WO2008080833A1

WO2008080833A1 - Method of preparation of a primary phosphine

Info

Publication number: WO2008080833A1
Application number: PCT/EP2007/064132
Authority: WO
Inventors: Mikaël BERTHOD; Marc Lemaire; Alain Favre-Reguillon; Gérard Mignani
Original assignee: Rhodia Operations; Centre National De La Recherche Scientifique
Priority date: 2006-12-21
Filing date: 2007-12-18
Publication date: 2008-07-10
Also published as: FR2910474A1; FR2910474B1

Abstract

A novel preparation method for a primary phosphine by reduction of the corresponding phosphonate. The reduction method according to the invention is characterized in that it comprises contacting the substrate having at least one phosphonate group, with a siloxane-type compound associated to a metallic and/or metalloidic element-based catalyst chosen from the groups (NIA), (IVA), (VA), (VIA), (VIIA), (VIII), (IB), (MB), (NIB), (IVB), (VB) of the elements of the periodic table.

Description

PROCESS FOR PREPARING PRIMARY PHOSPHINE

The present invention relates to a new process for the preparation of a primary phosphine.

More specifically, the invention relates to a process for preparing a primary phosphine by reducing the corresponding phosphonate.

There are only a few synthetic routes described in the literature allowing access to a primary phosphine.

Thus, Evan P. Kyba et al [Organometallics 2, 1877-1879 (1983)] have described the preparation of 1,2-bis (phosphino) benzene by reduction of 1,2-bis (dimethoxyphosphoryl) benzene with the aid of a reagent derived from trimethylsilyl chloride and lithium aluminum hydride in THF. However, the reagent LiAIH ₄ is not easy to handle because dangerous.

Another system HSiR ₃ / B (C ₆ F ₅ ) 3 has been described by Jean-Marc Denis et al [Tetrahedron Letters 43, 5569-5571 (2002)] but its implementation on an industrial scale is not possible because too expensive.

The object of the present invention is to provide a method which overcomes the aforementioned drawbacks.

It has now been found and this is the subject of the present invention a process for preparing a primary phosphine from the corresponding phosphonate characterized in that it comprises placing the substrate comprising at least one group phosphonate, in the presence of a siloxane-type compound corresponding to the following formula (I) associated with a catalyst based on a metallic and / or metalloidal element chosen from (NIA), (IVA), (VA) groups, (VIA), (VIIA), (VIII), (IB), (MB), (NIB), (IVB), (VB) of the periodic table of elements:

Ri R ₂ ^R 5 ^R i

R - Si O - (- Si - O) ^ (- Si - O) ^ Si - R ₃

R ₁ R ₄ Re R _{1 (|)} in said formula:

- R ₁ , R ₂ , R 5, R _Θ , identical or different, represent an alkyl, cycloalkyl or aryl group,

R3 represents a hydrogen atom or an alkyl, cycloalkyl or aryl group, R ₄ represents a hydrogen atom,

x is a number ranging from 0 to 50,

y is a number ranging from 0 to 50,

- x + y is at most equal to 100. - if x = 0 and y = 0, then R3 represents a hydrogen atom,

if x and y ≠ 0, then R ₃ represents an alkyl, cycloalkyl or aryl group,

if x = 0 and y ≠ 0, then R3 represents a hydrogen atom,

if x ≠ 0 and y = 0, then R ₃ represents an alkyl, cycloalkyl or aryl group.

In the context of the invention, the term "alkyl", a linear or branched hydrocarbon chain having 1 to 10 carbon atoms and preferably 1 to 4 carbon atoms.

Examples of preferred alkyl groups include methyl, ethyl, propyl, isopropyl, butyl, isobutyl and t-butyl.

By "cycloalkyl" is meant a cyclic, monocyclic hydrocarbon group comprising 5 or 6 carbon atoms, preferably a cyclopentyl or cyclohexyl group.

By "aryl" is meant an aromatic mono- or polycyclic group, preferably mono- or bicyclic comprising from 6 to 12 carbon atoms, preferably phenyl.

The siloxane compounds which are used in the process of the invention preferentially correspond to the formula (I) in which R ₁ , R 2, R ₃ , R ₅ and Re are identical and represent an alkyl group having from 1 to 4 carbon atoms, preferably a methyl group: R ₄ is a hydrogen atom.

The preferred siloxane compounds have formula (I) wherein y is 0.

As regards x, it is preferably between 0 and 50 and even more preferably equal to 0 or between 45 and 50. Among the compounds of formula (I), those which are preferred are the following:

H- Si O Si -H

| I

CH ₃ CH ₃ denominated by the abbreviation TMDS, tetramethyldisiloxane. or

with x between 45 and 50 and denoted by the abbreviation PMHS, methylhydrogenpolysiloxane.

Examples of polysiloxanes which may be used in the process of the invention are also given.

with x between 10 and 15

CH. H CH, CH,

H ₃ C- Si -O - (- Si - θ) ^ (- Si - θ} ^ - Si -CH

CH. CH. CH. CH. with x + y ranging from 10 to 100 and preferably equal to 20 and y / x ranging from 1 to 10, preferably equal to 5.

The products mentioned above are commercial products. Those which are not commercially available can be prepared according to the teaching of the state of the art, by hydrolysis or co-hydrolysis of the corresponding chlorosilanes. We can refer in particular to the book W.

NOLL, Chemistry and Technology of Silicones - Academy Press 1968.

According to the process of the invention, the reduction of a phosphonate (II) type compound which can be monofunctional (monophosphonate) or bifunctional (bisphosphonate), the two phosphonate groups can be carried by an aliphatic chain, by one cycle or two different cycles.

By way of illustration, the monophosphonate compounds are defined by the following formula:

O

H .OR _b

R- a P

OR _r

(Ha) in said formula, R _a represents a hydrocarbon group having from 1 to 20 carbon atoms,

Rb and R ₀ represent a hydrocarbon group having 1 to 20 carbon atoms. In the formula (Ma), Rb and R ₀ represent a hydrocarbon group of any kind. However, since they are leaving groups, it is interesting from an economic point of view that they are of a simple nature and more particularly represent a linear or branched alkyl group having from 1 to 4 carbon atoms, from preferably a methyl or ethyl group but it may also represent for example a phenyl group.

It should also be mentioned that the groups Rb and R ₀ may be bonded together for example by an alkylene group having 1 to 6 carbon atoms, preferably ethylene.

In said formula (Ma), R _a represents a hydrocarbon group of any nature. Preferred meanings will be specified in the present text, but without any limiting character.

More specifically, R ₃ represents a hydrocarbon group having from 1 to 20 carbon atoms which may be a saturated or unsaturated, linear or branched acyclic aliphatic group; a saturated, unsaturated or aromatic, monocyclic or polycyclic carbocyclic or heterocyclic group; a sequence of aliphatic and / or carbocyclic and / or heterocyclic groups as previously defined.

R _a preferably represents a linear or branched acyclic aliphatic group preferably having from 1 to 12 carbon atoms, saturated. The invention does not exclude the presence of unsaturation on the hydrocarbon chain such as one or more double bonds which may or may not be conjugated or a triple bond.

The hydrocarbon chain may be optionally interrupted by a heteroatom (for example, oxygen or sulfur) or by a functional group to the extent that it does not react and there may be mentioned in particular a group such as in particular ether.

The hydrocarbon chain may optionally carry one or more substituents insofar as they do not react under the reaction conditions, and a halogen atom or a trifluoromethyl group may be mentioned in particular.

In the formula (Ma), R ₃ may represent a monocyclic carbocyclic group. The number of carbon atoms in the cycle can vary from 3 to 8 carbon atoms, but is preferably 5 or 6 carbon atoms.

The carbocycle may be saturated or comprising 1 or 2 unsaturations in the ring, preferably 1 to 2 double bonds. Preferred examples of R _a groups include cyclohexyl, cyclobutene-yl, cyclohexene-yl or cyclopentadien-yl.

R _a may also represent a polycyclic hydrocarbon group consisting of at least 2 saturated and / or unsaturated carbocycles or with at least 2 carbocycles of which only one of them is aromatic and forming between them ortho- or ortho- and peri-condensed systems . Generally, the rings are in C3 to Cs, preferably in Ce. More specific examples include the bornyl group or the tetrahydronaphthalene group.

R _a may represent a monocyclic aromatic carbocyclic group having from 4 to 8 carbon atoms, preferably a phenyl group. R _a may also represent a polycyclic aromatic carbocyclic group; the cycles can form between them ortho-condensed, ortho- and peri-condensed systems. There may be mentioned more particularly, a naphthyl group.

In the case where R _a represents a carbocyclic, monocyclic, saturated or unsaturated group, it is possible for one or more of the carbon atoms of the ring to be replaced by a heteroatom, preferably oxygen, nitrogen or sulfur, or by a group functional, preferably carbonyl or ester, thereby leading to a monocyclic heterocyclic compound. The number of atoms in the ring can vary widely from 3 to 8 but is preferably 5 or 6 atoms. In this case the heteroatom must be connected to a carbon atom and not to a phosphorus atom.

R _a may also represent a polycyclic aromatic heterocyclic group defined as being either a group consisting of at least 2 aromatic or non-aromatic heterocycles containing at least one heteroatom in each ring and forming between them ortho- or ortho- and peri-condensed systems or a group constituted by at least one aromatic or non-aromatic hydrocarbon ring and at least one aromatic or non-aromatic heterocycle forming between them ortho- or ortho- and peri-condensed systems.

As examples of heterocyclic R ₃ groups, there may be mentioned, inter alia, furyl, thienyl, isoxazolyl, furazanyl, isothiazolyl, pyridyl, pyridazinyl, pyrimidinyl and pyranyl groups, and quinolyl, naphthyridinyl, benzopyranyl and benzofuranyl groups. It should be noted that if the groups R _a comprise any ring, it is possible that this ring carries a substituent. The nature of the substituent is any as long as it does not interfere with the desired product. The substituents most often borne by the ring are one or more alkyl or alkoxy groups preferably having from 1 to 4 carbon atoms, preferably methyl or methoxy, an alkenyl group, preferably an isopropenyl group, an atom of halogen, preferably chlorine or bromine, a trihalomethyl group, preferably trifluoromethyl and more particularly nitrile or ester functional groups (preferably lower alkyl CrC ₄ ). In formula (I), R _a also represents a chain of aliphatic and / or carbocyclic and / or heterocyclic groups.

Thus, an acyclic aliphatic group, saturated or unsaturated, linear or branched may optionally carry a cyclic substituent. By ring is meant a carbocyclic or heterocyclic ring, saturated, unsaturated or aromatic.

The acyclic aliphatic group may be linked to the ring by a valency bond, a heteroatom or a functional group such as oxy, carbonyl, carboxy, sulfonyl etc.

As examples of cyclic substituents, it is possible to envisage cycloaliphatic, aromatic or heterocyclic, in particular cycloaliphatic, substituents comprising 6 ring carbon atoms or benzenes, these cyclic substituents being themselves optionally carrying any substituent insofar as they do not do not interfere with the reactions involved in the process of the invention. In particular, alkyl or alkoxy groups having 1 to 4 carbon atoms may be mentioned.

Among the linear or branched aliphatic groups, alkyl groups having from 1 to 10 carbon atoms are particularly targeted.

Among the aliphatic groups bearing a cyclic substituent, aralkyl groups having from 7 to 12 carbon atoms, in particular benzyl or phenylethyl, are more particularly contemplated.

When the group R _a comprises more than one cyclic ring (carbocycle or heterocycle), the cyclic rings may be condensed (o- or pericondensed) two by two or attached in pairs by σ bonds.

As examples, there may be mentioned a biphenyl group. Of all the aforementioned R _a groups, R _a preferably represents an alkyl group having 1 to 12 carbon atoms, a phenyl or naphthyl group. With regard to bisphosphonate compounds, they can be represented by the following formula:

O O

R O., OR ^ b P -A

\

P OR,

C (Hb) in said formula, - A represents a divalent hydrocarbon group having 1 to 40 carbon atoms,

- R _b and R ₀ , represent a hydrocarbon group having 1 to 20 carbon atoms.

In the formula (Mb), Rb and R ₀ , have the meaning given in the formula (Ma) but preferably represent an alkyl group having 1 to 4 carbon atoms.

As for A, its nature is very varied. It can be a divalent aliphatic group having from 1 to 20 carbon atoms, a cyclic, monocyclic or polycyclic, carbocyclic or heterocyclic, saturated, unsaturated or aromatic cyclic group having from 3 to 40 carbon atoms, a series of groups aliphatic and cyclic as defined.

More specifically, A represents a divalent, aliphatic, acyclic, linear or branched group preferably having from 1 to 12 carbon atoms, saturated or unsaturated, which may comprise one or more double bonds which may or may not be conjugated, or else a triple bond.

The hydrocarbon chain may be optionally interrupted by a heteroatom (for example, oxygen or sulfur) or by a functional group or bearing one or more substituents, insofar as they do not react under the reaction conditions and may be mentioned in particular. a halogen atom, a trifluoromethyl group.

Thus, in formula (Mb), A preferably represents a linear or branched alkylene group having from 1 to 12 carbon atoms.

Examples of divalent aliphatic groups are: - CH 2 -; - CH2 - CH2 -; - CH2 - CH2 - CH2 -; - CH2 - CH2 - CH2 - CH2 -; - CH ₂ - CH ₂ - CH ₂ - CH ₂ - CH ₂ -; - CH = CH -; - C ≡ C -

In the formula (Mb), A can represent a divalent carbocyclic, monocyclic, saturated or unsaturated group, preferably comprising 1 or 2 double bonds. The number of carbon atoms in the ring can range from 3 to 8 atoms, but preferably from 5 to 6 carbon atoms.

Thus, A preferably represents a cyclohexylene, cyclobutenylene, cyclohexenylene or cyclopentadienylene group or a group of formula:

In the formula (Mb), A may also represent a divalent carbocyclic, polycyclic group consisting of at least 2 saturated and / or unsaturated carbocyclic rings or by at least 2 carbocycles of which only one of them is aromatic and forming between them ortho- or ortho- and peri-condensed systems. Generally, the rings are in C3 to Cs, preferably in Ce. As more specific examples, mention may be made of the groups of formula:

A may represent a divalent aromatic carbocyclic group having from 4 to 8 carbon atoms, preferably a phenylene group.

A may also represent a polycyclic aromatic carbocyclic divalent group; the cycles can form between them ortho-condensed, ortho- and peri-condensed systems. More particularly, a naphthalenylene group may be mentioned.

Examples of preferred aromatic divalent groups are given below:

In the case where A represents a carbocyclic, monocyclic, saturated or unsaturated group, it is possible for one or more of the carbon atoms of the ring to be replaced by a heteroatom, preferably oxygen or nitrogen. or sulfur or with a functional group, preferably carbonyl or ester, thereby leading to a monocyclic heterocyclic compound. The number of atoms in the ring can vary widely from 3 to 8 but is preferably 5 or 6 atoms. In this case the heteroatom must be connected to a carbon atom and not to a phosphorus atom.

A may also represent a polycyclic aromatic heterocyclic divalent group defined as being either a group consisting of at least 2 aromatic or non-aromatic heterocycles containing at least one heteroatom in each ring and forming between them ortho- or ortho- and peri-condensed systems or a group constituted by at least one aromatic or non-aromatic hydrocarbon ring and at least one aromatic or non-aromatic heterocycle forming between them ortho- or ortho- and peri-condensed systems.

As examples of groups A of heterocyclic type, there may be mentioned, inter alia, the following groups:

It should be noted that if the groups A comprise any cycle, it is possible that this cycle carries a substituent. The nature of the substituent is any as long as it does not interfere with the desired product. One can refer as examples to the substituents stated for formula (Ia). Of all the aforementioned groups A, A preferably represents an alkylene group having 1 to 12 carbon atoms, a phenylene or naphthyleneylene group: the aromatic rings may be substituted.

As in the group R _a , the invention does not exclude the succession of aliphatic and / or cyclic groups. As examples of this type of group, the invention particularly relates to the following groups:

in which Rd, R _e are independently selected on each cycle:

. Rd, R _e represent a hydrogen atom; an alkyl or alkoxy group having 1 to 6 carbon atoms, . two groups Rd and R _e attached to the same phenyl ring together form an unsaturated or aromatic carbocycle, or together form an unsaturated or aromatic heterocycle.

According to the invention, R _d and R _e are independently chosen from a hydrogen atom, (d-C6) alkyl or (Ci-Cβ) alkyloxy, preferably methyl or methoxy.

As preferred examples, mention may be made of the following groups of formula (IV):

In formula (IV), two groups Rd and R _e attached to the same phenyl ring together form a carbocycle or a heterocycle.

When Rd and R _e together form a carbocycle or an unsaturated heterocycle, it preferably has a single unsaturation which is that shared with the phenyl ring bearing groups Rd and R _e .

The aromatic carbocycles that together form Rd and R _e are preferably the Cβ-Cis, monocyclic or polycyclic rings: the cyclic rings may be fused in pairs or may also comprise a ring attached to an aromatic ring via a σ bond. Rd and R _e advantageously form a benzene or naphthalenic ring.

The unsaturated carbocycles that together form Rd and R _e are mono- or polycyclic. These carbocycles preferably comprise from 4 to 20 carbon atoms, more preferably from 4 to 20 carbon atoms. Examples include C 4 -C 10 cycloalkenyl.

By heterocycle is meant according to the invention mono- or polycyclic groups and in particular mono-, bi- or tricyclic comprising one or more heteroatoms selected from O, S and / or N, preferably 1 to 4 heteroatoms.

When the heterocycle is polycyclic, it may consist of several unicycles condensed two by two (orthocondensed or pericondensed) and / or several unicycles attached in pairs by σ bonds. Preferably, the monocycles or the unocycle constituting the heterocycle, has from 5 to 12 atoms, more preferably from 5 to 10 atoms, for example from 5 to 6 atoms.

When Rd and R _e form a heterocycle, it comprises an unsaturated part and / or an aromatic part, it being understood that the unsaturated part preferably comprises a single double bond.

Particularly preferred heterocycles include pyridine, furan, thiophene, pyrrole, benzofuran and benzothiophene.

In the context of the invention, the monocyclic or bicyclic carbocycles and heterocycles are preferred.

In a preferred manner, Rd and R _e together with the carbon atoms carrying them (i) form a monocyclic or polycyclic, unsaturated or aromatic carbocycle having 5 to 13 carbon atoms, or (ii) a monocyclic or polycyclic heterocycle. , unsaturated or aromatic have from 4 to 12 carbon atoms and one or more heteroatoms selected from O, S and N, said heterocycle and carbocycle being optionally substituted. The substituents are preferably one or more (C 1 -C 6) alkyl or (C 1 -C 6) alkyloxy.

A group of preferred compounds is constituted by phosphonates comprising a group of formula (IV) for which Rd and R _e together form an optionally substituted (C ₄ -C 10) cycloalkene, an optionally substituted (C ₆ -C ₁₂ ) arene or a (C ₄ -C 8) heteroarene comprising 1 or 2 endocyclic heteroatoms, said heteroarene being optionally substituted.

R _d and R _e are more preferably together cyclohexene or optionally substituted benzene. Thus, are particularly concerned, the phosphonates whose naphthyl groups are substituted in the position 3,3 'or 4,4' or 5,5 'or 6,6' or 7,7 ', by atoms or functional groups and which can be represented by the following formula:

- Rf, R ₉ , identical or different, represent a hydrogen atom or a substituent, - Xi, X ₂ , identical or different, represent: . R, alkyl, alkenyl, alkynyl, cycloalkyl, aryl, arylalkyl, an alkyl group substituted with one or more halogen atoms, preferably fluorine or with amino groups, a halogen atom selected from bromine, chlorine or iodine, a group -OH,

. a group -OR _h ,. a group -S-Rh. a group -CH ₂ -NH ₂ ,. a group -CH ₂ OH,. a group -CH ₂ -NH ₄ ⁺ ,

. a group comprising a nitrogen atom such as: an NH ₂ group. a group -NHR _h ,. a group -N (Rh) ₂ , an -NH-NH _{2 group} , in the various formulas, R _h represents an alkyl, cycloalkyl, arylalkyl or phenyl group.

In the formula (V), the term "alkyl", a linear or branched hydrocarbon chain C1-C15 and preferably C1-C10. Examples of preferred alkyl groups include methyl, ethyl, propyl, isopropyl, butyl, isobutyl and t-butyl.

By "alkenyl" is meant a hydrocarbon group, linear or branched C ₂ -C ₅ comprising one or more double bonds, preferably 1 to 2 double bonds. By "alkynyl" is meant a hydrocarbon group, linear or branched in

C ₂ -C ₅ , comprising one or more triple bonds, preferably 1 triple bond.

By "cycloalkyl" is meant a C ₃ -C ₈ monocyclic cyclic hydrocarbon group, preferably a C ₄ -C ₈ cyclopentyl or cyclohexyl or polycyclic (bicyclic or tricyclic) group, especially adamantyl or norbornyl.

"Aryl" means a mono- or polycyclic aromatic group, preferably mono- or bicyclic C 6 -C ₂ o, preferably phenyl or naphthyl. When the group is polycyclic, that is to say that it comprises more than one ring nucleus, the ring nuclei can be condensed two by two or attached in pairs by bonds σ. Examples of (C ₆ -C ₁₈ ) aryl groups include phenyl, naphthyl, anthryl and phenanthryl. By "arylalkyl" is meant a hydrocarbon group, linear or branched bearer of a monocyclic aromatic ring C ₇ -C _2, preferably benzyl.

The substituents denoted by R _f and R ₉ are in particular (d-Cβ) alkyl or (C 1 -C 6) alkyloxy groups.

The different groups X ₁ and X ₂ are advantageously in the 6,6 'or 5,5' or 4,4 'position.

As examples of the preferred meaning of the group A corresponding to the formula (IV), there may be mentioned the following groups:

(with w between 1 and 5)

The invention is particularly applicable to bisphosphonates comprising two binaphthyl groups connected by a valence bond and substituted by the phosphorus atom in the ortho and ortho position.

The process of the invention is suitable for the reduction of any phosphonate group, but preferred examples of monophosphonates and dialkyl bisphosphonates are given below. In the following statement of the examples, the term "dialkyl" means two alkyl groups (R _b ), (R _c ), identical or different, preferably identical, having from 1 to 4 carbon atoms such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl or tert-butyl and more preferably a methyl or ethyl group.

We can mention in particular, as dialkyl monophosphonates:

dialkyl alkylphosphonates such as methylphosphonate, ethylphosphonate, chloromethylphosphonate or dialkyl dichloromethylphosphonate, dialkyl alkenylphosphonates such as dialkyl vinylphosphonate,

dialkyl arylphosphonates such as dialkyl phenylphosphonate, dialkyl p-methylphenylphosphonate,

In particular, dialkyl bisphosphonates may be mentioned: tetraalkyl alkylbisphosphonates, such as tetraalkyl ethanebisphosphonate, tetraalkyl dodecanebisphosphonate, tetraalkyl alkenylbisphosphonates, such as that the tetraalkyl vinylidene-1,1-diphosphonate,

tetraalkyl aryl-bisphosphonates such as dialkyl ferrocenyl-bis-phosphonate, tetraalkyl benzene-bis-phosphonate, tetraalkyl tetramethylbenzene-bis-phosphonate. The various phosphonates involved in the process of the invention are known products or they can be prepared according to the methods described in the literature. For example, alkylphosphonates can be prepared according to the Michaelis-Arbuzov reaction (Chem Rev. 81, 415-430) from an alkyl halide and a thalkylphosphite.

The arylphosphonates may in particular be synthesized according to a coupling reaction between an aryl halide and a dialkylphosphite, in the presence of a copper or palladium catalyst (J. Org., Chem., 2006, 71, 5020).

According to the process of the invention, the substrate comprising at least one phosphonate group, hereinafter referred to as "phosphonate substrate" and a siloxane compound, is reacted.

The amount of the compound of formula (I) to be used expressed relative to the amount of phosphonate functions to be reduced is at least equal to the stoichiometry. Thus, the ratio between the number of moles of the formula (I) and the number of moles of phosphonate function to be reduced varies between 1 and 1000, preferably between 1 and 50.

In the process of the invention, a catalyst based on a metallic and / or metalloidal element as defined above is involved.

As metal or metalloid cations which are quite suitable for the implementation of the invention, mention may be made more particularly of those metal or metalloid elements of groups (IVA), (VIIA), (IB), (MB), ( MIB) and (VIII) of the periodic table of elements.

In the present text, reference is made hereinafter to the Periodic Table of Elements published in the Bulletin de la Société Chimique de France, No. 1 (1966).

As examples of cations that are well suited to the process of the invention, mention may be made more particularly of those of group (IVA), titanium, zirconium, hafnium; group (VIIA), manganese; group (IB), copper; group (MB), zinc; group (MIB) boron and aluminum; group (VIII), iron, cobalt, nickel.

Among the abovementioned cations, titanium is preferably chosen. As more specific examples of anions, there may be mentioned in particular organic anions such as carboxylates, preferably acetate, propionate, benzoate: sulphonates, preferably methanesulphonate, trifluoromethanesulphonate: alkoxides, preferably methylate, ethylate, propylate, isopropylate; acetylacetonate. As regards the inorganic anions, there may be mentioned in particular chloride, bromide, iodide, carbonate.

An organic anion is advantageously chosen.

There may also be presence of hydrocarbon groups by alkyl groups preferably having from 1 to 4 carbon atoms or cyclopentadienyl. As catalysts, preference is given to anhydrous compounds.

Examples of compounds which may be used in the process of the invention are given below:

- composed of iron:. iron acetate (II)

. iron acetylacetonate (II). iron bromide (II). iron bromide (Ml) . iron chloride. iron (III) ethoxide. iron i-propoxide. iron stearate (III). iron trifluoroacetylacetonate

- cobalt compound:

. cobalt (II) acetate

. cobalt (II) acetylacetonate

. bis (cyclopentadienyl) cobalt (II). cobalt (II) bromide

. cobalt (II) chloride

. cobalt citrate (II)

. cobalt (II) cyclohexanebutyrate

. Cobalt (II) 2-ethylhexanoate. (7R, 2R) - (-) - 1, 2-Cyclohexanediamino-N, N'-bis (3,5-di-t-butylsalicylidene) cobalt (II)

- nickel compound:

. nickel acetylacetonate (II). nickel bromide (II). nickel chloride (II)

. nickel hexafluoroacetylacetonate (II)

- composed of titanium:

. dichloride bis (cyclopentadienyl) titanium

. dichloride bis (ethylcyclopentadienyl) titanium. titanium triisopropoxide chloride

. titanium cyclopentadienyl trichloride

. trimethoxide pentamethylcyclopentadienyl titanium

. titanium bromide (IV)

. n-butoxide titanium (IV). Titanium t-butoxide (IV)

. Titanium chloride (IV)

. (di-i-propoxide) bis (acetylacetonate) titanium

. titanium ethoxide

. titanium fluoride (III). Titanium i-propoxide (IV)

- composed of zirconium:

. bis (cyclopentadienyl) zirconium dichloride

. zirconium bis (tretramethylcyclopentadienyl) dichloride . n-butyl dichloride (cyclopentanedienyl) zirconium. cyclopentadienyl zirconium trichloride. zirconium acetylacetonate (IV). n-butoxide zirconium (IV). t-butoxide zirconium (IV)

. zirconium n-propoxide (IV). zirconium trifluoroacetylacetonate (IV)

- composed of hafnium:

. hafnium acetylacetonate (IV). hafnium bromide (IV)

. hafnium t-butoxide (IV)

. hafnium chloride (IV)

. hafnium ethoxide (IV)

. hafnium monoisopropylate (IV) propoxide - boron compound:

. boron bromide

. th-n-amylborate

. th-n-butylborate

- composed of copper:. copper (II) acetate,

. copper acetylacetonate (II)

. copper bromide (II)

. copper (II) ethylacetoacetate

. copper (II) ethylhexanoate. copper fluoride (II)

. copper formate (II)

. copper (II) oxalate

. Copper tartrate (II)

. trifluoroacetylacetonate copper (II). copper trifluoromethanesulfonate (II)

- composed of aluminum:

. aluminum ethoxide. aluminum fluoride. aluminum hexafluoroacetylacetonate. aluminum i-propoxide

- zinc compound:

. zinc acetate

. zinc acetylacetonate . zinc bromide. zinc chloride. zinc cyclohexanebutyrate. 2-ethylhexanoate zinc. zinc fluoride

. zinc iodide

. zinc trifluoromethanesulfonate - manganese compound:

. bis (cyclopentadienyl) manganese. bis (ethyl cyclopentadienyl) manganese

. bis (pentanemethylcyclopentadienyl) manganese. bis (i-propylcyclopentadienyl) manganese. bis (tetramethylcyclopentadienyl) manganese

. (1 R) - (R) - (-) - [1,2-Cyclohexanediamino-N, N'-bis (3,5-di-tert-butylsalicylidene)] manganese (III) chloride

. ('- / S, 2S> (+) - [1,2-cyclohexanediamino-N-N'-bis (3,5-di-t-butylsalicylidene)] manganese (III) chloride, cyclopentadienyl manganese tricarbonyl, acetylacetonate, manganese (III) manganese bromide (II)

. manganese carbonate (II). manganese chloride (II). manganese cyclohexanebutyrate (II). 2-ethylhexanoate of manganese (II). manganese fluoride (II)

. manganese iodide (II). pentacarbonyl bromide of manganese. Phthalocyanine of manganese (III). thcarbonylmethylcyclopentadienylmanganese The invention does not exclude a catalyst comprising a mixture of compounds of the aforementioned elements.

As more specific examples of complexes of the aforementioned metals, mention may be made of titanium isopropoxide or zinc trifluoroacetate.

The amount of catalyst used, expressed as the ratio between the number of moles of metal and / or metalloid element and the number of moles of phosphonate function to be reduced varies between 0.05 and 1, and preferably between 0.05 and 0.5. The process of the invention is preferably carried out in an organic solvent.

It is also possible that one of the excess reagents serve as a reaction solvent. A solvent which is inert under the reaction conditions and which preferably solubilizes the reactants is used.

Advantageously, the solvent is chosen such that its boiling point is high (preferably greater than 60 ^° C.).

As examples of organic solvents that are suitable for the invention, mention may in particular be made of aliphatic, cycloaliphatic or aromatic halogenated or non-halogenated hydrocarbons; the ethers.

As nonlimiting examples of solvents, mention may be made of:

aliphatic and cycloaliphatic hydrocarbons, more particularly paraffins such as, in particular, hexane, heptane, octane, isooctane, nonane, decane, undecane, tetradecane, petroleum ether, cyclohexane and methylcyclohexane; aromatic hydrocarbons such as, in particular, benzene, toluene, xylenes, ethylbenzene, diethylbenzenes, trimethylbenzenes, cumene, pseudocumene, petroleum fractions consisting of a mixture of alkylbenzenes, especially Solvesso® type cuts,

aliphatic or aromatic halogenated hydrocarbons and there may be mentioned: perchlorinated hydrocarbons such as in particular 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,

aliphatic, cycloaliphatic or aromatic ethers and, more particularly, methyl tert-butyl ether, dipentyl ether, diisopentyl ether, dimethylether of ethylene glycol (or 1,2-dimethoxyethane), dimethyl ether of diethylene glycol (or 1,5-dimethoxy-3-oxapentane), anisole or cyclic ethers, for example, dioxane, tetrahydrofuran. Toluene, methylcyclohexane, is advantageously chosen.

The amount of organic solvent used is such that the concentration of the phosphonate substrate is advantageously between 0.1 and 1 mol / liter, preferably around 0.5 mol / liter. According to the process of the invention, the phosphonate substrate is brought into contact with the compound of formula (I) in the presence of the catalyst and preferably in an organic solvent. As regards the temperature and pressure conditions, they are advantageously as described below.

The reduction reaction is generally carried out at a temperature ranging from room temperature to 150 ^° C., preferably from 60 ^{° to} 120 ^° C.

By ambient temperature is meant a temperature most often between 15 ° C and 25 ° C.

The duration of the reduction can vary widely between 2 hours and 24 hours, depending on the amount of catalyst used and the temperature of the reaction.

The process of the invention is carried out under atmospheric pressure but preferably under a controlled atmosphere of inert gases such as nitrogen or rare gases, for example argon. A pressure slightly above or below atmospheric pressure may be suitable.

With regard to the practical embodiments of the invention, a preferred mode consists of charging the phosphonate substrate to be reduced in the organic solvent, then introducing the reducing compound of formula (I) and then the catalyst based on a metallic and / or metalloidal element.

At the end of the reaction, the reduced product is recovered.

For this purpose, the methods conventionally used and in particular the distillation are used.

To protect the primary phosphine function (s) from the oxidation, complexes with a borohydride can be made by reacting the phosphine with, for example, a BH ₃ , THF or NaBH ₄ complex in THF. For this purpose, reference can be made to the teaching of literature (JACS 1990, 112, 5244).

If necessary, deprotection can be carried out in a known manner, for example with the aid of trifluoroacetic acid.

An exemplary embodiment of the invention given for illustrative and non-limiting purposes is given below.

In the examples, the yield (RR) is defined as the ratio between the number of moles of product formed and the number of moles of phosphonate substrate employed. Example 1

Preparation of ethane-bis-phosphine by reduction of tetramethyl ethane-bis-phosphonate

In a dry sealed tube and under an argon atmosphere, (1 g, 4.63 mmol, 1 eq) of phosphonate is placed in 6 ml of toluene.

(6.5 ml, 37 mmol, 8 eq) of tetramethyldisiloxane and (1.37 ml, 4.63 mmol, 1 eq) of titanium isopropoxide are added.

The tube is sealed and then stirred and heated at 110 ⁰ C for 5 hours. Cooled and then sampled for ³¹ P NMR analysis (81

MHz, CDCl ₃ ): -131 ppm.

A yield of 95% expressed relative to the phosphonate employed is determined.

Example 2

Preparation of dodecane-bis-phosphine by reduction of tetraisopropyl dodecane-bis-phosphonate

9 O

(! -Pr-O) ₂ P "M ₁₀ P (OI-Pr) - H ₂ P ^' M ₁₀ PH ₂

In a dry sealed tube and under an argon atmosphere, (1 g, 2 mmol, 1 eq) of phosphonate in 6 ml of toluene is placed.

(2.8 ml, 16 mmol, 8 eq) of tetramethyldisiloxane and (0.6 ml, 2 mmol, 1 eq) of titanium isopropoxide are added.

The tube is sealed and then stirred and heated at 110 ⁰ C for 15 hours. Cool and then take a sample for analysis. ³¹ P NMR (81 MHz, CDCl ₃ ): -136 ppm.

A yield of 95% expressed relative to the phosphonate employed is determined. Example 3

Preparation of phenylphosphine by reduction of diethyl phenylphosphonate

In a dry sealed tube and under an argon atmosphere (0.65 ml, 3.4 mmol, 1 eq) of phosphonate in 6 ml of toluene is placed.

(2.4 ml, 13.6 mmol, 4 eq) of tetramethyldisiloxane and (0.5 ml, 1.7 mmol, 0.5 eq) of titanium isopropoxide are added.

The tube is sealed and then stirred and heated at 110 ⁰ C for 24 hours. Cool and then take a sample for analysis. ³¹ P NMR (81

MHz, CDCl ₃ ): -121 ppm.

A yield of 80% expressed relative to the phosphonate employed is determined.

Example 4

(2 ml, 32 mmol, 16 eq.Si-H) of polymethylhydrosiloxane and (0.6 ml, 2 mmol, 1 eq) of titanium isopropoxide are added.

A yield of 93%, expressed relative to the phosphonate employed, is determined.

Example 5 Preparation of octylphosphine protected with BH ₃ .

In a dry sealed tube and under an argon atmosphere, (1, 7 mmol) of diethyloctylphosphonate is placed in 3 ml of methylcyclohexane. Tetramethyldisiloxane (TMDS) (3.9 mmol, 0.37 ml) and (0.33 mmol, 0.10 ml, 0.2 eq) titanium isopropoxide were added.

The tube is closed and then stirred and heated at 60 ^° C. for 6 hours.

A sample is then taken for ³¹ P NMR analysis which indicates a total conversion.

At 0 ^° C., (3.4 mmol, 3.4 ml) of BH ₃ THF is added to the reaction medium.

After stirring for 1 hour, the silica (2 g) is added gradually.

The suspension is filtered through silica, rinsed with dichloromethane.

After concentration, the residue is purified on silica gel (EtOAc / cyclohexane: 3/1) to give the octylphosphine protected by BH ₃ with a yield of 83%.

Claims

1 - Process for the preparation of a primary phosphine from the corresponding phosphonate, characterized in that it comprises placing the substrate comprising at least one phosphonate group in the presence of a siloxane-type compound corresponding to the following formula (I ) associated with a catalyst based on a metallic and / or metalloidal element chosen from (NIA), (IVA), (VA), (VIA), (VIIA), (VIII), (IB), (MB) ), (NIB), (IVB), (VB) of the Periodic Table of Elements:

Ri R ₂ ^R 5 ^R i

R - Si O - (- Si - O) ^ (- Si - O) ^ Si - R ₃

R ⁱ * ⁴ Re R _{1 (|)} in said formula:

- Ri, R _2, R 5, R _Θ, identical or different, represent an alkyl, cycloalkyl or aryl,

R3 represents a hydrogen atom or an alkyl, cycloalkyl or aryl group,

R ₄ represents a hydrogen atom,

x is a number ranging from 0 to 50,

y is a number ranging from 0 to 50,

if x and y ≠ 0, then R ₃ represents an alkyl, cycloalkyl or aryl group,

if x = 0 and y ≠ 0, then R3 represents a hydrogen atom,

if x ≠ 0 and y = 0, then R ₃ represents an alkyl, cycloalkyl or aryl group.

2 - Process according to claim 1 characterized in that the siloxane compound of the formula (I) wherein R 1, R ₂ , R ₃ , R 5, Re are identical and represent an alkyl group having 1 to 4 atoms carbon, preferably a methyl group.

3 - Process according to one of claims 1 and 2 characterized in that the siloxane-type compound corresponds to the formula (I) wherein y is equal to 0 and x is equal to 0 or between 45 and 50. 4 - Process according to one of claims 1 to 3 characterized in that the siloxane compound is tetramethyldisiloxane, methylhydrogenpolysiloxane or a polysiloxane.

5 - Process according to one of claims 1 to 4 characterized in that the phosphonate substrate has the following formula:

O

H ^ OR _b RP

^X ° ^Rc (IIa) in said formula,

R _a represents a hydrocarbon group having from 1 to 20 carbon atoms,

- Rb and R ₀ , represent a hydrocarbon group having 1 to 20 carbon atoms.

6 - Process according to claim 5 characterized in that the phosphonate substrate has the formula (Ma) wherein R _a represents a hydrocarbon group having 1 to 20 carbon atoms which may be a saturated or unsaturated, linear acyclic aliphatic group or branched; a saturated, unsaturated or aromatic, monocyclic or polycyclic carbocyclic or heterocyclic group; a sequence of aliphatic and / or carbocyclic and / or heterocyclic groups as previously defined.

7 - Process according to claim 6 characterized in that the phosphonate substrate has the formula (Ma) wherein R _a represents an alkyl group having 1 to 10 carbon atoms or an optionally substituted phenyl group.

8 - Process according to one of claims 1 to 4 characterized in that the phosphonate substrate

in said formula,

A represents a divalent hydrocarbon group having 1 to 40 carbon atoms, - Rb and R ₀ , represent a hydrocarbon group having 1 to 20 carbon atoms.

9 - Process according to claim 8 characterized in that the phosphonate substrate has the formula (Mb) wherein A represents a divalent aliphatic group having 1 to 20 carbon atoms, a cyclic group, monocyclic or polycyclic, carbocyclic or heterocyclic saturated, unsaturated or aromatic having from 3 to 40 carbon atoms, a chain of aliphatic and cyclic groups as defined.

10 - Process according to claim 9, characterized in that the phosphonate substrate corresponds to the formula (Mb) in which A represents a divalent group of formula:

wherein Rd, R _e are independently selected on each ring: Rd, R _e represent a hydrogen atom; an alkyl or alkoxy group having 1 to 6 carbon atoms,

. two groups Rd and R _e attached to the same phenyl ring together form an unsaturated or aromatic carbocycle, or together form an unsaturated or aromatic heterocycle.

11 - Method according to one of claims 9 and 10 characterized in that the phosphonate substrate has the formula (Mb) wherein A represents a divalent group of formula:

(V) - Rf, R ₉ , identical or different, represent a hydrogen atom or a substituent,

- Xi, X2, identical or different, represent:

. R, alkyl, alkenyl, alkynyl, cycloalkyl, aryl, arylalkyl, an alkyl group substituted with one or more halogen atoms, preferably fluorine or with amino groups, a halogen atom selected from bromine, chlorine or iodine, a group -OH, a group -O-Rh,. a group -SR _h

. a group -CH ₂ -NH ₂ ,. a group -CH ₂ OH,. a group -CH ₂ -NH ₄ ⁺ ,

. a group comprising a nitrogen atom such as: an NH ₂ group

. a group -NHR _h ,. a group -N (Rh) ₂ , a -NH-NH _{2 group} , in the various formulas, Rh represents an alkyl, cycloalkyl, arylalkyl or phenyl group.

12 - Process according to claim 8, characterized in that the phosphonate substrate corresponds to the formula (Mb) in which A represents a linear or branched alkylene group having from 1 to 12 carbon atoms, a phenylene group, a naphthylene group or a divalent group comprising two naphthyl groups connected in the ortho and ortho 'position by a valency bond.

13 - Method according to one of claims 5 and 8 characterized in that the phosphonate substrate has the formula (Ma) or (Mb) wherein Rb and R ₀ , represent a linear or branched alkyl group having 1 to 4 carbon atoms or Rb and R _{0 groups} may be bonded together for example by an alkylene group having 1 to 6 carbon atoms, preferably ethylene.

14 - Process according to claim 1, characterized in that the starting phosphonate substrate is chosen from:

dialkyl alkylphosphonates such as methylphosphonate, ethylphosphonate, chloromethylphosphonate or dialkyl dichloromethylphosphonate, dialkyl alkenylphosphonates, such as dialkyl vinylphosphonate,

dialkyl arylphosphonates such as dialkyl phenylphosphonate, dialkyl p-methylphenylphosphonate, tetraalkyl alkylbisphosphonates such as tetraalkyl ethanebisphosphonate, tetraacyl dodecanebisphosphonate, tetraalkyl alkenyl-bis-phosphonates such as tetraalkyl vinylidene-1,1-diphosphonate,

tetraalkyl aryl-bisphosphonates such as dialkyl ferrocenyl-bis-phosphonate, tetraalkyl benzene-bis-phosphonate, tetraalkyl tetramethylbenzene-bis-phosphonate.

15 - Method according to one of claims 1 to 14 characterized in that the ratio between the number of moles of the compound of formula (I) and the number of moles of phosphonate function to be reduced varies between 1 and 1000, preferably between 1 and 50.

16 - Method according to one of claims 1 to 15 characterized in that the catalyst is a compound comprising a metal or metalloidic cation of the metal or metalloid elements of groups (IVA), (VIIA), (IB), (MB) , (MIB) and (VIII) of the Periodic Table of Elements.

17 - Process according to claim 16 characterized in that the metal or metalloid element is selected from: titanium, zirconium, hafnium; manganese; the copper ; zinc; boron and aluminum; iron, cobalt, nickel.

18 - Method according to one of claims 16 and 17 characterized in that the anion is selected from carboxylates, preferably acetate, propionate, benzoate: sulfonates, preferably methanesulfonate, trifluoromethanesulfonate: alcoholates preferably methylate, ethylate, propylate, isopropylate; acetylacetonate.

19 - Method according to one of claims 16 and 17 characterized in that the anion is selected from: chloride, bromide, iodide, carbonate.

20 - Process according to one of claims 16 to 18 characterized in that the catalyst is titanium isopropoxide or zinc trifluoroacetate. 21 - Method according to one of claims 16 to 20 characterized in that the amount of catalyst implemented expressed by the ratio between the number of moles of metal element and / or metalloid and the number of moles of phosphonate function to reduce is between 0.05 and 1 and is preferably between 0.05 and 0.5.

22 - Process according to one of claims 1 to 21 characterized in that the reaction takes place in an organic solvent, preferably an aliphatic hydrocarbon, cycloaliphatic or aromatic halogenated or not; or an ether.

23 - Process according to claim 22 characterized in that the solvent is an aromatic or aliphatic hydrocarbon, preferably toluene or methylcyclohexane.

24 - Method according to one of claims 1 to 23, characterized in that the reduction reaction is conducted at a temperature ranging between room temperature and 150 ⁰ C, preferably between 60 and 120 ⁰ C.

25 - Process according to one of claims 1 to 24 characterized in that the method of the invention is conducted under atmospheric pressure but preferably under a controlled atmosphere of inert gas, preferably nitrogen.

26 - Process according to one of claims 1 to 25, characterized in that the phosphonate substrate is charged to reduce in the organic solvent, then the reducing compound of formula (I) is introduced and then the catalyst based on of a metallic and / or metalloidal element.