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(15A150021).
Notes and references
1 (a) R. Martin and S. L. Buchwald, Acc. Chem. Res., 2008, 41,
1461; (b) D. W. Ma and Q. A. Cai, Acc. Chem. Res., 2008, 41,
1450; (c) J. F. Hartwig, Acc. Chem. Res., 2008, 41, 1534; (d)
I. P. Beletskaya and A. V. Cheprakov, Coord. Chem. Rev.,
2004, 248, 2337; (e) G. Evano, N. Blanchard and M. Toumi,
Chem. Rev., 2008, 108, 3054; (f) S. V. Ley and
A. W. Thomas, Angew. Chem., Int. Ed., 2003, 42, 5400.
2 (a) A. Takemiya and J. F. Hartwig, J. Am. Chem. Soc., 2006,
128, 6042; (b) S. B. Herzon and J. F. Hartwig, J. Am. Chem.
Soc., 2007, 129, 6690; (c) Y. Oe, T. Ohta and Y. Ito, Chem.
Commun., 2004, 1620; (d) J. A. Bexrud, J. D. Beard,
D. C. Leitch and L. L. Schafer, Org. Lett., 2005, 7, 1959; (e)
M. R. Crimmin, I. J. Casely and M. S. Hill, J. Am. Chem.
Soc., 2005, 127, 2042; (f) C. F. Bender and
R. A. Widenhoefer, J. Am. Chem. Soc., 2005, 127, 1070; (g)
J. Zhang, C.-G. Yang and C. He, J. Am. Chem. Soc., 2006,
128, 1798; (h) X. Zhang and A. Corma, Chem. Commun.,
2007, 3080; (i) J. Michaux, V. Terrasson, S. Marque,
J. Wehbe, D. Prim and J.-M. Campagne, Eur. J. Org. Chem.,
2007, 2601; (j) G. A. Olah, Angew. Chem., Int. Ed. Engl.,
1995, 34, 1393; (k) K. Komeyama, T. Morimoto and
K. Takaki, Angew. Chem., Int. Ed., 2006, 45, 2938; (l)
A. S. K. Hashmi and G. J. Hutchings, Angew. Chem., Int.
Ed., 2006, 45, 7896.
Scheme 4 Examples of quinoline derivatives synthesis. aAll reactions
were carried out by employing substrate 1 (1.0 mmol), and HOTf (5.0
mol%) in toluene (2 mL) at 50 ꢀC in air for 4 h. bYields after column
chromatographic purification with silica gel.
To extend the applicability of our reaction, we next turned
our attention to the Brønsted acid catalyzed intramolecular
cyclization of an amine containing a substituted alkyne in the
presence of 5 mol% of HOTf for 4 h in toluene, the results
shown in Scheme 4. Under the standard reaction conditions,
the substrates with electron-donating or -withdrawing groups
were successfully transformed into the corresponding quino-
lines (4a–k). The –CN, –COOMe substituents on the aryl part of
the amine (4d/e) were tolerated in this transformation. In the
case of 4d and 4e, lower yield were obtained, which might be
attributed to the electronic properties of the substituent on the
amine. The efficiency and functional group tolerance of this
procedure have been demonstrated by synthesizing a number of
substituted quinolines. This method should nd numerous
applications, including in the industrial eld. Further investi-
gations toward the scope of the reaction, a detailed mechanism,
and applications in organic synthesis are ongoing in our
laboratory.
3 J. Seayad, A. Tillack, C. G. Hartung and M. Beller, Adv. Synth.
Catal., 2002, 344, 795.
4 (a) T. E. Muller and M. Beller, Chem. Rev., 1998, 98, 675; (b)
S. Kobayashi, I. Komoto and J.-I. Matsuo, Adv. Synth.
Catal., 2001, 343, 71–74.
5 (a) B. Schlummer and J. F. Hartwig, Org. Lett., 2002, 4, 1471;
(b) M. Katwatsura and J. F. Hartwig, J. Am. Chem. Soc., 2000,
122, 9546.
6 M. Beller, O. R. Thiel and H. Trauthwein, Synlett, 1999, 243.
7 H. Hart and J. R. Kosak, J. Org. Chem., 1962, 27, 116.
8 L. L. Anderson, J. Arnold and R. G. Bergman, J. Am. Chem.
Soc., 2005, 127, 14542.
Conclusions
In conclusion, we have developed a Brønsted acid catalyzed
intermolecular hydroamination of alkenes and alkynes with
anilines and intramolecular cyclization of an amine containing
a substituted alkyne transformed into the corresponding
quinolines under mild conditions. Some functional groups,
such as the NO2, CN substitution on arenes can be tolerated.
The use of HOTf for these reactions provides a simple alterna-
tive to toxic and precious metals. The raw materials are readily
available from commercial vendors, to give synthetically useful
structures efficiently. The use of a single catalytic system to
mediate chemical transformations in a synthetic operation is
important for the development of new atom-economic strate-
gies. We found that this strategy is efficient in building complex
structures from simple starting materials in an environmentally
benign fashion.
9 Z. Li, J. Zhang, C. Brouwer, C.-G. Yang, N. W. Reich and
C. He, Org. Lett., 2006, 8, 4175.
¨
10 (a) T. E. Muller and M. Beller, Chem. Rev., 1998, 98, 675; (b)
D. M. Roundhill, Chem. Rev., 1992, 92, 1; (c) H. E. Bryndza
and W. Tam, Chem. Rev., 1988, 88, 1163; (d)
H. Trauthwein, A. Tillack and M. Beller, Chem. Commun.,
1999, 2029; (e) M. Beller, H. Trauthwein, M. Eichberger,
¨
C. Breindl, J. Herwig, T. E. Muller and O. R. Thiel, Chem.–
Eur. J, 1999, 5, 1306; (f) M. Beller, H. Trauthwein,
¨
M. Eichberger, C. Breindl, T. E. Muller and A. Zapf, J.
Organomet. Chem., 1998, 566, 277; (g) M. Beller,
M. Eichberger and H. Trauthwein, Angew. Chem., Int. Ed.
Acknowledgements
¨
Engl., 1997, 36, 2225; (h) T. E. Muller, K. C. Hultzsch,
This paper is supported by the Science Foundation of Nanyang
M. Yus, F. Foubelo and K. Tada, Chem. Rev., 2008, 108, 3795.
¨
Normal University (ZX2013026) and National Natural Science 11 S. Kramer, K. Dooleweerdt, T. Lindhardt, M. Rottlander and
Foundation of China (21302105), and Research fund for the key
T. Skrydstrup, Org. Lett., 2009, 11, 4208.
40952 | RSC Adv., 2015, 5, 40950–40952
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