RSC Advances
Communication
3 (a) T. Furuya, A. S. Kamlet and T. Ritter, Nature, 2011, 473,
470; (b) R. J. Lundgren and M. Stradiotto, Angew. Chem.,
Int. Ed., 2010, 49, 9322; (c) V. V. Grushin, Acc. Chem. Res.,
2010, 43, 160; (d) O. A. Tomashenko and V. V. Grushin,
Chem. Rev., 2011, 111, 4475; (e) S. Roy, B. T. Gregg,
G. W. Gribble, V.-D. Le and S. Roy, Tetrahedron, 2011, 67,
2161; (f) X.-F. Wu, H. Neumann and M. Beller, Chem.–
Asian. J, 2012, 7, 1744.
4 (a) V. V. Grushin and W. J. Marshall, J. Am. Chem. Soc., 2006,
128, 12644; (b) H. Morimoto, T. Tsubogo, N. D. Litvinas and
J. F. Hartwig, Angew. Chem., Int. Ed., 2012, 51, 536; (c)
N. D. Litvinas, P. S. Fier and J. F. Hartwig, Angew. Chem.,
Int. Ed., 2011, 50, 3793; (d) O. A. Tomashenko,
Scheme
2 Trifluoromethylation of vinylboronic acid and vinyl-
trifluoroborates; E/Z ratio analyzed by 1H NMR. aReaction condition:
substrate (1.0 equiv., 0.25 mmol), CuCl (1.0 equiv.), NaSO2CF3
(3.0 equiv.), TBHP (5.0 equiv.), CH2Cl2/MeOH/H2O at 0–23 ꢁC for 6–
12 h. bYields determined by 19F NMR analysis. cIsolated yield.
´
´
E. C. Escudero-Adan, M. Martınez Belmonte and
V. V. Grushin, Angew. Chem., Int. Ed., 2011, 50, 7655; (e)
V. V. Grushin and W. J. Marshall, J. Am. Chem. Soc., 2006,
128, 4632; (f) G. G. Dubinina, H. Furutachi and D. A Vicic,
J. Am. Chem. Soc., 2008, 130, 8600.
affording good to excellent yields (Table 2, 2n, 89%; 2o, 55%).
Besides, when we employed heteroaryltriuoroborates (pyridyl,
indole, benzofuryl and thiobenzofuryl) they afforded moderate
to excellent yields of the corresponding triuoromethylated
products (Table 2, 2p, 85%; 2q, 55%; 2r, 91%; 2s, 54%). Addi-
tionally, we tested pinacol esters 1h-BPin and 1t-BPin under our
reaction condition, however they gave the corresponding tri-
uoromethylated products 2h (28%) and 2t (30%) in poor yield
(Table 2).
We then extended our studies into vinylboronic acids (3a–d)
and the corresponding triuoroborates (4a–d) (Scheme 2). The
potassium vinyltriuoroborates 4a–d used in this study were
prepared from the corresponding boronic acids 3a–d using
KHF2 in MeOH/H2O in good yields (65–85%) and their struc-
tures were conrmed by 1H, 13C, and 19F NMR analyses
(Scheme 2).23 Excellent yields were obtained when we used
either boronic acid or triuoroborate (Scheme 2, 5a–d). The
resulting triuoromethyl substituted alkenes were observed as a
mixture of E/Z isomers (5b, E : Z ¼ 25 : 1 from 3b; E : Z ¼ 20 : 1
from 4b; 5c, E : Z ¼ 16 : 1 from 3c; E : Z ¼ 13 : 1 from 4c; 5d,
E : Z ¼ 12 : 1 from 3d; E : Z ¼ 3 : 1 from 4d) (Scheme 2).
In summary, we report a convenient Cu-mediated tri-
uoromethylation of aryl-, heteroaryltriuoroborates, vinyl-
boronic acids and vinyltriuoroborates, using less expensive and
stable CF3SO2Na as the CF3 source by in situ generation of CF3c as
the active triuoromethylating agent. The protocol is robust and
the reactions work in CH2Cl2/H2O/MeOH at room temperature.
5 (a) M. Oishi, H. Kondo and H. Amii, Chem. Commun., 2009,
1909; (b) H. Kondo, M. Oishi, K. Fujikawa and H. Amii,
Adv. Synth. Catal., 2011, 353, 1247.
6 B. A. Khan, A. E. Buba and L. J. Gooßen, Chem.–Eur. J, 2011,
17, 2689.
`
7 P. Novak, A. Lishchynskyi and V. V. Grushin, Angew. Chem.,
Int. Ed., 2012, 51, 7767.
8 (a) J. Xu, D. F. Luo, B. Xiao, Z. J. Liu, T. J. Gong, Y. Fu and
L. Liu, Chem. Commun., 2011, 47, 4300; (b) C.-P. Zhang,
J. Cai, C.-B. Zhou, X.-P. Wang, X. Zheng, Y.-C. Gu and
J.-C. Xiao, Chem. Commun., 2011, 47, 9516.
9 (a) T. F. Liu and Q. L. Shen, Org. Lett., 2011, 13, 2342; (b)
T. F. Liu, X. X. Shao, Y. M. Wu and Q. L. Shen, Angew.
Chem., Int. Ed., 2012, 51, 540.
10 (a) L. L. Chu and F. L. Qing, Org. Lett., 2010, 12, 5060; (b)
T. D. Senecal, A. T. Parsons and S. L. Buchwald, J. Org.
Chem., 2011, 76, 1174; (c) N. D. Litvinas, P. S. Fier and
J. F. Hartwig, Angew. Chem., Int. Ed., 2012, 51, 536.
11 Pd(II)-Catalyzed ortho triuoromethylations, see: (a)
X. S. Wang, L. Truesdale and J. Q. Yu, J. Am. Chem. Soc.,
2010, 132, 3648; (b) N. D. Ball, J. W. Kampf and
M. S. Sanford, J. Am. Chem. Soc., 2010, 132, 2878; (c)
X.-G. Zhang, H.-X. Dai, M. Wasa and J. Q. Yu, J. Am.
Chem. Soc., 2012, 134, 11948; (d) L.-S. Zhang, K. Chen,
B.-J. Li, Q.-Y. Guo, J.-B. Wei and Z.-J. Shi, Org. Lett., 2013,
15, 10; Cu(I)-Catalyzed ortho triuoromethylations, see:
(e) S. Cai, C. Chen, Z. Sun and C. Xi, Chem. Commun.,
2013, 49, 4552; (f) E. Mejia and A. Togni, ACS Catal.,
2012, 2, 521; (g) F. Pan and Z. Shi, Acta Chim. Sin., 2012,
70, 1679.
Notes and references
1 (a) M. Schlosser, Angew. Chem., Int. Ed., 2006, 45, 5432; (b) 12 E. J. Cho, T. D. Senecal, T. Kinzel, Y. Zhang, D. A. Watson and
¨
K. Muller, C. Faeh and F. Diederich, Science, 2007, 317,
S. L. Buchwald, Science, 2010, 328, 1679.
1881; (c) W. K. Hagmann, J. Med. Chem., 2008, 51, 4359; (d) 13 (a) B. R. Langlois, E. Laurent and N. Roidot, Tetrahedron
K. L. Kirk, Org. Process Res. Dev., 2008, 12, 305; (e)
S. Purser, P. R. Moore, S. Swallow and V. Gouverneur,
Chem. Soc. Rev., 2008, 37, 320.
2 (a) G. K. S. Prakash and S. Chacko, Curr. Opin. Drug Discovery
Dev., 2008, 11, 793; (b) I. Kieltsch, P. Eisenberger, K. Stanek
and A. Togni, Chimia, 2008, 62, 260.
Lett., 1991, 32, 7525; (b) B. R. Langlois, E. Laurent and
N. Roidot, Tetrahedron Lett., 1992, 33, 1291.
14 (a) D. A. Nagib and D. W. C. MacMillan, Nature, 2011, 480,
224; (b) Y. Ji, T. Brueckl, R. D. Baxter, Y. Fujiwara,
I. B. Seiple, S. Su, D. G. Blackmond and P. S. Baran, Proc.
Natl. Acad. Sci. U. S. A., 2011, 108, 14411.
6498 | RSC Adv., 2014, 4, 6496–6499
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