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Synlett 2011(2): 268-272  
DOI: 10.1055/s-0030-1259291
LETTER
© Georg Thieme Verlag Stuttgart ˙ New York

Efficient Iron/Copper-Cocatalyzed O-Arylation of Phenols with Bromoarenes

Xiaoyan Liu, Songlin Zhang*
Key Laboratory of Organic Synthesis of Jiangsu Province, College of Chemistry, Chemical Engineering and Materials Science,, Suzhou University, Dushu Lake Campus, Suzhou, 215123, P. R. of China
Fax: +86(512)65880352; e-Mail: zhangsl@suda.edu.cn;
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Publication History

Received 2 October 2010
Publication Date:
23 December 2010 (online)

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Abstract

Low catalytic amount CuI and Fe(acac)3 were found to effectively promote the C-O cross-coupling reaction in the presence of K2CO3 as the base. A serious of diaryl ethers with different substitutents can be synthesized in good to excellent yields. This efficient and economic method is attractive for applications on an industrial scale.

Key words

catalysis - iron - copper - diaryl ether

    Primary data for this article are available online and can be cited using the following DOI: 10.4125/pd0008th:
  • Primary Data
    • FIDs and associated files for the ¹H and ¹³C NMR spectra for compounds 1-4 are summarized.
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General Procedure for the Synthesis of Diaryl Ethers
A Schlenk tube equipped with a magnetic stir bar was charged with K2CO3 (138 mg, 1 mmol), Fe(acac)3 (3.5 mg, 2% mol), CuI (1.0 mg, 1% mol), and the phenol (0.5 mmol) in anhyd DMF (0.8 mL). The reaction mixture was heated at 135 ˚C. After being stirred at this temperature for 12 h, the mixture was cooled to r.t. and diluted with Et2O. The resulting suspension was directly filtered through a pad of Celite, and the filtrate was washed with sat. NaCl and dried over anhyd Na2SO4. The organic phase was concentrated, and the crude mixtures were purified by column chroma-tography on silica gel (300-400 mesh) using PE-EtOAc solvent mixture as the eluent. Diphenyl Ether (3a)
¹H NMR (400 MHz, CDCl3): δ = 7.33 (t, J = 7.6 Hz, 4 H), 7.10 (t, J = 7.2 Hz, 2 H), 7.01 (d, J = 7.8 Hz, 4 H). ¹³C NMR (100 MHz, CDCl3): δ = 157.70, 130.19, 123.70, 119.34.
N -(4-Phenoxyphenyl)acetamide (Table 2, Entry 6) ¹H NMR (400 MHz, CDCl3): δ = 7.45 (d, J = 8.8 Hz, 2 H), 7.42 (s, 1 H), 7.31 (t, J = 7.8 Hz, 2 H), 7.08 (t, J = 7.4 Hz, 1 H), 6.97 (d, J = 7.8 Hz, 4 H), 2.17 (s, 3 H). ¹³C NMR (100 MHz, CDCl3): δ = 169.25, 157.87, 153.82, 133.90, 130.15, 123.51, 122.29, 119.92, 118.82, 24.71.
1- tert -Butyl-2-phenoxybenzene (Table 2, Entry 8) ¹H NMR (400 MHz, CDCl3): δ = 7.42 (d, J = 7.7 Hz, 1 H), 7.33 (t, J = 7.8 Hz, 2 H), 7.15 (t, J = 7.0 Hz, 1 H), 7.10-7.05 (m, 2 H), 6.99 (d, J = 8.0 Hz, 2 H), 6.84 (d, J = 7.9 Hz, 1 H), 1.44 (s, 9 H). ¹³C NMR (100 MHz, CDCl3): δ = 158.24, 156.30, 141.40, 130.13, 127.67, 127.57, 123.68, 123.08, 120.65, 119.13, 35.24, 30.62.
4-(4-Methoxyphenoxy)aniline (Table 2, Entry 15) ¹H NMR (400 MHz, CDCl3): δ = 6.90 (d, J = 8.8 Hz, 2 H), 6.84-6.81 (m, 4 H), 6.65 (d, J = 8.4 Hz, 2 H) 3.78 (s, 3 H). ¹³C NMR (100 MHz, CDCl3): δ = 155.43, 152.46, 150.46, 142.47, 120.37, 119.49, 116.66, 115.08, 56.09
3-(4-Methoxyphenoxy)pyridine (Table 2, Entry 23) ¹H NMR (400 MHz, CDCl3): 8.19 (d, J = 4.9 Hz, 1 H,) 7.66 (t, J = 7.7 Hz, 1 H), 7.08 (d, J = 9.1 Hz, 2 H), 6.97 (d, J = 6.0 Hz, 1 H), 6.93 (d, J = 9.1 Hz, 2 H), 6.86 (s, 1 H), 3.82 (s, 3 H).¹³C NMR (100 MHz, CDCl3): 164.64, 156.93, 148.08, 147.73, 139.69, 122.77, 118.47, 115.14, 111.42, 55.95.