(E)-1, 4-diether olefin and preparation method thereof

Abstract

The invention discloses (E)-1, 4-diether olefin and a preparation method thereof, and the (E)-1, 4-diether olefin is obtained by using 1, 3-diene as a raw material and carrying out electrochemical reaction in the presence of an electrolyte and a solvent, wherein the 1, 2, 4-trimethyl-1, 3- The structural formula of the 1, 3-diene is as follows: R1 is phenyl, p-fluorophenyl, p-chlorphenyl, p-bromophenyl, p-methylphenyl, p-methoxyphenyl, p-trifluoromethylphenyl, p-trifluoromethoxyphenyl, p-acetoxyphenyl, p-methyl formate phenyl, p-cyanophenyl, p-pinacol borate phenyl, p-phenylphenyl, o-oxybenzyl phenyl and o-methoxyphenyl; r1 is one of 1, 2-naphthyl; the solvent is a mixed solvent containing methanol. The preparation method of (E)-1, 4-diether olefin has high E-selectivity and 1, 4-selectivity, and an electro-catalysis mode is adopted, so that the use of a stoichiometric toxic, expensive or dangerous oxidant is avoided.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of organic synthesis, in particular to a kind of (E)-1,4-diether olefin and preparation method thereof. BACKGROUND

[0002] The selective difunctionalization of 1,3-dienes is a challenging research area that can transform readily available starting materials into highly functionalized useful molecules, providing a direct route to polysubstituted olefins. Molecules containing 1,3-diene backbones are well-known functional acceptors that can be used as very valuable carbon feedstocks for difunctionalization reactions due to their enhanced reactivity compared to simple olefins.

[0003] Direct dioxygenation of olefins has received great attention since the pioneering work of Sharpless. The classical Sharpless asymmetric dihydroxylation reaction requires the use of toxic osmium and oxidizing agents, which has prompted the development of alternative environmentally friendly methods. Most strategies achieve 1,2-selective oxidation through catalyst-controlled processes. Therefore, it is still of great value to develop a more environmentally friendly, more controllable and more practical approach to achieve the high selectivity of alkoxylation of 1,3-diene. SUMMARY

[0004] The technical problem to be solved by the present application is how to prepare (E)-1,4-diether olefin in an environmentally friendly and efficient manner.

[0005] The present application solves the above technical problems by the following technical means:

[0006] A preparation method of (E)-1,4-diether olefin, which uses 1,3-diene as raw material to carry out electrochemical reaction in the presence of electrolyte and solvent to obtain the (E)-1,4-diether olefin; wherein the structural formula of the 1,3-diene is R 1 is one of phenyl, p-fluorophenyl, p-chlorophenyl, p-bromophenyl, p-methylphenyl, p-methoxyphenyl, p-trifluoromethylphenyl, p-trifluoromethoxyphenyl, p-acetoxyphenyl, p-methyl formate phenyl, p-cyanophenyl, p-phenoxyphenyl, p-benzylphenyl, o-methoxyphenyl, 2-naphthyl, and the wavy line in the structural formula represents Z / E isomerization; the solvent is a mixed solvent containing methanol.

[0007] Preferably, in the 1,3-diene, Z / E = 57-80:20-43.

[0008] Preferably, the structural formula of the 1,3-diene is ​ One of them.

[0009] Preferably, the electrochemical reaction uses platinum sheets and graphite as electrodes.

[0010] Preferably, a platinum sheet is used as the anode and graphite as the cathode.

[0011] Preferably, the electrolyte is tetrabutyltetrafluoroborate (tt-butylammonium tetrafluoroborate). n Bu4NBF4), tetrabutylacetic acid ( n Bu4NOAc), Tetrabutylhexafluorophosphate ( n A mixture of one or more of Bu4NPF6.

[0012] Preferably, tetrabutylammonium hexafluorophosphate ( n Bu4NPF6) is an electrolyte.

[0013] Preferably, the solvent is one of the following: a mixed solvent of tetrahydrofuran and methanol, a mixed solvent of toluene and methanol, a mixed solvent of acetonitrile and methanol, or a mixed solvent of dichloroethane and methanol. Methanol serves as both the methoxy source and the co-solvent.

[0014] Preferably, in the mixed solvent of tetrahydrofuran (THF) and methanol (MeOH), the volume ratio of tetrahydrofuran to methanol is 1:1; in the mixed solvent of toluene and methanol, the volume ratio of toluene to methanol is 1:1; in the mixed solvent of acetonitrile and methanol, the volume ratio of acetonitrile to methanol is 1:1; and in the mixed solvent of dichloroethane and methanol, the volume ratio of dichloroethane to methanol is 1:1.

[0015] Preferably, the solvent is a mixture of tetrahydrofuran and methanol in a volume ratio of 1:1.

[0016] Preferably, the current of the electrochemical reaction is 5-15 mA and the time is 1-4 hours.

[0017] Preferably, the reaction is carried out at room temperature.

[0018] Preferably, the ratio of 1,3-diene to solvent is 2 mmol:3 mL; the ratio of electrolyte to solvent is 0.1 mmol:1 mL; and the ratio of 1,3-diene to methanol is 2 mmol:1.5 mL.

[0019] Preferably, the method for preparing the (E)-1,4-diether olefin includes the following steps: mixing 1,3-diene with an electrolyte, adding a solvent, and reacting under electrolysis to obtain the (E)-1,4-diether olefin.

[0020] Preferably, it uses 1,3-diene as a raw material and a mixed solvent of methanol and tetrahydrofuran as a solvent, with methanol serving as both a methoxy source and a co-solvent, and tetrabutylammonium hexafluorophosphate (... n Using Bu4NPF6 as the electrolyte, a platinum sheet as the anode, and graphite as the cathode, the reaction was carried out for 4 hours under a constant current of 10 mA to obtain the (E)-1,4-diether olefin.

[0021] Electrochemical oxidative functionalization has the advantages of being economical and green, and can effectively prepare molecules with diverse functional groups. In the preparation method of this invention, 1,3-diene is used as the raw material, platinum (Pt) is used as the anode, and carbon (C) is used as the cathode. n Bu4NPF6 was used as the electrolyte, and tetrahydrofuran:methanol (volume ratio 1:1) was used as the mixed solvent. The reaction was carried out at room temperature and at a current of 10mA for 4 hours to obtain the (E)-1,4-diether olefin. It can construct functionalized compounds in one step through electrocatalytic 1,3-diene alkoxy reaction, and the electrocatalytic method avoids the use of stoichiometric toxic, expensive or dangerous oxidants.

[0022] Preferably, the method further includes a step of separating and purifying the product after the reaction; the separation and purification method includes at least one of column chromatography, vacuum distillation and recrystallization.

[0023] The compound (E)-1,4-diether olefin prepared in this invention has the following structural formula:

[0024]

[0025] Among them, R 1 It is one of the following: phenyl, p-fluorophenyl, p-chlorophenyl, p-bromophenyl, p-methylphenyl, p-methoxyphenyl, p-trifluoromethylphenyl, p-trifluoromethoxyphenyl, p-acetoxyphenyl, p-methyl p-formate phenyl, p-cyanophenyl, p-pinacol p-borate phenyl, p-phenylenephenyl, o-oxobenzylphenyl, o-methoxyphenyl, 2-naphthyl; R 2 Methyl; R 3 It is either methyl or H.

[0026] The present invention also proposes a (E)-1,4-diether olefin, the structural formula of which is shown in Formula I below:

[0027]

[0028] R 1 It is one of the following: phenyl, p-fluorophenyl, p-chlorophenyl, p-bromophenyl, p-methylphenyl, p-methoxyphenyl, p-trifluoromethylphenyl, p-trifluoromethoxyphenyl, p-acetoxyphenyl, p-methyl p-formate phenyl, p-cyanophenyl, p-pinacol p-borate phenyl, p-phenylenephenyl, o-oxobenzylphenyl, o-methoxyphenyl, 2-naphthyl; R 2 It is a methyl group.

[0029] This invention uses 1,3-diene as a raw material and develops a highly 1,4-selective 1,3-diene dialkoxylation reaction by direct electrolysis in a diaphragm-free electrolytic cell, generating (E)-1,4-diether olefins in very ideal yields.

[0030] The advantages of this invention are:

[0031] (1) The raw materials used in this invention are inexpensive, readily available, and easy to operate;

[0032] (2) The reaction conditions of this invention are mild and simple;

[0033] (3) The present invention can obtain (E)-1,4-diether olefins with high E-selectivity and 1,4-selectivity;

[0034] (4) The synthesis method used in this invention is green and environmentally friendly;

[0035] (5) The yield and selectivity of the method described in this invention can be maintained after scale-up;

[0036] (6) The synthesis method described in this invention has a wide range of applications and can synthesize various substituted diether olefin compounds. Attached Figure Description

[0037] Figure 1 The hydrogen NMR spectrum of the product prepared in Example 2 of this invention;

[0038] Figure 2 The carbon NMR spectrum of the product prepared in Example 2 of this invention;

[0039] Figure 3 The hydrogen NMR spectrum of the product prepared in Example 3 of this invention;

[0040] Figure 4 The carbon NMR spectrum of the product prepared in Example 3 of this invention;

[0041] Figure 5 The NMR fluorine spectrum of the product prepared in Example 3 of this invention;

[0042] Figure 6 The hydrogen NMR spectrum of the product prepared in Example 4 of this invention;

[0043] Figure 7 The carbon NMR spectrum of the product prepared in Example 4 of this invention;

[0044] Figure 8 The hydrogen NMR spectrum of the product prepared in Example 5 of this invention;

[0045] Figure 9The carbon NMR spectrum of the product prepared in Example 5 of this invention;

[0046] Figure 10 The hydrogen NMR spectrum of the product prepared in Example 6 of this invention;

[0047] Figure 11 The carbon NMR spectrum of the product prepared in Example 6 of this invention;

[0048] Figure 12 The hydrogen NMR spectrum of the product prepared in Example 7 of this invention;

[0049] Figure 13 The carbon NMR spectrum of the product prepared in Example 7 of this invention;

[0050] Figure 14 The hydrogen NMR spectrum of the product prepared in Example 8 of this invention;

[0051] Figure 15 The carbon NMR spectrum of the product prepared in Example 8 of this invention;

[0052] Figure 16 The NMR fluorine spectrum of the product prepared in Example 8 of this invention;

[0053] Figure 17 The hydrogen NMR spectrum of the product prepared in Example 9 of this invention;

[0054] Figure 18 The carbon NMR spectrum of the product prepared in Example 9 of this invention;

[0055] Figure 19 The NMR fluorine spectrum of the product prepared in Example 9 of this invention;

[0056] Figure 20 The hydrogen NMR spectrum of the product prepared in Example 10 of this invention;

[0057] Figure 21 The carbon NMR spectrum of the product prepared in Example 10 of this invention;

[0058] Figure 22 The hydrogen NMR spectrum of the product prepared in Example 11 of this invention;

[0059] Figure 23 The image shows the carbon NMR spectrum of the product prepared in Example 11 of this invention. Detailed Implementation

[0060] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0061] Unless otherwise specified, all test materials and reagents used in the following examples are commercially available.

[0062] Unless otherwise specified in the embodiments, the techniques or conditions described in the literature in this field or in accordance with the product manual may be followed.

[0063] Example 1

[0064] Preparation of diene compounds:

[0065] Diene compounds were synthesized according to previously reported methods (Org. Lett., 2013, 15, 6054-6057; Chem. Eur. J., 2012, 18, 2212-2216; Green Chem., 2018, 20, 1213-1217), and the experimental procedures were basically consistent with those reported in the literature; among which... The preparation method includes the following steps:

[0066]

[0067] Allyltriphenylphosphonium bromide (30 mmol) and potassium tert-butoxide (60 mmol) were dissolved in tetrahydrofuran (30 mL) solution and stirred for 30 minutes under an ice-water bath at 0 °C. Then, benzaldehyde (20 mmol) was added, and the mixture was heated to room temperature at 0 °C and reacted for 20 hours. The reaction solution was extracted with ethyl acetate and water, and the resulting organic phase was concentrated under vacuum and separated by column chromatography to obtain the final product in 94% yield.

[0068] The preparation process is as follows:

[0069]

[0070] Specifically, it includes the following steps:

[0071] Ethyltriphenylphosphonium bromide (30 mmol) and potassium tert-butoxide (60 mmol) were dissolved in tetrahydrofuran (30 mL) solution and stirred for 30 minutes under an ice-water bath at 0 °C. Then, cinnamaldehyde (20 mmol) was added, and the mixture was heated to room temperature at 0 °C and reacted for 20 hours. The reaction solution was extracted with ethyl acetate and water, and the resulting organic phase was concentrated under vacuum and separated by column chromatography to obtain the final product in 87% yield.

[0072] The other diene compounds used in this invention were all prepared by the above method. Specifically, benzaldehyde with different functional groups was used to replace benzaldehyde to prepare diene compounds with different functional groups. Specifically, 4-fluorobenzaldehyde, 4-chlorobenzaldehyde, 4-bromobenzaldehyde, 4-methylbenzaldehyde, 4-methoxybenzaldehyde, 4-trifluoromethylbenzaldehyde, 4-trifluoromethoxybenzaldehyde, 4-acetoxybenzaldehyde, 4-methylformate benzaldehyde, 4-cyanobenzaldehyde, 4-pinacolborate benzaldehyde, 4-phenylbenzaldehyde, 2-benzyloxybenzaldehyde, 2-methoxybenzaldehyde, naphthaldehyde, 4-nitrobenzaldehyde, and 4-aminobenzaldehyde were used to replace benzaldehyde to prepare other diene compounds.

[0073] Example 2

[0074] Preparation of (E)-1,4-diether olefins

[0075] Prepared according to the reaction equation shown below:

[0076]

[0077] The Z / E mixed 1,3-diene prepared in Example 1 (Z / E = 59:41) (2 mmol) was placed in a 10 mL reaction tube, and 116 mg was added to the 10 mL reaction tube. n Bu4NPF6 was added to 1.5 mL of tetrahydrofuran solvent and 1.5 mL of methanol solvent. The reaction was carried out at room temperature under a current of 10 mA with Pt sheet as anode and graphite C as cathode for 4 hours. The target product compound was obtained by column chromatography (petroleum ether PE: ethyl acetate EA volume ratio = 30:1) with a yield of 80%.

[0078] The corresponding NMR spectra of the products are as follows: Figure 1 and Figure 2 As shown, the data is as follows: 1 H NMR (600MHz, CDCl3) δ7.36–7.31(m,4H),7.29–7.25(m,1H),5.88–5.76(m,2 H), 4.65 (d, J = 6.0Hz, 1H), 3.93 (d, J = 5.2Hz, 2H), 3.33 (s, 3H), 3.31 (s, 3H). 13C NMR (151MHz, CDCl3) δ141.0,133.7,128.8,128.6,127.8,126.9,83.8,72.5,58.1,56.5.

[0079] Example 3

[0080] Preparation of (E)-1,4-diether olefins

[0081] Prepared according to the reaction equation shown below:

[0082]

[0083] Z / E mixed 1,3-diene (Z / E = 60:40) (2 mmol) was added to a 10 mL reaction tube, and 116 mg was added to the 10 mL reaction tube. n Bu4NPF6 was added, and 1.5 mL of tetrahydrofuran solvent and 1.5 mL of methanol solvent were added. The reaction was carried out at room temperature with a Pt sheet as the anode and a graphite C as the cathode for 4 hours. The target product compound was obtained by column chromatography (petroleum ether PE: ethyl acetate EA volume ratio = 30:1) with a yield of 83%.

[0084] The corresponding NMR spectra of the products are as follows: Figure 3 , Figure 4 and Figure 5 As shown, the data is as follows: 1 H NMR (600MHz, CDCl3) δ7.30–7.27(m,2H),7.05–7.00(m,2H),5.78(td,J=3.2,1 .4Hz,2H),4.63(d,J=4.4Hz,1H),3.94–3.92(m,2H),3.32(s,3H),3.31(s,3H). 13 C NMR (151MHz, CDCl3) δ162.4 (d, J = 247.6Hz), 136.8 (d, J = 3.4Hz), 133.4, 129.0, 128.6 (d, J = 8.2Hz), 115.4 (d, J = 21.4Hz), 83.1, 72.4, 58.2, 56.5. 19 F NMR (377MHz, CDCl3) δ -114.93.

[0085] Example 4

[0086] Preparation of (E)-1,4-diether olefins

[0087] Prepared according to the reaction equation shown below:

[0088]

[0089] Z / E mixed 1,3-diene (Z / E = 77:23) (2 mmol) was added to a 10 mL reaction tube, and 116 mg was added to the 10 mL reaction tube. n Bu4NPF6 was added to 1.5 mL of tetrahydrofuran solvent and 1.5 mL of methanol solvent. The reaction was carried out at room temperature under a current of 10 mA with Pt sheet as anode and graphite C as cathode for 4 hours. The target product compound was obtained by column chromatography (petroleum ether PE: ethyl acetate EA volume ratio = 30:1) with a yield of 86%.

[0090] The corresponding NMR spectra of the products are as follows: Figure 6 and Figure 7 As shown, the data is as follows: 1 H NMR(600MHz, CDCl3) δ7.31(d,J=8.2Hz,2H),7.26(d,J=4.6Hz,2H),5.81–5.7 5(m,2H),4.62(d,J=5.0Hz,1H),3.93(d,J=3.6Hz,2H),3.32(d,J=1.3Hz,6H). 13 C NMR (101MHz, CDCl3) δ139.6,133.5,133.1,129.3,128.8,128.3,83.1,58.2,56.6.

[0091] Example 5

[0092] Preparation of (E)-1,4-diether olefins

[0093] Prepared according to the reaction equation shown below:

[0094]

[0095] Z / E mixed 1,3-diene (Z / E = 60:40) (2 mmol) was added to a 10 mL reaction tube, and 116 mg was added to the 10 mL reaction tube. n Bu4NPF6 was added, and 1.5 mL of tetrahydrofuran solvent and 1.5 mL of methanol solvent were added. The reaction was carried out at room temperature with a Pt sheet as the anode and a graphite C as the cathode for 4 hours. The target product compound was obtained by column chromatography (petroleum ether PE: ethyl acetate EA volume ratio = 30:1) with a yield of 85%.

[0096] The corresponding NMR spectra of the products are as follows: Figure 8 and Figure 9 As shown, the data is as follows: 1H NMR(600MHz, CDCl3) δ7.47(d,J=8.3Hz,2H),7.20(d,J=8.4Hz,2H),5.82–5.7 3(m,2H),4.61(d,J=5.4Hz,1H),3.93(d,J=4.4Hz,2H),3.32(d,J=1.4Hz,6H). 13 C NMR (151MHz, CDCl3) δ140.1,133.0,131.7,129.3,128.6,121.6,83.2,72.4,58.2,56.6.

[0097] Example 6

[0098] Preparation of (E)-1,4-diether olefins

[0099] Prepared according to the reaction equation shown below:

[0100]

[0101] Z / E mixed 1,3-diene (Z / E = 57:43) (2 mmol) was added to a 10 mL reaction tube, and 116 mg was added to the 10 mL reaction tube. n Bu4NPF6 was reacted with 1.5 mL of tetrahydrofuran solvent and 1.5 mL of methanol solvent. The reaction was carried out at room temperature with a Pt sheet as the anode and graphite C as the cathode for 4 hours. The target product compound was obtained by column chromatography (petroleum ether PE: ethyl acetate EA volume ratio = 30:1) with a yield of 71%.

[0102] The corresponding NMR spectra of the products are as follows: Figure 10 and Figure 11 As shown, the data is as follows: 1 H NMR (600MHz, CDCl3) δ7.21(d,J=8.1Hz,2H),7.16(d,J=7.8Hz,2H),5.87–5.73(m,2H ),4.62(d,J=6.3Hz,1H),3.93(d,J=6.4Hz,2H),3.31(d,J=1.3Hz,6H),2.34(s,3H). 13 C NMR (151MHz, CDCl3) δ138.0,137.5,133.9,129.3,128.5,126.9,83.7,72.6,58.1,56.4,21.3.

[0103] Example 7

[0104] Preparation of (E)-1,4-diether olefins

[0105] Prepared according to the reaction equation shown below:

[0106]

[0107] Z / E mixed 1,3-diene (Z / E = 63:37) (2 mmol) was added to a 10 mL reaction tube, and 116 mg was added to the 10 mL reaction tube. n Bu4NPF6 was added, and 1.5 mL of tetrahydrofuran solvent and 1.5 mL of methanol solvent were added. The reaction was carried out at room temperature under a current of 10 mA with Pt sheet as anode and graphite C as cathode for 4 hours. The target product compound was obtained by column chromatography (petroleum ether PE: ethyl acetate EA volume ratio = 20:1) with a yield of 67%.

[0108] The corresponding NMR spectra of the products are as follows: Figure 12 and Figure 13 As shown, the data is as follows: 1 H NMR (600MHz, CDCl3) δ8.00(d,J=8.7Hz,2H),7.39(d,J=8.1Hz,2H),5.85–5.71(m,2H),4.69(d,J=6. 3Hz, 1H), 3.92 (d, J = 5.3Hz, 2H), 3.90 (d, J = 1.1Hz, 3H), 3.33 (d, J = 1.1Hz, 3H), 3.30 (d, J = 1.1Hz, 3H). 13 C NMR (151MHz, CDCl3) δ167.0,146.2,132.7,129.9,129.6,126.8,83.4,72.3,58.2,56.7,52.2.

[0109] Example 8

[0110] Preparation of (E)-1,4-diether olefins

[0111] Prepared according to the reaction equation shown below:

[0112]

[0113] Z / E mixed 1,3-diene (Z / E = 61:39) (2 mmol) was added to a 10 mL reaction tube, and 116 mg was added to the 10 mL reaction tube. nBu4NPF6 was added to 1.5 mL of tetrahydrofuran solvent and 1.5 mL of methanol solvent. The reaction was carried out at room temperature under a current of 10 mA with Pt sheet as anode and graphite C as cathode for 4 hours. The target product compound was obtained by column chromatography (petroleum ether PE: ethyl acetate EA volume ratio = 30:1) with a yield of 77%.

[0114] The corresponding NMR spectra of the products are as follows: Figure 14 , Figure 15 and Figure 16 As shown, the data is as follows: 1 H NMR(600MHz, CDCl3)δ7.60(d,J=8.0Hz,2H),7.44(d,J=7.9Hz,2H),5.87–5.7 1(m,2H),4.70(d,J=6.5Hz,1H),3.98–3.89(m,2H),3.34(s,3H),3.32(s,3H). 13 C NMR (101MHz, CDCl3) δ145.2, 132.7, 129.8 (d, J = 5.1Hz), 129.2, 127.1, 125.6 (q, J = 3.7Hz), 83.3, 72.3, 58.3, 56.7. 19 F NMR (377MHz, CDCl3) δ -62.50.

[0115] Example 9

[0116] Preparation of (E)-1,4-diether olefins

[0117] Prepared according to the reaction equation shown below:

[0118]

[0119] Z / E mixed 1,3-diene (Z / E = 62:38) (2 mmol) was added to a 10 mL reaction tube, and 116 mg was added to the 10 mL reaction tube. n Bu4NPF6 was added, followed by the addition of 1.5 mL of tetrahydrofuran solvent and 1.5 mL of methanol solvent. The reaction was carried out at room temperature under a 10 mA current with Pt sheet as the anode and graphite C as the cathode for 4 hours. The target product compound was obtained by column chromatography (petroleum ether PE: ethyl acetate EA volume ratio = 30:1) with a yield of 81%.

[0120] The corresponding NMR spectra of the products are as follows: Figures 17-19 As shown, the data is as follows: 1H NMR(600MHz, CDCl3)δ7.35(d,J=8.6Hz,2H),7.18(d,J=8.1Hz,2H),5.85–5.7 3(m,2H),4.65(d,J=5.9Hz,1H),3.94(d,J=4.3Hz,2H),3.32(d,J=2.1Hz,6H). 13 C NMR (151MHz, CDCl3) δ148.8 (d, J = 2.1Hz), 139.9, 133.0, 129.4, 128.3, 121.1, 120.6 (q, J = 258.2Hz), 83.1, 72.4, 58.3, 56.6. 19 F NMR (377MHz, CDCl3) δ -57.88.

[0121] Example 10

[0122] Preparation of (E)-1,4-diether olefins

[0123] Prepared according to the reaction equation shown below:

[0124]

[0125] Z / E mixed 1,3-diene (Z / E = 64:36) (2 mmol) was added to a 10 mL reaction tube, and 116 mg was added to the 10 mL reaction tube. n Bu4NPF6 was added, and 1.5 mL of tetrahydrofuran solvent and 1.5 mL of methanol solvent were added. The reaction was carried out at room temperature with a Pt sheet as the anode and a graphite C as the cathode at a current of 10 mA for 4 hours. The target product compound was obtained by column chromatography (petroleum ether PE: ethyl acetate EA volume ratio = 20:1) with a yield of 77%.

[0126] The corresponding NMR spectra of the products are as follows: Figure 20 and Figure 21 As shown, the data is as follows: 1 H NMR (600MHz, CDCl3) δ7.32(d,J=8.5Hz,2H),7.05(d,J=8.5Hz,2H),5.82–5.76( m,2H),4.64(d,J=4.4Hz,1H),3.92(d,J=2.9Hz,2H),3.31(s,6H),2.28(s,3H). 13 C NMR (101MHz, CDCl3) δ169.6,150.2,138.6,133.4,127.9,121.7,83.3,72.4,58.2,56.6,21.3.

[0127] Example 11

[0128] Preparation of (E)-1,4-diether olefins

[0129] Prepared according to the reaction equation shown below:

[0130]

[0131] 1,3-diene (Z / E = 58:42) (2 mmol) was added to a 10 mL reaction tube, and 116 mg was added to the 10 mL reaction tube. n Bu4NPF6 was added to 1.5 mL of tetrahydrofuran solvent and 1.5 mL of methanol solvent. The reaction was carried out at room temperature under a current of 10 mA with Pt sheet as anode and graphite C as cathode for 4 hours. The target product compound was obtained by column chromatography (petroleum ether PE: ethyl acetate EA volume ratio = 30:1) with a yield of 75%.

[0132] The corresponding NMR spectra of the products are as follows: Figure 22 and Figure 23 As shown, the data is as follows: 1 H NMR(600MHz, CDCl3)δ7.37–7.31(m,4H),7.28(d,J=6.1Hz,1H),5.79–5.70(m,1H), 5.61(dd,J=15.4,7.6Hz,1H),4.65(s,1H),3.74(dq,J=10.0,6.6,5.1Hz,1H),3.33 (d,J=2.8Hz,1.42H),3.32(d,J=2.4Hz,1.58H),3.28(d,J=2.1Hz,1.42H),3.21(d, J=2.1Hz,1.58H),1.26(dd,J=6.5,2.5Hz,1.58H),1.22(dd,J=6.6,2.5Hz,1.42H). 13 C NMR (151MHz, CDCl3) δ141.1,134.1,132.7,128.5,127.7,126.8,83.8,83.7,77.5,56.4,56.1,56.0,21.3.

[0133] Example 12

[0134] Preparation of (E)-1,4-diether olefins

[0135] Prepared according to the reaction equation shown below:

[0136]

[0137] Z / E mixed 1,3-diene (Z / E = 60:40) (2 mmol) was added to a 10 mL reaction tube, and 116 mg was added to the 10 mL reaction tube. n Bu4NPF6 was added, and 1.5 mL of tetrahydrofuran solvent and 1.5 mL of methanol solvent were added. The reaction was carried out at room temperature with a Pt sheet as the anode and a graphite C as the cathode for 4 hours. The target product compound was obtained by column chromatography (petroleum ether PE: ethyl acetate EA volume ratio = 20:1) with a yield of 55%.

[0138] The corresponding NMR data of the products are as follows: 1 H NMR(600MHz, CDCl3)δ8.01(d,J=8.3Hz,2H),7.39(d,J=8.3Hz,2H),5.85–5.72(m,2H) ,4.69(d,J=6.4Hz,1H),3.93(d,J=5.0Hz,2H),3.90(s,3H),3.33(s,3H),3.31(s,3H). 13 C NMR (151MHz, CDCl3) δ167.1,146.3,132.8,123.0,129.6,128.9,126.8,83.5,72.4,58.2,56.7,52.2.

[0139] Example 13

[0140] Preparation of (E)-1,4-diether olefins

[0141] Prepared according to the reaction equation shown below:

[0142]

[0143] Z / E mixed 1,3-diene (Z / E = 60:40) (2 mmol) was added to a 10 mL reaction tube, and 116 mg was added to the 10 mL reaction tube. n Bu4NPF6 was added to 1.5 mL of tetrahydrofuran solvent and 1.5 mL of methanol solvent. The reaction was carried out at room temperature under a current of 10 mA with Pt sheet as anode and graphite C as cathode for 4 hours. The target product compound was obtained by column chromatography (petroleum ether PE: ethyl acetate EA volume ratio = 10:1) with a yield of 79%.

[0144] The corresponding NMR data of the products are as follows: 1H NMR (600MHz, CDCl3) δ7.62(d,J=8.4Hz,2H),7.43(d,J=8.2Hz,2H),5.83(dt,J=15.4,5.4Hz,1H),5. 71(dd,J=15.6,7.1Hz,1H),4.68(d,J=7.1Hz,1H),3.93(d,J=5.4Hz,2H),3.34(s,3H),3.31(s,3H). 13 C NMR (151MHz, CDCl3) δ146.6,132.4,131.9,130.3,127.4,118.9,111.5,83.1,72.2,58.3,56.7.

[0145] Example 14

[0146] Preparation of (E)-1,4-diether olefins

[0147] Prepared according to the reaction equation shown below:

[0148]

[0149] Z / E mixed 1,3-diene (Z / E = 59:41) (2 mmol) was added to a 10 mL reaction tube, and 116 mg was added to the 10 mL reaction tube. n Bu4NPF6 was added to 1.5 mL of tetrahydrofuran solvent and 1.5 mL of methanol solvent. The reaction was carried out at room temperature under a current of 10 mA with Pt sheet as anode and graphite C as cathode for 4 hours. The target product compound was obtained by column chromatography (petroleum ether PE: ethyl acetate EA volume ratio = 30:1) with a yield of 73%.

[0150] The corresponding NMR data of the products are as follows: 1 H NMR(600MHz, CDCl3)δ7.82–7.77(m,2H),7.33(d,J=7.6Hz,2H),5.82–5.74(m,2H),4 .66(d,J=5.3Hz,1H),3.91(d,J=4.3Hz,2H),3.31(s,3H),3.29(s,3H),1.33(s,12H). 13 C NMR (151MHz, CDCl3) δ144.1,135.1,133.6,128.9,126.2,83.9,83.8,72.5,58.1,56.6,25.0.

[0151] Example 15

[0152] Preparation of (E)-1,4-diether olefins

[0153] The preparation is carried out according to the reaction equation shown below:

[0154]

[0155] Z / E mixed 1,3-diene (Z / E = 61:39) (2 mmol) was added to a 10 mL reaction tube, and 116 mg was added to the 10 mL reaction tube. n Bu4NPF6 was added, and 1.5 mL of tetrahydrofuran solvent and 1.5 mL of methanol solvent were added. The reaction was carried out at room temperature with a Pt sheet as the anode and a graphite C as the cathode at a current of 10 mA for 4 hours. The target product compound was obtained by column chromatography (petroleum ether PE: ethyl acetate EA volume ratio = 30:1) with a yield of 69%.

[0156] The corresponding NMR data of the products are as follows: 1 H NMR (600MHz, CDCl3) δ7.60–7.57(m,4H),7.44(t,J=7.8Hz,2H),7.40(d,J=8.2Hz,2H),7.37–7.33( m,1H),5.90–5.80(m,2H),4.71(d,J=5.6Hz,1H),3.96(d,J=4.5Hz,2H),3.36(s,3H),3.33(s,3H). 13 C NMR (151MHz, CDCl3) δ 141.0, 140.8, 140.1, 133.6, 128.9 (two peaks overlap), 127.4 (two peaks overlap), 127.2, 83.6, 72.6, 58.2, 56.6.

[0157] Example 16

[0158] Preparation of (E)-1,4-diether olefins

[0159] The preparation is carried out according to the reaction equation shown below:

[0160]

[0161] Z / E mixed 1,3-diene (Z / E = 80:20) (2 mmol) was added to a 10 mL reaction tube, and 116 mg was added to the 10 mL reaction tube. n Bu4NPF6 was added to 1.5 mL of tetrahydrofuran solvent and 1.5 mL of methanol solvent. The reaction was carried out at room temperature under a current of 10 mA with Pt sheet as anode and graphite C as cathode for 4 hours. The target product compound was obtained by column chromatography (petroleum ether PE: ethyl acetate EA volume ratio = 30:1) with a yield of 55%.

[0162] The corresponding NMR data of the products are as follows: 1 H NMR(600MHz, CDCl3)δ7.40(dt,J=15.3,7.8Hz,5H),7.33(t,J=7.2Hz,1H),7.22(m,1H),7.00(t,J=7.5Hz,1H),6.93(d, J=7.0Hz,1H),5.86–5.71(m,2H),5.20(d,J=5.8Hz,1H),5.09(s,2H),3.90(d,J=5.4Hz,2H),3.32(s,3H),3.29(s,3H). 13 C NMR (151MHz, CDCl3) δ155.9,137.2,133.1,129.7,128.7,128.6,128.0,127.9,127.4,127.2,121.3,112.0,77.1,72.7,70.2,58.0 56.7.

[0163] Example 17

[0164] Preparation of (E)-1,4-diether olefins

[0165] Prepared according to the reaction equation shown below:

[0166]

[0167] Z / E mixed 1,3-diene (Z / E = 77:23) (2 mmol) was added to a 10 mL reaction tube, and 116 mg was added to the 10 mL reaction tube. n Bu4NPF6 was added, and 1.5 mL of tetrahydrofuran solvent and 1.5 mL of methanol solvent were added. The reaction was carried out at room temperature with a Pt sheet as the anode and a graphite C as the cathode at a current of 10 mA for 4 hours. The target product compound was obtained by column chromatography (petroleum ether PE: ethyl acetate EA volume ratio = 10:1) with a yield of 57%.

[0168] The corresponding NMR data of the products are as follows: 1 H NMR (600MHz, CDCl3) δ7.37(d,J=7.6Hz,1H),7.23(d,J=8.2Hz,1H),6.99–6.94(m,1H),6.87(d,J=8.3Hz,1H),5.85–5 .74(m,2H),5.12(d,J=5.4Hz,1H),3.91(d,J=4.6Hz,2H),3.82(s,3H),3.33(d,J=1.2Hz,3H),3.29(d,J=1.3Hz,3H).13 C NMR (101MHz, CDCl3) δ156.9,133.2,129.3,128.6,127.8,127.1,121.0,110.7,72.8,58.0,56.7,55.6.

[0169] Example 18

[0170] Preparation of (E)-1,4-diether olefins

[0171] Prepared according to the reaction equation shown below:

[0172]

[0173] Z / E mixed 1,3-diene (Z / E = 73:27) (2 mmol) was added to a 10 mL reaction tube, and 116 mg was added to the 10 mL reaction tube. n Bu4NPF6 was added, followed by the addition of 1.5 mL of tetrahydrofuran solvent and 1.5 mL of methanol solvent. The reaction was carried out at room temperature under a 10 mA current with Pt sheet as the anode and graphite C as the cathode for 4 hours. The target product compound was obtained by column chromatography (petroleum ether PE: ethyl acetate EA volume ratio = 30:1) with a yield of 81%.

[0174] The corresponding NMR data of the products are as follows: 1 H NMR (600MHz, CDCl3) δ7.87–7.81(m,3H),7.79(s,1H),7.51–7.45(m,3H),5.92(dd,J=16.1,7.0Hz,1H) ,5.85(dt,J=15.7,5.5Hz,1H),4.83(d,J=6.4Hz,1H),3.95(d,J=5.8Hz,2H),3.38(s,3H),3.32(s,3H). 13 C NMR (151MHz, CDCl3) δ138.4,133.6,133.4,133.2,128.9,128.5,128.0,127.8,126.2,126.0,125.8,124.8,83.9,72.5,58.1,56.6.

[0175] Comparative Example 1

[0176] Preparation of (E)-1,4-diether olefins

[0177] Prepared according to the reaction equation shown below:

[0178]

[0179] Z / E mixed 1,3-diene (53:47)(2mmol) was added to a 10mL reaction tube, and 116mg was added to the 10mL reaction tube. n Bu4NPF6 was reacted with 1.5 mL of tetrahydrofuran solvent and 1.5 mL of methanol solvent. The reaction was carried out at room temperature with a Pt sheet as the anode and a graphite C as the cathode for 4 hours, but no product was obtained.

[0180] Comparative Example 2

[0181] Preparation of (E)-1,4-diether olefins

[0182] Prepared according to the reaction equation shown below:

[0183]

[0184] Z / E mixed 1,3-diene (62:38)(2mmol) was added to a 10mL reaction tube, and 116mg was added to the 10mL reaction tube. n Bu4NPF6 was reacted with 1.5 mL of tetrahydrofuran solvent and 1.5 mL of methanol solvent. The reaction was carried out at room temperature with a Pt sheet as the anode and a graphite C as the cathode for 4 hours, but no product was obtained.

[0185] The dienes used in Comparative Examples 1 and 2 were not very stable and neither could react.

[0186] Comparative Example 3

[0187] Prepared according to the reaction equation shown below:

[0188]

[0189] Z / E mixed 1,3-diene (Z / E = 59:41) (2 mmol) was added to a 10 mL reaction tube, and 116 mg was added to the 10 mL reaction tube. n Bu4NPF6 was added, followed by 3 mL of methanol solvent. The reaction was carried out at room temperature with a Pt sheet as the anode and a graphite C sheet as the cathode at a current of 10 mA for 4 hours, but no product was obtained.

[0190] Comparative Example 4

[0191]

[0192] Z / E mixed 1,3-diene (Z / E = 59:41) (2 mmol) was added to a 10 mL reaction tube, and 116 mg was added to the 10 mL reaction tube. nBu4NPF6 was reacted with 1.5 mL of tetrahydrofuran solvent and 1.5 mL of methanol solvent at room temperature for 4 hours, but no product was obtained.

[0193] Example 19

[0194]

[0195] The product was prepared according to a previously reported method (Nat. Commun., 2021, 12, 6700). In a 10 mL Shrek tube, (E)-1,4-diether olefin (2 mmol), m-chloroperoxybenzoic acid (m–CPBA) (4 mmol), dichloromethane (3 mL), and a magnetic stir bar were added to air. The reaction mixture was stirred at room temperature for 20 hours. The solvent was removed under reduced pressure, and the target product compound was isolated by column chromatography (petroleum ether PE: ethyl acetate EA v / v = 20:1) in 83% yield.

[0196] The corresponding NMR data of the products are as follows: 1 H NMR(600MHz, CDCl3)δ8.09(s,0.63H),8.00(d,J=7.8Hz,0.7H),7.60–7.57(m,0.66H),7.42(t,J=7.9Hz, 0.85H),7.39–7.36(m,1.49H),7.34(d,J=6.3Hz,2.45H),4.25(d,J=4.0Hz,0.5H),4.00(d,J=6.3Hz,0.28 H),3.69(dd,J=11.7,2.9Hz,0.55H),3.62–3.51(m,0.4H),3.44(d,J=7.2Hz,0.27H),3.36(s,H),3.37(d ,J=6.3Hz,2.92H),3.33–3.27(m,3.2H),3.12(dd,J=6.4,2.2Hz,0.29H),3.06(dd,J=3.9,2.3Hz,0.79H). 13 C NMR (151MHz, CDCl3) δ 170.4, 138.1, 134.8, 133.9, 131.2, 130.3, 130.0, 128.8, 128.7, 128.5 (two peaks overlap), 128.4, 127.4, 127.0, 84.2, 81.8, 72.2, 72.0, 59.2, 59.1, 58.5, 57.7, 57.3, 54.9, 54.3.

[0197] Example 20

[0198]

[0199] The preparation was performed according to a previously reported method (Nanoscale, 2015, 7, 17786-17790). In a 10 mL Shrek tube, (E)-1,4-diether olefin (2 mmol), Pd / C (0.4 mmol), dichloromethane (3 mL), and a magnetic stir bar were added under a hydrogen atmosphere. The reaction mixture was stirred at room temperature for 12 hours, and the target product compound was obtained by column chromatography (petroleum ether PE: ethyl acetate EA, v / v = 30:1) in 94% yield.

[0200] The corresponding NMR data of the products are as follows: 1 H NMR (600MHz, CDCl3) δ7.37–7.32(m,2H),7.31–7.26(m,3H),4.11(dd,J=7.5,5.2Hz,1H),3.40–3 .32(m,2H),3.30(s,3H),3.21(s,3H),1.86–1.81(m,1H),1.76–1.64(m,2H),1.60–1.49(m,1H). 13 C NMR (151MHz, CDCl3) δ142.3,128.4,127.6,126.7,83.9,72.7,58.6,56.7,34.8,26.1.

[0201] Example 21

[0202]

[0203] The product was prepared according to a previously reported method (J. Org. Chem., 22003, 68, 3721-3724). In a 10 mL Shrek tube, (E)-1,4-diether olefin (2 mmol), Na₂CO₃ (6 mmol), dichloromethane (6 mL), and a magnetic stir bar were added to air. CSI (chlorosulfonyl isocyanate) (3 mmol) was added dropwise at 0 °C, and the reaction mixture was stirred at 0 °C for 8 hours. Then, Na₂SO₃ (6 mmol) and KOH (6 mmol) were added at 0 °C, and the reaction mixture was stirred at room temperature for 8 hours. The target product compound was isolated by column chromatography (petroleum ether PE: ethyl acetate EA, v / v = 10:1) in a yield of 67%.

[0204] The corresponding NMR data of the products are as follows: 1H NMR (600MHz, CDCl3) δ7.39–7.34(m,2H),7.33–7.27(m,2H),7.25–7.19(m,1H),6.58(d,J=15.9Hz,1H),6.1 9(dd,J=16.0,6.3Hz,1H),5.35–5.19(m,1H),4.51(s,1H),3.69(s,3H),3.52(d,J=4.4Hz,2H),3.37(s,3H). 13 C NMR (151MHz, CDCl3) δ156.6,136.6,131.4,128.6,127.7,127.4,74.8,59.2,52.7,52.2.

[0205] Example 22

[0206]

[0207] The Z / E mixed 1,3-diene prepared in Example 1 (Z / E = 59:41) (2 mmol) was placed in a 10 mL reaction tube, and 116 mg was added to the 10 mL reaction tube. n Bu4NPF6 was added to 1.5 mL of tetrahydrofuran solvent and 1.5 mL of methanol solvent. The reaction was carried out at room temperature with a Pt sheet as the anode and a graphite C as the cathode for 4 hours. The target product compound was obtained by column chromatography (petroleum ether PE: ethyl acetate EA volume ratio = 30:1) with a yield of 57%.

[0208] Example 23

[0209]

[0210] The Z / E mixed 1,3-diene prepared in Example 1 (Z / E = 59:41) (2 mmol) was placed in a 10 mL reaction tube, and 116 mg was added to the 10 mL reaction tube. n Bu4NPF6 was added to 1.5 mL of tetrahydrofuran solvent and 1.5 mL of methanol solvent. The reaction was carried out at room temperature under a current of 15 mA with Pt sheet as anode and graphite C as cathode for 4 hours. The target product compound was obtained by column chromatography (petroleum ether PE: ethyl acetate EA volume ratio = 30:1) with a yield of 77%.

[0211] As demonstrated in Examples 19-21, the (E)-1,4-diether olefins synthesized in this invention can serve as organic synthesis intermediates. Specifically, the double bonds of the (E)-1,4-diether olefins can be easily epoxidized with m-chloroperoxybenzoic acid (m-CPBA) as an oxidant to obtain ethylene oxide derivatives in extremely high yields (Nat. Commun., 2021, 12, 6700), and ethylene oxide is an extremely important chemical raw material. The (E)-1,4-diether olefins can also be reduced in the presence of 1 atm hydrogen and palladium / carbon (Pd / C) to convert into straight-chain alkanes containing ether bonds in high yields (Nanoscale, 2015, 7, 17786-17790), which are suitable for flexible linking units in functional materials. Furthermore, its allyl group can be amination-mediated to provide an advantageous backbone for drug molecule screening (J. Org. Chem., 2003, 68, 3721-3724).

[0212] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing (E)-1,4-diether olefins, characterized in that: The (E)-1,4-diether olefin is obtained by an electrochemical reaction using 1,3-diene as a raw material in the presence of an electrolyte and a solvent; wherein the structural formula of the 1,3-diene is as follows: R 1 It is one of phenyl, p-fluorophenyl, p-chlorophenyl, p-bromophenyl, p-methylphenyl, p-methoxyphenyl, p-trifluoromethylphenyl, p-trifluoromethoxyphenyl, p-acetoxyphenyl, p-methyl p-formate phenyl, p-cyanophenyl, p-pinacol p-borate phenyl, p-phenylenephenyl, o-oxobenzylphenyl, o-methoxyphenyl, and 2-naphthyl, and the wavy line in the structural formula represents the ZE isomer; the solvent is a mixed solvent containing methanol.

2. The method for preparing (E)-1,4-diether olefins according to claim 1, characterized in that: In 1,3-diene, Z / E = 57-80:20-43.

3. The method for preparing (E)-1,4-diether olefins according to claim 1, characterized in that: The structural formula of the 1,3-diene is as follows: One of them.

4. The method for preparing (E)-1,4-diether olefins according to claim 1, characterized in that: The electrochemical reaction uses platinum sheets and graphite as electrodes.

5. The method for preparing (E)-1,4-diether olefins according to claim 1, characterized in that: The electrolyte is one or a mixture of tetrabutyltetrafluoroborate, tetrabutylacetic acid, and tetrabutylammonium hexafluorophosphate.

6. The method for preparing (E)-1,4-diether olefins according to claim 1, characterized in that: The solvent is one of the following: a mixture of tetrahydrofuran and methanol, a mixture of toluene and methanol, a mixture of acetonitrile and methanol, or a mixture of dichloroethane and methanol.

7. The method for preparing (E)-1,4-diether olefins according to claim 1, characterized in that: The electrochemical reaction has a current of 5-15 mA and a time of 1-4 hours.

8. The method for preparing (E)-1,4-diether olefins according to claim 1, characterized in that: The ratio of 1,3-diene to solvent is 2 mmol:3 mL; the ratio of electrolyte to solvent is 0.1 mmol:1 mL; and the ratio of 1,3-diene to methanol is 2 mmol:1.5 mL.

9. The method for preparing (E)-1,4-diether olefins according to any one of claims 1-8, characterized in that: Includes the following steps: The 1,3-diene was mixed with an electrolyte, and then a solvent was added. The reaction was carried out under electrolysis to obtain the (E)-1,4-diether olefin.

10. A (E)-1,4-diether olefin, characterized in that: Its structural formula is shown in Formula I: In Equation I, R 1 It is one of the following: phenyl, p-fluorophenyl, p-chlorophenyl, p-bromophenyl, p-methylphenyl, p-methoxyphenyl, p-trifluoromethylphenyl, p-trifluoromethoxyphenyl, p-acetoxyphenyl, p-methyl p-formate phenyl, p-cyanophenyl, p-pinacol p-borate phenyl, p-phenylenephenyl, o-oxobenzylphenyl, o-methoxyphenyl, 2-naphthyl; R 2 It is a methyl group.

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