Aqueous Reaction of Alcohols, Organohalides, and Odorless Sodium

Sep 14, 2017 - halides, and odorless sodium thiosulfate in water has been developed. In addition, the aryl sulfides could also be prepared by the reac...
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Aqueous Reaction of Alcohols, Organohalides, and Odorless Sodium Thiosulfate under Transition-Metal-Free Conditions: Synthesis of Unsymmetrical Aryl Sulfides via Dual C−S Bond Formation Bei-Bei Liu,† Xue-Qiang Chu,† Huan Liu,† Ling Yin,‡ Shun-Yi Wang,*,† and Shun-Jun Ji*,† †

Key Laboratory of Organic Synthesis of Jiangsu Province, College of Chemistry, Chemical Engineering and Materials Science and Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University, Suzhou 215123, P. R. China ‡ Department of Chemistry and Chemical Engineering, Jining University, Qufu 273155, P. R. China S Supporting Information *

ABSTRACT: A transition-metal-free process for the synthesis of unsymmetrical aryl sulfides via dual C−S bond formation by a one-pot three-component reaction of alcohols, organohalides, and odorless sodium thiosulfate in water has been developed. In addition, the aryl sulfides could also be prepared by the reaction of the corresponding alcohols and Bunte salts under the identical conditions. This protocol provides a green and efficient manner for the construction of various unsymmetrical aryl sulfides.

1. INTRODUCTION Sulfur-containing compounds are great core scaffolds among various nature products, drugs, and materials.1,2 They show high pharmacological and biological activities for their unique molecular structures (Figure 1).3,4 Moreover, they are also widely used as functional materials,5,6 metal ligands,7 and organic synthesis intermediates.8

applications, further development of a cheaper, low-toxic, ecofriendly benign and metal-free methodology incorporating the sulf-functionality is still urgently desired. Recently, our group has reported the sulfuration reaction and sulfur insertion reactions under transition-metal-free conditions.15,16 As a continued interest in C−S bond formation reactions, herein, we demonstrate a novel method for the synthesis of unsymmetrical aryl sulfides by a one-pot three-component reaction of alcohols, organohalides, and odorless sodium thiosulfate under mild conditions. The in situ generated nucleophilic Bunte salts from sodium thiosulfate with halides react with alcohols to afford unsymmetrical aryl sulfides via dual C−S bond formation under aqueous conditions.

2. RESULTS AND DISCUSSION In a preliminary reaction, the halide 1a reacted with anisyl alcohol 2a and sodium thiosulfate in the presence of HCl in water at 100 °C for 12 h. To our delight, the desired product 4(((4-methoxybenzyl)thio)methyl)benzonitrile 3a was obtained in 18% GC-yield (Table 1, entry 1). Increasing the amount of HCl (Table 1, entries 2−5) indicated that 1.0 equiv of HCl could improve the yield of 3a to 85% (81% isolated yield). Further changing the ratio of 1a lead to lower yields (Table 1, entries 6−7). However, when the reaction was carried out in toluene, DCE, DMSO, 1,4-dioxane, respectively, the product was not observed at all under these reaction conditions (Table 1, entries 8−11). Further examination of the sulfur source, such as K2S and S8, was investigated (Table 1, entries 12−13), and poor results were obtained.

Figure 1. Sulfur compounds and pharmaceutical relevant thioethers.

A series of strategies to form carbon−sulfur (C−S) bonds have been investigated, which are summarized as follows: (1) The transition-metal-catalyzed homocoupling reaction of halides with disulfides9 or thiols,10 sulfonyl halides,11 and their related derivatives;12 (2) multicomponents and tandem reactions to assemble different substituted sulfether;13 and (3) multiple unsaturated electrophilic reagents undergo nucleophilic addition reactions.14 Nevertheless, thiols and disulfides are fetid, toxic, and sensitive. In addition, over-oxidation is unavoidable with the utilization of expensive transition-metal catalysts. Based on the aforesaid restriction of practical © 2017 American Chemical Society

Received: July 3, 2017 Published: September 14, 2017 10174

DOI: 10.1021/acs.joc.7b01653 J. Org. Chem. 2017, 82, 10174−10180

Article

The Journal of Organic Chemistry Table 1. Optimization of the Reaction Conditionsa

a b

entry

1a (mmol)

1 2 3 4 5 6 7 8 9 10 11 12d 13e

2.0 2.0 2.0 2.0 2.0 1.5 1.2 2.0 2.0 2.0 2.0 2.0 2.0

additive (equiv) HCl HCl HCl HCl HCl HCl HCl HCl HCl HCl HCl HCl HCl

(0.25) (0.5) (1.0) (1.5) (2.0) (1.0) (1.0) (1.0) (1.0) (1.0) (1.0) (1.0) (1.0)

solvent

yieldb (%)

H2O H2O H2O H2O H2O H2O H2O toluene DCE DMSO 1,4-dioxane H2O H2O

18 32 85 (81c) 45 50 59 53 0 trace trace 0 22 0

Reagents and conditions: 1a (x mmol), S-source (1.5 mmol), 2a (0.5 mmol), HCl (0.5 mmol, 36−38% in aqueous solution) in solvent (2 mL). Yields were determined by GC with an internal standard (biphenyl). cYields of isolated products. dK2S as S-source. eS8 as S-source.

Table 2. Substrate Scope of Benzyl Alcohols and Halidesa

Reagents and conditions: 1 (0.5 mmol, X = Cl unless otherwise instructed), Na2S2O3·5H2O (1.5 mmol), 2 (1.0 mmol), HCl (0.5 mmol, 36−38% in aqueous solution), in water (2 mL), 100 °C for 12 h. bX = Br. c1 (0.5 mmol) and Bunte salt (1.0 mmol) in water (2 mL).

a

In view of the high reactivity of Bunte salts, various Bunte salts 4 bearing different functional groups were prepared in high yields from the corresponding halides with sodium thiosulfate (Table 3). Then, we studied the reactions of piperonol with various Bunte salts 4 under the similar reaction conditions. It should be noted that most of the reactions underwent smoothly to afford the desired products in improved yields comparing with three-component reactions. Sodium S-benzyl sulfurothioates bearing electron-withdrawing and neutral functional groups were good substrates for the reaction to deliver the desired sulfides 5c−g in good to excellent yields. Notably, the ethyl butyrate derivative 5h was obtained in 49% yield. Unfortunately, the reaction of piperonol with sodium S-((9Hfluoren-9-yl)methyl) only led to trace amount of the desired product 5i. These results indicated that Bunte salt is the key intermediate for the three-component reaction of alcohols, halides, and odorless sodium thiosulfate.

With the optimal reaction conditions in hand, we investigated the substrate scope of alkyl halides and alcohols. The reactions of various substituted halides and alcohols afforded the corresponding unsymmetrical aryl sulfides in moderate to good yields. The results are listed in Table 2. The reactions of benzyl halides bearing electron-withdrawing groups (−CN, −NO2) with anisyl alcohol 2a proceeded smoothly to furnish 3a−d in good yields. The reactions of alkyl halides 5bromopentanenitrile and 2-bromo-N,N-diethylpropanamide with 2a also resulted in the desired products 3e and 3f in 78% and 37% yield, respectively. o-OMe benzyl alcohol reacted with 1a to afford the desired product 3g in 54% yield. Piperonyl alcohol was also tolerant to the reaction, giving the expected compounds 3h and 3i in 62% and 42% yields, respectively. It is worth noting that the yield of 3i could be increased to 99% when Bunte salt sodium S-(4-methylbenzyl)sulfurothioate was used as S-source instead of sodium thiosulfate with 1(chloromethyl)-4-methylbenzene. 10175

DOI: 10.1021/acs.joc.7b01653 J. Org. Chem. 2017, 82, 10174−10180

Article

The Journal of Organic Chemistry Table 3. Substrate Scope of Benzyl Alcohols with Alkylsulfidesa

Reagents and conditions: 2 (0.5 mmol), Bunte salt (1.0 mmol), HCl (0.5 mmol, 36−38% in aqueous solution), in water (2 mL) at 100 °C for 12 h. Reagents and conditions: 1 (1.0 mmol), Na2S2O3·5H2O (1.5 mmol), 2 (0.5 mmol), HCl (0.5 mmol, 36−38% in aqueous solution) in water (2 mL) for 12 h. a b

Table 4. Substrate Scope of Propynols and Allylic Alcoholsa

a b

Reagents and conditions: 6 (0.3 mmol), Bunte salt (0.6 mmol), HCl (0.5 mmol, 36−38% in aqueous solution), in water (2 mL) at 100 °C for 12 h. The reaction time is 23 h. cThe reaction time is 13 h. dThe reaction time is 13.5 h. eThe reaction time is 23 h.

yield, which is an analog of Modafinil. Unfortunately, the reaction of sodium S-(2-amino-2-oxoethyl) sulfurothioate with diphenyl methanol failed to result in the desired product. It is worth noting that the reaction of bulky triphenylmethanol with S-(4-cyanobenzyl) sulfurothioate underwent smoothly to afford the corresponding product 9e in 97% yield. Based on the above results and the literatures,17 a plausible mechanism is proposed in Scheme 1. Initially, halide 1 reacts with sodium thiosulfate to generate Bunte salt 4. 4 is activated by H2O to form aryl thiolate anion (or thiol) 4′. Alcohol undergoes dehydration in the presence of HCl to generate the

Encouraged by the above results, we then turned our attention to the reaction of Bunte salt sodium S-(4cyanobenzyl) sulfurothioate 4a with propynols and allylic alcohols (Table 4). It was found that propynols and allylic alcohols were successfully applied to the reaction with 4a to provide various sulfides 7a−f in moderate to good yields. Finally, diaryl methanol and triphenyl methanol have been subjected to the thioetherification reaction under aqueous conditions. As shown in Table 5, sodium S-(4-cyanobenzyl) sulfurothioate reacted with diphenyl methanol to give 9a in 44% yield. Interestingly, the reaction of amide Bunt salt with diphenyl methanol directly led to the desired sulfide 9b in 44% 10176

DOI: 10.1021/acs.joc.7b01653 J. Org. Chem. 2017, 82, 10174−10180

Article

The Journal of Organic Chemistry

mmol), sodium thiosulfate (1.5 mmol), and hydrochloric acid (0.5 mmol) were stirred at 100 °C (oil bath temperature) under air atmosphere in 2 mL of H2O. Upon completion of the reaction (indicated by TLC), the mixture was cooled to room temperature. The reaction was extracted with ethyl acetate (10 mL × 3). The combined organic extracts were dried with sodium sulfate and concentrated. The pure products were obtained after purification by column chromatography on silica gel with petroleum ether/ethyl acetate (v:v = 100:1− 20:1) as the eluent. General Procedure for the Synthesis of Compounds 5 and 9. Alcohol 2 or 8 (0.5 mmol) and Bunte salt 4 (1.0 mmol) were stirred at 100 °C (oil bath temperature) under air atmosphere in 2 mL of water. Upon completion of the reaction (indicated by TLC), the mixture was cooled to room temperature. The reaction was extracted with ethyl acetate (10 mL × 3). The combined organic extracts were dried with sodium sulfate and concentrated. The pure products were obtained after purification by column chromatography on silica gel with petroleum ether/ethyl acetate (v:v = 100:1−20:1) as the eluent. General Procedure for the Synthesis of Compounds 7. Propynols or allylic alcohols 6 (0.3 mmol) and Bunte salt 4a (0.6 mmol) were stirred at 100 °C (oil bath temperature) under air atmosphere in 2 mL of water. Upon completion of the reaction (indicated by TLC), the mixture was cooled to room temperature. The reaction was extracted with ethyl acetate (10 mL × 3). The combined organic extracts were dried with sodium sulfate and concentrated. The pure products were obtained after purification by column chromatography on silica gel with petroleum ether/ethyl acetate (v:v = 100:1− 20:1) as the eluent. 4-(((4-Methoxybenzyl)thio)methyl)benzonitrile (3a). White solid (109 mg, 81%). Mp 53.5−54.3 °C. IR 2931, 2835, 2218, 1605, 1508, 1418, 1302, 1245, 1036, 835 cm−1. 1H NMR (400 MHz, Chloroformd) δ 7.59 (d, J = 8.1 Hz, 2H), 7.36 (d, J = 8.0 Hz, 2H), 7.17 (d, J = 2.0 Hz, 2H), 6.89−6.80 (m, 2H), 3.80 (s, 3H), 3.59 (s, 2H), 3.55 (s, 2H). 13 C NMR (100 MHz, CDCl3) δ 158.9, 144.2, 132.3, 130.1, 129.8, 129.4, 118.9, 114.1, 110.8, 55.4, 35.3 ppm. HRMS (ESI) m/z: calcd for C16H15NONaS [M + Na]+ 292.0767, found: 292.0771. (4-Methoxybenzyl)(4-nitrobenzyl)sulfane (3b). Yellow solid (86 mg, 62%). Mp 47.8−50.4 °C. IR 2893, 2837, 1605, 1510, 1338, 1241, 1170, 1105, 856, 709 cm−1. 1H NMR (400 MHz, Chloroform-d) δ 8.21 (d, J = 8.7 Hz, 2H), 7.47 (d, J = 8.7 Hz, 2H), 7.22 (d, J = 8.6 Hz, 2H), 6.90 (d, J = 8.6 Hz, 2H), 3.86 (s, 3H), 3.69 (s, 2H), 3.62 (s, 2H). 13 C NMR (100 MHz, CDCl3) δ 158.9, 147.1, 146.3, 130.2, 129.9, 129.3, 123.8, 114.1, 55.4, 35.4, 35.0 ppm. HRMS (ESI) m/z: calcd for C15H15NO3SNa [M + Na]+ 312.0665, found: 312.0675. 3-(((4-Methoxybenzyl)thio)methyl)benzonitrile (3c). Yellow oil (113 mg, 84%). IR 2835, 1608, 1509, 1300, 1246, 1174, 1032, 833, 685 cm−1. 1H NMR (400 MHz, Chloroform-d) δ 7.58−7.46 (m, 3H), 7.40 (t, J = 7.9 Hz, 1H), 7.17 (d, J = 8.7 Hz, 2H), 6.89−6.81 (m, 2H), 3.81 (s, 3H), 3.58 (s, 2H), 3.57 (s, 2H). 13C NMR (100 MHz, CDCl3) δ 158.9, 140.2, 133.6, 132.6, 130.8, 130.2, 129.4, 129.4, 114.1, 112.6, 100.1, 55.4, 35.4, 34.9 ppm. HRMS (ESI) m/z: calcd for C16H15NONaS [M + Na]+ 292.0767, found: 292.0762. 2-(((4-Methoxybenzyl)thio)methyl)benzonitrile (3d). Yellow oil (71 mg, 53%). IR 2835, 1609, 1509, 1301, 1244, 1174, 1031, 830, 757, 693 cm−1. 1H NMR (400 MHz, Chloroform-d) δ 7.62−7.60 (m,1H), 7.54−7.50 (m,1H), 7.43−7.41 (m, 1H), 7.30−7.34 (m, 1H), 7.24−7.18 (m, 2H), 6.86−6.80 (m, 2H), 3.81 (s, 2H), 3.79 (s, 3H), 3.66 (s, 2H), 1.46 (d, J = 162.8 Hz, 1H). 13C NMR (100 MHz, CDCl3) δ 158.8, 142.6, 133.1, 132.8, 130.7, 130.1, 130.1, 129.5, 129.3, 127.5, 117.7, 114.1, 113.9, 112.7, 71.5, 55.4, 36.0, 34.1 ppm. HRMS (ESI) m/z: calcd for C16H15NONaS [M + Na]+ 292.0767, found: 292.0763. 5-((4-Methoxybenzyl)thio)pentanenitrile (3e). Yellow oil (92 mg, 78%). IR 2935, 2836, 1609, 1510, 1459, 1301, 1244, 1175, 1031, 832, 741 cm−1. 1H NMR (400 MHz, Chloroform-d) δ 7.22 (d, J = 8.6 Hz, 2H), 6.85 (d, J = 8.6 Hz, 2H), 3.80 (s, 3H), 3.67 (s, 2H), 2.43 (t, J = 6.6 Hz, 2H), 2.31 (t, J = 6.7 Hz, 2H), 1.76−1.66 (m, 4H). 13C NMR (100 MHz, CDCl3) δ 158.6, 130.1, 129.8, 119.4, 113.9, 55.2, 35.5, 30.0, 27.8, 24.3, 24.0, 16.7 ppm. HRMS (ESI) m/z: calcd for C13H17NONaS [M + Na]+ 258.0923, found: 258.0925.

Table 5. Substrate Scope of Diaryl Methanols and Triaryl Methanol Derivativesa

a

Reagents and conditions: 8 (0.5 mmol), Bunte salt (1.0 mmol), HCl (0.5 mmol, 36−38% in aqueous solution) in water (2 mL) at 100 °C for 12 h. bReagents and conditions: 8 (0.3 mmol), Bunte salt (0.6 mmol), HCl (0.3 mmol, 36-38% in aqueous solution) in water (2 mL) at 100 °C for 25 h.

Scheme 1. A Plausible Mechanism

carbocation and subsequently reacts with 4′ to afford the final unsymmetrical aryl sulfides.

3. CONCLUSION In summary, we have reported a simple one-pot synthesis of unsymmetrical aryl sulfides. A C−S−C bond was formed under aqueous conditions in the presence of alcohols, organohalides, and odorless sodium thiosulfate. A variety of aryl sulfides also are compatible to this reaction under aqueous conditions. 4. EXPERIMENTAL SECTION General Experimental Information. Unless otherwise stated, all reagents were purchased from commercial suppliers and used without further purification. Analytical thin-layer chromatography (TLC) was performed on silica gel, visualized by irradiation with UV light. For column chromatography, 300−400 mesh silica gel was used. All reactions were carried out in air and using undistilled solvent, without the need of precautions to exclude air and moisture unless otherwise noted. Melting points were recorded on an Electrothermal digital melting point apparatus and were uncorrected. IR spectra were recorded on a BRUKER VERTEX 70 spectrophotometer. 1H NMR and 13C NMR spectra were recorded on a BRUKER 400 MHz (1H NMR) and 100 MHz (13C NMR) spectrumeter using CDCl3 as solvent and biphenyl as internal standard. High-resolution mass spectra were obtained using BRUKER micrOTOF-Q III instrument with ESI source. General Procedure for the Three-Component Reactions of Compounds 3. Organohalide 1 (1.0 mmol), benzyl alcohol 2 (0.5 10177

DOI: 10.1021/acs.joc.7b01653 J. Org. Chem. 2017, 82, 10174−10180

Article

The Journal of Organic Chemistry N,N-Diethyl-2-((4-methoxybenzyl)thio)propenamide (3f). Colorless oil (52 mg, 37%). IR 2969, 2835, 1634, 1510, 1458, 1378, 1246, 1174, 1136, 1032, 832 cm−1. 1H NMR (400 MHz, Chloroform-d) δ 7.23 (d, J = 8.6 Hz, 2H), 6.86−6.82 (m, 2H), 3.79 (d, J = 1.8 Hz, 3H), 3.78−3.70 (m, 2H), 3.53−3.42 (m, 2H), 3.32−3.26 (m, 1H), 3.22− 3.16 (1H), 3.10−3.01 (1H), 1.51 (d, J = 6.7 Hz, 3H), 1.11 (t, J = 7.1 Hz, 3H), 1.04 (t, J = 7.2 Hz, 3H). 13C NMR (100 MHz, CDCl3) δ 170.7, 158.8, 130.3, 129.9, 114.0, 55.4, 42.0, 40.8, 37.9, 33.6, 18.2, 14.8, 13.1 ppm. HRMS (ESI) m/z: calcd for C15H24NO2S [M + H]+ 282.1522, found: 282.1522. 4-(((2-Methoxybenzyl)thio)methyl)benzonitrile (3g). White solid (73 mg, 54%). Mp 44.5−47.8 °C. IR 2835, 2361, 1560, 1492, 1288, 1093, 1027, 827, 747, 696 cm−1. 1H NMR (400 MHz, Chloroform-d) δ 7.60−7.55 (m, 2H), 7.41 (d, J = 8.1 Hz, 2H), 7.25−7.20 (m, 1H), 7.18−7.16 (m,1H), 6.92−6.90(m,1H), 6.88−6.85 (m, 1H), 3.81 (s, 3H), 3.68 (s, 2H), 3.65 (s, 2H). 13C NMR (100 MHz, CDCl3) δ 156.8, 143.9, 131.7, 129.8, 129.2, 128.1, 125.6, 120.0, 118.4, 110.2, 110.2, 54.9, 35.4, 29.7 ppm. HRMS (ESI) m/z: calcd for C16H15NONaS [M + Na]+ 292.0767, found: 292.0774. 5-(((3-Chlorobenzyl)thio)methyl)benzo[d][1,3]dioxole (3h). Yellow oil (91 mg, 62%). IR 2894, 1597, 1500, 1487, 1442, 1245, 1185, 1037, 926, 811, 690 cm−1. 1H NMR (400 MHz, Chloroform-d) δ 7.26 (t, J = 2.4 Hz, 2H), 7.22 (q, J = 1.6 Hz, 1H), 7.15 (m, 1H), 6.81 (d, J = 1.8 Hz, 1H), 6.73 (d, J = 7.9 Hz, 1H), 6.67 (m, 1H), 5.95 (s, 2H), 3.55 (s, 2H), 3.53 (s, 2H). 13C NMR (100 MHz, CDCl3) δ 147.4, 146.2, 139.8, 133.77, 131.8, 131.0, 129.2, 128.6, 126.7, 126.6, 121.7, 108.8, 107.5, 100.6, 76.9, 76.5, 76.2, 35.2, 34.5 ppm. HRMS (ESI) m/z: calcd for C15H13ClO2NaS [M + Na]+ 315.0217, found: 315.0229. 5-(((4-Methylbenzyl)thio)methyl)benzo[d][1,3]dioxole (3i). White solid (57 mg, 42%). Mp 50.1−52.3 °C. IR 3005, 2913, 1609, 1500, 1441, 1242, 1181, 1036, 923, 801 cm−1. 1H NMR (400 MHz, Chloroform-d) δ 7.24 (d, J = 8.0 Hz, 2H), 7.18 (d, J = 7.8 Hz, 2H), 6.88 (d, J = 1.6 Hz, 1H), 6.81−6.74 (m, 2H), 6.01 (s, 2H), 3.63 (s, 2H), 3.58 (s, 2H), 2.40 (s, 3H). 13C NMR (100 MHz, CDCl3) δ 147.9, 146.7, 136.7, 135.1, 132.1, 129.3, 129.0, 122.3, 109.4, 108.1, 101.1, 35.6, 35.4 ppm. HRMS (ESI) m/z: calcd for C16H16O2NaS [M + Na]+ 295.0763, found: 295.0761. 4-(((Benzo[d][1,3]dioxol-5-ylmethyl)thio)methyl)benzonitrile (5a). White solid (120 mg, 85%). Mp 56.4−57.3 °C. IR 2898, 1605, 1499, 1441, 1241, 1035, 922, 813, 744, 696 cm−1. 1H NMR (400 MHz, Chloroform-d) δ 7.62−7.56 (m, 2H), 7.37 (d, J = 8.1 Hz, 2H), 6.78 (d, J = 1.8 Hz, 1H), 6.72 (d, J = 7.9 Hz, 1H), 6.65−6.44 (m, 1H), 5.96 (s, 2H), 3.61 (s, 2H), 3.53 (s, 2H). 13C NMR (100 MHz, CDCl3) δ 148.0, 146.9, 144.1, 132.4, 131.2, 129.8, 122.2, 118.9, 110.9, 109.3, 108.1, 101.2, 35.9, 35.3 ppm. HRMS (ESI) m/z: calcd for C16H13NO2NaS [M + Na]+ 306.0559, found: 306.0552. 5-(((4-Chlorobenzyl)thio)methyl)benzo[d][1,3]dioxole (5b). White solid (145 mg, 99%). Mp 44.7−46.4 °C. IR 2894, 2776, 1597, 1501, 1443, 1245, 1186, 1037, 926, 811, 690 cm−1. 1H NMR (400 MHz, Chloroform-d) δ 7.35−7.31 (m, 2H), 7.26 (d, J = 8.4 Hz, 2H), 6.85 (d, J = 1.7 Hz, 1H), 6.78 (d, J = 7.9 Hz, 1H), 6.723−6.71 (m, 1H), 6.00 (s, 2H), 3.61 (s, 2H), 3.57 (s, 2H). 13C NMR (100 MHz, CDCl3) δ 147.98, 146.8, 136.8, 132.8, 131.7, 131.6, 130.4, 128.7, 122.3, 109.4, 108.1, 35.7, 34.9 ppm. HRMS (ESI) m/z: calcd for C15H14ClO2S [M + H]+ 293.0398, found: 298.0395. 5-(((4-Bromobenzyl)thio)methyl)benzo[d][1,3]dioxole (5c). White solid (145 mg, 98%). Mp 41.5−43.9 °C. IR 2909, 1482, 1441, 1360, 1242, 1188, 1096, 923, 804 cm−1. 1H NMR (400 MHz, Chloroform-d) δ 7.42 (d, J = 8.4 Hz, 2H), 7.15 (d, J = 8.4 Hz, 2H), 6.79 (d, J = 1.8 Hz, 1H), 6.73 (d, J = 7.9 Hz, 1H), 6.68−6.65 (m, 1H), 5.95 (s, 2H), 3.53 (s, 2H), 3.51 (s, 2H). 13C NMR (100 MHz, CDCl3) δ 147.1, 146.8, 137.4, 131.7, 130.8, 122.3, 120.9, 109.4, 108.1, 101.2, 35.7, 35.0 ppm. HRMS (ESI) m/z: calcd for C15H13BrO2NaS [M + Na]+ 358.9712, found: 358.9713. Ethyl 4-(((Benzo[d][1,3]dioxol-5-ylmethyl)thio)methyl)benzoate (5d). Yellow oil (126 mg, 76%). IR 2905, 1712, 1609, 1487, 1443, 1365, 1273, 1176, 1036, 926, 716 cm−1. 1H NMR (400 MHz, Chloroform-d) δ 7.99 (d, J = 8.3 Hz, 2H), 7.34 (d, J = 8.3 Hz, 2H), 6.80 (d, J = 1.7 Hz, 1H), 6.73 (d, J = 7.8 Hz, 1H), 6.68−6.65 (m,1H),

5.95 (s, 2H), 4.38 (q, J = 7.1 Hz, 2H), 3.62 (s, 2H), 3.51 (s, 2H), 1.40 (t, J = 7.1 Hz, 3H). 13C NMR (100 MHz, CDCl3) δ 166.5, 148.0, 146.8, 143.6, 131.6, 129.9, 129.3, 129.1, 122.3, 109.4, 108.1, 101.2, 61.1, 35.7, 35.3, 14.6 ppm. HRMS (ESI) m/z: calcd for C18H19O4S [M + H]+ 331.0999, found: 331.1001. 5-(((4-(Trifluoromethyl)benzyl)thio)methyl)benzo[d][1,3]dioxole (5e). Yellow oil (152 mg, 93%). IR 2907, 1617, 1498, 1484, 1243, 1067, 1035, 864, 803, 618 cm−1. 1H NMR (400 MHz, Chloroform-d) δ 7.62 (d, J = 8.0 Hz, 2H), 7.44 (d, J = 8.0 Hz, 2H), 6.86 (d, J = 1.7 Hz, 1H), 6.79 (d, J = 7.9 Hz, 1H), 6.724−6.71(m, 1H), 6.01 (s, 2H), 3.68 (s, 2H), 3.59 (s, 2H). 13C NMR (100 MHz, CDCl3) δ 147.4, 146.3, 142.0, 130.9, 128.8, 125.0, 124.9, 124.9, 124.8, 121.7, 108.7, 107.5, 100.6, 35.2, 34.6 ppm. 19F NMR (376 MHz, CDCl3) δ −62.43. HRMS (ESI) m/z: calcd for C16H13F3O2NaS [M + Na]+ 349.0481, found: 349.0478. 5-(((2-Bromobenzyl)thio)methyl)benzo[d][1,3]dioxole (5f). Yellow oil (143 mg, 85%). IR 2890, 2776, 1567, 1501, 1441, 1245, 1185, 1037, 926, 811, 737, 657 cm−1. 1H NMR (400 MHz, Chloroform-d) δ 7.62− 7.60 (m, 1H), 7.38−7.36 (m, 1H), 7.33−7.29 (m, 1H), 7.18−7.14 (m, 1H), 6.91 (s, 1H), 6.79 (d, J = 0.7 Hz, 2H), 6.00 (s, 2H), 3.80 (s, 2H), 3.67 (s, 2H). 13C NMR (100 MHz, CDCl3) δ 147.9, 146.8, 137.6, 133.2, 131.7, 130.8, 128.7, 127.5, 124.7, 122.3, 109.4, 108.1, 101.1, 36.2, 36.1 ppm. HRMS (ESI) m/z: calcd for C15H13BrO2NaS [M + Na]+ 360.9691, found: 360.9690. 5-((Benzylthio)methyl)benzo[d][1,3]dioxole (5g). Yellow oil (112 mg, 87%). IR 2893, 1602, 1487, 1442, 1359, 1245, 1095, 1037, 926, 698 cm−1. 1H NMR (400 MHz, Chloroform-d) δ 7.38−7.27 (m, 6H), 6.87 (d, J = 1.7 Hz, 1H), 6.79 (d, J = 7.9 Hz, 1H), 6.76−6.74 (m, 1H), 6.00 (s, 2H), 3.66 (s, 2H), 3.58 (s, 2H). 13C NMR (100 MHz, CDCl3) δ 147.9, 146.7, 138.3, 132.0, 129.1, 128.6, 127.1, 122.3, 109.4, 108.1, 101.2, 35.7 ppm. HRMS (ESI) m/z: calcd for C15H14O2NaS [M + Na]+ 281.0607, found: 281.0613. ethyl 4-((Benzo[d][1,3]dioxol-5-ylmethyl)thio)butanoate (5h). Yellow oil (69 mg, 49%). IR 2908, 1728, 1608, 1488, 1443, 1373, 1246, 1035, 925, 810 cm−1. 1H NMR (400 MHz, Chloroform-d) δ 6.88 (s, 1H), 6.77 (d, J = 1.0 Hz, 2H), 5.98 (s, 2H), 4.17 (q, J = 7.1 Hz, 2H), 3.67 (s, 2H), 2.49 (t, J = 7.2 Hz, 2H), 2.44 (t, J = 7.3 Hz, 2H), 1.93 (p, J = 7.3 Hz, 2H), 1.29 (t, J = 7.1 Hz, 3H). 13C NMR (100 MHz, CDCl3) δ 173.2, 147.9, 146.7, 132.2, 122.1, 109.3, 108.1, 101.1, 60.5, 36.1, 33.2, 30.6, 24.5 ppm. HRMS (ESI) m/z: calcd for C14H18O4NaS [M + Na]+ 305.0818, found: 305.0831. 4-((1-(4-Fluorophenyl)-3-phenylprop-2-ynylthio)methyl)benzonitrile (7a). White solid (61 mg, 57%). Mp 83.5−84.3 °C. IR 2985, 2901, 2230, 1605, 1505, 1410, 1218, 1066, 838, 750, 685 cm−1. 1 H NMR (400 MHz, CDCl3): δ 7.63−7.57 (m, 2H), 7.50−7.44 (m, 6H), 7.38−7.33 (m, 3H), 7.07−7.00 (m, 2H), 4.78 (s, 1H), 4.06 (d, J = 13.8 Hz, 1H), 3.84 (d, J = 13.8 Hz, 1H) ppm. 13C NMR (100 MHz, CDCl3): δ 163.7, 161.3, 143.6, 133.2, 133.2, 132.5, 131.9, 129.9, 129.9, 129.8, 128.9, 128.6, 122.5, 118.8, 115.9, 115.6, 111.2, 87.2, 86.3, 38.8, 36.5 ppm. 19F NMR (376 MHz, CDCl3): δ −113.7 ppm. HRMS (ESI) m/z: calcd for C23H16FNNaS [M + Na]+ 380.0880, found: 380.0867. 4-((1,3-Diphenylprop-2-ynylthio)methyl)benzonitrile (7b). Yellow oil (70 mg, 69%). IR 3029, 2921, 2227, 1603, 1487, 1448, 1203, 825, 755, 689 cm−1. 1H NMR (400 MHz, CDCl3): δ 7.61−7.57 (m, 2H), 7.52−7.44 (m, 6H), 7.38−7.32 (m, 5H), 7.32−7.27 (m, 1H), 4.81 (s, 1H), 4.06 (d, J = 13.8 Hz, 1H), 3.84 (d, J = 13.8 Hz, 1H) ppm. 13C NMR (100 MHz, CDCl3): δ 143.8, 137.5, 132.5, 132.0, 130.0, 128.9, 128.8, 128.6, 128.3, 128.2, 122.8, 119.0, 111.1, 87.1, 86.6, 39.6, 36.4 ppm. HRMS (ESI) m/z: calcd for C23H17NNaS [M + Na]+ 362.0974, found: 362.0977. 4-((1-Phenyl-3-p-tolylprop-2-ynylthio)methyl)benzonitrile (7c). Yellow oil (41 mg, 39%). IR 3027, 2920, 2227, 1604, 1412, 1177, 818, 759, 696 cm−1. 1H NMR (400 MHz, CDCl3): δ 7.61−7.56 (m, 2H), 7.51−7.44 (m, 4H), 7.38−7.32 (m, 4H), 7.31−7.27 (m, 1H), 7.15 (d, J = 7.9 Hz, 2H), 4.80 (s, 1H), 4.05 (d, J = 13.8 Hz, 1H), 3.83 (d, J = 13.7 Hz, 1H), 2.37 (s, 3H) ppm. 13C NMR (100 MHz, CDCl3): δ 143.8, 139.0, 137.6, 132.5, 131.8, 129.9, 129.3, 128.8, 128.2, 128.2, 119.6, 118.9, 111.0, 87.2, 85.8, 39.6, 36.4, 21.7 ppm. HRMS (ESI) m/z: calcd for C24H19NNaS [M + Na]+ 376.1130, found: 376.1114. 10178

DOI: 10.1021/acs.joc.7b01653 J. Org. Chem. 2017, 82, 10174−10180

The Journal of Organic Chemistry

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4-((3-(4-Methoxyphenyl)-1-phenylprop-2-ynylthio)methyl)benzonitrile (7d). Brown oil (53 mg, 48%). IR 2960, 2227, 1598, 1508, 1248, 1169, 1027, 830, 697 cm−1. 1H NMR (400 MHz, Chloroform-d) δ 7.61−7.57 (m, 2H), 7.51−7.44 (m, 4H), 7.42−7.39 (m, 2H), 7.37−7.32 (m, 2H), 7.31−7.27 (m, 1H), 6.89−6.84 (m, 2H), 4.80 (s, 1H), 4.05 (d, J = 13.8 Hz, 1H), 3.84 (d, J = 7.1 Hz, 4H). 13C NMR (100 MHz, CDCl3): δ 160.0, 143.8, 137.7, 133.3, 132.4, 129.9, 128.8, 128.2, 118.9, 114.8, 114.2, 114.0, 111.0, 87.0, 85.1, 55.5, 39.6, 36.4 ppm. HRMS (ESI) m/z: calcd for C24H19NNaOS [M + Na]+ 392.1080, found: 392.1082. (E)-4-((1,3-Bis(4-bromophenyl)allylthio)methyl)benzonitrile (7e). Yellow oil (91 mg, 61%). IR 2987, 2919, 2227, 1605, 1485, 1070, 1008, 964, 811 cm−1. 1H NMR (400 MHz, CDCl3): δ 7.62−7.58 (m, 2H), 7.48−7.42 (m, 4H), 7.37 (d, J = 8.3 Hz, 2H), 7.24−7.18 (m, 4H), 6.35−6.25 (m, 2H), 4.37 (d, J = 7.0 Hz, 1H), 3.73−3.60 (m, 2H) ppm. 13C NMR (100 MHz, CDCl3): δ 143.8, 138.7, 135.1, 132.6, 132.2, 132.0, 131.2, 129.9, 129.8, 129.2, 128.2, 122.1, 121.9, 118.9, 111.2, 51.4, 36.1 ppm. HRMS (ESI) m/z: calcd for C23H17Br2NNaS [M + Na]+ 519.9341, found: 519.9335. (E)-4-((2-Methyl-1,3-diphenylallylthio)methyl)benzonitrile (7f). Yellow oil (80 mg, 75%). IR 3055, 2918, 2227, 1604, 1491, 1447, 843, 742, 696 cm−1. 1H NMR (400 MHz, CDCl3): δ 7.59 (d, J = 8.2 Hz, 2H), 7.40 (d, J = 8.2 Hz, 2H), 7.35−7.30 (m, 7H), 7.27−7.21 (m, 3H), 6.58 (s, 1H), 4.43 (s, 1H), 3.75−3.63 (m, 2H), 1.82 (d, J = 1.1 Hz, 3H) ppm. 13C NMR (100 MHz, CDCl3): δ 144.1, 139.3, 136.8, 132.5, 130.0, 129.2, 128.7, 128.4, 128.4, 127.7, 127.0, 58.5, 36.1, 15.8 ppm. HRMS (ESI) m/z: calcd for C24H21NNaS [M + Na]+ 378.1287, found: 378.1274. 4-((Benzhydrylthio)methyl)benzonitrile (9a). Yellow solid (69 mg, 44%). Mp 87.8−89.7 °C.IR 3676, 2987, 2923, 2226, 1732, 1602, 1490, 1080, 822, 704, 628 cm−1. 1H NMR (400 MHz, Chloroform-d) δ 7.63 (d, J = 8.3 Hz, 2H), 7.44−7.26 (m, 12H), 4.96 (s, 1H), 3.64 (s, 2H). 13 C NMR (100 MHz, CDCl3) δ 143.9, 140.5, 132.4, 129.8, 128.8, 128.5, 127.6, 118.9, 111.0, 77.5, 77.2, 76.8, 53.7, 36.6 ppm. HRMS (ESI) m/z: calcd for C21H18NS [M + H]+ 316.1154, found: 316.1166. 2-(Benzhydrylthio)-N,N-diethylpropanamide (9b). Yellow oil (72 mg, 44%). IR 2971, 2929, 1725, 1635, 1491, 1449, 1429, 1096, 748, 698, 616 cm−1. 1H NMR (400 MHz, Chloroform-d) δ 7.48 (d, 4H), 7.32 (m, 6H), 5.33 (s, 1H), 3.47 (m, 2H), 3.17 (m, 2H), 2.96 (m, 1H), 1.52 (s, 1H), 1.31 (s, 1H), 1.26 (s, 1H), 1.12 (t, J = 7.1 Hz, 3H), 0.96 (t, J = 7.2 Hz, 3H). 13C NMR (100 MHz, CDCl3) δ 170.1, 141.1, 140.5, 128.0, 128.0, 127.8, 126.8, 126.7, 52.4, 41.3, 40.3, 39.1, 18.0, 14.06, 12.5 ppm. HRMS (ESI) m/z: calcd for C20H26NOS [M + H]+ 328.1730, found: 328.1744. 4-(((Bis(4-methoxyphenyl)methyl)thio)methyl)benzonitrile (9d). Gray solid (156 mg, 83%). Mp 120.8−122.7 °C. IR 2987, 2968, 2910, 1604, 1505, 1418, 1246, 1029, 813, 791 cm−1. 1H NMR (400 MHz, Chloroform-d) δ 7.63 (d, J = 8.0 Hz, 2H), 7.32 (m, 6H), 6.89 (d, J = 8.7 Hz, 4H), 4.89 (s, 1H), 3.84 (s, 6H), 3.61 (s, 2H). 13C NMR (100 MHz, CDCl3) δ 158.3, 143.5, 132.2, 131.8, 131.7, 129.2, 128.9, 118.4, 113.5, 113.0, 110.2, 54.8, 51.8, 36.0 ppm. HRMS (ESI) m/z: calcd for C23H22NO2S [M + H]+ 376.1366, found: 376.1380. 4-((Tritylthio)methyl)benzonitrile (9e). White solid (190 mg, 97%). Mp 97.8−101.9 °C. IR 2989, 2864, 2232, 1727, 1605, 1448, 1278, 1081, 772, 668 cm−1. 1H NMR (400 MHz, Chloroform-d) δ 7.45 (m, 8H), 7.29 (t, J = 7.5 Hz, 6H), 7.22 (t, J = 7.2 Hz, 3H), 7.14 (d, J = 7.9 Hz, 2H), 3.36 (s, 2H). 13C NMR (100 MHz, CDCl3) δ 143.8, 142.6, 131.7, 129.3, 129.1, 127.6, 126.5, 118.3, 110.2, 76.9, 76.6, 76.3, 67.4, 36.2 ppm. HRMS (ESI) m/z: calcd for C27H22NS [M + H]+ 392.1467, found: 392.1476.

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*E-mail: [email protected]. *E-mail: [email protected]. ORCID

Shun-Yi Wang: 0000-0002-8985-8753 Shun-Jun Ji: 0000-0002-4299-3528 Notes

The authors declare no competing financial interest.

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ACKNOWLEDGMENTS We gratefully acknowledge the National Natural Science Foundation of China (21772137, 21672157, 21372174), the Major Basic Research Project of the Natural Science Foundation of the Jiangsu Higher Education Institutions (no. 16KJA150002), PAPD, and Soochow University for financial support and State and Local Joint Engineering Laboratory for Novel Functional Polymeric Materials.

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REFERENCES

(1) (a) Block, E. Angew. Chem., Int. Ed. Engl. 1992, 31, 1135. (b) Ranjan, J. Int. J. Health Care Qual. Assur. 2009, 22, 82. (c) Laroche, C.; Li, J.; Kerwin, S. M. J. Med. Chem. 2011, 54, 5059. (d) Saito, K.; Kondo, K.; Akiyama, T. Org. Lett. 2015, 17, 3366. (2) (a) Smith, B. R.; Eastman, C. M.; Njardarson, J. T. J. Med. Chem. 2014, 57, 9764. (b) Haklai, R.; Weisz, M. G.; Elad, G.; Paz, A.; Marciano, D.; Egozi, Y.; Ben-Baruch, G.; Kloog, Y. Biochemistry 1998, 37, 1306. (3) (a) Lin, D.-Y.; Zhang, S.-Z.; Block, E.; Katz, L. C. Nature 2005, 434, 470. (b) Joyce, N. I.; Eady, C. C.; Silcock, P.; Perry, N. B.; Van Klink, J. W. J. Agric. Food Chem. 2013, 61, 1449. (c) White, N. J. J. Clin. Invest. 2004, 113, 1084. (4) (a) Ilardi, E. A.; Vitaku, E.; Njardarson, J. T. J. Med. Chem. 2014, 57, 2832. (b) Winstanley, P. A.; Ward, S. A.; Snow, R. W. Microbes Infect. 2002, 4, 157. (5) (a) Takimiya, K.; Osaka, I.; Mori, T.; Nakano, M. Acc. Chem. Res. 2014, 47, 1493. (b) Mishra, A.; Ma, C.-Q.; Bauerle, P. Chem. Rev. 2009, 109, 1141. (c) Meng, L.-K.; Fujikawa, T.; Kuwayama, M.; Segawa, Y.; Itami, K. J. Am. Chem. Soc. 2016, 138, 10351. (6) (a) Nair, D. P.; Podgórski, M.; Chatani, S.; Gong, T.; Xi, W.-X.; Fenoli, C. R.; Bowman, C. N. Chem. Mater. 2014, 26, 724. (b) Seto, H.; Takara, M.; Yamashita, C.; Murakami, T.; Hasegawa, T.; Hoshino, Y.; Miura, Y. ACS Appl. Mater. Interfaces 2012, 4, 5125. (7) (a) Fieser, M. E.; Johnson, C. W.; Bates, J. E.; Ziller, J. W.; Furche, F.; Evans, W. J. Organometallics 2015, 34, 4387. (b) Roy, S.; Schurmann, C. J.; Mondal, T.; Koley, D.; Herbst-Irmer, R.; Stalke, D.; Roesky, H. W. Chem. - Eur. J. 2016, 22, 12629. (c) Li, J.-Q.; Li, F.-W.; Koh, L. L.; Hor, T. S. A. Dalton Trans. 2010, 39, 2441. (d) Mellah, M.; Voituriez, A.; Schulz, E. Chem. Rev. 2007, 107, 5133. (8) (a) Modha, S. G.; Mehta, V. P.; Van der Eycken, E. V. Chem. Soc. Rev. 2013, 42, 5042. (b) Adam, W.; Bargon, R. M.; Schenk, W. A. J. Am. Chem. Soc. 2003, 125, 3871. (c) Wang, K.; Groom, M.; Sheridan, R.; Zhang, S.; Block, E. J. Sulfur Chem. 2013, 34, 55. (9) (a) Raban, M.; Chern, L. J. J. Org. Chem. 1980, 45, 1688. (b) Bottino, F.; Fradullo, R.; Pappalardo, S. J. Org. Chem. 1981, 46, 2793. (c) Koval, I. V. Russ. Chem. Rev. 1995, 64, 731. (d) Qiao, Z.-J.; Wei, J.-P.; Jiang, X.-F. Org. Lett. 2014, 16, 1212. (10) (a) Kondo, T.; Mitsudo, T. Chem. Rev. 2000, 100, 3205. (b) Beletskaya, I. P.; Ananikov, V. P. Chem. Rev. 2011, 111, 1596. (c) Percec, V.; Bae, J. Y.; Hill, D. H. J. Org. Chem. 1995, 60, 6895. (d) Murata, M.; Buchwald, S. L. Tetrahedron 2004, 60, 7397. (e) Eichman, C. C.; Stambuli, J. P. J. Org. Chem. 2009, 74, 4005. (f) Itoh, T.; Mase, T. Org. Lett. 2004, 6, 4587. (g) Beletskaya, I. P.; Ananikov, V. P. Eur. J. Org. Chem. 2007, 2007, 3431. (11) (a) Fu, Y.; Xu, Q.-S.; Li, Q.-Z.; Du, Z.-Y.; Wang, K.-H.; Huang, D.-F.; Hu, Y.-L. Org. Biomol. Chem. 2017, 15, 2841. (b) He, W.; Wang,

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The Journal of Organic Chemistry Z.-M.; Li, X.-J.; Yu, Q.; Wang, Z.-W. Tetrahedron 2016, 72, 7594. (c) Silva-Cuevas, C.; Perez-Arrieta, C.; Polindara-Garcia, L. A.; LujanMontelongo, J. A. Tetrahedron Lett. 2017, 58, 2244. (12) (a) La Regina, G.; Gatti, V.; Famiglini, V.; Piscitelli, F.; Silvestri, R. ACS Comb. Sci. 2012, 14, 258. (b) Ge, W.; Wei, Y. Green Chem. 2012, 14, 2066. (c) Zou, L.-H.; Reball, J.; Mottweiler, J.; Bolm, C. Chem. Commun. 2012, 48, 11307. (d) Azeredo, J. B.; Godoi, M.; Martins, G. M.; Silveira, C. C.; Braga, A. L. J. Org. Chem. 2014, 79, 4125. (e) Xiao, X.; Feng, M.-H.; Jiang, X.-F. Angew. Chem., Int. Ed. 2016, 55, 14121. (13) (a) Qi, H.; Zhang, T.-X.; Wan, K.-F.; Luo, M.-M. J. Org. Chem. 2016, 81, 4262. (b) Tu, H.-Y.; Hu, B.-L.; Deng, C.-L.; Zhang, X.-G. Chem. Commun. 2015, 51, 15558. (c) Terada, M.; Ota, Y.; Li, F.; Toda, Y.; Kondoh, A. J. Am. Chem. Soc. 2016, 138, 11038. (d) Mao, J.-Y.; Jia, T.-Z.; Frensch, G.; Walsh, P. J. Org. Lett. 2014, 16, 5304. (14) (a) Beletskaya, I. P.; Ananikov, V. P. Eur. J. Org. Chem. 2007, 2007, 3431. (b) Kondo, T.; Mitsudo, T. Chem. Rev. 2000, 100, 3205. (c) Dondoni, A.; Marra, A. Eur. J. Org. Chem. 2014, 2014, 3955. (d) Rodygin, K. S.; Ananikov, V. P. Green Chem. 2016, 18, 482. (e) Khatik, G. L.; Kumar, R.; Chakraborti, A. K. Org. Lett. 2006, 8, 2433. (f) Honeker, R.; Garza-Sanchez, R. A.; Hopkinson, M. N.; Glorius, F. Chem. - Eur. J. 2016, 22, 4395. (g) Lin, Y.-M.; Lu, G.-P.; Cai, C.; Yi, W.-B. RSC Adv. 2015, 5, 27107. (15) (a) Yang, L.-F.; Liu, C.-G.; Xu, X.-P.; Ji, S.-J. Org. Biomol. Chem. 2016, 14, 2993. (b) Chu, X.-Q.; Meng, H.; Xu, X.-P.; Ji, S.-J. Chem. Eur. J. 2015, 21, 11359. (c) Gu, Z.-Y.; Cao, J.-J.; Wang, S.-Y.; Ji, S.-J. Chem. Sci. 2016, 7, 4067. (d) Li, J.; Cai, Z.-J.; Wang, S.-Y.; Ji, S.-J. Org. Biomol. Chem. 2016, 14, 9384. (16) Chu, X.-Q.; Xu, X.-P.; Ji, S.-J. Chem. - Eur. J. 2016, 22, 14181. (17) (a) Zhou, C.; Fu, C.-L.; Ma, S.-M. Angew. Chem., Int. Ed. 2007, 46, 4379. (b) Li, J.-X.; Li, C.-S.; Yang, S.-R.; An, Y.-N.; Wu, W.-Q.; Jiang, H.-F. J. Org. Chem. 2016, 81, 2875. (c) Qiao, Z.-J.; Jiang, X.-F. Org. Biomol. Chem. 2017, 15, 1942.

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