10.1002/anie.201904041
Angewandte Chemie International Edition
COMMUNICATION
a
fundamental organometallic chemistry are undergoing currently in
our laboratory.
ΔG(M11-L/DCE) kcal/mol
(ΔH kcal/mol)
F
F
F
F
F
F
F
F
F
F
F
F
CF3
F
Cu
F3C
F
CF3
CF3
Cu CF3
CF3
Cu CF3
CF3
Acknowledgements
F
F
3c
6
6-ts
7
7
The authors gratefully acknowledge the financial support from
National Natural Science Foundation of China (21625206,
21632009, 21572258, 21421002) and the Strategic Priority
Research Program of the Chinese Academy of Sciences
(XDB20000000).
53.8
(68.1)
53.0
(77.9)
49.7
(63.0)
12-ts
13
6-ts
40.3
(54.2)
6
27.6
(27.8)
7
20.6
(36.4)
14-ts
5
10
Keywords: Fluorine • trifluoromethyl • copper • Cu(III)• reductive
11
7
10
elimination
0.0
(0.0)
[1]
[2]
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Purser, P. R. Moore, S. Swallow, V. Gouverneur, Chem. Soc. Rev. 2008,
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Biology. Wiley-Blackwell: Chichester, U.K., 2009.
3c
-7.1
CF3
CuCF3
8
Cu(CF3)2
9
CF3
10
Cu CF3
13
(16.7)
5
5
8
CF3
F
F
F
F
F3C Cu CF3
CF3
CF3
F3C Cu
F
-33.6
a) W. K. Hagmann, J. Med. Chem. 2008, 51, 4359; b) R. Filler, R. Saha,
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(-20.5)
F
Cu
F
F
9
CF3
F
F
F
F
14-ts
12-ts
11
b
[3]
For selected recent reviews on trifluoromethylation methods, see: a) J.-
A. Ma, D. Cahard, Chem. Rev. 2008, 108, PR1; b) T. Furuya, A. S.
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6-ts
12-ts
14-ts
[4]
[5]
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methods, see: a) S. Roy, B. T. Gregg, G. W. Gribble, V.-D. Le, S. Roy,
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3793; h) X. Yang, G. C. Tsui, Chem. Sci. 2018, 9, 8871.
Figure 5. (a) The calculated activation free energies for the C(sp2)-CF3
reductive elimination of [nBu4N][Cu(Ar)(CF3)3]. (b) Optimized structures for the
transition states 6-ts, 12-ts and 14-ts are shown. Selected bond distances [Å]
are provided.
Collectively, both experimental results and DFT calculation
suggest that the mechanism for the C(sp2)-CF3 reductive
elimination from complex 3 occurs through a classic concerted
bond-forming process via a three-membered ring transition state,
as shown in pathway D, Figure 3.
In summary, we have synthesized, for the first time, a family
of stable square planar aryl(tris(trifluoromethyl))cuprate(III)
complexes [nBu4N] [Cu(Ar)(CF3)3] 3a-f, that might act as key
intermediates in copper-mediated trifluoromethylation reactions.
The thermal reactions of these complexes were then studied in
detail. These results combined with DFT calculation indicate that
the C(sp2)-CF3 reductive elimination from complexes
[nBu4N][Cu(Ar)(CF3)3] proceeds through a concerted carbon-
carbon bond-forming pathway from the four-coordinated Cu(III)
metal center via a three-membered ring transition state. The
results of this study reveal the extraordinary reactivity of the
[6]
For selected examples on copper-mediated trifluoromethylation of aryl
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1174; c) T. Liu, Q. Shen, Org. Lett. 2011, 13, 2342; d) J. Xu, D.-F. Luo,
B. Xiao, Z.-J. Liu, T.-J. Gong, Y. Fu, L. Liu, Chem. Commun. 2011, 47,
4300; e) C.-P. Zhang, J. Cai, C.-B. Zhou, X.-P. Wang, X. Zheng, Y.-C.
Gu, J.-C. Xiao, Chem. Commun. 2011, 47, 9516; f) Y. Ye, M. S. Sanford,
J. Am. Chem. Soc. 2012, 134, 9034; g) N. D. Litvinas, P. S. Fier, J. F.
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Shibata, Org. Lett. 2015, 17, 1632.
[7]
[8]
For reviews on mechanism of Cu(III) chemistry, see: a) A. J. Hickman,
M. S. Sanford, Nature, 2012, 484, 177; b) N. Yoshikai, E. Nakamura,
Chem. Rev. 2012, 112, 2339; c) A. Casitas, X. Ribas, Chem. Sci. 2013,
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organocopper(III) complexes bearing both an aryl and
trifluoromethyl group, which has not been described previously,
despite the long history of Cu-mediated trifluoromethylation
a
reactions.
Further
characterization
of
high-valent
For studies on mechanism of copper-mediated trifluoromethylation of
aryl halides: a) Lishchynskyi, A.; Novikov, M. A.; Martin, E.; Escudero-
Adan, R. C.; Novak, P.; Grushin, V. V. J. Org. Chem. 2013, 78, 11126;
trifluoromethylated organocopper species and studies of their
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