PROCESS FOR PREPARING HYDROBORANS BY HYDROGENOLYSIS OF (PSEUDO-)HALO-BORANES

Abstract

The present invention relates to a process for preparing hydroboranes by the hydrogenolysis of corresponding (pseudo-)haloboranes, in the presence of a base and optionally a catalyst. The process of the invention contributes to the circularity of the boron element by enabling the recycling of (pseudo-)haloborane compounds, common waste products of boron chemistry, into higher value-added hydroboranes. Figure for the abstract: None

Description

Title of the invention: METHOD FOR PREPARING HYDROBORANS BY HYDROGENOLYSIS OF (PSEUDO-)HALO-BORANES Technical field of the invention

[0001] The present invention is in the field of boron chemistry and more particularly in the synthesis of hydroboranes having one, two or three BH bonds per boron atom.

[0002] In particular, the present invention relates to a process for preparing hydroboranes by hydrogenolysis of corresponding (pseudo-)haloboranes in the presence of a base and optionally a catalyst.

[0003] The process of the invention is part of a circular approach to the boron element by allowing the recycling of (pseudo-) haloborane compounds, common waste from boron chemistry, towards higher value-added hydroboranes. Technical background

[0004] Hydroboranes have multiple uses in chemistry. They are involved in organic synthesis for the reduction of carbonyl groups and unsaturated carbon-carbon bonds, and also in the synthesis of boronic esters used for Suzuki coupling, for example. They also serve as hydride sources in the production of industrial molecules such as methanol, formic acid, ammonia, etc., from inorganic molecules (CO2, NOx).

[0005] The synthesis of hydroboranes is currently based essentially on the synthesis of borane BH3, the industrial synthesis of which is carried out in two steps as shown in [Fig. 1] and described by H.I. Schlesinger et al., J. Am. Chem. Soc., 1953, 75 (1), 205-209 and doi.org / 10.1002 / 14356007.a04_309; US3259474:

[0006] - reduction of trimethylborate (B(OMe)3) to sodium borohydride (NaBH4) by metallic sodium under high-temperature hydrogen pressure (Brown-Schlesinger or Bayer processes),

[0007] - reaction of sodium borohydride with trifluoroborane (BF3).

[0008] This process has a low energy balance since thermal and chemical energy must be supplied to produce an over-reduced intermediate product and relies, particularly in the first step, on hazardous reagents, especially metallic sodium. The material balance is also low since only 57% of the boron used is recovered as BH3.

[0009] On a laboratory scale, it has recently been shown by Camaioni that trichloro-roborane (BC13) in the presence of a nitrogenous base is able to activate hydrogen. Chloride recombination leads to partial hydrogenolysis of trichloro-roborane into dichloroborane (HBC12). However, this method is limited by a maximum theoretical yield of 50% ([Fig.2]) and does not allow the formation of C1BH2 and BH3 (Ginovska, B. et al., Chemistry - A European Journal, 2015, 21 (44), 15713-15719).

[0010] Hydrogen activation can be achieved heterolytically by combining a Lewis acid and base. Frustrated Lewis Pairs (FLPs) are well-documented special cases, particularly with the use of amino-borane derivatives. However, few examples deal with halogenated analogs such as amino-chloroboranes. Fontaine's group showed that a system based on a bis-aryl chloroborane functionalized with 2,2,6,6-tetramethylpiperidine (TMP) groups allows hydrogen activation in the zwitterionic form of bis-aryl chloroborohydride and an ammonium salt of TMP (M.-A. Courtemanche et al., Dalton Trans., 2016, 45 (14), 6129-6135). This product can also be considered as the addition product of HCl to the corresponding borane, and the authors demonstrate this by treating the latter with a strong base, 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD), which allows the formation of the supposed borane.This reactivity is, however, limited to a particular reagent, activated by its FLP character; hydrogen activation occurs intramolecularly, as shown in [Fig. 3]. This same group also points out that these hydrogenolysis reactions of haloborans to boranes are thermodynamically unfavorable and tend towards the formation of lower-energy haloborohydride and polyhaloborane derivatives (K. Chemichenko et al., Dalton Trans., 2017, 46 (7), 2263-2269).

[0011] Alternatively, the preparation of higher value-added hydroboranes such as alkylboranes and alkoxyboranes is possible by the sigma bond metathesis reaction between their halogenated or (pseudo-)halogenated analogs with a hydride donor, generally borane or silanes as shown in [Fig. 4]. To the inventors' knowledge, no industrially applicable synthetic methods for obtaining these high value-added boranes from hydrogen have ever been reported (H. Brown et al., Journal of Organometallic Chemistry, 1979, 168 (3), 281-293; A. Yeganeh-Salman, et al., Dalton Trans., 2022, 57 (47), 17962-17966). This very unselective process generally leads to statistical distributions of the different possible products, and further purification steps are required to isolate the product(s) of interest.It is also important to remember that these processes theoretically require stoichiometric amounts of hydrated reagents, but in practice, excesses of these reagents are often required. This leads to the generation of (over-)stoichiometric amounts of waste, the reprocessing of which is complex. In the case of the synthesis of alkylboranes and alkoxyboranes, a... A more selective method is preferred, involving the reaction between borane (BH3) and alkenes or alcohols respectively, but this method still presents selectivity issues. It again requires the production of borane (BH3) and therefore relies on energy-intensive processes, and it does not allow for boron circularity.

[0012] There is therefore a real need for a new hydroborane synthesis route that allows hydroboranes to be produced with an improved and economical energy balance compared to known synthesis routes.

[0013] In particular, there is a real need for a new efficient hydroborane synthesis route that can achieve high yields of hydroboranes formed under optimized operating conditions (yield > 50% for the desired product obtained) minimizing boron losses in the form of waste.

[0014] More particularly, there is a real need for a synthetic route for hydroboranes such as described above, from a wide range of borated reagents of interest.

[0015] Furthermore, there is a real need for a safer hydroborane synthesis route, particularly by reducing the quantity and hazard of the reagents involved. Summary of the invention

[0016] The present invention is specifically aimed at meeting these needs by providing a process for preparing a hydroborane of formula (I)

[0017] (RÛ^R^BH,,

[0018] from a (pseudo-)haloborane of formula (II)

[0019] (RJ^R^BXh

[0020] in which

[0021] - Ri and R2, identical or different, are an alkyl group comprising 1 to 12 atoms of carbon, a cycloalkyl group comprising 3 to 12 carbon atoms, an aryl group comprising 6 to 20 carbon atoms, an alkoxy group whose alkyl group comprises 1 to 12 carbon atoms, a cycloalkoxy (-O-cycloalkyl) group whose cycloalkyl group comprises 3 to 12 carbon atoms, an aryloxy group whose aryl group comprises 6 to 20 carbon atoms, an -NR3R4 group, with R3 and R4, identical or different, representing a hydrogen atom, an alkyl group comprising 1 to 12 carbon atoms, a cycloalkyl group comprising 3 to 12 carbon atoms, an aryl group comprising 6 to 20 carbon atoms, said alkyl and cycloalkyl groups being optionally substituted; or

[0022] - Ri and R2 taken together with the boron atom to which they are bonded, form a he- heterocycle comprising 5 to 12 members, said heterocycle group possibly being substituted;

[0023] -n is 1,2, 3;

[0024] - m is 0, 1;

[0025] - o is 0, 1;

[0026] - X represents Cl, Br, I, -OSO2R with R being a -CF3, -CH3 or o-tolyl, m- group tolyle, p-tolyle;

[0027] characterized in that the (pseudo-)haloborane of formula (II) is brought into contact with

[0028] (A) a catalyst selected from • a metallic complex in which the metal is a transition metal chosen from chromium, tungsten, manganese, rhenium, silver, rhodium, cobalt, iron, nickel, copper, iridium, ruthenium, osmium, molybdenum, gold, platinum and palladium, and the ligands linked to the transition metals are chosen from:

[0029] - nitrogenous bases such as tertiary amines selected from the 4-Dimethylaminopyridine (DMAP), 1,4-diazabicyclo[2.2.2]octane (DABCO), N-diisopropylethylamine (DIPEA or DIEA), bipyridyl (bipy), terpyridine (terpy); phenantroline (phen), ethylenediamine, A,A,MA'-tetramethylethylenediamine (TMEDA), quinoline and pyridine;

[0030] - phosphorus bases such as alkyl and aryl phosphines chosen from the tri- phenylphosphine, 2,2'-bis(diphenylphosphino)-l,r-binaphthyl (BINAP), triiso-propylphosphine, tris[2-diphenylphosphino)ethyl]phosphine (PP3), 4,5-bis-(di-i-propylphosphinomethyl)acridine, 4,5-bis-(di-phenylphosphinomethyl)acridine, tricyclohexylphosphine, 1,2-bis-diphenylphosphinoethane (dppe), 1,2-bis(diphenylphosphino)ethane (dppb); SPOCOP = (C6H4){ 1,3-OPR2}2) where R is an aryl group with 6 to 20 carbon atoms such as phenyl or an alkyl group with 1 to 12 carbon atoms such as tert-butyl and isopropyl, in particular, 1,3-bis[(di-tert-butylphosphino)oxy]benzene ((tBu)2P-O-C6H4-OP(tBu)2 );R'PNP = R'2PCH2CH2N(H)CH2CH2PR'2 where R' is an aryl group with 6 to 20 carbon atoms such as phenyl or an alkyl group with 1 to 12 carbon atoms such as tert-butyl and isopropyl, in particular, bis[2-diphenylphosphino)ethyl]amine {((C6H5)2P-CH2-CH2)2NH} and bis[2-di-isopropylphosphino)ethyl]amine {((CH3)2CH)2P-CH2-CH2)2NH] ; ;

[0031] - oxygenated bases such as acetate (CH3COO), acetylacetonate ([CH3 COCHCOCH3] ), the methanolate (CH3-O ), the ethoxide (CH3-CH2-O );

[0032] - carbon ligands chosen from CO, CN;

[0033] - halogens selected from Cl, Br, I;

[0034] - a hydrogen atom;

[0035] - N-heterocyclic carbenes derived from an imidazolium salt selected from the salts 1,3-bis(2,6-diisopropylphenyl)-lH-imidazol-3-ium, 1,3-bis(2,6-diisopropylphenyl)-4,5-dihydro-lH-imidazol-3-ium, 1,3-bis(2,4,6-trimethylphenyl)-lH-imidazol-3-ium, 1,3-bis(2,4,6-trimethylphenyl)-4,5-dihydro-1H-imidazol-3-ium, 4,5-dichloro-1,3-bis(2,6-düsopropylphenyl)-1H-imidazol-3-ium, 1,3-di-tert-butyl-1H-imidazol-3-ium, 1,3-di-tert-butyl-4,5-dihydro-lH-imidazol-3-ium,

[0036] or a mixture of these ligands,

[0037] the metallic complex possibly comprising a counter anion selected from PF6, BF4, CF3SO3 or OTf, • a boron compound comprising at least 3 substituents selected from a hydrogen atom, an alkyl group comprising 1 to 12 carbon atoms, a cycloalkyl group comprising 3 to 12 carbon atoms, an aryl group comprising 6 to 20 carbon atoms, a halogen selected from Cl, Br, I, or a mixture of these substituents, said alkyl, cycloalkyl and aryl groups being optionally substituted,

[0038] the boron complex possibly comprising a counter cation chosen from Li+, Na+, K+ or Mg2+, • a heterocyclic boron compound such as 9-borabicyclo[3.3.1]nonane or 9-BBN or one of its substituted derivatives such as 9-chloro-borabicyclo[3.3.1]nonane or C1-9-BBN, 9-iodo-borabicyclo[3.3.1]nonane or I-9-BBN, 9-triflate-borabicyclo[3.3.1]nonane or TfO-9-BBN • a (pseudo-)haloborane of formula (II) as defined above; and

[0039] (B) a nitrogenous or phosphorus base having a pKa between 5 and 50 in the DMSO or in acetonitrile chosen from

[0040] . a tertiary amine comprising an alkyl group having 1 to 12 atoms of carbon, a cycloalkyl group comprising 3 to 12 carbon atoms, an aryl group comprising 6 to 20 carbon atoms, in particular triethylamine (NEt3), N,N-diisopropylethylamine (DIPEA) and N,N-dicyclohexylmethylamine (Cy2NMe),

[0041] . a phosphazene in particular tert-butylimino-tri(pyrrolidino)phosphoane or BTPP,

[0042] . a proazaphosphatrane-type base, in particular the 2,8,9-triisopropyl-2,5,8,9-tetraaza-l-phosphabicyclo[3.3.3]undecane, 2,8,9-triisobutyl-2,5,8,9-tetraaza-1-phosphabicyclo[3.3.3]undecane, 2,8,9-trimethyl-2,5,8,9-tetraaza-l-phosphabicyclo[3.3.3]undecane; And

[0043] (C) in a solvent or a mixture of at least two solvent(s) selected from: • the ethers chosen from diethyl ether, THF, dioxane, anisole, and diglyme, • tertiary amines selected from triethylamine (NEt3), N,N-diisopropylethylamine (DIPEA) and N,N-dicyclohexylmethylamine (Cy 2NMe), • hydrocarbons and aromatics selected from benzene, toluene, xylene, pentane, hexane, cyclohexane, • Pyridine-based solvents chosen from lutidine, or 2,6-di-tert-butylpyridine, • alkyl halides selected from chloroform and methylene chloride, • aryl halides selected from chlorobenzene and dichlo- robenzène;

[0044] under hydrogen pressure between 0.1 bar and 300 bar.

[0045] The present invention proposes a new route for the synthesis of hydroboranes, which allows for a significant improvement in the energy balance of the reaction. Known processes for converting boron-chloride bonds into boron-hydrogen bonds require significant energy expenditure in their operation (temperature) and in the choice of reagents used (energy-intensive preparation methods, low energy efficiency). The process of the invention addresses the need to produce hydroboranes in an energy-efficient manner.

[0046] The present invention proposes a new synthetic route for hydroboranes leading to high yields and a wide range of targets of interest. Previously described synthetic routes result in low yields and significant boron losses in the form of waste. The present invention addresses the need to efficiently produce hydroboranes without significant boron losses.

[0047] The present invention proposes a new method for synthesizing hydroborane based on the activation of hydrogen by a catalyst and a base. Conventional methods for preparing hydroboranes rely essentially on borane (BH3) itself, prepared from pyrophoric reagents in stoichiometric quantities. The present invention addresses the need to produce hydroboranes more safely by reducing the quantity of hazardous reagents and their risk.

[0048] Another object of the invention is the use of the process of the invention

[0049] - in organic synthesis, for example, for the reduction of carbonyl functions or for the preparation of boronic ester by borylation reaction

[0050] - in inorganic synthesis, for example, in the production of industrial molecules such as methanol, formic acid, ammonia, etc.

[0051] - for the depolymerization of lignin, and

[0052] - for the depolymerization of oxygenated polymers such as polyethylene te- rephthalate (PET), polybutylene terephthalate (PBT), polytrimethylene terephthalate (PTT), polyethylene naphthalate (PEN), polylactic acid (PLA), polyglycolic acid (PGA), polycaprolactone (PCL), polycarbonate (PC-BPA), etc.

[0053] The invention also relates to the use of a process according to the invention for recycling (pseudo-)haloboranes from the corresponding hydroboranes. Brief description of the figures

[0054] Other features and advantages of the invention will become apparent upon reading the detailed description that follows, for an understanding of which reference should be made to the accompanying drawings in which:

[0055] [Fig-1] represents the industrial synthesis route of borane BH3.

[0056] [Fig.2] represents the substoichiometric hydrogenolysis of BC13 assisted by the lutidine described by Camaioni.

[0057] [Fig.3] represents a hydrogenolysis reaction of a bis-aryl chloroborane operationalized by 2,2,6,6-tetramethylpiperidine (TMP) groups to form the corresponding borane.

[0058] [Fig.4] represents a sigma bond metathesis reaction between a substituted boron by one or more halogens and / or oxygen groups (BX) and a water source, usually borane (BH3) or silanes.

[0059] [Fig. 5] represents the chemical structure of some of the compounds mentioned in the present exposed. Detailed description of the invention

[0060] The present invention relates to a process for preparing a hydroborane of formula (I)

[0061]

[0062] from a (pseudo-)haloborane of formula (II)

[0063] (RJ^R^BX,

[0064] in which

[0065] - Ri and R2, identical or different, are an alkyl group comprising 1 to 12 atoms of carbon, a cycloalkyl group comprising 3 to 12 carbon atoms, an aryl group comprising 6 to 20 carbon atoms, an alkoxy group whose alkyl group comprises 1 to 12 carbon atoms, a cycloalkoxy (-O-cycloalkyl) group whose cycloalkyl group comprises 3 to 12 carbon atoms, an aryloxy group whose aryl group comprises 6 to 20 carbon atoms, an -NR3R4 group, with R3 and R4, identical or different, representing a hydrogen atom, an alkyl group comprising 1 to 12 carbon atoms, a cycloalkyl group comprising 3 to 12 carbon atoms, an aryl group comprising 6 to 20 carbon atoms, said alkyl and cycloalkyl groups being optionally substituted; or

[0066] - Ri and R2 taken together with the boron atom to which they are bonded, form a he- heterocycle comprising 5 to 12 members, said heterocycle group possibly being substituted;

[0067] -n is 1,2, 3;

[0068] - m is 0, 1;

[0069] - o is 0, 1;

[0070] - X represents Cl, Br, I, -SO2R with R being a -CF3, -CH3 or o-tolyl, m- group tolyle, p-tolyle;

[0071] characterized in that the (pseudo-)haloborane of formula (II) is brought into contact with

[0072] (A) a catalyst selected from • a metallic complex in which the metal is a transition metal chosen from chromium, tungsten, manganese, rhenium, silver, rhodium, cobalt, iron, nickel, copper, iridium, ruthenium, osmium, molybdenum, gold, platinum and palladium, and the ligands linked to the transition metals are chosen from:

[0073] - nitrogenous bases such as tertiary amines selected from the 4-Dimethylaminopyridine (DMAP), 1,4-diazabicyclo[2.2.2]octane (DABCO), N-diisopropylethylamine (DIPEA or DIEA), bipyridyl (bipy), terpyridine (terpy); phenantroline (phen), ethylenediamine, A,A,A',A'-tetramethylethylenediamine (TMEDA), quinoline and pyridine;

[0074] - phosphorus bases such as alkyl and aryl phosphines chosen from the tri- phenylphosphine, 2,2'-bis(diphenylphosphino)-l,r-binaphthyl (BINAP), triiso-propylphosphine, tris[2-diphenylphosphino)ethyl]phosphine (PP3), 4,5-bis-(di-i-propylphosphinomethyl)acridine, 4,5-bis-(di-phenylphosphinomethyl)acridine, tricyclohexylphosphine, 1,2-bis-diphenylphosphinoethane (dppe), 1,2-bis(diphenylphosphino)ethane (dppb); SPOCOP = (C6H4){ 1,3-OPR2}2) where R is an aryl group with 6 to 20 carbon atoms such as phenyl or an alkyl group with 1 to 12 carbon atoms such as tert-butyl and isopropyl, in particular, 1,3-bis[(di-tert-butylphosphino)oxy]benzene ((tBu)2P-O-C6H4-OP(tBu)2 );R'PNP = R'2PCH2CH2N(H)CH2CH2PR'2 where R' is an aryl group with 6 to 20 carbon atoms such as phenyl or an alkyl group with 1 to 12 carbon atoms such as tert-butyl and isopropyl, in particular, bis[2-diphenylphosphino)ethyl]amine {((C6H5)2P-CH2-CH2)2NH] and bis[2-di-isopropylphosphino)ethyl]amine {((CH3)2CH)2P-CH2-CH2)2NH] ; ;

[0075] - oxygenated bases such as acetate (CH3COO), acetylacetonate ([CH3 COCHCOCH3] ), the methanolate (CH3-O ), the ethoxide (CH3-CH2-O );

[0076] - carbon ligands chosen from CO, CN;

[0077] - halogens selected from Cl, Br, I;

[0078] - a hydrogen atom;

[0079] - N-heterocyclic carbenes derived from an imidazolium salt selected from the salts 1,3-bis(2,6-diisopropylphenyl)-1H-imidazol-3-ium, 1,3-bis(2,6-düsopropylphenyl)-4,5-dihydro-1H-imidazol-3-ium, 1,3-bis(2,4,6-trimethylphenyl)-1H-imidazol-3-ium, 1,3-bis(2,4,6-trimethylphenyl)-4,5-dihydro-1H-imidazol-3-ium, 4,5-dichloro-1,3-bis(2,6-düsopropylphenyl)-1H-imidazol-3-ium, 1,3-di-tert-butyl-1H-imidazol-3-ium, 1,3-di-tert-butyl-4,5-dihydro-1H-imidazol-3-ium,

[0080] or a mixture of these ligands,

[0081] the metal complex optionally comprising a counter-anion selected from PF6, BF4, CF3SO3 or OTf, • a boron compound comprising at least 3 substituents selected from a hydrogen atom, an alkyl group comprising 1 to 12 carbon atoms, a cycloalkyl group comprising 3 to 12 carbon atoms, an aryl group comprising 6 to 20 carbon atoms, a halogen selected from Cl, Br, I, or a mixture of these substituents, said alkyl, cycloalkyl and aryl groups being optionally substituted,

[0082] the boron complex possibly comprising a counter cation selected from Li+, Na+, K+ or Mg2+, • a heterocyclic boron compound such as 9-borabicyclo[3.3.1]nonane or 9-BBN or one of its substituted derivatives such as 9-chloro-borabicyclo[3.3.1]nonane or C1-9-BBN, 9-iodo-borabicyclo[3.3.1]nonane or I-9-BBN, 9-triflate-borabicyclo[3.3.1]nonane or TfO-9-BBN, • a (pseudo-)haloborane of formula (II) as defined above; and

[0083] (B) a nitrogenous or phosphorus base having a pKa between 5 and 50 in the DMSO or in acetonitrile chosen from

[0084] . a tertiary amine comprising an alkyl group having 1 to 12 atoms of carbon, a cycloalkyl group comprising 3 to 12 carbon atoms, an aryl group comprising 6 to 20 carbon atoms, in particular triethylamine (NEt3), N,N-diisopropylethylamine (DIPEA) and N,N-dicyclohexylmethylamine (Cy2NMe),

[0085] . a phosphazene in particular tert-butylimino-tri(pyrrolidino)phosphoane or BTPP,

[0086] . a proazaphosphatrane-type base, in particular the 2,8,9-triisopropyl-2,5,8,9-tetraaza-l-phosphabicyclo[3.3.3]undecane, 2,8,9-triisobutyl-2,5,8,9-tetraaza-l-phosphabicyclo[3.3.3]undecane, 2,8,9-Trimethyl-2,5,8,9-tetraaza-l-phosphabicyclo[3.3.3]undecane; and

[0087] (C) in a solvent or a mixture of at least two solvent(s) selected from: • the ethers chosen from diethyl ether, THF, dioxane, anisole, and diglyme, • tertiary amines selected from triethylamine (NEt3), the N,N-düsopropylethylamine (DIPEA) and N,N-dicyclohexylmethylamine (Cy 2NMe), • hydrocarbons and aromatics selected from benzene, toluene, xylene, pentane, hexane, cyclohexane, • Pyridine-based solvents chosen from lutidine, or 2,6-di-tert-butylpyridine, • alkyl halides selected from chloroform and methylene chloride, • aryl halides selected from chlorobenzene and dichlo-robenzene;

[0088] under hydrogen pressure between 0.1 bar and 300 bar.

[0089] The hydrogenolysis of the BX functional group is based on two distinct steps. 1) The catalyst / base pair must allow the cleavage of the hydrogen's HH bond via a frustrated Lewis pair (FLP) mechanism. 2) The intermediately formed catalytic species [catalystH] must exhibit sufficient hydric character to transfer a hydride to the (pseudo-)haloborane substrate. The process of the invention relies on the judicious and non-obvious selection of the elements of the catalyst / base pair to allow each of these steps without inhibiting the reactivity of the other. Excessive or insufficient acidic and basic Lewis character inhibit the reaction by preventing hydrogen activation. Similarly, excessively acidic Lewis character will prevent hydride transfer during the second step.

[0090] Thermodynamics shows that this hydrogenolysis reaction of (pseudo-)haloborane to hydroborane is unfavorable. The Gaussian DFT (density functional theory) calculation of the transformation of Cy2BCl to Cy2BH in the presence of triethylamine and hydrogen shows a positive Gibbs free energy of +10.3 kcal / mol.

[0091] The synthesis of (pseudo-)haloborane derivative (BX) is reported by adding the corresponding acid (XH) to hydroborane (BH) with hydrogen evolution (HC Brown et al., Journal of Organometallic Chemistry, 1979,168 (3), 281-293; HC Brown et al., J. Org. Chem., 1993, 58 (1), 147-153). The process of the invention, which is the reverse reaction to that reported in the literature, then appears counterintuitive to a person skilled in the art.

[0092] The present invention makes it possible to produce hydroboranes from (pseudo-)haloboranes under milder conditions than those reported in the literature, i.e. with a lower energy input (thermal and chemical), greater selectivity towards the products formed, while reducing the danger of the reagents used.

[0093] For the purposes of the invention, "borane" means a boron-based molecule exhibiting BH and / or BC bonds.

[0094] For the purposes of the invention, the term "hydroborane" refers to boranes specifically exhibiting one or more BH bonds.

[0095] For the purposes of the invention, the term "haloborane" refers to boranes specifically having one or more β-halogen bonds, the halogen being F, Cl, Br or I.

[0096] For the purposes of the invention, the term “pseudo-haloborane” refers to boranes linked to one or more groups which are not halogens but which behave like halogens such as, for example, the group -OSO2CF3 or -OTf.

[0097] In the context of the present invention, "alkyl" means, as defined herein, a linear, branched, and saturated carbon radical, optionally substituted, comprising 1 to 12 carbon atoms. In some cases, the alkyl may comprise, for example, 1 to 10 carbon atoms, 1 to 8 carbon atoms, or 1 to 6 carbon atoms. Examples of saturated alkyl radicals, whether linear or branched, include, for example, the methyl, ethyl, propyl, butyl, pentyl, hexyl, octyl, nonyl, decyl, undecyl, and dodecyl radicals and their branched isomers.

[0098] For the purposes of this invention, "cycloalkyl" means a saturated, optionally substituted, mono- or poly-cyclic carbon radical comprising 3 to 12 carbon atoms. In some cases, the alkyl may comprise, for example, 3 to 10 carbon atoms, or for example, 5 to 10 carbon atoms. Examples of cyclic alkyl radicals include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, bicyclo[2,1,1]hexyl, bicyclo[2,2,1]heptyl, bicyclo[3,3,1]nonane, adamantyl, and isopinocampheyl.

[0099] The alkyl and cycloalkyl groups may optionally be substituted by one or more alkoxy groups; one or more aryloxy groups; one or more halogens selected from the atoms of fluorine, chlorine, bromine or iodine; one or more nitro groups (-NO2); one or more nitrile groups (-CN); one or more aryl groups; one or more trifluoromethyl groups (-CF3); with the alkoxy and aryl groups as defined within the scope of the present invention.

[0100] The term "aryl" refers to a mono- or polycyclic aromatic substituent comprising from 6 to 20 carbon atoms. The aryl group may comprise, for example, 6 to 10 carbon atoms, or 6 to 8 carbon atoms. The aryl group may comprise, for example, 6 carbon atoms. In the context of the invention, the aryl group may be mono- or polycyclic. By way of example, the following groups may be mentioned: phenyl, benzyl, naphthyl, o-tolyl, m-tolyl, p-tolyl, mesityl, p-nitrophenyl, o-methoxyphenyl, m-methoxyphenyl, p-methoxyphenyl, o-methoxybenzyl, p-methoxybenzyl, m-methoxybenzyl, o-methylbenzyl, p-methylbenzyl, and m-methylbenzyl. The aryl group may optionally be substituted by one or more alkoxy groups; one or more aryloxy groups; one or more halogens selected from the atoms of fluorine, chlorine, bromine and iodine; one or more nitro groups (-NO2); one or more nitrile groups (-CN); one or more trifluoromethyl groups (-CF3); one or more alkyl groups, with the alkoxy and alkyl groups as defined within the scope of the present invention.

[0101] The term "alkoxy" means an alkyl group, as defined above, linked by an oxygen atom (-O-alkyl).

[0102] The term "cycloalkoxy" means a cycloalkyl group, as defined above, linked by an oxygen atom (-O-cycloalkyl).

[0103] The term "aryloxy" means an aryl group, as defined above, linked by an oxygen atom (-O-aryl).

[0104] By "halogen" is meant a substituent selected from the atoms of fluorine, chlorine, bromine and iodine or in the form of an anion (also called a halide) selected from F, Cl, Br and I.

[0105] The term "heterocycle" or "heterocyclic" designates a mono- or polycyclic group or substituent, comprising from 5 to 12 members, for example 5 to 10 members, saturated or unsaturated, and containing from 1 to 3 identical or different heteroatoms, selected from nitrogen, oxygen and / or boron. By way of example, catecholboranyl or CatB-, 9-borabicyclo[3.3.1]nonanyl or 9-BBN, pinacolboranyl or -Bpin may be cited.

[0106] The heterocycles may optionally be substituted by one or more alkoxy (-O-alkyl) groups; one or more aryloxy (-O-aryl) groups; one or more halogens selected from fluorine, chlorine, bromine and iodine; one or more nitro (-NO2) groups; one or more nitrile (-CN) groups; one or more trifluoromethyl (-CF3) groups; one or more alkyl groups or radicals; one or more aryl groups or radicals; with alkyl and aryl as defined within the scope of the present invention.

[0107] For the purposes of this invention, "catalyst" means any compound capable of causing a reaction simply by its presence or intervention. It can also modify, particularly by increasing, the rate of the chemical reaction in which it participates. The catalyst is regenerated at the end of the reaction and does not appear in the overall reaction balance. This definition encompasses catalysts, that is, compounds that exert their catalytic activity without needing to undergo any modification or conversion, and compounds (also called precatalysts) that are introduced into the reaction medium and converted into a catalyst therein.

[0108] By “yield” we mean the ratio between the quantity of product obtained and the maximum quantity that would be obtained if the reaction were complete.

[0109] It should be noted that in all compounds, substituents, radicals, groups and groups, solvents, reagents, etc. cited and / or defined in the context of the present invention, one or more hydrogen atoms may be, optionally, replaced by one or more deuterium (2H).

[0110] Examples of deuterated solvents include THF-d8, benzene-d6, toluene-d8, cyclohexane-dl2, methylene chloride-d2, chlorobenzene-d5, and CDC13. This list is not exhaustive.

[0111] According to a first embodiment, in the process of the invention, Ri and R2, identical or different, can represent a hydrogen atom, an alkyl group comprising 1 to 12 carbon atoms, a cycloalkyl group comprising 3 to 12 carbon atoms, an aryl group comprising 6 to 20 carbon atoms, said alkyl, cycloalkyl and aryl groups being optionally substituted.

[0112] Preferably, in this embodiment, Ri and R2, identical or different, represent a hydrogen atom, an alkyl group comprising 1 to 10 carbon atoms, a cycloalkyl group comprising 5 to 10 carbon atoms, an aryl group comprising 6 to 10 carbon atoms, said alkyl, cycloalkyl and aryl groups being optionally substituted.

[0113] More preferably, Ri and R2, identical or different, are a hydrogen atom, cyclohexyl, bicyclo[2,l,l]hexyl, bicyclo[2,2,1]heptyl, bicyclo[3.3.1]nonane, isopinocampheyl, phenyl, benzyl, naphthyl, o-tolyl, m-tolyl, p-tolyl.

[0114] According to a second embodiment, in the process of the invention, Ri and R2 taken together with the boron atom to which they are linked, form a heterocycle comprising 5 to 12 members, said heterocycle group being optionally substituted.

[0115] Preferably, in this embodiment, Ri and R2 taken together with the boron atom to which they are bonded, form a heterocycle comprising 5 to 10 members, the heterocycle being optionally substituted.

[0116] More preferably, Ri and R2 taken together with the boron atom to which they are bonded, form a catecholboranyl or CatB-, 9-borabicyclo[3.3.1] nonanyl or 9-BBN, pinacolboranyl or -Bpin.

[0117] In all embodiments and variants of the invention, X represents Cl, Br, I , -oso2r with R being a group -CF3, -CH3 or o-tolyle, m-tolyle, p-tolyle.

[0118] In all embodiments and variants of the invention,

[0119] - n is 1, 2, 3;

[0120] - m is 0, 1;

[0121] - o is 0, 1.

[0122] According to a third embodiment, the catalyst (A) is chosen from a metal complex whose metal is a transition metal chosen from manganese, iron, cobalt, iridium, rhodium, rhenium, and ruthenium, and the Transition metal-bound ligands are chosen from:

[0123] - nitrogenous bases such as 4-dimethylaminopyridine (DMAP), the 1,4-Diazabicyclo[2.2.2]octane (DABCO), bipyridyl (bipy), terpyridine (terpy); phenantroline (phen), ethylenediamine, A,A,A',A'-tetramethylethylenediamine (TMEDA), quinoline and pyridine,

[0124] - phosphorus bases such as alkyl and aryl phosphines selected from the tri- phenylphosphine, 2,2'-bis(diphenylphosphino)-l,r-binaphthyl (BINAP), triiso-propylphosphine, tris[2-diphenylphosphino)ethyl]phosphine (PP3), tricyclohexylphosphine, 4,5-bis-(di-i-propylphosphinomethyl)acridine, 4,5-bis(diphenylphosphino)acridine, 1,2-bis-diphenylphosphino ethane (dppe), 1,2-bis(diphenylphosphino) ethane (dppb); / BuPOCOP = (C6H3){ l,3-OPtBu2}2), phPNP = Ph2PCH2CH2N(H)CH2CH2PPh2'PlPNP = iPr2PCH2CH2N(H)CH2CH2PiPr2,

[0125] - carbon ligands selected from CO, CN,

[0126] - halogens selected from Cl, Br, I,

[0127] - a hydrogen atom,

[0128] or a mixture of these ligands.

[0129] According to a preferred embodiment, the catalyst (A) is chosen from a metal complex in which the metal is iridium or ruthenium, and the transition metal-bound ligands are chosen from:

[0130] - phosphorus bases such as / BuPOCOP = (C6H3){ l,3-OPtBu2}2); the 4,5-bis-(di-i-propylphosphinomethyl)acridine, 4,5-bis(diphenylphosphino)acridine,

[0131] - carbon ligands such as CO,

[0132] - halogens selected from Cl, Br, I,

[0133] - a hydrogen atom,

[0134] or a mixture of these ligands.

[0135] According to an even more preferred variant of this embodiment, the catalyst (A) ruthenium chlorocarbonylhydrido[4,5-bis-(di-iso-propyl phosphinomethyl)acridine], [Ir( / BuPOCOP)HCl].

[0136] According to a fourth embodiment, the catalyst (A) is a boron compound comprising at least 3 substituents, selected from a hydrogen atom, an alkyl group comprising 1 to 12 carbon atoms, a cycloalkyl group comprising 3 to 12 carbon atoms, an aryl group comprising 6 to 20 carbon atoms, a halogen selected from Cl, Br, I, or a mixture of these substituents, said alkyl, cycloalkyl and aryl groups being optionally substituted.

[0137] According to a variant of this embodiment, the catalyst (A) is a boron compound comprising 4 substituents, one being a hydrogen atom while the other 3 substituents are chosen from

[0138] - a hydrogen atom,

[0139] - an alkyl group comprising 1 to 12 carbon atoms, in particular ethyl, the propyl, isopropyl, butyl and isobutyl,

[0140] - a cycloalkyl group comprising 5 to 10 carbon atoms, in particular cy- clohexyl, bicyclo[2,l,l] hexyl, bicyclo[2,2,l] heptyl, bicyclo[3.3.1]nonane, isopinocampheyl,

[0141] - an aryl group comprising 6 to 20 carbon atoms, in particular phenyl (-Ph) and pentafluorophenyl (-C6F5),

[0142] a halogen selected from Cl, Br, I, or a mixture of these substituents. In this variant the catalyst comprises a counter cation selected from Li+, Na+, K+.

[0143] According to an even more preferred variant of this embodiment, the catalyst (A) is potassium triethylborohydride or KET3BH.

[0144] According to another variant of this embodiment, the catalyst (A) is a boron compound comprising 3 substituents selected from

[0145] - a hydrogen atom,

[0146] - an alkyl group comprising 1 to 12 carbon atoms, in particular ethyl, the propyl, isopropyl, butyl and isobutyl,

[0147] - a cycloalkyl group comprising 5 to 10 carbon atoms, in particular cy- clohexyl, bicyclo[2,l,l] hexyl, bicyclo[2,2,l] heptyl, bicyclo[3.3.1]nonane, isopinocampheyl,

[0148] - an aryl group comprising 6 to 20 carbon atoms, in particular phenyl (Ph) and pentafluorophenyl (-CgFj),

[0149] - a halogen selected from Cl, Br, I,

[0150] or a mixture of these substituents.

[0151] According to a preferred variant of this other variant of this embodiment, the catalyst (A) is dicyclohexylborane or Cy2BH, chlorodicyclohexylborane or Cy2 BC1, bis(bicyclo[2,2,l]-2-heptyl)chloroborane, chloro-diisopinocampheylborane or Cl-DIP, triphenylborane or BPh3.

[0152] According to a more preferred variant of this other variant of this embodiment, the catalyst (A) is dicyclohexylborane or Cy2BH.

[0153] According to another more preferred variant of this other variant of this embodiment, the catalyst (A) is triphenylborane or BPh3.

[0154] According to a fifth embodiment, the catalyst (A) is a borane of formula (I) in which

[0155] - Ri and R2, identical or different, represent an alkyl group comprising 1 to 12 carbon atoms, a cycloalkyl group comprising 3 to 12 carbon atoms, said alkyl, cycloalkyl groups possibly being substituted;

[0156] - n is 1, 2, 3;

[0157] - m is 0, 1;

[0158] - o is 0, 1.

[0159] According to a preferred embodiment of this incarnation, the catalyst (A) is a borane of formula (I) in which

[0160] - Ri and R2, identical or different, are a cycloalkyl group comprising 5 to 10 carbon atoms including cyclohexyl, bicyclo[2,l,l]hexyl, bicyclo[2,2,1]heptyl, bicyclo[3.3.1]nonane, isopinocampheyl, said cycloalkyl group possibly being substituted;

[0161] - n is 1, 2, 3;

[0162] - m is 0, 1;

[0163] - o is 0, 1.

[0164] According to an even more preferred variant of this embodiment, the catalyst (A) is dicyclohexylborane or Cy2BH.

[0165] According to a sixth embodiment, the catalyst (A) is a (pseudo-)haloborane of formula (II) in which

[0166] - Ri and R2, identical or different, represent an alkyl group comprising 1 to 12 carbon atoms, a cycloalkyl group comprising 3 to 12 carbon atoms, said alkyl, cycloalkyl groups possibly being substituted;

[0167] -n is 1,2, 3;

[0168] - m is 0, 1;

[0169] - o is 0, 1;

[0170] - X represents Cl, Br, I, -OSO2R with R being a -CF3, -CH3 or o-tolyl, m- group tolyle, p-tolyle.

[0171] According to a preferred embodiment of this incarnation, the catalyst (A) is a (pseudo-)haloborane of formula (II) in which

[0172] - Ri and R2, identical or different, are a cycloalkyl group comprising 5 to 10 carbon atoms including cyclohexyl, bicyclo[2,1,1]hexyl, bicyclo[2,2,1]heptyl, bicyclo[3.3.1]nonane, isopinocampheyl, said cycloalkyl group possibly being substituted;

[0173] -n is 1,2, 3;

[0174] - m is 0, 1;

[0175] -o is 0.1;

[0176] - X represents Cl, Br, I, -OSO2R with R being a -CF3, -CH3 or o-tolyl, m- group tolyle, p-tolyle.

[0177] According to an even more preferred variant of this embodiment, the catalyst (A) is chlorodicyclohexylborane or Cy2BCl, dicyclohexylborane triflate, chloro-diisopinocampheylborane or Cl-DIP, bis(bicyclo[2,2,l]-2-heptyl)chloroborane.

[0178] According to a seventh embodiment, the catalyst (A) is a borane of formula (I) in which

[0179] - Ri and R2 taken together with the boron atom to which they are bonded, form a he- heterocycle comprising 5 to 12 members, said heterocycle group possibly being substituted;

[0180] -n is 1,2, 3;

[0181] - m is 0, 1;

[0182] -o is 0.1.

[0183] According to a preferred embodiment of this design, the catalyst (A) is a borane of formula (I) in which

[0184] - Ri and R2 taken together with the boron atom to which they are bonded, form a he heterocycle comprising 5 to 10 members including 9-borabicyclo[3.3.1]nonanyl or 9-BBN, said heterocycle group possibly being substituted;

[0185] - n is 1, 2, 3;

[0186] - m is 0, 1;

[0187] -o is 0.1.

[0188] According to an even more preferred variant of this embodiment, the catalyst (A) is 9-borabicyclo[3.3.1]nonane or 9-BBN.

[0189] According to an eighth embodiment, the catalyst (A) is a (pseudo-)haloborane of formula (II) in which

[0190] - Ri and R2 taken together with the boron atom to which they are bonded, form a he heterocycle comprising 5 to 12 members, said heterocycle group possibly being substituted;

[0191] - n is 1, 2, 3;

[0192] - m is 0, 1;

[0193] - o is 0, 1;

[0194] - X represents Cl, Br, I, -OSO2R with R being a -CF3, -CH3 or o-tolyl, m- group tolyle, p-tolyle.

[0195] According to a preferred embodiment of this incarnation, the catalyst (A) is a (pseudo-)haloborane of formula (II) in which

[0196] - Ri and R2 taken together with the boron atom to which they are bonded, form a he heterocycle comprising 5 to 10 members, including catecholboranyl or CatB-, 9-borabicyclo[3.3.1]nonanyl or 9-BBN, pinacolboranyl or -Bpin, said heterocycle group possibly being substituted;

[0197] -n is 1,2, 3;

[0198] - m is 0, 1;

[0199] - o is 0, 1;

[0200] - X represents Cl, Br, I, -OSO2R with R being a -CF3, -CH3 or o-tolyl, m- group tolyle, p-tolyle.

[0201] According to an even more preferred variant of this embodiment, the catalyst (A) is 9-borabicyclo[3.3.1]nonane or 9-BBN, 9-chloro-borabicyclo[3.3.1]nonane or C1-9-BBN, 9-triflate-borabicyclo[3.3.1]nonane or TfO-9-BBN.

[0202] In all embodiments and variants of the invention, the amount of catalyst used in the process of the invention is from 0.1 to 100% molar, preferably from 0.1 to 10% molar, more preferably from 2 to 10% molar, relative to (pseudo-)haloborane of formula (II).

[0203] According to a ninth embodiment, the base (B) is a nitrogenous or phosphorus base having a pKa between 5 and 50 in DMSO or in acetonitrile chosen from

[0204] . a tertiary amine comprising an alkyl group having 1 to 12 atoms of carbon, a cycloalkyl group comprising 3 to 12 carbon atoms, an aryl group comprising 6 to 20 carbon atoms, notably triethylamine (NEt3), N,N-diisopropylethylamine (DIPEA) and N,N-dicyclohexylmethylamine (Cy2NMe),

[0205] . a phosphazene in particular terLbutylimino-tri(pyrrolidino)phosphorane or BTPP,

[0206] . a proazaphosphatrane-type base, in particular the 2,8,9-triisopropyl-2,5,8,9-tetraaza-l-phosphabicyclo[3.3.3] undecane, 2,8,9-triisobutyl-2,5,8,9-tetraaza-1 -phosphabicyclo [3.3.3] undecane.

[0207] According to a preferred embodiment of this embodiment, the base (B) is a tertiary amine comprising an alkyl group having 1 to 8 carbon atoms, a cycloalkyl group having 5 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, in particular triethylamine (NEt3), N,N-diisopropylethylamine (DIPEA) and N,N-dicyclohexylmethylamine (Cy2NMe).

[0208] In all embodiments and variants of the invention, the amount of base used in the process of the invention is from 1 to 30 equivalents, preferably to 20 equivalents, more preferably from 1 to 2 equivalents, relative to the number of BX bonds to be hydrogenated. The base may also be used in excess, particularly when used as the reaction solvent.

[0209] The preparation of a hydroborane of formula (I) from a (pseudo-)haloborane of formula (II) takes place in a solvent or a mixture of at least two solvent(s) (C), preferably chosen from: • the ethers chosen from diethyl ether, THF, dioxane, anisole, and diglyme, • amines selected from triethylamine (NEt3), N,N-diisopropylethylamine (DIPEA) and N,N-dicyclohexylmethylamine (Cy2NMe), • Pyridine-based solvents such as lutidine, • hydrocarbons and aromatics selected from benzene, toluene, the xylene, pentane, hexane, cyclohexane, • alkyl halides selected from chloroform and methylene chloride, • Aryl halides selected from chlorobenzene and dichlorobenzene.

[0210] In solution, the concentration of (pseudo-)haloborane of formula (II) is between between 0.01 and 10M, preferably 0.05 and 5M, more preferably 0.1M and IM.

[0211] Preferably, the preparation of a hydroborane of formula (I) from a (pseudo-)haloborane of formula (II) takes place at a hydrogen pressure between 1 and 50, 1 bar and 15 bar. According to a preferred embodiment of the invention, the hydrogen pressure is 10 bar.

[0212] The preparation temperature of a hydroborane of formula (I) from a (pseudo-)haloborane of formula (II) according to the process of the invention is between -78°C and 150°C, preferably between 0 and 30°C. According to a preferred embodiment of the invention, the temperature is 25°C.

[0213] The duration of the reaction depends on the conversion rate of (pseudo-)haloborane of formula (II) to hydroborane of formula (I). The reaction is advantageously maintained until the complete conversion of (pseudo-)haloborane. The duration of the reaction can thus be from 1 to 300 hours, preferably from 5 to 270 hours.

[0214] Another object of the invention is the use of the process of the invention

[0215] - in organic synthesis, for example, for the reduction of carbonyl functions or for the preparation of boronic ester by borylation reaction

[0216] - in inorganic synthesis, for example, in the production of industrial molecules such as methanol, formic acid, ammonia, etc.

[0217] - for the depolymerization of lignin, and

[0218] - for the depolymerization of oxygenated polymers such as polyethylene te- rephthalate (PET), polybutylene terephthalate (PBT), polytrimethylene terephthalate (PTT), polyethylene naphthalate (PEN), polylactic acid (PLA), polyglycolic acid (PGA), polycaprolactone (PCL), polycarbonate (PC-BPA), etc.

[0219] The application of the process of the invention is integrated into recycling processes for (pseudo-)haloboranes derived from the use of the corresponding hydroboranes. Thus, the present invention also relates to the use of the process of the invention for the recycling of (pseudo-)haloboranes derived from the corresponding hydroboranes. EXAMPLES General operating procedure

[0220] All reactions are carried out under a strict atmosphere of ultrapure argon (< 5 ppm of dioxygen or water), using Schlenk-type glassware and associated vacuum ramp techniques, or an MBraun LabMaster DP type glove box. Glassware is dried for at least 2 hours at 60°C for NMR tubes and 120°C for the rest, or else dried with a flame just before use. The various products used were purchased from Sigma Aldrich with the exception of the deuterated solvents purchased from Eurisotop, the die- and clohexylmethyl lamine purchased from Fischer, the ruthenium chlorocarbo-nylhydrido[4,5-bis-(di-i-propylphosphino methyl)acridine] purchased from STREM, the B-C1-9-BBN synthesized in the laboratory from 9-BBN and HCl in diethyl ether according to the literature (Brown, HC et al., J. Organomet. Chem., 1979, 168 (3), 281-293), the [Ir( / BuPOCOP)HCl] synthesized in the laboratory according to the literature (M. Brookhart et al., Journal of American Chemical Society, 2004, 126 (6), 1804-1811). The solvents are dried by standard methods, and are distilled immediately before use or stored on a 4 Å molecular sieve. Said molecular sieve is dried under vacuum at 150°C for 24h before use.All reagents are dried or degassed before use, if necessary. Dihydrogen is used from an Air Products Hydrogen Premium Plus cylinder (< 1 ppm of dioxygen or water).

[0221] Most of the reactions in this project were carried out in New Era NMR tubes (maximum 20 bar). After the reagents and solvents were introduced into these tubes in the glove box, the reactions required a hydrogen atmosphere. The tubes were then degassed (to remove all the argon) by three freeze / vacuum cycles. At room temperature, the gas was introduced and the reaction was run on a tube turner made in the laboratory, or placed in an oil bath, or on a dedicated heating block, if the reaction was carried out at a higher temperature.

[0222] Small-volume autoclaves (4 mL max of reaction medium) allow work to be carried out on a larger scale than in NMR tubes. The reactors are made of stainless steel (SS316). The structure consists of two parts: a connection section (the head), made of commercial components purchased from Swagelok France; and another part, the reactor itself, manufactured by our laboratory.

[0223] A large part of the experiments that must be carried out under an inert atmosphere are done using a "simple" vacuum ramp. This ramp is used only in the presence of a good or even excellent vacuum (8x10 1 mbar max, 2x10 1 mbar min), in the absence of leaks (good vacuum maintenance in static mode for Ih).

[0224] The NMR spectra of the elements 'H, HB, 13C, 19F, 29Si and 31P are acquired via a Bruker AVANCE Neo 400 MHz spectrometer at 25°C.

[0225] In a pressure-resistant reactor conditioned under an inert atmosphere (argon, nitrogen), the catalyst (Xi mol%), the base (X2 equivalents), the solvent, and the (pseudo-)haloborane (x mol / L) are added. The reactor atmosphere is removed and replaced with hydrogen at the chosen pressure. The mixture is stirred for a specified time at a specified temperature.

[0226] The conversion of (pseudo-)haloboranes is monitored by HB and 'H NMR and can be quantified by titration of the product after reaction with an alkene or alkyne.

[0227] The hydrogenolysis products of (pseudo-)haloboranes can be obtained pure or can be purified, for example by recrystallization in a suitable solvent. Those skilled in the art can determine the recrystallization conditions. Example 1:

[0228] β-Chlorocatecholborane (0.1 mmol, 1 eq.), chlorodicyclohexylborane (0.01 mmol, 10 mol%), triethylamine (0.21 mmol, 2.1 eq.), and benzene (0.3 mL) are introduced into a New Era NMR tube under an inert atmosphere. The inert atmosphere is removed, and the tube is charged with hydrogen (10 bar). The mixture is stirred for 11 days at room temperature (20 ± 5°C). A yield of 68% catecholborane, determined by NMR, is obtained. Example 2:

[0229] Dichlorophenylborane (0.1 mmol, 1 eq.), chlorodicyclohexylborane (0.01 mmol, 10 mol%), triethylamine (0.21 mmol, 2.1 eq.), and d6 benzene (0.3 mL) are introduced into a New Era NMR tube under an inert atmosphere. The inert atmosphere is removed, and the tube is charged with hydrogen (10 bar). The mixture is stirred for 5 days at room temperature (20 ± 5°C). A yield of greater than 99% of PhBHCl, determined by NMR, is obtained. Example 3:

[0230] Boron trichloride in toluene solution (IM, 100pL, 0.1 mmol), chlorodicyclohexylborane (0.01 mmol, 10%), triethylamine (0.2 mmol, 2 eq.), and benzene (0.3 mL) are introduced into a New Era NMR tube under an inert atmosphere. The inert atmosphere is removed, and the tube is charged with hydrogen (10 bar). The mixture is heated to 120°C for 4 days. A yield of over 62% of BHC12, determined by NMR, is obtained. Example 4:

[0231] Dichlorophenyl borane (0.1 mmol, 1 eq.), 9-borabicyclo[3.3.1]nonane (0.01 mmol, 10 mol%), triethylamine (0.3 mmol, 3 eq.), and benzene (0.3 mL) are introduced into a New Era NMR tube under an inert atmosphere. The inert atmosphere is removed, and the tube is charged with hydrogen (10 bar). The mixture is heated at 80°C for 9 days. Yields of 45% for PhBH2 and 54% for PhBClH, determined by NMR, are obtained as a mixture. Example 5:

[0232] β-Chlorocatecholborane (0.1 mmol, 1 eq.), [Ir(tBuPOCOP)HCl] (0.002 mmol, 2 mol%), triethylamine (0.2 mmol, 2 eq.), and benzene (0.3 mL) are introduced into a New Era NMR tube under an inert atmosphere. The inert atmosphere is removed and The tube is charged with hydrogen (10 bar). The mixture is stirred for 4 days at room temperature (20 ± 5°C). A yield of 24% catecholborane, determined by NMR, is obtained. Example 6:

[0233] β-Chlorocatecholborane (0.1 mmol, 1 eq.), chlorocarbonylhydrido[4,5-bis-(di-i-propylphosphinomethyl)acridine]ruthenium(II) (0.005 mmol, 5 mol%), triethylamine (0.2 mmol, 2 eq.), and benzene (0.3 mL) are introduced into a New Era NMR tube under an inert atmosphere. The inert atmosphere is removed, and the tube is charged with hydrogen (10 bar). The mixture is heated to 80°C for 6 days. A yield of 21% catecholborane, determined by NMR, is obtained. Example 7:

[0234] 9-Iodo-9-borabicyclo[3.3.1]nonane in hexane solution (IM, 100pL, 0.1 mmol, 1 eq), [Ir(tBuPOCOP)HCl] (0.01 mmol, 10 mol%), dicyclohexylmethylamine (0.2 mmol, 2 eq), and benzene (0.3 mL) are introduced into a New Era NMR tube under an inert atmosphere. The inert atmosphere is removed, and the tube is charged with hydrogen (10 bar). The mixture is heated at 80°C for 4 days. The excess hydrogen is removed, and the 9-borabicyclo[3.3.1]nonane formed is titrated by reaction with 4-octyne (0.2 mmol). A yield of 48% is obtained. Example 8:

[0235] Chlorodicyclohexylborane (0.1 mmol, 1 eq.), triethylamine (0.11 mmol, 1.1 eq.), and benzene (0.3 mL) are introduced into a New Era NMR tube under an inert atmosphere. The inert atmosphere is removed, and the tube is charged with hydrogen (10 bar). The mixture is stirred for 18 h at room temperature (20 ± 5°C). The excess hydrogen is removed, and the dicyclohexylborane formed is titrated by reaction with 4-octyne (0.2 mmol). A yield of 83% is obtained. Example 9:

[0236] Chlorodicyclohexylborane (0.1 mmol, 1 eq.), dicyclohexylmethylamine (0.11 mmol, 1.1 eq.), and dichloromethane (0.3 mL) are introduced into a New Era NMR tube under an inert atmosphere. The inert atmosphere is removed, and the tube is charged with hydrogen (10 bar). The mixture is stirred for 18 h. The excess hydrogen is removed, and the dicyclohexylborane formed is titrated by reaction with 4-octyne (0.2 mmol). A yield of 57% is obtained. Example 10:

[0237] Chlorodicyclohexylborane (0.1 mmol, 1 eq.), tert-butylimino-tri(pyrrolidino)phosphorane (0.11 mmol, 1.1 eq.), and dichloromethane (0.3 mL) are introduced into a New Era NMR tube under an inert atmosphere. The inert atmosphere is removed, and the tube is charged with hydrogen (10 bar). The mixture is shaken. for 18 hours at room temperature (20 ± 5°C). Excess hydrogen is removed and the dicyclohexylborane formed is titrated by reaction with 4-octyne (0.2 mmol). A yield of 41% is obtained. Example 11:

[0238] 9-Borabicyclo[3.3.1]nonyl trifluoromethanesulfonate in hexane solution (0.5 M, 200 pL, 0.1 mmol, 1 eq.), triethylamine (0.11 mmol, 1.1 eq.), and benzene (0.3 mL) are introduced into a New Era NMR tube under an inert atmosphere. The inert atmosphere is removed, and the tube is charged with hydrogen (10 bar). The mixture is stirred for 46 h at room temperature (20 ± 5°C). The excess hydrogen is removed, and the dicyclohexylborane formed is titrated by reaction with 4-octyne (0.2 mmol). A yield of 67% is obtained. Example 12:

[0239] A solution of the adduct 9-chloro-9-borabicyclo[3.3.1]nonane-diethyl ether (1 mmol, 1 eq.), triethylamine (1.1 mmol, 1.1 eq.) in anisole (2 mL) is introduced under a hydrogen atmosphere into a conditioned autoclave. The autoclave is pressurized under hydrogen (15 bar). The mixture is stirred for 24 h at room temperature (20 ± 5°C). The reactor is degassed and the reaction mixture is recovered under an inert atmosphere. The by-products are precipitated by the addition of THF and the suspension is filtered through Celite. The solvents are removed under reduced pressure. An isolated yield of 84% of the 9-borabicyclo[3.3.1]nonane dimer is obtained.

[0240] The results are shown in the following table:

[0241] [Tables 1] Input (pseude-) haioboraùe Base (eq.) Catalyst (%mol) itself value temperature fc) time yield (W 1 ratBCl NfEts Uêq) te rat. (W%) £«A TA 6) if 2 ratP.fi MEt, (2 eq) beat. (2%) T.À. 4) 24 3 catBCl œt3 (2eq) Ru rat. (5%) C^DS: 88 6] 21 4 ratBCt NEtj [2eq] CyzB€i (18%) T.À. 11) 68 5 catBC1 NEt3 (1 eqj Cy2B€l (16%) TA 22h 17 6 ​​catBC1 NEt3 (1.5 eq) CyzBCl (18%) CA TA 19h 24 7' rat&cl NEt3 p.leq) BPh= (10%) C6ds 60 4) 5 8 PhBC12 NEt3 (2eq) CyjBCl (10%) £A TA 5) >09(PhBHCl] g PhBCIj NEtj (2eq) 9-BB1M (18%) ÇA TA y 92 (PhBHCI) W PhBClj NEts P^q) 9-B8?M (10%) CA 80 Sj 45 (PhBH2), 54 (PhBHCI) 11 1-9-BBN NEt3 (1.2 eq) (-)-DIP chioride (10%) ca 60 5j 9 12 1-9-BBN Cy2MMe (12 eq) tr rat. (18%) CA 80 4d 48 13 BCi3 NEt, (2.1eq) BPhj(10%) ¢5¾ 120 5d 56 (HSCÜ 14 BClj NEE (2.1eq) KEtjBH (10%) CA 120 3:43 p.m. (HBey 15 BEL NEtj (ZéqJ 9-BBM (10%) CA 1'20 62 (HBClj) 15 Cy2BCl NEtj (1.1 eq) - cd2ci2 TA iSh 75 17 CyzBCI DiPEA (1.1 êq) CDj€i2 TA 18 b 51 18 Cy2B€l BTPP (1.1 eq) - 0¾¾ TAISh 41 19 CftBCi €yzNMe (1.1 eq) - CEfjCIj TA 18 b 57 . All reactions are carried out at the pressure of the bar, except where noted. TA? : ambient temperature (20 ± S'C). 3: yielded by *H RMM b: reaction carried out at 5 bar 1: Reaction carried out at 15 bar $: isolated yield The operating conditions were not optimized for all the tests included in the table, but without excessive effort, it will be easy for a person skilled in the art to optimize the conditions and achieve yields >50% compared to the initial boron reagent.

[0242] (Pseudo-)Catalyst Input h < ac^ôStf S'&CJb S < v ■ solvent temperature time yield 2® NEt, ^C3 (Lli CSD« TA 18h 83 21 ■ QD-jCl TA 18h 80 22 c- - Tôiuene- d3 TA 18h 53 23 Cy.Sd . [1.1 eq) THF-dS T JL' 18h 27 Cyciphexa 24 Cÿ2Bd *? . O^BCt .,^3 , î: (1.1 eq) CSDS se 6h 15 29 C¥2&Ü (1.1 eq) Çsbs 70 8h 7 3® Cy^Ci ,?®3 ri (1.1 eq) CgDg; 128 6h 4 31 , N Et , Cy^BCP „, (1.1 eq) T.À. 6h 57 32 T2 (1.1 eq) TA 6h 79 33 Ci-9- NEt3 BBM.Et.O (1.1 eq) £4¾ TA 2Gh 85 34 Ci-9- NEt3 BBM.EtjO1 (1.1 eq) anisoie TA, 48h 84* bss (btcycloï2. 35 2.1] N Et, -2heptyi) (1.1 eq) CSDS TA 46h 32 Chioroborane 3® C'™'1 Æ CA TA 4Sh §7 37 N And,!Si S 38 . Cv7NMe (1.1 eq) £«Rb TA 7j 17 39 r DiPEA(ll Cy2B€i CsQs TA ïj 34 All reactions are carried out at a pressure of 18 bar, unless otherwise notated. TA*: ambient temperature (23 ± 5°C). . ":yield determined by NMR : reaction carried out at S bar : reaction carried out at 15 bar isolated yield The operating conditions were not optimized for all the trials included in the table, but without excessive effort, it will be easy for a person skilled in the art to optimize the conditions and achieve yields >58% compared to the initial boron reagent.

[0243] Some abbreviations used in the context of the present invention are indicated below:

[0244] BTPP: tert-butylimino-tri(pyrrolidino)phosphorane

[0245]

[0246]

[0247]

[0248]

[0249] CatBCl: chlorocatecolborane BBN: borabicyclo[3.3.1]nonane DIP: diisopinocampheylborane DIPEA: A,A-düsopropylethylamine TBD: 1,5,7-triazabicyclo[4.4.0]dec-5-ene

Claims

Claims

1. A process for preparing a hydroborane of formula (I) (RJ^R^BHh from a (pseudo-)haloborane of formula (II) (R1)o(R2)mBXn in which - R1 and R2, which may be identical or different, are an alkyl group containing 1 to 12 carbon atoms, a cycloalkyl group containing 3 to 12 carbon atoms, an aryl group containing 6 to 20 carbon atoms, an alkoxy group in which the alkyl group contains 1 to 12 carbon atoms, a cycloalkoxy (-O-cycloalkyl) group in which the cycloalkyl group contains 3 to 12 carbon atoms, an aryloxy group in which the aryl group contains 6 to 20 carbon atoms, a -NR3R4 group, with R3 and R4, which may be identical or different, representing a hydrogen atom, an alkyl group containing 1 to 12 carbon atoms, a cycloalkyl group containing 3 to 12 carbon atoms, an aryl group containing 6 to 20 carbon atoms, said alkyl and cycloalkyl groups being optionally substituted; or - R1 and R2 taken together with the boron atom to which they are bonded, form a heterocycle comprising from 5 to 12 members, said heterocycle group being optionally substituted; - n is 1, 2, 3; - m is 0, 1; - o is 0, 1; - X represents Cl, Br, I, -OSO2R with R being a -CF3, -CH3 or o-tolyl, m-tolyl, p-tolyl group; characterized in that the (pseudo-)haloborane of formula (II) is brought into contact with (A) a catalyst selected from • a metal complex in which the metal is a transition metal chosen from chromium, tungsten, manganese, rhenium, silver, rhodium, cobalt, iron, nickel, copper, iridium, ruthenium, osmium, molybdenum, gold, platinum and palladium, and the ligands linked to the transition metals are chosen from: - nitrogenous bases such as tertiary amines selected from 4-dimethylaminopyridine (DMAP), 1,4-diazabicyclo[2.2.2]octane (DABCO), A-diisopropylethylamine (DIPEA or DIEA), bipyridyl (bipy), terpyridine (terpy); phenanthroline (phen), ethylenediamine, AAA',A'-tetra-methyl-ethylenediamine (TMEDA), quinoline and pyridine; - phosphorus bases such as alkyl and aryl phosphines chosen from triphenylphosphine, 2,2'-bis(diphenylphosphino)-1,r-binaphthyl (BINAP), triisopropylphosphine, tris[2-diphenylphosphino)ethyl]phosphine (PP3), 4,5-bis-(di-i-propylphosphinomethyl) acridine, 4,5-bis-(di-phenylphosphinomethyl) acridine, tricyclohexylphosphine, 1,2-bis-diphenylphosphinoethane (dppe), 1,2-bis(diphenylphosphino)ethane (dppb); 'POCOP = (C6H4){ 1,3-OPR2}2) where R is an aryl group having 6 to 20 carbon atoms such as phenyl or an alkyl group having 1 to 12 carbon atoms such as tert-butyl and isopropyl, in particular, l,3-bis[(di-tert-butylphosphino)oxy]benzene ((tBu)2P-O-C6H4-OP(tBu) 2);R'PNP = R'2PCH2CH2N(H)CH2CH2PR'2 where R' is an aryl group having 6 to 20 carbon atoms such as phenyl or an alkyl group having 1 to 12 carbon atoms such as tert-butyl and isopropyl, in particular, bis[2-diphenylphosphino)ethyl]amine {((C6H5)2P-CH2-CH2)2NH} and bis[2-di-isopropylphosphino)ethyl]amine {((CH3)2CH)2P-CH2-CH2)2 NH}; - oxygenated bases such as acetate (CH3COO ), acetylacetonate ([CH3COCHCOCH3] ), methanolate (CH3-O ), ethanolate (CH3-CH2 -O-); - carbon ligands chosen from CO, CN; - halogens chosen from Cl, Br, I; - a hydrogen atom; - N-heterocyclic carbenes derived from an imidazolium salt chosen from the salts of 1,3-bis(2,6-diisopropylphenyl)-1H-imidazol-3-ium, 1,3-bis(2,6-diisopropylphenyl)-4,5-dihydro-1H-imidazol-3-ium, 1,3-bis(2,4,6-trimethylphenyl)-lH-imidazol-3-ium, 1,3-bis(2,4,6-trimethylphenyl)-4,5-dihydro-lH-imidazol-3-ium, 4,5-dichloro-l,3-bis(2,6-diisopropylphenyl)-lH-imidazol-3-ium, l,3-di-tert-butyl-lH-imidazol-3-ium, l,3-di-tert-butyl-4,5-dihydro-lH-imidazol-3-ium, or a mixture of these ligands, the metal complex optionally comprising a counter anion chosen from PF6, BF4, CF3SO3 or OTf, • a boron compound comprising at least 3 substituents chosen from a hydrogen atom, an alkyl group comprising 1 to 12 carbon atoms, a cycloalkyl group comprising 3 to 12 carbon atoms, an aryl group comprising 6 to 20 carbon atoms, a halogen chosen from Cl, Br, I, or a mixture of these substituents, said alkyl, cycloalkyl and aryl groups being optionally substituted, the complex composed of boron optionally comprising a counter cation chosen from Li+, Na+, K+ or Mg2+, • a heterocyclic boron compound such as 9-borabicyclo[3.3.1]nonane or 9-BBN or one of its substituted derivatives such as 9-chloro-borabicyclo[3.3.1]nonane or Cl-9-BBN, 9-iodo-borabicyclo[3.3.1]nonane or I-9-BBN, 9-triflate-borabicyclo[3.3.1]nonane or TfO-9-BBN,, • a (pseudo-)haloborane of formula (II) as defined above; and (B) a nitrogenous or phosphorous base having a pKa of between 5 and 50 in DMSO or in acetonitrile chosen from . a tertiary amine comprising an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 3 to 12 carbon atoms, an aryl group having 6 to 20 carbon atoms, in particular triethylamine (NEt3), N,N-diisopropylethylamine (DIPEA) and N,N-dicyclohexylmethylamine (Cy2NMe), . a phosphazene in particular tert-butylimino-tri(pyrrolidino) phosphorane or BTPP, . a proazaphosphatrane type base, in particular 2,8,9-triisopropyl-2,5,8,9-tetraaza-l-phosphabicyclo[3.3.3]undecane, 2,8,9-triisobutyl-2,5,8,9-tetraaza-l-phosphabicyclo[3.3.3]undecane, 2,8,9-trimethyl-2,5,8,9-tetraaza-l-phosphabicyclo[3.3.3]undecane; And (C) in a solvent or a mixture of at least two solvents chosen from: • ethers chosen from diethyl ether, THF, dioxane, anisole, and diglyme, • tertiary amines chosen from triethylamine (NEt3), N,N-diisopropylethylamine (DIPEA) and N,N-dicyclohexylmethylamine (Cy2NMe), • hydrocarbons and aromatics chosen from benzene, toluene, xylene, pentane, hexane, cyclohexane, • pyridine-based solvents chosen from lutidine, or 2,6-di-tert-butylpyridine, • alkyl halides chosen from chloroform and methylene chloride, • aryl halides chosen from chlorobenzene and dichlorobenzene; under hydrogen pressure between 0.1 bar and 300 bar.

2. Method according to claim 1, characterized in that R 1 and R 2, identical or different, represent an alkyl group comprising 1 to 12 carbon atoms, a cycloalkyl group comprising 3 to 12 carbon atoms, an aryl group comprising from 6 to 20 carbon atoms, said alkyl, cycloalkyl and aryl groups being optionally substituted.

3. Process according to one of claims 1 or 2, characterized in that R 1 and R 2, identical or different, are cyclohexyl, bicyclo[2,1,1] hexyl, bicyclo[2,2,1] heptyl, bicyclo[3.3.1]nonane, isopinocampheyl, phenyl, benzyl, naphthyl, o-tolyl, m-tolyl, p-tolyl.

4. A method according to claim 1, characterized in that R 1 and R 2 taken together with the boron atom to which they are bonded, form a heterocycle comprising from 5 to 10 members, said heterocycle group being optionally substituted.

5. Process according to one of claims 1 or 4, characterized in that Ri and R2 taken together with the boron atom to which they are bonded, form a catecholboranyl or CatB-, 9-borabicyclo[3.3.1] nonanyl or 9-BBN, pinacolboranyl or -Bpin.

6. Process according to any one of claims 1 to 5, characterized in that the catalyst (A) is chosen from a metal complex whose metal is iridium or ruthenium, and the ligands bound to the transition metals are chosen from: - phosphorus bases such as / BuPOCOP = (C6H3){ l,3-OPtBu2}2); 4,5-bis-(di-i-propylphosphinomethyl)acridine, - carbon ligands such as CO, - halogens chosen from Cl, Br, I, - a hydrogen atom, or a mixture of these ligands.

7. Process according to any one of claims 1 to 6, characterized in that the catalyst (A) is ruthenium chlorocarbo-nylhydrido[4,5-bis-(di-iso-propyl phosphinomethyl)acridine], [Ir( / BuPOCOP)HCl].

8. Process according to any one of claims 1 to 7, characterized in that the catalyst (A) is 9-borabicyclo[3.3.1]nonane or 9-BBN or one of its substituted derivatives such as 9-chloro-borabicyclo[3.3.1]nonane or C1-9-BBN, 9-triflate-borabicyclo[3.3.1]nonane or TfO-9-BBN.

9. Process according to any one of claims 1 to 7, characterized in that the catalyst (A) is a boron compound comprising 3 substituents chosen from - a hydrogen atom, - an alkyl group comprising 1 to 12 carbon atoms, in particular ethyl, propyl, isopropyl, butyl and isobutyl, - a cycloalkyl group comprising 5 to 10 carbon atoms, in particular cyclohexyl, bicyclo[2,1,1]hexyl, bicyclo[2,2,1]heptyl, bicyclo[3,3,1]nonane, isopinocampheyl, - an aryl group comprising from 6 to 20 carbon atoms, in particular phenyl (Ph) and pentafluorophenyl (-C6F5), - a halogen chosen from Cl, Br, I, or a mixture of these substituents.

10. Process according to claim 9, characterized in that the catalyst (A) is chlorodicyclohexylborane or Cy2BCl, bis(bicyclo[2,2,l]-2-heptyl)chloroborane, chloro-diisopinocampheylborane or Cl-DIP, triphenylborane or BPh3.

11. Process according to claim 9, characterized in that the catalyst (A) is dicyclohexylborane or Cy2BH.

12. Process according to claim 9, characterized in that the catalyst (A) is triphenylborane or BPh3.

13. Process according to any one of claims 1 to 5, characterized in that the catalyst (A) is a boron compound comprising 4 substituents, one being a hydrogen atom while the other 3 substituents are chosen from - a hydrogen atom, - an alkyl group comprising 1 to 12 carbon atoms, in particular ethyl, propyl, isopropyl, butyl and isobutyl, - a cycloalkyl group comprising 5 to 10 carbon atoms, in particular cyclohexyl, bicyclo[2,1,1]hexyl, bicyclo[2,2,1]heptyl, bicyclo[3,3,1]nonane, isopinocampheyl, - an aryl group comprising 6 to 20 carbon atoms, in particular phenyl (-Ph) and pentafluorophenyl (-C6F5), - a halogen chosen from Cl, Br, I, or a mixture of these substituents, the boron compound comprising a counter cation chosen from Li+, Na+, K+

14. rv . Process according to claim 13, characterized in that the catalyst (A) is potassium triethylborohydride or KEt3BH.

15. Process according to any one of claims 1 to 5, characterized in that the catalyst (A) is a (pseudo-)haloborane of formula (II) in which - R 1 and R 2 , identical or different, represent a cycloalkyl group comprising 5 to 10 carbon atoms, in particular cyclohexyl, bicyclo[2,1,1] hexyl, bicyclo[2,2,1] heptyl, bicyclo[3,3,1]nonane, isopinocampheyl, said cycloalkyl group being optionally substituted; - n is 1, 2, 3; - m is 0, 1; - o is 0, 1; - X represents Cl, Br, I, -OSO2R with R being a group -CF3, -CH3 or o-tolyl, m-tolyl, p-tolyl.

16. Process according to claim 15, characterized in that the catalyst (A) is chlorodicyclohexylborane or Cy2BCl, dicyclohexylborane triflate, chlorodiisopinocampheylborane or Cl-DIP, bis(bicyclo[2,2,1]-2-heptyl)chloroborane.

17. Process according to any one of claims 1 to 5, characterized in that the catalyst (A) is a (pseudo-)haloborane of formula (II) in which - R1 and R2 taken together with the boron atom to which they are bonded, form a heterocycle comprising from 5 to 10 members, in particular, 9-borabicyclo[3.3.1]nonanyl or 9-BBN, said heterocycle group being optionally substituted; - n is 1, 2, 3; - m is 0, 1; - o is 0, 1; - X represents Cl, Br, I, -OSO2R with R being a group -CF3, -CH3 or o-tolyl, m-tolyl, p-tolyl.

18. A process according to claim 17, characterized in that the catalyst (A) is 9-chloro-borabicyclo[3.3.1]nonane or C1-9-BBN, 9-triflate-borabicyclo[3.3.1]nonane or TfO-9-BBN.

19. Process according to any one of claims 1 to 18, characterized in that the quantity of catalyst used in the process of the invention is from 0.1 to 100 mol%, relative to the (pseudo-)haloborane of formula (II).

20. Process according to any one of claims 1 to 19, characterized in that the base (B) is a tertiary amine comprising an alkyl group comprising 1 to 8 carbon atoms, a cycloalkyl group comprising 5 to 10 carbon atoms, an aryl group comprising 6 to 10 carbon atoms, in particular triethylamine (NEt3), N,N-diisopropylethylamine (DIPEA) and N,N-dicyclohexylmethylamine (Cy2NMe).

21. Process according to any one of claims 1 to 20, characterized in that the amount of base used is 1 to 30 equivalents, relative to the number of BX bonds to be hydrogenolyzed.

22. Process according to any one of claims 1 to 21, characterized in that the preparation of a hydroborane of formula (I) from a (pseudo-) haloborane of formula (II) takes place in a solvent or a mixture of at least two solvent(s) (C), chosen from: • ethers chosen from diethyl ether, THF, dioxane, anisole, and diglyme, • amines chosen from triethylamine (NEt3), N,N-diisopropylethylamine (DIPEA) and N,N-dicyclohexylmethylamine (Cy2NMe), • lutidine, • hydrocarbons and aromatics chosen from benzene, toluene, xylene, pentane, hexane, cyclohexane, • alkyl halides chosen from chloroform and methylene chloride, • aryl halides chosen from chlorobenzene and dichlorobenzene.

23. Process according to any one of claims 1 to 22, characterized such that in solution, the concentration of (pseudo-)haloborane of formula (II) is between 0.0 μM and 10 μM.

24. Process according to any one of claims 1 to 23, characterized in that the preparation of a hydroborane of formula (I) from a (pseudo-)haloborane of formula (II) takes place at a hydrogen pressure of between 1 bar and 50 bar.

25. Use of the process of the invention according to any one of claims 1 to 24, - in organic synthesis for the reduction of carbonyl function or for the preparation of boronic ester by borylation reaction, - in inorganic synthesis in the production of industrial molecules such as methanol, formic acid, ammonia, - for the depolymerization of lignin, and - for the depolymerization of oxygenated polymers such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT), poly-trimethylene terephthalate (PTT), polyethylene naphthalate (PEN), polylactic acid (PLA), polyglycolic acid (PGA), polyca-prolactone (PCL), polycarbonate (PC-BPA).

26. Use of a process according to any one of claims 1 to 24, for the recycling of (pseudo-)haloboranes derived from the corresponding hydroboranes.