Synthesis and Characterization of Polymer Anchored Cu(II) Complexes
1
of the products were carried out by H NMR spectros-
ides. The reactions are, in general, more efficient with
respect to quantity of catalyst required and the yields
obtained and a much wider range of substrates can be
utilized including electron-rich, electron-deficient and
electronically neutral aryl halides and phenols. The mild
base cesium carbonate is effective in a large majority of
these reactions and low polar solvent ACN is used as a
solvent. We are currently working to improve the scope
and generality of copper-catalyzed diaryl ether forma-
tion. We anticipate that existing difficulties with homo-
geneous catalyst will be overcome through the devel-
opment of new polymer anchored Cu(II) Schiff base
catalyst systems.
In summary, we have developed a cheap and simple
way to carry out the Ullmann diaryl ether synthesis,
which is applicable to a wide variety of substrates with
different functional groups. The application of this
method to the synthesis of more complex diaryl ethers,
as well as mechanism studies, is in progress. We have
developed a new polymer anchored Cu(II) Schiff base
catalyst which can be successfully applied in a number
of cross-coupling reactions and gives better results than
other reported copper catalysts. The polymer anchored
Cu(II) Schiff base catalyst can be recycled with minimal
loss of activity and it is able to promote the reaction
catalytically. The easy workup procedure provides a
method that is well suited toward the synthesis of
parallel libraries based upon this type of transformation.
copy using Bruker DPX-400 in CDCl3 with TMS as
internal standard. Chemical shifts were given as δ value
with reference to tetramethylsilane (TMS) as the inter-
nal standard. The reaction products were quantified (GC
data) using a Varian 3400 gas chromatograph equipped
with a 30 m CP-SIL8CB capillary column and a flame
ionization detector and identified (GC-MS) by Trace
DSQ II GC-MS equipped with a 60 m TR-50MS capil-
lary column. Standardized of the products were done by
calibration using dihexyl ether as internal standard.
Color, m.p. and H and 13C NMR data of all the prod-
1
ucts are given below:
Diphenylether34 (a): colorless liquid; 1H NMR
(CDCl3, 400 MHz) δ: 7.09—7.15 (m, 4H), 7.16—7.22
(m, 2H); 7.39—7.46 (m, 4H); 13C NMR (CDCl3, 100
MHz) δ: 119, 123.4, 129.9, 157.4.
4-Methoxy-diphenylether35 (b): Colorless liquid;
1H NMR (CDCl3, 400 MHz) δ: 3.73 (s, 3H), 6.78—6.82
(m, 2H), 6.85—6.92 (m, 4H), 6.93—6.98 (m, 1H),
7.16—7.24 (m, 2H); 13CNMR (CDCl3, 100 MHz) δ:
55.8, 115, 117.8, 121, 122.6, 129.7, 150.3, 156.1, 158.7.
4-Methyl-diphenylether34 (c): Colorless liquid;
1H NMR (400 MHz, CDCl3) δ: 2.42 (s, 3H), 7.01 (d,
J=8.0 Hz, 2H), 7.05—7.1 (m, 2H), 7.12—7.18 (m, 1H),
7.21 (d, J=8.4 Hz, 2H), 7.38 (t, J=8.4 Hz, 2H); 13C
NMR (CDCl3, 100 MHz) δ: 20.8, 118.5, 119.3,122.9,
129.8, 130.4, 133.0, 154.9, 157.9.
1-Methyl-diphenylether34 (d): Colorless liquid;
1H NMR (CDCl3, 400 MHz) δ: 2.23 (s, 3H), 6.87—6.92
(m, 3H), 6.98—7.08 (m, 2H), 7.12—7.18 (m, 1H),
7.22—7.31 (m, 3H); 13CNMR (CDCl3, 100 MHz) δ:
16.3, 117.4, 119.9, 122.4, 124.1, 127.3, 129.8, 130.1,
131.6, 154.6, 158.1.
Acknowledgements
We thank the Department of Chemistry, University
of Calcutta, for providing us the instrumental support.
We gratefully acknowledge DST, New Delhi, for award
of grant under its FIST program to the Department of
Chemistry, University of Kalyani. SMI acknowledge the
following agencies for funding: DST, CSIR and UGC,
New Delhi, India.
4-Chloro-diphenylether36 (e): Colorless liquid;
1H NMR (CDCl3, 400 MHz) δ: 6.82—6.87 (m, 2H),
6.89—6.93 (m, 2H), 7.01—7.06 (m, 1H), 7.15—7.21
(m, 2H), 7.22—7.28 (m, 2H); 13C NMR (CDCl3, 100
MHz) δ: 119.1, 120.2, 123.8, 128.3, 129.8, 130, 156.1,
157.
References
4-Nitro-diphenylether36 (f): Yellow solid; m.p. 57—
1
Pellón, R. F.; Carrasco, R.; Milián, V.; Rodes, L. Synth.
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Theil, F. Angew. Chem., Int. Ed. 1999, 38, 2345.
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60 ℃ (Lit.36 60 ℃); H NMR (CDCl3, 400 MHz) δ:
1
6.99—7.02 (m, 2H), 7.05—7.10 (m, 2H), 7.22—7.29
(m, 1H), 7.40—7.44 (m, 2H), 8.16—8.21 (m, 2H);
13C NMR (CDCl3, 100 MHz) δ: 117.2, 120.6, 125.5,
126,130.4, 142.7, 154.8, 163.4.
2
3
4-Acetyl-diphenylether36 (g): White solid; m.p. 47
4
(a) Mann, G.; Hartwig, J. F. J. Am. Chem. Soc. 1996, 118,
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℃ (Lit.36 49—51 ℃); H NMR (CDCl3, 400 MHz) δ:
1
7.94 (d, J=10.4 Hz, 2H), 7.39 (m, 2H), 7.20 (t, J=7.2
Hz, S10 1H), 7.07 (d, J=7.8 Hz, 2H), 7.00 (d, J=9.0
Hz, 2H), 2.57 (s, 3H); 13C NMR (CDCl3, 100 MHz) δ:
196.7, 161.9, 155.5, 131.9, 130.6, 130.0, 124.6, 120.2,
117.3, 26.4.
(b) Hartwig, J. F. Acc. Chem. Res. 1998, 31, 852.
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5
6
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Conclusion
The current procedure enhances the utility of copper
catalyzed coupling reactions of phenols with aryl hal-
For some exemples of Cu catalyzed coupling of aryl halides
Chin. J. Chem. 2010, 28, 1810— 1820
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