JPH06247975A - Production of alkali metallic salt of fluorophenyl ether using pentafluorobenzene in chain ethereal solvent - Google Patents

Abstract

PURPOSE:To obtain the subject metallic salt which is an excellent reactional agent useful as a cocatalyst, etc., from an inexpensive raw material in high yield by reacting a specific pentafluorobenzene with an organic alkali metallic compound using a chain ethereal solvent, etc. CONSTITUTION:One equiv. pentafluorobenzene expressed by the formula C6HF5 is made to react with 0.5-1.5 equiv. organometallic compound expressed by the formula RM (R is 1-10C hydrocarbon; M is alkali metallic ion) (preferably 0.8-1.20 equiv. isopropyl-lithium) in a chain ethereal solvent (e.g. diethyl ether or dipropyl ether) and/or a hydrocarbon-based solvent (e.g. pentane or benzene) at -120 to +80 deg.C (preferably -80 to 0 deg.C) for 5-120min to afford the objective metallic salt.

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 a pentafluorophenyl alkali metal salt 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 be a boron derivative extremely useful as a cocatalyst for cationic complex polymerization, such as tris (pentafluorophenyl). It is used as an important reactant when producing a boron or tetrakis (pentafluorophenyl) borate derivative.

[0002]

BACKGROUND OF THE INVENTION Pentafluorophenyl alkali metal salts are reacted with a boron compound such as boron chloride to give a boron derivative extremely useful as a catalyst component in a polymerization reaction, such as tris (pentafluoro). It is used as an important reaction reagent for introducing a pentafluorophenyl group into boron when producing (phenyl) boron. (For example, Synthesis of Fluoroorg
anic Compounds, p. 190, Springer-Verlag (1985))

To date, several pentafluorophenyl alkali metal salt synthesis reactions are known. For example, a method of producing pentafluorophenyllithium by carrying out a bromine-metal exchange reaction using relatively expensive pentafluorobromobenzene and butyllithium as starting materials for a source of pentafluorophenyl group is already known. For example, Synthesis of Fluoroorganic Compounds, p.190,
Springer-Verlag (1985) prepared lithium pentafluorophenylsulfenate in 94% yield by preparing pentafluorophenyllithium in diethyl ether-hexane at -70 ° C and reacting it with sulfur dioxide.

Also known is a method in which pentafluorobenzene is used as a starting material for a source of a pentafluorophenyl group and butyllithium is used to carry out a hydrogen-metal exchange reaction to produce pentafluorophenyllithium. For example, in J. Org. Chem., 2385, 29 (1964), by reacting pentafluorophenyllithium prepared from pentafluorobenzene and butyllithium with carbon dioxide, the reaction yield is unknown but the reaction solvent system Thus, pentafluorobenzoic acid was obtained in a yield of 68% with a diethyl ether-hexane system, 80.9% with a diethyl ether system, and 82% with a diethyl ether-tetrahydrofuran system. Also, in J. Org. Chem., 4229, 31 (1966), pentafluorophenyllithium prepared from pentafluorobenzene and butyllithium was reacted with hexafluoroacetone to give a yield of 79% as a purification yield, although the reaction yield was unknown. Undecafluoro-2-phenyl-2-propanol is obtained at a rate.

Pentafluorobromobenzene has higher reactivity with organometallic compounds such as butyllithium than pentafluorobenzene. When a hydrogen-metal exchange reaction is performed using butyl lithium to produce pentafluorophenyl lithium, the reaction takes about 5 minutes in a chain ether solvent such as diethyl ether and a cyclic ether solvent such as tetrahydrofuran. When completed, pentafluorophenyllithium is produced almost quantitatively. However, since pentafluorobromobenzene is obtained by brominating pentafluorobenzene, the price is high. That is, it is industrially desirable to use pentafluorobenzene, which is cheaper.

However, since the reactivity of pentafluorobenzene is lower than that of pentafluorobromobenzene, when the deprotonation reaction is carried out using butyllithium to produce pentafluorophenyllithium, it is better than that in a chain ether solvent. In addition, the yield can be improved by adding a cyclic ether solvent such as tetrahydrofuran to a chain ether solvent J. Org. Chem., 2835, 2
9 (1964).

It is generally 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 traded commercially as solutions of saturated hydrocarbon solvents such as hexane, cyclohexane, pentane and the like. Therefore, when pentafluorophenyllithium is produced in a chain ether solvent using a commercially available butyllithium solution of a saturated hydrocarbon solvent such as hexane, a diluted solvent of butyllithium is used. Since the saturated hydrocarbon solvent is mixed in the reaction system, a chain ether solvent-
It becomes a mixed solvent of hydrocarbon solvents, and the reaction becomes more difficult to occur. (For example, J. Org. Chem., 2385, 29 (196
Four))

On the other hand, in the case of producing a compound having a very strong Lewis acidity, such as tris (pentafluorophenyl) boron, if a cyclic ether solvent is present in the reaction system, a strong coordination force causes a cyclic ether to form in the product. In many cases, a coordinated complex is formed and removal becomes difficult.

[0009]

SUMMARY OF THE INVENTION In view of the above situation, the present inventors have used pentafluorobenzene as a starting material for a source of pentafluorophenyl group and used a reaction solvent system which does not use a cyclic ether solvent such as tetrahydrofuran. In the above, various methods for producing a pentafluorophenyl alkali metal salt with high reproducibility and high yield were studied, and as a result, the present invention was achieved.

That is, the gist of the present invention is to add 0.5 to 1.5 equivalents of the organometallic compound represented by the formula [II] to 1 equivalent of the pentafluorobenzene represented by the formula [I] in a chain ether. -120 in a system solvent, a hydrocarbon solvent or a mixed solvent of a chain ether solvent and a hydrocarbon solvent
The present invention relates to a method for producing a pentafluorophenyl alkali metal salt represented by the formula [III] by reacting at a temperature of 80 ° C to 80 ° C.

[0011]

The present invention will be described in detail below. The chain ether solvent referred to in the present invention means 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 referred to in the present invention includes tetrahydrofuran, tetrahydropyran, 1,4-dioxane and the like.

The hydrocarbon solvent used in the present invention is pentane, isopentane, hexane, cyclohexane, heptane, octane, nonane, decane, undecane, dodecane, tridecane, tetradecane, pentadecane, hexadecane, n-paraffin or petroleum ether. Saturated hydrocarbons 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] referred to in the present invention, the functional groups which do not influence the reaction include methyl group, ethyl group,
Propyl group, isopropyl group, propenyl group, 2-isopropenyl group, allyl group, butyl group, sec-butyl group,
tert-butyl group, isobutyl group, pentyl group, sec-pentyl group, tert-pentyl group, neo-pentyl group, isopentyl group, hexyl group, sec-hexyl group, isohexyl group, sec-isohexyl group, cyclohexyl group, phenyl group , 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] are methyllithium, ethyllithium, propyllithium, anisine group, p-anis group and trimethylsilylmethyl group.
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 trilyl lithium, p-tolyl lithium, trimethylsilyl lithium, phenyl sodium, o-tolyl sodium, m-tolyl sodium, p-tolyl sodium, butyl lithium / potassium tert-butoxide, butyl lithium / sodium tert-butoxide, etc., preferably , Basic isopropyl lithium, sec−
Butyl lithium, tert-butyl lithium, sec-pentyl lithium, tert-pentyl lithium, sec-isopentyl lithium, sec-hexyl lithium, cyclohexyl lithium, butyl lithium / potassium tert-butoxide or butyl lithium / sodium tert-butoxide. .

A specific manufacturing method will be described below in sequence. In a solution prepared by dissolving 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, 0.5 to 1.5 equivalents of pentafluorobenzene are added 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 pentafluorophenyl represented by the formula [I] is generated. When the amount of the organometallic compound represented by the formula [II] is less than that of benzene, a large amount of unreacted pentafluorobenzene remains, and when used in excess, the pentafluorophenyl metal salt represented by the formula [III] Since there is a risk of halogen-metal exchange reaction with fluorine as well.
It is desirable to use 0.8 to 1.20 equivalents of the organometallic compound represented by the formula [II]. If the reaction temperature is lower than -80 ° C, the reaction proceeds extremely slowly, and if it is higher than 0 ° C, a side reaction proceeds. Becomes extremely fast and the yield becomes very low in any case. Therefore, it is desirable to react in the range of -80 ° C to 0 ° C. The pentafluorophenyl alkali metal salt represented by the formula [III] is prepared by reacting the reaction mixture at the same temperature for 5 to 120 minutes.

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 a pentafluorophenyl alkali metal which is an important reaction agent for producing a compound such as tris (pentafluorophenyl) borane which is a co-catalyst when preparing a cationic complex polymerization catalyst. It is valuable in that it can provide a method for producing a salt in a chain ether solvent at a high yield from inexpensive pentafluorobenzene instead of pentafluorobenzene bromide.

[0018]

The present invention will be described in more detail with reference to the following examples, which are examples for specifically explaining the present invention, and the present invention is not limited in any way by the following examples. is not. The yield of the reaction is determined by gas chromatography to quantify pentafluorotoluene produced by reacting with a large excess of methyl iodide, or to quantify pentafluorotoluene acid produced by blowing carbon dioxide by gas chromatography, or 0.25 equivalent. After reacting with boron trichloride, N, N-dimethylanilinium tetrakis (pentafluorophenyl) borate formed by counter cation exchange with N, N-dimethylanilinium chloride was induced and quantified by ¹⁹ F-NMR. It is the 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 replaced with nitrogen. The flask is charged with 5 g (29.8 mmol) of pentafluorobenzene and 30 ml of diethyl ether, and the solution is cooled to -65 ° C.
Then, 12.3 g (29.8 mmol) of a 15.5 wt% tert-butyllithium pentane solution charged in a dropping funnel was cooled to an internal temperature of −
Add dropwise while keeping the temperature below 55 ° C. After the dropping is completed,
Stir 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
The mixture was added at -65 ° C, stirred at the same temperature for 30 minutes, gradually warmed to room temperature, and pentafluorotoluene was quantified by gas chromatography to find that it was 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 replaced with nitrogen. The flask is charged with 5 g (29.8 mmol) of pentafluorobenzene and 30 ml of diethyl ether, and the solution is cooled to -65 ° C.
Then, 14.2 g (34.3 mmol) of a 15.5 wt% sec-butyllithium hexane solution charged in the dropping funnel was heated to an internal temperature of −
Add dropwise while keeping the temperature below 55 ° C. After the dropping is completed,
Stir at -65 to -55 ° C to prepare pentafluorophenyllithium. 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 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 replaced with nitrogen. The flask is charged with 5 g (29.8 mmol) of pentafluorobenzene and 30 ml of diethyl ether, and the solution is cooled to -65 ° C.
Then, 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 keeping the temperature below 55 ° C. After the dropping is completed,
Stir at -65 to -55 ° C to prepare pentafluorophenyllithium. 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 thoroughly replaced with nitrogen. The flask is charged with 5 g (29.8 mmol) of pentafluorobenzene and 30 ml of diethyl ether, and the solution is cooled to -65 ° C.
Thereafter, 12.3 g (29.8 mmol) of a 16.1 wt% tert-butyllithium pentane solution charged in the dropping funnel was cooled to an internal temperature of −
Add dropwise while keeping the temperature below 55 ° C. After the dropping is completed,
Stir at -65 to -55 ° C to prepare pentafluorophenyllithium. To the prepared solution of pentafluorophenyllithium, 1 mol / L hexane solution of boron trichloride (7.45 ml, 7.45 mmol) was added at -65 to -55 ° C, and the mixture was stirred at the same temperature for 30 minutes and then allowed to warm to room temperature. The solution of the obtained lithium tetrakis (pentafluorophenyl) borate was treated with ¹⁹ F-N.
The yield determined by MR with pentafluorotoluene as an internal standard substance was 92.3%.

(Example 5) 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 inside of the system was sufficiently replaced with nitrogen. 15.5 wt% butyllithium in hexane solution 12.3 in flask
g (29.8 mmol) and potassium tert-butoxide 3.3 g (2
9.8 mmol) and 15 ml of diethyl ether, and the solution was -65.
Cool to ° C. After that, 5 g (29.8 mmol) of pentafluorobenzene and diethyl ether 15 charged into the dropping funnel.
Add ml dropwise while keeping the internal temperature below -55 ° C.
After completion of dropping, the mixture is stirred at -65 to -55 ° C to prepare pentafluorophenyllithium. The prepared solution of pentafluorophenyllithium was added to a tetrahydrofuran solution of methyl iodide at −55 to −65 ° C., and the mixture was stirred at the same temperature for 30 minutes, gradually warmed 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 inside of the system was sufficiently replaced with nitrogen. The flask is charged with 5 g (29.8 mmol) of pentafluorobenzene and 30 ml of diethyl ether, and the solution is cooled to -65 ° C.
Then, 15.9 g (29.8 mmol) of a 15.0 wt% butyl sodium solution in a hexane charged into a dropping funnel was heated to an internal temperature of -55 ° C.
Drip while not exceeding. -65 after dropping
Stir at ~ -55 ° C to prepare pentafluorophenyl sodium. The prepared solution of sodium pentafluorophenyl was added to a solution of methyl iodide in tetrahydrofuran at -55.
The mixture was added at ~ -65 ° C, stirred at the same temperature for 30 minutes, gradually warmed to room temperature, and pentafluorotoluene was determined by gas chromatography to be 93.2%.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Reference number within the agency FI Technical indication location C07C 63/70 8930-4H (72) Inventor Eiichi Kaji 1-chome 31, Shinnanyo-shi, Yamaguchi Prefecture 31 No. 1 Shin-dormitory (72) Inventor Kenji Ishimaru 1-chome 1-1-1, Miyanoma, Shinnanyo-shi, Yamaguchi Isshin Dormitory

Claims (1)

[Claims] 1. With respect to 1 equivalent of pentafluorobenzene represented by the following formula [I] C ₆ HF ₅ [I],
0.5 to 1.5 equivalents of 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 affects 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 ~ 80 ° C, a pentafluorophenyl alkali metal salt represented by the following general formula [III] C ₆ F ₅ M [III] (wherein M represents an alkali metal ion) is generated. Production method.