JPH0611717B2 - Method for producing conjugated diene compound - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing a conjugated diene compound. More specifically, it relates to a method for producing a conjugated diene compound from a 1,3-butazinyl metal compound and an organic halide in one step.

The conjugated diene compound is useful as an organic intermediate and a raw material for polymer industry.

[Conventional technology]

Many methods for producing a conjugated diene compound have been reported. For example, a method of partially reducing 1,3-diyne and conjugated enyne, a method of using an acetylene compound, a method of using a vinyl halide, a method of using a Wittig reaction (Sir D. Barton, WDOllis ed., “ COM
PREHENSIVE ORGANIC CHEMISTRY "Pergamon Press Ltd, 197
9), a method using an organic tin compound (Tetrahedron, 1981, 3
967) and the like. However, in the methods known in the prior art, the introduction of diene bond is carried out in multiple stages in each case.
Therefore, it has a drawback that the reaction process becomes long.

[Problems to be solved by the invention]

An object of the present invention is to provide a method for efficiently producing a diene compound by introducing a diene bond, which has been conventionally performed stepwise, in one step.

[Means for solving problems]

The present invention is an efficient method for producing a diene compound in which a 1,3-butadienyl metal compound is used to introduce a diene bond in one step, and the details thereof will be described below.

[Action]

The present invention provides a 1,3-butadienyl metal compound represented by the general formula (1) CH ₂ ═CH CH ═CHM (1) (M is selected from MgX or Li, and X is selected from chlorine, bromine or iodine). And an organic halide represented by the general formula (2) RX (2) (R is selected from a C _{1 to} C ₂₀ alkyl group and an aralkyl group, and X is selected from chlorine, bromine, and iodine) in the presence of a copper catalyst. Lower reaction, general formula
(3) CH ₂ ═CH CH═CHR (3) (R is the same as in (2)) A method for producing a diene compound.

As the 1,3-butadienyl metal compound, for example, 1,3-
Grignard reagents such as butadienyl magnesium chloride, 1,3-butadienyl magnesium bromide, 1,3-butadienyl magnesium iodide or 1,3
-Butadienyl lithium can be mentioned. The Grignard reagent can be prepared by the method developed by the present inventors (Proceedings of the 50th Annual Meeting of the Chemical Society of Japan IV06 (1985)).

The lithium compound includes an organotin compound such as 1-tributylstannyl-1,3-butadiene (49th Annual Meeting of the Chemical Society of Japan 2Z07 (1984)) developed by the present inventors and n-butyllithium, It can be prepared by reacting an alkyllithium such as s-butyllithium or methyllithium with an ether solvent such as ether or THF at a low temperature of -50 to -80 ° C in an inert gas atmosphere.

Examples of organic halides include alkyl halides such as methyl iodide, ethyl iodide, propyl bromide, butyl bromide, butyl iodide, pentyl bromide, hexyl bromide and hexyl iodide, benzyl bromide, benzyl iodide, etc. Aralkyl kill halide.

The copper catalyst may be any monovalent copper compound, such as cuprous iodide and cuprous bromide. Further, in order to increase the solubility of the copper compound, a solubilizing agent such as dimethyl sulfide can be added.

The reaction between the 1,3-butadienyl metal compound and the organic halide is carried out under an inert gas stream such as nitrogen or argon.

As the reaction solvent, a solvent such as diethyl ether, THF, monoglyme, diglyme or the like is used. When a Grignard reagent is used as the 1,3-butadienyl metal compound, the amount of the copper catalyst is 5 to 1 mol of the organic halide.
It is 50 mol%, preferably 10 to 30 mol%.

The amount of Grignard reagent is preferably 1.0 mol or more per mol of the organic halide.

This reaction can be carried out by adding a Grignard reagent to an ether solution containing a copper catalyst and an organic halide. The reaction temperature at the time of addition is preferably -50 to -20 ° C, but it is not necessary to perform any cooling after the addition, and the reaction can be performed at 0 to 25 ° C.

A reaction time of 30 minutes or more is sufficient. When a lithium compound is used as the 1,3-butadienyl metal compound, the reaction proceeds without the copper catalyst, but the presence of the copper catalyst is preferable because the yield is improved.

The amount of copper catalyst is 0.2 to 2.0 mol, preferably 0.5 to 1.5 mol, per mol of the organic halide.

The lithium compound is preferably used in an amount of 1.0 mol or more per mol of the organic halide.

This reaction can be carried out by sequentially adding a lithium compound and an organic halide to an ether solution containing a copper catalyst. The solution temperature at the time of adding the lithium compound is -90.
To -50 ° C, preferably -80 to -60 ° C.

The solution temperature at the time of adding the organic halide is -50 to -20.
C, preferably -40 to -20C.

After completion of the addition, the reaction is completed at 0 to 20 ° C. for 3 to 5 hours.
After reacting for 1 hour, the reaction is preferably performed at 0 to 20 ° C.

Hereinafter, the present invention will be described in more detail with reference to Examples.

〔Example〕

Example 1 30 equipped with reflux condenser, dropping funnel and septum
In a 0 m three-necked flask, scrap metal magnesium 1.50
g and 0.5 g of zinc chloride were added, and the mixture was sufficiently dried by heating under reduced pressure and then replaced with nitrogen. 1,2-dibromoethane 0.5m 0.5
The mTHF solution was added, and then 35 m of THF was added and the mixture was vigorously stirred. After dropping 2.82 g of 1-chloro-1,3-butadiene, ultrasonic treatment was performed for 1.5 hours, and heating under reflux was performed for 1.5 hours. Using 1,10-phenanthroline as an indicator and titration with s-butyl alcohol,
The concentration of this Grignard reagent was 0.545 mol /.

Hexyl iodide (1 g), copper iodide (200 mg) and THF (5 m) were placed in a 50 m three-necked flask equipped with a septum, and the Grignard reagent (10 m) was added at −30 ° C. under a nitrogen stream.
Was dripped. After the completion of dropping, the reaction temperature was set to 0 ° C.,
Stir for hours. Saturated ammonium chloride aqueous solution 15m
Was added to stop the reaction, and the reaction solution was extracted with ether (2 × 30 m). The extract was dried over anhydrous sodium sulfate, and the solvent was distilled off under reduced pressure. The residue was purified by silica gel column chromatography to obtain 279 mg of 1,3-decadiene. The yield was 43%.

Examples 2 and 3 A diene compound was obtained in the same manner as in Example 1 except that the organic halide and the reaction temperature were changed. The results are shown in Table 1.

Example 4 1-tributylstannyl-in a 100 m three-necked flask equipped with a septum, a nitrogen introducing tube and a calcium chloride tube.
3.15 g of 1,3-butadiene and 20 m of THF were added. The reaction solution was cooled to −78 ° C., and 5.4 m (7.12 mmol) of a hexane solution of n-butyllithium was added dropwise under a nitrogen stream. After stirring for 30 minutes, this solution was put into a 100 m three-necked flask and 740 mg of cuprous iodide and 40 m of THF.
Was charged, the system was replaced with nitrogen, and the solution was added dropwise to the solution cooled to -78 ° C. The temperature of the reaction solution was raised to -30 ° C, and a solution of 652 mg of hexyl iodide in 5mTHF was added dropwise. After completion of dropping, the mixture was stirred at -30 ° C for 30 minutes, then the dry eyes acetone bath was removed, and the mixture was stirred for 1 hour. The reaction was stopped by adding 30 m of saturated aqueous ammonia chloride, and ether extraction (2 x 30 m) was performed. The extract was washed with saturated aqueous ammonium chloride solution (2 × 30 m) and saturated sodium hydrogen carbonate solution (2 × 30 m), and dried over anhydrous sodium sulfate.

After the solvent was distilled off, the residue was purified by silica gel column chromatography to obtain 263 mg of 1,3-decadiene. The yield was 62%.

Examples 5 to 6 Diene compounds were obtained in the same manner as in Example 4 except that the organic halide and the reaction time were changed. The results are shown in Table 2.

[Effects of the Invention] As is apparent from the above description, according to the present invention, a diene compound which is conventionally produced in multiple steps and which is important in chemical industry can be efficiently produced in one step.

 ─────────────────────────────────────────────────── --Continued from the front page (56) References JP-A-62-230748 (JP, A) The Journal of Org Chemistry, Vol. 48, No. 48 11 (1983), P. 1912-1914

Claims (1)

[Claims] 1. A butadienyl metal compound represented by the general formula (1) CH ₂ ═CHCH═CHM (1) (M is selected from MgX and Li and X is selected from chlorine, bromine and iodine) and the general formula (2) RX (2) (R is selected from a C _{1 to} C ₂₀ alkyl group and an aralkyl group, and X is selected from chlorine, bromine, and iodine.) RCH = CHCH = CH ₂ (3) (R is selected from a C _{1 to} C ₂₀ alkyl group and an aralkyl group.) A method for producing a diene compound.