JP2868199B2 - Method for producing pentafluorophenyl alkali metal salt using pentafluorobenzene in a chain ether solvent - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for efficiently producing pentafluorophenyl alkali metal salts using pentafluorobenzene as a raw material. The pentafluorophenyl alkali metal salt obtained in the present invention is reacted with various pharmaceutical intermediates or boron compounds such as boron chloride to form a boron derivative extremely useful as a cocatalyst for cationic complex polymerization, for example, tris (pentafluorophenyl). It is used as an important reactant when producing boron or tetrakis (pentafluorophenyl) borate derivatives.

[0002]

2. Description of the Related Art An alkali metal salt of pentafluorophenyl is reacted with a boron compound such as boron chloride to form a boron derivative, for example, tris (pentafluorophenyl), which is extremely useful as a catalyst component for a polymerization reaction. It is used as an important reagent for introducing a pentafluorophenyl group into boron when producing phenyl) boron. (Eg, Synthesis of Fluoroorg
anic Compounds, p.190, Springer-Verlag (1985))

[0003] To date, several pentafluorophenyl alkali metal salt synthesis reactions are known. For example, a method for producing pentafluorophenyllithium by performing a bromine-metal exchange reaction using relatively expensive pentafluorobromobenzene and butyllithium as starting materials for a pentafluorophenyl group source has already been known. For example, Synthesis of Fluoroorganic Compounds, p. 190,
Springer-Verlag (1985) prepares pentafluorophenyllithium in diethyl ether-hexane at -70 ° C and reacts with sulfur dioxide to obtain lithium pentafluorophenylsulfenate in 94% yield.

[0004] Further, a method of using pentafluorobenzene as a starting material of a pentafluorophenyl group source and performing a hydrogen-metal exchange reaction with butyllithium to produce pentafluorophenyllithium is already known. For example, in J. Org. Chem., 2385, 29 (1964), pentafluorophenyllithium prepared from pentafluorobenzene and butyllithium is reacted with carbon dioxide to obtain a reaction solvent system with a purification yield, although the reaction yield is unknown. As a result, pentafluorobenzoic acid was obtained in a yield of 68% in a diethyl ether-hexane system, 80.9% in a diethyl ether system and 82% in a diethyl ether-tetrahydrofuran system. In J. Org. Chem., 4229, 31 (1966), pentafluorophenyllithium prepared from pentafluorobenzene and butyllithium was reacted with hexafluoroacetone to obtain a 79% purification yield, although the reaction yield was unknown. Undecafluoro-2-phenyl-2-propanol was obtained at a rate.

[0005] Pentafluorobromobenzene has higher reactivity with organometallic compounds such as butyllithium than pentafluorobenzene. When pentafluorophenyllithium is produced by performing a hydrogen-metal exchange reaction using butyllithium, the reaction takes about 5 minutes in a chain ether solvent such as diethyl ether or a cyclic ether solvent such as tetrahydrofuran. Completely and almost quantitatively, pentafluorophenyllithium is produced. However, since pentafluorobromobenzene is obtained by brominating pentafluorobenzene, the price is high. In other words, industrially, it is desired to use cheaper pentafluorobenzene.

However, since pentafluorobenzene has lower reactivity than pentafluorobromobenzene, when pentafluorophenyllithium is produced by deprotonation reaction using butyllithium, pentafluorobenzene is less reactive than a linear ether solvent. The addition of a cyclic ether solvent such as tetrahydrofuran to a chain ether solvent can also improve the yield. J. Org. Chem., 2835, 2
9 (1964).

In general, it is known that an organometallic compound such as butyllithium reacts with an ether solvent at a temperature of 0 ° C. or higher. Therefore, organometallic compounds such as butyllithium are usually commercially sold as solutions of saturated hydrocarbon solvents such as hexane, cyclohexane and pentane. Accordingly, when pentafluorobenzene is produced in a chain ether-based solvent using a butyllithium solution of a commercially available saturated hydrocarbon-based solvent such as hexane, pentafluorophenyllithium is diluted with butyllithium. Is mixed into the reaction system, the chain ether solvent-
It becomes a mixed solvent of hydrocarbon-based solvents, and the reaction hardly occurs. (See, for example, J. Org. Chem., 2385, 29 (196
Four))

On the other hand, when a compound having a very strong Lewis acidity, such as tris (pentafluorophenyl) boron, is produced, if a cyclic ether solvent is present in the reaction system, the cyclic ether is added to the product by strong coordination force. Often, a coordinated complex is formed, making removal difficult.

[0009]

In view of the above situation, the present inventors have developed a reaction solvent system which uses pentafluorobenzene as a starting material for a pentafluorophenyl group source and does not use a cyclic ether solvent such as tetrahydrofuran. The present inventors have conducted various studies on a method for producing a pentafluorophenyl alkali metal salt with high reproducibility and high yield, and have reached the present invention.

That is, the gist of the present invention is that 0.5 to 1.5 equivalents of the organometallic compound represented by the formula [II] is added to one chain equivalent of pentafluorobenzene represented by the formula [I]. -120 in a solvent mixture, a hydrocarbon solvent or a mixed solvent of a chain ether solvent and a hydrocarbon solvent.
The present invention relates to a production method for generating a pentafluorophenyl alkali metal salt represented by the formula [III] by reacting at a temperature of from 80 ° C to 80 ° C.

[0011]

Hereinafter, the present invention will be described in detail. The chain ether solvent referred to in the present invention is diethyl ether, dipropyl ether, diisopropyl ether, dibutyl ether, diisoamyl ether, 1,2-dimethoxyethane, 1,2-diethoxyethane, di-2-methoxyethyl. Indicates ether and the like.

The cyclic ether solvent used in the present invention includes tetrahydrofuran, tetrahydropyran, 1,4-dioxane and the like.

[0013] Next, the hydrocarbon solvent referred to in the present invention is pentane, isopentane, hexane, cyclohexane, heptane, octane, nonane, decane, undecane, dodecane, tridecane, tetradecane, pentadecane, hexadecane, n-paraffin or petroleum ether. Such as benzene, toluene, o-xylene, m-
Xylene, p-xylene, 1,2,3-trimethylbenzene, 1,2,4-trimethylbenzene, 1,2,5-
Aromatic hydrocarbons such as trimethylbenzene, 1,3,5-trimethylbenzene, ethylbenzene, propylbenzene and butylbenzene, and mixtures thereof are shown.

Next, in the formula [II] of the present invention, the functional groups which do not affect the reaction include methyl group, ethyl group,
Propyl, isopropyl, propenyl, 2-isopropenyl, allyl, butyl, sec-butyl,
tert-butyl, isobutyl, pentyl, sec-pentyl, tert-pentyl, neo-pentyl, isopentyl, hexyl, sec-hexyl, isohexyl, sec-isohexyl, cyclohexyl, phenyl Benzyl group, o-tolyl group, m-tolyl group,
p-tolyl group, methoxymethyl group, methylthiomethyl group, 2-dimethylaminoethyl group, o-anis group, m-
Examples of the organometallic compound represented by the formula [II] include an anis group, a p-anis group, and a trimethylsilylmethyl group, and examples of the organometallic compound include methyllithium, ethyllithium, and propyllithium.
Isopropyl lithium, butyl lithium, isobutyl lithium, sec-butyl lithium, tert-butyl lithium, pentyl lithium, isopentyl lithium, sec-
Pentyl lithium, tert-pentyl lithium, sec-isopentyl lithium, hexyl lithium, isohexyl lithium, sec-hexyl lithium, cyclohexyl lithium, phenyl lithium, o-tolyl lithium, m-
There are tolyl lithium, p-tolyl lithium, trimethylsilyl lithium, phenyl sodium, o-tolyl sodium, m-tolyl sodium, p-tolyl sodium, butyl lithium / potassium tert-butoxide or butyl lithium / sodium tert-butoxide. , Strong basic isopropyl lithium, sec-
Butyllithium, tert-butyllithium, sec-pentyllithium, tert-pentyllithium, sec-isopentyllithium, sec-hexyllithium, cyclohexyllithium, butyllithium / potassium tert-butoxide or butyllithium / sodium tert-butoxide. .

The specific method of manufacturing will be described below in order. A solution of the pentafluorobenzene represented by the formula [I] in an ether solvent, a hydrocarbon solvent or a mixed solvent of an ether solvent and a hydrocarbon solvent is added in an amount of 0.5 to 1.5 equivalents to 1 equivalent of pentafluorobenzene. Formula [II]
When the pentafluorophenyl alkali metal salt represented by the formula [III] is generated by reacting the organometallic compound represented by the formula at -120 ° C. to 80 ° C., the pentafluoro compound represented by the formula [I] If the amount of the organometallic compound represented by the formula [II] is too small than that of benzene, a large amount of unreacted pentafluorobenzene remains, and if it is used in excess, the pentafluorophenyl metal salt represented by the formula [III] is formed. Because halogen and metal exchange reaction may occur with fluorine.
It is desirable to use 0.8 to 1.20 equivalents of the organometallic compound represented by the formula [II]. When the reaction temperature is lower than -80 ° C, the reaction proceeds extremely slowly. When the reaction temperature is higher than 0 ° C, the side reaction proceeds. Is very fast and in each case the yield is very low. Therefore, it is desirable that the reaction is carried out in the range of -80 ° C to 0 ° C. The reaction mixture is reacted at the same temperature for 5 to 120 minutes to prepare an alkali metal salt of pentafluorophenyl represented by the formula [III].

The pentafluorophenyl alkali metal salt represented by the formula [III] produced here is C ₆ F ₅ Li, C
₆ F ₅ Na, a C ₆ F ₅ K.

[0017]

Industrial Applicability The present invention relates to an alkali metal pentafluorophenyl which is an important reactant for producing a compound such as tris (pentafluorophenyl) borane, which is a cocatalyst for preparing a cationic complex polymerization catalyst. This is valuable in that it can provide a method for producing a salt from a less expensive pentafluorobenzene instead of pentafluorobenzene bromide in a chain ether-based solvent at a high yield.

[0018]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples. However, this is an example for specifically explaining the present invention, and the present invention is not limited by the following examples. is not. The reaction yield is determined by gas chromatography of pentafluorotoluene produced by reacting with a large excess of methyl iodide, or by gas chromatography of pentafluorobenzoic acid produced by blowing carbon dioxide, or 0.25 equivalents. Of N, N-dimethylanilinium tetrakis (pentafluorophenyl) borate produced by counter cation exchange with N, N-dimethylanilinium chloride after reaction with boron trichloride, and quantification by ¹⁹ F-NMR Value.

Example 1 A 100 ml glass three-necked flask was equipped with a 50 ml glass dropping funnel, a temperature resistor, and a septum rubber, and the system was sufficiently purged with nitrogen. 5 g (29.8 mmol) of pentafluorobenzene and 30 ml of diethyl ether are charged into the flask, and the solution is cooled to -65 ° C.
Thereafter, 12.3 g (29.8 mmol) of a 15.5 wt% tert-butyl lithium pentane solution charged in the dropping funnel was cooled to −
Add dropwise while not exceeding 55 ° C. After dropping,
Stir at -65 to -55 ° C to prepare pentafluorophenyl lithium. A solution of the prepared pentafluorophenyllithium was added to a solution of methyl iodide in tetrahydrofuran at -55.
After adding at -65 ° C and stirring at the same temperature for 30 minutes, the temperature was gradually raised to room temperature, and pentafluorotoluene was determined by gas chromatography to be 97.1%.

Example 2 A 100 ml glass three-necked flask was equipped with a 50 ml glass dropping funnel, a temperature resistor and a septum rubber, and the system was sufficiently purged with nitrogen. 5 g (29.8 mmol) of pentafluorobenzene and 30 ml of diethyl ether are charged into the flask, and the solution is cooled to -65 ° C.
Thereafter, 14.2 g (34.3 mmol) of a 15.5 wt% sec-butyl lithium hexane solution charged in the dropping funnel was cooled to −
Add dropwise while not exceeding 55 ° C. After dropping,
Stir at -65 to -55 ° C to prepare pentafluorophenyl lithium. Carbon dioxide was blown into the prepared solution of pentafluorophenyllithium, and the yield of pentafluorobenzoic acid determined by gas chromatography was 9%.
It was 6.8%.

Example 3 A 50 ml glass dropping funnel, a temperature resistor and a septum rubber were attached to a 100 ml glass three-necked flask, and the inside of the system was sufficiently purged with nitrogen. 5 g (29.8 mmol) of pentafluorobenzene and 30 ml of diethyl ether are charged into the flask, and the solution is cooled to -65 ° C.
Thereafter, 12.3 g (29.8 mmol) of a 16.1 wt% sec-butyllithium hexane solution charged in the dropping funnel was cooled to −
Add dropwise while not exceeding 55 ° C. After dropping,
Stir at -65 to -55 ° C to prepare pentafluorophenyl lithium. Carbon dioxide was blown into the prepared solution of pentafluorophenyllithium, and the yield of pentafluorobenzoic acid determined by gas chromatography was 9%.
It was 6.8%.

Example 4 A 100 ml glass three-necked flask was equipped with a 50 ml glass dropping funnel, a temperature resistor and a septum rubber, and the system was sufficiently purged with nitrogen. 5 g (29.8 mmol) of pentafluorobenzene and 30 ml of diethyl ether are charged into the flask, and the solution is cooled to -65 ° C.
Then, 12.3 g (29.8 mmol) of a 16.1 wt% tert-butyl lithium pentane solution charged in the dropping funnel was cooled to −
Add dropwise while not exceeding 55 ° C. After dropping,
Stir at -65 to -55 ° C to prepare pentafluorophenyl lithium. A 1 mol / L boron trichloride hexane solution (7.45 ml, 7.45 mmol) was added to the prepared solution of pentafluorophenyllithium at -65 to -55 ° C, and the mixture was stirred at the same temperature for 30 minutes and then heated to room temperature. The solution of the obtained lithium tetrakis (pentafluorophenyl) borate is supplied with ¹⁹ F-N
The yield determined by MR using pentafluorotoluene as an internal standard was 92.3%.

Example 5 A 50 ml glass dropping funnel, a temperature resistor and a septum rubber were attached to a 100 ml glass three-necked flask, and the system was sufficiently purged with nitrogen. In a flask 12.3 wt% butyllithium hexane solution 12.3
g (29.8 mmol) and potassium tert-butoxide 3.3 g (2
9.8 mmol) and 15 ml of diethyl ether.
Cool to ° C. Then, 5 g (29.8 mmol) of pentafluorobenzene and diethyl ether 15
Add dropwise while keeping the internal temperature not exceeding -55 ° C.
After completion of the dropwise addition, the mixture is stirred at -65 to -55 ° C to prepare pentafluorophenyllithium. The prepared solution of pentafluorophenyllithium was added to a solution of methyl iodide in tetrahydrofuran at −55 to −65 ° C., and the mixture was stirred at the same temperature for 30 minutes, then gradually heated to room temperature, and pentafluorotoluene was quantified by gas chromatography. %Met.

Example 6 A 100 ml glass three-necked flask was equipped with a 50 ml glass dropping funnel, a temperature resistor and a septum rubber, and the system was sufficiently purged with nitrogen. 5 g (29.8 mmol) of pentafluorobenzene and 30 ml of diethyl ether are charged into the flask, and the solution is cooled to -65 ° C.
Thereafter, 15.9 g (29.8 mmol) of a 15.0 wt% butyl sodium hexane solution charged in the dropping funnel was heated to an internal temperature of −55 ° C.
And do not exceed After dropping, −65
Stir at ~ -55 ° C to prepare sodium pentafluorophenyl. The prepared solution of sodium pentafluorophenyl was added to a solution of methyl iodide in tetrahydrofuran at -55.
After adding at -65 ° C and stirring at the same temperature for 30 minutes, the temperature was gradually raised to room temperature, and pentafluorotoluene was determined by gas chromatography to be 93.2%.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI C07C 63/70 C07C 63/70 (72) Inventor Kenji Ishimaru 1-1-1 Miya-no-mae, Shinnanyo-shi, Yamaguchi Prefecture Isshin-ryo (56) References JP-A-6-247979 (JP, A) Patent 2790606 (JP, B2) (58) Fields investigated (Int. Cl. ⁶ , DB name) C07F 1/00 C07F 1/02 C07F 1/04 C07C 17 / 00 C07C 25/13 C07C 63/70 CA (STN) REGISTRY (STN)

Claims (1)

(57) [Claims] 1. An equivalent of pentafluorobenzene represented by the following formula [I] C ₆ HF ₅ [I]:
0.5 to 1.5 equivalents of the general formula [II] RM [II] (wherein M represents an alkali metal ion, R represents a hydrocarbon group having 1 to 10 carbon atoms, and the hydrocarbon group has an influence on the reaction. The organic metal compound represented by the formula (1) may be contained in a chain ether solvent, a hydrocarbon solvent or a mixed solvent of a chain ether solvent and a hydrocarbon solvent at -120 ° C. by reacting at to 80 ° C., (wherein, M represents an alkali metal ion.) following general formula _{[III] C 6 F 5 M} [III] to generate pentafluorophenyl alkali metal salt represented by Production method.