Synthesis method of 2-methyl-3-isopropyl phenol
The invention realizes efficient synthesis of 2-methyl-3-isopropylphenol by protecting the phenolic hydroxyl group of 3-bromo-2-methylphenol, performing Suzuki reaction and hydrogenation reaction, thereby solving the problem of lack of synthesis methods in the prior art and being suitable for industrial production.
Patent Information
- Application Number
- CN202510790547.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-13
- Publication Date
- 2025-09-16
AI Technical Summary
Currently, there is no reported method for synthesizing 2-methyl-3-isopropylphenol, which limits its application in the fields of medicine and pesticides.
A three-step reaction route was adopted: first, the phenolic hydroxyl group of 3-bromo-2-methylphenol was protected, then a Suzuki reaction with isopropenylboronic acid naphthalene ester was carried out under a palladium catalyst to generate intermediate C, and finally the protecting group was removed by hydrogenation reaction under a hydrogen environment to generate an isopropyl group to obtain the target product.
The reaction is simple, the post-treatment is convenient, the yield is high, and the method is suitable for industrial production, thereby expanding the application scope of 2-methyl-3-isopropylphenol.
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Figure CN120647510A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the technical field of organic synthesis, and more specifically, to a method for synthesizing 2-methyl-3-isopropylphenol. Background Art
[0002] 2-Methyl-3-isopropylphenol is an organic compound and a phenol derivative. It not only has good antibacterial and anti-inflammatory activity, antioxidant and antiviral potential, but can also be used as a pharmaceutical intermediate for the synthesis of antiviral and antibacterial drugs. Therefore, it has important application value in the fields of medicine and pesticides.
[0003] Because 2-methyl-3-isopropylphenol is widely used, its synthesis and industrial production have always been the focus of people's research. However, there is no synthetic method reported for 2-methyl-3-isopropylphenol, which limits its scope of application to a certain extent.
[0004] Therefore, there is a strong need for a synthetic method of 2-methyl-3-isopropylphenol. Summary of the Invention
[0005] In order to expand the application scope of 2-methyl-3-isopropylphenol, the present application provides a method for synthesizing 2-methyl-3-isopropylphenol.
[0006] The present application provides a method for synthesizing 2-methyl-3-isopropylphenol, which adopts the following technical solution: A synthetic method for 2-methyl-3-isopropylphenol, the synthetic route is as follows: R is an acyl protecting group or a benzyl protecting group; The synthetic method of the above-mentioned 2-methyl-3-isopropylphenol comprises the following steps: (1): Prepared by protecting the phenolic hydroxyl group in 3-bromo-2-methylphenol with a protecting group; (2): After mixing intermediate B, palladium catalyst, isopropenyl boric acid naphthalene ester, a second base catalyst, and a polar solvent, a Suzuki reaction is carried out under a nitrogen environment to obtain intermediate C; (3): After mixing intermediate C, palladium carbon and protic solvent, hydrogenation reaction is carried out in a hydrogen environment to obtain the target product D.
[0007] Preferably, the synthesis method of the 2-methyl-3-isopropylphenol, the synthesis route is as follows: The synthetic method of the above-mentioned 2-methyl-3-isopropylphenol comprises the following steps: (1): Prepared by protecting the phenolic hydroxyl group in 3-bromo-2-methylphenol with a benzyl protecting group; The benzyl protecting group is 4-methoxybenzyl chloride or 4-methoxybenzyl bromide; (2): After mixing intermediate B, palladium catalyst, isopropenyl boric acid naphthalene ester, a second base catalyst, and a polar solvent, a Suzuki reaction is carried out under a nitrogen environment to obtain intermediate C; (3): After mixing intermediate C, palladium carbon and protic solvent, hydrogenation reaction is carried out in a hydrogen environment to obtain the target product D.
[0008] Preferably, the synthesis method of 2-methyl-3-isopropylphenol comprises the following steps: (1): 3-bromo-2-methylphenol, a first base catalyst, a benzyl protecting group, and an aprotic polar solvent are mixed and stirred at 50-100° C. for 0.5-8 hours to obtain a reaction solution; the reaction solution is extracted and separated, and the organic phase is collected and concentrated to obtain intermediate B; (2): After mixing intermediate B, palladium catalyst, isopropenyl boric acid naphthalene ester, second base catalyst, and polar solvent, stirring and reacting at 60-110° C. in a nitrogen environment for 1-8 hours to obtain a reaction liquid; filtering the reaction liquid, collecting the filtrate, and concentrating to obtain intermediate C; (3): After mixing intermediate C, palladium carbon, and a protic solvent, the mixture is stirred in a hydrogen environment at 20-60°C for 2-8 hours to obtain a reaction solution; the reaction solution is filtered, the filtrate is collected, and concentrated to obtain the target product D.
[0009] Preferably, in step (1), the first base catalyst is potassium carbonate or cesium carbonate.
[0010] Preferably, in step (1), the molar ratio of 3-bromo-2-methylphenol, the first base catalyst, and the benzyl protecting group is 1:(1-3):(1-3).
[0011] Preferably, in step (2), the palladium catalyst is [1,1'-bis(di-tert-butylphosphino)ferrocene]dichloropalladium(II) or tetrakistriphenylphosphine palladium.
[0012] Preferably, in step (2), the molar ratio of intermediate B, palladium catalyst, isopropenyl boric acid naphthalene ester, and the second base catalyst is 1:(0.01-0.2):(1-3):(1-3).
[0013] Preferably, in step (3), the molar ratio of intermediate C to palladium carbon is 1:(0.1-0.5).
[0014] In summary, this application has the following beneficial effects: The method of the present application comprises three steps: first, protecting the phenolic hydroxyl group of the raw material 3-bromo-2-methylphenol by various protection methods, such as acetyl and p-methoxybenzyl bromide; second, a borate ester reaction, preferably isopropenyl boric acid naphthalene ester with good activity, is generated as an intermediate with an isopropenyl group; and finally, removing the p-methoxybenzyl group by hydrogenation, while simultaneously hydrogenating the allyl group to generate an isopropyl group as the final product. The three-step reaction process of the present application is simple, convenient in post-processing, high in yield, easy to operate, suitable for scale-up production, and has good industrial application value. BRIEF DESCRIPTION OF THE DRAWINGS
[0015] Figure 1 It is Page 1 in the LCMS chart of intermediate B in Example 1 of the present application; Figure 2 It is Page 2 in the LCMS chart of intermediate B in Example 1 of the present application; Figure 3 It is Page 3 in the LCMS chart of intermediate B in Example 1 of the present application; Figure 4 It is Page 1 in the LCMS chart of Intermediate C in Example 1 of the present application; Figure 5 It is Page 2 in the LCMS chart of intermediate C in Example 1 of the present application; Figure 6 is the HPLC chart of 2-methyl-3-isopropylphenol in Example 1 of the present application; Figure 7 is the HNMR spectrum of 2-methyl-3-isopropylphenol in Example 1 of the present application; Figure 8 is the HNMR diagram of intermediate B in Comparative Example 1 of the present application; Figure 9 This is the LCMS chart of the reaction solution prepared by method 1 in Comparative Example 1 of the present application; Figure 10 This is Page 1 in the LCMS chart of the reaction solution prepared by Method 2 in Comparative Example 1 of the present application; Figure 11 It is Page 2 in the LCMS chart of the reaction solution prepared by Method 2 in Comparative Example 1 of the present application; Figure 12 It is Page 3 in the LCMS chart of the reaction solution prepared by Method 2 in Comparative Example 1 of the present application; Figure 13 This is the LCMS chart of the reaction solution prepared by method 1 in Comparative Example 2 of the present application; Figure 14 This is the LCMS chart of the reaction solution prepared by method 2 in Comparative Example 2 of this application; Figure 15This is the HNMR diagram of the white product in Comparative Example 3 of the present application. DETAILED DESCRIPTION
[0016] The present application is further described in detail below with reference to the accompanying drawings and examples. Example
[0017] Example 1 A synthetic method for 2-methyl-3-isopropylphenol, the synthetic route is as follows:
[0018] The synthetic method of the above-mentioned 2-methyl-3-isopropylphenol comprises the following steps: (1) Preparation of intermediate B: S1: To a 1000 mL three-necked flask, 3-bromo-2-methylphenol (30 g, 160.397 mmol), potassium carbonate (44.34 g, 320.794 mmol), 4-methoxybenzyl chloride (27.63 g, 176.437 mmol), and N,N-dimethylformamide (300 mL) were added to obtain a mixed solution; the mixed solution was stirred at room temperature (20-25°C) for 24 h to obtain an orange-brown suspension.
[0019] The orange-brown suspension was detected by the first LCMS, which showed that 3-bromo-2-methylphenol remained. The orange-brown suspension was heated at 70° C. for 2 h. The second LCMS detection showed that the reaction of 3-bromo-2-methylphenol was complete, obtaining a reaction solution, specifically a brown suspension.
[0020] S2: First, water (700 mL) and ethyl acetate (700 mL) were added to the reaction solution for the first extraction, separated, and the aqueous phase and the organic phase were collected separately; the collected aqueous phase was then extracted with ethyl acetate (500 mL) for a second time, separated, and the organic phase was collected; finally, the organic phase collected from the first extraction was combined with the organic phase collected from the second extraction, first washed three times with water (500 mL), separated, and the collected organic phases were combined again, dried over anhydrous sodium sulfate, and concentrated under reduced pressure to remove residual solvent and water to obtain an orange solid crude product (40 g).
[0021] The crude product was purified by column chromatography (eluent consisting of a mixture of petroleum ether and ethyl acetate in a volume ratio of 20:1) to give a white solid (38 g).
[0022] Reference Figure 1-3 After testing, the white solid was intermediate B with a purity of 98% and a yield of 75.58%. The nuclear magnetic shift data were: 1HNMR (400MHz, DMSO) δ7.39 (d, J = 8.7 Hz, 2H), 7.21–7.03 (m, 2H), 6.96 (d, J = 8.7 Hz, 1H), 5.05 (s, 1H), 3.76 (s, 2H), 2.25 (s, 1H).
[0023] (2) Preparation of intermediate C: S3: To a 2000 mL three-necked flask, intermediate B (48.5 g, 157.884 mmol), [1,1'-bis(di-tert-butylphosphino)ferrocene]dichloropalladium(II) (10.32 g, 15.788 mmol), isopropenylboronic acid naphthalene (47 g, 279.695 mmol), potassium carbonate (54.55 g, 394.711 mmol), water (100 mL), and dioxane (480 mL) were added to obtain a mixed solution; after replacing nitrogen with the mixed solution, the mixture was refluxed with stirring at 100 ° C for 2 h to obtain a reaction solution, specifically a black suspension.
[0024] S4: The reaction solution was sent to LCMS to detect that the reaction of intermediate B was complete, and then filtered through celite. The filtrate was collected and concentrated under reduced pressure to remove the residual solvent and water to obtain a black solid crude product (80 g).
[0025] The crude black solid was purified by column chromatography (eluent: pure petroleum ether) to obtain a black solid product (34 g).
[0026] Reference Figure 4-5 After testing, the black solid was intermediate C with a purity of 93% and a yield of 74.63%. The nuclear magnetic shift data were: 1 HNMR (400MHz, DMSO) δ7.40(d,J=8.5Hz,2H),7.09(d,J=7.9Hz,1H),6.95(t,J=7.4Hz,3H),6.70( d,J=7.5Hz,1H),5.20(s,1H),5.02(s,2H),4.77(s,1H),3.76(s,3H),2.11(s,3H),1.98(s,3H).
[0027] (3) Preparation of target product D: S5: To a 2000 mL flask were added intermediate C (34 g, 126.697 mmol), palladium carbon (3.4 g, 31.949 mmol), and methanol (350 mL) to obtain a mixed solution. After replacing hydrogen with the mixed solution, the mixture was stirred at 20° C. for 8 h to obtain a reaction solution.
[0028] In the embodiments of the present application, palladium carbon is 10% Pd and contains 40-60% water.
[0029] S6: The reaction solution was sent to LCMS for detection, and about 50% of the intermediate C was not de-PMBed. It was then filtered through celite pad, and the filtrate was collected and concentrated under reduced pressure to remove the residual solvent and water to obtain a solid crude product.
[0030] The crude solid product was first purified by column chromatography (eluent: pure petroleum ether) to obtain intermediate C (14 g) without PMB removal, and then purified by column chromatography for the second time (eluent: a mixture of petroleum ether and ethyl acetate in a volume ratio of 9:1) to obtain a crude white solid product (13 g) with an HPLC purity of 91%.
[0031] Petroleum ether (30 mL) was added to the crude white solid product and the mixture was slurried for 5-8 h (5 h in the present embodiment), filtered, and the solid was collected and dried to obtain a white solid product (10.5 g).
[0032] Reference Figure 6-7 After testing, the white solid was 2-methyl-3-isopropylphenol (target product D), with a purity of 96% and a yield of 52.96%. The nuclear magnetic shift data were: 1 HNMR (400MHz, DMSO) δ9.11 (s, 1H), 6.93 (t, J = 7.8Hz, 1H), 6.65 (dd, J = 23.1, 7.8Hz, 2H), 3.14-3.02 (m, 1H), 2.09 (s, 3H), 1.14 (d, J = 6.8Hz, 6H).
[0033] Comparative Example Comparative Example 1 A synthetic method for 2-methyl-3-isopropylphenol, the synthetic route is as follows:
[0034] The synthetic method of the above-mentioned 2-methyl-3-isopropylphenol comprises the following steps: (1) Preparation of intermediate B: S1: 3-bromo-2-methylphenol (12.5 g, 66.832 mmol), pyridine (13.5 mL, 166.915 mmol), and dichloromethane (100 mL, 100.000 mmol) were added to a 1000 mL three-necked flask to obtain a mixed solution; the mixed solution was cooled to 0°C, and the solution was brown-yellow. Then, acetyl chloride (100 mL, 100.000 mmol) was added dropwise to the mixed solution and stirred for 2 h to obtain a reaction solution. At this time, the reaction solution did not heat up significantly, and the brown-yellow solution turned into a yellow suspension.
[0035] S2: The reaction solution was cooled to 0°C and water (125 mL) was added to quench the reaction. The reaction solution showed a temperature increase.
[0036] The reaction solution was separated, and the aqueous phase and the organic phase were collected separately; the collected aqueous phase was extracted twice with dichloromethane (100 mL), separated, and the organic phases extracted twice were collected; the organic phase collected by separation was combined with the organic phases extracted twice, first washed three times with water (150 mL), separated, and the collected organic phases were combined, and then washed three times with 1N HCl (150 mL), separated, and the collected organic phases were combined, and concentrated under reduced pressure to remove residual solvent and water to obtain a brown oily product (15 g).
[0037] After testing, the brown oily product had no UV absorption and no MS. Figure 8 , NMR showed that the brown-yellow oily product was intermediate B.
[0038] (2) Preparation of intermediate C: Method 1: S3: To a 100 mL three-necked flask, intermediate B (1 g, 4.365 mmol), cesium carbonate (3.56 g, 10.914 mmol), isopropylboric acid (0.77 g, 8.731 mmol), [1,1'-bis(di-tert-butylphosphino)ferrocene]dichloropalladium(II) (0.29 g, 0.437 mmol), water (2 mL), and dioxane (10 mL) were added to obtain a mixed solution; after replacing nitrogen with the mixed solution, the mixture was refluxed and stirred at 100 ° C for 24 h to obtain a reaction solution, specifically a black suspension.
[0039] S4: Reference Figure 9 The reaction solution was sent to LCMS for detection, which showed a messy spectrum and no intermediate C, so the next step was not performed.
[0040] Method 2: S5: To a 100 mL three-necked flask were added intermediate B (1 g, 4.365 mmol) and tetrahydrofuran (10 mL) to obtain a mixed solution; the mixed solution was cooled to -78°C, and isopropylmagnesium chloride (2.619 mL, 5.239 mmol) was added dropwise. The mixture was stirred for 3 h to obtain a reaction solution.
[0041] S6: Reference Figure 10-12 The reaction solution was sent to LCMS for detection, which showed that the acetyl group was removed and there was no intermediate C, so the next step was not performed.
[0042] Comparative Example 2 A synthetic method for 2-methyl-3-isopropylphenol, the synthetic route is as follows: The synthetic method of the above-mentioned 2-methyl-3-isopropylphenol comprises the following steps: (1) Preparation of intermediate B: S1: To a 1000 mL three-necked flask, 3-bromo-2-methylphenol (30 g, 160.397 mmol), potassium carbonate (44.34 g, 320.794 mmol), 4-methoxybenzyl chloride (27.63 g, 176.437 mmol), and N,N-dimethylformamide (300 mL) were added to obtain a mixed solution; the mixed solution was stirred at room temperature (20-25°C) for 24 h to obtain an orange-brown suspension.
[0043] The orange-brown suspension was sent to LCMS, which showed that 3-bromo-2-methylphenol remained. The orange-brown suspension was heated at 70° C. for 2 h. LCMS showed that the reaction of 3-bromo-2-methylphenol was complete, to obtain a reaction solution, specifically a brown suspension.
[0044] S2: First, water (700 mL) and ethyl acetate (700 mL) were added to the reaction solution for the first extraction, separated, and the aqueous phase and the organic phase were collected separately; the collected aqueous phase was then extracted with ethyl acetate (500 mL) for a second time, separated, and the organic phase was collected; finally, the organic phase collected from the first extraction was combined with the organic phase collected from the second extraction, first washed three times with water (500 mL), separated, and the collected organic phases were combined again, dried over anhydrous sodium sulfate, and concentrated under reduced pressure to remove residual solvent and water to obtain an orange solid crude product (40 g).
[0045] The crude product was purified by column chromatography (eluent consisting of a mixture of petroleum ether and ethyl acetate in a volume ratio of 20:1) to give a white solid (38 g).
[0046] After testing, the white solid was intermediate B with a purity of 98% and a yield of 75.58%. The nuclear magnetic shift data was: 1 HNMR (400MHz, DMSO) δ7.39 (d, J = 8.7 Hz, 2H), 7.21–7.03 (m, 2H), 6.96 (d, J = 8.7 Hz, 1H), 5.05 (s, 1H), 3.76 (s, 2H), 2.25 (s, 1H).
[0047] (2) Preparation of intermediate C: Method 1: S3: To a 100 mL three-necked flask, intermediate B (1 g, 3.255 mmol), [1,1'-bis(di-tert-butylphosphino)ferrocene]dichloropalladium(II) (0.21 g, 0.326 mmol), isopropylboric acid (0.21 g, 0.326 mmol), cesium carbonate (2.65 g, 8.138 mmol), water (2 mL), and dioxane (10 mL) were added to obtain a mixed solution; after replacing nitrogen with the mixed solution, the mixture was refluxed and stirred at 100 ° C for 2 h to obtain a reaction solution, specifically a brown suspension.
[0048] S4: Reference Figure 13 The reaction solution was sent to LCMS to detect the absence of intermediate C, and the next step was not performed.
[0049] Method 2: S5: To a 100 mL three-necked flask were added intermediate B (1 g, 3.255 mmol) and tetrahydrofuran (10 mL) to obtain a mixed solution; the mixed solution was cooled to -78°C, and isopropylmagnesium chloride (1.628 mL, 3.255 mmol) was then added dropwise. The mixture was stirred for 3 h to obtain a reaction solution.
[0050] S6: Reference Figure 14 The reaction solution was sent to LCMS for detection, which showed that intermediate B had not reacted and there was no intermediate C, so the next step was not performed.
[0051] Comparative Example 3 A synthetic method for 2-methyl-3-isopropylphenol, the synthetic route is as follows: The synthetic method of the above-mentioned 2-methyl-3-isopropylphenol comprises the following steps: (1) Preparation of intermediate B: S1: To a 100 mL three-necked flask, 3-bromo-2-methylanisole (2 g, 9.947 mmol), 1,4-dioxane (20 mL), isopropylboric acid (1.31 g, 14.921 mmol), potassium carbonate (4.12 g, 29.841 mmol), and bis(tri-tert-butylphosphine)palladium(0) (0.25 g, 0.497 mmol) were added to obtain a mixed solution; after replacing nitrogen with the mixed solution, the mixture was refluxed and stirred at 80 ° C for 24 h to obtain a reaction solution, specifically a brown suspension.
[0052] S4: The reaction solution was spotted on a TLC plate (developing solvent consisting of a mixture of ethyl acetate and petroleum ether in a volume ratio of 1:3). The reaction showed that 3-bromo-2-methylanisole had reacted completely. Water (30 mL) was then added to the reaction solution, and the mixture was extracted twice with petroleum ether (20 mL). The liquids were separated, and the organic phase was collected and concentrated under reduced pressure to obtain a white product.
[0053] Reference Figure 15 , after NMR detection, the white product was not intermediate B, and the next step was not carried out.
[0054] By comparing Example 1 with Comparative Examples 1-3, it can be seen that Example 1 of the present application uses 3-bromo-2-methylphenol as a raw material, first protects its phenolic hydroxyl group, and then reacts with active isopropenyl boric acid naphthalene ester to generate an intermediate C with an isopropenyl group, and finally removes the p-methoxybenzyl protecting group by hydrogenation, and simultaneously hydrogenates the allyl group to generate an isopropyl group, thereby finally obtaining 2-methyl-3-isopropylphenol.
[0055] In the examples of the present application, only the reaction raw materials, molar ratio of reaction raw materials, reaction time and reaction temperature in Example 1 are briefly described as an example, but this does not affect the application of the reaction raw materials, molar ratio of reaction raw materials, reaction time and reaction temperature defined in the claims of the present application in this application.
[0056] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make non-creative modifications to the present embodiment as needed, but as long as they are within the scope of the claims of the present application, they are protected by the patent law.
Claims
1. A method for synthesizing 2-methyl-3-isopropylphenol, characterized in that: The synthetic route is as follows: R is an acyl protecting group or a benzyl protecting group; The synthetic method of the above-mentioned 2-methyl-3-isopropylphenol comprises the following steps: (1): Prepared by protecting the phenolic hydroxyl group in 3-bromo-2-methylphenol with a protecting group; (2): After mixing intermediate B, palladium catalyst, isopropenyl boric acid naphthalene ester, a second base catalyst, and a polar solvent, a Suzuki reaction is carried out under a nitrogen environment to obtain intermediate C; (3): After mixing intermediate C, palladium carbon and protic solvent, hydrogenation reaction is carried out in a hydrogen environment to obtain the target product D.
2. The synthetic method of 2-methyl-3-isopropylphenol according to claim 1, wherein The resulting route is as follows: The synthetic method of the above-mentioned 2-methyl-3-isopropylphenol comprises the following steps: (1): Prepared by protecting the phenolic hydroxyl group in 3-bromo-2-methylphenol with a benzyl protecting group; The benzyl protecting group is 4-methoxybenzyl chloride or 4-methoxybenzyl bromide; (2): After mixing intermediate B, palladium catalyst, isopropenyl boric acid naphthalene ester, a second base catalyst, and a polar solvent, a Suzuki reaction is carried out under a nitrogen environment to obtain intermediate C; (3): After mixing intermediate C, palladium carbon and protic solvent, hydrogenation reaction is carried out in a hydrogen environment to obtain the target product D.
3. The synthetic method of 2-methyl-3-isopropylphenol according to claim 2, wherein The following steps are involved: (1): 3-bromo-2-methylphenol, a first base catalyst, a benzyl protecting group, and an aprotic polar solvent are mixed and stirred at 50-100° C. for 0.5-8 hours to obtain a reaction solution; the reaction solution is extracted and separated, and the organic phase is collected and concentrated to obtain intermediate B; (2): After mixing intermediate B, palladium catalyst, isopropenyl boric acid naphthalene ester, second base catalyst, and polar solvent, stirring and reacting at 60-110° C. in a nitrogen environment for 1-8 hours to obtain a reaction liquid; filtering the reaction liquid, collecting the filtrate, and concentrating to obtain intermediate C; (3): After mixing intermediate C, palladium carbon, and a protic solvent, the mixture is stirred in a hydrogen environment at 20-60°C for 2-8 hours to obtain a reaction solution; the reaction solution is filtered, the filtrate is collected, and concentrated to obtain the target product D.
4. The synthetic method of 2-methyl-3-isopropylphenol according to claim 3, wherein In the step (1), the first base catalyst is potassium carbonate or cesium carbonate.
5. The synthetic method of 2-methyl-3-isopropylphenol according to claim 3, wherein In the step (1), the molar ratio of 3-bromo-2-methylphenol, the first base catalyst, and the aromatic benzyl halide is 1:(1-3):(1-3).
6. The method for synthesizing 2-methyl-3-isopropylphenol according to claim 1, wherein In the step (2), the palladium catalyst is [1,1'-bis(di-tert-butylphosphino)ferrocene]dichloropalladium(II) or tetrakistriphenylphosphine palladium.
7. The method for synthesizing 2-methyl-3-isopropylphenol according to claim 1, wherein In the step (2), the molar ratio of intermediate B, palladium catalyst, isopropenyl boric acid naphthalene ester, and the second base catalyst is 1:(0.01-0.2):(1-3):(1-3).
8. The method for synthesizing 2-methyl-3-isopropylphenol according to claim 1, wherein In the step (3), the molar ratio of intermediate C to palladium carbon is 1:(0.1-0.5).