English

• 1.   Introduction

  Thiazolines are privileged skeletons found in natural products and bioactive molecules, ^[1] as well as widely used chiral ligands in asymmetric synthesis.^[2] Thus, a variety of synthetic approaches have been developed for the synthesis of thiazoline derivatives.^[3] Among these methods, cyclization of β-aminothiols was the most generally used approach.^[4] Recently, intramolecular cyclization of N-allyl- thioamides was also utilized for the synthesis of thiazoline derivatives.^[5] Despite the achieved progress, these protocols usually required toxic reagents, expensive metal catalysts and harsh conditions, which also accompanied by limited substrate scope and waste formation. Therefore, developing a green and efficient protocol for the construction of functionalized thiazolines is still in high demand.

  Organoselenium compounds, as versatile synthetic intermediates, are widely used in organic synthesis.^[6] The selenium-containing heterocycles have attracted great attention in pharmaceutical agents.^[7] Therefore, continuous efforts have been explored to develop efficient protocols for the synthesis of these derivatives.^[8] In the last decade, the intramolecular difunctionalization of readily available alkenes with easily accessible diselenides has received broad attention, generating various selenium-containing heterocycles, such as oxazolines, ^[9] isoxazolines, ^[10] dihydrofurans, ^[11] and γ-lactams.^[12] However, to the best of our knowledge, a general synthetic method for the synthesis of selenium-containing thiazolines remains undeveloped.

  Due to environmentally benign and mild conditions, electrochemical reactions have been widely developed in recent years.^[13] Electrochemical synthesis provides a direct approach to generate radical intermediates, which could avoid toxic oxidants and minimize waste formation.^[14-15] Very recently, the electrochemical difunctionalization of alkenes with diselenides has been reported.^[16]

  Lei group^[17] explored a practical method for the synthesis of seleno oxazolines via electrochemical oxidative cyclization of N-allylamides (Scheme 1a). Sarkar group^[18] developed a tandem electrochemical cyclization process for the synthesis of isoxazolines (Scheme 1b). In view of the importance of seleno-containing heterocycles and our continued interest in thioamide chemistry, ^[19] we herein developed a general electrochemical oxidative cyclization process for the synthesis of seleno-containing thiazolines using easily accessible N-allylthioamides under air at room temperature (Scheme 1c). A series of seleno-containing thiazoline derivatives, including the trifluoromethyl substituted derivatives, were obtained in catalyst- and oxidant-free conditions.

  Scheme 1

  

  Scheme 1.  Electrochemical reactions based on diselenides

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  2.   Results and discussion

  The readily available N-allylbenzothioamide (1a) and 1, 2-diphenyldiselane (2a) were chosen as the model substrates (Table 1). Utilizing the cheap carbon felt as both anode and cathode in an undivided cell under constant current of 2 mA, the reaction proceeded well in the presence of LiClO₄ (1.5 equiv.) and CH₃CN (4 mL) to provide the desired product 3a in 68% yield (Entry 1). Encouraged by this result, a series of electrodes were tested and carbon felt was the best choice (Entries 1~4). Next, the electrolytes (Entries 5~8) and the solvents (Entries 9~12) were screened. The optimum electrolyte was LiClO₄ and the best solvent was CH₃CN. It was found that changing the reaction temperature did not improve the yields (Entries 13 and 14). A comparable yield was obtained under N₂ atmosphere (Entry 15). Notably, decreasing or increasing the constant current were found to be inferior for the reaction (Entries 16 and 17). No desired product was obtained in the absence of electricity (Entry 18). Finally, the optimized reaction conditions were defined as follows: carbon felt anode and cathode, 2 mA, 1a (0.2 mmol), 2a (0.6 equiv.), and LiClO₄ (1.5 equiv.) in CH₃CN (0.05 mol/L) at room temperature for 4 h.

  Table 1

  

  Table 1.  Optimization of reaction conditions^a

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  Entry	Anode/Cathode	Electrolyte	Solvent	Yieldb/%
  1	CF/CF	LiClO4	CH3CN	68
  2	Pt/C	LiClO4	CH3CN	49
  3	C/Pt	LiClO4	CH3CN	46
  4	C/C	LiClO4	CH3CN	53
  5	CF/CF	nBu4NBF4	CH3CN	15
  6	CF/CF	nBu4NI	CH3CN	0
  7	CF/CF	nBu4NPF6	CH3CN	23
  8	CF/CF	NH4ClO4	CH3CN	51
  9	CF/CF	LiClO4	CH3OH	60
  10	CF/CF	LiClO4	CH3CN/C2H5OH (V:V=1:1)	58
  11	CF/CF	LiClO4	DMF	0
  12	CF/CF	LiClO4	CH3CN/HFIP (V:V=1:1)	16
  13c	CF/CF	LiClO4	CH3CN	66
  14d	CF/CF	LiClO4	CH3CN	40
  15e	CF/CF	LiClO4	CH3CN	65
  16f	CF/CF	LiClO4	CH3CN	56
  17g	CF/CF	LiClO4	CH3CN	54
  18h	CF/CF	LiClO4	CH3CN	0
  a Reaction conditions: CF anode, CF cathode, 1a (0.2 mmol), 2a (0.6 equiv.), electrolyte (1.5 equiv), solvent (4 mL), 2 mA, under air, 4 h. b Isolated yields. c T=0 ℃. d T=50 ℃. e Under N2. f 1 mA, 10 h, g 3 mA. h No electric current.

  With the optimized reaction conditions in hand, the scope with respect to thioamides 1 was first examined (Table 2). The reactions proceeded soomthly with arylthioam- ides bearing electron-donating groups (Me, OMe, Ph) and electron-withdrawing groups (Cl, Br, COOMe, CF₃) at para-position, and the desired thiazolines 3a~3h were afforded in 48%~68% yields. Substrates with ortho- and meta-chloro groups generated the desired products 3i and 3j in 63% and 61% yields, respectively. In addition, the reaction with disubstituted thioamide 1k worked well to provide product 3k in 50% yield. The reaction was compatible with naphthylthioamide to generate product 3l in 60% yield. Heteroarylthioamides, such as furan and thiophene, were also tolerated to give the desired products 3m and 3n in 60% and 47% yields, respectively. It was noteworthy that cyclohexyl substrate was well tolerated to form product 3o in 53% yield.

  Table 2

  

  Table 2.  Scope of thioamides^{a, b}

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  a Reaction conditions: CF anode, CF cathode, 1 (0.2 mmol), 2a (0.6 equiv.), LiClO4 (1.5 equiv.), CH3CN (4 mL), 2 mA, 4 h. b Isolated yields.

  Next, the substrate scope of diselenides was tested under the optimized reaction conditions (Table 3). The reactions of diselenides bearing electron-donating groups at para- position run smoothly with thioamide 1a to obtain the desired products 3p and 3q in good yields. Electron- withdrawing chloro group on the phenyl ring was also tolerated, although product 3r was formed in low yield. For the reaction of diselenide with a naphthyl group, the desired product 3s was afforded in 60% yield. Heterocyclic substituted diselenide such as thiophene was also compatible in the reaction to give product 3t in 47% yield. Nota- bly, the reaction was found to be tolerant for alkyl substituted diselenides (Me, Bn, Cy), the corresponding products 3u~3w were isolated in moderate yields.

  Table 3

  

  Table 3.  Scope of the diselenides^{a, b}

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  a Reaction conditions: CF anode, CF cathode, 1a (0.2 mmol), 2 (0.6 equiv.), LiClO4 (1.5 equiv.), CH3CN (4 mL), 2 mA, 4 h. b Isolated yields.

  Incorporation of trifluoromethyl group into organic molecules is a broadly adopted strategy in drug design.^[20] The reactions of trifluoromethyl thioamides with different substituted diselenides such as phenyl, naphthyl and methyl proceeded smoothly to give products 4a~4c in high yields (Table 4). In addition, thioamides bearing 1, 1-di- substituted alkenes reacted successfully with diphenyl- diselane (2a) to produce the desired products 4d and 4e in 83% and 37% yields, respectively. Satisfyingly, substrate with trisubstituted alkene was also well tolerated, generating the desired product 4f in 53% yield. It is noteworthy to obtain products 4a~4f, and these trilfluoromethyl substituted derivatives might show potential bioactivity.

  Table 4

  

  Table 4.  Scope of the trifluoromethyl thioamides^{a, b}

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  a Reaction conditions: CF anode, CF cathode, 1 (0.2 mmol), 2 (0.6 equiv.), LiClO4 (1.5 equiv.), CH3CN (4 mL), 2 mA, 4 h. b Isolated yields. c Under N2, 8 h.

  Gram-scale reaction was performed in order to prove the practicality of this electrochemical process (Scheme 2, a). When 1a reacted with 2a under 10 mA constant current for 18 h, the desired product 3a was obtained in 1.25 g. To gain insight into the mechanism, control experiments were performed. Only trace amount of 3a was detected in the presence of 2, 2, 6, 6-tetramethylpiperidin-1-yloxyl (TEMPO), indicating the possibility of radical reaction pathway (Scheme 2, b). In addition, radical-clock experiment was explored using 1x as reactant, producing 3x in 54% yield with the cyclopropyl group retained (Scheme 2, c). This result excludes the intramolecular thiyl radical cyclization/ selenylation mechanism.^[5b] Furthermore, cyclic voltammetry (CV) experiments were also carried out to study the redox potential of the reactants. An obvious reduction peak of 2a is observed at -0.51 V, which implies that the reduction of 2a is a readily pathway.

  Scheme 2

  

  Scheme 2.  Gram-scale and control experiments

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  Based on the control experiments and literature reports, ^[15] a plausible reaction mechanism has been proposed in Scheme 3. First, diselenide 2a is reduced at the cathode to generate selenium radical A and selenium anion B.Intermediate B could be easily oxidized at the anode to form radical A. Subsequently, radical addition of intermediate A with 1a generates alkyl radical C, which is further oxidized at the anode to give carbocation D. Finally, regioselective intramolecular 5-exo-trig cyclization accompanied by deprotonation affords the desired product 3a.

  Scheme 3

  

  Scheme 3.  Possible mechanism

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  3.   Conclusions

  In conclusion, an efficient strategy for the construction of selenium-containing thiazolines by electrochemical selenylation/cyclization of N-allylthioamides has been developed. This green strategy is performed in catalyst- and oxidant-free conditions under air at room temperature. The reaction also features a broad substrate scope, easy operation and excellent selectivity. In addition, the selenyl thiazolines bearing trifluoromethyl group were also synthesized, which might exhibit potential biological activity.

  4.   Experimental section

  4.1   General information

  Column chromatography was performed on silica gel (200~300 mesh) using analytical pure ethyl acetate and petroleum ether. Melting points were recorded on a RY-1 microscopic melting apparatus and uncorrected. NMR spectra were recorded in DMSO-d₆ on 500 MHz spectrometers (500 MHz for ¹H NMR, 125 MHz for ¹³C NMR and 375 MHz for ¹⁹F NMR). Massspectra were obtained on an Ultima Global spetrometer with an ESI source. The electrochemical instrument is HONGSHENGFENG DPS- 305BM. All the reactions were carried out under an air atmosphere using glassware without being predried. Unless noted, all commercial reagents and solvents were used without further purification.

  4.2   General procedure

  To a 10 mL two-necked flask was added thioamide 1 (0.2 mmol), diselenides 2 (0.12 mmol, 0.6 equiv.), LiClO₄ (0.3 mmol, 1.5 equiv.) and CH₃CN (4 mL). The flask was equipped with a carbon felt anode (1.5 cm×1 cm×0.5 cm) and a carbon felt cathode (1.5 cm×1 cm×0.5 cm). The whole cell was undivided cell. The reaction mixture was electrolyzed at a constant current of 2 mA at room temperature for 4 h. After completion of the reaction [monitored by thin-layer chromatography (TLC)], the solvent was removed under vacuum. The residue was purified by column chromatography on silica gel, eluting with ethyl acetate/petroleum ether to give compound 3.

  2-Phenyl-5-((phenylselanyl)methyl)-4, 5-dihydrothiazole (3a): 45 mg, 68% yield, light yellow oil. R_f=0.4 [V(petroleum ether):V(ethyl acetate)=10:1]; ¹H NMR (DMSO-d₆, 500 MHz) δ: 7.74 (d, J=7.6 Hz, 2H), 7.48 (dt, J=28.3, 7.3 Hz, 5H), 7.33~7.22 (m, 3H), 4.42 (dd, J=16.3, 3.3 Hz, 1H), 4.30 (dd, J=16.3, 8.1 Hz, 1H), 4.22~4.14 (m, 1H), 3.18 (d, J=7.3 Hz, 2H); ¹³C NMR (DMSO- d₆, 125 MHz) δ: 165.5, 133.3, 132.4, 131.8, 129.8, 129.8, 129.2, 128.4, 127.5, 69.7, 51.3, 33.2; HRMS (ESI-TOF) calcd for C₁₆H₁₆NSSe [M+H]⁺ 334.0169, found 334.0170.

  5-((Phenylselanyl)methyl)-2-(p-tolyl)-4, 5-dihydro- thiazole (3b): 45 mg, 65% yield, light yellow oil. R_f=0.5 [V(petroleum ether):V(ethyl acetate)=10:1]; ¹H NMR (DMSO-d₆, 500 MHz) δ: 7.64~7.60 (m, 2H), 7.54~7.48 (m, 2H), 7.32~7.23 (m, 5H), 4.39 (dd, J=16.3, 3.6 Hz, 1H), 4.28 (dd, J=16.3, 8.0 Hz, 1H), 4.20~4.13 (m, 1H), 3.17 (d, J=7.3 Hz, 2H), 2.33 (s, 3H); ¹³C NMR (DMSO- d₆, 125 MHz) δ: 165.3, 141.8, 132.4, 130.6, 129.8, 129.8, 128.4, 127.5, 69.6, 51.2, 33.2, 21.5; HRMS (ESI-TOF) calcd for C₁₇H₁₈NSSe [M+H]⁺ 348.0325, found 348.0330.

  2-(4-Methoxyphenyl)-5-((phenylselanyl)methyl)-4, 5- dihydrothiazole (3c): 40 mg, 55% yield, light yellow oil. R_f=0.4 [V(petroleum ether):V(ethyl acetate)=5:1]; ¹H NMR (DMSO-d₆, 500 MHz) δ: 7.68 (d, J=8.6 Hz, 2H), 7.51 (d, J=6.9 Hz, 2H), 7.33~7.23 (m, 3H), 6.99 (d, J=8.6 Hz, 2H), 4.37 (dd, J=16.1, 3.5 Hz, 1H), 4.25 (dd, J=16.1, 8.0 Hz, 1H), 4.19~4.11 (m, 1H), 3.78 (s, 3H), 3.17 (d, J=7.3 Hz, 2H); ¹³C NMR (DMSO-d₆, 125 MHz) δ: 164.7, 162.1, 132.4, 130.1, 129.8, 127.5, 125.9, 114.5, 69.6, 55.9, 51.3, 33.2; HRMS (ESI-TOF) calcd for C₁₇H₁₈- NOSSe [M+H]⁺ 364.0274, found 364.0273.

  2-([1, 1'-Biphenyl]-4-yl)-5-((phenylselanyl)methyl)-4, 5- dihydrothiazole (3d): 39 mg, 48% yield, light yellow oil. R_f=0.4 [V(petroleum ether):V(ethyl acetate)=5:1]; ¹H NMR (DMSO-d₆, 500 MHz) δ: 7.86 (d, J=7.8 Hz, 2H), 7.80 (d, J=8.0 Hz, 2H), 7.74 (d, J=7.3 Hz, 2H), 7.57 (d, J=6.9 Hz, 2H), 7.51 (t, J=7.4 Hz, 2H), 7.44 (d, J=7.2 Hz, 1H), 7.37~7.26 (m, 3H), 4.48 (dd, J=16.4, 3.1 Hz, 1H), 4.36 (dd, J=16.4, 8.1 Hz, 1H), 4.28~4.21 (m, 1H), 3.24 (d, J=7.2 Hz, 2H); ¹³C NMR (DMSO-d₆, 125 MHz) δ: 165.1, 143.2, 139.4, 132.4, 132.2, 129.8, 129.5, 129.0, 128.6, 127.4, 127.4, 127.2, 69.7, 51.4, 33.1; HRMS (ESI- TOF) calcd for C₂₂H₂₀NSSe [M+H]⁺ 410.0482, found 410.0483.

  2-(4-Chlorophenyl)-5-((phenylselanyl)methyl)-4, 5- dihydrothiazole (3e): 46 mg, 63% yield, light yellow oil. R_f=0.4 [V(petroleum ether):V(ethyl acetate)=10:1]; ¹H NMR (DMSO-d₆, 500 MHz) δ: 7.76 (d, J=8.4 Hz, 2H), 7.55 (t, J=7.6 Hz, 4H), 7.35~7.25 (m, 3H), 4.44 (dd, J=16.4, 3.5 Hz, 1H), 4.32 (dd, J=16.4, 8.1 Hz, 1H), 4.27~4.21 (m, 1H), 3.22 (d, J=7.3 Hz, 2H); ¹³C NMR (DMSO-d₆, 125 MHz) δ: 164.0, 136.0, 131.9, 131.5, 129.6, 129.5, 129.3, 129.2, 128.8, 127.0, 69.2, 51.3, 32.6; HRMS (ESI-TOF) calcd for C₁₆H₁₅ClNSSe [M+H]⁺ 367.9779, found 367.9780.

  2-(4-Bromophenyl)-5-((phenylselanyl)methyl)-4, 5- dihydrothiazole (3f): 45 mg, 55% yield, light yellow oil. R_f=0.4 [V(petroleum ether):V(ethyl acetate)=10:1]; ¹H NMR (DMSO-d₆, 500 MHz) δ: 7.70 (s, 4H), 7.59~7.51 (m, 2H), 7.36~7.28 (m, 3H), 4.45 (dd, J=16.4, 3.5 Hz, 1H), 4.33 (dd, J=16.3, 8.1 Hz, 1H), 4.28~4.22 (m, 1H), 3.23 (d, J=7.3 Hz, 2H); ¹³C NMR (DMSO-d₆, 125 MHz) δ: 164.6, 132.4, 132.4, 132.3, 130.3, 129.8, 129.7, 127.5, 125.4, 69.7, 51.8, 33.1; HRMS (ESI-TOF) calcd for C₁₆H₁₅BrNSSe [M+H]⁺ 411.9274, found 411.9270.

  Methyl 4-(5-((phenylselanyl)methyl)-4, 5-dihydro- thiazol-2-yl)benzoate (3g): 38 mg, 49% yield, light yellow oil. R_f=0.4 [V(petroleum ether):V(ethyl acetate)=10:1]; ¹H NMR (DMSO-d₆, 500 MHz) δ: 8.02 (d, J=8.2 Hz, 2H), 7.86 (d, J=8.2 Hz, 2H), 7.52 (d, J=6.8 Hz, 2H), 7.32~7.24 (m, 3H), 4.46 (dd, J=16.6, 3.6 Hz, 1H), 4.33 (dd, J=16.6, 8.1 Hz, 1H), 4.27~4.20 (m, 1H), 3.85 (s, 3H), 3.20 (d, J=7.3 Hz, 2H); ¹³C NMR (DMSO-d₆, 125 MHz) δ: 166.0, 164.9, 137.1, 132.4, 132.3, 130.1, 129.8, 129.7, 128.7, 127.5, 69.8, 52.9, 51.7, 33.1; HRMS (ESI- TOF) calcd for C₁₈H₁₈NO₂Sse [M+H]⁺ 392.0223, found 392.0228.

  5-((Phenylselanyl)methyl)-2-(4-(trifluoromethyl)- phenyl)-4, 5-dihydrothiazole (3h): 52 mg, 65% yield, white solid. R_f=0.5 [V(petroleum ether):V(ethyl acetate)=10:1]; m.p. 49~51 ℃; ¹H NMR (DMSO-d₆, 500 MHz) δ: 7.97 (d, J=8.1 Hz, 2H), 7.86 (d, J=7.9 Hz, 2H), 7.56 (d, J=7.5 Hz, 2H), 7.37~7.26 (m, 3H), 4.51 (dd, J=16.6, 3.5 Hz, 1H), 4.39 (dd, J=16.5, 8.2 Hz, 1H), 4.34~4.25 (m, 1H), 3.25 (d, J=7.3 Hz, 2H); ¹³C NMR (DMSO-d₆, 125 MHz) δ: 164.6, 136.8, 132.4, 131.7, 131.4, 131.2, 129.8, 129.7, 129.1, 127.5, 126.2, 126.2, 124.3 (d, J=272.6 Hz), 69.8, 51.9, 33.0; ¹⁹F NMR (DMSO-d₆, 375 MHz) δ: -61.48; HRMS (ESI-TOF) calcd for C₁₇H₁₅F₃N- SSe [M+H]⁺ 402.0043, found 402.0041.

  2-(2-Chlorophenyl)-5-((phenylselanyl)methyl)-4, 5- dihydrothiazole (3i): 46 mg, 63% yield, light yellow oil. R_f=0.4 [V(petroleum ether):V(ethyl acetate)=10:1]; ¹H NMR (DMSO-d₆, 500 MHz) δ: 7.72 (d, J=7.6 Hz, 2H), 7.55~7.46 (m, 3H), 7.40 (t, J=7.6 Hz, 2H), 7.25 (q, J=5.5 Hz, 3H), 5.00~4.87 (m, 1H), 4.07 (dd, J=15.0, 9.6 Hz, 1H), 3.70 (dd, J=15.0, 6.9 Hz, 1H), 3.31~3.22 (m, 2H); ¹³C NMR (DMSO-d₆, 125 MHz) δ: 155.0, 146.4, 142.9, 132.2, 129.9, 129.7, 127.3, 114.7, 112.2, 78.9, 59.9, 31.4; HRMS (ESI-TOF) calcd for C₁₆H₁₅ClNSSe [M+H]⁺ 367.9779, found 367.9780.

  2-(3-Chlorophenyl)-5-((phenylselanyl)methyl)-4, 5- dihydrothiazole (3j): 45 mg, 61% yield, light yellow oil. R_f=0.5 [V(petroleum ether):V(ethyl acetate)=10:1]; ¹H NMR (DMSO-d₆, 500 MHz) δ: 7.78~7.47 (m, 6H), 7.41~7.16 (m, 3H), 4.46 (dt, J=16.8, 8.4 Hz, 1H), 4.38~4.18 (m, 2H), 3.22 (dd, J=14.4, 8.3 Hz, 2H); ¹³C NMR (DMSO-d₆, 125 MHz) δ: 164.3, 135.1, 134.0, 132.4, 131.7, 131.3, 129.8, 129.8, 127.5, 127.2, 69.7, 51.8, 33.0; HRMS (ESI-TOF) calcd for C₁₆H₁₅ClNSSe [M+H]⁺ 367.9779, found 367.9777.

  2-(2-Bromo-5-methoxyphenyl)-5-((phenylselanyl)- methyl)-4, 5-dihydrothiazole (3k): 44 mg, 50% yield, light yellow oil. R_f=0.2 [V(petroleum ether):V(ethyl acetate)=10:1]; ¹H NMR (DMSO-d₆, 500 MHz) δ: 7.61 (d, J=8.8 Hz, 1H), 7.56 (d, J=7.3 Hz, 2H), 7.33 (dt, J=12.2, 6.7 Hz, 3H), 7.09 (d, J=3.0 Hz, 1H), 7.02 (dd, J=8.8, 3.0 Hz, 1H), 4.50~4.43 (m, 1H), 4.26 (dd, J=11.6, 3.8 Hz, 2H), 3.79 (s, 3H), 3.28 (d, J=6.8 Hz, 2H); ¹³C NMR (DMSO- d₆, 125 MHz) δ: 164.5, 158.8, 136.1, 134.6, 132.3, 129.8, 129.7, 127.4, 118.1, 115.9, 110.9, 69.4, 56.1, 53.0, 32.8; HRMS (ESI-TOF) calcd for C₁₇H₁₇BrNOSSe [M+H]⁺ 441.9379, found 441.9374.

  2-(Naphthalen-1-yl)-5-((phenylselanyl)methyl)-4, 5- dihydrothiazole (3l): 46 mg, 60% yield, light yellow oil. R_f=0.3 [V(petroleum ether):V(ethyl acetate)=10:1]; ¹H NMR (DMSO-d₆, 500 MHz) δ: 8.79 (d, J=7.8 Hz, 1H), 8.08 (d, J=8.2 Hz, 1H), 8.02 (d, J=9.0 Hz, 1H), 7.80 (d, J=6.7 Hz, 1H), 7.65~7.57 (m, 5H), 7.34 (dt, J=12.1, 6.8 Hz, 3H), 4.65 (dd, J=16.3, 3.5 Hz, 1H), 4.52 (dd, J=16.3, 8.1 Hz, 1H), 4.32~4.21 (m, 1H), 3.33 (d, J=7.3 Hz, 2H); ¹³C NMR (DMSO-d₆, 125 MHz) δ: 165.2, 133.8, 132.4, 131.6, 130.5, 130.2, 129.9, 129.1, 128.9, 127.8, 127.5, 126.9, 126.1, 126.0, 125.5, 70.9, 51.1, 33.3; HRMS (ESI-TOF) calcd for C₂₀H₁₈NSSe [M+H]⁺ 384.0325, found 384.0325.

  2-(Furan-2-yl)-5-((phenylselanyl)methyl)-4, 5-dihydro- thiazole (3m): 39 mg, 60% yield, light yellow oil. R_f=0.3 [V(petroleum ether):V(ethyl acetate)=5:1]; ¹H NMR (DMSO-d₆, 500 MHz) δ: 7.9 (s, 1H), 7.5 (d, J=7.6 Hz, 2H), 7.4~7.3 (m, 3H), 7.0 (d, J=3.4 Hz, 1H), 6.7 (d, J=3.3 Hz, 1H), 4.4 (dd, J=16.2, 3.2 Hz, 1H), 4.3~4.1 (m, 2H), 3.2 (d, J=7.3 Hz, 2H); ¹³C NMR (DMSO-d₆, 125 MHz) δ: 155.1, 147.9, 146.3, 132.4, 129.8, 129.7, 127.5, 114.1, 112.7, 69.4, 51.2, 32.9; HRMS (ESI-TOF) calcd for C₁₄H₁₄NOSSe [M+H]⁺ 323.9961, found 323.9963.

  5-((Phenylselanyl)methyl)-2-(thiophen-2-yl)-4, 5- dihydrothiazole (3n): 32 mg, 47% yield, light yellow oil. R_f=0.4 [V(petroleum ether):V(ethyl acetate)=10:1]; ¹H NMR (DMSO-d₆, 500 MHz) δ: 7.80 (d, J=5.0 Hz, 1H), 7.56 (d, J=7.7 Hz, 2H), 7.45 (d, J=3.4 Hz, 1H), 7.37~7.28 (m, 3H), 7.18~7.14 (m, 1H), 4.40~4.34 (m, 1H), 4.31~4.22 (m, 2H), 3.23 (d, J=6.7 Hz, 2H); ¹³C NMR (DMSO-d₆, 125 MHz) δ: 158.8, 136.9, 132.4, 131.4, 131.3, 129.8, 129.7, 128.5, 127.5, 69.1, 52.4, 33.0; HRMS (ESI-TOF) calcd for C₁₄H₁₄NS₂Se [M+H]⁺ 339.9733, found 339.9734.

  2-Cyclohexyl-5-((phenylselanyl)methyl)-4, 5-dihydro- thiazole (3o): 36 mg, 53% yield, light yellow oil. R_f=0.3 [V(petroleum ether):V(ethyl acetate)=10:1]; ¹H NMR (DMSO-d₆, 500 MHz) δ: 7.54~7.50 (m, 2H), 7.35~7.28 (m, 3H), 4.20~4.14 (m, 1H), 4.06 (dd, J=8.0, 1.4 Hz, 1H), 4.03~3.98 (m, 1H), 3.10 (d, J=6.9 Hz, 2H), 2.49~2.41 (m, 1H), 1.85 (t, J=12.5 Hz, 2H), 1.73~1.68 (m, 2H), 1.62 (d, J=12.2 Hz, 1H), 1.41~1.28 (m, 4H), 1.22~1.15 (m, 1H); ¹³C NMR (DMSO-d₆, 125 MHz) δ: 173.0, 132.4, 129.8, 127.4, 68.9, 50.5, 42.9, 33.4, 31.5, 31.4, 25.9, 25.6; HRMS (ESI-TOF) calcd for C₁₆H₂₂NSSe [M+H]⁺ 340.0638, found 340.0636.

  2-Phenyl-5-((p-tolylselanyl)methyl)-4, 5-dihydrothiazole (3p): 46 mg, 66% yield, light yellow oil. R_f=0.4 [V(petroleum ether):V(ethyl acetate)=10:1]; ¹H NMR (DMSO-d₆, 500 MHz) δ: 7.77 (d, J=7.4 Hz, 2H), 7.55 (t, J=7.2 Hz, 1H), 7.52~7.44 (m, 4H), 7.16 (d, J=7.9 Hz, 2H), 4.45 (dd, J=16.4, 3.7 Hz, 1H), 4.32 (dd, J=16.4, 8.1 Hz, 1H), 4.25~4.11 (m, 1H), 3.17 (d, J=7.4 Hz, 2H), 2.30 (s, 3H); ¹³C NMR (DMSO-d₆, 125 MHz) δ: 165.5, 137.2, 133.2, 133.1, 131.8, 130.5, 129.2, 128.4, 125.7, 69.6, 51.3, 33.5, 21.1; HRMS (ESI-TOF) calcd for C₁₇H₁₈- NSSe [M+H]⁺ 348.0325, found 348.0324.

  5-(((4-Methoxyphenyl)selanyl)methyl)-2-phenyl-4, 5- dihydrothiazole (3q): 44 mg, 61% yield, light yellow oil. R_f=0.3 [V(petroleum ether):V(ethyl acetate)=10:1]; ¹H NMR (DMSO-d₆, 500 MHz) δ: 7.77 (d, J=7.5 Hz, 2H), 7.56~7.47 (m, 5H), 6.92 (d, J=8.5 Hz, 2H), 4.44 (dd, J=16.4, 3.7 Hz, 1H), 4.32 (dd, J=16.4, 8.1 Hz, 1H), 4.18~4.11 (m, 1H), 3.77 (s, 3H), 3.10 (d, J=7.4 Hz, 2H); ¹³C NMR (DMSO-d₆, 125 MHz) δ: 165.5, 159.6, 135.7, 133.3, 131.8, 129.2, 128.4, 119.0, 115.6, 69.6, 55.6, 51.4, 34.3; HRMS (ESI-TOF) calcd for C₁₇H₁₈NOSSe [M+H]⁺ 364.0274, found 364.0279.

  5-(((4-Chlorophenyl)selanyl)methyl)-2-phenyl-4, 5- dihydrothiazole (3r): 24 mg, 33% yield, light yellow oil. R_f=0.3 [V(petroleum ether):V(ethyl acetate)=10:1]; ¹H NMR (DMSO-d₆, 500 MHz) δ: 7.77 (d, J=7.5 Hz, 2H), 7.56 (dd, J=14.2, 7.8 Hz, 3H), 7.50 (t, J=7.5 Hz, 2H), 7.38 (d, J=8.3 Hz, 2H), 4.45 (dd, J=16.3, 3.5 Hz, 1H), 4.34 (dd, J=16.3, 8.0 Hz, 1H), 4.28~4.20 (m, 1H), 3.25 (d, J=7.3 Hz, 2H); ¹³C NMR (DMSO-d₆, 125 MHz) δ: 165.5, 134.1, 133.2, 132.4, 131.9, 129.7, 129.2, 128.6, 128.4, 69.7, 51.2, 33.4; HRMS (ESI-TOF) calcd for C₁₆H₁₅ClNSSe [M+H]⁺ 367.9779, found 367.9779.

  5-((Naphthalen-1-ylselanyl)methyl)-2-phenyl-4, 5- dihydrothiazole (3s): 46 mg, 60% yield, light yellow oil. R_f=0.3 [V(petroleum ether):V(ethyl acetate)=10:1]; ¹H NMR (DMSO-d₆, 500 MHz) δ: 8.28 (d, J=8.3 Hz, 1H), 7.99~7.86 (m, 3H), 7.76 (d, J=7.7 Hz, 2H), 7.65~7.46 (m, 6H), 4.47 (dd, J=16.4, 3.2 Hz, 1H), 4.35~4.27 (m, 1H), 4.22~4.14 (m, 1H), 3.29~3.22 (m, 2H); ¹³C NMR (DMSO-d₆, 125 MHz) δ: 165.5, 134.1, 133.8, 133.2, 132.3, 131.8, 129.2, 128.7, 128.6, 128.4, 127.5, 127.1, 126.9, 126.6, 69.8, 51.3, 33.6; HRMS (ESI-TOF) calcd for C₂₀H₁₈NSSe [M+H]⁺ 384.0325, found 384.0325.

  2-Phenyl-5-((thiophen-2-ylselanyl)methyl)-4, 5-dihydro- thiazole (3t): 32 mg, 47% yield, light yellow oil. R_f=0.3 [V(petroleum ether):V(ethyl acetate)=10:1]; ¹H NMR (DMSO-d₆, 500 MHz) δ: 7.78 (d, J=7.2 Hz, 2H), 7.71 (d, J=5.2 Hz, 1H), 7.52 (dt, J=28.1, 7.2 Hz, 3H), 7.34 (d, J=3.3 Hz, 1H), 7.09 (dd, J=5.1, 3.6 Hz, 1H), 4.47 (dd, J=16.4, 3.5 Hz, 1H), 4.35 (dd, J=16.4, 8.1 Hz, 1H), 4.21~4.13 (m, 1H), 3.13~3.03 (m, 2H); ¹³C NMR (DMSO-d₆, 125 MHz) δ: 165.4, 136.6, 133.2, 132.4, 131.9, 129.2, 129.1, 128.4, 122.5, 69.5, 51.1, 37.2; HRMS (ESI- TOF) calcd for C₁₄H₁₄NS₂Se [M+H]⁺ 339.9733, found 339.9731.

  5-((Methylselanyl)methyl)-2-phenyl-4, 5-dihydrothiazole (3u): 37 mg, 68% yield, light yellow oil. R_f=0.3 [V(petro-leum ether):V(ethyl acetate)=10:1]; ¹H NMR (DMSO- d₆, 500 MHz) δ: 7.82~7.77 (m, 2H), 7.55 (t, J=7.2 Hz, 1H), 7.50 (t, J=7.3 Hz, 2H), 4.46~4.40 (m, 1H), 4.38~4.30 (m, 2H), 2.83~2.75 (m, 2H), 2.06 (s, 3H); ¹³C NMR (DMSO-d₆, 125 MHz) δ: 165.6, 133.4, 131.8, 129.2, 128.3, 69.8, 51.5, 31.0, 4.6; HRMS (ESI-TOF) calcd for C₁₁H₁₄N- SSe [M+H]⁺ 272.0012, found 272.0014.

  5-((Cyclohexylselanyl)methyl)-2-phenyl-4, 5-dihydro- thiazole (3v): 40 mg, 59% yield, light yellow oil. R_f=0.4 [V(petroleum ether):V(ethyl acetate)=10:1]; ¹H NMR (DMSO-d₆, 500 MHz) δ: 7.78 (d, J=7.3 Hz, 2H), 7.55 (t, J=7.2 Hz, 1H), 7.50 (t, J=7.4 Hz, 2H), 4.42 (dd, J=16.0, 3.7 Hz, 1H), 4.34 (dd, J=16.0, 7.8 Hz, 1H), 4.32~4.24 (m, 1H), 3.13~3.04 (m, 1H), 2.89~2.78 (m, 2H), 1.99 (d, J=12.9 Hz, 2H), 1.72~1.64 (m, 2H), 1.57 (dd, J=10.3, 4.2 Hz, 1H), 1.49~1.41 (m, 2H), 1.37~1.27 (m, 3H); ¹³C NMR (DMSO-d₆, 125 MHz) δ: 165.5, 133.3, 131.7, 129.2, 128.3, 69.9, 52.3, 39.1, 34.7, 28.3, 26.6, 25.7; HRMS (ESI- TOF) calcd for C₁₆H₂₂NSSe [M+H]⁺ 340.0638, found 340.0635.

  5-((Benzylselanyl)methyl)-2-phenyl-4, 5-dihydrothiazole (3w): 36 mg, 52% yield, light yellow oil. R_f=0.3 [V(petroleum ether):V(ethyl acetate)=10:1]; ¹H NMR (DMSO-d₆, 500 MHz) δ: 7.78 (d, J=8.0 Hz, 2H), 7.55 (t, J=7.2 Hz, 1H), 7.49 (t, J=7.4 Hz, 2H), 7.32 (q, J=8.25, 7.8 Hz, 4H), 7.23 (t, J=6.9 Hz, 1H), 4.38 (dd, J=15.6, 2.8 Hz, 1H), 4.30 (dd, J=15.9, 7.8 Hz, 1H), 4.25 (dt, J=7.3, 3.6 Hz, 1H), 3.94 (s, 2H), 2.75 (d, J=7.0 Hz, 2H); ¹³C NMR (DMSO-d₆, 125 MHz) δ: 165.5, 139.9, 133.3, 131.8, 129.3, 129.2, 128.9, 128.3, 127.1, 69.9, 51.5, 29.7, 27.1; HRMS (ESI-TOF) calcd for C₁₇H₁₈NSSe [M+H]⁺ 348.0325, found 348.0327.

  5-(Cyclopropyl(phenylselanyl)methyl)-2-phenyl-4, 5- dihydrothiazole (3x): 40 mg, 54% yield, light yellow oil. R_f=0.3 [V(petroleum ether):V(ethyl acetate)=10:1]; ¹H NMR (DMSO-d₆, 500 MHz) δ: 7.77 (d, J=7.6 Hz, 2H), 7.69~7.63 (m, 2H), 7.50 (t, J=7.3 Hz, 1H), 7.44 (t, J=7.4 Hz, 2H), 7.41~7.33 (m, 3H), 4.23 (dd, J=17.0, 3.4 Hz, 1H), 3.94 (dd, J=17.0, 7.9 Hz, 1H), 3.81~3.73 (m, 1H), 3.05 (t, J=8.8 Hz, 1H), 1.18~1.09 (m, 1H), 0.70~0.63 (m, 1H), 0.63~0.56 (m, 1H), 0.48~0.42 (m, 1H), 0.38~0.30 (m, 1H); ¹³C NMR (DMSO-d₆, 125 MHz) δ: 157.8, 138.6, 134.5, 131.1, 129.8, 128.9, 128.2, 126.3, 53.7, 51.1, 41.4, 17.9, 7.1, 4.1; HRMS (ESI-TOF) calcd for C₁₉H₂₀NSSe [M+H]⁺ 374.0482, found 374.0480.

  5-((Phenylselanyl)methyl)-2-(trifluoromethyl)-4, 5- dihydrothiazole (4a): 56 mg, 86% yield, light yellow oil. R_f=0.5 [V(petroleum ether):V(ethyl acetate)=10:1]; ¹H NMR (DMSO-d₆, 500 MHz) δ: 7.59~7.52 (m, 2H), 7.37~7.29 (m, 3H), 4.52~4.43 (m, 2H), 4.42~4.34 (m, 1H), 3.30~3.22 (m, 2H); ¹³C NMR (DMSO-d₆, 125 MHz): δ 157.4 (q, J=37.5 Hz), 132.5, 129.9, 129.2, 127.6, 118.9 (q, J=275.5 Hz), 68.9, 53.8, 32.3; ¹⁹F NMR (DMSO-d₆, 375 MHz) δ: -65.82; HRMS (ESI-TOF) calcd for C₁₁H₁₁F₃NSSe [M+H]⁺ 325.9730, found 325.9728.

  5-((Naphthalen-1-ylselanyl)methyl)-2-(trifluoromethyl)-4, 5-dihydrothiazole (4b): 59 mg, 79% yield, light yellow oil. R_f=0.4 [V(petroleum ether):V(ethyl acetate)=10:1]; ¹H NMR (DMSO- d₆, 500 MHz) δ: 8.26 (d, J=8.3 Hz, 1H), 7.96 (dd, J=18.4, 8.1 Hz, 2H), 7.88 (d, J=7.1 Hz, 1H), 7.62 (dt, J=25.9, 7.2 Hz, 2H), 7.48 (t, J=7.7 Hz, 1H), 4.48 (d, J=15.5 Hz, 1H), 4.43~4.33 (m, 2H), 3.33~3.25 (m, 2H); ¹³C NMR (DMSO-d₆, 125 MHz) δ: 156.4 (q, J=37.4 Hz), 133.1, 132.8, 131.5, 128.2, 127.9, 127.0, 126.5, 126.1, 125.9, 125.6, 117.9 (q, J=275.6 Hz), 68.0, 52.8, 31.6; ¹⁹F NMR (DMSO-d₆, 375 MHz) δ: -65.78; HRMS (ESI-TOF) calcd for C₁₅H₁₃F₃NSSe [M+H]⁺ 375.9886, found 375.9890.

  5-((Methylselanyl)methyl)-2-(trifluoromethyl)-4, 5- dihydrothiazole (4c): 46 mg, 88% yield, light yellow oil. R_f=0.4 [V(petroleum ether):V(ethyl acetate)=10:1]; ¹H NMR (DMSO-d₆, 500 MHz) δ: 4.60~4.50 (m, 1H), 4.45~4.30 (m, 2H), 2.78 (d, J=7.4 Hz, 2H), 2.01 (s, 3H); ¹³C NMR (DMSO-d₆, 125 MHz) δ: 157.5 (q, J=37.8 Hz), 118.9 (q, J=275.7 Hz), 69.0, 53.9, 30.1, 4.6; ¹⁹F NMR (DMSO-d₆, 375 MHz) δ: -65.87; HRMS (ESI-TOF) calcd for C₆H₉F₃NSSe [M+H]⁺ 263.9573, found 263.9575.

  5-Methyl-5-((phenylselanyl)methyl)-2-(trifluoro- methyl)-4, 5-dihydrothiazole (4d): 56 mg, 83% yield, light yellow oil. R_f=0.5 [V(petroleum ether):V(ethyl aceta-te)=10:1]; ¹H NMR (DMSO-d₆, 500 MHz) δ: 7.61~7.54 (m, 2H), 7.37~7.27 (m, 3H), 4.35 (dd, J=16.9, 2.3 Hz, 1H), 4.22 (dd, J=16.9, 2.3 Hz, 1H), 3.59~3.45 (m, 2H), 1.60 (s, 3H); ¹³C NMR (DMSO-d₆, 125 MHz) δ: 157.5 (q, J=37.8 Hz), 132.4, 130.6, 129.8, 127.6, 118.7 (q, J=275.9 Hz), 74.2, 68.5, 38.7, 27.1; ¹⁹F NMR (DMSO-d₆, 375 MHz) δ: -66.31; HRMS (ESI-TOF) calcd for C₁₂H₁₃F₃NSSe [M+H]⁺ 339.9886, found 339.9885.

  5-Phenyl-5-((phenylselanyl)methyl)-2-(trifluoromethyl)-4, 5-dihydrothiazole (4e): 30 mg, 37% yield, light yellow oil. R_f=0.4 [V(petroleum ether):V(ethyl acetate)=10:1]; ¹H NMR (DMSO-d₆, 500 MHz) δ: 7.45 (d, J=7.5 Hz, 2H), 7.41~7.35 (m, 4H), 7.33 (t, J=7.2 Hz, 1H), 7.25 (dd, J=4.7, 1.6 Hz, 3H), 4.91~4.85 (m, 1H), 4.65 (dd, J=17.0, 2.4 Hz, 1H), 3.84 (s, 2H); ¹³C NMR (DMSO-d₆, 125 MHz) δ: 157.6 (q, J=37.8 Hz), 141.0, 132.5, 130.5, 129.6, 129.1, 128.5, 127.6, 127.1, 118.7 (q, J=275.6 Hz), 74.3, 73.6, 29.5; ¹⁹F NMR (DMSO-d₆, 375 MHz) δ: -66.15; HRMS (ESI-TOF) calcd for C₁₇H₁₅F₃NSSe [M+H]⁺ 402.0043, found 402.0044.

  5-(2-(Phenylselanyl)propan-2-yl)-2-(trifluoromethyl)- 4, 5-dihydrothiazole (4f): 37 mg, 53% yield, light yellow oil. R_f=0.6 [V(petroleum ether):V(ethyl acetate)=20:1]; ¹H NMR (DMSO-d₆, 500 MHz) δ: 7.65 (d, J=7.4 Hz, 2H), 7.50 (t, J=7.3 Hz, 1H), 7.43 (t, J=7.4 Hz, 2H), 4.68~4.60 (m, 1H), 4.52~4.42 (m, 2H), 1.31 (d, J=12.5 Hz, 6H); ¹³C NMR (DMSO-d₆, 125 MHz) δ: 156.6 (q, J=37.1 Hz), 138.0, 129.4, 129.3, 125.6, 118.3 (q, J=275.2 Hz), 65.7, 64.0, 48.9, 26.1, 24.5; ¹⁹F NMR (DMSO-d₆, 375 MHz) δ: -65.89; HRMS (ESI-TOF) calcd for C₁₃H₁₅F₃- NSSe [M+H]⁺ 354.0043, found 345.0046.

  Supporting Information  Reaction equipment, cyclic voltammetry experiment and NMR spectra of new compounds. The Supporting Information is available free of charge via the Internet at http://sioc-journal.cn/.

  
  
• 1. [1]

     (a) Yuichi, O.; Yuichi, M.; Masahito, Y.; Takayuki, D. J. Med. Chem. 2017, 60, 6751.
     (b) Conley, N. R.; Andrasi, A.-D.; Rao, J.; Moerner, W. E. Angew. Chem.. Int. Ed. 2012, 51, 3350.
     (c) Marson, C. M.; Matthews, C. J.; Yiannaki, E.; Atkinson, S. J.; Soden, P. E.; Shukla, L.; Lamadema, N.; Thomas, N. S. B. J. Med. Chem. 2013, 56, 6156.
     (d) Altıntop, M. D.; Kaplancıklı, Z. A.; Çiftçi, G. A.; Demirel, R. Eur. J. Med. Chem. 2014, 74, 264.

  2. [2]

     (a) Du, D.-M.; Lu, S.-F.; Fang, T.; Xu, J. J. Org. Chem. 2005, 70, 3712.
     (b) Mellah, M.; Voituriez, A.; Schulz, E. Chem. Rev. 2007, 107, 5133.
     (c) Liu, L.; Li, J.; Wang, M.; Du, F.; Qin, Z.; Fu, B. Tetrahedron. Asymmetry 2011, 22, 550.

  3. [3]

     (a) Alom, N. E.; Wu, F.; Li, W. Org. Lett. 2017, 19, 930.
     (b) Gaumont, A. C.; Gulea, M.; Levillain, J. Chem. Rev. 2009, 109, 1371.
     (c) Jeon, H.; Kim D.; Lee, J. H.; Song J.; Lee, W. S.; Kang, D. W.; Kang, S.; Lee, S. B.; Choi, S.; Hong, K. B. Adv. Synth. Catal. 2018, 360, 779.

  4. [4]

     (a) Trose, M.; Lazreg, F.; Lesieur, M.; Cazin, C. S. J. Green Chem. 2015, 17, 3090.
     (b) Maltsev, O. V.; Walter, V.; Brandl, M. J.; Hintermann, L. Synthesis 2013, 45, 2763.

  5. [5]

     (a) Qumruddeen; Yadav, A.; Kant, R.; Tripathi, C. B. J. Org. Chem. 2020, 85, 2814.
     (b) Morse, P. D.; Nicewicz, D. A. Chem. Sci. 2015, 6, 270.
     (c) Liu, G.-Q.; Yang, C.-H.; Li, Y.-M. J. Org. Chem. 2015, 80, 11339.

  6. [6]

     Shao, L.; Li, Y.; Lu, J.; Jiang, X. Org. Chem. Front. 2019, 6, 2999. doi: 10.1039/C9QO00620F

  7. [7]

     (a) Seng, H.-L.; Tiekink, E. R. T. Appl. Organomet. Chem. 2012, 26, 655.
     (b) Sahu, .P. K.; Umme, T.; Yu, J.; Nayak, A.; Kim, G.; Noh, M.; Lee, J.-Y.; Kim, D.-D.; Jeong, L. S. J. Med. Chem. 2015, 58, 8734.
     (c) Nogueira, C. W.; Zeni, G.; Rocha. J. B. T. Chem. Rev. 2004, 104, 6255.

  8. [8]

     (a) Engman, L. J. Org. Chem. 1991, 56, 3425.
     (b) Sahoo, H.; Singh, S.; Baidya, M. Org. Lett. 2018, 20, 3678.
     (c) Wang, X.; Mu, S.; Sun, T.; Sun, K. Chin. J. Org. Chem. 2019, 39, 2802(in Chinese).
     (王薪, 穆石强, 孙婷, 孙凯, 有机化学, 2019, 39, 2802.)
     (d) Wang, M.; Wu, Z.; Zhu, C. Org. Chem. Front. 2017, 4, 427.
     (e) Reddy, C. R.; Ranjan, R.; Prajapti, S. K. Org. Lett. 2019, 21, 623.

  9. [9]

     Zhang, Q.-B.; Yuan, P.-F.; Kai, L.-L.; Liu, K.; Ban, Y.-L.; Wang, X.-Y.; Wu, L.-Z.; Liu, Q. Org. Lett. 2019, 21, 885. doi: 10.1021/acs.orglett.8b03738

  10. [10]

      Yu, J.-M.; Cai, C. Org. Biomol. Chem. 2018, 16, 490. doi: 10.1039/C7OB02892J

  11. [11]

      Casola, K. K.; Back, D. F.; Zeni, G. J. Org. Chem. 2015, 80, 7702. doi: 10.1021/acs.joc.5b01448

  12. [12]

      Sun, K.; Wang, S.; Feng, R.; Zhang, Y.; Wang, X.; Zhang, Z.; Zhang, B. Org. Lett. 2019, 21, 2052. doi: 10.1021/acs.orglett.9b00240

  13. [13]

      (a) Xiong, P.; Xu, H.-C. Acc. Chem. Res. 2019, 52, 3339.
      (b) Yuan, Y.; Lei, A. Acc. Chem. Res. 2019, 52, 3309.
      (c) Jiang, Y.; Xu, K.; Zeng, C. Chem. Rev. 2018, 118, 4485.
      (d) Yan, M.; Kawamata, Y.; Baran, P. S. Chem. Rev. 2017, 117, 13230.

  14. [14]

      (a) Adeli, Y.; Huang, K.-M.; Liang, Y.-J.; Jiang, Y.-Y.; Liu, J.-Z.; Song, S.; Zeng, C.-C.; Jiao, N. ACS Catal. 2019, 9, 2063.
      (b) Huang, M.; Dai, J.; Cheng, X.; Ding, M. Org. Lett. 2019, 21, 7759.
      (c) Lian, F.; Sun, C.; Xu, K.; Zeng, C. Org. Lett. 2019, 21, 156.
      (d) Zhang, S.; Li, L.; Xue, M.; Zhang, R.; Xu, K.; Zeng, C. Org. Lett. 2018, 20, 3443.
      (e) Huang, C.; Qian, X.-Y.; Xu, H.-C. Angew. Chem.. Int. Ed. 2019, 58, 6650.
      (f) Feng, E.-Q.; Hou, Z.-W.; Xu, H.-C. Chin. J. Org. Chem. 2019, 39, 1424(in Chinese).
      (冯恩祺, 侯中伟, 徐海超, 有机化学, 2019, 39, 1424.)
      (g) Hou, Z.-W.; Xu, H.-C. Chin. J. Chem. 2020, 38, 394.
      (h) Liu, W.-Q.; Yang, X.-L.; Tung, C.-H.; Wu, L.-Z. Acta Chim. Sinica 2019, 77, 861(in Chinese).
      (刘文强, 杨修龙, 佟振合, 吴骊珠, 化学学报, 2019, 77, 861.)

  15. [15]

      (a) Li, Q.-Y.; Cheng, S.-Y.; Tang, H.-T.; Pan, Y.-M. Green Chem. 2019, 21, 5517.
      (b) Cao, Y.; Yuan, Y.; Lin, Y.; Jiang, X.; Weng, Y.; Wang, T.; Bu, F.; Zeng, L.; Lei, A. Green Chem. 2020, 22, 1548.
      (c) Meng, X.-J.; Zhong, P.-F.; Wang, Y.-M.; Wang, H.-S.; Tang, H.-T.; Pan, Y.-M. Adv. Synth. Catal. 2020, 362, 506.
      (d) He, M.-X.; Mo, Z.-Y.; Wang, Z.-Q.; Cheng, S.-Y.; Xie, R.-R.; Tang, H.-T.; Pan, Y.-M. Org. Lett. 2020, 22, 724.
      (e) Wang, Z.-Q.; Meng, X.-J.; Li, Q.-Y.; Tang, H.-T.; Wang, H.-S.; Pan, Y.-M. Adv. Synth. Catal. 2018, 360, 4043.
      (f) Zhang, Z.; Zhang, L.; Cao, Y.; Li, F.; Bai, G.; Liu, G.; Yang, Y.; Mo, F. Org. Lett. 2019, 21, 762.
      (g) Wang, Z.-Q.; Hou, C.; Zhong, Y.-F.; Lu, Y.-X.; Mo, Z.-Y.; Pan, Y.-M.; Tang, H.-T. Org. Lett. 2019, 21, 9841.
      (h) Li, D.; Seavill, P. W.; Wilden, D. J. D. ChemElectroChem 2019, 6, 5829.

  16. [16]

      Sun, L.; Yuan, Y.; Yao, M.; Wang, H.; Wang, D.; Gao, M.; Chen, Y.-H.; Lei, A. Org. Lett. 2019, 21, 1297. doi: 10.1021/acs.orglett.8b03274

  17. [17]

      Guan, Z.; Wang, Y.; Wang, H.; Huang, Y.; Wang, S.; Tang, H.; Zhang, H.; Lei, A. Green Chem. 2019, 21, 4976. doi: 10.1039/C9GC02665G

  18. [18]

      Mallick, S.; Baidya, M.; Mahanty, K.; Maiti, D.; Sarkar, S. D. Adv. Synth. Catal. 2020, 362, 1046. doi: 10.1002/adsc.201901262

  19. [19]

      (a) Guo, W.-S.; Wen, L.-R.; Li, M. Org. Biomol. Chem. 2015, 13, 1942.
      (b) Guo, W.-S.; Gong, H.; Zhang, Y.-A.; Wen, L.-R.; Li, M. Org. Lett. 2018, 20, 6394.
      (c) Li, M.; Cao, H.; Wang, Y.; Lv, X.-L.; Wen, L.-R. Org. Lett. 2012, 14, 3470.

  20. [20]

      (a) Meanwell, N. A. J. Med. Chem. 2018, 61, 5822.
      (b) Charpentier, J.; Früh, N.; Togni, A. Chem. Rev. 2015, 115, 650.
      (c) Qing, F. Chin. J. Org. Chem. 2012, 32, 815(in Chinese).
      (卿凤翎, 有机化学, 2012, 32, 815.)

  21. [21]

      (d) Zhang, F.; Peng, X.; Ma, J. Chin. J. Org. Chem. 2019, 39, 109(in Chinese).
      (张发光, 彭星, 马军安, 有机化学, 2019, 39, 109.)

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  Scheme 1  Electrochemical reactions based on diselenides

  下载: 全尺寸图片 幻灯片
  

  Scheme 2  Gram-scale and control experiments

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  Scheme 3  Possible mechanism

  下载: 全尺寸图片 幻灯片

  Table 1.  Optimization of reaction conditions^a

  Entry	Anode/Cathode	Electrolyte	Solvent	Yieldb/%
  1	CF/CF	LiClO4	CH3CN	68
  2	Pt/C	LiClO4	CH3CN	49
  3	C/Pt	LiClO4	CH3CN	46
  4	C/C	LiClO4	CH3CN	53
  5	CF/CF	nBu4NBF4	CH3CN	15
  6	CF/CF	nBu4NI	CH3CN	0
  7	CF/CF	nBu4NPF6	CH3CN	23
  8	CF/CF	NH4ClO4	CH3CN	51
  9	CF/CF	LiClO4	CH3OH	60
  10	CF/CF	LiClO4	CH3CN/C2H5OH (V:V=1:1)	58
  11	CF/CF	LiClO4	DMF	0
  12	CF/CF	LiClO4	CH3CN/HFIP (V:V=1:1)	16
  13c	CF/CF	LiClO4	CH3CN	66
  14d	CF/CF	LiClO4	CH3CN	40
  15e	CF/CF	LiClO4	CH3CN	65
  16f	CF/CF	LiClO4	CH3CN	56
  17g	CF/CF	LiClO4	CH3CN	54
  18h	CF/CF	LiClO4	CH3CN	0
  a Reaction conditions: CF anode, CF cathode, 1a (0.2 mmol), 2a (0.6 equiv.), electrolyte (1.5 equiv), solvent (4 mL), 2 mA, under air, 4 h. b Isolated yields. c T=0 ℃. d T=50 ℃. e Under N2. f 1 mA, 10 h, g 3 mA. h No electric current.

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  Table 2.  Scope of thioamides^{a, b}

  a Reaction conditions: CF anode, CF cathode, 1 (0.2 mmol), 2a (0.6 equiv.), LiClO4 (1.5 equiv.), CH3CN (4 mL), 2 mA, 4 h. b Isolated yields.

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  Table 3.  Scope of the diselenides^{a, b}

  a Reaction conditions: CF anode, CF cathode, 1a (0.2 mmol), 2 (0.6 equiv.), LiClO4 (1.5 equiv.), CH3CN (4 mL), 2 mA, 4 h. b Isolated yields.

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  Table 4.  Scope of the trifluoromethyl thioamides^{a, b}

  a Reaction conditions: CF anode, CF cathode, 1 (0.2 mmol), 2 (0.6 equiv.), LiClO4 (1.5 equiv.), CH3CN (4 mL), 2 mA, 4 h. b Isolated yields. c Under N2, 8 h.

  下载: 导出CSV
•