspond more particularly to formula (X): in said formula (X): R, R2, R3 and R represent a hydrogen atom or any hydrocarbon group, in the measure where: - if Ri is different from R2 and different from a hydrogen atom, then R3 can be any group hydrocarbon or functional designated by R, if Ri or R2 represent a hydrogen atom and if Ri is different from R2, then R3 is different from a hydrogen atom and different from -COOR4, - if Ri is identical to R2 and represents any group hydrocarbon or functional designated by R, then R3 is different from -CH- (i.) 2 and different from -COOR4. one of the groups Ri, R2 and R3 may represent a functional group. The α, β-unsaturated and / or derivatized carboxylic acid preferably corresponds to the formula (X) in which the identical or different Ri to R radicals represent an optionally substituted hydrocarbon radical having from 1 to 20 carbon atoms, which can be an acyclic radical saturated or unsaturated, linear or branched; a carbocyclic or heterocyclic saturated, unsaturated or aromatic, monocyclic or polycyclic radical; a saturated or unsaturated aliphatic radical, linear or branched, carrying a cyclic substituent. As preferred examples of carboxylic acids put into operation, there may be mentioned a substituted acrylic acid, precursor of an amino acid, itaconic acid and / or derivative, an arylpropionic acid and / or derivative. Other substrates susceptible to being hydrogenated are ketones and derivatives, mainly simple ketones, ketones functionalized at a, b,? or d and derivatives (keto acids, ketoesters, thioacids, thioesters), the diketone compounds have a carbonyl group in position a, β,? or d, in relation to a first carbonyl group. The following examples, given in a non-limiting manner, illustrate the present invention.

EXAMPLES EXAMPLE 1 Preparation of diphosphine dioxides In a 250 ml ball flask equipped with a magnetic bar, 4 g (6.92 mmol) of a diastereomer mixture of bis- [1-phospha-2,3-diphenyl-4,5] are dissolved in 100 ml of toluene. -dimethylnorbornadiene] under the form meso (Im) and racemic d / 1 (Ir) in the respective proportions of 25 (d / 1) and 75 (meso). This mixture is obtained according to the mode of operation given in the application PCT / FR95 / 01716. The solution obtained is heated to 80 ° C and 9 ml of an aqueous solution of hydrogen peroxide at 15% by weight are added. Stirring and temperature are maintained for 30 minutes. After cooling, 100 ml of water are added and the two phases are allowed to settle. The organic phase is washed twice with water, the aqueous phase twice with dichloromethane.

The different organic fractions are combined, which are then dried over sodium sulphate. After evaporation, the residue is chromatographed on silica gel (0.060 rom granulometry) to separate these two products with the aid of an eluent. The meso is recovered first, eluting with the help of ethyl acetate. The racemate is recovered in the second place, with a mixture of ethyl acetate / methanol 80/20 by volume. The two oxides are purified separately by precipitation in ethyl acetate. 2.8 g of meso and 1.2 g of racemic (94%) are obtained. RMN31P = d (CDCl3) = 48.18 ppm - minor isomer corresponding to meso. RMN31P = d (CDCl3) = 47.77 ppm - minor isomer corresponding to racemic.

EXAMPLE 2 Reduction of diphosphine dioxides in diphosphines Under an argon atmosphere, in a 100 ml ball flask equipped with a magnetic bar, it is dissolved in 40 ml of a mixture of 1,2-dichloroethane / toluene 1/1 by volume, 1 g (1.96 mmol) of the racemic mixture (d / 1) obtained according to example 1 and 2 ml of pyridine are added. A solution of 2 ml of HSiCl3 (19.8 mmol, d = 1342) in 2 ml of toluene is added dropwise in 10 minutes at room temperature. It is heated at 80 ° C for 30 minutes. When the reaction is finished, the reaction medium is cooled. An aqueous 30% sodium hydroxide solution is then added until the solution is alkaline. Diphosphine (d / 1) is extracted in a conventional manner by decanting, washing with water from the organic phase and washing with ether from the aqueous phase. The different organic fractions are combined and then dried over sodium sulfate. After evaporation of the solvent, the residue containing the phosphine is rapidly subjected to chromatography on silica gel eluting with dichloromethane. The phosphine is then recovered in the form of a white powder after evaporation of the chromatography solvent. 1.0 g are recovered corresponding to a yield of 88%.

EXAMPLE 3 Preparation of diphosphine disulfides 250 ml of toluene, 2.9 g (5 mmol) of a mixture of diastereomers of bis- [1-phospha-2,3-diphenyl-4, 5 are dissolved in a 250 ml ball flask equipped with a magnetic rod. dimethylnorbornadiene] in the form meso (Im) and racemic d / 1 (Ir) in the respective proportions of 25 (d / 1) and 75 (meso). This mixture is obtained according to the mode of operation given in the application PCT / FR95 / 01716. The solution obtained is heated at 80 ° C for 5 hours. After evaporation of the toluene, the residue is chromatographed on silica gel to separate these two products with the aid of an eluent, dichloromethane.

The meso recovers first. The racemate recovers in second place. 2.2 g of meso (74%) and 0.7 g of racemic (22%) are obtained. RMN31P = d (CDCl3) = 51.6 and 48.18 ppm - J (A-B) = 9.7 Hz. RMN31P = d (CDCl3) = 49.6 ppm.

EXAMPLE 4 Oxidation of diphosphine disulfides in diphosphine dioxides in racemic form (IXr).

Under a flow of argon, 0.7 g (1.1 mmol) of the diastereomer d / 1, obtained previously in 10 ml of methylene chloride, is added in solution, then 0.5 g of CF3COOH (4.4 mmol) and 0.4 g of cyclohexene oxide are added ( 4.4 mmol). The mixture is heated at reflux of the solvent for 30 minutes. The excess acid is neutralized by a sodium carbonate solution and then the aqueous phase is extracted with ether. The organic phases are combined and dried over anhydrous magnesium sulfate. The solvent evaporates.

The residue is purified by chromatography on silica gel with a mixture of ethyl acetate / methanol (90/10). The racemic diphosphine dioxide is obtained. The two enantiomers are then separated after the reduction of racemic diphosphine dioxide according to the same mode of operation of example 2.

Claims (28)

RE I INDICATIONS

1. Process for separating diastereoisomers (d / 1) and (meso) from bis- [1-fos fa-2,3-diphenyl-4,5-dimethylnorbornadiene] characterized in that it consists of transforming the diastereomer mixture of bis- [1-] fos fa-2, 3-diphenyl-4,5-dimethylnorbornadiene], in a mixture of diastereoisomers of disulfide or of corresponding diphosphine dioxide, then in separating the two diastereomers in the form of dioxide or disulfide.

2. Process according to claim 1, characterized in that the diastereomers of bis- [1-phospha-2, 3-diphenyl-4,5-dimethylnorbornadiene] obtained by subjecting the diastereomer mixture of bis- [1] are separated. -phospha-2, 3-diphenyl-4,5-di-ethylnorbornadiene] to an oxidation reaction which thus transforms them into bis- [l-phospha-2, 3-diphenyl-4,5-dimethylnorbornadiene] dioxide].

3. Process according to claim 2, characterized in that it consists of oxidizing the diastereomer mixture of bis- [l-phospha-2, 3-di phenyl-, 5-dimethylnorbornadiene], with the help of an oxidizing agent, preferably the hydrogen peroxide.

4. Method according to any of claims 2 and 3, characterized in that the two diastereomers (IXm) and (IXr) are separated by liquid chromatography on a column, preferably on a silica support, making it possible to obtain on the one hand diphosphine dioxide in the meso form (IX) and diphosphine dioxide under the racemic form (IXr).

5. Method of preparing an optically active diphosphine of the formula (Ia) or (Ib): (Ib) - (R, R) - (-) from the tereoisomer dias (Ixr) obtained according to any of claims 1 to 4, characterized in that the fact consists in: carrying out the splitting of the diphosphine dioxide under the racemic form (IXr), then separately carrying out the reduction of the enantiomers (IXa) or (IXb) of the diphosphine dioxide.

6. Method according to claim 5, characterized in that the cleavage of (IXr) is carried out by chiral liquid chromatography, on Chiralcel OJ®, Chirose Cl or C3®, Chirosebond Cl or C3® column.

7. Method of preparing an optically active diphosphine of the formula (Ia) or (Ib), starting from the diastereomer (IXr) obtained according to any of claims 1 to 4, characterized in that it consists in: carrying out the reduction of diphosphine dioxide under the racemic form (IXr), leading to the diphosphine under the racemic form (Go), in effecting the splitting of diphosphine under the racemic form (Ir).

8. Process according to any of claims 5 and 7, characterized in that the reduction is effected by trichlorosilane, hexachlorodisilazane, phenyltrisilane, a hydride mainly LiAlH or NaBH4.

9. Process according to claim 8, characterized in that a base is added, preferably a tertiary amine and, more preferably, a picoline, pyridine, 2-ethylpyridine, 4-ethylpyridine, 2-methylpyridine, 4-methylpyridine, 2,6- dimethylpyridine, imidazole, 1-ethylimidazole, TMEDA (tetramethylenediamine), N-methylpyrrolidine, 4-methylmorpholine, triethylamine, DBU (1,8-diazabicyclo [5.4; 0.] 7-undecene).

10. Process according to claim 7, characterized in that it consists in effecting the splitting of the racemic mixture (Ir) of bis- [l-phospha-2, 3-diphenyl-4,5-dimethylnorbornadiene] by reacting it with a palladium complex and / or platinum as a chiral auxiliary, in an organic solvent thus forming diastereoisomeric complexes, then in unfolding said optically pure complexes.

11. Method according to claim 10, characterized in that the chiral auxiliary corresponds to the general formula (VII): in said formula: M represents palladium and / or platinum, Ri. R2. : and R. represent a hydrogen atom or an alkyl radical having from 1 to 10 carbon atoms or a cycloalkyl radical having from 3 to 10 carbon atoms, R3 and R. are different and at least one of the two represents a hydrogen atom, R has the given meaning for Ri, R2, R3 and R., - X represents a halogen atom, - n is a number from 0 to 4, - when n is greater than 1, two radicals R and the 2 successive atoms of the benzene cycle can form between them, a cycle that has from 5 to 7 carbon atoms.

12. Process according to any of claims 10 and 11, characterized in that the chiral auxiliary corresponds to the general formula (VII) in which Ri, R2, R3 and R4 represent a hydrogen atom or a methyl radical, X represents a chlorine atom and n equals 0.

13. Process according to any of claims 10 to 12, characterized in that the chiral auxiliary corresponds to the general formula (VII) in which Ri, R2, R3 and 4 represent a hydrogen atom or a methyl radical, X represents a chlorine atom and when n equals 2, two R radicals form a benzene ring.

14. Method according to any of claims 10 to 13, characterized in that the chiral auxiliary corresponds to the general formula (VII '):

15. Process according to any of claims 10 to 14, characterized in that the separation of the two enantiomers is effected by liquid chromatography on a column, preferably with a silica support.

16. The method according to claim 10, wherein the two enantiomers of the pure diphosphines are recovered by effecting the solubilization of the complexes in an organic solvent, such as, for example, dichloromethane, then the decomposition of the complexes with the aid of a hydrocyanic acid salt, preferably an alkali salt and still more preferably sodium.

17. Process according to claim 1, characterized in that it consists in effecting the separation of the diastereoisomers of bis- [1-phospha-2, 3-diphenyl-4,5-dimethylnorbornadiene] obtained by reacting the diastereomer mixture of bis- [1-phospha-2, 3-diphenyl-4,5-dimethylnorbornadiene] with sulfur, leading to a mixture of diastereomers of bis- [1-phospha-2,3-diphenyl-4,5-dimethylnorbornadiene disulfide] ]

18. Process for the preparation of an optically active diphosphine of the formula (la) or (Ib) from the tereoisomeric dias (IX'r) obtained according to claim 17, characterized in that it consists of effecting the splitting of the mixture racemic of diphosphine disulfides (IX 'r), preferably on a chiral column and then in reducing the enantiomers of diphosphine disulfides (IX'a) and (IX'b) in enantiomers of diphosphines (la) and (Ib).

19. Process for the preparation of an optically active diphosphine of the formula (la) or (Ib) from the diastereomer (IX'r) obtained according to claim 17, characterized in that it consists of reducing the racemic mixture of disulfides of diphosphines (IX'r) in racemic mixture of diphosphines (Ir) and then in carrying out the splitting of the racemic mixture of diphosphines into enantiomers (la) and (Ib).

20. Process according to any of claims 18 and 19, characterized in that the reduction of diphosphine disulfides is carried out by reaction with a phosphorous reagent of the type PBu3 or P (CH2CH2CN) 3.

21. Method of preparing an optically active diphosphine of the formula (Ia) or (Ib) from the diastereomer (IX 'r) obtained according to claim 17, characterized in that it consists of transforming the racemic mixture of diphosphine disulfides (IX' r) into racemic mixture of diphosphine dioxides (IXr) ) and then to obtain the optically active diphosphines (la) and (b) according to any of claims 2 to 16.

22. Process according to claim 21, characterized in that the conversion of the diphosphine disulfides, into diphosphine dioxides, is effected by reaction of the diphosphine disulfides with the cyclohexene oxide, in trifluoroacetic acid and in organic solvent medium .

23. The dioxide or disulfide of bis- [l-phospha-2, 3-diphenyl-, 5-dimethylnorbornadiene] which responds to the following formulas:

24. The diphosphine dioxide of bis- [l-phospha-2,3-di-phenyl-1,4- dimethylnorbromadiene] under the optically active form which corresponds to the following formulas: and under the meso form (IXm) and under the racemic form

25. The disulfide of bis- [1-fos fa-2,3-di phenyl-, 5-dimet i lnorbornadiene] under the optically active form which responds to the following formulas: I'm going to fo rma me under the racemic form

26. The use of an optically active diphosphine (la) or (Ib) obtained according to the process described in any of claims 1 to 22, for the preparation of coordinated metal catalytic complexes to selectively perform asymmetric syntheses in organic chemistry.

27. The use of an optically active diphosphine (la) or (Ib) obtained in accordance with the process described in any of claims 1 to 22, for the preparation of coordinated metal catalytic complexes to selectively perform an asymmetric hydrogenation.

28. The use according to claim 27, characterized in that the asymmetric hydrogenation of a α, β-unsaturated carboxylic acid and / or its derivatives or of a ketone and / or its derivatives is carried out.