3
Table 3. Visible-light-promoted direct trifluoromethylation of
Program of the Chinese Academy of Sciences (No.
free anilines.a
XDB20000000), the Young Elite Scientists Sponsorship Program
by CAST (No. 2015-41), and the Training Programme
Foundation for the Talents of the Zun Yi Science and
Technology Bureau (No. 2015-40).
References and notes
1. (a) Müller, K.; Faeh, C.; Diederich, F. Science 2007, 317, 1881;
(b) Purser, S.; Moore, P. R.; Swallow, S.; Gouverneur V. Chem.
Soc. Rev. 2008, 37, 320; (c) Hagmann, W. K. J. Med. Chem.
2008, 51, 4359; (d) O’Hagan, D. Chem. Soc. Rev. 2008, 37, 308.
2. Kirk, K. L. Org. Process. Res. Dev. 2008, 12, 305.
3. (a) McLoughlin, V. C. R.; Thrower, J. Tetrahedron 1969, 25,
2921; (b) Kobayashi, Y.; Kumadaki, I. Tetrahedron Lett. 1969,
10, 4095.
4. For selected, reviews, see: (a) Tomashenko. O. A.; Grushin, V.
V. Chem. Rev. 2011, 111, 4475; (b) Hollingworth, C.;
Gouverneur, V. Chem. Commun. 2012, 48, 2929; (c) Besset, T.;
Schneider, C.; Cahard, D. Angew. Chem. Int. Ed. 2012, 51, 5048;
(d) Qing, F.-L. Chin. J. Org. Chem. 2012, 32, 815.
aReaction conditions (unless otherwise specified): free anilines 1 (1.2 mmol,
3.0 equiv), CF3I 4 (a solution in 1,2-dichloroethane, 0.4 mmol, 1.0 equiv),
K2CO3 (2.0 equiv), fac-Ir(ppy)3 (1 mol %), 1,2-dichloroethane (4 mL,
together with CF3I solution), argon atmosphere, blue LEDs, room
temperature, 24 hours. All reported yields are those of the isolated products.
bThe reaction was conducted in DMSO with a solution of CF3I in DMSO.
5. (a) Chen, Q.-Y.; Yang, Z.-Y.; Zhao, C.-X.; Qiu, Z.-M. J. Chem.
Soc. Perkin Trans I, 1988, 563; (b) Zhou, Q.-L.; Huang, Y.-Z. J.
Fluorine Chem. 1989, 43, 485; (c) Huang, X.-T.; Chen Q.-Y., J.
Org. Chem. 2001, 66, 4651; (d) Loy, R. N.; Sanford, M. S. Org.
Lett. 2011, 13, 2548; (e) Feng, Z.; Min, Q.-Q.; Zhao, H.-Y.; Gu,
J.-W.; Zhang, X. Angew. Chem. Int. Ed. 2015, 54, 1270; (f)
Natta, K.; Jagadeesh, R. V.; He, L.; Rabeah, J.; Chen, J.;
Taeschler, C.; Ellinger, S.; Zaragoza, F.; Neumann, H.;
Brückner, A.; Beller, M. Angew. Chem. Int. Ed. 2016, 55, 2782.
6. For a review, see: (a) Zhang, C.-P.; Chen, Q.-Y.; Guo, Y.; Xiao,
J.-C.; Gu, Y.-C. Chem. Soc. Rev. 2012, 41, 4536. For the
pioneering work, see: (b) Huang, W. Y.; Ma, W. P. Chin. J.
Chem. 1990, 8, 175; (c) Huang, W. Y.; Ma, W. P.; Wang, W.
Chin. J. Chem. 1992, 10, 180; (d) Huang, W. Y.; Liu, J. T. Chin.
J. Chem. 1993, 11, 370.
On the basis of previous report,8a a possible mechanism is
shown in Scheme 1. The photoredox catalytic cycle is initiated
from the excited state of the photocatalyst *[Ir(ppy)3] (B) with
blue LEDs. Subsequent single electron transfer from B to RFI
generates perfluoroalkyl radical and Ir(IV)(ppy)3 (C). The newly
formed radical intermediate reacts with free aniline to produce
intermediate D, which is oxidized by C, followed by the
7. Yu, L.-C.; Gu, J.-W.; Zhang, S.; Zhang, X. J. Org. Chem. 2017,
82, 3943.
abstraction of
a proton with the base to provide the
perfluoroalkylated products 3 and 6.
8. For selected recent reviews on visible light photoredox catalysis,
see: (a) Shaw, M. H.; Twilton, J.; MacMillan, D. W. C. J. Org.
Chem. 2016, 81, 6898; (b) Skubi, K. L.; Blum, T. R.; Yoon, T. P.
Chem. Rev. 2016, 116, 10035; (c) Kärkäs, M. D.; Porco Jr, J. A.;
Stephenson, C. R. J. Chem. Rev. 2016, 116, 9683; (d) Prier, C.
K.; Rankic, D. A.; MacMillan D. W. C. Chem. Rev. 2013, 113,
5322.
9. For selected photoredox catalyzed fluoroalkylations, see: (a)
Nagib, D. A.; Scott, M. E.; MacMillan, D. W. C. J. Am. Chem.
Soc. 2009, 131, 10875; (b) Nguyen, J. D.; Tucker, J. W.;
Konieczynska, M. D.; Stephenson, C. R. J. J. Am. Chem. Soc.
2011, 133, 4160; (c) Nagib, D. A.; MacMillan, D. W. C. Nature
2011, 480, 224; (d) Wallentin, C.-J.; Nguyen, J. D.; Finkbeiner,
P.; Stephenson, C. R. J. J. Am. Chem. Soc. 2012, 134, 8875; (e)
Lin, Q.; Chu, L.; Qing, F.-L. Chin. J. Chem. 2013, 31, 885; (f)
Xie, J.; Yuan, X.; Abdukader, A.; Zhu, C.; Ma, J. Org. Lett.
2014, 16, 1768.
Scheme 1. Proposed reaction mechanism
In conclusion, we have developed a photoredox-based
method for facile perfluoroalkylation of free anilines from readily
available perfluoroalkyl iodides. The reaction can also extend to
trifluoromethylation of free anilines with high efficiency and
good functional group tolerance, thus providing a facile route for
application in medicinal chemistry.
10. (a) Ye, Y.; Sanford, M. S. J. Am. Chem. Soc. 2012, 134, 9034;
(b) Sladojevich, F.; McNeill, E.; Börgel, J.; Zheng, S.-L.; Ritter,
T. Angew. Chem. Int. Ed. 2015, 54, 3712; (c) Iqbal, N.; Choi, S.;
Ko, E.; Cho, E. J. Tetrahedron Lett. 2015, 53, 2005.
Supplementary Material
Detailed experimental procedures, and characterization data
Acknowledgments
for new compounds.
This work was financially supported by the National Natural
Science Foundation of China (No. 21425208, 21672238,
21332010, and 21421002), the Strategic Priority Research
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