A method for palladium-catalyzed olefin migration

Abstract

The present invention belongs to the field of organic synthesis, and particularly relates to a method for palladium-catalyzed olefin migration. The present invention uses terminal olefins as raw materials, palladium trifluoroacetate as a catalyst, 2-diphenylphosphino-biphenyl as a ligand, and trifluoroacetic acid as a hydrogen source, effectively causing the migration of terminal olefins. This method has easily accessible raw materials, mild reaction conditions, and simple operation.

Description

Technical Field

[0001] The present invention belongs to the field of organic synthesis, and particularly relates to a method for palladium-catalyzed olefin migration. Background Art

[0002] As an important structural unit, olefins widely exist in bioactive molecules and material molecules. They can be easily functionalized as starting materials to synthesize various chemical intermediates and functional skeletons. The isomerization of olefins and their derivatives is a synthetic method for constructing new olefins by the position migration or cis-trans configuration transformation of carbon-carbon double bonds along the backbone carbon chain, and it plays a crucial role in organic synthesis, the synthesis of daily chemicals, the application of feedstock oil, and the synthesis of natural products.

[0003] Currently, for terminal olefins at the raw material end, they are relatively easy to synthesize, inexpensive, and mostly commercialized. Olefin isomerization reactions can start from ordinary olefins and achieve the efficient synthesis of internal olefin compounds, especially polysubstituted olefins that are difficult to construct by other methods, with high atom economy, through the stereoselective or regioselective regulation of carbon-carbon double bonds. Palladium is one of the most widely studied metals in transition metal catalysis, with diverse catalytic properties and high catalytic activity.

[0004] In 2019, Takai et al. reported a palladium-catalyzed system in which the addition of a catalytic amount of a second metal chloride enables the migration of olefins without a heteroatom as a directing group. In this study, the benzene ring was selected as the terminator of the migration, and the migration efficiency was not affected by heteroatoms. However, this study only demonstrated the operational feasibility of double bond migration without the assistance of heteroatom-containing functional groups. The current research on long-distance double bond migration is still imperfect.

[0005]

[0006] Regarding how to improve the regioselectivity and stereoselectivity of the palladium-catalyzed long-distance double bond migration reaction of olefins to obtain the target product with almost a single configuration is still a major problem. Summary of the Invention

[0007] The object of the present invention is to provide a method for palladium-catalyzed olefin migration. Using palladium trifluoroacetate Pd(TFA) 2 as a catalyst, a terminal olefin compound as a substrate, and trifluoroacetic acid as a hydrogen source to perform terminal olefin isomerization.

[0008] The method for synthesizing the olefin shown in Formula II provided by the present invention includes the following steps:

[0009] In an inert atmosphere, the olefin shown in Formula I, 2-diphenylphosphino-biphenyl, palladium trifluoroacetate, and trifluoroacetic acid are reacted in dichloroethane / or dichloromethane, and after the reaction is completed, the olefin shown in Formula II is obtained through purification;

[0010]

[0011] In the formulas I and II, n is an integer greater than or equal to 1; R is an aryl group, and the aryl group may contain different halogen atoms or groups.

[0012] Furthermore, in the formulas I and II, n is an integer less than or equal to 18.

[0013] Furthermore, the molar dosage of palladium trifluoroacetate fed is 0.0475 - 0.0525 times, preferably 0.05 times, the molar dosage of the olefin shown in formula I fed.

[0014] Furthermore, the molar dosage of 2 - diphenylphosphino - biphenyl fed is 0.19 - 0.21 times, preferably 0.2 times, the molar dosage of the olefin shown in formula I fed.

[0015] Furthermore, the molar dosage of trifluoroacetic acid fed is 0.285 - 0.315 times, preferably 0.3 times, the molar dosage of the olefin shown in formula I fed.

[0016] Furthermore, the concentration of the olefin shown in formula I in the mixed solution composed of 2 - diphenylphosphino - biphenyl, palladium trifluoroacetate, trifluoroacetic acid and dichloroethane is 1.7 moles per liter.

[0017] Furthermore, the reaction temperature of the reaction is 45 - 55 °C, and the reaction time is 23 - 25 hours; preferably, the reaction temperature is 50 °C and the reaction time is 24 hours.

[0018] Furthermore, the purification is column chromatography purification, the column - packing solvent is petroleum ether; the eluent is petroleum ether; the filler of the column used is silica gel with 300 - 400 mesh, and the specification is diameter 3 cm × height 20 cm.

[0019] Specifically, the compound shown in formula II is any one of the following compounds:

[0020]

[0021] The present invention uses olefins with different structures as raw materials, palladium trifluoroacetate as a catalyst, 2 - diphenylphosphino - biphenyl as a ligand, and trifluoroacetic acid as a hydrogen source, effectively causing the migration of terminal olefins. This method has easily - obtained raw materials, mild reaction conditions and simple operation. Specific Embodiments

[0022] The present invention will be further described below in conjunction with specific embodiments, but the present invention is not limited to the following embodiments. The methods are all conventional methods unless otherwise specified. The raw materials can all be obtained from public commercial channels unless otherwise specified.

[0023] In the column chromatography step of the following examples, the packing material of the chromatography column used is silica gel with a mesh size of 300-400, and the specification is a diameter of 3 cm × a height of 20 cm.

[0024] First, a list analysis and comparison of the screening of each detailed reaction condition is carried out:

[0025] Table 1. Condition screening. a

[0026]

[0027] a 1a (0.50 mmol), Pd source (0.05 mmol) [Pd 2 (dba) 3 (0.025 mmol)], monophosphine ligand (0.10 mmol), diphosphine ligand (0.05 mmol) and TFA (0.30 mmol) were added to the reaction flask, and the solvent 1,2-dichloroethane (DCE) was added, and the mixture was stirred at room temperature for 24 hours. b The determination of the conversion rate was based on the NMR of the crude reaction solution (BnOMe was added as an internal standard to the crude reaction solution), and was jointly determined in combination with the spectral diagram of the separated pure compound. The ratio of 2a / 3a was also determined from the NMR data of the crude product. c toluene. d THF. e DCM. f DMF. g dioxane.

[0028]

[0029] It can be seen from the data in the table that different phosphine ligands have a very large impact on the reaction. For example, triphenylphosphine, tris(4-chlorophenyl)phosphine, and tris(2-methoxy)phosphine, the reaction activities of most diphosphine ligands are very low or even non-existent. The biphenyl-based phosphine ligands have good reaction activities. Among them, the conversion rate and yield of L1 (the ratio of the total amount of olefins obtained by purification to the theoretical yield) are very high and the proportion of the main product is relatively large. Only the trans-olefin product is formed in this reaction, with single selectivity.

[0030] Through the screening of the Pd source, it is found that most Pd catalysts have reaction activities. Pd(OAc) 2 、Pd 2 (dba) 3 and Pd(TFA) 2 all gave good conversion rates and yields, but Pd(OAc) 2 and Pd 2 (dba) 3There are relatively more by-products, so Pd(TFA) was finally selected. 2 as the best palladium source.

[0031] The comparative experiments of solvents showed that both 1,2-dichloroethane (DCE) and dichloromethane (DCM) gave relatively high conversion rates and yields. However, considering their volatile chemical properties and the harm to human health, we still chose 1,2-dichloroethane (DCE) as the reaction solvent.

[0032] In the following examples, different structurally olefins were used as raw materials (the molar dosage of the feed was 0.50 mmol), palladium trifluoroacetate was used as the catalyst, 2-diphenylphosphino-biphenyl was used as the ligand, and trifluoroacetic acid was used as the hydrogen source to investigate the universality of the substrate range of this isomerization catalytic system, as follows:

[0033] Example 1. Olefin (see Structural Formula II-a):

[0034] Synthesis reaction equation of the raw material 5-phenyl-1-pentene of Formula I-a:

[0035]

[0036] Ethyl bromobenzene 1 (15.0 g, 81.0 mmol) and tetrahydrofuran (30 mL) were successively added to the reactor, and a magnetic stir bar was placed. The reflux device was assembled and connected to a constant pressure dropping funnel, and all were sealed with rubber stoppers. The air in the system was evacuated and replaced with Ar gas three times. During evacuation, it was heated with a hot air blower, and finally an Ar balloon was inserted. Allylmagnesium bromide 2 (97 ml, 97.0 mmol) was slowly added through the constant pressure dropping funnel, and the temperature was raised to 85 °C and heated under reflux overnight. 200 g of ice water was added to the reaction solution to quench the reaction, and it was extracted with ethyl acetate (3 x 80.0 mL). The organic phase was washed with saturated brine, dried over anhydrous sodium sulfate, filtered and concentrated by rotary evaporation, and then purified by column chromatography to obtain 10.06 g of the colorless liquid product shown in Formula I-a, with a yield of 85%.

[0037] The results of structural confirmation are as follows: 1 HNMR (400 MHz, CDCl 3 ) δ 7.31 - 7.27 (m, 2H), 7.26 - 7.17 (m, 3H), 5.90 - 5.80 (m, 1H), 5.06 - 4.97 (m, 2H), 2.63 (t, J = 7.6 Hz, 2H), 2.14 - 2.08 (m, 2H), 1.77 - 1.69 (m, 2H); 13 CNMR (100 MHz, CDCl 3 ) δ 142.6, 138.7, 128.6, 128.4, 125.8, 114.9, 35.5, 33.4, 30.8.

[0038]

[0039] Pd(TFA) 2 (0.0083 g, 0.025 mmol), 2-diphenylphosphino-biphenyl (0.0338 g, 0.1 mmol) and TFA (0.0175 g, 0.15 mmol) were added to a reaction vessel, 0.3 mL of dichloroethane, 5-phenyl-1-pentene I-a (0.0731 g, 0.50 mmol) were added, Ar was charged, and the reaction was carried out at 50 °C for 24 h. Column chromatography, specific conditions: column was packed with petroleum ether, eluent was petroleum ether, and colorless liquid II-a (0.0637 g, 87% yield) was obtained.

[0040] The results of structure confirmation are as follows: 1 HNMR (400 MHz, CDCl 3 ) δ 7.38 - 7.33 (m, 2H), 7.32 - 7.27 (m, 2H), 7.19 (tt, J = 6.4, 1.2 Hz, 1H), 6.39 (dt, J = 16.0, 1.6 Hz, 1H), 6.23 (dt, J = 15.6, 6.8 Hz, 1H), 2.20 (qd, J = 7.2, 1.2 Hz, 2H), 1.56 - 1.45 (m, 2H), 0.96 (t, J = 7.6 Hz, 3H); 13 CNMR (100 MHz, CDCl 3 ) δ 138.1, 131.1, 130.0, 128.6, 126.9, 126.0, 35.3, 22.7, 13.9.

[0041] The synthesized compound was identified by structure as the target compound olefin II-a.

[0042] Example 2. Olefin (see structural formula II-b):

[0043] Synthesis reaction equation of raw material 5-(4-fluorophenyl)-1-pentene I-b:

[0044]

[0045] 4-Fluorophenethyl bromide 3 (2.0000 g, 9.84 mmol) and the second organic solvent tetrahydrofuran (20 mL) were successively added to the reactor. The reactor was placed in a stirrer at 0 °C, and allylmagnesium bromide 2 (12.7 mL, 12.79 mmol) was slowly added. After the addition was complete, the temperature was slowly raised to 85 °C and the reaction was refluxed overnight. Water was added to the reaction solution to quench the reaction, and the mixture was extracted with ethyl acetate (3 x 30.0 mL). The organic phase was washed with saturated brine, dried over anhydrous sodium sulfate, filtered, and the filtrate was concentrated by rotary evaporation. Column chromatography was performed to obtain 0.662 g of the product shown in I-b as a colorless liquid, with a yield of 41%.

[0046] The structure confirmation results are as follows: 1 HNMR (400 MHz, CDCl 3 ) δ 7.14 - 7.11 (m, 2H), 6.99 - 6.94 (m, 2H), 5.88 - 5.77 (m, 1H), 5.05 - 4.96 (m, 2H), 2.59 (t, J = 7.6 Hz, 2H), 2.08 (q, J = 8 Hz, 3H), 1.73 - 1.66 (m, 2H); 13 CNMR (100 MHz, CDCl 3 ) δ 162.5, 160.1, 138.6, 138.1 (d, J = 13.3 Hz), 129.9 (d, J = 30.0 Hz), 115.2, 115.0, 114.97, 34.6, 33.3, 30.9.

[0047]

[0048] Pd(TFA) 2 (0.0083 g, 0.025 mmol), 2 - diphenylphosphino - biphenyl (0.0338 g, 0.1 mmol) and TFA (0.0175 g, 0.15 mmol) were added to the reaction vessel, 0.3 mL of dichloroethane was added, and 5-(4 - fluorophenyl)-1 - pentene I - b (0.0821 g, 0.50 mmol) was added. The reaction was carried out under Ar at 50 °C for 24 h. Column chromatography was performed. The specific conditions were as follows: the column was filled with petroleum ether, and the eluent was petroleum ether. A colorless liquid II - b (0.0784 g, 95% yield) was obtained.

[0049] The structure confirmation results are as follows: 1 HNMR (400 MHz, CDCl 3)δ 7.33 - 7.27 (m, 2H), 7.02 - 6.94 (m, 2H), 6.34 (d, J = 15.6 Hz, 1H), 6.14 (dt, J = 15.6, 6.8 Hz, 1H), 2.21 - 2.14 (m, 2H), 1.54 - 1.44 (m, 2H), 0.95 (t, J = 7.6 Hz, 3H); 13 C NMR (100 MHz, CDCl 3 )δ 162.0 (d, J = 243.9 Hz), 134.2 (d, J = 3.3 Hz), 130.8 (d, J = 2.2 Hz), 128.8, 127.4 (d, J = 7.8 Hz), 115.4 (d, J = 21.3 Hz), 35.2, 22.7, 13.9.

[0050] The synthesized compound was identified by structure as the target compound olefin II - b.

[0051] Example 3. Olefin (see structural formula II - c):

[0052]

[0053] Pd(TFA) 2 (0.0083 g, 0.025 mmol), 2 - diphenylphosphino - biphenyl (0.0338 g, 0.1 mmol) and TFA (0.0175 g, 0.15 mmol) were added to a reaction vessel, 0.3 mL of dichloroethane was added, 5 - (3 - fluorophenyl) - 1 - pentene I - c (0.0821 g, 0.50 mmol) was added, Ar was filled, and the reaction was carried out at 50 °C for 24 h. Column chromatography, specific conditions: packed column with petroleum ether, eluent was petroleum ether, and colorless liquid II - c (0.0772 g, 94% yield) was obtained.

[0054] The results of structure confirmation are as follows: 1 H NMR (400 MHz, CDCl 3 ) 7.26 - 7.20 (m, 1H), 7.12 - 7.01 (m, 2H), 6.92 - 6.84 (m, 1H), 6.35 (d, J = 16.0 Hz, 1H), 6.24 (dt, J = 15.6, 6.4 Hz, 1H), 2.23 - 2.15 (m, 2H), 1.54 - 1.45 (m, 2H), 0.96 (td, J = 7.2, 1.2 Hz, 3H); 13 C NMR (100 MHz, CDCl 3)δ 163.3 (d, J = 243.1 Hz), 140.5 (d, J = 7.7 Hz), 132.6, 130.0 (d, J = 8.5 Hz), 129.0 (d, J = 2.6 Hz), 121.9 (d, J = 2.6 Hz), 113.6 (d, J = 21.2 Hz), 112.4 (d, J = 21.5 Hz), 35.2, 22.6, 13.9。

[0055] The synthesized compound was identified as the target compound olefin II-c through structural identification.

[0056] Example 4. Olefin (see structural formula II-d):

[0057]

[0058] Pd(TFA) 2 (0.0083 g, 0.025 mmol), 2-diphenylphosphino-biphenyl (0.0338 g, 0.1 mmol) and TFA (0.0175 g, 0.15 mmol) were added to the reaction vessel, 0.3 mL of dichloroethane was added, 6-(4-methoxyphenyl)-1-hexene I-d (0.0951 g, 0.50 mmol), Ar was filled, and the reaction was carried out at 50 °C for 24 h. Column chromatography, specific conditions: column was filled with petroleum ether, eluent was petroleum ether, and colorless liquid II-d (0.0779 g, 82% yield) was obtained.

[0059] The results of structural confirmation are as follows: 1 HNMR (400 MHz, CDCl 3 ) δ 7.29 - 7.25 (m, 2H), 6.86 - 6.80 (m, 2H), 6.32 (dt, J = 15.6, 1.6 Hz, 1H), 6.08 (dt, J = 16.0, 6.8 Hz, 1H), 3.80 (s, 3H), 2.22 - 2.14 (m, 2H), 1.48 - 1.31 (m, 4H), 0.92 (t, J = 7.2 Hz, 3H); 13 C NMR (100 MHz, CDCl 3 ) δ 158.7, 130.9, 129.2, 129.1, 127.1, 114.0, 55.4, 32.8, 31.8, 22.4, 14.1。

[0060] The synthesized compound was identified as the target compound olefin II-d through structural identification.

[0061] Example 5. Olefin (see structural formula II-f):

[0062]

[0063] Pd(TFA) 2 (0.0083 g, 0.025 mmol), 2-diphenylphosphino-biphenyl (0.0338 g, 0.1 mmol) and TFA (0.0175 g, 0.15 mmol) were added to a reaction vessel, 0.3 mL of dichloroethane, 5-(3-methylphenyl)-1-pentene I-f (0.0801 g, 0.50 mmol) were added, Ar was filled, and the reaction was carried out at 50 °C for 24 h. Column chromatography, specific conditions: column was filled with petroleum ether, eluent was petroleum ether, and colorless liquid II-f (0.0708 g, 88% yield) was obtained.

[0064] The results of structure confirmation are as follows: 1 HNMR (400 MHz, CDCl 3 ) δ 7.21 - 7.12 (m, 3H), 7.04 - 6.98 (m, 1H), 6.36 (d, J = 16 Hz, 1H), 6.22 (dt, J = 16.0, 6.8 Hz, 1H), 2.34 (s 3H), 2.23 - 2.14 (m, 2H), 1.54 - 1.44 (m, 2H), 0.96 (t, J = 7.2 Hz, 3H); 13 CNMR (100 MHz, CDCl 3 ) δ 138.1, 138.0, 130.9, 130.1, 128.5, 127.7, 126.8, 123.2, 35.3, 22.7, 21.5, 13.9.

[0065] The synthesized compound was identified as the target compound olefin II-f through structure identification.

[0066] Example 6. Olefin (see structural formula II-g):

[0067] Synthesis reaction equation of raw material 5-(2-chlorophenyl)-1-pentene I-g:

[0068]

[0069] 2-Chloro-phenethyl bromide 4 (1.0000 g, 4.56 mmol) and tetrahydrofuran (10 mL) were successively added to a reactor, the reactor was placed in stirring at 0 °C, allyl magnesium bromide 2 (9.11 mL, 9.11 mmol) was slowly added, and after the addition was completed, the temperature was slowly raised to 85 °C and the reaction was refluxed overnight. Water was added to the reaction solution to quench the reaction, extracted with ethyl acetate (3 x 30.0 mL), the organic phase was washed with saturated brine, dried over anhydrous sodium sulfate, filtered, and the filtrate was rotary evaporated and then column chromatographed to obtain 0.405 g of the product shown as colorless liquid I-g, 49% yield.

[0070] The results of structure confirmation are as follows:1 HNMR (400 MHz, CDCl 3 ) δ 7.33 (dd, J = 7.2, 1.3 Hz, 1H), 7.23 - 7.11 (m, 3H), 5.91 - 5.80 (m, 1H), 5.08 - 4.97 (m, 2H), 2.74 (t, J = 7.7 Hz, 2H), 2.14 (q, J = 7.2 Hz, 2H), 1.76 - 1.69 (m, 2H); 13 CNMR (100 MHz, CDCl 3 ) δ 140.1, 138.6, 134.1, 130.5, 129.6, 127.3, 126.8, 115.0, 33.5, 33.3, 29.0.

[0071]

[0072] Pd(TFA) 2 (0.0083 g, 0.025 mmol), 2 - diphenylphosphino - biphenyl (0.0338 g, 0.1 mmol) and TFA (0.0175 g, 0.15 mmol) were added to a reaction vessel. 0.3 mL of dichloroethane was added, and 5 - (2 - chlorophenyl) - 1 - pentene I - g (0.0903 g, 0.50 mmol) was added. The reaction was purged with Ar and reacted at 50 °C for 24 h. Column chromatography was carried out. The specific conditions were as follows: The column was filled with petroleum ether, and the eluent was petroleum ether, to obtain colorless liquid II - g (0.0840 g, 93% yield).

[0073] The results of structure confirmation are as follows: 1 HNMR (400 MHz, CDCl 3 ) δ 7.51 (dd, J = 7.6, 1.6 Hz, 1H), 7.33 (dd, J = 8.0, 1.6 Hz, 1H), 7.20 - 7.17 (m, 1H), 7.15 - 7.12 (m, 1H), 6.76 (d, J = 16.0 Hz, 1H), 6.22 (dt, J = 16.0, 1.6 Hz, 1H), 2.24 (qd, J = 7.2, 1.6 Hz, 2H), 1.58 - 1.47 (m, 2H), 0.97 (t, J = 7.6 Hz, 3H); 13 CNMR (100 MHz, CDCl 3 ) δ 136.1, 134.0, 130.4, 129.7, 127.9, 126.8, 126.7, 126.3, 35.4, 22.6, 13.9.

[0074] The synthesized compound was identified by structure as the target compound olefin II - g.

[0075] Example 7. Olefin (see Structural Formula II-h):

[0076] Synthesis reaction equation of raw material olefin Formula I-h:

[0077]

[0078] 5 (1.0000 g, 4.40 mmol) and tetrahydrofuran (10 mL) were successively added to the reactor. The reactor was placed in a stirrer at 0 °C, and allylmagnesium bromide 2 (5.7 mL, 5.72 mmol) was slowly added. After the addition was complete, the temperature was slowly raised to 85 °C and the reaction was refluxed overnight. Water was added to the reaction solution to quench the reaction, and the mixture was extracted with ethyl acetate (3 x 30.0 mL). The organic phase was washed with saturated brine, dried over anhydrous sodium sulfate, filtered, and the filtrate was rotary evaporated and then purified by column chromatography to obtain 0.6774 g of the product shown as pale yellow liquid I-h, with a yield of 82%.

[0079] The structure confirmation results are as follows: 1 HNMR (400 MHz, CDCl 3 ) δ 7.01 (s, 1H), 6.91 (d, J = 8.1 Hz, 1H), 6.70 (d, J = 8.1 Hz, 1H), 5.89 - 5.78 (m, 1H), 5.05 - 4.95 (m, 2H), 4.54 (t, J = 8.7 Hz, 2H), 3.18 (t, J = 8.6 Hz, 2H), 2.55 (t, J = 7.6 Hz, 2H), 2.08 (q, J = 7 Hz, 2H), 1.71 - 1.64 (m, 2H); 13 CNMR (100 MHz, CDCl 3 ) δ 158.3, 138.8, 134.6, 127.9, 127.0, 125.0, 114.7, 109.0, 71.2, 34.9, 33.4, 31.3, 30.0。

[0080]

[0081] Pd(TFA) 2 (0.0083 g, 0.025 mmol), 2-diphenylphosphino-biphenyl (0.0338 g, 0.1 mmol) and TFA (0.0175 g, 0.15 mmol) were added to the reaction vessel, 0.3 mL of dichloroethane was added, I-h (0.0941 g, 0.50 mmol), and Ar was filled. The reaction was carried out at 50 °C for 24 h. Column chromatography was performed. The specific conditions were as follows: The column was filled with petroleum ether, and the eluent was petroleum ether to obtain pale yellow liquid II-h (0.0804 g, 85% yield).

[0082] The structure confirmation results are as follows:1 HNMR(400MHz, CDCl 3 ) δ 7.23 (d, J = 2.0 Hz, 1H), 7.08 (dd, J = 8.4, 2.0 Hz, 1H), 6.71 (d, J = 8.4 Hz, 1H), 6.32 (d, J = 16.0 Hz, 1H), 6.05 (dt, J = 15.6, 6.8 Hz, 1H), 4.56 (t, J = 8.8 Hz, 2H), 3.19 (t, J = 8.8 Hz, 2H), 2.19 - 2.12 (m, 2H), 1.53 - 1.42 (m, 2H), 0.95 (t, J = 7.2 Hz, 3H); 13 CNMR(100MHz, CDCl 3 ) δ 159.3, 131.0, 129.7, 128.3, 127.4, 126.2, 122.2, 109.2, 71.4, 35.2, 29.8, 22.9, 13.9。

[0083] The synthesized compound was identified as the target compound olefin II-h through structure determination.

[0084] Example 8. Olefin (see structural formula II-i):

[0085]

[0086] Pd(TFA) 2 (0.0083 g, 0.025 mmol), 2-diphenylphosphino-biphenyl (0.0338 g, 0.1 mmol) and TFA (0.0175 g, 0.15 mmol) were added to a reaction vessel, 0.3 mL of dichloroethane was added, I-i (0.0941 g, 0.50 mmol), Ar was filled, and the reaction was carried out at 50 °C for 24 h. Column chromatography, specific conditions: packed with petroleum ether, eluent was petroleum ether, to obtain II-i as a colorless liquid (0.0867 g, 92% yield).

[0087] The results of structure confirmation are as follows: 1 HNMR(400MHz, CDCl 3 ) δ 7.92 (t, J = 2.0 Hz, 1H), 7.79 - 7.75 (m, 1H), 7.54 (dt, J = 7.6, 1.6 Hz, 1H), 7.38 (t, J = 7.6 Hz, 1H), 6.42 (d, J = 15.6 Hz, 1H), 6.31 (dt, J = 16.0, 6.8 Hz, 1H), 2.61 (s, 3H), 2.25 - 2.17 (m, 2H), 1.55 - 1.46 (m, 2H), 0.96 (t, J = 7.2 Hz, 3H); 13CNMR (100 MHz, CDCl 3 ) δ 198.4, 138.5, 137.4, 132.6, 130.5, 129.1, 128.8, 126.8, 125.7, 35.2, 26.8, 22.5, 13.9.

[0088] The synthesized compound was identified as the target compound olefin II-i by structure elucidation.

[0089] Example 9. Olefin (see structural formula II-j):

[0090]

[0091] Pd(TFA) 2 (0.0083 g, 0.025 mmol), 2-diphenylphosphino-biphenyl (0.0338 g, 0.1 mmol) and TFA (0.0175 g, 0.15 mmol) were added to a reaction vessel, 0.3 mL of dichloroethane was added, 4-(4-methylphenyl)-1-butene I-j (0.0731 g, 0.50 mmol) was added, Ar was charged, and the reaction was carried out at 50 °C for 24 h. Column chromatography, specific conditions: packed with petroleum ether, eluent was petroleum ether, and colorless liquid II-j (0.0688 g, 94% yield) was obtained.

[0092] The results of structure confirmation are as follows: 1 HNMR (400 MHz, CDCl 3 ) δ 7.26 - 7.22 (m, 2H), 7.12 - 7.07 (m, 2H), 6.35 (dt, J = 16.0, 1.6 Hz, 1H), 6.21 (dt, J = 16.0, 6.4 Hz, 1H), 2.32 (s, 3H), 2.27 - 2.16 (m, 2H), 1.09 (t, J = 7.2 Hz, 3H); 13 CNMR (100 MHz, CDCl 3 ) δ 136.5, 135.3, 131.7, 129.3, 128.7, 125.9, 26.2, 21.3, 13.9.

[0093] The synthesized compound was identified as the target compound olefin II-j by structure elucidation.

Claims

1. A method for palladium-catalyzed olefin migration, characterized in that, in an inert atmosphere, an olefin having the structure shown in Formula I, 2-diphenylphosphino-biphenyl, palladium trifluoroacetate, and trifluoroacetic acid are reacted in dichloroethane and / or dichloromethane, and after the reaction is completed, the olefin having the structure shown in Formula II is obtained through purification; ， The compound shown in Formula II is any one of the following compounds: 、 、 、 、 、 、 、 、 。 2. The method for palladium-catalyzed olefin migration according to claim 1, characterized in that, the molar dosage of palladium trifluoroacetate fed is 0.0475 to 0.0525 times the molar dosage of the olefin shown in Formula I.

3. The method for palladium-catalyzed olefin migration according to claim 1, characterized in that, the molar dosage of 2-diphenylphosphino-biphenyl fed is 0.19 to 0.21 times the molar dosage of the olefin shown in Formula I.

4. The method for palladium-catalyzed olefin migration according to claim 1, characterized in that, the molar dosage of trifluoroacetic acid fed is 0.285 to 0.315 times the molar dosage of the olefin shown in Formula I.

5. The method for palladium-catalyzed olefin migration according to claim 1, characterized in that, the reaction time of the reaction is 23 to 25 hours.

6. The method for palladium-catalyzed olefin migration according to claim 1, characterized in that, the purification is column chromatography purification.

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