Communications
and Cs CO3 (1.3 g, 4.0 mmol). Iodobenzene (224 mL, 2.0 mmol,
Taillefer, Adv. Synth. Catal. 2006, 348, 499; c) H. J. Cristau, A.
Ouali, J. F. Spindler, M. Taillefer, Chem. Eur. J. 2005, 11, 2483;
d) H. J. Cristau, P. P. Cellier, J. F. Spindler, M. Taillefer, Chem.
Eur. J. 2004, 10, 5607; e) H. J. Cristau, P. P. Cellier, J. F. Spindler,
M. Taillefer, Eur. J. Org. Chem. 2004, 695; f) H. J. Cristau, P. P.
Cellier, S. Hamada, J. F. Spindler, M. Taillefer, Org. Lett. 2004, 6,
913.
2
1
equiv) or bromobenzene (212 mL, 2.0 mmol, 1 equiv) was added
under nitrogen followed by anhydrous DMF (2 mL). The tube was
sealed under nitrogen, and the mixture was heated to 908C and stirred
for 30 h. After cooling to room temperature, the mixture was diluted
with dichloromethane and filtered. The filtrate was washed twice with
water, and the combined aqueous phases were extracted twice with
dichloromethane. The organic layers were combined, dried over
Na SO , and concentrated to yield the crude product, which was
[5] See reference [1] and a) H. C. Goodbrandt, J. Org. Chem. 1999,
64, 670; b) A. Klapars, J. C. Antilla, S. L. Buchwald, J. Am. Chem.
Soc. 2001, 123, 7727; c) R. K. Gujadhur, C. G. Bates, D. Venka-
taraman, Org. Lett. 2001, 3, 4315; d) D. Ma, Q. Cai, H. Zhang,
Org. Lett. 2003, 5, 2453; e) F. Y. Kwong, S. L. Buchwald, Org. Lett.
2003, 5, 793; f) H. Zhang, Q. Cai, D. Ma, J. Org. Chem. 2005, 70,
5164.
2
4
further purified by silica gel chromatography (1:1 hexanes/dichloro-
methane) to yield 1-phenyl-1H-pyrazole (1) as an oil (270 mg, 94%
1
yield). Selected data: H NMR (400 MHz, CDCl ): d = 7.95–7.96 (dd,
3
1
6
1
H), 7.71–7.75 (m, 3H), 7.47–7.50 (m, 2H), 7.28–7.34 (m, 1H), 6.49–
1
3
.50 ppm (dd, 1H); C NMR (100 MHz, CDCl ): d = 141.09, 140.22,
3
29.45, 126.75, 126.46, 119.23, 107.61 ppm; HRMS: m/z calcd for
[6] For recent works dealing with iron-mediated arylations concern-
ing CÀC bond formation, see: a) G. Cahiez, H. Avedissian,
C H N [M+H]: 145.0766; found: 145.0766.
9
8
2
Synthesis 1998, 1199; b) W. Dohle, F. Kopp, G. Cahiez, P. Knochel,
Synlett 2001, 1901; c) A. Fürstner, A. Leitner, M. Mendez, H.
Krause, J. Am. Chem. Soc. 2002, 124, 13856; d) R. B. Bedford,
D. W. Bruce, R. M. Frost, J. W. Goodby, M. Hird, Chem.
Commun. 2004, 2822; e) R. Martin, A. Fürstner, Angew. Chem.
2004, 116, 4045; Angew. Chem. Int. Ed. 2004, 43, 3955; f) M.
Nakamura, K. Matsuo, S. Ito, E. Nakamura, J. Am. Chem. Soc.
Received: August 4, 2006
Published online: December 22, 2006
Keywords: copper · cross-coupling · iron · nitrogen heterocycles
.
2004, 126, 3686; g) E. Shirakawa, T. Yamafumi, T. Kimura, S.
[
1] For reviews, see: a) K. Kunz, U. Scholtz, D. Ganzer, Synlett 2003,
Yamaguchi, T. Hayashi, J. Am. Chem. Soc. 2005, 127, 17164; h) A.
Fürstner, R. Martin, Chem. Lett. 2005, 5, 624; i) A. Fürstner, H.
Krause, C. W. Lehmann, Angew. Chem. 2006, 118, 454; Angew.
Chem. Int. Ed. 2006, 45, 440. For one example of iron-catalyzed
CaliphaticÀN bond formation, see: B. Plietker, Angew. Chem. 2006,
15, 2428 – 2439; b) S. V. Ley, A. W. Thomas, Angew. Chem. 2003,
15, 5558; Angew. Chem. Int. Ed. 2003, 42, 5400. See references
1
cited therein and also references [2a,d,e].
[
2] a) F. Ullmann, Ber. Dtsch. Chem. Ges. 1903, 36, 2382; b) I.
Goldberg, Ber. Dtsch. Chem. Ges. 1906, 39, 1691; c) For a review,
see: M. Schnürch, R. Flasik, A. F. Khan, M. Spina, M. D.
Mihovilovic, P. Stanetty, Eur. J. Org. Chem. 2006, 3283.
118, 6200; Angew. Chem. Int. Ed. 2006, 45, 6053. For a general
review on iron-catalyzed reactions in organic synthesis, see: C.
Bolm, J. Legros, J. Le Paih, L. Zani, Chem. Rev. 2004, 104, 6217.
7] This catalytic system is protected: M. Taillefer, N. Xia, A. Ouali,
US PATENT 60/818,334, 2006. The application field described
also concerns CÀC, CÀO, CÀS, and CÀP bond formation.
[
3] For patents (also concerning CÀC, CÀO, CÀS, and CÀP bond
[
[
formation), see: a) M. Taillefer, H.-J. Cristau, P. P. Cellier, J.-F.
Spindler, FR 0116547, 2001; b) M. Taillefer, H.-J. Cristau, P. P.
Cellier, J.-F. Spindler, WO 03/050885, 2003; M. Taillefer, H.-J.
Cristau, P. P. Cellier, J.-F. Spindler, A. Ouali, WO 03/101966, 2003;
M. Taillefer, H.-J. Cristau, P. P. Cellier, J.-F. Spindler, A. Ouali, US
8] a) E. Shirakawa, T. Yamagami, T. Kimura, S. Yamaguchi, T.
Hayashi, J. Am. Chem. Soc. 2005, 127, 17164, and references cited
therein. b) For an example of Pd/Cu-mediated CÀN coupling, see:
2
36413, 2003.
4] a) M. Taillefer, A. Ouali, B. Renard, J. F. Spindler, Chem. Eur. J.
006, 12, 5301; b) A. Ouali, J. F. Spindler, H. J. Cristau, M.
I. P. Beletskaya, D. V. Davydov, M. Moreno-Manas, Tetrahedron
Lett. 1998, 39, 5617.
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Angew. Chem. Int. Ed. 2007, 46, 934 –936