dichloromethane or DMSO (CHCl3 δ 7.26, (CH3)2CO δ 2.05, DMSO
δ 2.50). Chemical shifts for carbon are reported in parts per
million relative to chloroform, dichloromethane or DMSO (CHCl3 δ
77.0, (CH3)2CO δ 29.84, DMSO δ 39.52). Data are represented as
follows: chemical shift, multiplicity (br = broad, s = singlet, d =
doublet, t = triplet, q = quartet, m = multiplet), coupling constants
in Hertz (Hz), integration. Mass spectra were recorded on a
Shimadzu GCMS-QP2010 Ultra. IR spectra were recorded on
TENSOR (27) Series FT-IR 241.Spectrometers.
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General procedure for the C-S Cyclization
Under a N2 atmosphere, allkyl ethanethioate 1 (0.1 mmol),
Pd(OAc)2 (2.2 mg, 0.01 mmol), PtBu3∙HBF4 (5.8 mg, 0.02 mmol),
Ag2CO3 (55.3 mg, 0.2 mmol) , H2O (10 μL) and dry toluene (1 mL)
[or CH3COOH (1 mL) instead of toluene and without H2O for
six-membered products] were added to a flame-dried Schlenk
tube. The resulting mixture was stirred at 120 oC for 12 hours,
H2O and ethyl acetate were added and the organic layers were
separated. The aqueous phase was extracted with ethyl acetate.
The combined organic layer was dried over Na2SO4. After
evaporation of solvent, the residue was purified by column
chromatography to give the corresponding products 2.
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6-methoxy-2,3-dihydrobenzo[b]thiophene (2a): Prepared
following general procedure using phenylethyl ethanethioate 1a
(21.3 mg, 0.1 mmol), Pd(OAc)2 (2.2 mg, 0.01 mmol), PtBu3∙HBF4
(5.8 mg, 0.02 mmol), Ag2CO3 (55.3 mg, 0.2 mmol), H2O (10 μL) and
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C.-L.; Zhang, X.-G.; Tang, R.-Y.; Zhoug, P.; Li, J.-H. J. Org. Chem. 2010,
75, 7037. (b) Han, H.; Zhao, W.; Song, J.; Li, C.; Wang, H.; J. Org.
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o
toluene (1 mL), the reaction was stirred at 120 C for 12 h giving
2a (13.1 mg) in 79% yield as a colorless liquid by column
chromatography (PE/EA = 20/1). The product is volatile, should be
treated carefully. 1H NMR (400 MHz, CDCl3) δ 7.07 (d, J = 8.2 Hz,
1H), 6.79 (d, J = 2.3 Hz, 1H), 6.56 (dd, J = 8.2, 2.3 Hz, 1H), 3.77 (s,
3H), 3.36 (t, J = 7.7 Hz, 2H), 3.21 (t, J = 7.7 Hz, 2H); 13C NMR (100
MHz, CDCl3) δ 159.28, 142.90, 132.05, 124.62, 109.98, 107.70,
55.41, 35.22, 33.98. IR (KBr) ν 3051, 2996, 2833, 1595, 1575, 1484,
1463, 1280, 1242, 1224, 1194, 1180, 1054, 1029, 884, 844, 802,
756 cm-1; HRMS (EI) for C9H10OS Calculated: 166.0452, found:
166.0453.
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Gaunt, M. J. J. Am. Chem. Soc. 2008, 130, 16184. (b) Cho, S. H.; Yoon,
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Supporting Information
The supporting information for this article is available on the
[12] (a) Wang, X.; Lu, Y.; Dai, H.-X.; Yu, J.-Q. J. Am. Chem. Soc. 2010, 132,
12203. (b) Xiao, B. Gong, T.-J.; Liu, Z.-J.; Liu, J.-H., Liu, D.-F.; Xu, J. Liu,
L. J. Am. Chem. Soc. 2011, 133, 9250. (c) Zheng, Y.-W.; Ye, P.; Chen, B.;
Meng, Q.-Y.; Feng, K.; Wang, W.; Wu, L.-Z.; Tung, C.-H. Org. Lett.
2017, 19, 2206.
Acknowledgement
We acknowledge financial support from the National Key
Research and Development Program of China (2017YFD0200500),
NSFC (21722202, 21672069, 21472050, 21502054 for M.W.),
S&TCSM of Shanghai (Grant 18JC1415600), Professor of Special
Appointment (Eastern Scholar) at Shanghai Institutions of Higher
Learning, and National Program for Support of Top-notch Young
Professionals.
[13] The C-H functionalization using disulfides, see: (a) Lin, C.; Li, D.;
Wang, B.; Yao, J.; Zhang, Y. Org. Lett. 2015, 17, 1328. (b) Lin, C.; Yu,
W.; Yao, J.; Wang, B.; Liu, Z.; Zhang, Y. Org. Lett. 2015, 17, 1340.
[14] (a) Xiao, X.; Xue, J.; Jiang, X. Nature. Commun. 2018‚ 9‚
DOI:10.1038/s41467-018-04306-5. (b) Xiao, X.; Jiang, X. Angew.
Chem. Int. Ed. 2016‚ 56‚ 14121. (c) Li, Y.; Wang, M.; Jiang, X. ACS
Catalysis 2017, 7, 7587. (d) Qiao, Z.; Jiang, X. Org. Lett. 2016, 18,
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(f) Li, Y.; Wang, M.; Jiang, X. Chem.-Eur. J. 2015, 21, 16059. (g) Wang,
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Review: (h) Qiao, Z.; Jiang, X. Org. Biomol. Chem. 2017, 15, 1942.
[15] CCDC 1839554 (2h) and CCDC 1839574 (3i) can be obtained free of
charge from The Cambridge Crystallographic Data Centre via
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