Novel method for electrochemically promoting synthesis of carbon-sulfur bonds

Abstract

The invention relates to a novel method for electrochemically promoting synthesis of carbon-sulfur bonds. Organic sulfur compounds are important targets in medicine and biology, and are also important intermediates in organic synthesis. Therefore, the synthesis of the compound has very important theoretical and application values. In an organic reaction constructed by a C-S bond, the organic sulfide is synthesized in one step by utilizing functionalization of olefin, and great interest of chemical families is aroused due to simple steps and relatively high atom economy. At present, development of construction of a C-S bond through an olefin functionalization reaction which is more efficient, green and free of transition metal participation becomes a target pursued by chemical families. According to the novel method provided by the invention, carbon-sulfur bonds can be well constructed, so that more required compounds can be synthesized.

Description

Technical Field

[0001] The invention belongs to the technical field of organic compound synthesis and is a new method for electrochemically promoting carbon-sulfur bond synthesis. Background Art

[0002] Sulfur-containing compounds are widely present in various drug molecules, natural products and molecules with life activities, so the construction of C-S bonds has become a very important direction in the field of organic synthesis. Electrochemical synthesis is considered to be the next breakthrough in green chemistry. In recent years, electrochemical synthesis has demonstrated its huge synthetic potential in reactions such as oxidative dehydrogenation, coupling and ring-closure reactions.

[0003] Literature research and our previous research work show that photochemically catalyzed defluorination cross-coupling of thiol-containing gem difluoroolefins can construct carbon-sulfur bonds [Junlei Wang, Binbin Huang, Chao Yang and Wujiong Xia. Chem. Commun. 2019, 55, 11103.]. However, this type of reaction has the following disadvantages: 1) The reaction time is extremely long, exceeding 24 hours. 2) Additional catalysts and alkaline additives are required.

[0004] Therefore, constructing a new, efficient and green method for synthesizing carbon-sulfur bonds has important academic and practical significance. Summary of the invention

[0005] The purpose of this section is to summarize some aspects of embodiments of the present invention and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the specification abstract and the invention title of this application to avoid blurring the purpose of this section, the specification abstract and the invention title, and such simplifications or omissions cannot be used to limit the scope of the present invention.

[0006] In view of the above problems and / or the problems existing in the prior art, the present invention is proposed.

[0007] Therefore, the purpose of the present invention is to overcome the deficiencies in the prior art and provide a new method for electrochemically promoting carbon-sulfur bond synthesis.

[0008] In order to solve the above technical problems, the present invention provides the following technical solutions: a new method for electrochemically promoting carbon-sulfur bond synthesis, comprising:

[0009] The carbon-sulfur bond is synthesized through an electrocatalytic coupling reaction, and a carbon-sulfur bond substrate is obtained by the reaction.

[0010] The new electrochemical method for promoting carbon-sulfur bond synthesis of the present invention is characterized in that the electrolyte used is nBu4NBr, and its usage amount is 100% of the geminal difluoroolefin.

[0011] The new electrochemical method for promoting carbon-sulfur bond synthesis described in the present invention is characterized in that the battery workstation used maintains a current of 6 mA.

[0012] The new electrochemical method for promoting carbon-sulfur bond synthesis described in the present invention is characterized in that various carbon-sulfur bond synthesis products are obtained by electrochemically catalyzing the reaction of various aromatic sulfurs, alkyl sulfurs and β-phenyl-substituted geminal difluoro olefin compounds.

[0013] The new method for electrochemically promoting carbon-sulfur bond synthesis described in the present invention is characterized in that: the new method for electrochemically promoting carbon-sulfur bond synthesis is characterized in that: the aromatic sulfurs and alkyl sulfurs are both commercially available aromatic sulfurs and alkyl sulfurs.

[0014] The new electrochemical method for promoting carbon-sulfur bond synthesis of the present invention is characterized in that the β-phenyl-substituted geminal difluoroolefin can be obtained by reacting aldehyde, triphenylphosphine and sodium 2-chloro-2,2-difluoroacetate.

[0015] Beneficial effects of the present invention:

[0016] The invention is simple and easy to operate, and the substances required in the method are low in toxicity, safe and environmentally friendly, have a wide range of subsequent transformations, high yields, and high reaction efficiency. In addition, the raw materials used in the invention are commercially available, and a carbon-sulfur bond synthesis substrate can be obtained through a series of reactions under mild conditions, and a variety of subsequent transformations can be performed. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative labor. Among them:

[0018] Figure 1 This is the hydrogen nuclear magnetic resonance spectrum of the product prepared in Example 1 of the present invention;

[0019] Figure 2 The NMR fluorine spectrum of the product prepared in Example 1 of the present invention;

[0020] Figure 3 The carbon NMR spectrum of the product prepared in Example 1 of the present invention; DETAILED DESCRIPTION

[0021] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the embodiments of the specification.

[0022] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0023] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive with other embodiments.

[0024] Example 1

[0025] The synthesis of tetra-tert-butylthiophenol substituted 1-(2,2-difluorovinyl)-4-methoxybenzene is as follows:

[0026] A stirring bar was placed in a 10 ml reaction bottle, and 0.1 mmol of 1-(2,2-difluorovinyl)-4-methoxybenzene, 1 eq n Bu4NBr and 3eq tetra-tert-butylbenzenethiol were added into the bottle, magnesium was used as the anode and platinum was used as the cathode. The current was maintained at 6 mA. Under nitrogen protection, 5 ml of MeCN was added into the reaction bottle and stirred for 3 h.

[0027] The product was characterized: Z-isomer: 1H NMR (600 MHz, CDCl3): δ7.53 (d, J = 8.6 Hz, 2H), 7.33-7.37 (m, 4H), 6.88 (d, J = 8.6 Hz, 2H), 6.71 (d, J = 16.3 Hz, 1H), 3.81 (s, 3H), 1.30 (s, 9H). Z isomer: 13C{1H}NMR (151MHz, CDCl3): δ159.3, 151.3 (d, J=293.7Hz), 150.9, 130.1 (d, J=3.1Hz), 129.6, 127.9, 1 26.4, 124.8, 118.2 (d, J = 32.2Hz), 113.9, 55.3, 34.6, 31.2.E-isomer: 6.24 (d, J = 32.6Hz, 1H). Both-isomers: 19F NMR (565MHz, CDCl3): δ-82.1 (d, J=16.3Hz), -88.1 (d, J=32.6Hz).

[0028] The product structure is:

[0029]

[0030] Example 2

[0031] The synthesis of tetra-tert-butylthiophenol substituted 2-(2,2-difluorovinyl)naphthalene is as follows:

[0032] A stirring bar was placed in a 10 ml reaction bottle, and 0.1 mmol of 2-(2,2-difluorovinyl)naphthalene, 1 eq nBu4NBr and 3 eq tetra-tert-butylbenzenethiol were added into the bottle. Magnesium was used as the anode and platinum as the cathode. The current was maintained at 6 mA. Under nitrogen protection, 5 ml of MeCN was added into the reaction bottle and stirred for 3 h.

[0033] The product was characterized: Z isomer: 1H NMR (600 MHz, CDCl3): δ 7.96 (s, 1H), 7.80-7.83 (m, 4H), 7.48 (t, J = 3.9, 2H), 7.43 (d, J = 8.5 Hz, 2H), 7.37 (d, J = 8.5 Hz, 2H), 6.89 (d, J = 16.4 Hz, 1H), 1.31 (s, 9H). Z isomer: 13C{1H}NMR (151MHz, CDCl3): δ153.2 (d, J=296.8Hz), 151.2, 133.3, 132.8, 130.2, 130.0 (d, J=8.8Hz), 128.4 (d, J=3.9Hz), 1 28.1, 127.9, 127.6, 127.4, 126.5, 126.3 (d, J=2.3Hz), 126.3, 118.0 (d, J=32.0Hz), 34.6, 31.2.Eisomer: 6.43 (d, J=32.6Hz, 1H).Both isomers: 19F NMR (565MHz, CDCl3): δ-79.5 (d, J=16.3Hz), -85.1 (d, J=32.4Hz).

[0034] The product structure is:

[0035]

[0036] Example 3

[0037] The synthesis of p-methylthiophenol-substituted 1-(2,2-difluorovinyl)-4-methoxybenzene is as follows:

[0038] A stirring bar was placed in a 10 ml reaction bottle, and 0.1 mmol of 1-(2,2-difluorovinyl)-4-methoxybenzene, 1 eq n Bu4NBr and 3eq p-methylthiophenol were added into the bottle, magnesium was used as the anode and platinum was used as the cathode. The current was maintained at 6 mA. Under nitrogen protection, 5 ml of MeCN was added into the reaction bottle and stirred for 3 h.

[0039] The product was characterized: Z isomer: 1H NMR (600 MHz, CDCl3): δ 7.55 (d, J = 8.7 Hz, 2H), 7.36 (d, J = 8.1 Hz, 2H), 7.16 (d, J = 7.9 Hz, 2H), 6.91 (d, J = 8.8 Hz, 2H), 6.72 (d, J = 16.4 Hz, 1H), 3.84 (s, 3H), 2.36 (s, 3H). Z isomer: 13C{1H}NMR (151MHz, CDCl3): δ159.3, 151.4 (d, J=293.2Hz), 137.8, 130.3, 13 0.1 (d, J=3.5Hz), 127.7, 124.8 (d, J=8.7Hz), 117.9 (d, J=32.4Hz), 113.9, 55.3, 21.1.E isomer: 6.25 (d, J=32.7Hz, 1H). Both isomers: 19F NMR (565MHz, CDCl3): δ-82.5 (d, J=16.3Hz), -88.5 (d, J=32.7Hz).

[0040] The product structure is:

[0041]

[0042] Example 4

[0043] The synthesis of 1-(2,2-difluorovinyl)-4-methoxybenzene substituted by fluorobenzenethiophenol is as follows:

[0044] A stirring bar was placed in a 10 ml reaction bottle, and 0.1 mmol of 1-(2,2-difluorovinyl)-4-methoxybenzene, 1 eq n Bu4NBr and 3eq p-methylthiophenol were added into the bottle, magnesium was used as the anode and platinum was used as the cathode. The current was maintained at 6 mA. Under nitrogen protection, 5 ml of MeCN was added into the reaction bottle and stirred for 3 h.

[0045] The product was characterized: Z isomer: 1H NMR (600 MHz, CDCl3): δ 7.50 (d, J = 8.6 Hz, 2H), 7.41-7.43 (m, 2H), 7.03 (t, J = 8.7 Hz, 2H), 6.89 (d, J = 8.6 Hz, 2H), 6.69 (d, J = 16.4 Hz, 1H), 3.82 (s, 3H). Z isomer: 13C{1H}NMR (151MHz, CDCl3): δ162.6 (d, J=247.8Hz), 159.4, 132.4 (d, J=8.3Hz), 131.3 (d, J=8.6Hz), 130.1 (d, J=3.2Hz), 125.4 (d, J=266.3Hz), 118.0 (d, J=32.0Hz), 116.5 (d, J=22.3Hz), 116.3 (d, J=21.9Hz), 113.9, 55.3.E isomer: 1H NMR (600MHz, CDCl3): δ6.23 (d, J=32.6Hz, 1H). Both isomers: 19F NMR (565MHz, CDCl3): δ-83.2 (d, J=16.4Hz), -89.0 (d, J=32.5Hz), -113.5-113.9 (m).

[0046] The product structure is:

[0047]

Claims

1. A new method for electrochemically promoting carbon-sulfur bond synthesis, comprising: The purpose is to promote the synthesis of carbon-sulfur bonds through electrocatalytic coupling reactions to obtain carbon-sulfur bond substrates.

2. The novel method for electrochemically promoting carbon-sulfur bond synthesis as claimed in claim 1, characterized in that: The electrolyte used was n Bu4NBr is used in an amount of 100% of the geminal difluoroolefin.

3. The novel electrochemical method for carbon-sulfur bond synthesis as claimed in claim 1, characterized in that: The battery workstation used maintained the current at 6 mA.

4. The novel method for electrochemically promoting carbon-sulfur bond synthesis as claimed in claim 1, characterized in that: Various carbon-sulfur bond synthesis products are obtained by electrochemically catalyzing the reaction of various aromatic sulfurs, alkyl sulfurs and β-phenyl-substituted geminal difluoro olefin compounds.

5. The novel method for electrochemically promoting carbon-sulfur bond synthesis as claimed in claim 1, characterized in that: The aryl sulfurs and alkyl sulfurs are commercially available aryl sulfurs and alkyl sulfurs.

6. The novel method for electrochemically promoting carbon-sulfur bond synthesis as claimed in claim 1, characterized in that: The beta-phenyl substituted geminal difluoroolefin can be obtained by reacting aldehyde, triphenylphosphine and sodium 2-chloro-2,2-difluoroacetate.

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