Supporting Information

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1 Supporting Information Synthesis of Ortho-Aryloxy Triarylsulfonium Salts via Aryne Insertion into Diaryl Sulfoxides Xiaojin Li, Yan Sun, Xin Huang, Lei Zhang, Lichun Kong, Bo Peng*,, Department of Chemistry, Zhejiang Normal University, 688 Yingbin Road, Jinhua , China State Key Laboratory of Fine Chemicals, Dalian University of Technology, Dalian , China Table of Contents Contents 1 General information Preparation of starting materials Optimization of reaction conditions Reactions of aryne precursor 1a with various aryl sulfoxides Reactions of aryne precursors with aryl sulfoxides Study of the H 2 O influence on the reaction Labeling and control experiments Descriptive example for large scale reaction (3 mmol) NMR spectra

2 1 General information Unless otherwise indicated, all glassware was oven dried by a heat gun before use and all reactions were performed under an atmosphere of Nitrogen. All solvents were distilled from appropriate drying agents prior to use. All reagents were used as received from commercial suppliers unless otherwise stated. Reaction progress was monitored by thin layer chromatography (TLC) performed on plastic plates coated with silica gel GF254 with 0.2 mm thickness. Chromatograms were visualized by fluorescence quenching with UV light at 254 nm or by staining using potassium permanganate. Flash column chromatography was performed using silica gel 60 ( mesh). Neat infra-red spectra were recorded using a NEXUS670 FT-IR spectrometer. Wavelengths (ν) are reported in cm -1. Mass spectra were obtained using a TOF MS instrument ESI source. All 1 H NMR, 13 C NMR spectra were recorded on Bruker AV-400 or AV-600. Chemical shifts were given in parts per million (ppm, δ), referenced to the solvent peak of CDCl 3, defined at δ = ( 13 C NMR). Coupling constants were quoted in Hz(J). 1 H NMR Spectroscopy splitting patterns were designated as singlet (s), doublet (d), triplet (t),quadruplet (q), pentet (p), septet (se), octet (o). Splitting patterns that could not be interpreted or easily visualized were designated as multiplet (m). 2 Preparation of starting materials 2.1 Preparation of aryne precursors Aryne precursors 1a 1, 1b 2, 1c 3 and 1d 4 are known in literatures. We prepared these compounds following the procedures shown below. [1] Shen, C.; Yang, G.; Zhang, W. Org. Lett. 2013, 15, [2] Rossini, A. F. C.; Muraca, A. C. A.; Casagrande, G. A.; Raminelli, C. J. Org. Chem. 2015, 80, [3] Biju, A. T.; Glorius, F. Angew. Chem., Int. Ed. 2010, 49, [4] Pen a, D.; Pérez, D.; Guitián, E.; Castedo, L. J. Am. Chem. Soc. 1999, 121,

3 2-(trimethylsilyl)phenyl trifluoromethanesulfonate (1a): Step a: A mixture of 2-bromophenol (3.4 ml, 28.9 mmol) and 1,1,1,3,3,3-hexamethyl-disilazane (HMDS, 7.8 ml, 37.6 mmol) in THF(100 ml) was stirred at 80 C under nitrogen atmosphere for 40 h. Then, the volatile substances were removed under reduced pressure, affording the crude product as a yellow oil, which was used without further purification. Step b:to a solution of the obtained crude material in THF (70 ml) was added n-buli (13.9 ml, 2.5 M, 34.7 mmol) at -78 C. After stirring under the same temperature for 30 min, to the mixture was added Tf 2 O (5.8 ml, 34.7 mmol) in a dropwise manner. The mixture was stirred for another 30 min under the same temperature. Then it was warmed to room temperature and stirred for 20 min. After that, the mixture was quenched with NaHCO 3 (aq.). The aqueous layer was extracted with ethyl acetate (3 40 ml). The combined organic layers were dried over anhydrous Na 2 SO 4, filtered, and concentrated under reduced pressure. After removal of the solvent in vacuo, the crude material was purified by flash column chromatography on silica gel to give the title compound as a light yellow oil, 4.76 g, 55% yield. (Rf = 0.60, eluent: petroleum ether) 1 H NMR (600 MHz, CDCl 3 ): δ (m, 1H), (m, 1H), (m, 2H), 0.38 (s, 9H). The 1 H NMR of 1a is consistent with the reported spectra 1. 3-methoxy-2-(trimethylsilyl)phenyl trifluoromethanesulfonate (1b): 3

4 Step a: A mixture of 3-methoxyphenol (4.4 ml, 40 mmol) and HMDS (12.5 ml, 60 mmol) was stirred at 80 C under nitrogen atmosphere for 3 h. Then, the volatile substances were removed under reduced pressure, affording the crude product as a yellow oil, which was used without further purification. Step b: To a solution of the obtained crude product in THF (60 ml) was added LDA (80 ml, 44 mmol, 0.55 M in THF) dropwise at 78 C under nitrogen atmosphere. The mixture was then warmed to room temperature and stirred for 90 min. After cooled to 78 C again, to the mixture was added TMSCl (6.1 ml, 48 mmol). The mixture was then warmed to room temperature and stirred for 18 h. Afterwards, the mixture was quenched with NH 4 Cl (sat. aqueous solution). The aqueous layer was extracted with ethyl acetate (3 50 ml). The combined organic layers were dried over anhydrous Na 2 SO 4. After filtration, the solvent was evaporated under reduced pressure. The obtained residue was purified by column chromatography on silica gel, affording desired product as colorless oil, 7.95 g, 74% yield. (Rf = 0.35, eluent: petroleum ether). Step c: To a solution of (3-Methoxy-2-(trimethylsilyl)phenoxy)trimethylsilane (4.51 g, 16.8 mmol) in THF (42 ml) was added TBAF (19.31 ml, 0.87 M solution in THF, 16.8 mmol) dropwise at room temperature. After stirred for 30 min, the mixture was filtered through a short plug of silica gel, and the residue was washed with PE/EtOAc (10:1). Concentration of the mixture in vacuo gave the title compound as a colorless oil, 2.47 g, 75% yield. (Rf = 0.54, eluent: PE/EtOAc = 10/1). Step d: To a solution of 3-methoxy-2-(trimethylsilyl)phenol (2.47 g, 12.6 mmol) in CH 2 Cl 2 (58 ml) was added Et 3 N (2.0 ml,13.9 mmol) dropwise at -78 C. After stirring for 30 min, Tf 2 O (2.3 ml, 13.9 mmol) was added dropwise and then stirred for 30 min under the same temperature. Then the mixture was gradually warmed to room temperature. After stirring for 1 h, NaHCO 3 (cold sat. aqueous solution) and H 2 O were sequentially added to the mixture. The aqueous layer was extracted with CH 2 Cl 2 (3 35 ml). The combined organic layers were dried over Na 2 SO 4, filtered, and concentrated in vacuo. The obtained residue was purified by flash column chromatography on silica gel to afford the title compound 1b as yellow oil, 2.73 g, 66% yield. (Rf = 0.30, petroleum ether). 1 H NMR (400 MHz, CDCl 3 ): δ 7.37 (t, J = 8.3 Hz, 1H), 6.95 (d, J = 8.4 Hz, 1H), 6.84 (d, J = 8.3 Hz, 1H), 3.83 (s, 3H), 0.38 (s, 9H). The 1 H NMR of 1b is consistent with the reported spectra 2. 4

5 6-(trimethylsilyl)benzo[d][1,3]dioxol-5-yl trifluoromethanesulfonate (1c): Step a: To a cooled (0 C ) solution of sesamol (5.0 g, 36.2 mmol) in AcOH (11 ml) was added a solution of bromine (1.5 ml, 29.0 mmol) in AcOH (6.3 ml) dropwise over 15 minutes. The mixture was then rapidly poured onto ice. The resulting green solid was collected by filtration, washed copiously with water and extracted with ethyl acetate (3 35 ml). The combined organic layers were dried over anhydrous Na 2 SO 4, filtered, and concentrated under reduced pressure to afford the crude product as a dull green solid (3.99 g, 51 %), which was used without further purification. Step b: A mixture of the obtained crude product and HMDS (2.9 ml, 13.9 mmol) in THF (38 ml) was refluxed for 4 h. The solvent was evaporated under reduced pressure, and the residue was subjected to high vacuum to remove excess NH 3 and unreacted HMDS. The resulted crude product was used without further purification. Step c: To a solution of the obtained crude product in THF (41 ml) was added n-buli (6.1 ml, 2.5 M, in THF, 15.3 mmol) dropwise at -78 C. After stirring for 30 min, Tf 2 O (2.8 ml, 16.7 mmol) was then added dropwise to the mixture. The mixture was then stirred for 30 min under the same temperature. Then the mixture was warmed to room temperature and stirred for 20 min. After that, NaHCO 3 (cold sat. aqueous solution) and H 2 O were sequentially added to the mixture. The aqueous layer was extracted with ethyl acetate (3 30 ml), the combined organic layers were dried over Na 2 SO 4, filtrated and concentrated in vacuo. The crude material was purified by flash column chromatography on silica gel to afford the title compound 1c as light yellow oil, 4.35 g, 91% yield. (Rf = 0.25, eluent: petroleum ether) 1 H NMR (600 MHz, CDCl 3 ): δ 6.87 (d, J = 20.9 Hz, 2H), 6.03 (s, 2H), 0.34 (s, 9H). The 1 H NMR of 1c is consistent with the reported spectra 3. 5

6 4,5-difluoro-2-(trimethylsilyl)phenyl trifluoromethanesulfonate (1d): Step a: A mixture of 2-bromo-4,5-difluorophenol (1.1 ml, 10 mmol) and HMDS (2.3 ml, 11 mmol) in THF (30mL) was refluxed for 3 h. The solvent was evaporated under reduced pressure and the residue was subjected to high vacuum to remove excess NH 3 and unreacted HMDS. The resulted crude product was used without further purification. Step b: To a solution of the obtained crude product in THF (65 ml) was added n-buli (4.8 ml, 12.0 mmol, 2.5 M in THF) dropwise at 78 C. After stirring for 30 min, Tf 2 O (2.2 ml, 13 mmol) was added dropwise to the mixture which was stirred for another 30 min at the same temperature. Then, the mixture was warmed to room temperature and stirred for 20 min. After that, NaHCO 3 (cold sat. aqueous solution) and H 2 O were sequentially added to the mixture. The aqueous layer was extracted with ethyl acetate (3 20 ml), the combined organic layers were dried over Na 2 SO 4, filtrated and concentrated in vacuo. The crude material was purified by flash column chromatography on silica gel to afford the title compound 1d as a yellow oil, 2.52 g, 75% yield. (Rf = 0.70, eluent: petroleum ether) 1 H NMR (600 MHz, CDCl 3 ): δ 7.30 (t, J = 9.5 Hz, 1H), (m, 1H), 0.37 (s, 9H). The 1 H NMR of 1d is consistent with the reported spectra Preparation of aryl sulfoxides Diaryl sulfoxides 2a, 2c, 2f are commercially available. Diaryl sulfoxides 2b 5,6, 2d 6-8, 2e 9, 2g 10, 2h 5,11, 2i 6,12, 2j 5,13, 2k 5,14, 2l 15, 2m 16, 2n 17, 2o 18, 2p 19 are known in literatures. We prepared commercially unavailable diaryl sulfoxides 2b, 2d, 2e, 2g-2p following the procedures shown below. [5] Bandgar, B. P.; Makone, S. S. Synth. Commun. 2004, 34, 743. [6] Bhilare, S. V.; Deorukhkar, A. R.; Darvatkar, N. B.; Rasalkar, M. S.; Salunkhe, M. M. Journal of Molecular Catalysis A: Chemical 2007, 270, 123. [7] Mohile, S. S.; Potdar, M. K.; Salunkhe, M. M. Tetrahedron Lett. 2003, 44, [8] Olah, G. A.; Marinez, E. R.; Surya Prakash, G. K. Synlett 1999,

7 [9] Xu, H.-J.; Lin, Y.-C.; Wan, X.; Yang, C.-Y.; Feng, Y.-S. Tetrahedron 2010, 66, [10] Jeon, H. B.; Kim, K. T.; Kim, S. H. Tetrahedron Lett. 2014, 55, [11] Yadav, J. S.; Subba Reddy, B. V.; Rao, R. S.; Praveen kumar, S.; Nagaiah, K. Synlett 2002, 784. [12] Bandgar, B. P.; Kinkar, S. N.; Kamble, V. T.; Bettigeri, S. V. Synlett 2003, [13] Mohile, S. S.; Potdar, M. K.; Salunkhe, M. M. Tetrahedron Lett. 2003, 44, [14] Laali, K. K.; Nagvekar, D. S. J. Org. Chem. 1991, 56, [15] Gelat, F.; Lohier, J.-F.; Gaumont, A.-C.; Perrio, S. Adv. Synth. Catal. 2015, 357, [16] Hampel, T.; Ruppenthal, S.; Sälinger, D.; Brückner, R. Chem. Eur. J. 2012, 18, [17] Kirihara, M.; Yamamoto, J.; Noguchi, T.; Itou, A.; Naito, S.; Hirai, Y. Tetrahedron 2009, 65, [18] Jia, T.; Bellomo, A.; Montel, S.; Zhang, M.; El Baina, K.; Zheng, B.; Walsh, P. J. Angew. Chem., Int. Ed. 2014, 53, 260. [19] Eberhart, A. J.; Shrives, H. J.; Álvarez, E.; Carrër, A.; Zhang, Y.; Procter, D. J. Chem. Eur. J. 2015, 21, ,4'-sulfinylbis(methoxybenzene) (2b): Procedure: To a solution of SOCl 2 (0.6 ml, 8.2 mmol) in a 50 ml Schlenk flask was added anisole (20 ml) and TfOH (3.1 ml, 35.3 mmol) at 0 C. The in situ formed HCl was vented through the stop cock of the Schlenk flask. After 1 h, the mixture was gradually warmed to room temperature and stirred for 2 h. The mixture was then poured into ice and neutralized with NaHCO 3 (aq.). The aqueous layer was extracted with CH 2 Cl 2 (3 15 ml). The combined organic layers were dried over anhydrous Na 2 SO 4, filtered and concentrated under reduced pressure. The obtained residue was purified by flash column chromatography on silica gel to afford the title compound 2b as a white solid, mg, 21% yield. (Rf = 0.27, eluent: PE/EtOAc = 1/1) 1 H NMR (400 MHz, CDCl 3 ): δ 7.53 (d, J = 8.8 Hz, 4H), 6.95 (d, J = 8.8 Hz, 4H), 3.82 (s, 6H). 7

8 13 C NMR (101 MHz, CDCl 3 ): δ 161.8, 126.9, , b is a known compound 5,6. 4,4''-sulfinyldi-1,1'-biphenyl (2d): Procedure: Following a similar procedure for the synthesis of 2b, the title compound 2d was obtained as a white solid, 2.12 g, 73% yield. (Rf = 0.35, eluent: PE/EtOAc = 4/1) 1 H NMR (600 MHz, CDCl 3 ): δ (m, 4H), (m, 4H), (m, 4H), (m, 4H), (m, 2H). 13 C NMR (151 MHz, CDCl 3 ): δ 144.3, 144.2, 139.7, 128.9, 128.1, 128.1, 127.2, The 2d is a known compound chloro-4-(p-tolylsulfinyl)benzene (2e): Step a:a mixture of p-toluenethiol (1.99 g, 16 mmol), chloro-4-iodobenzene (3.82 g, 16 mmol), n-bu4nbr (0.52 g, 1.60 mmol) and NaOH (1.28 g, 32 mmol) and CuI (305 mg, 1.6 mmol) in toluene (11 ml) was stirred under reflux for 22 h. Then, the mixture was cooled to room temperature. Afterwards, a saturated aqueous solution of NH 4 Cl was added to the mixture. The aqueous layer was extracted with ethyl acetate (3 25 ml). The combined organic phase was dried over anhydrous Na 2 SO 4. After filtration, the mixture was concentrated under reduced pressure and recrystallized to afford the thioether as a yellow solid, 2.47 g, 66% yield. 8

9 Step b: To a solution of (4-chlorophenyl)(p-tolyl)sulfane (1.64 g, 7 mmol) in CH 2 Cl 2 (24 ml) in CH 2 Cl 2 (24 ml) was added m-cpba (1.33 g, 7.7 mmol) slowly at 0 C. The mixture was stirred at 0 C for 4 h. Then the mixture was gradually warmed to room temperature and stirred overnight. After that, the mixture was quenched with NaHCO 3 (sat. aqueous solution). The aqueous layer was then extracted with CH 2 Cl 2 (3 10 ml). The combined organic layers were washed with brine, dried over Na 2 SO 4, filtrated and concentrated in vacuo. The obtained residue was purified by column chromatography on silica gel to afford the title compound 2e as a white solid, 1.61 g, 92% yield. (Rf = 0.41, eluent: PE/EtOAc = 3/1) 1 H NMR (600 MHz, CDCl 3 ): δ 7.56 (d, J = 8.6 Hz, 2H), 7.51 (d, J = 8.2 Hz, 2H), 7.43 (d, J = 8.5 Hz, 2H), 7.27 (d, J = 9.2 Hz, 2H), 2.37 (s, 3H). 13 C NMR (151 MHz, CDCl 3 ): δ 144.4, 142.0, 137.1, 130.2, 129.5, 126.0, 124.9, The 1 H NMR and 13 C NMR of 2e are consistent with the reported spectra 9. dimethyl 4,4'-sulfinyldibenzoate (2g) Step a:a mixture of methyl 4-iodobenzoate (2.62 g, 10 mmol), CS 2 (0.6 ml, 10 mmol), DBU (3.0 ml, 20 mmol) and CuI (0.19 g, 1 mmol) in toluene (15 ml) was stirred under 100 C for 12 h. Then, the mixture was cooled to room temperature. Afterwards, 25 ml H 2 O was added to the mixture. The aqueous layer was extracted with ethyl acetate (3 25 ml). The combined organic phase was dried over anhydrous Na 2 SO 4. After filtration, the mixture was concentrated under reduced pressure and the obtained residue was purified by column chromatography on silica gel to afford the dimethyl 4,4'-thiodibenzoate as a white solid, 528 g, 35% yield. 9

10 Step b: To a solution of dimethyl 4,4'-thiodibenzoate (514 mg, 1.7 mmol) in CH 2 Cl 2 (5.5 ml) in CH 2 Cl 2 (5.5 ml) was added m-cpba (328 mg, 1.9 mmol) slowly at 0 C. The mixture was stirred at 0 C for 1 h. Then the mixture was gradually warmed to room temperature and stirred for 6 h. After that, the mixture was quenched with NaHCO 3 (sat. aqueous solution). The aqueous layer was then extracted with CH 2 Cl 2 (3 5 ml). The combined organic layers were washed with brine, dried over Na 2 SO 4, filtrated and concentrated in vacuo. The obtained residue was purified by column chromatography on silica gel to afford the title compound 2g as a white solid, 296 mg, 53% yield. (Rf = 0.36, eluent: PE/EtOAc = 3/1) 1 H NMR (600 MHz, CDCl 3 ): δ 8.12 (d, J = 8.5 Hz, 4H), 7.73 (d, J = 8.5 Hz, 4H), 3.91 (s, 6H). The 2g is a known compound 10. 4,4'-sulfinylbis(1,2-dimethylbenzene) (2h): Procedure: Following a similar procedure for the synthesis of 2b, the title compound 2h was obtained as a light yellow solid, 1.24 g, 59% yield. (Rf = 0.3, eluent: PE/EtOAc = 4/1) 1 H NMR (600 MHz, CDCl 3 ): δ 7.40 (s, 2H), 7.33 (d, J = 7.8 Hz, 2H), 7.19 (d, J = 7.8 Hz, 2H), 2.26 (d, J = 7.4 Hz, 12H). The 2h is a known compound 5,11. 4,4'-sulfinylbis(1,3-dimethylbenzene) (2i): Procedure: Following a similar procedure for the synthesis of 2b, the title compound 2i was obtained as a white solid, 1.81 g, 85% yield. (Rf = 0.27, eluent: PE/EtOAc = 4/1) 10

11 1 H NMR (600 MHz, CDCl 3 ): δ 7.56 (d, J = 8.0 Hz, 2H), 7.14 (d, J = 8.0 Hz, 2H), 7.00 (s, 2H), 2.34 (d, J = 15.6 Hz, 12H). 13 C NMR (151 MHz, CDCl 3 ): δ 141.3, 138.8, 136.4, 131.5, 127.8, 126.0, 21.2, The 2i is a known compound 6,12. 2,2'-sulfinylbis(1,4-dimethylbenzene) (2j): Procedure: Following a similar procedure for the synthesis of 2b, the title compound 2j was obtained as a white solid, 1.61 g, 76% yield. (Rf = 0.38, eluent: PE/EtOAc = 4/1) 1 H NMR (600 MHz, CDCl 3 ): δ 7.49 (s, 2H), 7.16 (d, J = 7.7 Hz, 2H), 7.07 (d, J = 7.7 Hz, 2H), 2.35 (d, J = 12.4 Hz, 12H). The 2j is a known compound 5,13. 2,2'-sulfinylbis(1,3,5-trimethylbenzene) (2k): Procedure: Following a similar procedure for the synthesis of 2b, the title compound 2k was obtained as a white solid, 2.09 g, 89% yield. (Rf = 0.4, eluent: PE/EtOAc = 4/1) 1 H NMR (600 MHz, CDCl 3 ): δ 6.81 (s, 4H), 2.40 (s, 12H), 2.26 (s, 6H). The 2k is a known compound 5,14. 11

12 2-(phenylsulfinyl)naphthalene (2l): Step a: To a solution of 2-bromonaphthalene (1.04 g, 5.0 mmol) in THF (28 ml) was added n-buli (2.5 M in pentane, 2.1 ml, 5.25 mmol) at -78 ºC. The mixture was stirred for 30 min. Then to the mixture was added a solution of (PhS) 2 (1.20 g, 5.5 mmol) in THF (10 ml) dropwise under the same temperature. After stirring under the same temperature for 30 min, the mixture was warmed to 0 ºC and stirred for 1 h, then warmed to room temperature and stirred for 2.5 h. After that, the solvent was evaporated and the crude residue was dissolved in DCM (20 ml) and washed with brine (20 ml). The aqueous layer was washed with DCM (20 ml) and the combined organic layers were dried over Na 2 SO 4, filitrated and concentrated in vacuo. The obtained residue was purified by flash column chromatography on silica gel to afford naphthalen-2-yl(phenyl)sulfane as a white solid, 1.07 g, 91% yield. Step b: Following a similar procedure for the synthesis of 2e, the title compound 2l was obtained as a white solid, 1.02 mg, 89% yield. (Rf = 0.26, eluent: PE/EtOAc = 5/1) 1 H NMR (600 MHz, CDCl 3 ): δ 8.32 (s, 1H), (m, 1H), (m, 2H), (m, 2H), (m, 2H), (m, 1H), (m, 3H). The 1 H NMR of 2l is consistent with the reported spectra 15. Bis(1-naphthyl) Sulfoxide (2m): Procedure:To a precooled solution of 1-bromonaphthalene (3.4 ml, 24.2 mmol) in THF (70 ml) was added n-buli (8.8 ml, 22 mmol, 2.5 M solution in THF) dropwise at -78 C. After 30 min, a solution of SOCl 2 (0.9 ml, 12.8 mmol) in THF (23 ml) was added to the mixture within 40 min. 12

13 After stirring at -78 C for another 30 min, the mixture was gradually warmed to room temperature and stirred for 60 min. Then, the mixture was diluted with Et 2 O (40 ml), poured onto ice water (40 ml) with care, and neutralized with NaHCO 3 (sat. aqueous solution). The aqueous layer was extracted with Et 2 O (3 40 ml). The combined organic layers were dried over Na 2 SO 4 and concentrated under reduced pressure. The obtained residue was purified by flash column chromatography on silica gel to afford the title compound 2m as a white solid, mg, 23% yield. (Rf = 0.38, eluent: PE/EtOAc = 3/1) 1 H NMR (600 MHz, CDCl 3 ): δ (m, 2H), 8.04 (dd, J = 7.3, 1.1 Hz, 2H), 7.96 (d, J = 8.2 Hz, 2H), (m, 2H), (m, 2H), (m, 4H). The 1 H NMR of 2m is consistent with the reported spectra 16. dibenzo[b,d]thiophene 5-oxide (2n): Procedure:Following a similar procedure for the synthesis of 2e, the title compound 2n was obtained as a white solid, 1.06 g, 66% yield. (Rf = 0.34, eluent: PE/EtOAc = 1/1) 1 H NMR (600 MHz, CDCl 3 ): δ 7.99 (d, J = 7.6 Hz, 2H), 7.81 (d, J = 7.7 Hz, 2H), (m, 2H), (m, 2H). 13 C NMR (151 MHz, CDCl 3 ): δ 145.1, 137.1, 132.5, 129.5, 127.5, The 1 H NMR and 13 C NMR of 2n are consistent with the reported spectra (phenylsulfinyl)thiophene (2o) Step a: To a solution of 2-bromothiophene (490 µl, 5.0 mmol) in ether (6 ml) was added t-buli (1.3 M in pentane, 7.7 ml, 10 mmol) at -78 ºC. The mixture was stirred for 30 min. Then to the 13

14 mixture was added a solution of (PhS) 2 (1.09 g, 5 mmol) in ether (6 ml) dropwise under the same temperature. And then, the mixture was warmed to 0 ºC and stirred for 1 h, then warmed to room temperature and stirred for 2.5 h. After that, H 2 O (8 ml) was added dropwise to the mixture. The aqueous layer was extracted with a 1:1 mixture (3 10 ml) of Et 2 O and petroleum ether. The combined organic layer was washed with NaOH (2 M aqueous solution) and brine, dried over Na 2 SO 4 and concentrated under reduced pressure. The obtained residue was purified by flash column chromatography on silica gel to afford 2-(Phenylthio)thiophene as a colorless oil, 960 mg, 100% yield. Step b: Following a similar procedure for the synthesis of 2e, the title compound 2o was obtained as a colorless oil, 917 mg, 88% yield. (Rf = 0.23, eluent: PE/EtOAc = 4/1) 1 H NMR (400 MHz, CDCl 3 ): δ (m, 2H), (m, 2H), (m, 3H), (m, 1H). 13 C NMR (101 MHz, CDCl 3 ): δ 148.0, 145.1, 132.2, 131.2, 131.0, 129.1, 127.1, The 1 H NMR and 13 C NMR of 2o are consistent with the reported spectra (phenylsulfinyl)thiophene (2p): Step a: To a solution of 3-Iodothiophene (508 µl, 5.0 mmol) in ether (6 ml) was added t-buli (1.3 M in pentane, 7.7 ml, 10 mmol) at -78 ºC. After stirring for 30 min, a solution of (PhS) 2 (1.09 g, 5 mmol) in ether (6 ml) was added dropwise under the same temperature. The mixture was warmed to 0 ºC and stirred for 1 h, then warmed to room temperature and stirred for 2.5 h. After that, H 2 O (8 ml) was added to the mixture. The aqueous layer was extracted with a 1:1 mixture of Et 2 O (3 10 ml) and petroleum ether. The combined organic layer was washed with NaOH (2 M aqueous solution) and brine, dried over Na 2 SO 4 and concentrated under reduced pressure. The obtained residue was purified by flash column chromatography on silica gel to afford 3-(Phenylthio)thiophene as a colorless oil, mg, 71% yield. Step b: Following a similar procedure for the synthesis of 2e, the title compound 2p was obtained 14

15 as a colorless oil, mg, 68% yield. (Rf = 0.31, eluent: PE/EtOAc = 3/1) 1 H NMR (600 MHz, CDCl 3 ): δ (m, 1H), (m, 2H), (m, 3H), 7.36 (dd, J = 5.2, 3.0 Hz, 1H), 7.05 (dd, J = 5.2, 1.3 Hz, 1H). The 1 H NMR of 2p is consistent with the reported spectra Optimization of reaction conditions General procedure A: To a flame-dried reaction tube (25 ml) was added F source (2.0 equiv) under nitrogen atmosphere. (Note: CsF was operated in glove box). Then the solvent (3 ml), diphenyl sulfoxide 2a (0.3 mmol, 61 mg) and benzyne precursor 1a (0.3 mmol, 89.5 mg) were sequentially added to the reaction tube. The mixture was stirred under the indicated temperature for 6 or 16 h. After that, to the mixture was added mesitylene (0.15 mmol, 21μL). The mixture was then stirred vigorously for a few seconds. One drop of the mixture was transferred to nmr tube to determine the NMR yields of 3aa. 15

16 4 Reactions of aryne precursor 1a with various aryl sulfoxides General procedure B:To a flame-dried reaction tube (25 ml) was added CsF (91.1 mg, 2.0 equiv) in glove box. Then MeCN (3 ml), diaryl sulfoxide 2 (0.3 mmol, 1.0 equiv) and aryne precursor 1 (0.3 mmol, 1.0 equiv) were sequentially added to the reaction tube. The mixture was stirred at 25 for 16 h. After that, the mixture was filtrated through a short plug of silica gel, concentrated and purified by flash column chromatography on silica gel to afford corresponding triaryl sulfonium salts 3. (2-phenoxyphenyl)diphenyl sulfonium trifluoromethanesulfonate (3aa): Following the general procedure B, the title compound was obtained as a white solid, m.p , 59.0 mg, 78% yield. (Rf = 0.28, eluent: DCM/MeOH = 15/1). 1 H NMR (600 MHz, CDCl 3 ): δ (m, 10H), (m, 1H), (m, 3H), (m, 2H), (m, 1H), (m, 2H). 13 C NMR (151 MHz, CDCl 3 ): δ 156.8, 153.3, 136.6, 134.9, 131.8, 131.1, 130.4, 126.2, 125.1, 122.8, (q, J = Hz, - OTf), 120.1, 117.4, One aromatic carbon peak is overlapped. 19 F NMR (565 MHz, CDCl 3 ): δ (s). IR (neat): 3056, 1578, 1468, 1445, 1263, 1139, 1029, 873, 744, 681, 634. HRMS: calculated for C 24 H 19 OS + ([M-OTf - ] + ): ; found: MS (ESI) m/z ( - OTf) calcd for CF 3 O 3 S: , found: aa 16

17 Single crystals of product 3aa was obtained through slow evaporation at room temperature of a solution in ethyl acetate dichloromethane. Bond precision: C-C = A Wavelength= Cell: a=9.6162(5) b= (9) c= (6) alpha=90 beta=96.703(3) gamma=90 Temperature: 296 K Calculated Reported Volume (2) (2) Space group P 21/n P2(1)/n Hall group -P 2yn? Moiety formula C24 H19 O S, C F3 O3 S? Sum formula C25 H19 F3 O4 S2 C25 H19 F3 O4 S2 Mr Dx,g cm Z 4 4 Mu (mm-1) F F000' h,k,lmax 11,23,14 11,23,14 Nref Tmin,Tmax 0.930, ,0.950 Tmin' Correction method= # Reported T Limits: Tmin=0.930 Tmax=0.950 AbsCorr = NONE Data completeness= Theta(max)= R(reflections)= ( 2697) wr2(reflections)= ( 4110) S = Npar= 307 For more details please see the CIF file attached with ESI. The crystal data of 3aa has already been deposited at Cambridge Crystallographic Data Center, UK, and the CCDC reference number is

18 bis(4-methoxyphenyl)(2-phenoxyphenyl) sulfonium trifluoro methanesulfonate (3ab): Following the general procedure B, the title compound was obtained as a yellowish oil, 81.0 mg, 96% yield. (Rf = 0.27, eluent: DCM/MeOH = 15/1). 1 H NMR (600 MHz, CDCl 3 ): δ 7.64 (d, J = 8.6 Hz, 4H), 7.58 (t, J = 7.6 Hz, 1H), (m, 3H), (m, 5H), (m, 1H), 6.89 (d, J = 8.2 Hz, 1H), 6.83 (d, J = 7.7 Hz, 2H), 3.87 (s, 6H). 13 C NMR (151 MHz, CDCl 3 ): δ 164.5, 156.1, 153.5, 135.9, 132.9, 130.3, 130.3, 125.9, 124.8, (q, J = Hz, - OTf), 119.9, 117.4, 117.2, 114.8, 112.4, IR (neat): 3093, 2947, 2845, 1574, 1465, 1417, 1255, 1147, 1074, 1028, 832, 798, 753, 694, 635. HRMS: calculated for C 26 H 23 O 3 S + ([M-OTf - ] + ): ; found: (2-phenoxyphenyl)di-p-tolyl sulfonium trifluoromethanesulfonate (3ac): Following the general procedure B, the title compound was obtained as a white solid, m.p , 77.0 mg, 96% yield. (Rf = 0.31, eluent: DCM/MeOH = 15/1). 1 H NMR (600 MHz, CDCl 3 ): δ (m, 5H), (m, 4H), (m, 3H), (m, 1H), (m, 1H), 6.90 (d, J = 8.3 Hz, 1H), 6.84 (d, J = 7.7 Hz, 2H), 2.44 (s, 6H). 13 C NMR (151 MHz, CDCl 3 ): δ 156.5, 153.3, 146.3, 136.2, 132.3, 130.8, 130.7, 130.3, 126.0, 124.9, (q, J = Hz, - OTf), 119.9, 119.2, 117.3, 113.5, IR (neat): 3060, 2921, 1578, 1466, 1403, 1257, 1148, 1028, 872, 752, 695. HRMS: calculated for C 26 H 23 OS + ([M-OTf - ] + ): ; found: di([1,1'-biphenyl]-4-yl)(2-phenoxyphenyl) sulfonium trifluoro methane sulfonate (3ad): Following the general procedure B, the title compound was obtained as a yellowish oil, 38.0 mg, 39% yield. (Rf = 0.30, eluent: DCM/MeOH = 15/1). 18

19 51% of 4,4''-sulfinyldi-1,1'-biphenyl was recovered (54.2 mg, Rf = 0.35, eluent: PE/EtOAc = 5/1). 1 H NMR (600 MHz, CDCl 3 ): δ (m, 8H), (m, 5H), (m, 4H), (m, 2H), (m, 4H), (m, 1H), 6.96 (d, J = 8.4 Hz, 1H), 6.90 (d, J = 7.8 Hz, 2H). 13 C NMR (151 MHz, CDCl 3 ): δ 156.7, 153.5, 147.7, 137.9, 136.4, 131.7, 131.3, 130.4, 130.1, 129.2, 129.2, 127.4, 126.1, 125.2, 121.1, (q, J = Hz, - OTf), 120.0, 117.6, IR (neat): 3062, 2923, 1578, 1466, 1258, 1148, 1028, 753, 694. HRMS: calculated for C 36 H 27 OS + ([M-OTf - ] + ): ; found: (4-chlorophenyl)(2-phenoxyphenyl)(p-tolyl) sulfonium trifluoro methanesulfonate (3ae): Following the general procedure B, the title compound was obtained as a yellowish oil, 48.9 mg, 59% yield. (Rf = 0.32, eluent: DCM/MeOH = 15/1) 1 H NMR (600 MHz, CDCl 3 ): δ (m, 2H), (m, 4H), (m, 1H), (m, 2H), (m, 3H), (m, 2H), 6.92 (d, J = 8.4 Hz, 1H), (m, 2H), 2.46 (s, 3H). 13 C NMR (151 MHz, CDCl 3 ): δ 156.5, 153.3, 146.6, 141.5, 136.4, 132.4, 132.3, 131.8, 131.1, 130.9, 130.3, 126.0, 125.1, 121.7, (q, J = Hz, - OTf), 119.9, 118.6, 117.4, 113.0, IR (neat): 3062, 2924, 2851, 1577, 1466, 1396, 1256, 1148, 1091, 1028, 745, 695, 630. HRMS: calculated for C 25 H 20 OClS + ([M-OTf - ] + ): ; found: bis(4-chlorophenyl)(2-phenoxyphenyl) sulfonium trifluoromethane sulfonate (3af): Following the general procedure B, the title compound was obtained as a yellow oil, 11.1 mg, 13% yield. (Rf = 0.25, eluent: DCM/MeOH = 15/1). 57% of 4,4'-sulfinylbis(chlorobenzene) was recovered (46.4 mg, Rf = 0.35, eluent: PE/EtOAc = 5/1). 1 H NMR (600 MHz, CDCl 3 ): δ (m, 4H), (m, 4H), (m, 1H), (m, 3H), 7.23 (dd, J = 8.2, 1.3 Hz, 1H), (m, 1H), 6.91 (d, J = 8.3 Hz, 1H), 6.85 (d, J = 7.8 Hz, 2H). 19

20 13 C NMR (151 MHz, CDCl 3 ): δ 156.5, 153.2, 141.8, 136.6, 132.7, 131.9, 131.0, 130.3, 126.1, 125.1, 121.0, (q, J = Hz, - OTf),119.9, 117.4, IR (neat): 3088, 1577, 1467, 1424, 1256, 1155, 1091, 1028, 796, 746, 636. HRMS: calculated for C 24 H 17 Cl 2 OS + ([M-OTf - ] + ): ; found: bis(3,4-dimethylphenyl)(2-phenoxyphenyl) sulfonium trifluoro methanesulfonate (3ah): Following the general procedure B, the title compound was obtained as a yellow oil, 81.0 mg, 96% yield. (Rf = 0.28, eluent: DCM/MeOH = 15/1). 1 H NMR (600 MHz, CDCl 3 ): δ (m, 1H), 7.46 (d, J = 8.1 Hz, 2H), 7.41 (s, 2H), (m, 5H), (m, 1H), (m, 1H), (m, 1H), (m, 2H), 2.33 (d, J = 19.4 Hz, 12H). 13 C NMR (151 MHz, CDCl 3 ): δ 156.4, 153.5, 145.0, 141.0, 136.2, 132.6, 131.2, 130.8, 130.2, 128.1, 125.8, 125.1, (q, J = Hz, - OTf),119.8, 119.1, 117.4, 113.6, 19.9, IR (neat): 3065, 2922, 1577, 1466, 1388, 1258, 1143, 1085, 1028, 818, 799, 753, 696, 634. HRMS: calculated for C 28 H 27 OS + ([M-OTf - ] + ): ; found: bis(2,4-dimethylphenyl)(2-phenoxyphenyl) sulfonium trifluoro methanesulfonate (3ai): Following the general procedure B, the title compound was obtained as a yellow oil, 79.0 mg, 94% yield. (Rf = 0.29, eluent: DCM/MeOH = 15/1). 1 H NMR (600 MHz, CDCl 3 ): δ (m, 1H), (m, 7H), (m, 1H), (m, 3H), 6.97 (d, J = 7.9 Hz, 1H), 6.83 (d, J = 7.8 Hz, 2H), 2.45 (d, J = 29.1 Hz, 12H). 13 C NMR (151 MHz, CDCl 3 ): δ 156.7, 153.5, 146.4, 140.1, 136.6, 133.9, 130.7, 130.4, 130.3, 130.2, 126.0, 125.6, (q, J = Hz, - OTf),119.6, 118.0, 116.7, 111.2, 21.3, IR (neat): 3065, 2923, 1577, 1466, 1385, 1260, 1144, 1028, 872, 801, 752, 695, 634. HRMS: calculated for C 28 H 27 OS + ([M-OTf - ] + ): ; found

21 bis(2,5-dimethylphenyl)(2-phenoxyphenyl) sulfonium trifluoro methanesulfonate (3aj): Following the general procedure B, the title compound was obtained as a yellowish solid, m.p , 68.9 mg, 82% yield. (Rf = 0.31, eluent: DCM/MeOH = 15/1). 1 H NMR (600 MHz, CDCl 3 ): δ (m, 1H), (m, 2H), (m, 3H), (m, 2H), (m, 1H), (m, 1H), 7.02 (d, J = 8.4 Hz, 1H), 6.90 (s, 2H), 6.83 (d, J = 8.4 Hz, 2H), 2.47 (s, 6H), 2.36 (s, 6H). 13 C NMR (151 MHz, CDCl 3 ): δ 156.7, 153.6, 140.1, 137.4, 136.9, 135.9, 133.2, 131.3, 130.4, 129.9, 126.0, 126.0, (q, J = Hz, - OTf),119.8, 119.5, 118.2, 110.5, 21.1, IR (neat): 3060, 2923, 1577, 1465, 1386, 1259, 1144, 1028, 871, 797, 752, 694, 634. HRMS: calculated for C 28 H 27 OS + ([M-OTf - ] + ): ; found: dimesityl(2-phenoxyphenyl) sulfonium trifluoromethanesulfonate (3ak): Following the general procedure B, the title compound was obtained as a yellowish oil, 85.4 mg, 97% yield. (Rf = 0.29, eluent: DCM/MeOH = 15/1). 1 H NMR (600 MHz, CDCl 3 ): δ (m, 1H), (m, 2H), (m, 1H), (m, 1H), (m, 5H), 7.00 (d, J = 8.4 Hz, 1H), 6.91 (d, J = 8.0 Hz, 2H), 2.35 (s, 6H), 2.21 (s, 12H). Carbon of triflate anion cannot be found. 13 C NMR (151 MHz, CDCl 3 ): δ 157.2, 153.3, 145.7, 141.1, 136.5, 133.3, 130.5, 130.3, 126.1, 125.9, 119.7, 117.6, 116.2, 111.9, 21.0, IR (neat): 3062, 2921, 1576, 1466, 1381, 1259, 1147, 1029, 871, 752, 695, 635. HRMS: calculated for C 30 H 31 OS + ([M-OTf - ] + ): ; found: naphthalen-1-yl(2-phenoxyphenyl)(phenyl) sulfonium trifluoromethane sulfonate (3al): Following the general procedure B, the title compound was obtained as a yellowish oil, 51.7 mg, 62% yield. (Rf = 0.23, eluent: DCM/MeOH = 20/1). 21

22 1 H NMR (600 MHz, CDCl 3 ): δ 8.51 (d, J = 1.5 Hz, 1H), 8.18 (d, J = 8.8 Hz, 1H), 8.04 (d, J = 8.2 Hz, 1H), 7.96 (d, J = 8.2 Hz, 1H), (m, 6H), (m, 3H), (m, 3H), (m, 1H), 7.16 (t, J = 7.4 Hz, 1H), 6.94 (d, J = 8.3 Hz, 1H), 6.85 (d, J = 7.8 Hz, 2H). 13 C NMR (151 MHz, CDCl 3 ): δ 156.8, 153.3, 136.5, 135.2, 134.7, 134.3, 133.1, 132.3, 131.7, 131.1, 130.9, 130.5, 130.3, 129.3, 128.7, 128.2, 126.1, 125.0, 123.9, 123.4, (q, J = Hz, - OTf), 120.1, 118.8, 117.4, IR (neat): 3061, 3012, 2926, 2584, 1578, 1466, 1257, 1148, 1028, 745, 685, 634. HRMS: calculated for C 28 H 21 OS + ([M-OTf - ] + ): ; found: di(naphthalen-1-yl)(2-phenoxyphenyl) sulfonium trifluoro methanesulfonate (3am): Following the general procedure B, the title compound was obtained as a yellowish oil, 34.1 mg, 38% yield. (Rf = 0.25, eluent: DCM/MeOH = 15/1). 1 H NMR (600 MHz, CDCl 3 ): δ 8.32 (d, J = 8.2 Hz, 2H), 8.17 (d, J = 8.3 Hz, 2H), 8.10 (d, J = 7.8 Hz, 2H), (m, 9H), (m, 3H), (m, 2H), 7.05 (d, J = 7.9 Hz, 1H), 6.89 (d, J = 7.7 Hz, 2H). 13 C NMR (151 MHz, CDCl 3 ): δ 157.1, 153.8, 137.1, 136.0, 134.4, 132.2, 131.9, 130.4, 130.4, 130.1, 129.9, 128.5, 126.9, 126.0, 125.9, 121.4, (q, J = Hz, - OTf), 119.7, 118.2, 116.9, IR (neat): 3062, 3011, 2923, 1592, 1577, 1504, 1466, 1258, 1028, 797, 749, 694, 635. HRMS: calculated for C 32 H 23 OS + ([M-OTf - ] + ): ; found: (2-phenoxyphenyl)-5H-dibenzo[b,d]thiophen-5-ium trifluoro methanesulfonate (3an): Following the general procedure B, was obtained as a white solid, m.p , 53.6 mg, 71% yield. (Rf = 0.26, eluent: DCM/MeOH = 15/1). 1 H NMR (600 MHz, CDCl 3 ): δ 8.22 (d, J = 8.0 Hz, 2H), 8.11 (d, J = 7.7 Hz, 2H), (m, 2H), (m, 3H), m, 1H), (m, 2H), (m, 2H), 6.79 (d, J = 8.4 Hz, 1H), 6.76 (d, J = 8.0 Hz, 2H). 13 C NMR (151 MHz, CDCl 3 ): δ 157.5, 153.4, 139.5, 136.9, 134.1, 132.5, 131.4, 130.2, 129.2, 22

23 128.2, 125.8, 124.8, 124.0, (q, J = Hz, - OTf), 119.5, 118.2, IR (neat): 3063, 1577, 1472, 1255, 1147, 1072, 1025, 794, 755, 693, 631. HRMS: calculated for C 24 H 17 OS + ([M-OTf - ] + ): ; found: phenyl-10H-phenoxathiin-10-ium trifluoromethanesulfonate (4): Following the general procedure B, the title compound was obtained as a white solid, m.p , (33.3 mg, 52% yield, from the reaction of 1a and 2n), (39.7 mg, 62% yield, from the reaction of 1a and 2o) (Rf = 0.26, eluent: DCM/MeOH = 15/1). 1 H NMR (600 MHz, CDCl 3 ): δ (m, 2H), (m, 2H), (m, 2H), (m, 3H), (m, 4H). 13 C NMR (151 MHz, CDCl 3 ): δ 151.6, 136.8, 134.4, 132.0, 131.5, 131.2, 129.0, 127.6, (q, J = Hz, - OTf), 120.3, F NMR (565 MHz, CDCl 3 ): δ (s). IR (neat): 3084, 1581, 1459, 1443, 1258, 1122, 1150, 1028, 871, 753, 683, 634. HRMS: calculated for C 18 H 13 OS + ([M-OTf - ] + ): ; found: Single crystals of product 4 was obtained through slow evaporation at room temperature of a solution in ethyl acetate dichloromethane. 4 Bond precision: C-C = A Wavelength= Cell: a=9.2490(2) b= (3) c= (4) alpha=90 beta=95.804(2) gamma=90 23

24 Temperature: 296 K Calculated Reported Volume (8) (8) Space group P 21/n P2(1)/n Hall group -P 2yn? Moiety formula C18 H13 O S, C F3 O3 S? Sum formula C19 H13 F3 O4 S2 C19 H13 F3 O4 S2 Mr Dx,g cm Z 4 4 Mu (mm-1) F F000' h,k,lmax 11,13,24 11,13,24 Nref Tmin,Tmax 0.923, ,0.967 Tmin' Correction method= # Reported T Limits: Tmin=0.923 Tmax=0.967 AbsCorr = NONE Data completeness= Theta(max)= R(reflections)= ( 3075) wr2(reflections)= ( 4322) S = Npar= 253 For more details please see the CIF file attached with ESI. The crystal data of 4 has already been deposited at Cambridge Crystallographic Data Center, UK, and the CCDC reference number is Reactions of aryne precursors with aryl sulfoxides (2-methoxy-6-(3-methoxyphenoxy)phenyl)diphenyl sulfonium trifluoro methanesulfonate (3ba): Following the general procedure B, the title compound was obtained as a yellow oil, 63.0 mg, 74% yield. (Rf = 0.28, eluent: DCM/MeOH = 15/1). 1 H NMR (600 MHz, CDCl 3 ): δ (m, 11H), 7.19 (t, J = 8.2 Hz, 1H), 6.98 (d, J = 8.6, 1H), (m, 1H), (m, 1H), (m, 1H), (m, 1H), 3.90 (s, 3H), 3.71 (s, 3H). 13 C NMR (151 MHz, CDCl 3 ): δ 161.1, 161.1, 159.2, 154.3, 139.3, 133.9, 131.1, 130.7, 130.0, 123.4, 111.6, 111.5, (q, J = Hz, - OTf), 110.6, 108.0, 105.7, 57.3, One aromatic 24

25 carbon peak is overlapped. 19 F NMR (565 MHz, CDCl 3 ): δ (s). IR (neat): 3088, 2944, 2839, 1573, 1473, 1442, 1250, 1137, 1075, 1028, 747, 682, 636. HRMS: calculated for C 26 H 23 O 3 S + ([M-OTf - ] + ): ; found: (2-methoxy-6-(3-methoxyphenoxy)phenyl)di-p-tolyl sulfonium tri fluoromethanesulfonate (3bc): Following the general procedure B, the title compound was obtained as a yellow oil, 72.1 mg, 81% yield. (Rf = 0.29, eluent: DCM/MeOH = 15/1). 1 H NMR (600 MHz, CDCl 3 ): δ 7.65 (t, J = 8.5 Hz, 1H), 7.49 (d, J = 8.5 Hz, 4H), 7.41 (d, J = 8.4 Hz, 4H), (m, 1H), 6.96 (d, J = 8.2 Hz, 1H), (m, 1H), (m, 1H), 6.32 (dd, J = 7.9, 2.0 Hz, 1H), (m, 1H), 3.89 (s, 3H), 3.71 (s, 3H), 2.40 (s, 6H). 13 C NMR (101 MHz, CDCl 3 ): δ 160.9, 160.9, 158.9, 154.5, 145.2, 138.9, 131.6, 130.6, 129.8, 119.9, 111.3, 111.3, 110.8, 108.0, 105.5, 99.7, 57.2, 55.4, Carbon of triflate anion cannot be found. IR (neat): 3091, 2946, 2839, 1585, 1473, 1440, 1403, 1249, 1137, 1074, 1028, 777, 754, 697, 636. HRMS: calculated for C 28 H 27 O 3 S + ([M-OTf - ] + ): ; found: (4-chlorophenyl)(2-methoxy-6-(3-methoxyphenoxy)phenyl)(p-tolyl) sulfonium trifluoromethanesulfonate (3be): Following the general procedure B, the title compound was obtained as a yellow oil, 59.2 mg, 64% yield. (Rf = 0.20, eluent: DCM/MeOH = 15/1) 1 H NMR (400 MHz, CDCl 3 ): δ 7.67 (t, J = 8.5 Hz, 1H), (m, 6H), 7.47 (d, J = 8.4 Hz, 2H), 7.21 (t, J = 8.2 Hz, 1H), 6.97 (d, J = 8.5 Hz, 1H), 6.73 (dd, J = 8.1, 2.1 Hz, 1H), 6.56 (d, J = 8.5 Hz, 1H), 6.34 (dd, J = 8.3, 1.9 Hz, 1H), 6.28 (t, J = 2.3 Hz, 1H), 3.93 (s, 3H), 3.74 (s, 3H), 2.45 (s, 3H). 13 C NMR (101 MHz, CDCl 3 ): δ 161.1, 161.1, 159.0, 154.5, 146.0, 140.4, 139.2, 132.0, 131.2, 131.1, 130.7, 130.4, 122.7, 119.2, 111.6, 111.4, 110.9, 108.2, 105.6, 99.2, 57.4, 55.6, Carbon 25

26 of triflate anion cannot be found. IR (neat): 3087, 2945, 1585, 1473, 1439, 1395, 1249, 1137, 1075, 1028, 807, 777, 744, 696, 636. HRMS: calculated for C 27 H 24 O 3 ClS + ([M-OTf - ] + ): ; found: bis(3,4-dimethylphenyl)(2-methoxy-6-(3-methoxyphenoxy)phenyl) sulfonium trifluoromethanesulfonate (3bh): Following the general procedure B, the title compound was obtained as a yellow oil, 63.4 mg, 68% yield. (Rf = 0.25, eluent: DCM/MeOH = 15/1). 1 H NMR (400 MHz, CDCl 3 ): δ (m, 1H), (m, 6H), (m, 1H), 7.01 (d, J = 8.5 Hz, 1H), (m, 1H), 6.58 (d, J = 8.4 Hz, 1H), 6.28 (dd, J = 8.1, 2.2 Hz, 1H), (m, 1H), 3.93 (s, 3H), 3.71 (s, 3H), 2.28 (d, J = 17.6 Hz, 12H). 13 C NMR (101 MHz, CDCl 3 ): δ 161.0, 158.5, 154.8, 143.9, 140.2, 138.8, 132.0, 130.5, 130.3, 127.4, 120.0, 111.3, 111.0, 110.9, 108.3, 105.3, 100.4, 57.3, 55.4, 19.8, 19.8.One carbon of benzene ring and carbon of triflate anion cannot be found. IR (neat): 3086, 2946, 1585, 1472, 1440, 1388, 1250, 1138, 1077, 1029, 777, 744, 729, 699, 636. HRMS: calculated for C 30 H 31 O 3 S + ([M-OTf - ] + ): ; found: dimesityl(2-methoxy-6-(3-methoxyphenoxy)phenyl) sulfonium tri fluoromethanesulfonate (3bk): Following the general procedure B, the title compound was obtained as a yellow oil, 72.9 mg, 75% yield. (Rf = 0.29, eluent: DCM/MeOH = 15/1). 1 H NMR (400 MHz, CDCl 3 ): δ 7.66 (t, J = 8.5 Hz, 1H), 7.15 (t, J = 8.3 Hz, 1H), 7.01 (d, J = 8.7 Hz, 5H), 6.67 (dd, J = 8.4, 2.4 Hz, 1H), 6.56 (d, J = 8.5 Hz, 1H), 6.19 (dd, J = 8.0, 2.0 Hz, 1H), 6.08 (t, J = 2.3 Hz, 1H), 3.90 (s, 3H), 3.70 (s, 3H), 2.28 (s, 6H), 2.22 (s, 12H). 13 C NMR (151 MHz, CDCl 3 ): δ 160.9, 160.4, 158.2, 154.3, 144.6, 140.7, 137.9, 132.6, 130.5, (q, J = Hz, - OTf), 119.0, 111.3, 110.9, 110.8, 107.8, 105.2, 100.8, 57.6, 55.4, 20.9, IR (neat): 3088, 2923, 2844, 1585, 1472, 1440, 1382, 1250, 1137, 1075, 1029, 753, 701,

27 HRMS: calculated for C 32 H 35 O 3 S + ([M-OTf - ] + ): ; found: (6-(benzo[d][1,3]dioxol-5-yloxy)benzo[d][1,3]dioxol-5-yl)diphenyl sulfonium trifluoromethanesulfonate (3ca): Following the general procedure B, the title compound was obtained as a yellow oil, 40.2 mg, 45% yield. (Rf = 0.20, eluent: DCM/MeOH = 5/1). 1 H NMR (600 MHz, CDCl 3 ): δ (m, 10H), 6.71 (d, J = 8.4 Hz, 1H), 6.48 (d, J = 9.9 Hz, 2H), 6.38 (d, J = 2.4 Hz, 1H), 6.34 (dd, J = 8.4, 2.5 Hz, 1H), 6.10 (s, 2H), 5.97 (s, 2H). 13 C NMR (151 MHz, CDCl 3 ): δ 155.1, 154.7, 148.8, 148.4, 145.6, 145.4, 134.7, 131.7, 130.8, 123.8, (q, J = Hz, - OTf), 112.6, 108.6, 108.4, 103.8, 102.1, 102.0, 101.7, IR (neat): 3058, 2922, 1587, 1491, 1411, 1253, 1159, 1028, 832, 789, 636. HRMS: calculated for C 26 H 19 O 5 S + ([M-OTf - ] + ): ; found: (6-(benzo[d][1,3]dioxol-5-yloxy)benzo[d][1,3]dioxol-5-yl)di-p-tolyl sulfonium trifluoromethanesulfonate (3cc): Following the general procedure B, the title compound was obtained as a brown oil, 66.5 mg, 71% yield. (Rf = 0.28, eluent: DCM/MeOH = 15/1). 1 H NMR (600 MHz, CDCl 3 ): δ (m, 8H), 6.69 (d, J = 8.3 Hz, 1H), 6.43 (s, 1H), 6.40 (s, 1H), (m, 2H), 6.07 (s, 2H), 5.94 (s, 2H), 2.45 (s, 6H). 13 C NMR (151 MHz, CDCl 3 ): δ 154.7, 154.3, 148.6, 148.4, 146.1, 145.4, 145.2, 132.3, 130.4, (q, J = Hz, - OTf), 120.2, 112.4, 108.5, 107.9, 103.7, 102.0, 101.9, 99.5, One aromatic carbon peak is overlapped. IR (neat): 3058, 2919, 1611, 1469, 1422, 1375, 1254, 1177, 1150, 1090, 1026, 923, 810, 751, 666, 635. HRMS: calculated for C 28 H 23 O 5 S + ([M-OTf - ] + ): ; found:

28 (6-(benzo[d][1,3]dioxol-5-yloxy)benzo[d][1,3]dioxol-5-yl)bis(3,4-dim ethylphenyl) sulfonium trifluoromethanesulfonate (3ch): Following the general procedure B, the title compound was obtained as a yellow oil, 68.1 mg, 70% yield. (Rf = 0.25, eluent: DCM/MeOH = 15/1). 1 H NMR (600 MHz, CDCl 3 ): δ 7.46 (d, J = 8.2 Hz, 2H), 7.38 (d, J = 2.0 Hz, 2H), 7.31 (dd, J = 8.2, 2.2 Hz, 2H), 6.71 (d, J = 8.1 Hz, 1H), 6.46 (s, 1H), 6.41 (s, 1H), (m, 2H), 6.10 (s, 2H), 5.95 (s, 2H), 2.36 (s, 6H), 2.33 (s, 6H). 13 C NMR (151 MHz, CDCl 3 ): δ 154.6, 154.1, 148.6, 148.5, 145.3, 145.2, 144.8, 141.0, 132.6, 130.8, 127.7, (q, J= Hz, - OTf), 120.1, 112.3, 108.4, 107.9, 103.7, 102.7, 101.9, 99.6, 19.9, One aromatic carbon peak is overlapped. IR (neat): 3059, 2920, 1610, 1470, 1422, 1393, 1254, 1177, 1148, 1027, 923, 814, 753, 701, 635. HRMS: calculated for C 30 H 27 O 5 S + ([M-OTf - ] + ): ; found: (6-(benzo[d][1,3]dioxol-5-yloxy)benzo[d][1,3]dioxol-5-yl)bis(2,4-dim ethylphenyl) sulfonium trifluoromethanesulfonate (3ci): Following the general procedure B, the title compound was obtained as a brown oil, 65.0 mg, 67% yield. (Rf = 0.25, eluent: DCM/MeOH = 15/1). 1 H NMR (600 MHz, CDCl 3 ): δ (m, 4H), 7.07 (d, J = 8.2 Hz, 2H), 6.71 (d, J = 8.2 Hz, 1H), 6.49 (s, 1H), (m, 2H), 6.28 (s, 1H), 6.13 (s, 2H), 5.95 (s, 2H), (m, 12H). 13 C NMR (151 MHz, CDCl 3 ): δ 155.1, 154.5, 148.7, 148.6, 146.2, 145.8, 145.4, 139.7, 133.9, 130.3, 129.9, (q, J = Hz, - OTf), 117.8, 112.1, 108.5, 107.6, 103.9, 102.0, 101.7, 100.0, 21.3, One aromatic carbon peak is overlapped. IR (neat): 3050, 3009, 2917, 1609, 1469, 1380, 1260, 1177, 1142, 1027, 923, 814, 751, 667, 635. HRMS: calculated for C 30 H 27 O 5 S + ([M-OTf - ] + ): ; found

29 (6-(benzo[d][1,3]dioxol-5-yloxy)benzo[d][1,3]dioxol-5-yl)bis(2,5-dimethy lphenyl) sulfonium trifluoromethanesulfonate (3cj): Following the general procedure B, the title compound was obtained as a yellowish oil, 63.4 mg, 65% yield. (Rf = 0.25, eluent: DCM/MeOH = 15/1). 1 H NMR (600 MHz, CDCl 3 ): δ (m, 2H), (m, 2H), 6.91 (s, 2H), 6.71 (d, J = 8.2 Hz, 1H), 6.53 (s, 1H), (m, 3H), 6.16 (s, 2H), 5.95 (s, 2H), 2.43 (s, 6H), 2.37 (s, 6H). 13 C NMR (151 MHz, CDCl 3 ): δ 155.3, 154.6, 148.7, 148.6, 145.9, 145.4, 140.0, 137.0, 135.7, 133.2, 129.5, 120.8, (q, J = Hz, - OTf), 111.9, 108.5, 107.9, 104.1, 102.0, 101.6, 100.2, 21.1, One aromatic carbon peak is overlapped. IR (neat): 2919, 1610, 1471, 1422, 1396, 1259, 1178, 1143, 1027, 923, 816, 753, 696, 635. HRMS: calculated for C 30 H 27 O 5 S + ([M-OTf - ] + ): ; found: (6-(benzo[d][1,3]dioxol-5-yloxy)benzo[d][1,3]dioxol-5-yl)dimesityl sulfonium trifluoromethanesulfonate (3ck): Following the general procedure B, the title compound was obtained as a yellowish oil, 58.8 mg, 58% yield. (Rf = 0.25, eluent: DCM/MeOH = 15/1). 1 H NMR (600 MHz, CDCl 3 ): δ 7.13 (s, 4H), 6.77 (d, J = 8.3 Hz, 1H), 6.52 (s, 1H), (m, 3H), 6.14 (s, 2H), 5.99 (s, 2H), 2.37 (s, 6H), 2.24 (s, 12H). 13 C NMR (151 MHz, CDCl 3 ): δ 155.1, 154.9, 148.9, 148.3, 145.9, 145.7, 145.6, 140.8, 133.4, (q, J = Hz, - OTf), 117.3, 112.2, 108.7, 107.3, 104.1, 102.1, 101.8, 99.6, 21.1, One aromatic carbon peak is overlapped. IR (neat): 2920, 1600, 1469, 1422, 1252, 1177, 1149, 1090, 1027, 923, 853, 750, 665, 635. HRMS: calculated for C 32 H 31 O 5 S + ([M-OTf - ] + ): ; found:

30 (2-(3,4-difluorophenoxy)-4,5-difluorophenyl)diphenyl sulfonium trifluoro methanesulfonate (3da): Following the general procedure B, the title compound was obtained as a yellow oil, 33.6 mg, 39% yield. (Rf = 0.29, eluent: DCM/MeOH = 15/1). 1 H NMR (600 MHz, CDCl 3 ): δ (m, 6H), (m, 4H), (m, 1H), (m, 2H), (m, 2H). 13 C NMR (151 MHz, CDCl 3 ): δ (dd, J = Hz, 14.3 Hz), (d, J = 9.1 Hz), (dd, J = Hz, 13.6 Hz), (dd, J = Hz, 13.6 Hz), (d, J = 9.1 Hz), (dd, J = Hz, 12.8 Hz), 135.0, 131.8, 131.2, 122.2, (q, J = Hz, - OTf), (d, J = 22.7 Hz), (d, J = 18.1 Hz), (m), (d, J = 21.1 Hz), (m), (d, J = 22.7 Hz). 19 F NMR (565 MHz, CDCl 3 ): δ (s), (d, J = 22.3 Hz), (d, J = 21.8 Hz), (d, J = 22.2 Hz), (d, J = 21.7 Hz). IR (neat): 3063, 1607, 1491, 1447, 1206, 1159, 1029, 958, 832, 748, 683, 636. HRMS: calculated for C 24 H 15 OF 4 S + ([M-OTf - ] + ): ; found: (2-(3,4-difluorophenoxy)-4,5-difluorophenyl)bis(4-methoxyphenyl) sulfonium trifluoromethanesulfonate (3db): Following the general procedure B, the title compound was obtained as a brown oil, 43.1 mg, 45% yield. (Rf = 0.30, eluent: DCM/MeOH = 15/1). 1 H NMR (600 MHz, CDCl 3 ): δ (m, 4H), (m, 5H), (m, 1H), (m, 1H), (m, 1H), (m, 1H), 3.89 (s, 6H). 13 C NMR (151 MHz, CDCl 3 ): δ 164.8, (dd, J = Hz, 15.1 Hz), (d, J = 9.1 Hz), (dd, J = Hz, 13.6 Hz), (d, J = 7.6 Hz), (dd, J = Hz, 12.8 Hz), (dd, J = Hz, 13.6 Hz), 133.2, (q, J = Hz, - OTf), (d, J = 21.1 Hz), (d, J = 19.6 Hz), 117.4, (m), 112.0, (m), (d, J = 19.6 Hz), (d, J = 22.7 Hz), F NMR (565 MHz, CDCl 3 ): δ (s), (d, J = 21.3 Hz), (d, J = 21.2 Hz), (d, J = 21.3 Hz), (d, J = 21.1 Hz). IR (neat): 3058, 2922, 2848, 1587, 1491, 1411, 1253, 1159, 1028, 958, 832, 756,

31 HRMS: calculated for C 26 H 19 O 3 F 4 S + ([M-OTf - ] + ): ; found: (2-(3,4-difluorophenoxy)-4,5-difluorophenyl)di-p-tolyl sulfonium trifluoromethanesulfonate (3dc): Following the general procedure B, the title compound was obtained as a brown oil, 47.8 mg, 53% yield. (Rf = 0.25, eluent: DCM/MeOH = 15/1). 1 H NMR (600 MHz, CDCl 3 ): δ 7.67 (d, J = 8.5 Hz, 4H), 7.53 (d, J = 8.3 Hz, 4H), (m, 1H), (m, 2H), (m, 1H), (m, 1H), 2.47 (s, 6H). 13 C NMR (151 MHz, CDCl 3 ): δ (dd, J = Hz, 13.6 Hz), (d, J = 7.6 Hz), (dd, J = Hz, 14.3 Hz), (d, J = 7.6 Hz), (dd, J = Hz, 12.1 Hz), (dd, J = Hz, 14.3 Hz), 146.7, 132.6, 131.1, (q, J = Hz, - OTf), (d, J = 22.7 Hz), 119.0, (d, J = 19.6 Hz), (m), (d, J = 19.6 Hz), (m), (d, J = 21.1 Hz), F NMR (565 MHz, CDCl 3 ): δ (s), (d, J = 22.2 Hz), (d, J = 21.6 Hz), (d, J = 22.2 Hz), (d, J = 21.6 Hz). IR (neat): 3054, 2923, 1606, 1490, 1412, 1327, 1255, 1199, 1157, 1028, 958, 809, 754, 698, 636. HRMS: calculated for C 26 H 19 OF 4 S + ([M-OTf - ] + ): ; found: (2-(3,4-difluorophenoxy)-4,5-difluorophenyl)bis(3,4-dimethylphenyl) sulfonium trifluoromethanesulfonate (3dh): Following the general procedure B, the title compound was obtained as a brown oil, 57.5 mg, 61% yield. (Rf = 0.25, eluent: DCM/MeOH = 15/1). 1 H NMR (600 MHz, CDCl 3 ): δ 7.56 (d, J = 1.9 Hz, 2H), 7.47 (d, J = 8.2 Hz, 2H), (m, 2H), (m, 1H), (m, 3H), (m, 1H), 2.36 (d, J = 15.9 Hz, 12H). 13 C NMR (151 MHz, CDCl 3 ): δ (dd, J = Hz, 13.6 Hz), (d, J = 9.1 Hz), (dd, J = Hz, 14.3 Hz), (d, J = 9.1 Hz), (dd, J = Hz, 12.1 Hz), (dd, J = Hz, 13.6 Hz), 145.4, 141.4, 132.8, 131.6, 128.3, (q, J = Hz, - OTf), (d, J 31