A method for preparing α,β-unsaturated acyl silicon

Abstract

The invention discloses a method for synthesizing α,β-unsaturated acyl silicon by ruthenium catalysis, and belongs to the technical field of organic chemistry. Olefin 1 and simple acyl silicon 2 are used as raw materials, and react in an organic solvent in the presence of a ruthenium catalyst to efficiently obtain α,β-unsaturated acyl silicon 3-5 in one step. The method has the advantages of simple operation, high yield, high product quality, and a wide range of substrate applications. A series of α,β-unsaturated acyl silicon compounds can be obtained by using the method.

Description

Technical Field

[0001] The invention belongs to the technical field of organic chemistry, and specifically relates to a method for preparing α,β-unsaturated acyl silicon by ruthenium catalysis. Background Art

[0002] In organic synthesis, acyl silicon is a very important molecular building block. Due to its special properties (photochemical properties / silicon positive charge), it has attracted widespread attention. For example, the photochemical properties of acyl silicon are used to modify sugars and polymer derivatives; the positive charge of acyl silicon can also be used to efficiently and quickly synthesize a series of amide compounds. It can be seen that in organic synthesis, acyl silicon is a class of reagents with potential application value.

[0003] At present, the synthesis method of α,β-unsaturated acyl silicon is a protection-silylation-deprotection strategy, but this method has great drawbacks. First, the selected lithium silicon reagent is difficult to prepare and is unstable; second, the reaction conditions are harsh and require an anhydrous and oxygen-free environment, which increases the complexity of the experimental operation; more importantly, this method is only applicable to the synthesis of β-aryl substituted unsaturated acyl silicon, but cannot be used to synthesize β-aryl substituted unsaturated acyl silicon. For example: in the synthesis of β-n-hexyl-α,β-unsaturated unsaturated acyl silicon, the first few steps of the reaction can proceed normally, but in the end only a complex mixture can be obtained, and the target product cannot be separated smoothly. The reaction equation is expressed as follows:

[0004]

[0005] In recent years, a method for preparing α,β-unsaturated acyl silicon compounds by rhenium-catalyzed rearrangement of alkynols has made important breakthroughs. This method can be used to synthesize β-aryl / alkenyl / alkynyl substituted unsaturated acyl silicon, but it is still not applicable to β-alkyl substituted unsaturated acyl silicon. The reaction equation is as follows:

[0006]

[0007] This route achieves efficient synthesis of α,β-unsaturated acyl silicon, but it has great limitations for alkane α,β-unsaturated acyl silicon products. At the same time, the use of transition metal tetrabutylrhenium oxide as a catalyst in the reaction process has the disadvantages of high cost, the need for an inert gas environment, and the inability to prepare in large quantities.

[0008] Therefore, it is very important to develop a simple, efficient and universal method for synthesizing α,β-unsaturated acyl silicon. Summary of the invention

[0009] In view of this, the present invention provides a method for preparing α,β-unsaturated acyl silicon by ruthenium catalysis. At room temperature and under ruthenium catalysis conditions, α,β-unsaturated acyl silicon can be synthesized in one step by simply adding an olefin reagent. This method avoids the shortcomings of the traditional preparation method, such as cumbersome reaction steps, harsh reaction conditions, limited substrate range, and complicated operation. The method can efficiently obtain α,β-unsaturated acyl silicon.

[0010] The method for synthesizing α,β-unsaturated acyl silicon of the present invention comprises the following steps: using olefin 1 and simple acyl silicon 2 as raw materials, reacting in an organic solvent in the presence of a ruthenium catalyst to obtain α,β-unsaturated acyl silicon 3-5. The reaction equation is as follows:

[0011]

[0012] Wherein: R is selected from phenethyl, benzyl, substituted benzyl, cyclohexyl, C8-10 alkyl, C2-C10 alkyl substituted with halogen, aldehyde, hydroxyl, silyl ether or ester, phenyl, substituted phenyl, The substituents in the substituted benzyl or phenyl groups are one or more of halogen, hydroxyl, and C1-C4 alkoxy.

[0013] Furthermore, in the above technical solution, the organic solvent is selected from dichloromethane, chloroform or 1,2-dichloroethane.

[0014] Furthermore, in the above technical solution, the ruthenium catalyst is selected from HG-II, and the specific structure is

[0015] Furthermore, in the above technical solution, the Si is selected from trimethylsilane (TMS), dimethyl tert-butylsilane (TBS) or dimethylphenylsilane (DMPS).

[0016] Furthermore, in the above technical solution, the molar ratio of the olefin 1, acyl silicon 2 and ruthenium catalyst is 1-2:1:0.05-0.075.

[0017] Advantageous Effects of the Invention

[0018] 1. The present invention is simple to operate. It only needs to add substrate olefin, acyl silicon and catalyst into the solvent. No other reagents or complicated reaction flow are required during the synthesis process. The process operation is simple.

[0019] 2. The olefins and catalyst reagents required in the reaction process of the present invention are easily available, and most of them can be purchased directly; less three wastes are generated in the reaction process, the environmental pollution is small, and the process has the potential for large-scale synthesis. DETAILED DESCRIPTION

[0020] The present invention is further described in detail below in conjunction with a specific implementation case. This implementation case is implemented on the premise of the technical solution of the present invention, and a detailed implementation method and a specific operation process are given, but the protection scope of the present invention is not limited to the following implementation case.

[0021] Example 1

[0022] Taking the synthesis of (E)-5-phenyl-2-pentenoyltrimethylsilane (3a), (E)-5-phenyl-2-pentenoyltert-butyldimethylsilane (4a), and (E)-5-phenyl-2-pentenoylphenyldimethylsilane (5a) from 4-phenyl-1-butene (1a) as an example, the reaction conditions were optimized as follows:

[0023]

[0024] After screening the conditions, the optimal conditions for synthesizing α,β-unsaturated acyl silicon were screened out as label 7: using 2.0eq olefin and tert-butyldimethylsilane (TBS) as the silicon source in the solvent and reacting at room temperature for 10h. The typical operation steps are as follows:

[0025] A: Preparation of (E)-5-phenyl-2-pentenoyltrimethylsilane (3a)

[0026] In a glove box, 4-phenyl-1-butene 1a (26 mg, 0.2 mmol), (1-oxy-2-propenyl)trimethylsilane 2a-1 (13 mg, 0.1 mmol), HG-II (4.6 mg) and 1 mL of dichloromethane were added and stirred at room temperature for 10 h. After distillation under reduced pressure to remove dichloromethane, the product 3a was separated and purified by column chromatography with a yield of 56%. 1 H NMR (400MHz, CDCl3) δ7.30 (dd, J=10.0, 4.6Hz, 2H), 7.20 (dd, J=12.9, 7.1Hz, 3H), 6.73 (dt, J=16.2, 6.8Hz,1H),6.22(dt,J=16.2,1.4Hz,1H),2.81(t,J=7.6Hz,2H),2.57(q,J=6.9Hz,2H),0.21(s,9H). 13C NMR (101MHz,CDCl3)δ236.87,147.55,140.81,136.98,128.60(d,J=10.7Hz),126.38,34.63(d,J=11.5Hz),-1.84.Nuclear magnetic data analysis: chemical shift 7.30, dd peak, attributed to two hydrogens of phenyl; chemical shift 7.20, dd peak, attributed to three other hydrogens of phenyl; chemical shift 6.73, dt peak, attributed to one hydrogen of olefin, chemical shift 6.22, dt peak, attributed to another hydrogen of olefin, chemical shift δ2.81, triplet, attributed to two hydrogens of methylene, chemical shift 2.57, triplet, attributed to another Two hydrogen atoms in methylene, chemical shift 0.21, single peak, attributed to 9 hydrogen atoms on silicon atom; chemical shift 236.87, single peak, attributed to one carbon atom on carbonyl; chemical shift 147.55, single peak, attributed to one carbon atom in phenyl group; chemical shift 140.81, single peak, attributed to another carbon atom in phenyl group; chemical shift 136.98, single peak, attributed to another carbon atom in phenyl group; chemical shift 128.60, double peak, attributed to one carbon atom in phenyl group and one carbon atom in olefin group; chemical shift 126.38, single peak, attributed to another carbon atom in olefin group; chemical shift 34.63 (d, J=11.5Hz), double peak, attributed to two methylene atoms; chemical shift -1.84, single peak, attributed to three carbon atoms in silicon atom. HRMS: m / z calc.for C 14 H 21 OSi[M+H] + ,233.1356;found,233.1355.Based on the above NMR and mass spectrometry test results, it was determined that the product was (E)-5-phenyl-2-pentenoyltrimethylsilane (3a).

[0027] B: Preparation of (E)-5-phenyl-2-pentenoyl tert-butyldimethylsilane (4a)

[0028] In a glove box, 4-phenyl-1-butene 1a (26 mg, 0.2 mmol), (1-oxy-2-propenyl) tert-butyldimethylsilane 2a-2 (13 mg, 0.1 mmol), HG-II (4.6 mg) and 1 mL of dichloromethane were added and stirred at room temperature for 10 h. After distillation under reduced pressure to remove dichloromethane, the product 4a was separated and purified by column chromatography with a yield of 70%. 1H NMR(400MHz, CDCl3)δ7.32(d,J=7.3Hz,2H),7.21(t,J=9.4Hz,3H),6.73–6.63(m,1H),6.37(d, J=15.9Hz,1H),2.81(t,J=7.6Hz,2H),2.57(dd,J=14.5,7.3Hz,2H),0.92(s,9H),0.21(s,6H). 13 C NMR (101MHz, CDCl3) δ235.87(s), 145.27(s), 140.87(s), 136.94(s), 128.58(d, J=1 0.2Hz),126.33(s),34.65(s),34.37(s),26.72(s),16.76(s),-5.89(s).HRMS:m / z calc.forC 17 H 26 OSiNa[M+Na] + ,297.1645;found,297.1655.

[0029] C: Preparation of (E)-5-phenyl-2-pentenoylphenyldimethylsilane (5a)

[0030] In a glove box, 4-phenyl-1-butene 1a (26 mg, 0.2 mmol), (1-oxy-2-propenyl)dimethylphenylsilane 2a-3 (13 mg, 0.1 mmol), HG-II (4.6 mg) and 1 mL of dichloromethane were added and stirred at room temperature for 10 h. After distillation under reduced pressure to remove dichloromethane, the product 5a was separated and purified by column chromatography with a yield of 62%. 1 H NMR (400MHz, CDCl3) δ7.52(d,J=7.0Hz,2H),7.46–7.35(m,3H),7.28(t,J=7.3Hz,2H),7.21(t,J=7.2Hz,1H),7.09(d,J=7. 4Hz,2H),6.65(dt,J=16.0,6.8Hz,1H),6.21(d,J=16.1Hz,1H),2.69(t,J=7.5Hz,2H),2.48(q,J=7.3Hz,2H),0.50(s,6H). 13 C NMR (101MHz, CDCl3) δ234.67,148.74,140.73,136.87,135.71,134.10,129.88,128.80–128.20(m),126.30,34.50(d,J=5.5Hz),-3.43.HRMS:m / z calc.for C 19H 22 OSiNa[M+Na] + ,317.1332;found,317.1333.

[0031] Example 2

[0032] According to the typical operation in Example 1 above, after replacing other reaction substrates, the reaction results are as follows:

[0033]

[0034] Representative product characterization data are as follows:

[0035] (E)-3-Phenylprop-2-enoyl tert-butyldimethylsilyl (4d): 1 H NMR (400MHz, CDCl3) δ7.56(dd,J=6.6,2.9Hz,2H),7.41–7.38(m,3H),7.36(d,J=8.7Hz,1H),7.02(d,J=16.2Hz,1H),0.98(s,9H),0.30(s,6H). 13 C NMR(101MHz, CDCl3)δ235.46,140.77,135.11,131.18,130.52,129.06,128.48,26.77,16.94,-5.97.HRMS(ESI):m / z calc.for[M+Na] + ,C 20 H 30 O2SiNa,353.1907; found,353.1916.

[0036] (E)-3-(4-Chloro-phenyl)prop-2-enoyl tert-butyldimethylsilyl (4f): 1 H NMR (400M Hz, CDCl3) δ7.43(d,J=8.2Hz,2H),7.31(d,J=8.1Hz,2H),7.21(d,J=5.5Hz,1H),6.94(d,J=16.1Hz,1H),0.91(s,9H),0.24(s,6H). 13 C NMR(101MHz, CDCl3)δ235.33,138.88,136.40,133.62,131.14,129.63,129.35,26.75,16.95,-6.07.HRMS(ESI):m / z calc.for[M+H] + ,C 15 H 22ClOSi,281.1123; found,281.1122.

[0037] (E)-2-Tridecenoyl tert-butyldimethylsilyl (41): 1 H NMR (400MHz, CDCl3) δ6.66 (dt, J=15.8, 6.9Hz, 1H), 6.34 (d, J=15.9Hz, 1H), 2.20 (td, J=8.0, 1.1H z, 2H), 1.48–1.42 (m, 2H), 1.28–1.26 (m, = 14H), 0.92 (s, 9H), 0.87 (t, J = 6.8Hz, 3H), 0.22 (s, 6H). 13 C NMR (101MHz, CDCl3) δ235.82,147.04,136.65,32.78,32.04,29.71,29.67,29.52,29.45,29.32,28.36,26.75,22.82,16.76,14.25,-5.80 . HRMS(ESI):m / z calc.for[M+H] + ,C 19 H 39 OSiNa,311.2765; found,311.2762.

[0038] (E)-9-Bromo-2-nonenoylphenyldimethylsilane (5m): 1 H NMR (400MHz, CDCl3) δ7.54(dd,J=7.4,1.9Hz,2H),7.43–7.34(m,3H),6.59(dt,J=16.1,6.9Hz,1H),6.18(d,J=16.1,1H ),3.37(t,J=6.8Hz,2H),2.13(q,J=5.9Hz,2H),1.85–1.74(m,2H),1.42–1.30(m,4H),1.25–1.15(m,2H),0.51(s,6H). 13 C NMR(101MHz, CDCl3)δ234.65),149.96,136.60,135.89,134.08,129.87,128.29, 33.88,32.71,32.64,28.20,27.97,27.94,-3.42.HRMS(ESI):m / zcalc.for[M+Na] + ,C 17 H 25 BrOSiNa,375.0750; found,375.0753.

[0039] (E)-12-aldehyde-2-dodecenoyltrimethylsilyl (3n): 1 H NMR (400MHz, CDCl3) δ9.76(t,J=1.8Hz,1H),6.74(dt,J=16.1,6.8Hz,1H),6.21(d,J=16.2,1H),2.42(td,J=7.3 ,1.8Hz,2H),2.26–2.20(m,2H),1.65–1.59(m,2H),1.50–1.44(m,2H),1.31(d,J=2.7Hz,8H),0.26–0.23(m,9H). 13 C NMR (101MHz, CDCl3) δ236.88,202.94,149.00,136.61,44.02,32.89,29.36,29.29,29.23,28.27,22.18,-1.77.HRMS(ESI):m / z calc.for[M+H] + ,C 15 H 29 O2Si,269.1931; found,269.1930.

[0040] (E)-Indole-2-carboxylic acid (7-hept-2-enoyl tert-butyldimethylsilyl) ester (4r): 1 H NMR (400MHz, CDCl3) δ9.17 (s, 1H), 7.69 (dd, J = 8.0, 0.5Hz, 1H), 7.44 (dd, J = 8.3 ,0.8Hz,1H),7.35–7.30(m,1H),7.25–7.21(m,1H),7.18–7.13(m,1H),6.68(dt ,J=15.9,6.8Hz,1H),6.44(d,J=15.9,1H),4.38(t,J=6.5Hz,2H),2.30(td,J=8 .0,1.2Hz,2H),1.86–1.79(m,2H),1.69–1.61(m,2H),0.93(s,9H),0.23(s,6H). 13 C NMR (101MHz, CDCl3) δ235.81,162.22,145.32,137.10,136.69,127.59,127.40,125.53,122. 70,120.95,112.07,108.88,64.71,32.18,28.41,26.71,24.81,16.77,-5.91.HRMS(ESI):m / z calc.for[M+Na] + ,C 22H 31 NO3SiNa,408.1965; found,408.1964.

[0041] The above are only preferred embodiments of the present invention. It should be noted that the above preferred embodiments should not be regarded as limiting the present invention, and the protection scope of the present invention should be based on the scope defined by the claims. For ordinary technicians in this technical field, several improvements and modifications can be made without departing from the spirit and scope of the present invention, and these improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A method for synthesizing α,β-unsaturated acyl silicon, characterized in that: The method comprises the following steps: using olefin 1 and simple acyl silicon 2 as raw materials, reacting in an organic solvent in the presence of a ruthenium catalyst HG-II to obtain α,β-unsaturated acyl silicon 3-5. The reaction equation is as follows: Wherein: R is selected from phenethyl, benzyl, substituted benzyl, cyclohexyl, C8-10 alkyl, C2-C10 alkyl substituted with halogen, aldehyde, hydroxyl, silyl ether or ester, phenyl, substituted phenyl, The substituent in the substituted benzyl or phenyl group is one or more of halogen, hydroxyl, and C1-C4 alkoxy, and the Si is selected from trimethylsilyl, dimethyl tert-butylsilyl or dimethylphenylsilyl.

2. The synthesis method according to claim 1, characterized in that: The organic solvent is selected from dichloromethane, chloroform or 1,2-dichloroethane.

3. The synthesis method according to claim 1, characterized in that: The molar ratio of the olefin 1, acyl silicon 2 and ruthenium catalyst is 1-2:1:0.05-0.075.

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