D
W. Zhou et al.
Letter
Synlett
(7) Choi, H.; Doyle, M. P. Chem. Commun. 2007, 745.
FeCl2
(8) Li, F.; Chen, J.; Zhang, Q. H.; Wang, Y. Green Chem. 2008, 10, 553.
(9) Kamata, K.; Kasai, J.; Yamaguchi, K.; Mizuno, N. Org. Lett. 2004,
6, 3577.
DMSO
N
N
O2
N
H
H
M
(10) Jawale, D. V.; Gravel, E.; Shah, N.; Dauvois, V.; Li, H. Y.;
Namboothiri, I. N. N.; Doris, E. Chem. Eur. J. 2015, 21, 7039.
(11) Cui, X. J.; Li, Y. H.; Bachmann, S.; Scalone, M.; Surkus, A.-E.;
Junge, K.; Topf, C.; Beller, M. J. Am. Chem. Soc. 2015, 137, 10652.
(12) Iosub, A. V.; Stahl, S. S. Org. Lett. 2015, 17, 4404.
(13) Wendlandt, A. E.; Stahl, S. S. J. Am. Chem. Soc. 2014, 136, 11910.
(14) (a) Wu, J. J.; Talwar, D.; Johnston, S.; Yan, M.; Xiao, J. L. Angew.
Chem. Int. Ed. 2013, 52, 6983. (b) Talwar, D.; Gonzalez-de-
Castro, A.; Li, H. Y.; Xiao, J. L. Angew. Chem. Int. Ed. 2015, 54,
5223.
N
Scheme 1 A possible pathway for the oxidative dehydrogenation of
tetrahydroquinolines catalyzed by FeCl2/DMSO where M may be Fe2+ or H+
Acknowledgment
(15) Yamaguchi, R.; Ikeda, C.; Takahashi, Y.; Fujita, K. J. Am. Chem.
Soc. 2009, 131, 8410.
(16) Chakraborty, S.; Brennessel, W. W.; Jones, W. D. J. Am. Chem.
Soc. 2014, 136, 8564.
We thank Changzhou University (WZ) and the Thailand Research
Fund (PT) for research fellowships.
(17) Xu, R. B.; Chakraborty, S.; Yuan, H. M.; Jones, W. D. ACS Catal.
2015, 5, 6350.
(18) Zhang, E. L.; Tian, H. W.; Xu, S. D.; Yu, X. C.; Xu, Q. Org. Lett.
2013, 15, 2704.
(19) MacGregor, W. S. Ann. N. Y. Acad. Sci. 1967, 141, 3.
(20) Typical Procedure
Supporting Information
Supporting information for this article is available online at
S
u
p
p
ortioInfgrmoaitn
S
u
p
p
ortiInfogrmoaitn
To a Schlenk tube equipped with a magnetic stir bar were added
8-methyl-1,2,3,4-tetrohydroquinoline (0.50 mmol), FeCl2 (1.9
mg, 1.5·10–2 mmol), DMSO (31.2 mg, 0.4 mmol), and p-xylene (1
mL). The reaction mixture was stirred at 110 °C under an
oxygen atmosphere using a balloon and monitored by TLC. After
the reaction, the mixture was cooled to room temperature and
purified using flash chromatography (hexane–EtOAc, 10:1) to
give the corresponding product 8-methylquinoline in 70% yield.
8-Methylquinoline
References and Notes
(1) (a) Wang, Z. H.; Tonks, I.; Belli, J.; Jensen, C. M. J. Organomet.
Chem. 2009, 694, 2854. (b) Yao, W. B.; Zhang, Y. X.; Jia, X. Q.;
Huang, Z. Angew. Chem. Int. Ed. 2014, 53, 1390.
(2) Damodara, D.; Arundhathi, R.; Likhar, P. R. Adv. Synth. Catal.
2014, 356, 189.
(3) Mikami, Y.; Ebata, K.; Mitsudome, T.; Mizugaki, T.; Jitsukawa,
K.; Kaneda, K. Heterocycles 2011, 82, 1371.
(4) Hara, T.; Mori, K.; Mizugaki, T.; Ebitani, K.; Kaneda, K. Tetrahe-
dron Lett. 2003, 44, 6207.
(5) Muthaiah, S.; Hong, S. H. Adv. Synth. Catal. 2012, 354, 3045.
(6) (a) Yamaguchi, K.; Mizuno, N. Chem. Eur. J. 2003, 9, 4353.
(b) Yamaguchi, K.; Mizuno, N. Angew. Chem. Int. Ed. 2003, 42,
1480.
Colorless oil. 1H NMR (400 MHz, CDCl3): δ = 8.93 (m, 1 H), 8.10
(m, 1 H), 7.64 (d, J = 4.0 Hz, 1 H), 7.54 (m, 1 H), 7.43–7.35 (m, 2
H) 2.82 (s, 3 H). 13C NMR (100 MHz, CDCl3): δ = 149.2, 147.3,
137.1, 136.3, 129.6, 128.3, 126.3, 125.9, 120.8, 18.2. HRMS: m/z
calcd for [C10H9N + H+]: 144.0813; found: 144.0813.
© Georg Thieme Verlag Stuttgart · New York — Synlett 2016, 27, A–D