Table 3 Exploration of the scope of the Fe-catalyzed direct C–H
activation reactiona
2008, 47, 2880; (c) Z. Wang, Y. Zhang, H. Fu, Y. Jiang and
Y. Zhao, Org. Lett., 2008, 10, 1863; (d) K. Komeyama,
T. Morimoto and K. Takaki, Angew. Chem., Int. Ed., 2006, 45,
2938.
4 (a) C. M. Rao Volla and P. Vogel, Org. Lett., 2009, 11, 1701;
(b) A. Mayer and C. Bolm, in Iron Catalysis in Organic Chemistry,
ed. B. Plietker, Wiley-VCH, New York, 2008, p. 73.
5 J. Norinder, A. Matsumoto, N. Yoshikai and E. Nakamura,
J. Am. Chem. Soc., 2008, 130, 5858.
6 Z. Li, L. Cao and C.-J. Li, Angew. Chem., Int. Ed., 2007, 46, 6505.
7 J. Wen, J. Zhang, S.-Y. Chen, J. Li and X.-Q. Yu, Angew. Chem.,
Int. Ed., 2008, 47, 8897.
8 (a) D. Alberico, M. E. Scott and M. Lautens, Chem. Rev., 2007,
107, 174; (b) M. Lersch and M. Tilset, Chem. Rev., 2005, 105, 2471;
(c) J. A. Labinger and J. E. Bercaw, Nature, 2002, 417, 507;
(d) V. Ritleng, C. Sirlin and M. Pfeffer, Chem. Rev., 2002, 102,
1731.
9 (a) Z.-H. Guan, Z.-H. Ren, S. M. Spinella, S. Yu, Y.-M. Liang and
X. Zhang, J. Am. Chem. Soc., 2009, 131, 729, and references
therein; (b) Z.-H. Guan, K. Huang, S. Yu and X. Zhang, Org.
Lett., 2009, 11, 481; (c) S. Oi, S. Fukita and Y. Inoue, Chem.
Commun., 1998, 2439; (d) D. A. Colby, R. G. Bergman and
J. A. Ellman, Chem. Rev., 2010, 110, DOI: 10.1021/cr900005n.
a
Reaction conditions: 1 (0.3 mmol), FeCl3 (4.8 mg, 10 mol%),
Cu(OAc)2ÁCuCl2 (142 mg, 0.45 mmol), K2CO3 (124 mg, 0.9 mmol),
in DMF (3 mL) at 120 1C for 2 h. b Isolated yields (average of two
runs). c K2CO3 (248 mg, 1.8 mmol) was used as the base and Na2SO4
(85 mg, 0.6 mmol) was used as the additive. d Bu4NCl (166 mg,
0.6 mmol) was used as the additive.
¨
10 (a) I. Ozdemir, S. Demir, B.
C¸ etinkaya, C. Gourlaouen,
F. Maseras, C. Bruneau and P. H. Dixneuf, J. Am. Chem. Soc.,
2008, 130, 1156; (b) Y. Matsuura, M. Tamura, T. Kochi, M. Sato,
N. Chatani and F. Kakiuchi, J. Am. Chem. Soc., 2007, 129, 9858.
11 For iron-catalyzed C–H bond oxidation reaction, see: (a) H. Egami
and T. Katsuki, J. Am. Chem. Soc., 2009, 131, 6082;
(b) P. Stavropoulos, R. Celenligil-Cetin and A. E. Tapper, Acc.
Chem. Res., 2001, 34, 745.
12 (a) T. Kawasaki and K. Higuchi, Nat. Prod. Rep., 2005, 22, 761;
(b) M. Somei and F. Yamada, Nat. Prod. Rep., 2005, 22, 73.
13 (a) J. Yang, H. Wu, L. Shen and Y. Qin, J. Am. Chem. Soc., 2007,
129, 13794; (b) S. B. Herzon and A. G. Myers, J. Am. Chem. Soc.,
2005, 127, 5342; (c) P. S. Baran, C. A. Guerrero,
B. D. Hafensteiner and N. B. Ambhaikar, Angew. Chem., Int.
Ed., 2005, 44, 3892.
14 (a) G. R. Humphrey and J. T. Kuethe, Chem. Rev., 2006, 106,
2875; (b) S. Cacchi and G. Fabrizi, Chem. Rev., 2005, 105, 2873.
15 (a) E. M. Beccalli, G. Broggini, M. Martinelli and S. Sottocornola,
Chem. Rev., 2007, 107, 5318; (b) P. Thansandote and M. Lautens,
Chem.–Eur. J., 2009, 5874.
Scheme 1 Proposed mechanism.
activation reaction shows high functional group tolerance and
exhibits different properties from the palladium catalyzed
reactions of this type. The cheap and environmentally benign
iron catalyst combined with the highly active Cu(OAc)2ÁCuCl2
makes this C–H activation reaction practical and attractive in
organic synthesis.
16 S. Wurtz, S. Rakshit, J. J. Neumann, T. Droge and F. Glorius,
¨
Angew. Chem., Int. Ed., 2008, 47, 7230.
¨
17 Fe(II) shows identical reactivity with Fe(III), probably due to rapid
oxidation of Fe(II) to give Fe(III) in air during the reaction.
18 R. Bernini, G. Fabrizi, A. Sferrazza and S. Cacchi, Angew. Chem.,
Int. Ed., 2009, 48, 8078.
19 N-Aryl enaminones, such as 4-(phenyl amino)pent-3-en-2-one,
showed diminished reactivity and formed only 16% yield of desired
product under our standard reaction conditions.
The authors gratefully acknowledge the NSFC
(NSFC20732002, NSFC20090443, NSFC20872052) for
financial support.
20 In some cases, the decomposition of the substrate was inhibited
when Na2SO4 was used as a dehydrant.
21 Bu4NCl was reported to improve the efficiency in Pd-catalyzed
coupling reactions, see: R. C. Larock, Pure Appl. Chem., 1990, 62,
653.
22 In palladium catalyzed C–H activation reaction, a significant
amount of the debrominated indole product was observed; see
ref. 16.
23 (a) N. Kudo, M. Perseghini and G. C. Fu, Angew. Chem., Int. Ed.,
2006, 45, 1282; (b) G. A. Molander and B. Biolatto, J. Org. Chem.,
2003, 68, 4302; (c) G. A. Molander, B. W. Katona and
F. Machrouhi, J. Org. Chem., 2002, 67, 8416.
Notes and references
1 For general reviews, see: (a) A. Correa, O. G. Mancheno and
C. Bolm, Chem. Soc. Rev., 2008, 37, 1108; (b) S. Enthaler, K. Junge
and M. Beller, Angew. Chem., Int. Ed., 2008, 47, 3317;
(c) B. D. Sherry and A. Furstner, Acc. Chem. Res., 2008, 41,
1500; (d) C. Bolm, J. Legros, J. Le Paih and L. Zani, Chem. Rev.,
2004, 104, 6217.
2 (a) G. Cahiez, L. Foulgoc and A. Moyeux, Angew. Chem., Int. Ed.,
2009, 48, 2969; (b) T. Hatakeyama and M. Nakamura, J. Am.
´
Chem. Soc., 2007, 129, 9844; (c) A. Guerinot, S. Reymond and
¨
24 S. L. Buchwald and C. Bolm, Angew. Chem., Int. Ed., 2009, 48, 5586.
25 (a) K. Kohno, K. Nakagawa, T. Yahagi, J.-C. Choi, H. Yasuda
and T. Sakakura, J. Am. Chem. Soc., 2009, 131, 2784; (b) H. Li,
J. Yang, Y. Liu and Y. Li, J. Org. Chem., 2009, 74, 6797;
(c) G. Brasche and S. L. Buchwald, Angew. Chem., Int. Ed.,
2008, 47, 1932.
J. Cossy, Angew. Chem., Int. Ed., 2007, 46, 6521; (d) J. Kischel,
K. Mertins, D. Michalik, A. Zapf and M. Beller, Adv. Synth.
Catal., 2007, 349, 865; (e) L. K. Ottesen, F. Ek and R. Olsson, Org.
Lett., 2006, 8, 1771.
3 (a) A. C. Mayer, A.-F. Salit and C. Bolm, Chem. Commun., 2008,
5975; (b) A. Correa, M. Carril and C. Bolm, Angew. Chem., Int. Ed.,
ꢀc
This journal is The Royal Society of Chemistry 2010
Chem. Commun., 2010, 46, 2823–2825 | 2825