JPH06135858A - Production of diene compound - Google Patents

Abstract

PURPOSE:To obtain the subject compound useful as a synthetic raw material for perfumery and diene compound, etc., in high yield without necessitating multi-stage reaction by reacting an alkali metal-substituted olefin with an unsaturated ketone. CONSTITUTION:An alkali metal-substituted olefin of the formula R<1>CH=CMR<2> (R<1> and R<2> are 1-5C alkyl; M is alkali metal) is made to react with an unsaturated ketone of formula I (R<3> to R<5> are 1-5C alkyl) in a solvent (e.g. THF) at a low temperature (-20 to 0 deg.C) and water is dropped to the reaction mixture to hydrolyze the alkali metal salt and obtain a chain diene compound of formula II. A cyclic diene compound of formula III is produced by the dehydrative cyclization of the chain diene compound of formula II. The amount of expensive alkali metal-substituted olefin can be reduced in the production of the objective compound. Arbitrary combination of alkyl groups can be introduced to arbitrary positions.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing an alkyl-substituted diene compound, and more particularly to a chain in which every carbon atom of a non-conjugated pentadiene structure or a cyclopentadiene ring has one alkyl group as a substituent. The present invention relates to a method for producing a diene monool and a cyclic cyclopentadiene, which is industrially advantageous and has a high degree of freedom of a synthesizable diene compound.

[0002]

2. Description of the Related Art Chain-like diene monools in which all carbon atoms of non-conjugated pentadiene have one alkyl group as a substituent, for example, 3,4,5-trimethyl-2, wherein the alkyl group is a methyl group. 5-heptadiene-4-
All is a synthetic fragrance and the later-mentioned 1, 2, 3, 4, 5
-It is useful as a starting material for the synthesis of pentaalkylcyclopentadiene. Further, similarly, cyclopentadiene having an alkyl group in which every carbon atom is one as a substituent, that is, 1,2,3,4,5-pentaalkylcyclopentadiene, is a uniform product for producing a stereoregular polyolefin. It is becoming extremely important as a ligand for metal-based metal complex catalysts. Moreover, for these alkyl-substituted diene compounds, a method for synthesizing a compound in which various alkyl groups are arbitrarily combined and substituted according to the purpose of use is desired.

However, a synthetic method has still been found in which such a diene compound having an alkyl substituent at every carbon atom of the main chain or ring can be easily produced industrially with high yield. Didn't.

When the alkyl group is methyl, 2-bromo-
2-butene was reacted with lithium in diethyl ether to give 2-lithio-2-butene with the by-product of lithium bromide, which was not isolated but reacted as such with ethyl acetate and then with water. 3,4,5-Trimethyl-2,5-
A method for synthesizing heptadien-4-ol is known (RS Threlkel et al .: Organic Synthesis, Vol. 65, 42.
-45 (1987)). In addition, 3, obtained in this way
4,5-Trimethyl-2,5-heptadien-4-ol can be dehydrated and ring-closed in the presence of p-toluenesulfonic acid to synthesize 1,2,3,4,5-pentamethylcyclopentadiene. Can (Orgainc Synthesi
s).

However, according to this method, two molecules of halogenated olefin are required to synthesize one molecule of the diene compound as shown in the following flow chart, and in order to obtain a particularly good yield, , 2-bromo-2
-Requires an olefin bromide such as butene. Also,
It needs two atoms of lithium to match. These olefin bromides and lithium are expensive and resource limited. Therefore, if it is possible to find a synthetic method for reducing the amount of these used, it is extremely advantageous industrially.

[0006]

[Chemical 6]

(Where R ¹ and R ² are as described above,
R ⁶ represents an alkyl group having 1 to 5 carbon atoms, and R ⁷ represents an alkyl group)

Further, according to this method, as is apparent from the flow chart, the chain diene compound has two R ¹ and R ² each as a substituent at symmetrical positions, and at most three kinds of R ¹ and R ² are present. Only alkyl groups can be introduced. In order to introduce an alkyl group in a combination other than that, it is necessary to use a combination of two kinds of halogenated olefins, which is extremely disadvantageous from the viewpoint of the yield of a target product and the separation of by-products. Also in the cyclic diene compound, only those having a combination of alkyl groups corresponding to the above chain diene compound can be obtained.

With respect to 1,2,3,4,5-pentamethylcyclopentadiene, in addition to the above synthesis method, 2,3,4,5-tetramethyl-
It is known to synthesize 2-cyclopenten-1-one and then react it with a methylating agent such as methyllithium or methylmagnesium iodide. (1) Condensing 3-pentanone with acetaldehyde,
Then, dehydration ring closure is carried out to tetrahydro-2,3,5,6-tetramethyl-4H-pyran-4-one, which is dehydrated with an acid (FX Kohl et al .: J. Organometal. Ch.
em., 243, 119 (1983)). (2) A method in which α-methylcrotonic acid is esterified with secondary butyl alcohol and then treated with phosphorus pentoxide and methanesulfonic acid (PE Eaton et al .: J. Org. Chem., 38.
Vol. 4071 (1973)).

However, all the methods are complicated and the yields are low. In particular, α-methylcrotonic acid used as a starting material in the method (2) exists naturally but is expensive. Moreover, in all cases, the final stage synthesis of 1,2,3,4,5-pentamethylcyclopentadiene has a remarkably low yield and is not industrially satisfactory.

Further, as another method for synthesizing 1,2,3,4,5-pentamethylcyclopentadiene, 2-
Lithio-2-butene was reacted with 1-methylcrotonaldehyde to give bis (1-methyl-1-propenyl) carbinol, which was oxidized with active manganese dioxide in pentane to give bis (1-methyl-1- Propenyl) ketone, and then cyclized by adding a mixed solution of formic acid and phosphoric acid to give 2,3,4,5-tetramethylcyclo-2
-Penten-1-one was synthesized and further treated with methyllithium to introduce a methyl group at the 1-position to give 1,2,3,4,5-pentamethyl-2-penten-1.
-Ol, and dehydration of this to obtain 1,2,3,4,5-pentamethylcyclopentadiene is known (L. DeVries: J. Org. Chem., 25, 1838 (196).
0)). However, this method has many industrial disadvantages such as an extremely complicated multistep reaction, a low overall yield, and difficulty in handling because methyllithium has an ignitability in the air.

[0012]

The object of the present invention is to
Hydroxy-1,2,3,4,5-pentaalkyl-
An object of the present invention is to provide an industrially advantageous synthetic method of 1,4-pentadiene that does not require multiple steps. Another object of the present invention is to provide an industrially advantageous method of synthesizing 1,2,3,4,5-pentaalkylcyclopentadiene. Still another object of the present invention is to provide a method capable of synthesizing the above-mentioned chain diene and cyclic pentadiene compounds by introducing an arbitrary substituted alkyl group in combination at an arbitrary position.

[0013]

DISCLOSURE OF THE INVENTION The present inventors have conducted extensive research to solve the above-mentioned problems, and as a result, by reacting an alkali metallized olefin with an unsaturated ketone,
The fact that 3-hydroxy-1,2,3,4,5-tetraalkyl-1,4-pentadiene can be easily industrially synthesized directly, and that 1,2,3,4,5 −
The inventors have found that tetraalkylcyclopentadiene can be easily synthesized industrially, and have completed the present invention.

That is, the method for producing a diene compound of the present invention is characterized by the general formula R ¹ CH═CMR ² (wherein R ¹ and R ² each independently represents an alkyl group having 1 to 5 carbon atoms,
M represents an alkali metal atom) and an alkali metallized olefin represented by the general formula

[0015]

[Chemical 7]

## STR1 ## wherein R ³ , R ⁴ and R ⁵ each independently represents an alkyl group having 1 to 5 carbon atoms, and a general formula characterized by reacting with an unsaturated ketone (I)

[0017]

[Chemical 8]

(Wherein R ¹ , R ² , R ³ , R ⁴ and R
⁵ is as described above), and the chain diene compound obtained as described above is further dehydrated and cyclized.

[0019]

[Chemical 9]

(Wherein R ¹ , R ² , R ³ , R ⁴ and R
⁵ is a method for producing a cyclic diene compound represented by the above).

The method for producing the chain and cyclic diene compounds of the present invention is shown in the following flow chart. However, in order to compare with the flow chart of the conventional method, the flow chart is described from the steps of halogenated olefin (represented by olefin bromide) and alkali metal (represented by lithium). The method of the present invention is shown by and.

[0022]

[Chemical 10]

(Wherein R ¹ , R ² , R ³ , R ⁴ and R
⁽⁵ is as described above)

The alkali metallized olefin used in the present invention is represented by the general formula R ¹ CH = CMR ² , wherein R ¹ and R ² may be the same or different, and each of them may be methyl, ethyl or propyl. , Butyl and pentyl, which may be linear or branched, but methyl and ethyl are preferred and methyl is most preferred because of easy availability and versatility. As M,
Lithium, sodium and potassium are exemplified, and lithium is preferable because of its easy synthesis and handling.

Examples of such alkali metallized olefins are 2-lithio-2-butene and 2-lithio-2-.
Pentene, 3-lithio-2-pentene, 2-lithio-2
-Hexene, 3-lithio-2-hexene, 3-lithio-
3-hexene, 2-lithio-2-heptene, 3-lithio-2-heptene, 3-lithio-3-heptene, 4-lithio-3-heptene, 2-lithio-2-octene, 3-lithio-2- Octene, 3-lithio-3-octene, 4-
Lithio-3-octene, 4-lithio-4-octene, 3
-Lithio-3-nonene, 4-lithio-3-nonene, 5-
Lithio-5-decene and 6-lithio-2-dodecene;
And corresponding sodium and potassium olefins, with lithiated olefins being preferred. Of these, 2-lithio-2-butene, 2
-Lithio-2-pentene, 3-lithio-2-pentene and 3-lithio-3-hexene are more preferred, 2-
Lithio-2-butene is most preferred. There are cis type and trans type in such alkali metalized olefins,
Any of them may be used in the present invention, or a mixture of both may be used.

Such an alkali metallized olefin is
It can be synthesized by reacting a corresponding halogenated olefin, for example, olefin chloride, bromide or iodide, with a corresponding alkali metal using ethers as a reaction solvent. As the halogenated olefin, an olefin bromide is preferable from the viewpoint of both reactivity and economy.

As the halogenated olefin, taking olefin bromide as an example, the corresponding internal olefin is reacted with bromine to give dibromoalkane, which is then treated with an alcohol solution of an alkali metal hydroxide such as potassium hydroxide in methanol. By doing so, it can be easily obtained.

Examples of the alkali metal include lithium, sodium and potassium. Lithium is preferable because it has high reactivity. As lithium, lithium pieces, lithium wires, lithium ribbons, lithium powder, etc. may be used, but in order to promote the reaction rapidly at low temperature, lithium suspended in hydrocarbon, for example, 30 wt% dispersion. Is preferably used. The amount of lithium is preferably stoichiometric with respect to the halogenated olefin.

Examples of ethers used include diethyl ether, tetrahydropyran, hexamethylene oxide and mixed solvents thereof. Tetrahydropyran or hexamethylene oxide is preferable because it has low flammability and is industrially easy to handle, and tetrahydropyran is more preferable among them because it is easily available and has a low boiling point and can be easily purified after the reaction.
The amount of such ethers is 1
It is preferable to use 1 mol or more, preferably 2 mol or more with respect to mol. If it is less than 1 mol, the stirring cannot be sufficiently performed, and the reaction does not proceed effectively.

Further, in order to allow this reaction to proceed with good control, it is preferable to use an aliphatic saturated hydrocarbon in combination with the above ethers. This saturated aliphatic hydrocarbon alone cannot induce the reaction between the halogenated olefin and the alkali metal. Such aliphatic saturated hydrocarbons include alkanes such as n-pentane, n-hexane, n-heptane, n-octane and their isomers; and cycloalkanes such as cyclohexane, methylcyclohexane and ethylcyclohexane. , N-hexane is preferred. It is preferable that such an aliphatic saturated hydrocarbon is gradually added to a system of ethers and an alkali metal, and finally 1.5 to 3 times the amount of the ethers is added.

The reaction proceeds at the reflux temperature of the solvent when using, for example, lithium flakes or a lithium wire as the alkali metal, but proceeds at room temperature to a low temperature when using the lithium suspension. In order to proceed the reaction with good control and good yield, it is preferable to carry out the reaction at a low temperature by such a method. For example, the above-mentioned lithium suspension is dispersed in ethers, and while stirring, -30 ° C to 0 ° C.
After cooling, the halogenated olefin or its aliphatic hydrocarbon solution is added dropwise, and the solvent is refluxed by heating as necessary to complete the reaction.

The alkali metallized olefin thus obtained, for example, the lithium olefin, may be directly used in the reaction of the present invention without isolation.

In the present invention, in the reaction of the first step, one molecule of the alkali metallized olefin obtained as described above is reacted with one molecule of the unsaturated ketone to give an alkali metal salt of the chain diene compound (I). , Then react with water,
This is a reaction for synthesizing a chain diene compound (I).

The unsaturated ketone used in the present invention is represented by the following general formula.

[0035]

[Chemical 11]

R ³ , R ⁴ and R ⁵ may be the same or different from each other and include methyl, ethyl, propyl, butyl and pentyl, which may be linear or branched, and are available and available. Methyl and ethyl are preferred, and methyl is most preferred, because they are easy to handle and have a wide range of uses.

Examples of such unsaturated ketones include 3
-Methyl-3-penten-2-one, 3-methyl-3-
Hexen-2-one, 4-methyl-4-hexene-3-
On, 3-methyl-3-hepten-2-one, 4-methyl-4-hepten-3-one, 5-methyl-5-hepten-4-one, 6-methyl-6-hepten-5-one,
3-methyl-3-octen-2-one, 4-methyl-4
-Octen-3-one, 5-methyl-5-octene-4
-One, 6-methyl-6-octen-5-one, 3-methyl-3-nonen-2-one, 4-methyl-4-nonen-3-one, 5-methyl-5-nonen-4-one , 6-
Methyl-6-nonen-5-one, 7-methyl-7-nonen-6-one, 4-methyl-4-decen-3-one, 5
-Methyl-5-decen-4-one, 6-methyl-6-decen-5-one, 7-methyl-7-decen-6-one,
6-methyl-6-dodecen-5-one, 3-ethyl-3
-Penten-2-one, 3-propyl-3-pentene-
2-one, 3-butyl-3-penten-2-one, 3-
Examples include pentyl-3-penten-2-one.

The amount of the unsaturated ketone used is not particularly limited, but a stoichiometric amount or excess amount relative to the alkali metallized olefin is preferable.
The range of 1-2 mol per mol is more preferred.

As the reaction solvent, the ethers used in the synthesis of the alkali metallized olefin, preferably tetrahydropyran and / or hexamethylene oxide, or the mixed solvent of the ethers and the saturated aliphatic hydrocarbon may be used as they are. In order to control the reaction to obtain a good yield, it is preferable to dissolve the unsaturated ketone to be used in the above range of ethers and / or saturated aliphatic hydrocarbons and add dropwise. The reaction proceeds at room temperature or at a low temperature or under heating up to the reflux temperature of the solvent, but in order to control the side reaction and obtain a good yield, it is preferable to carry out the reaction at a low temperature of −20 to 0 ° C. .

Next, the alkali metal salt is hydrolyzed by dropping water. Water is preferably added in the form of an aqueous salt solution, for example a saturated aqueous solution of ammonium chloride. The reaction temperature is arbitrary, but is preferably -20 to 0 ° C.
Is.

After completion of the reaction, the product is separated into two layers when left to stand, and the produced alkali metal compound is transferred to the aqueous layer.
The organic layer is washed, dried and filtered by a conventional method to obtain a solution containing chain diene monool (I). The chain diene monool may be isolated as a purified product by, for example, desolvation under reduced pressure, or may be used as a solution in the next reaction.

In this way, 3-hydroxy-1,
2,3,4,5-Pentaalkyl-1,4-pentadiene can be obtained in good yield. As the alkyl group bonded to each carbon atom of the pentadiene structure, as described above, by arbitrarily selecting R ^{1 to} R ⁵ of the alkali metallized olefin and the unsaturated ketone to be used, any heterogeneous or the same kind can be selected. It can be introduced at any position. As such a chain diene monool, since it is easy to synthesize and has a wide range of uses, 3,4,5-trimethyl-2,5-hexadiene-4- in which R ^{1 to} R ⁵ are all methyl
All is a typical example.

When the target compound is 1,2,3,4,5-pentaalkylcyclopentadiene (II), as the second step, the corresponding 3-form compound produced in the first step is represented by the following formula. The dehydration ring closure of hydroxy-1,2,3,4,5-pentaalkyl-1,4-pentadiene (I) is performed.

The reaction can be carried out in the presence of an inorganic acid such as sulfuric acid or phosphoric acid; or an organic acid such as p-toluenesulfonic acid or methanesulfonic acid. From the viewpoint of reactivity, p-toluenesulfonic acid is preferred. . The amount of the acid added may be in the range of 0.05 to 0.5 mol with respect to 1 mol of the chain diene compound. As the reaction solvent, the solvent used in the synthesis of the alkali metallized olefin is used as in the first step, but the reaction solvent is not particularly limited thereto, and a general organic solvent can also be used.

The reaction proceeds at room temperature, but when the reaction is started, a violent exotherm is generated, so that the solvent is refluxed. This is preferably continued to be heated to the reflux temperature, and then, after cooling to room temperature, neutralization, washing, drying and distilling off the solvent by normal pressure by a conventional method, and further by a method such as vacuum distillation, the target product is obtained. The cyclic diene compound (II) can be obtained.

Thus, the cyclic diene compound 1,2,3,4,5-penta was obtained in a yield of about 60% of the theoretical amount based on the halogenated olefin used for the synthesis of the raw material alkali metal olefin. Alkylcyclopentadiene can be obtained. As the alkyl group of the pentaalkylcyclopentadiene, as described above, by arbitrarily selecting R ^{1 to} R ⁵ of the alkali metallized olefin and the unsaturated ketone to be used, any different kind or the same kind can be used. Can be introduced to. A typical example of such a pentaalkylcyclopentadiene is 1,2,3,4,5-pentamethylcyclopentadiene because it is easy to synthesize and has a wide range of applications.

[0047]

INDUSTRIAL APPLICABILITY According to the present invention, the amount of alkali metal olefin, which is an expensive raw material, such as lithiated olefin used is reduced as compared with the known method, and it is industrially advantageous and the yield is 3-hydroxy-1,2- 3,4,5-pentaalkyl-1,4-pentadiene and 1,2,3,4,5
It is possible to synthesize pentaalkylcyclopentadiene. Moreover, any alkyl group can be introduced at any position by the method of the present invention.

Of the above-mentioned objects obtained in the present invention, the former is useful both as a synthetic perfume and a raw material of the latter, and the latter is a raw material of an olefin polymerization catalyst, and the industrial value of the present invention is great.

[0049]

EXAMPLES The present invention will be described below with reference to examples. In the examples, all parts are parts by weight. The invention is not limited by these examples.

Example 1 A reaction vessel equipped with a stirrer, a heating / cooling jacket, a nitrogen inlet, a dropping funnel, a reflux condenser and a thermometer was charged with 722 parts of tetrahydropyran and cooled to -10 ° C.
While stirring, 200 parts of a 30 wt% dispersion of lithium (suspended in mineral oil) was added and uniformly dispersed. Separately, 547 parts of 2-bromo-2-butene was taken and dissolved in 1,080 parts of n-hexane. This solution was added dropwise to the above-mentioned lithium-containing dispersion liquid whose temperature was kept at -15 to -5 ° C over about 3 hours while stirring.

Next, while maintaining the system at -10 ° C and stirring, a solution consisting of 399 parts of 3-methyl-3-penten-2-one and 581 parts of n-hexane was added dropwise over about 1 hour. Since the reaction proceeds with exothermic heat with dropping, the reaction temperature is controlled by cooling and adjusting the dropping amount.
The temperature was maintained so as not to exceed 10 ° C. After the dropping, return to room temperature and continue stirring for 1 hour, then -1 again.
After cooling to 0 ° C. and stirring, 2,665 parts of a saturated aqueous solution of ammonium chloride was added dropwise over 1 hour. In this case as well, heat is generated, so the reaction temperature was controlled in the same manner as above.

When the reaction product was allowed to stand, it was separated into an organic layer and an aqueous layer. The layers were separated, the aqueous layer was extracted with n-hexane, added to the organic phase, the organic layer was washed with water, dried over anhydrous sodium sulfate, and filtered. The reaction product thus obtained was purified by column chromatography to give a colorless oil. This oil is 3,4,5-trimethyl-2,5 by GC, TLC, IR and NMR.
-Heptadien-4-ol was confirmed. The yield was 56% based on the theoretical amount based on 2-bromobutene-2 used. IR absorption (neat): 3490, 3290, 2930, 2870, 1455, 138
0, 1100 cm ^{-1 1} H-NMR: δ = 1.38 (s), 1.43 (s), 1.49 (s), 1.61 ~ 1.6
5 (m), 1.70 (s) …… Methyl group proton 5.32 (J = 7.3, q), 5.61 (J = 6.9, q) …… Vinyl group proton

Example 2 Using the same apparatus, starting materials and method as in Example 1,
Lithiation of 2-bromobutene-2, 3-methyl-3-
A solution 3,7 containing 5,4,5-trimethyl-2,5-heptadien-4-ol as a reaction product is obtained by reacting with penten-2-one and hydrolyzing a lithium salt.
50 parts were obtained.

To this solution, 88 parts of p-toluenesulfonic acid monohydrate was added and stirred for 1 hour. Then cooled to room temperature, washed with a saturated aqueous solution of sodium bicarbonate, then with water, then dried over anhydrous sodium sulfate,
Filtered. The solvent was distilled off from the filtrate, and a pale yellow oily substance 1,
500 parts were obtained.

This is subjected to vacuum distillation to give a boiling point of 61 ° C./1
356 parts of a colorless oil of 5 Torr were recovered. This oil was analyzed by GC, TLC and IR to give 1,2,3,4,5-
It was confirmed to be pentamethylcyclopentadiene. The yield was 60% based on the theoretical amount based on 2-bromo-2-butene used.

Example 3 In the same manner as in Example 2 except that 800 parts of hexamethylene oxide was used in place of tetrahydropyran,
2,3,4,5-Pentamethylcyclopentadiene was synthesized. As a result, 350 parts of a colorless oily substance having a boiling point of 61 ° C./15 Torr was recovered and confirmed to be 1,2,3,4,5-pentamethylcyclopentadiene by the same identification method as in Example 2. The yield was 59% with respect to the theoretical amount based on the 2-bromo-2-butene used.

Claims (2)

[Claims] 1. An alkali represented by the general formula R ¹ CH═CMR ² (wherein R ¹ and R ² each independently represent an alkyl group having 1 to 5 carbon atoms, and M represents an alkali metal atom). The metallized olefin is represented by the general formula: (Wherein R ³ , R ⁴ and R ⁵ each independently represent an alkyl group having 1 to 5 carbon atoms), and an unsaturated ketone represented by the formula (I) [Chemical 2] (In the formula, R ¹ , R ² , R ³ , R ⁴ and R ⁵ are as described above), and a method for producing the chain diene compound. 2. An alkali represented by the general formula R ¹ CH═CMR ² (wherein R ¹ and R ² independently represent an alkyl group having 1 to 5 carbon atoms, and M represents an alkali metal atom). The metallized olefin is represented by the general formula: (Wherein R ³ , R ⁴ and R ⁵ each independently represents an alkyl group having 1 to 5 carbon atoms) and reacted with an unsaturated ketone represented by the general formula (I) (Wherein R ¹ , R ² , R ³ , R ⁴ and R ⁵ are as described above), and the compound is represented by the general formula (II): Chemical 5] (Wherein R ¹ , R ² , R ³ , R ⁴ and R ⁵ are as described above), and a method for producing the cyclic diene compound.