JP2022071252A - Method for producing tertiary alcohol having 2,3-dialkyl aromatic group - Google Patents

Abstract

To provide a method for inexpensively producing a tertiary alcohol having a 2,3-dialkyl aromatic group.SOLUTION: In a method for producing a tertiary alcohol represented by general formula (3), a Grignard reagent is synthesized by making a chlorine-containing aromatic compound and magnesium react with each other in the presence of 0.1-2.0 equivalent of lithium chloride with respect to the chlorine-containing aromatic compound. After making the Grignard reagent and a ketone compound react with each other at 15-40°C, the synthesis is conducted by hydrolysis treatment using an aqueous solution including an acid with pKa of 2 or more (each of R1, R2, R3 and R4 indicates an alkyl group).SELECTED DRAWING: None

Description

The present invention relates to an industrially superior method for producing a tertiary alcohol having a 2,3-dialkyl aromatic.

Tertiary alcohols having 2,3-dialkyl aromatics are compounds useful as raw materials for pharmaceutical raw materials, paint raw materials, optical materials and the like. For example, the structure of medetomidine, which is one of the adrenergic agonists, has an aromatic ring having a 2,3-dimethyl group, and its raw material requires a tertiary alcohol having a 2,3-dimethyl aromatic group. Yes (see Patent Document 1).

An example of synthesizing a Grignard reagent using 3-bromo-o-xylene as a starting material and reacting the synthesized Grignard reagent with acetone as a method for producing a tertiary alcohol useful as a raw material for pharmaceuticals and paints. Has been reported. However, since an expensive bromine raw material is generally used for this production method, it has been difficult to supply a tertiary alcohol at a low cost.

In addition, the tertiary alcohol generally produced easily undergoes a dehydration reaction, and 2,3-dimethyl-α-methylstyrene is produced. This compound is a polymerizable compound and can be easily polymerized to become polystyrene. From this, the tertiary alcohol having a 2,3-dialkyl aromaticity obtained by the reaction must suppress the dehydration reaction.
From these facts, an inexpensive method for producing a tertiary alcohol having a 2,3-dialkyl aromaticity has been desired.

Japanese Unexamined Patent Publication No. 2018-505179

An object of the present invention is to provide a method for producing a tertiary alcohol having a 2,3-dialkyl aromaticity, which can be industrially produced by using an inexpensive raw material.

（式中、Ｒ^１、Ｒ^２はアルキル基を示す）
で示される塩素含有芳香族化合物とマグネシウムを、前記塩素含有芳香族化合物に対し０．１～２．０当量の塩化リチウムの存在下で、反応させたグリニャール試薬を合成し、該グリニャール試薬と下記一般式（２）

（式中、Ｒ^３、Ｒ^４はアルキル基を示す）
で示されるケトン化合物を１５～４０℃で反応させた後、ｐＫａが２以上の酸を含む水溶液を用いて加水分解処理して合成する下記一般式（３）

（式中、Ｒ^１、Ｒ^２、Ｒ^３、Ｒ^４はアルキル基を示す）
で示される２，３－ジアルキル芳香族を有する第３級アルコールの製造方法である。 The method for producing a tertiary alcohol having a 2,3-dialkyl aromatic according to the present invention is described in the following general formula (1).

(In the formula, R ¹ and R ² indicate an alkyl group)
A Grignard reagent obtained by reacting the chlorine-containing aromatic compound shown in (1) with magnesium in the presence of 0.1 to 2.0 equivalents of lithium chloride with respect to the chlorine-containing aromatic compound was synthesized, and the Grignard reagent and the following were synthesized. General formula (2)

(In the formula, R ³ and R ⁴ indicate an alkyl group)
The following general formula (3) is synthesized by reacting the ketone compound represented by (1) at 15 to 40 ° C. and then hydrolyzing with an aqueous solution containing an acid having pKa of 2 or more.

(In the formula, R ¹ , R ² , R ³ , and R ⁴ indicate an alkyl group)
It is a method for producing a tertiary alcohol having a 2,3-dialkyl aromaticity represented by.

The method for producing a tertiary alcohol having a 2,3-dialkyl aromatic of the present invention uses a chlorine-containing aromatic compound having a chlorine group, which is inexpensive as a raw material, as a starting material, and has a 2,3-dialkyl aromatic. It is possible to industrially and inexpensively produce a tertiary alcohol having the above.

Further, the tertiary alcohols having 2,3-dialkyl fragrances obtained by the present invention can be used as fine chemicals, raw materials for medical and agricultural chemicals, raw materials for resins / plastics, and electronic materials / optical materials.

（式中、Ｒ^１、Ｒ^２はアルキル基を示す）
で示される塩素含有芳香族化合物である。式中Ｒ^１、Ｒ^２は互いに独立したアルキル基であり、好ましくは炭素数１～１０、より好ましくは炭素数１～６、更に好ましくは炭素数１～４のアルキル基である。アルキル基は、直鎖状、分岐状のいずれでもよい。アルキル基として、例えば、メチル基、エチル基、ｎ－プロピル基、ｉｓｏ－プロピル基、ｎ－ブチル基、ｓｅｃ－ブチル基、ｉｓｏ－ブチル基、ｔｅｒｔ－ブチル基などを挙げることができる。アルキル基Ｒ^１とＲ^２は同じでも別々でも構わない。この２，３－ジアルキルクロロ芳香族化合物は立体的に込み合っており、原料入手の容易さからＲ^１，Ｒ^２として、メチル基、エチル基、ｎ－プロピル基が好ましく、Ｒ^１およびＲ^２がメチル基であるとよい。 Hereinafter, the details of the manufacturing method of the present invention will be described.
The method for producing a tertiary alcohol having a 2,3-dialkylaromatic compound of the present invention uses a 2,3-dialkylchloroaromatic compound as a starting material. This 2,3-dialkylchloroaromatic compound is an inexpensive and easily available industrial raw material, and has the following general formula (1).

(In the formula, R ¹ and R ² indicate an alkyl group)
It is a chlorine-containing aromatic compound represented by. In the formula, R ¹ and R ² are alkyl groups independent of each other, preferably an alkyl group having 1 to 10 carbon atoms, more preferably 1 to 6 carbon atoms, and further preferably 1 to 4 carbon atoms. The alkyl group may be linear or branched. Examples of the alkyl group include a methyl group, an ethyl group, an n-propyl group, an iso-propyl group, an n-butyl group, a sec-butyl group, an iso-butyl group, a tert-butyl group and the like. The alkyl groups R ¹ and R ² may be the same or different. This 2,3-dialkylchloroaromatic compound is sterically crowded, and as ^R1 and ^R2 , a methyl group, an ethyl group, and an n-propyl group are preferable, and ^R1 and ^R2 are preferable because of the availability of raw materials. It should be a methyl group.

The starting material 2,3-dialkylchloroaromatic compound and magnesium are reacted in the presence of lithium chloride to synthesize a Grignard reagent. As the magnesium to be used, cutting chips, ribbon-shaped, and powdered metallic magnesium can be used, but cutting chips and powdered metallic magnesium having a large metal surface are preferable. The amount of metallic magnesium used is preferably 1.0 to 3.0 mol times that of the 2,3-dialkylchloroaromatic compound, and if the amount used is large, unreacted metallic magnesium must be decomposed in a subsequent step. , 1.0 to 1.5 mol times, more preferably.

As the reaction solvent, an ether solvent is used, and general ethers having a hydrocarbon group such as diethyl ether, dipropyl ether and dibutyl ether and cyclic ethers such as tetrahydrofuran can be used, but considering the availability of raw materials. Tetrahydrofuran is preferred. The amount of the solvent used needs to be adjusted to the solubility of the Grignard reagent and the slurry concentration, but is preferably 2 to 10 mol times, more preferably 2 to 5 mol times with respect to the 2,3-dialkylchloroaromatic compound.

In the production of Grignard reagents, when a 2,3-dialkylchloroaromatic compound is reacted with metallic magnesium to synthesize a Grignard reagent, the coexistence of lithium chloride improves the yield of the Grignard reagent. The amount of lithium chloride added is 0.1 to 2.0 equivalents, preferably 0.2 to 2.0 equivalents, more preferably 0.2 to 1.0 equivalents with respect to the 2,3-dialkylchloroaromatic compound. Equivalent is good. If the amount of lithium chloride is less than 0.1 equivalent with respect to the 2,3-dialkylchloroaromatic compound, the yield of the Grignard reagent cannot be sufficiently increased. On the other hand, if it is more than 2.0 equivalents, the production cost of the Grignard reagent becomes high, and further, excess lithium chloride is precipitated and the Grignard reagent cannot be stirred.

In the production of Grignard reagent, the reaction temperature for synthesizing the Grignard reagent by reacting the 2,3-dialkylchloroaromatic compound with metallic magnesium is preferably 50 ° C. or higher, and the reaction proceeds reliably at 60 ° C. or higher. The temperature is more preferred. If the reaction temperature is less than 50 ° C., the reaction of the Grignard reagent may not proceed.

At the start of the reaction, it is preferable to add a small amount of iodine, bromine or an inexpensive compound containing these in order to enhance the reactivity. Examples of such compounds are preferably methyl iodide, ethyl iodide, ethyl bromide, 1,2-dibromoethane and the like.

Grignard reagent preparation can be performed by conventional methods. For example, magnesium and a reaction solvent can be charged in a reaction vessel such as a flask, and if necessary, a reaction activator such as iodine can be contained. Then, in order to initiate the Grignard reaction, a compound selected from methyl iodide, ethyl iodide, ethyl bromide and 1,2-dibromoethane can be added. The input amount of these compounds is preferably 0.005 to 0.1 mol times, more preferably 0.01 to 0.05 mol times with respect to magnesium. After the compound is charged, heat generation is generated and the start of the Grignard reaction is confirmed, and then the 2,3-dialkylchloroaromatic compound may be added dropwise. The aging time after the completion of the dropping is preferably 6 hours or more, more preferably 12 hours or more, because it takes time to synthesize the target Grignard reagent. It is preferable to collect a small amount of the reaction solution and confirm the progress of the reaction by gas chromatography. The aging temperature is preferably 50 ° C. or higher, and more preferably 60 ° C. or higher at which the reaction proceeds reliably. If the aging temperature is less than 50 ° C., the reaction of the Grignard reagent may not proceed.

（式中、Ｒ^３、Ｒ^４はアルキル基を示す）
式中、Ｒ^３、Ｒ^４は互いに独立したアルキル基であり、好ましくは炭素数１～１０、より好ましくは炭素数１～６、更に好ましくは炭素数１～４のアルキル基である。アルキル基Ｒ^３、Ｒ^４は、直鎖状、分岐状のいずれでもよい。アルキル基Ｒ^３、Ｒ^４として、例えば、メチル基、エチル基、ｎ－プロピル基、ｉｓｏ－プロピル基、ｎ－ブチル基、ｓｅｃ－ブチル基、ｉｓｏ－ブチル基、ｔｅｒｔ－ブチル基などを挙げることができる。アルキル基Ｒ^３とＲ^４は同じでも別々でも構わない。一般式（２）で示されるケトン化合物として、例えばアセトン、メチルエチルケトン、ジエチルケトン、メチル－ｎ－プロピルケトン、メチル－ｉｓｏ－プロピルケトン、メチル－ｉｓｏ－ブチルケトンなどが挙げられる。一般的に安価で入手可能な、アセトン、エチルメチルケトン、ジエチルケトン、メチル－ｉｓｏ－ブチルケトンがさらに好ましい。 Next, after synthesizing the Grignard reagent, the obtained Grignard reagent is reacted with the ketone compound represented by the following general formula (2).

(In the formula, R ³ and R ⁴ indicate an alkyl group)
In the formula, R ³ and R ⁴ are alkyl groups independent of each other, preferably 1 to 10 carbon atoms, more preferably 1 to 6 carbon atoms, and further preferably 1 to 4 carbon atoms. The alkyl groups R ³ and R ⁴ may be linear or branched. Examples of the alkyl groups R ³ and R ⁴ include methyl group, ethyl group, n-propyl group, iso-propyl group, n-butyl group, sec-butyl group, iso-butyl group, tert-butyl group and the like. Can be done. The alkyl groups R ³ and R ⁴ may be the same or separate. Examples of the ketone compound represented by the general formula (2) include acetone, methyl ethyl ketone, diethyl ketone, methyl-n-propyl ketone, methyl-iso-propyl ketone, and methyl-iso-butyl ketone. Acetone, ethylmethyl ketone, diethyl ketone, and methyl-iso-butyl ketone, which are generally inexpensive and available, are more preferred.

In the reaction between the Grignard reagent and the ketone compound, it is preferable to react at 15 to 40 ° C. If the reaction temperature is less than 15 ° C., the addition reaction does not proceed sufficiently, which is not preferable. Further, if the reaction temperature exceeds 40 ° C., a side reaction proceeds and the yield decreases, which is not preferable. Further, since the reaction is an exothermic reaction, 15 ° C to 35 ° C, which is easy to control the reaction, is more preferable.

After the reaction between the Grignard reagent and the ketone compound, an acidic aqueous solution containing an acid having a pKa of 2 or more and water is added to carry out a hydrolysis treatment. If water is added as it is after the reaction, solvent-insoluble magnesium hydroxide is generated and the inside of the reaction can cannot be stirred. Therefore, it is advisable to add an aqueous solution containing an acid having a pKa of 2 or more. The acid to be added is an acid having a pKa of 2 or more, and for example, carboxylic acid compounds such as formic acid, acetic acid, propionic acid, butanoic acid, 2-methylpropanoic acid, pentanoic acid, 2,2-dimethylpropanoic acid and phenylethaneic acid. It may be chloroacetic acid, fluoroacetic acid, or bromoacetic acid to which a halogen atom is bonded. Further, a phosphoric acid compound such as phosphoric acid, sodium dihydrogen phosphate dihydrate, sodium dihydrogen phosphate, potassium dihydrogen phosphate and dipotassium hydrogen phosphate may be used. The pKa of the acid used is preferably 2 to 7. When the pKa of the acid is less than 2, the produced tertiary alcohol undergoes a dehydration reaction to produce a styrene derivative. This styrene derivative is not preferable because it is easily polymerized with a polymerizable compound to form polystyrene. Further, when the pKa of the acid exceeds 7, the magnesium hydroxide produced by the hydrolysis of the Grignard reagent cannot be neutralized. Formic acid, acetic acid, propionic acid, and sodium dihydrogen phosphate dihydrate, which are cheaper and industrially available, are even more preferred.

The reaction temperature for hydrolysis is preferably 0 to 30 ° C, more preferably 0 to 20 ° C. If the hydrolysis temperature is high, the obtained tertiary alcohol moiety undergoes a dehydration reaction and changes to a highly polymerizable styrene derivative, which is not preferable.

The amount of the acid used in the hydrolysis is preferably 1.0 to 3.0 mol times, more preferably 1.5 to 2.5 mol times, the amount of magnesium of the Grignard reagent. After adding the acidic aqueous solution, it must be confirmed that the pH of the reaction solution is 7 or less, which is neutral to acidic.

If the pH of the reaction solution is less than 2 after hydrolysis, if the purification is continued as it is, a dehydration reaction may occur and the reaction solution may change to a styrene derivative. Therefore, the pH must be changed to 7 or more to neutral or alkaline. Must be. If it is acidic, add an alkaline aqueous solution, preferably an aqueous solution such as sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium hydrogencarbonate, or potassium hydrogencarbonate to change the pH of the aqueous solution from neutral to alkaline at 7 or higher. , It is preferable to wash.

After washing the reaction solution, the solvent is concentrated, the solvent is replaced with a hydrocarbon solvent such as hexane, heptane, octane, etc., and the solvent is cooled and recrystallized to obtain the desired 2,3-dialkyl aromatics. You can get the tertiary alcohol you have.

（式中、Ｒ^１、Ｒ^２、Ｒ^３、Ｒ^４はアルキル基を示す）
で示される。式（３）中、Ｒ^１、Ｒ^２、Ｒ^３、Ｒ^４はアルキル基であり、式（１）中のＲ^１、Ｒ^２、および式（２）中のＲ^３、Ｒ^４と同様である。得られた２，３－ジアルキル芳香族を有する第３級アルコールは、多岐に渡る分野で有用な化合物であることから、効率的よく工業的に安価に製造できることの意義は大きい。 The obtained tertiary alcohol having a 2,3-dialkyl aromatic compound has the following general formula (3).

(In the formula, R ¹ , R ² , R ³ , and R ⁴ indicate an alkyl group)
Indicated by. In formula (3), R ¹ , R ² , R ³ , and R ⁴ are alkyl groups, similar to R ¹ , R ² in formula (1) and R ³ , R ⁴ in formula (2). be. Since the obtained tertiary alcohol having a 2,3-dialkyl aromatic compound is a compound useful in a wide range of fields, it is of great significance that it can be produced efficiently and industrially at low cost.

Hereinafter, the present invention will be specifically described with reference to Examples.
In the examples, the content and purity of the tertiary alcohol having a 2,3-dialkyl aromatic represented by the general formula (3) were analyzed by the following GC (gas chromatography).
<Purity analysis>
Column: DB-5 (0.25 mm x 30 m x 0.25 μm) (manufactured by Agilent J & W)
Carrier gas: Helium inlet temperature: 300 ° C
Detector temperature: 300 ° C
Column temperature: 50 ° C (2minHold) → 10 ° C / min → 300 ° C (3minHold)
Column flow rate: 3.65 mL / min
Purge flow rate: 5.0 min / min
Split ratio: 20
Sample volume: 1 μL
Sample preparation: Weigh 0.5 g of a sample into a 10 mL volumetric flask and measure with acetonitrile.
In addition, commercially available reagents were used as the reagents used in the experiment.

[Example 1]
61.5 g (0.853 mol) of tetrahydrofuran, 5.39 g (0.221 mol) of magnesium, 3.62 g (0.0854 mol) of lithium chloride, 3-chloro added later in a 300 mL flask equipped with agitator and cooler. (0.4 equivalents with respect to the number of moles of -o-xylene) was charged and stirring was started. 0.465 g (0.00427 mol) of ethyl bromide was added thereto. After stirring for a while, heat generation was confirmed, and heat generation of 5 ° C or higher was confirmed. Then, it was heated and 30 g (0.213 mol) of 3-chloro-o-xylene was added dropwise over 2 hours at a reaction temperature of 60 to 65 ° C. After completion of the dropping, 9 g of toluene was added. After completion of the dropping, aging was carried out at 60 to 65 ° C. for 15 hours. After completion of the reaction, the mixture was cooled and analyzed by gas chromatography. As a result, the reaction yield to the Grignard reagent was 94.7%.
Subsequently, the reaction solution was cooled in a water bath, 17.3 g (0.299 mol) of acetone was added dropwise in the reaction temperature range of 20 to 30 ° C., and the mixture was aged at the same temperature for 2 hours.

After completion of the reaction, the reaction solution was cooled to 15 ° C. or lower, a solution obtained by diluting 26.6 g (0.444 mol) of acetic acid with 80 g of water was added dropwise at a temperature not exceeding 20 ° C., and the mixture was stirred as it was for 1 hour. After that, the aqueous layer is discharged, neutralized with an aqueous solution of sodium hydroxide, and after confirming that the pH is neutral to alkaline at 7 or higher, washing with water is performed twice, the solvent is distilled off, and yellow crystals are formed. Obtained. When the crude crystals were analyzed by gas chromatography, the content of the target substance was 25.5 g (0.155 mol) and the yield was 72.7% (relative to 3-chloro-o-xylene). rice field. The ratio of 2,3-dimethyl-α-methylstyrene obtained by dehydrating the target product was 8.5% with respect to the target product.

Then, 25 g of heptane was added and recrystallized, cooled to −10 ° C. or lower, and the crystals were filtered off to obtain 19.1 g of white crystals. As a result of analyzing the collected white crystals by gas chromatography, the purity was 99.7% 2- (2,3-dimethylphenyl) propane-2-ol. The yield was 54.4% (relative to 3-chloro-o-xylene).

[Example 2]
A Grignard reagent synthesis reaction was carried out according to the contents described in Example 1, and then the reaction was carried out with acetone as described in Example 1. Then, the solution was replaced with acetic acid, and a solution obtained by diluting 69.2 g (0.444 mol) of sodium dihydrogen phosphate dihydrate with 100 g of water was added dropwise at a temperature not exceeding 20 ° C., and the mixture was stirred as it was for 1 hour. Then, neutralization, washing with water and distilling off the solvent were carried out under the conditions described in Example 1 to obtain yellow crystals. When the crude crystals were analyzed by gas chromatography, the content of the target substance was 24.2 g (0.147 mol) and the yield was 69.1% (relative to 3-chloro-o-xylene). rice field. The ratio of 2,3-dimethyl-α-methylstyrene obtained by dehydrating the target product was 9.3% with respect to the target product.

Then, 25 g of heptane was added and recrystallized, cooled to −10 ° C. or lower, and the crystals were filtered off to obtain 17.7 g of white crystals. As a result of analyzing the collected white crystals by gas chromatography, the purity was 99.7% 2- (2,3-dimethylphenyl) propane-2-ol. The yield was 50.5% (relative to 3-chloro-o-xylene).

[Comparative Example 1]
The Grignard reagent according to Example 1 was synthesized without adding lithium chloride, and after the reaction with acetone, the operation as described in Example 1 was carried out to obtain yellow crude crystals. When the crude crystals were analyzed by gas chromatography, the content of the target substance was 20.5 g (0.125 mol) and the yield was 58.4% (relative to 3-chloro-o-xylene). rice field. The ratio of 2,3-dimethyl-α-methylstyrene obtained by dehydrating the target product was 8.5% with respect to the target product.

Then, 25 g of heptane was added and recrystallized, cooled to −10 ° C. or lower, and the crystals were filtered off to obtain 14.6 g of white crystals. As a result of analyzing the collected white crystals by gas chromatography, the purity was 99.7% 2- (2,3-dimethylphenyl) propane-2-ol. The yield was 41.7% (relative to 3-chloro-o-xylene).

[Comparative Example 2]
A Grignard reagent was synthesized according to the contents described in Example 1, and a reaction with acetone was carried out. After the reaction, the reaction solution was cooled to 15 ° C. or lower, and 69.2 g (0.444 mol) of a 35% aqueous hydrochloric acid solution was added dropwise in a range not exceeding 20 ° C. Then, the operation was carried out as described in Example 1 to obtain a yellow solution. When the crude crystals were analyzed by gas chromatography, the content of the target substance was 13.5 g (0.0819 mol) and the yield was 38.4% (relative to 3-chloro-o-xylene). rice field. Further, the ratio of 2,3-dimethyl-α-methylstyrene obtained by causing the dehydration reaction of the target product was 68.8% with respect to the target product, and the dehydration reaction was proceeding.
Heptane was added as it was and recrystallization was performed, but the mixture was cooled to -20 ° C, but no crystals could be obtained.

[Comparative Example 3]
A Grignard reagent was synthesized according to the contents described in Example 1, acetone was added dropwise at a reaction temperature of 5 to 10 ° C., and after completion of the addition, aging was carried out at the same temperature for 2 hours. Then, the operation was performed as described in Example 1 to obtain yellow crystals. When the crude crystals were analyzed by gas chromatography, the content of the target substance was 18.0 g (0.0790 mol) and the yield was 51.4% (relative to 3-chloro-o-xylene). rice field. The ratio of 2,3-dimethyl-α-methylstyrene obtained by dehydrating the target product was 8.6% with respect to the target product.

Then, 25 g of heptane was added and recrystallized, cooled to −10 ° C. or lower, and the crystals were filtered off to obtain 13.0 g of white crystals. As a result of analyzing the collected white crystals by gas chromatography, the purity was 99.6% 2- (2,3-dimethylphenyl) propane-2-ol. The yield was 37.0% (relative to 3-chloro-o-xylene).

The results of Examples 1 and 2 and Comparative Examples 1 to 3 are shown in Table 1 below.

In the method for producing a tertiary alcohol having a 2,3-dialkyl aromaticity of the present invention, a Grignard reagent is synthesized in the presence of lithium chloride using an inexpensive chlorinated 2,3-dialkylchloroaromatic as a starting material. Next, it is a production method for synthesizing a target tertiary alcohol by reacting with alkyl ketones at 15 to 40 ° C. and then hydrolyzing with an aqueous solution containing an acid having a pKa2 or higher. The tertiary alcohol having a 2,3-dialkyl aromaticity of the present invention is an industrially excellent production method.

The tertiary alcohols having 2,3-dialkyl aromatics produced by the method for producing a tertiary alcohol having 2,3-dialkyl aromatics of the present invention are fine chemicals, raw materials for medical and agricultural chemicals, raw materials for resins and plastics, and the like. It can be used as an electronic information material, an optical material, and the like.

Claims (3)

The following general formula (1)

(In the formula, R ¹ and R ² indicate an alkyl group)
The chlorine-containing aromatic compound shown in (1) and magnesium are reacted with the chlorine-containing aromatic compound in the presence of 0.1 to 2.0 equivalents of lithium chloride to synthesize a Grignard reagent, and the Grignard reagent and the following general are synthesized. Equation (2)

(In the formula, R ³ and R ⁴ indicate an alkyl group)
The following general formula (3) is synthesized by reacting the ketone compound represented by (1) at 15 to 40 ° C. and then hydrolyzing with an aqueous solution containing an acid having pKa of 2 or more.

(In the formula, R ¹ , R ² , R ³ , and R ⁴ indicate an alkyl group)
A method for producing a tertiary alcohol having a 2,3-dialkyl aromaticity represented by. The method for producing a tertiary alcohol according to claim 1, wherein R ¹ and R ² of the chlorine-containing aromatic compound represented by the general formula (1) are methyl groups. The method for producing a tertiary alcohol according to claim 1 or 2, wherein the acid having a pKa of 2 or more is formic acid, acetic acid, propionic acid or sodium dihydrogen phosphate dihydrate.