A method for synthesizing tri-substituted and tetra-substituted olefins by alkylation of non-terminal olefins

Abstract

The invention discloses a method for synthesizing tri-substituted and tetra-substituted olefins by alkylation of non-terminal olefins. The non-terminal olefins and sulfoxides undergo alkylation reaction in the presence of iron salt and hydrogen peroxide. The di-substituted non-terminal olefins react in one pot to generate tri-substituted olefins, and the tri-substituted non-terminal olefins react in one pot to generate tetra-substituted olefins. In the method, sulfoxides are simultaneously used as alkylation reagents and solvents for olefins. The reaction product has one more alkyl substituent on the double-bonded carbon atom than the reactant, thereby increasing the olefin carbon chain. The reaction conditions are mild, the selectivity is good, the yield is high, and the method is conducive to industrial production.

Description

Technical Field

[0001] The invention relates to a method for synthesizing tri-substituted and tetra-substituted olefins, in particular to a method for synthesizing tri-substituted and tetra-substituted olefins by alkylation of non-terminal olefins, and belongs to the field of organic synthesis. Background Art

[0002] Olefins are a class of widely used organic compounds, and many compounds in nature also contain olefins of different structures. Steroidal terpenoids that have neurophysiological effects in organisms are also olefin compounds with different structures. At present, among the synthesis methods of olefins with different structures, the alkylation of lower olefins is the most commonly used and one of the most effective methods for synthesizing higher olefins (Z. Chen, M.-Y. Rong, J. Nie, X.-F. Zhu, B.-F. Shi and J.-A. Ma, Chem. Soc. Rev., 2019, 48, 4921; T. Irrgang and R. Kempe, Chem. Rev. 2019, 119, 2524; C. Shan, L. Zhu, L.-B. Qu, R. Bai and Y. Lan, Chem. Soc. Rev., 2018, 47, 7552; Z. Dong, Z. Ren, S. Thompson, Y. Xu and G. Dong, Chem. Rev. 2017, 117, 9333). The Heck reaction for the coupling synthesis of halogenated hydrocarbons and olefins under palladium catalysis is a classic direct alkylation reaction of olefins (RF Heck and JP Nolley, J. Org. Chem., 1972, 37, 2320; IP Beletskaya and AV Cheprakov, Chem. Rev., 2000, 100, 3009; AB Dounay and LE Overman, Chem. Rev., 2003, 103, 2945; KC Nicolaou, PG Bulger and D. Sarlah, Angew. Chem., Int. Ed., 2005, 44, 4442; C. Torborg and M. Beller, Adv. Synth. Catal., 2009, 351, 3027; X.-F. Wu, P. Anbarasan, H. Neumann and M. Beller, Angew. Chem., Int. Ed., 2010, 49, 9047; F. Akiyama, H. Miyazaki, K. Kaneda, S. Teranishi, Y. Fujiwara, M. Abe and H. Taniguchi, J. Org. Chem., 1980, 45, 2359). In the past few decades, many organic synthesis workers have proposed some improved Heck reactions to synthesize various olefins.Fujiwara proposed a method for synthesizing 1,2-disubstituted methyl aromatic olefins by using alkylamine as an alkylating agent and a monoaryl-substituted terminal olefin under palladium salt catalysis (Scheme 1, (1a)) (Y. Ikeda, T. Nakamura, H. Yorimitsu and K. Oshima, J. Am. Chem. Soc., 2002, 124, 6514); Oshima proposed a method for synthesizing 1,2-disubstituted methyl aromatic olefins by using halogenated hydrocarbons as an alkylating agent and a monoaryl-substituted terminal olefin under cobalt salt catalysis (Scheme 1, (1b)) (W. Affo, H. Ohmiya, T. Fujioka, Y. Ikeda, T. Nakamura, H. Yorimitsu, K. Oshima, Y. Imamura, T. Mizuta and K.Miyoshi, J.Am.Chem.Soc., 2006, 128, 8068); Brown reported a method for the methylation reaction of N-methyl-N-methylsilyl urea as a methylating agent with aromatic terminal olefins and multi-substituted aromatic terminal olefins to produce methyl aromatic olefins (Scheme 1, (1c))(W.Rauf and JM Brown, Angew.Chem., Int.Ed., 2008, 47, 4228); Bao reported a method for the use of hydrocarbon peroxy esters as hydrocarbon alkylating agents with aromatic terminal olefins under the catalysis of iron complexes to produce 1,2-disubstituted hydrocarbon aromatic olefins (Scheme 1, (1d))(N.Zhu, J.Zhao and H.Bao, Chem.Sci., 2017, 8, 2081). These disclosed methods achieve the alkylation of olefin carbon-hydrogen bonds via an ionization process (Scheme 1, (1a, 1b, 1c)) or a free radical process (Scheme 1, (1d)), but use difficult to obtain complex carbon-halogen bond, carbon-nitrogen bond, carbon-oxygen bond compounds as alkylation agents, and also use expensive metal catalysts. These shortcomings make the above-mentioned methods for preparing olefins difficult to apply on an industrial scale. At the same time, these methods can only be used for the alkylation of non-terminal olefins to prepare polysubstituted olefins.

[0003] Summary of the invention

[0004] In view of the defect that non-terminal olefins cannot be directly hydrocarbylated to synthesize trisubstituted and tetrasubstituted olefins, the purpose of the present invention is to provide a method for hydrocarbylating non-terminal olefin substrates using sulfoxide as a hydrocarbylating agent. The synthesis method uses a one-pot reaction, and a hydrogen atom on the olefin carbon is replaced by a hydrocarbyl group to obtain a product in which an olefin carbon atom is coupled with a hydrocarbyl olefin from a sulfoxide hydrocarbyl group; a disubstituted non-terminal olefin generates a trisubstituted olefin, and a trisubstituted non-terminal olefin generates a tetrasubstituted olefin; the raw materials are easily available, and the reaction conditions are mild, the selectivity is good, and the yield is high, which is conducive to industrial production.

[0005] The non-terminal olefin has the structure of Formula 1:

[0006]

[0007] The sulfoxide has a structure of Formula 2:

[0008]

[0009] in,

[0010] R is an alkyl group such as methyl, ethyl, phenyl, benzyl, etc.;

[0011] R1 or R2 or R3 can be a simple aromatic ring group or a substituted aromatic ring group or a C1-C 10 The substituted aryl group contains 1 to 2 substituents, and the substituents are selected from at least one of halogen substituents, alkyl, hydroxyl, amino, nitro, aldehyde, and carboxyl groups. The halogen substituents are fluorine, chlorine, bromine, iodine, etc., and the alkyl group is C1 to C 10 alkyl, more preferably a C1-C5 short-chain alkyl, such as methyl, ethyl, propyl, etc., and may also be a branched alkyl, such as isopropyl, tert-butyl, etc.; R3 cannot be hydrogen, R1 or R2 can be hydrogen, but R1 and R2 cannot be hydrogen at the same time;

[0012] The metal salt can be an iron salt, a copper salt, a nickel salt, or a cobalt salt, preferably an iron salt;

[0013] The peroxide is hydrogen peroxide, tert-butyl hydroperoxide, di-tert-butane peroxide, preferably hydrogen peroxide.

[0014] In a preferred embodiment, the ratio of hydrogen peroxide to terminal olefin is 2 to 8:1, more preferably 4:1.

[0015] In a preferred embodiment, the reaction temperature is 80-160°C, more preferably 140°C.

[0016] In a preferred embodiment, the reaction conditions are: in an atmospheric atmosphere, at a temperature of 80 to 160° C., for 2 to 12 hours. More preferred conditions are: in an atmospheric atmosphere, at a temperature of 140° C., for 6 hours.

[0017] The present invention uses the reaction of styrene and dimethyl sulfoxide to synthesize (Z)-2-methylstyrene to illustrate the reaction mechanism. After consulting and referring to relevant literature, a series of mechanism research experiments were designed. The results are shown in Scheme 2:

[0018]

[0019] First, under standard reaction conditions, a small amount of free radical scavenger 2,6-di-tert-butyl-4-methylphenol (BHT) was added, and the reaction of styrene with DMF to generate the desired product (Z)-2-methylstyrene was inhibited, and the methyl radical extraction product E and the 1-phenylpropyl radical A extraction product D were detected (Scheme 2.a), indicating that the reaction was a free radical reaction and that methyl radicals and 1-phenylpropyl radicals A were present. In addition, the deuterated product of (Z)-2-methylstyrene was obtained by the reaction of styrene with deuterated DMF (Scheme 2.f), indicating that in the reaction, DMF is a hydrocarbon-forming agent that provides hydrocarbon groups to the double bond carbons of styrene. When there is no Fe 3+ When the reaction product (Z)-2-methylstyrene is added with H2O2, it is almost impossible to detect the reaction product (Z)-2-methylstyrene (Scheme 2.c), and no methyl radical is detected (Scheme 2.c). The product of the reaction under standard conditions for 1 hour was detected by GC-MS, and the presence of intermediate F was found (Scheme 6.d). Further research found that the product (Z)-2-methylstyrene (Scheme 6.e) can be obtained with a yield of 95% under standard conditions using intermediate F as a raw material, indicating that the intermediate in the reaction of olefins and sulfoxides to generate alkyl olefins in the presence of iron salts and hydrogen peroxide is compound F.

[0020] Based on the above experimental results, the following reaction mechanism (Scheme 3) is proposed for the reaction of olefins and sulfoxides to generate alkyl olefins in the presence of iron salts and hydrogen peroxide. 3+ or Fe 2+ The hydroxyl radical OH· is generated, and then the hydroxyl radical OH· reacts with DMSO to generate a methyl radical CH3·. Further, the methyl radical CH3· reacts with styrene to generate a 1-phenylpropyl radical A. Then, the 1-phenylpropyl radical A is coupled with the hydroxyl radical OH· to obtain the intermediate F. Finally, under heating conditions, the intermediate F undergoes trans-elimination dehydration to obtain the product (Z)-2-methylstyrene.

[0021]

[0022] The technical solution of the present invention is that sulfoxide is used as a hydrocarbylating agent to react with non-terminal olefins to generate a hydrocarbyl olefin by a substitution reaction of the carbon-hydrogen bond on the double bond atom, a disubstituted non-terminal olefin generates a trisubstituted olefin, and a trisubstituted non-terminal olefin generates a tetrasubstituted olefin, and a hydrocarbyl carbon chain is added to the double bond carbon atom of the raw non-terminal olefin. Sulfoxide mainly plays two roles. On the one hand, it plays the role of a benign solvent, and on the other hand, as a reaction substrate, sulfoxide provides an alkyl group as a hydrocarbyl group on the double bond of the product; the structure or structural unit of the peroxide does not appear in the product structure, but the peroxide is necessary in the reaction of the olefin and sulfoxide to generate a hydrocarbyl group, and the role of the peroxide is to provide hydroxyl radicals. Hydroxyl radicals have two roles: reacting with sulfoxide to generate alkyl radicals; reacting with olefin alkylation radicals to generate hydroxyl products. The role of metal ions is to promote the formation of hydroxyl radicals from peroxides.

[0023] Compared with the prior art, the technical solution of the present invention brings the following beneficial technical effects:

[0024] 1) The method for synthesizing tri-substituted and tetra-substituted olefins by alkylation of non-terminal olefins proposed in the present invention can directly add a hydrocarbon group to the double bond carbon atom of the non-terminal olefin through alkylation reaction to extend the carbon chain, thus making up for the defect that the existing non-terminal olefins are difficult to directly alkylate;

[0025] 2) The raw materials used in the method for synthesizing tri-substituted and tetra-substituted olefins by alkylation of non-terminal olefins proposed by the present invention are non-terminal olefins and sulfoxides, and the auxiliary reagents iron salt and hydrogen peroxide are some common common chemical raw materials, which are low in cost and have a wide source of raw materials, and are conducive to industrial production;

[0026] 3) The method for synthesizing tri-substituted and tetra-substituted olefins by alkylation of non-terminal olefins proposed in the present invention adopts a one-pot reaction to form the product, which is simple to operate and convenient for industrial application;

[0027] 4) The method for synthesizing tri-substituted and tetra-substituted olefins by alkylation of non-terminal olefins proposed in the present invention reacts in an atmospheric atmosphere, has mild conditions, is simple to operate, and meets industrial production requirements;

[0028] 5) The method for synthesizing tri-substituted and tetra-substituted olefins by alkylation of non-terminal olefins proposed in the present invention has a wide range of adaptability to substrate raw materials, and various tri-substituted and tetra-substituted olefins can be constructed by selecting appropriate substrate structures. DETAILED DESCRIPTION

[0029] The following examples are intended to further illustrate the present invention, rather than to limit the scope of protection of the claims of the present invention.

[0030] Unless otherwise stated, all reactions were performed in Schlenk tubes.

[0031] All reaction starting solvents were obtained from commercial sources and used without further purification.

[0032] The products were separated using a silica gel chromatographic column, silica gel (particle size 300-400 mesh).

[0033] 1H NMR (400 MHz), 13C NMR (100 MHz) and 19F NMR (376 MHz) were detected using a Bruker ADVANCE III spectrometer, with CDCl3 as solvent, TMS as internal standard, chemical shifts in parts per million (ppm), with 0.0 ppm of tetramethylsilane as reference shift. The following abbreviations (or combinations thereof) are used to explain multiplicity: s = singlet, d = doublet, t = triplet, q = quartet, m = multiplet, br = broad. The unit of coupling constant J is Hertz (Hz). Chemical shifts are expressed in ppm, with reference to the center line of the triplet state of deuterated chloroform at 77.0 ppm or the center line of the septet state of deuterated DMSO at 39.52 ppm.

[0034] GC-MS was detected by GC-MS QP2010 equipment, HRMS was measured by electron ionization (EI) method, the mass analyzer type was TOF, and EI was detected by Esquire 3000plus instrument.

[0035] 1. Condition optimization experiment:

[0036] Taking the synthesis of (Z)-2-methylstyrene from styrene and dimethyl sulfoxide as an example, the types of metal salts used in the reaction, the types and amounts of peroxides, the reaction temperature, etc. were screened to find the best reaction conditions.

[0037]

[0038] 1.1 Screening of metal salts

[0039] First, the types of metal salts used in the reaction were screened. Divalent iron, copper, nickel, cobalt and trivalent iron salts were screened, and the results are shown in Table 1. All metal salts can obtain reaction products, but divalent iron salts and trivalent iron salts have higher yields than other metal salts.

[0040] Table 1. Screening of metal salt types

[0041]

[0042]

[0043] 1.2 Selection of peroxide types and dosage

[0044] The types and dosages of different peroxides were screened under standard conditions. The peroxides used were commonly used hydrogen peroxide, dibenzoyl peroxide (BPO), di-tert-butyl peroxide (DTBP), tert-butyl hydroperoxide (TBHP) and potassium peroxydisulfate (K2S2O8). The screening results are shown in Table 2. Dibenzoyl peroxide and potassium peroxydisulfate almost did not produce any product, and hydrogen peroxide had the best effect. Experiments using different amounts of hydrogen peroxide showed that 6 equivalents of hydrogen peroxide gave the highest yield.

[0045] Table 2. Screening of peroxides

[0046]

[0047] 1.3 Screening of reaction temperature

[0048] Reaction temperature is an important factor affecting the reaction yield, and the effect of gradient temperature on the reaction was further studied, and the results are shown in Table 3. The experiment was carried out from 80°C to 160°C, and the reaction yield was the highest at 140°C.

[0049] Table 3. Screening of reaction temperature

[0050]

[0051] 1.4 Standard reaction process

[0052] The standard reaction process obtained after the above optimization is as follows: 3 ml DMSO, 0.5 mmol non-terminal olefin, 2 mmol (4.0 equiv) 30% H2O2, and 15 mg FeCl3.6H2O are added to a 25 ml Schlenk tube, respectively. After mixing evenly, the reaction tube is sealed with a sealing plug and placed in a 140 ° C oil bath pot for magnetic stirring and heating. After the reaction is stopped for 6 hours, the product is extracted with ethyl acetate after the reaction tube is cooled. After the extract is washed with water to remove DMSO, it is dried with anhydrous Na2SO4 and finally the solvent is dried in vacuum. The dried sample is separated by silica gel column chromatography with petroleum ether / ethyl acetate as the eluent to obtain the product, which is vacuum dried and characterized by NMR, MS, and MS.

[0053] 1.5 Special reaction process

[0054] Add 3ml DMSO, 0.25mmol non-terminal olefin, 1mmol (4.0equiv) 30% H2O2, 15mg FeCl3.6H2O to a 25ml Schlenk tube, mix well, seal the reaction tube with a sealing plug, and heat and stir in a 160℃ oil bath with magnetic stirring. Stop heating after 12h of reaction, and extract the product with ethyl acetate after the reaction tube cools down. Wash the extract with water to remove DMSO, dry it with anhydrous Na2SO4, and finally vacuum dry the solvent. The dried sample is separated by silica gel column chromatography with petroleum ether / ethyl acetate as eluent to obtain the product, which is vacuum dried and characterized by NMR, MS, and MS.

[0055] 2. Synthesis Example

[0056] Under standard reaction conditions, the present invention uses different non-terminal olefin substrates and sulfoxide to synthesize some trisubstituted and tetrasubstituted olefin products, and the structures of these products are shown in Table 4 below. When the double bonds of the non-terminal olefin raw materials are all aryl groups (see products f, h, i, j, l) or all hydrocarbon groups (see product b), the carbon-hydrogen bonds on the double bond carbon atoms can be alkylated to form corresponding trisubstituted and tetrasubstituted olefin products; when the non-terminal olefin raw materials are olefins with both aryl and non-aryl groups on the double bonds (see products a, c, d, e, g, k), they can also be alkylated to form corresponding trisubstituted and tetrasubstituted olefin products; when the non-terminal olefin raw materials are disubstituted olefins with both aryl and non-aryl groups on the double bonds, the newly introduced hydrocarbon groups in the products are connected to the non-aryl carbon atoms (see products a, c, d, e), and the product yields are affected by the electronic effect of the non-hydrocarbon groups on the double bonds of the raw materials and the stereo effect of the hydrocarbon groups in the sulfoxide alkylation agent. The electron-withdrawing group of the non-hydrocarbon group on the double bond of the raw material can obtain a higher product yield than the electron-donating group; the larger the volume of the hydrocarbon group in the sulfoxide hydrocarbonization reagent, the lower the product yield.

[0057] Table 4 Synthesized trisubstituted and tetrasubstituted olefin products

[0058]

[0059] Reaction conditions: olefin (0.25mmol, 1.0eq), FeCl3 (0.1mmol), DMSO (2ml), heated at 140℃ in a pressure tube for 6h. The yield is the isolated yield.

[0060] Structural characterization of some alkyl olefin products

[0061] (2-methylprop-1-en-1-yl)benzene(a):

[0062]

[0063] The product was synthesized according to the standard reaction process, and separated and purified by silica gel column chromatography, using 100:1 petroleum ether and ethyl acetate as eluent. The product was a colorless liquid, 21.12 mg, and a yield of 32%. The structural analysis data are as follows: 1 H NMR (400MHz, Chloroform-d) δ7.39(m,2H),7.34–7.29(m,2H),7.28–7.22 (m,1H),6.37(s,1H),1.99(s,3H),1.95(s,3H). 13 C NMR(101MHz,Chloroform-d)δ 138.67,135.30,128.70,127.97,125.73,125.16,26.80,19.32.

[0064] 1-methylcyclohex-1-ene(b):

[0065]

[0066] The product was synthesized according to the standard reaction process, and separated and purified by silica gel column chromatography, using 100:1 petroleum ether and ethyl acetate as eluent. The product was a colorless liquid, 16.81 mg, and a yield of 35%. The structural analysis data are as follows: 1 H NMR (400MHz, CDCl3) δ1.50-1.63(m,4H),1.63(s,3H),1.89-1.99(m,4H),5.39(m,1H); 13 C NMR (100MHz, CDCl3) δ22.4, 23.0, 24.0, 25.3, 30.0, 121.1, 134.1;

[0067] (E)-3-methyl-4-phenylbut-3-en-2-one(c):

[0068]

[0069] The product was synthesized according to the standard reaction process, and separated and purified by silica gel column chromatography, using 30:1 petroleum ether and ethyl acetate as eluent. The product was a yellow solid, 45.26 mg, with a yield of 62%. The structural analysis data are as follows: 1 H NMR (400MHz, Chloroform-d) δ7.51 (s, 1H), 7.41 (d, J = 4.4Hz, 4H), 7.33 (m, 1H), 2.45 (s, 3H), 2.05 (s, 3H). 13C NMR(101MHz,Chloroform-d)δ200.26,139.65, 137.76,135.92,129.69,128.55,128.46,25.83,12.93.

[0070] (E)-2-methyl-3-phenylacrylic acid(d):

[0071]

[0072] The product was synthesized according to the standard reaction process, and separated and purified by silica gel column chromatography, using 10:1 petroleum ether and ethyl acetate as eluent. The product was a colorless liquid, 44.48 mg, with a yield of 60%. The structural analysis data are as follows: 1 H NMR (400MHz, Chloroform-d) δ11.88(s,1H),7.86(s,1H),7.42(m,4H),7.37(m,1H),2.17(s,3H). 13 C NMR (101MHz, Chloroform-d) δ175.36,142.12,136.59, 130.83,129.69,129.43,128.57,14.70.

[0073] (E)-2-methyl-3-phenylacrylaldehyde(e):

[0074]

[0075] The product was synthesized according to the standard reaction process, and separated and purified by silica gel column chromatography, using 30:1 petroleum ether and ethyl acetate as eluent. The product was a colorless liquid, 47.52 mg, with a yield of 72%. The structural analysis data are as follows: 1 H NMR (400MHz, Chloroform-d) δ9.62 (d, J = 1.8 Hz, 1H), 7.57 (m, 2H), 7.52–7.38 (m, 3H), 7.30 (s, 1H), 2.11 (s, 3H). 13 C NMR(101MHz,Chloroform-d)δ196.51, 150.77,139.32,136.09,130.98,130.52,129.66,11.90.

[0076] (E)-Prop-1-ene-1,2-diyldibenzene(f):

[0077]

[0078] The product was synthesized according to the standard reaction process and separated and purified by silica gel column chromatography with 10:1 petroleum ether and ethyl acetate as eluent. The product was a white solid, 45.62 mg, 47% yield. The structural analysis data are as follows: 45.62 mg, 47% yield, white solid, 1 H NMR (300MHz, CDCl3, δppm): 2.12 (s, 3H), 6.94 (s, 1H), 7.17-7.32 (m, 10H); 13 C NMR (75MHz, CDCl3, δppm): 19.7, 124.9, 126.5, 128.0, 128.3, 129.2, 136.3, 141.8, 144.9;

[0079] (2-methylprop-1-ene-1,1-diyl)dibenzene(g):

[0080]

[0081] The product was synthesized according to the standard reaction process and separated and purified by silica gel column chromatography with 100:1 petroleum ether and ethyl acetate as eluent. The product was a colorless liquid, 52 mg, 50% yield. The structural analysis data are as follows: 52.00 mg, 50% yield, colorless liquid, 1 H NMR (400MHz, Chloroform-d) δ7.31 (m, 1H), 7.20 (m, 1H), 1.85 (s, 1H). 13 C NMR(101MHz,Chloroform-d)δ144.32,131.96, 130.80,128.82,127.00,23.45.

[0082] Prop-1-ene-1,1,2-triyltribenzene(h):

[0083]

[0084] The product was synthesized according to the standard reaction process, and separated and purified by silica gel column chromatography, using 100:1 petroleum ether and ethyl acetate as eluent. The product was a white solid, 52.50 mg, with a yield of 51%. 1H NMR (400MHz, Chloroform-d) δ7.43(m,2H),7.34(m,3H),7.24–7.20(m,4H),7.09(m,3H),7.02–6.96(m,3H),2.22(s,3H). 13 CNMR(101MHz,Chloroform-d)δ145.00,144.50, 144.03,140.32,136.66,131.80,130.95,130.25,129.08,128.81,128.37,127.54,127.16,126.77,24.31.

[0085] Ethene-1,1,2-triyltribenzene(i):

[0086]

[0087] The product was synthesized according to a special reaction process and separated and purified by silica gel column chromatography with 100:1 petroleum ether and ethyl acetate as eluent. The product was a white solid, 12.80 mg, with a yield of 20%. The structural analysis data are as follows: 1 H NMR (400MHz, Chloroform-d) δ7.33 (s, 8H), 7.24–7.18 (m, 2H), 7.13 (m, 3H), 7.03 (d, J = 7.3Hz, 2H), 6.97 (s, 1H). 13 C NMR(101MHz,Chloroform-d)δ144.42, 143.58,141.35,138.38,131.38,130.53,129.61,129.18,129.15,128.94,128.59,128.48,128.38,127.72.

[0088] 1,1,2,2-tetraphenylethene(j):

[0089]

[0090] The product was synthesized according to a special reaction process and separated and purified by silica gel column chromatography with 100:1 petroleum ether and ethyl acetate as eluent. The product was a white solid, 30.71 mg, with a yield of 37%. The structural analysis data are as follows: 1 H NMR (400MHz, Chloroform-d) δ7.10 (d, J = 5.5 Hz, 1H), 7.03 (dd, J = 6.2, 2.8 Hz, 1H). 13C NMR (101MHz, Chloroform-d) δ144.70, 141.94, 132.30, 128.61, 127.38.

[0091] Prop-1-ene-1,1,2-triyltribenzene(k):

[0092]

[0093] The product was synthesized according to the standard reaction process, and separated and purified by silica gel column chromatography, using 100:1 petroleum ether and ethyl acetate as eluent. The product was a white solid, 14.18 mg, with a yield of 21%. The structural analysis data are as follows: 1 H NMR (400MHz, Chloroform-d) δ7.43(m,2H),7.34(m,3H),7.24–7.20(m,4H),7.09(m,3H),7.02–6.96(m,3H),2.22(s,3H). 13 C NMR(101MHz,Chloroform-d)δ145.00, 144.50,144.03,140.32,136.66,131.80,130.95,130.25,129.08,128.81,128.37,127.54,127.16,126.77,24.31.

[0094] prop-1-ene-1,1,2,3-tetrayltetrabenzene(l):

[0095]

[0096] The product was synthesized according to the standard reaction process, and separated and purified by silica gel column chromatography, using 100:1 petroleum ether and ethyl acetate as eluent. The product was a white solid, 14.18 mg, with a yield of 28%. The structural analysis data are as follows: 1 H NMR (400MHz, Chloroform-d) δ7.32(s,1H),7.24–7.18(m,1H),7.14(d,J=7.3 Hz,1H),7.07(m,3H),6.98(d,J=7.3Hz,1H),3.92(s,1H),1.28(s,2H). 13C NMR (101MHz,Chloroform-d)δ144.11,143.82,143.07,142.61,141.06,138.95,131.71,130.92,130.44,129.71,129.22,129.11,128.66,128.44,127.84,127.19,126.98,126.70, 42.41。

Claims

1. A method for synthesizing tri-substituted and tetra-substituted olefins by alkylation of non-terminal olefins, characterized in that: A non-terminal olefin of formula 1 and a sulfoxide of formula 2 are reacted in one pot in the presence of ferric chloride and hydrogen peroxide, wherein a hydrogen atom on the terminal carbon of the olefin is replaced by the R group in the sulfoxide to obtain a trisubstituted olefin or a tetrasubstituted olefin of formula 3; The non-terminal olefin has a structure of Formula 1: Formula 1 The sulfoxide has a structure of Formula 2: Formula 2 The tri-substituted olefin or the tetra-substituted olefin has a structure of Formula 3: Formula 3 in, R is methyl, ethyl, phenyl or benzyl; R1 or R2 is C1~C 10 alkyl, or hydrogen, fluorine, chlorine, bromine, iodine, cyano, carboxyl, ester or nitro, and R1 and R2 cannot be hydrogen at the same time; R3 is C1~C 10 or a fluorine, chlorine, bromine, iodine, cyano, carboxyl, ester or nitro group.

2. A method for synthesizing tri-substituted and tetra-substituted olefins by alkylation of non-terminal olefins according to claim 1, characterized in that: The ratio of hydrogen peroxide to non-terminal olefin is 2~8:

1.

3. A method for synthesizing tri-substituted and tetra-substituted olefins by alkylation of non-terminal olefins according to claim 2, characterized in that: The ratio of hydrogen peroxide to non-terminal olefin is 4:

1.

4. A method for synthesizing tri-substituted and tetra-substituted olefins by alkylation of non-terminal olefins according to claim 1, characterized in that: The reaction temperature is 80~160℃.

5. A method for synthesizing tri-substituted and tetra-substituted olefins by alkylation of non-terminal olefins according to claim 4, characterized in that: The reaction temperature was 140°C.

6. A method for synthesizing tri-substituted and tetra-substituted olefins by alkylation of non-terminal olefins according to claim 1, characterized in that: The reaction conditions are: in an atmospheric atmosphere, at a temperature of 80-160°C, for 2-12 hours.

7. A method for synthesizing tri-substituted and tetra-substituted olefins by alkylation of non-terminal olefins according to claim 6, characterized in that: The reaction conditions are: in an atmospheric atmosphere, at a temperature of 140°C, for 6 hours.

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