JP4754182B2 - Method for producing phosphine-borane complex - Google Patents

Description

  The present invention relates to a method for producing a phosphine-borane complex.

また、非特許文献２には、パラジウム触媒下、アリールトリフレートと反応させてトリアリールホスフィンが合成できることが報告されている。

A phosphine-borane complex is a compound that is generally not decomposed into air or water, but is easily deboraneated by an amine and converted to phosphine, and is therefore used as a phosphine equivalent in the synthesis of many organophosphorus compounds. For example, Non-Patent Document 1 describes the following reaction formula as a synthesis method of 1,2-bis [(o-anisyl) phenylphosphino] ethane (DIPAMP) useful as a ligand for asymmetric reduction reaction. Yes.

Non-Patent Document 2 reports that triarylphosphine can be synthesized by reacting with aryl triflate under a palladium catalyst.

And as a manufacturing method of a phosphine-borane complex,
1) A method of obtaining a phosphine-borane complex by reacting phosphine oxide in the presence of cerium chloride, sodium borohydride and lithium aluminum hydride (Non-patent Document 3),
2) A method of obtaining a phosphine-borane complex by reacting phosphine oxide in the presence of methyl triflate, lithium aluminum hydride and borane-tetrahydrofuran complex (Non-patent Document 4),
3) A method of obtaining a phosphine-borane complex by reacting borane-tetrahydrofuran complex using phosphine as a raw material (Non-patent Document 5),
4) A method of reacting lithium aluminum hydride and borane-tetrahydrofuran complex using chlorophosphine as a raw material to obtain a phosphine-borane complex (Non-patent Document 6),
5) A method of obtaining a phosphine-borane complex by reacting phosphine oxide in the presence of diethylborane (Non-patent Document 7) and 6) A reaction of cyclic phosphine oxide in the presence of borane-dimethylsulfide complex to obtain a phosphine-borane complex. A synthesis method (Non-patent Document 8) for obtaining the above has been reported.
Heteroatom Chemistry, 3, 563-575, 1992 Tetrahedron Letters, 40, 201-204, 1999 Journal of the American Chemical Society, 107, 5301-5303, 1985 Organic Letters, No. 3, pp. 87-90, 2001 Angelwandte Chemie International Edition, 18, 781-782, 1979 Journal of the American Chemical Society, 112, 5244-5252, 1990 Chemische Berichte, 120, 1117-1123, 1987 Journal of the Chemical Society, Perkin Transactions 1, 4451-4455, 2000

  In 3) and 4), trivalent organophosphorus compounds that are easily oxidized and unstable are used as reaction reagents, and lithium aluminum hydride is used as the reducing agent in 1), 2), and 4). Operation is complicated and safety is questioned. In addition, it is difficult to selectively obtain only a phosphine-borane complex by the synthesis method of 5), and in 6), only a synthesis example of a cyclic phosphine-borane complex has been reported.

〔式中、R¹、R²およびR³は同一または異なって水素原子、ハロゲン原子、置換されていてもよいアルキル基、置換されていてもよいシクロアルキル基、置換されていてもよいアリール基または置換されていてもよい複素環基を示す（R¹およびR²は、隣接するリン原子とともに4ないし6員環を形成してもよい）〕で表される化合物〔以下、化合物(II)と略記することもある〕またはその塩を、ボラン試薬の存在下に溶媒中で初めて反応させたところ式

〔式中、各記号は前記と同意義を表す〕で表されるホスフィン-ボラン錯体〔以下、化合物(I)と略記することもある〕またはその塩が温和な条件で、かつ高収率で得られることを見出し、これらに基づいて本発明を完成するに至った。 The present inventors have studied various methods for producing phosphine-borane complexes used for the synthesis of organophosphorus compounds,

[Wherein, R ¹ , R ² and R ³ are the same or different and each represents a hydrogen atom, a halogen atom, an optionally substituted alkyl group, an optionally substituted cycloalkyl group, or an optionally substituted aryl group. Or a heterocyclic group which may be substituted (R ¹ and R ² may form a 4- to 6-membered ring with the adjacent phosphorus atom)] [hereinafter referred to as compound (II) Or a salt thereof for the first time in a solvent in the presence of a borane reagent.

[Wherein each symbol is as defined above] or a phosphine-borane complex (hereinafter sometimes abbreviated as compound (I)) or a salt thereof under mild conditions and in a high yield. Based on these findings, the present invention has been completed.

〔式中、R¹、R²およびR³は同一または異なって水素原子、ハロゲン原子、置換されていてもよいアルキル基、置換されていてもよいシクロアルキル基、置換されていてもよいアリール基または置換されていてもよい複素環基を示す（R¹およびR²は、隣接するリン原子とともに4ないし6員環を形成してもよい）〕で表される化合物またはその塩を、ボラン試薬の存在下に溶媒中で変換させることを特徴とする式

〔式中、各記号は前記と同意義を示す〕で表されるホスフィン-ボラン錯体またはその塩の製造法、
〔２〕R³が水素原子である前記〔１〕記載の製造法、
〔３〕R¹とR²が、隣接するリン原子とともに５員環を形成している前記〔２〕記載の製造法、
〔４〕R¹およびR²が同一または異なって水素原子、ハロゲン原子、置換されていてもよいアルキル基、置換されていてもよいシクロアルキル基、置換されていてもよいアリール基または置換されていてもよい複素環基（R¹およびR²は、隣接するリン原子とともに4ないし6員環を形成してもよい）、Ｒ³がハロゲン原子、置換されていてもよいアルキル基、置換されていてもよいシクロアルキル基、置換されていてもよいアリール基または置換されていてもよい複素環基である前記〔１〕記載の製造法、
〔５〕R¹とR²が、隣接するリン原子とともに４又は６員環を形成している前記〔４〕記載の製造法、
〔６〕R¹およびR²が同一または異なって置換されていてもよいアリール基である前記〔２〕又は〔４〕記載の製造法、
〔７〕R¹およびR²が同一または異なって1ないし5個の低級アルキル基、低級アルコキシ基、ハロゲン原子、モノ低級アルキルアミノ基またはジ低級アルキルアミノ基で置換されていてもよいフェニルである前記〔６〕記載の製造法、
〔８〕R¹およびR²が同一または異なって低級アルキル基または低級シクロアルキル基である前記〔２〕又は〔４〕記載の製造法、
〔９〕ボラン試薬がボラン-テトラヒドロフラン錯体である前記〔１〕記載の製造法等に関する。 That is, the present invention provides [1] formula

[Wherein, R ¹ , R ² and R ³ are the same or different and each represents a hydrogen atom, a halogen atom, an optionally substituted alkyl group, an optionally substituted cycloalkyl group, or an optionally substituted aryl group. Or a heterocyclic group which may be substituted (R ¹ and R ² may form a 4- to 6-membered ring together with an adjacent phosphorus atom)] or a salt thereof, borane reagent Wherein the transformation is carried out in a solvent in the presence of

[Wherein each symbol is as defined above] a process for producing a phosphine-borane complex or a salt thereof,
[2] The process according to [1], wherein R ³ is a hydrogen atom.
[3] The production method of the above-mentioned [2], wherein R ¹ and R ² form a 5-membered ring with an adjacent phosphorus atom,
[4] R ¹ and R ² are the same or different and are a hydrogen atom, a halogen atom, an optionally substituted alkyl group, an optionally substituted cycloalkyl group, an optionally substituted aryl group or a substituted An optionally substituted heterocyclic group (R ¹ and R ² may form a 4- to 6-membered ring with the adjacent phosphorus atom), R ³ is a halogen atom, an optionally substituted alkyl group, a substituted The production method of the above-mentioned [1], which is an optionally substituted cycloalkyl group, an optionally substituted aryl group or an optionally substituted heterocyclic group,
[5] The production method of the above-mentioned [4], wherein R ¹ and R ² form a 4- or 6-membered ring with an adjacent phosphorus atom,
[6] The production method of the above-mentioned [2] or [4], wherein R ¹ and R ² are the same or different and optionally substituted aryl groups,
[7] R ¹ and R ² are the same or different and are phenyl optionally substituted by 1 to 5 lower alkyl groups, lower alkoxy groups, halogen atoms, mono-lower alkylamino groups or di-lower alkylamino groups The production method according to [6] above,
[8] The production method of the above-mentioned [2] or [4], wherein R ¹ and R ² are the same or different and are a lower alkyl group or a lower cycloalkyl group,
[9] The production method of the above-mentioned [1], wherein the borane reagent is a borane-tetrahydrofuran complex.

  A phosphine ligand (for example, 1,2-bis [(e.g., 1,2-bis [(a) that forms a complex with an asymmetric ligand such as ruthenium, iridium, palladium, nickel, rhodium, etc.) o-anisyl) phenylphosphino] ethane (DIPAMP), 1,2-bis (diphenylphosphino) propane (PROPHOS), 2,3-bis (diphenylphosphino) butane (CHIRAPHOS), 2,4-bis (diphenyl) A phosphine-borane complex that is useful as an intermediate for the production of (phosphino) pentane (BDPP) and the like) can be produced in mild conditions and in a high yield by following the production method of the present invention.

In the above formula, R ¹ , R ² and R ³ are the same or different and each represents a hydrogen atom, a halogen atom, an optionally substituted alkyl group, an optionally substituted cycloalkyl group, or an optionally substituted aryl group. Indicates.
Examples of the “halogen atom” represented by R ¹ , R ² and R ³ include fluorine, chlorine, bromine and iodine.

Examples of the alkyl group of the “optionally substituted alkyl group” represented by R ¹ , R ² and R ³ include lower alkyl groups (methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert -C _1-6 alkyl groups such as butyl, pentyl and hexyl).
Examples of the substituent for the alkyl group include (1) nitro, (2) nitroso, (3) cyano, (4) hydroxy, (5) lower alkoxy groups (for example, methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy , sec- butoxy, tert- butoxy, pentoxy, C _1-6 alkoxy groups such as hexyloxy), (6) formyl, (7) a lower alkylcarbonyl group (e.g., acetyl, propionyl, butyryl, isobutyryl, valeryl, isovaleryl, C _1-6 alkyl-carbonyl groups such as pivaloyl), (8) lower alkoxycarbonyl groups (for example, methoxycarbonyl, ethoxycarbonyl, propoxycarbonyl, isopropoxycarbonyl, butoxycarbonyl, isobutoxycarbonyl, sec-butoxycarbonyl, tert- Butoxycarbonyl, pentoxycarbonyl, hexyloxy C _1-6 alkoxy such as carbonyl - carbonyl group), (9) carboxy, (10) N-mono-lower alkylcarbamoyl group (e.g., N- methylcarbamoyl, N- ethylcarbamoyl, N- propylcarbamoyl, N- isopropylcarbamoyl N-mono C _1-6 alkyl-carbamoyl groups such as N-butylcarbamoyl, N-isobutylcarbamoyl, N-tert-butylcarbamoyl), (11) N, N-di-lower alkylcarbamoyl groups (for example, N, N -N, N-diC _1-6 alkyl-carbamoyl groups such as -dimethylcarbamoyl, N, N-diethylcarbamoyl, N, N-dipropylcarbamoyl, N, N-diisopropylcarbamoyl, N-ethyl-N-methylcarbamoyl) , (12) halogen atoms (fluorine, chlorine, bromine, iodine), (13) mono-lower alkylamino groups (eg methylamino, ethylamino, propylamino, isopropylamino) , Mono-C _1-6 alkylamino groups such as butylamino, isobutylamino, sec-butylamino, tert-butylamino, pentylamino, hexylamino), (14) di-lower alkylamino groups (for example, dimethylamino, And di-C _1-6 alkylamino groups such as diethylamino, dipropylamino, diisopropylamino, dibutylamino, N-ethyl-N-methylamino) and the like. One to three selected from these substituents may be present at substitutable positions.

Examples of the cycloalkyl group of the “optionally substituted cycloalkyl group” represented by R ¹ , R ² and R ³ include a lower cycloalkyl group (C _3-6 cyclohexane such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl and the like). Alkyl group) and the like.
Examples of the substituent of the “cycloalkyl group” include the same number and the same number of substituents as the substituent which the “optionally substituted alkyl group” may have.

The aryl group of the “optionally substituted aryl group” represented by R ¹ , R ² and R ³ is, for example, a C _6-10 aryl group such as phenyl, 1-naphthyl, 2-naphthyl, biphenyl, naphthyl- A ring assembly aromatic hydrocarbon group such as phenyl is shown.
Substituents for the “aryl group” include (1) nitro, (2) nitroso, (3) cyano, (4) hydroxy, (5) lower alkyl groups (eg, methyl, ethyl, propyl, isopropyl, butyl, C _1-6 alkyl groups such as isobutyl, sec-butyl, tert-butyl, pentyl, hexyl), (6) lower alkoxy groups (eg, methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy, sec-butoxy, tert -C _1-6 alkoxy groups such as butoxy, pentoxy, hexyloxy), (7) formyl, (8) lower alkylcarbonyl groups (for example, C _1- such as acetyl, propionyl, butyryl, isobutyryl, valeryl, isovaleryl, pivaloyl, etc.) ₆ alkyl-carbonyl group), (9) lower alkoxycarbonyl group (for example, methoxycarbonyl, ethoxycarbonyl, propoxycarbonyl, i C _1-6 alkoxy-carbonyl groups such as sopropoxycarbonyl, butoxycarbonyl, isobutoxycarbonyl, sec-butoxycarbonyl, tert-butoxycarbonyl, pentoxycarbonyl, hexyloxycarbonyl), (10) carboxyl, (11) N- Mono-lower alkylcarbamoyl groups (for example, N-monoC carbamoyl, N-ethylcarbamoyl, N-propylcarbamoyl, N-isopropylcarbamoyl, N-butylcarbamoyl, N-isobutylcarbamoyl, N-tert-butylcarbamoyl, etc. _1-6 alkyl-carbamoyl group), (12) N, N-di-lower alkylcarbamoyl group (for example, N, N-dimethylcarbamoyl, N, N-diethylcarbamoyl, N, N-dipropylcarbamoyl, N, N- N, N-diC _1-6 alkyl-carbamoyl such as diisopropylcarbamoyl, N-ethyl-N-methylcarbamoyl Group), (13) halogen atoms (fluorine, chlorine, bromine, iodine), (14) mono-lower alkylamino groups (eg, methylamino, ethylamino, propylamino, isopropylamino, butylamino, isobutylamino, sec- Mono-C _1-6 alkylamino groups such as butylamino, tert-butylamino, pentylamino, hexylamino), (15) di-lower alkylamino groups (for example, dimethylamino, diethylamino, dipropylamino, diisopropylamino, Di-C _1-6 alkylamino groups such as dibutylamino and N-ethyl-N-methylamino), (16) halogeno-lower alkyl groups (eg, fluoromethyl, difluoromethyl, trifluoromethyl, 2,2,2 -Halogeno-C _1-6 alkyl groups such as trifluoroethyl, chloromethyl, dichloromethyl, trichloromethyl) and the like. It may have 1 to 5 selected from these substituents at substitutable positions.

The heterocyclic group of the “optionally substituted heterocyclic group” represented by R ¹ , R ² and R ³ is, for example, 1-pyrrolyl, 2-pyrrolyl, 3-pyrrolyl, 1-imidazolyl, 2-imidazolyl. , 4-imidazolyl, 5-imidazolyl, 1-pyrrolidinyl, 2-pyrrolidinyl, 3-pyrrolidinyl, pyrrolinyl, 1-imidazolidinyl, 2-imidazolidinyl, 3-imidazolinyl, 4-imidazolidinyl, imidazolinyl, 2-pyridyl, 3-pyridyl, 4 -Pyridyl, pyrazinyl, 2-pyrimidinyl, 4-pyrimidinyl, 5-pyrimidinyl, 1-piperidyl, 2-piperidyl, 3-piperidyl, 4-piperidyl, 2-oxazolyl, 4-oxazolyl, 5-oxazolyl, 2-furyl, 3 -Furyl, 2-pyranyl, 3-pyranyl, 4-pyranyl, 5-pyranyl, 6-pyranyl, 1,3-dioxolan-2-yl, 1,3-dioxolan-4-yl, 1,4-dioxane-2 -Ill, 1,4-diochi San-3-yl and the like.
Examples of the substituent of the “heterocyclic group” include the same number and the same number of substituents as the substituent which the “optionally substituted aryl group” may have.

〔式中、環A、環Bおよび環Cは置換基を有していてもよい、R³は前記と同意義を示す〕で表される構造を示すものが挙げられる。上記式中、環が有していてもよい置換基としては、前記の「置換されていてもよいアリール基」の有していてもよい置換基と同個数、同様の置換基が挙げられる。 When R ¹ and R ² together with the adjacent phosphorus atom form a 4 to 6 membered ring, compound (II) can be represented, for example, by the formula

[Wherein, ring A, ring B and ring C may have a substituent, and R ³ has the same meaning as described above]. In the above formula, examples of the substituent that the ring may have include the same number of substituents that are the same as the substituents that the “optionally substituted aryl group” may have.

R ¹ and R ² are preferably an alkyl group that may be the same or different, a cycloalkyl group that may be substituted, or an aryl group that may be substituted.
Of these, a lower alkyl group, a lower cycloalkyl group, or an optionally substituted C _6-10 aryl group is preferable. In particular, phenyl optionally substituted with 1 to 5 lower alkyl groups, lower alkoxy groups, halogen atoms, mono-lower alkylamino groups or di-lower alkylamino groups is preferable. Particularly preferred is phenyl optionally substituted by 1 to 3 lower alkyl groups, lower alkoxy groups, halogen atoms, mono-lower alkylamino groups or di-lower alkylamino groups.
R ³ is preferably a hydrogen atom.

  Examples of the salt of compound (I) and compound (II) include salts with inorganic acids (for example, hydrochloric acid, hydrobromic acid, nitric acid, sulfuric acid, phosphoric acid, etc.) or organic acids (for example, formic acid, acetic acid, triglyceride). And salts with fluoroacetic acid, fumaric acid, succinic acid, tartaric acid, maleic acid, citric acid, succinic acid, malic acid, methanesulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid, etc.). In addition, when the compound (I) and the compound (II) have an acidic group such as a carboxyl group, an inorganic base (for example, an alkali metal or alkaline earth metal such as sodium, potassium, calcium, magnesium, ammonia, etc. Or a salt with an organic base (for example, trimethylamine, triethylamine, pyridine, picoline, ethanolamine, diethanolamine, triethanolamine, dicyclohexylamine, N, N′-dibenzylethylenediamine, etc.).

  Examples of the “borane reagent” used in the present invention include borane-tetrahydrofuran complex, borane-dimethylsulfide complex, borane-amine complex (for example, borane-ammonia complex, borane-tert-butylamine complex, borane-dimethylamine complex, Borane-triethylamine complex, borane-trimethylamine complex, borane-4-ethylmorpholine complex, borane-2,6-lutidine complex, borane-morpholine complex, borane-4-methylmorpholine complex, borane-4-phenylmorpholine complex, borane- And borane complexes such as piperazine complex, borane-pyridine complex, borane-N, N-diethylaniline complex, borane-N, N-diisopropylaniline complex). Of these, borane-tetrahydrofuran complex is preferable.

In the production method of the present invention, compound (II) or a salt thereof is reacted with a borane reagent in a solvent to obtain compound (I) or a salt thereof.
The amount of the borane reagent to be used is about 0.5 to 10 mol, preferably about 3 to 5 mol, per 1 mol of compound (II).
The reaction can be carried out in an inert organic solvent or in an inert water-containing organic solvent. Examples of the organic solvent include hydrocarbons (eg, hexane, pentane, cyclohexane, etc.), aromatic hydrocarbons (eg, toluene, benzene, chlorobenzene, etc.), ethers (eg, diisopropyl ether, diethyl ether, tetrahydrofuran, 1 , 4-dioxane, 1,2-dimethoxyethane, etc.), halogenated hydrocarbons (eg, chloroform, dichloromethane, 1,2-dichloroethane, carbon tetrachloride, etc.), nitriles (eg, acetonitrile, propionitrile, etc.) ) And the like. These solvents may be used alone or as a mixed solvent. Preferred solvents are aromatic hydrocarbons, ethers, halogenated hydrocarbons and the like. More preferred are aromatic hydrocarbons (toluene, benzene).
The reaction temperature in the reaction is about 0 to 40 ° C, preferably about 20 to 30 ° C. The addition time of the borane reagent in the reaction is 0 hour or longer, preferably about 0.5 hour or longer, more preferably about 2 hours or longer. However, it is usually within about 5 hours. The reaction time in the reaction is about 0.5 to 24 hours, preferably about 1 to 5 hours.
The product can also be isolated from the reaction mixture according to a conventional method, and can be easily purified by separation means such as recrystallization, distillation, chromatography and the like.
EXAMPLES The present invention will be described in more detail below with reference to examples and reference examples, but the present invention is not limited to these. In addition, the following apparatus was used for the measurement of each physical property of an Example. ¹ H nuclear magnetic resonance spectrum ( ¹ H-NMR): DPX300 (manufactured by Bruker), internal standard substance: tetramethylsilane. ¹³ C nuclear magnetic resonance spectrum ( ¹³ C-NMR): DPX300 (manufactured by Bruker), internal reference material: CDCl ₃ . ³¹ P nuclear magnetic resonance spectrum ( ³¹ P-NMR): DPX300 (manufactured by Bruker), external reference material: 85% H ₃ PO ₄ aqueous solution.

Reference example 1

窒素気流下、マグネシウム (58.41 g, 3.48 当量)および少量のヨウ素、1,2-ジブロモエタンのテトラヒドロフラン (400 mL)溶液を室温で1時間撹拌した。p-ブロモトルエン(411.11 g, 3.48 当量)のテトラヒドロフラン (2000 mL)溶液を22℃で加えた後、40℃で1時間攪拌した。ついで20℃で亜リン酸ジエチル(94.76 g, 0.69 mol)のテトラヒドロフラン (160 mL)溶液を加えた後、24℃で30分間撹拌した。4℃で6M-HCl (320 mL)を加え、ついで水 (320 mL)、トルエン (1000 mL)を加えた後、室温で30分間攪拌した。反応液を分液し、有機層を水 (320 mL)、5% NaHCO₃水溶液 (320 mL)、5% NaCl水溶液 (320 mL)で順次洗浄し、有機層を減圧ろ過し、ろ液を減圧濃縮した。残渣をn-ヘキサンより再結晶し、乾燥後 (減圧、40℃)、表題化合物(87.12 g, 白色粉末)を得た。収率54.8%
¹H-NMR (300MHz, CDCl₃, TMS) δ: 2.39 (s, 6H), 7.27-7.30 (m, 4H), 7.54 (s, 1H), 7.57 (s, 1H), 7.59 (s, 1H), 7.61 (s, 1H), 8.03 (d, 1H, J_H-P = 477.6 Hz).
¹³C-NMR (75MHz, CDCl₃, CDCl₃) δ: 23.01, 129.16, 130.53, 130.85, 131.02, 131.99, 132.15, 144.38, 144.41.
³¹P-NMR (121MHz, CDCl₃, 85%H₃PO₄) δ: 22.67 (dquint, J_H-P = 477.6 Hz, J_HCC-P = 13.3 Hz). Di (p-tolyl) phosphine oxide

Under a nitrogen stream, a solution of magnesium (58.41 g, 3.48 eq), a small amount of iodine and 1,2-dibromoethane in tetrahydrofuran (400 mL) was stirred at room temperature for 1 hour. A solution of p-bromotoluene (411.11 g, 3.48 eq) in tetrahydrofuran (2000 mL) was added at 22 ° C., and the mixture was stirred at 40 ° C. for 1 hr. Then, a solution of diethyl phosphite (94.76 g, 0.69 mol) in tetrahydrofuran (160 mL) was added at 20 ° C., and the mixture was stirred at 24 ° C. for 30 min. 6M-HCl (320 mL) was added at 4 ° C., water (320 mL) and toluene (1000 mL) were added, and the mixture was stirred at room temperature for 30 min. The reaction solution was separated, and the organic layer was washed successively with water (320 mL), 5% aqueous NaHCO ₃ solution (320 mL), 5% aqueous NaCl solution (320 mL), the organic layer was filtered under reduced pressure, and the filtrate was reduced under reduced pressure. Concentrated. The residue was recrystallized from n-hexane and dried (reduced pressure, 40 ° C.) to obtain the title compound (87.12 g, white powder). Yield 54.8%
¹ H-NMR (300MHz, CDCl ₃ , TMS) δ: 2.39 (s, 6H), 7.27-7.30 (m, 4H), 7.54 (s, 1H), 7.57 (s, 1H), 7.59 (s, 1H) , 7.61 (s, 1H), 8.03 (d, 1H, J _HP = 477.6 Hz).
¹³ C-NMR (75 MHz, CDCl ₃ , CDCl ₃ ) δ: 23.01, 129.16, 130.53, 130.85, 131.02, 131.99, 132.15, 144.38, 144.41.
³¹ P-NMR (121MHz, CDCl ₃ , 85% H ₃ PO ₄ ) δ: 22.67 (dquint, J _HP = 477.6 Hz, J _HCC-P = 13.3 Hz).

Reference example 2

アルゴン雰囲気下、マグネシウム (2.94 g, 2.00 当量)および少量のヨウ素、1,2-ジブロモエタンのテトラヒドロフラン (60 mL)溶液を室温で1時間撹拌した。2-ブロモナフタレン (25.00 g, 2.00 当量)のテトラヒドロフラン (20 mL)溶液を27℃で加えた後、40℃で45分間攪拌した。ついで-9℃で亜リン酸ジエチル(9.77 g, 0.06 mol)の テトラヒドロフラン (10 mL)溶液を加えた後、2℃で3時間撹拌した。-5℃で水 (20 mL)を加え、ついでトルエン (60 mL)、6M-HCl (20 mL)を加えた後分液し、有機層を5% NaHCO₃水溶液、5% NaCl水溶液で順次洗浄し、有機層を無水硫酸マグネシウムで乾燥後、自然ろ過し、ろ液を減圧濃縮した。残渣をイソプロピルエーテル／n-ヘキサンより再結晶し、乾燥後(減圧、40℃)、表題化合物(9.621g,白色粉末)を得た。収率53.0%
¹H-NMR (300MHz, CDCl₃, TMS) δ: 7.49-7.64 (m, 6.5H), 7.86-7.95 (m, 6H), 8.40 (d, 2H, J = 15.7 Hz), 9.15 (0.5H).
¹³C-NMR (75MHz, CDCl₃, CDCl₃)δ: 125.07, 125.23, 127.13, 127.76, 127.93, 128.41, 128.81, 128.96, 132.43, 132.62, 132.82, 132.96, 135.05.
³¹P-NMR (121MHz, CDCl₃, 85%H₃PO₄) δ: 22.99 (dquint, J_H-P = 481.0 Hz, J_HCC-P = 13.4 Hz). Dinaphthylphosphine oxide

Under an argon atmosphere, a solution of magnesium (2.94 g, 2.00 equiv), a small amount of iodine and 1,2-dibromoethane in tetrahydrofuran (60 mL) was stirred at room temperature for 1 hour. A solution of 2-bromonaphthalene (25.00 g, 2.00 equiv) in tetrahydrofuran (20 mL) was added at 27 ° C., and the mixture was stirred at 40 ° C. for 45 min. Then, a solution of diethyl phosphite (9.77 g, 0.06 mol) in tetrahydrofuran (10 mL) was added at −9 ° C., followed by stirring at 2 ° C. for 3 hours. Water (20 mL) was added at -5 ° C, and then toluene (60 mL) and 6M-HCl (20 mL) were added, followed by liquid separation. The organic layer was washed sequentially with 5% NaHCO ₃ aqueous solution and 5% NaCl aqueous solution. The organic layer was dried over anhydrous magnesium sulfate and then naturally filtered, and the filtrate was concentrated under reduced pressure. The residue was recrystallized from isopropyl ether / n-hexane and dried (reduced pressure, 40 ° C.) to obtain the title compound (9.621 g, white powder). Yield 53.0%
¹ H-NMR (300MHz, CDCl ₃ , TMS) δ: 7.49-7.64 (m, 6.5H), 7.86-7.95 (m, 6H), 8.40 (d, 2H, J = 15.7 Hz), 9.15 (0.5H) .
¹³ C-NMR (75 MHz, CDCl ₃ , CDCl ₃ ) δ: 125.07, 125.23, 127.13, 127.76, 127.93, 128.41, 128.81, 128.96, 132.43, 132.62, 132.82, 132.96, 135.05.
³¹ P-NMR (121MHz, CDCl ₃ , 85% H ₃ PO ₄ ) δ: 22.99 (dquint, J _HP = 481.0 Hz, J _HCC-P = 13.4 Hz).

Reference example 3

アルゴン雰囲気下、マグネシウム(7.05 g, 1.93 当量)および少量のヨウ素のテトラヒドロフラン (70 mL)溶液にブロモシクロヘキサン(50.00 g, 2.00 当量)を38〜43℃で加えた後、5℃で1時間攪拌した。ついで5℃で亜リン酸ジエチル(20.70 g, 0.15 mol)を加えた後、5℃で2時間撹拌した。5℃で水 (50 mL)を加え、ついで6M-HCl (50 mL)、トルエン(70 mL)を加え分液した。有機層を水、5% NaHCO₃水溶液、5% NaCl水溶液で順次洗浄し、有機層を無水硫酸マグネシウムで乾燥後、自然ろ過し、ろ液を減圧濃縮した。残渣をヘプタンより再結晶し、乾燥後 (減圧、40℃)、表題化合物 (10.5 g, 白色粉末)を得た。収率37.6%。
¹H-NMR (300MHz, CDCl₃, TMS) δ: 1.25-1.98 (m, 22H), 6.28 (d, 1H, J_H-P = 433.6 Hz).
³¹P-NMR (121 MHz, CDCl₃, 85%H₃PO₄) δ: 50.07 (d, J_H-P = 433.5 Hz). Dicyclohexylphosphine oxide

Bromocyclohexane (50.00 g, 2.00 equiv) was added to a solution of magnesium (7.05 g, 1.93 equiv) and a small amount of iodine in tetrahydrofuran (70 mL) at 38-43 ° C under an argon atmosphere, and the mixture was stirred at 5 ° C for 1 hour. . Next, diethyl phosphite (20.70 g, 0.15 mol) was added at 5 ° C., and the mixture was stirred at 5 ° C. for 2 hr. Water (50 mL) was added at 5 ° C., then 6M-HCl (50 mL) and toluene (70 mL) were added to separate the layers. The organic layer was washed successively with water, 5% aqueous NaHCO ₃ solution, and 5% aqueous NaCl solution, the organic layer was dried over anhydrous magnesium sulfate, naturally filtered, and the filtrate was concentrated under reduced pressure. The residue was recrystallized from heptane and dried (reduced pressure, 40 ° C.) to obtain the title compound (10.5 g, white powder). Yield 37.6%.
¹ H-NMR (300 MHz, CDCl ₃ , TMS) δ: 1.25-1.98 (m, 22H), 6.28 (d, 1H, J _HP = 433.6 Hz).
³¹ P-NMR (121 MHz, CDCl ₃ , 85% H ₃ PO ₄ ) δ: 50.07 (d, J _HP = 433.5 Hz).

Reference example 4

窒素気流下、マグネシウム（19.45 g, 4.00 当量）および少量のヨウ素、1,2-ジブロモエタンのテトラヒドロフラン（140mL）溶液を室温で30分間撹拌した。1-ブロモ-4-メトキシベンゼン（151.47 g, 4.00 当量）のテトラヒドロフラン（650mL）溶液を25〜30℃で加えた後、40℃で1時間撹拌した。ついで25〜30℃で亜リン酸ジエチル（27.71 g, 0.20 mol）のテトラヒドロフラン（60 mL）溶液を加えた。0〜5℃で6M-HCl（110 mL）を加え、ついで水（110 mL）、トルエン（110 mL）を加えた。反応液を分液し、有機層を水（110 mL）、5% NaHCO₃水溶液（110 mL）、5% NaCl水溶液（110 mL）で順次洗浄し、有機層を硫酸マグネシウム（25 g）で乾燥後、減圧濃縮した。残渣をn-ヘキサンより再結晶し、乾燥後（減圧、40℃）、表題化合物（15.71 g, 白色粉末）を得た、収率30.0%
¹H-NMR (300MHz, CDCl₃, TMS) δ: 3.85 (s, 6H), 6.98 (d, 2H, J = 2.1 Hz), 7.01 (d, 2H, J = 2.1Hz), 7.57 (s, 1H), 7.60 (s, 1H), 7.62 (s, 1H), 7.65 (s, 1H), 8.03 (d, 1H, J_H-P = 477 Hz).
¹³C-NMR (75MHz, CDCl₃, CDCl₃) δ: 55.31, 114.29, 114.28, 122.27, 123.70, 132.51, 132.68, 162.87.
³¹P-NMR (121MHz, CDCl₃, 85%H₃PO₄) δ: 21.19 (dq, J_H-P = 477 Hz, J_H-CCP = 13Hz). Diparamethoxyphenylphosphine oxide

Under a nitrogen stream, a solution of magnesium (19.45 g, 4.00 equivalent), a small amount of iodine and 1,2-dibromoethane in tetrahydrofuran (140 mL) was stirred at room temperature for 30 minutes. A solution of 1-bromo-4-methoxybenzene (151.47 g, 4.00 equivalent) in tetrahydrofuran (650 mL) was added at 25-30 ° C., and the mixture was stirred at 40 ° C. for 1 hr. Then, a solution of diethyl phosphite (27.71 g, 0.20 mol) in tetrahydrofuran (60 mL) was added at 25-30 ° C. 6M-HCl (110 mL) was added at 0 to 5 ° C., and then water (110 mL) and toluene (110 mL) were added. The reaction mixture was separated, and the organic layer was washed successively with water (110 mL), 5% aqueous NaHCO ₃ solution (110 mL), 5% aqueous NaCl solution (110 mL), and the organic layer was dried over magnesium sulfate (25 g). Then, it concentrated under reduced pressure. The residue was recrystallized from n-hexane and dried (reduced pressure, 40 ° C.) to give the title compound (15.71 g, white powder), yield 30.0%
¹ H-NMR (300 MHz, CDCl ₃ , TMS) δ: 3.85 (s, 6H), 6.98 (d, 2H, J = 2.1 Hz), 7.01 (d, 2H, J = 2.1 Hz), 7.57 (s, 1H ), 7.60 (s, 1H), 7.62 (s, 1H), 7.65 (s, 1H), 8.03 (d, 1H, J _HP = 477 Hz).
¹³ C-NMR (75 MHz, CDCl ₃ , CDCl ₃ ) δ: 55.31, 114.29, 114.28, 122.27, 123.70, 132.51, 132.68, 162.87.
³¹ P-NMR (121 MHz, CDCl ₃ , 85% H ₃ PO ₄ ) δ: 21.19 (dq, J _HP = 477 Hz, J _H-CCP = 13 Hz).

アルゴン雰囲気下、室温 (25℃)でジフェニルホスフィンオキサイド (0.4078 g, 2.0 mmol)にトルエン2 mL及びテトラヒドロフラン1 mLを加えて懸濁撹拌した。ついで1.02mol/Lのボラン-テトラヒドロフラン錯体(6 mL, 3.06 当量)を加えた。反応液を減圧濃縮後、トルエンに溶解し、シリカゲルカラムクロマトグラフィー（シリカゲル25 g、トルエン）にて精製し、有効区分を減圧濃縮した。残渣をn-ヘキサンより再結晶し、乾燥後(減圧、40℃)、表題化合物 (0.2982 g、澄明オイル)を得た。収率70.3%。
¹H-NMR (300MHz, CDCl₃, TMS)δ: 0.51-1.75 (m, 3H), 6.31 (dq, 1H, J_H-P = 378.7 Hz, J = 7.0 Hz), 7.42-7.52 (m, 6H), 7.64-7.71 (m, 4H).
¹³C-NMR (75MHz, CDCl₃, CDCl₃)δ: 125.50, 126.26, 128.66, 128.80, 131.28, 131.31, 132.54, 132.67.
³¹P-NMR (121MHz, CDCl₃, 85%H₃PO₄) δ: 0.69-1.69 (m), 3.83-4.83 (m) Diphenylphosphine-borane complex

Under argon atmosphere, 2 mL of toluene and 1 mL of tetrahydrofuran were added to diphenylphosphine oxide (0.4078 g, 2.0 mmol) at room temperature (25 ° C.), and the mixture was suspended and stirred. Then 1.02 mol / L borane-tetrahydrofuran complex (6 mL, 3.06 equivalent) was added. The reaction solution was concentrated under reduced pressure, dissolved in toluene, and purified by silica gel column chromatography (silica gel 25 g, toluene), and the effective fraction was concentrated under reduced pressure. The residue was recrystallized from n-hexane and dried (reduced pressure, 40 ° C.) to obtain the title compound (0.2982 g, clear oil). Yield 70.3%.
¹ H-NMR (300MHz, CDCl ₃ , TMS) δ: 0.51-1.75 (m, 3H), 6.31 (dq, 1H, J _HP = 378.7 Hz, J = 7.0 Hz), 7.42-7.52 (m, 6H), 7.64-7.71 (m, 4H).
¹³ C-NMR (75 MHz, CDCl ₃ , CDCl ₃ ) δ: 125.50, 126.26, 128.66, 128.80, 131.28, 131.31, 132.54, 132.67.
³¹ P-NMR (121MHz, CDCl ₃ , 85% H ₃ PO ₄ ) δ: 0.69-1.69 (m), 3.83-4.83 (m)

アルゴン雰囲気下、参考例１で合成したビス(p-トリル)ホスフィンオキサイド(7.11 g, 30.9 mmol)に室温 (25℃)でトルエン32 mLを加えて懸濁撹拌した。ついで1.02 mol/Lのボラン-テトラヒドロフラン錯体(100 mL, 3.30 当量)を加えた。反応液を減圧濃縮後、トルエンに溶解し、シリカゲルカラムクロマトグラフィー（シリカゲル25 g、トルエン）にて精製し、有効区分を減圧濃縮した。残渣をn-ヘキサンより再結晶し、乾燥後 (減圧、40℃)、表題化合物 (6.44g、白色粉末)を得た。収率91.4%。
¹H-NMR (300MHz, CDCl₃, TMS) δ: 0.45-1.65 (m, 3H), 2.37 (s, 6H), 6.24 (dq, 1H, J_H-P = 377.5 Hz, J = 6.6 Hz), 7.22-7.25 (m, 4H), 7.49-7.56 (m, 4H).
³¹P-NMR (121MHz, CDCl₃, 85%H₃PO₄) δ: -1.43- -0.18 (m), 1.81-3.00 (m). Di (p-tolyl) phosphine-borane complex

Under an argon atmosphere, 32 mL of toluene was added to bis (p-tolyl) phosphine oxide (7.11 g, 30.9 mmol) synthesized in Reference Example 1 at room temperature (25 ° C.), and the mixture was suspended and stirred. Then 1.02 mol / L borane-tetrahydrofuran complex (100 mL, 3.30 eq) was added. The reaction solution was concentrated under reduced pressure, dissolved in toluene, and purified by silica gel column chromatography (silica gel 25 g, toluene), and the effective fraction was concentrated under reduced pressure. The residue was recrystallized from n-hexane and dried (reduced pressure, 40 ° C.) to obtain the title compound (6.44 g, white powder). Yield 91.4%.
¹ H-NMR (300MHz, CDCl ₃ , TMS) δ: 0.45-1.65 (m, 3H), 2.37 (s, 6H), 6.24 (dq, 1H, J _HP = 377.5 Hz, J = 6.6 Hz), 7.22- 7.25 (m, 4H), 7.49-7.56 (m, 4H).
³¹ P-NMR (121MHz, CDCl ₃ , 85% H ₃ PO ₄ ) δ: -1.43- -0.18 (m), 1.81-3.00 (m).

アルゴン雰囲気下、参考例２で合成したジナフチルホスフィンオキサイド(0.6061 g, 2.00 mmol)に室温（25℃）でトルエン4 mLを加えて懸濁撹拌した。ついで1.02 mol/Lのボラン-テトラヒドロフラン錯体(5 mL, 2.55 当量)を加えた。反応液をシリカゲルカラムクロマトグラフィー（シリカゲル15 g、トルエン）にて精製し、有効区分を減圧濃縮した。残渣を乾燥後(減圧、40℃)、表題化合物（0.4577 g、白色粉末）を得た。収率76.2%。
¹H-NMR (300MHz, CDCl₃, TMS) δ: 0.60-1.85 (m, 3H), 6.56 (dq, 1H, J_H-P= 378.7 Hz, J = 6.9 Hz), 7.52-8.31 (m, 14H).
¹³C-NMR (75MHz, CDCl₃, CDCl₃) δ: 124.40, 125.16, 128.53, 129.22, 129.31, 129.61, 129.96, 130.30, 130.43, 134.20, 134.36, 135.91, 135.94, 135.99, 136.14.
³¹P-NMR (121MHz, CDCl₃, 85%H₃PO₄) δ: 1.10-2.21 (m), 3.92-4.95 (m). Dinaphthylphosphine-borane complex

Under an argon atmosphere, 4 mL of toluene was added to the dinaphthylphosphine oxide (0.6061 g, 2.00 mmol) synthesized in Reference Example 2 at room temperature (25 ° C.), and the mixture was suspended and stirred. Then 1.02 mol / L borane-tetrahydrofuran complex (5 mL, 2.55 eq) was added. The reaction solution was purified by silica gel column chromatography (silica gel 15 g, toluene), and the effective fraction was concentrated under reduced pressure. The residue was dried (reduced pressure, 40 ° C.) to give the title compound (0.4577 g, white powder). Yield 76.2%.
¹ H-NMR (300 MHz, CDCl ₃ , TMS) δ: 0.60-1.85 (m, 3H), 6.56 (dq, 1H, J _HP = 378.7 Hz, J = 6.9 Hz), 7.52-8.31 (m, 14H).
¹³ C-NMR (75 MHz, CDCl ₃ , CDCl ₃ ) δ: 124.40, 125.16, 128.53, 129.22, 129.31, 129.61, 129.96, 130.30, 130.43, 134.20, 134.36, 135.91, 135.94, 135.99, 136.14.
³¹ P-NMR (121MHz, CDCl ₃ , 85% H ₃ PO ₄ ) δ: 1.10-2.21 (m), 3.92-4.95 (m).

アルゴン雰囲気下、参考例３で合成したジシクロヘキシルホスフィンオキサイド (0.1106 g, 0.50 mmol)に室温（25℃）でトルエン1 mLを加えて溶解した。ついで1.02 mol/Lのボラン-テトラヒドロフラン錯体(1.5 mL, 3.06 当量)を加えた。反応液を減圧濃縮後、トルエンに溶解し、シリカゲルカラムクロマトグラフィー（シリカゲル10 g、トルエン）にて精製し、有効区分を減圧濃縮した。残渣をn-ヘキサンより再結晶し、乾燥後(減圧、40℃)、表題化合物(0.05 g、白色粉末)を得た。収率4.3%。
¹H-NMR (300MHz, CDCl₃, TMS) δ: 0.25-0.95 (m, 3H), 1.27-1.90 (m, 22H), 4.13 (dq, 1H, J_H-P = 351.1 Hz, J = 4.7 Hz).
³¹P-NMR (121MHz, CDCl₃, 85%H₃PO₄) δ: 16.20-17.54 (m), 18.98-20.31 (m). Dicyclohexylphosphine-borane complex

Under argon atmosphere, 1 mL of toluene was added to and dissolved in dicyclohexylphosphine oxide (0.1106 g, 0.50 mmol) synthesized in Reference Example 3 at room temperature (25 ° C.). Then 1.02 mol / L borane-tetrahydrofuran complex (1.5 mL, 3.06 equivalent) was added. The reaction solution was concentrated under reduced pressure, dissolved in toluene, purified by silica gel column chromatography (silica gel 10 g, toluene), and the effective category was concentrated under reduced pressure. The residue was recrystallized from n-hexane and dried (reduced pressure, 40 ° C.) to obtain the title compound (0.05 g, white powder). Yield 4.3%.
¹ H-NMR (300 MHz, CDCl ₃ , TMS) δ: 0.25-0.95 (m, 3H), 1.27-1.90 (m, 22H), 4.13 (dq, 1H, J _HP = 351.1 Hz, J = 4.7 Hz).
³¹ P-NMR (121MHz, CDCl ₃ , 85% H ₃ PO ₄ ) δ: 16.20-17.54 (m), 18.98-20.31 (m).

アルゴン雰囲気下、参考例４で合成したジパラメトキシフェニルホスフィンオキサイド (13.11 g, 0.17 mmol)に室温（25℃）でトルエン80 mLを加えて溶解した。ついで1.02 mol/Lのボラン-テトラヒドロフラン錯体(165 mL, 3.30 当量)を2時間で加えた。反応液にシリカゲル（20 g）を加えた後、ろ別し、減圧濃縮後した。残渣をn-ヘキサンより再結晶し、乾燥後(減圧、40℃)、表題化合物(11.1 g、白色粉末)を得た。収率85%。
¹H-NMR (300MHz, CDCl₃, TMS) δ: 0.26-1.65 (m, 3H), 3.83 (s, 6H), 6.26 (dm, 1H, J_H-P = 378 Hz), 6.94 (s, 1H), 6.95 (s, 1H), 6.96 (s, 1H), 6.97 (s, 1H), 7.55 (s, 1H), 7.57 (s, 1H), 7.58 (s, 1H), 7.61 (s, 1H).
¹³C-NMR (75MHz, CDCl₃, CDCl₃) δ: 55.30, 114.59, 114.74, 116.84, 117.67, 134.43, 134.57, 162.23.
³¹P-NMR (121MHz, CDCl₃, 85%H₃PO₄) δ: -4.5-(-3.2) (m), -1.6-0.4 (m). Diparamethoxyphenylphosphine-borane complex

Under an argon atmosphere, 80 mL of toluene was added to and dissolved in diparamethoxyphenylphosphine oxide (13.11 g, 0.17 mmol) synthesized in Reference Example 4 at room temperature (25 ° C.). Then 1.02 mol / L borane-tetrahydrofuran complex (165 mL, 3.30 eq) was added over 2 hours. Silica gel (20 g) was added to the reaction mixture, and the mixture was filtered and concentrated under reduced pressure. The residue was recrystallized from n-hexane and dried (reduced pressure, 40 ° C.) to obtain the title compound (11.1 g, white powder). Yield 85%.
¹ H-NMR (300MHz, CDCl ₃ , TMS) δ: 0.26-1.65 (m, 3H), 3.83 (s, 6H), 6.26 (dm, 1H, J _HP = 378 Hz), 6.94 (s, 1H), 6.95 (s, 1H), 6.96 (s, 1H), 6.97 (s, 1H), 7.55 (s, 1H), 7.57 (s, 1H), 7.58 (s, 1H), 7.61 (s, 1H).
¹³ C-NMR (75 MHz, CDCl ₃ , CDCl ₃ ) δ: 55.30, 114.59, 114.74, 116.84, 117.67, 134.43, 134.57, 162.23.
³¹ P-NMR (121MHz, CDCl ₃ , 85% H ₃ PO ₄ ) δ: -4.5-(-3.2) (m), -1.6-0.4 (m).

As described above, according to the present invention, a phosphine-borane complex used for the synthesis of an organophosphorus compound can be produced under mild conditions and in a high yield.

Claims (8)

formula

[Wherein R ¹ , R ² and R ³ are the same or different and (i) a hydrogen atom, (ii) a halogen atom, (iii) (1) nitro, (2) nitroso, (3) cyano, (4) Hydroxy, (5) C _1-6 alkoxy group, (6) formyl, (7) C _1-6 alkyl-carbonyl group, (8) C _1-6 alkoxy-carbonyl group, (9) carboxyl, (10) N -Mono C _1-6 alkyl-carbamoyl group, (11) N, N-diC _1-6 alkyl-carbamoyl group, (12) halogen atom, (13) mono-C _1-6 alkylamino group, and (14 ) An alkyl group _{optionally having} 1 to 3 substituents selected from di-C _1-6 alkylamino groups at substitutable positions ; (iv) (1) nitro, (2) nitroso, (3 ) Cyano, (4) hydroxy, (5 C _1-6 alkoxy group, (6) formyl, _{(7) C 1-6} alkyl - carbonyl group, _{(8) C 1-6} alkoxy - carbonyl group, (9) carboxy, (10) N-mono _{C 1- 6} alkyl-carbamoyl groups, (11) N, N-diC _1-6 alkyl-carbamoyl groups, (12) halogen atoms, (13) mono-C _1-6 alkylamino groups, and (14) di-C _{1 A} cycloalkyl group _{optionally having} 1 to 3 substituents selected from _-6 alkylamino groups at substitutable positions , (v) (1) nitro, (2) nitroso, (3) cyano, ( 4) hydroxy, (5) C _1-6 alkyl group, (6) C _1-6 alkoxy group, (7) formyl, (8) C _1-6 alkyl-carbonyl group, (9) C _1-6 alkoxy- Carbonyl group, (10) carboxy (11) N-monoC _1-6 alkyl-carbamoyl group, (12) N, N-diC _1-6 alkyl-carbamoyl group, (13) halogen atom, (14) mono-C _1-6 alkyl 1 to 5 substituents selected from an amino group, (15) di-C _1-6 alkylamino group, and (16) halogeno-C _1-6 alkyl group may be present at substitutable positions. An aryl group or (vi) (1) nitro, (2) nitroso, (3) cyano, (4) hydroxy, (5) C _1-6 alkyl group, (6) C _1-6 alkoxy group, (7) formyl (8) C _1-6 alkyl-carbonyl group, (9) C _1-6 alkoxy-carbonyl group, (10) carboxyl, (11) N-monoC _1-6 alkyl-carbamoyl group, (12) N, N- _{di-C 1-6} alkyl - Cal Moil group, selected from (13) a halogen atom, (14) mono _{-C 1-6} alkylamino group, (15) di _{-C 1-6} alkylamino group, and (16) halogeno _{-C 1-6} alkyl group A heterocyclic group optionally having 1 to 5 substituents at substitutable positions ] or a salt thereof and a borane reagent (provided that the borane reagent is other than dimethylsulfide borane) Characterized by reacting in a solvent

[In the formula, each symbol is as defined above] A process for producing a phosphine-borane complex or a salt thereof . The process according to claim 1, wherein R ³ is a hydrogen atom. R ¹ and R ² are the same or different and (i) a hydrogen atom, (ii) a halogen atom, (iii) (1) nitro, (2) nitroso, (3) cyano, (4) hydroxy, (5) C _{1 -6} alkoxy group, (6) formyl, (7) C _1-6 alkyl-carbonyl group, (8) C _1-6 alkoxy-carbonyl group, (9) carboxyl, (10) N-monoC _1-6 alkyl -Carbamoyl group, (11) N, N-diC _1-6 alkyl-carbamoyl group, (12) halogen atom, (13) mono-C _1-6 alkylamino group, and (14) di-C _1-6. An alkyl group optionally having 1 to 3 substituents selected from alkylamino groups at substitutable positions ; (iv) (1) nitro, (2) nitroso, (3) cyano, (4) hydroxy (5) C _1-6 Arco Xyl group, (6) formyl, (7) C _1-6 alkyl-carbonyl group, (8) C _1-6 alkoxy-carbonyl group, (9) carboxyl, (10) N-monoC _1-6 alkyl-carbamoyl Groups, (11) N, N-diC _1-6 alkyl-carbamoyl group, (12) halogen atom, (13) mono-C _1-6 alkylamino group, and (14) di-C _1-6 alkylamino group A cycloalkyl group optionally having 1 to 3 substituents selected from a group at substitutable positions , (v) (1) nitro, (2) nitroso, (3) cyano, (4) hydroxy, (5) C _1-6 alkyl group, (6) C _1-6 alkoxy group, (7) formyl, (8) C _1-6 alkyl-carbonyl group, (9) C _1-6 alkoxy-carbonyl group, 10) Carboxyl, (11) N Mono _{C 1-6} alkyl - carbamoyl group, (12) N, _{N-di-C 1-6} alkyl - carbamoyl group, (13) a halogen atom, (14) mono _{-C 1-6} alkylamino group, (15) di -C _1-6 alkylamino group, and (16) halogeno _{-C 1-6} to 1 selected from an alkyl group five substituents which may have a substitutable position aryl group or (vi) ( 1) Nitro, (2) Nitroso, (3) Cyano, (4) Hydroxy, (5) C _1-6 alkyl group, (6) C _1-6 alkoxy group, (7) Formyl, (8) C _{1- 6} alkyl-carbonyl group, (9) C _1-6 alkoxy-carbonyl group, (10) carboxyl, (11) N-monoC _1-6 alkyl-carbamoyl group, (12) N, N-diC _1-6 An alkyl-carbamoyl group, (1 ) Halogen atom, (14) mono _{-C 1-6} alkylamino group, (15) di _{-C 1-6} alkylamino group, and (16) to 1 selected from halogeno _{-C 1-6} alkyl group five A heterocyclic group which may have a substituent at a substitutable position , R ³ is (i) a halogen atom, (ii) (1) nitro, (2) nitroso, (3) cyano, (4) hydroxy, (5) C _1-6 alkoxy group, (6) formyl, (7) C _1-6 alkyl-carbonyl group, (8) C _1-6 alkoxy-carbonyl group, (9) carboxyl, (10) N-mono A C _1-6 alkyl-carbamoyl group, (11) N, N-diC _1-6 alkyl-carbamoyl group, (12) a halogen atom, (13) a mono-C _1-6 alkylamino group, and (14) di -C from _1-6 alkylamino group Barrel (1) to three substituents substitutable alkyl group that may have a position, (iii) (1) nitro, (2) nitroso, (3) cyano, (4) hydroxy, (5) C _1-6 alkoxy group, (6) formyl, (7) C _1-6 alkyl-carbonyl group, (8) C _1-6 alkoxy-carbonyl group, (9) carboxyl, (10) N-mono C _1-6 An alkyl-carbamoyl group, (11) N, N-diC _1-6 alkyl-carbamoyl group, (12) a halogen atom, (13) mono-C _1-6 alkylamino group, and (14) di-C _{1- A} cycloalkyl group optionally having 1 to 3 substituents selected from ₆ alkylamino groups at substitutable positions , (iv) (1) nitro, (2) nitroso, (3) cyano, (4 ) hydroxy, _{(5) C 1-6} Alkyl group, _{(6) C 1-6} alkoxy group, (7) formyl, _{(8) C 1-6} alkyl - carbonyl group, _{(9) C 1-6} alkoxy - carbonyl group, (10) carboxyl, (11) N-mono C _1-6 alkyl-carbamoyl group, (12) N, N-diC _1-6 alkyl-carbamoyl group, (13) halogen atom, (14) mono-C _1-6 alkylamino group, (15 ) di _{-C 1-6} alkylamino group, and (16) halogeno _{-C 1-6} alkyl to 1 selected from group five substituents which may have a substitutable position aryl group or (v ) (1) Nitro, (2) Nitroso, (3) Cyano, (4) Hydroxy, (5) C _1-6 alkyl group, (6) C _1-6 alkoxy group, (7) Formyl, (8) C _1-6 alkyl - carbonyl group, (9 C _1-6 alkoxy - carbonyl group, (10) carboxyl, (11) N-mono _{C 1-6} alkyl - carbamoyl group, (12) N, _{N-di-C 1-6} alkyl - carbamoyl group, (13) halogen 1 to 5 substituents selected from an atom, (14) mono-C _1-6 alkylamino group, (15) di-C _1-6 alkylamino group, and (16) halogeno-C _1-6 alkyl group The production method according to claim 1, which is a heterocyclic group optionally having a substitutable position . R ¹ and R ² are the same or different and (1) nitro, (2) nitroso, (3) cyano, (4) hydroxy, (5) C _1-6 alkyl group, (6) C _1-6 alkoxy group, (7) formyl, (8) C _1-6 alkyl-carbonyl group, (9) C _1-6 alkoxy-carbonyl group, (10) carboxyl, (11) N-monoC _1-6 alkyl-carbamoyl group, 12) N, N-diC _1-6 alkyl-carbamoyl group, (13) halogen atom, (14) mono-C _1-6 alkylamino group, (15) di-C _1-6 alkylamino group, and ( 16) the process according to claim 2 or 3, wherein the halogeno -C _1-6 1 to five substituents which may have a substitutable position aryl group selected from alkyl groups. R ¹ and R ² are the same or different and each represents 1 to 5 C _1-6 alkyl group, C _1-6 alkoxy group, halogen atom, mono C _1-6 alkylamino group or diC _1-6 alkylamino group. The production method according to claim 4, which is phenyl which may be substituted. The process according to claim 2 or 3, wherein R ¹ and R ² are the same or different and are a C _1-6 alkyl group or a C _3-6 cycloalkyl group.   The process according to claim 1, wherein the borane reagent is a borane-tetrahydrofuran complex or a borane-amine complex.   The process according to claim 1, wherein the borane reagent is a borane-tetrahydrofuran complex.