Magnetic Fe-Ni Alloy Catalyzed Suzuki Cross-Coupling Reactions of Aryl Halides with Phenylboronic Acid

Article abstract of DOI:10.1002/cctc.201200417

Alloy there matey! The inexpensive and readily prepared magnetic Fe-Ni alloy is employed in the Suzuki reactions of aryl halides with phenylboronic acid. The products are obtained in moderate to excellent yields in the absence of a reducing agent. The magnetic nature of the catalyst is beneficial for the separation of the products, but the recyclability of the catalyst is poor, probably as a result of oxidation and leaching.

Full text of DOI:10.1002/cctc.201200417

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DOI: 10.1002/cctc.201200417
Magnetic Fe–Ni Alloy Catalyzed Suzuki Cross-Coupling
Reactions of Aryl Halides with Phenylboronic Acid
[a]
[a]
[a]
[a]
[a, b]
Rongzhao Zhang, Chengxia Miao, Shoufeng Wang, Chungu Xia, and Wei Sun*
The Suzuki coupling reaction is an important method for the
In conjunction with a project on the development of mag-
[
1]
[14–18]
selective construction of biaryls, and this reaction has found
extensive use in the synthesis of natural products, pharmaceut-
netic nanoparticle catalysts,
we attempted to use the
magnetic Fe–Ni alloy as a catalyst for the Suzuki coupling reac-
tion in the absence of a reducing agent. Fortunately, the cou-
pling reaction of aryl halides with phenylboronic acid proceed-
ed smoothly in the presence of the Fe–Ni alloy to provide the
desired products in satisfactory to excellent yields.
[
2]
icals, and advanced materials. Over the past decade, palladi-
um catalysts have been used commonly for Suzuki coupling
[
3,4]
reactions. Considering the high cost of palladium, the use of
much cheaper nickel catalysts has attracted considerable inter-
[
5–7]
est.
Since the first report by Percec in 1995, remarkable ad-
Procedures for the preparation and characterization of the
[17]
vances have been made in the nickel-catalyzed version of the
Fe–Ni alloy were described earlier. The initial experiments
were carried out by testing the protocol and screening the re-
action conditions with 4-iodoanisole and phenylboronic acid
as model substrates (Table 1). Obviously, the Fe–Ni alloy and
ligand were essential for the coupling reaction (Table 1, en-
tries 1–3). Fortunately, 95% yield could be obtained with Cy3P
as the ligand and NaOH as the base at 1208C in 2 mL dioxane
(Table 1, entry 4). It was found that the reaction temperature
had a significant influence on the yields. The yield was reduced
to 90% when the temperature decreased to 1108C (Table 1,
entry 5), and the reaction did not proceed at a temperature of
908C (Table 1, entry 6). Subsequently, solvent effects were also
investigated (Table 1, entries 4, 7–10), and dioxane was found
[
6a]
Suzuki reaction. The most commonly used Ni sources are
II
the phosphine-coordinated nickel(II) halides. However, Ni com-
plexes as precatalysts often need to be combined with a reduc-
0
ing agent such as Zn or BuLi to generate the Ni species in situ
[
8]
to achieve high efficiency of the catalysts. The nickel salts
NiCl and NiCl ·6H O have also been used as precatalysts for
2
2
2
the Suzuki reaction with nitrogen-containing ligands and with-
[
9]
0
out any ligands, respectively. Recently, the Ni -catalyzed
Suzuki coupling reaction with the direct use of Ni(cod) was
2
[
10]
0
demonstrated.
However, such a Ni source is difficult to
handle in practice because of its high air sensitivity and toxici-
ty. A common feature of most reported systems is the involve-
[
5b]
ment of a homogeneous Ni catalyst.
Despite significant
progress towards the use of homogeneous nickel catalysts in
the Suzuki reaction over the past few years, the recovery and
recycling of the homogeneous catalysts and the contamination
of the products by ligands and/or metals have not been ad-
dressed. Therefore, considering the need for large-scale or
even industrial preparation, it remains highly desirable to de-
velop more practical protocols, such as a heterogeneous cata-
lytic system, for the Suzuki reaction. Hyeon et al. synthesized
monodisperse nanoparticles of Ni and NiO with particle sizes
of 2, 5, and 7 nm as catalysts for the Suzuki coupling reac-
Table 1. Screening the conditions for the reaction of 4-iodoanisole with
phenylboronic acid.
[
a]
[b]
Entry
Base
Solvent
Ligand
no
Yield [%]
[
[
c]
c]
1
2
3
4
5
6
7
8
9
NaOH
NaOH
NaOH
NaOH
NaOH
NaOH
NaOH
NaOH
NaOH
NaOH
dioxane
dioxane
dioxane
dioxane
dioxane
dioxane
DMF
0
0
Cy
no
Cy
3
P
trace
95
3
P
[
d]
[
11]
Cy3P
90
tion. Recently, a new heterogeneous catalyst composed of
copper and nickel oxide particles supported within charcoal
[
e]
Cy
Cy
Cy
Cy
3
3
3
3
P
P
P
P
trace
14
12
26
92
[12]
for the Suzuki–Miyaura reaction was developed by Lipshutz.
However, there are few reports on the use of a magnetic heter-
DMA
DMSO
[
13]
10
toluene
dioxane
dioxane
dioxane
dioxane
dioxane
dioxane
dioxane
dioxane
dioxane
dioxane
Cy3P
ogeneous catalyst for the Suzuki coupling reaction.
1
1
K
2
CO
3
Cy
Cy
Cy
Cy
Cy
3
3
3
3
3
P
P
P
P
P
18
12
13
14
15
16
17
18
19
Cs
2
CO
3
trace
trace
31
NR
46
trace
trace
25
[
a] Dr. R. Zhang, Dr. C. Miao, S. Wang, Prof. Dr. C. Xia, Prof. Dr. W. Sun
State Key Laboratory for Oxo Synthesis and Selective Oxidation
Lanzhou Institute of Chemical Physics
Chinese Academy of Sciences
KOtBu
PO
NEt
K
3
4
3
NaOH
NaOH
NaOH
NaOH
NaOH
PPh
3
Lanzhou, 730000 (China)
Fax: (+86)931-827-7088
E-mail: wsun@licp.cas.cn
(C
(C
6
2
H
H
5
O)
O)
3
3
P
P
5
DMEDA
phen
[b] Prof. Dr. W. Sun
20
33
Suzhou Institute of Nano-Tech and Nano-Bionics
Chinese Academy of Sciences
Suzhou, 215123 (China)
[
(
(
a] Reaction conditions: 4-iodoanisole (0.5 mmol), phenylboronic acid
0.75 mmol), catalyst (0.1 mmol), solvent (2 mL), base (1.0 mmol), ligand
0.1 mmol), T=1208C, t=12 h. [b] Isolated yield. [c] No catalyst. [d] T=
Supporting information for this article is available on the WWW under
http://dx.doi.org/10.1002/cctc.201200417.
1
10 8C. [e] T=908C.
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to be the best solvent (Table 1, entry 4). Additionally, the
nature of the base was examined, and the results revealed that
NaOH is a better base than the others (Table 1, entries 11–15).
Then, other ligands, such as PPh , (C H O) P, (C H O) P, DMEDA
mized conditions (Table 2, entry 7), and this phenomenon may
be ascribed to the formation of a stable (nitroso)nickel(II) spe-
[19,20]
cies.
Additionally, a series of aryl bromides were investigat-
ed in the reaction with phenylboronic acid. The reactivities of
bromobenzenes with electron-donating groups in the para po-
sitions were lower than those of substituted iodobenzenes
(Table 2, entries 8 and 9), and 1-bromo-2-methoxybenzene ex-
hibited similar reactivity to provide the product in moderate
yield (Table 2, entry 10). Moreover, the reaction of 1-chloro-4-
methylbenzene with phenylboronic acid afforded the desired
product in only 35% yield (Table 2, entry 11).
3
6
5
3
2
5
3
(
N,N’-dimethylethylenediamine), and phen (phenanthroline),
were tested in the presence of NaOH; however, no improve-
ment was observed (Table 1, entries 16–20). Therefore, the op-
timized reaction conditions were NaOH as the base, dioxane as
the solvent, and Cy P as the ligand at 1208C for 12 h.
3
Having established the effective catalytic system for the cou-
pling reaction, we further explored the utility and generality of
this approach for the reaction of a variety of aryl halides with
phenylboronic acid under the optimized conditions. Fortunate-
ly, aryl iodides with electron-donating groups in the para posi-
tions reacted smoothly with phenylboronic acid to afford the
desired products in good yields (Table 2, entries 1–3). ortho-
Substituted iodobenzenes including 2-iodoanisole, 2-iodoto-
luene, and 1-iodonaphthalene showed low reactivity, and the
products were obtained only in moderate yields, probably as
a result of steric hindrance (Table 2, entries 4–6). However, io-
dobenzene with electron-withdrawing substituent such as
nitro group or trifluoromethyl did not work under the opti-
An appealing feature of this magnetic Fe–Ni alloy catalyzed
Suzuki coupling reaction would be the facile separation of the
[21]
catalyst from the reaction mixture. Magnetic separation is an
attractive alternative to filtration or centrifugation, as it pre-
vents loss of the catalyst and increases the reusability of the
catalyst. Therefore, we carried out the reactions by using 4-io-
doanisole and phenylboronic acid as model substrates to test
the recyclability of the Fe–Ni alloy (Figure 1). After the first run,
the product was collected with a syringe, whereas the catalyst
[
a]
Table 2. Fe–Ni alloy catalyzed Suzuki coupling reactions.
[
b]
Entry
Aryl halide
Product
Yield [%]
1
2
3
95
93
91
Figure 1. Recyclability of the Fe–Ni alloy in the reaction of 4-iodoanisole
with phenylboronic acid.
4
5
64
62
was recovered in the reactor by using a permanent magnet.
Then, the recovered catalyst was washed with ethanol and dis-
tilled water inside the reactor and dried under vacuum. Finally,
the catalyst was reused in successive Suzuki reactions by
adding new portions of solvent, base, and substrate. Unfortu-
nately, the reused Fe–Ni catalyst gave the product in only 47%
yield. After the third run, the yield of the product was only
6
60
7
8
9
0
0
1
1%. Then, we tested the leaching level of the reaction mix-
ture, and the weight loss of the catalyst was 5.15 and
.67 ppm for Fe and Ni, respectively. In addition, the reaction
was inert in the presence of Zn or nBuLi (4 equiv.; Scheme 1),
83
87
0
10
II
0 [8]
which were previously reported to transform Ni into Ni . This
phenomenon indicated that the leached Ni has no activity in
11
69
35
0
the reaction. Therefore, we presume that Ni at the surface of
[11]
the Fe–Ni alloy was significantly oxidized and that the cata-
lyst was partially destroyed under the strong basic and high
temperature conditions, which would result in catalyst
leaching.
12
[
(
(
a] Reaction conditions: aryl halide (0.5 mmol), phenylboronic acid
0.75 mmol), catalyst (0.1 mmol), dioxane (2 mL), NaOH (1.0 mmol), Cy P
3
0.1 mmol), T=1208C, t=12 h. [b] Isolated yield.
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Acknowledgements
This work was supported by the National Natural Science Foun-
dation of China (21073210 and 21133011).
Keywords: iron · nickel · alloys · magnetic properties · biaryls ·
cross-coupling
Scheme 1. Activity of the reused Fe–Ni alloy in the presence of Zn or nBuLi.
[
1] a) N. Miyaura, A. Suzuki, Chem. Rev. 1995, 95, 2457–2483; b) J. Hassan,
M. Sevignon, C. Gozzi, E. Schulz, M. Lemaire, Chem. Rev. 2002, 102,
In summary, an inexpensive and readily prepared magnetic
Fe–Ni alloy catalyst exhibited excellent activity in the Suzuki
coupling reaction of aryl halides and phenylboronic acid with-
out the addition of a reducing agent. Interestingly, the mag-
netic nature of the catalyst allowed easy separation of the
product and the catalyst from the reaction mixture. Unfortu-
nately, the efficiency of the catalyst decreased markedly after
1
359–1469; c) N. Miyaura, Top. Curr. Chem. 2002, 219, 11–59.
[2] a) L. Pu, Chem. Rev. 1998, 98, 2405–2494; b) K. C. Nicolaou, C. N. C.
Boddy, S. Brase, N. Winssinger, Angew. Chem. 1999, 111, 2230–2287;
Angew. Chem. Int. Ed. 1999, 38, 2096–2152; c) O. Baudoin, M. Cesario,
D. Guenard, F. Gueritte, J. Org. Chem. 2002, 67, 1199–1207.
3] a) S. P. Stanforth, Tetrahedron 1998, 54, 263–303; b) A. Suzuki, J. Orga-
nomet. Chem. 1999, 576, 147–168; c) S. Kotha, K. Lahiri, D. Kashinath,
Tetrahedron 2002, 58, 9633–9695; d) F. Bellina, A. Carpita, R. Rossi, Syn-
thesis 2004, 15, 2419–2440; e) L. Yin, J. Liebscher, Chem. Rev. 2007, 107,
[
0
the second run, probably as a result of the oxidation of Ni at
1
1
33–173; f) R. Martin, S. L. Buchwald, Acc. Chem. Res. 2008, 41, 1461–
473; g) G. C. Fu, Acc. Chem. Res. 2008, 41, 1555–1564.
the surface of the Fe–Ni alloy and of partial destruction of the
catalyst under the strong basic and high temperature condi-
tions, which would lead to leaching. Investigation of the de-
tailed mechanism for this Suzuki reaction catalyzed by the Fe–
Ni alloy and application of the magnetic Fe–Ni alloy to other
reactions are in progress.
[4] a) D. W. Old, J. P. Wolfe, S. L. Buchwald, J. Am. Chem. Soc. 1998, 120,
9
3
722–9723; b) A. F. Littke, G. C. Fu, Angew. Chem. 1998, 110, 3586–
587; Angew. Chem. Int. Ed. 1998, 37, 3387–3388; c) J. P. Wolfe, R. A.
Singer, B. H. Yang, S. L. Buchwald, J. Am. Chem. Soc. 1999, 121, 9550–
561; d) X. Bei, T. Crevier, A. S. Guran, B. Jandeleit, T. S. Powers, H. W.
9
Turner, T. Uno, W. H. Weinberg, Tetrahedron Lett. 1999, 40, 3855–3858;
e) C. M. Zhang, J. K. Huang, M. L. Trudell, S. P. Nolan, J. Org. Chem. 1999,
6
1
4, 3804–3805; f) A. F. Littke, C. Dai, G. C. Fu, J. Am. Chem. Soc. 2000,
22, 4020–4028; g) D. Zim, A. S. Gruber, G. Ebeling, J. Dupont, A. L.
Experimental Section
Monteiro, Org. Lett. 2000, 2, 2881–2884; h) M. C. Willis, L. Mori, K. Yama-
guchi, T. Hara, T. Mizugaki, K. Ebitani, K. Kaneda, J. Am. Chem. Soc. 2002,
General
1
24, 11572–11573; i) G. Altenhoff, R. Goddard, C. W. Lehmann, F. Glorius,
Angew. Chem. 2003, 115, 3818–3821; Angew. Chem. Int. Ed. 2003, 42,
690–3693; j) S. D. Walker, T. E. Barder, J. R. Martinelli, S. L. Buchwald,
The pure products were isolated by column chromatography,
which was generally performed on silica gel (200–300 mesh). TLC
inspections were performed on silica gel GF254 plates. The products
were characterized by HP 6890/5973 GC–MS and NMR spectrosco-
3
Angew. Chem. 2004, 116, 1907–1912; Angew. Chem. Int. Ed. 2004, 43,
1871–1876; k) G. Altenhoff, R. Goddard, C. W. Lehmann, F. Glorius, J.
Am. Chem. Soc. 2004, 126, 15195–15201; l) H. Lebel, M. K. Janes, A. B.
Charette, S. P. Nolan, J. Am. Chem. Soc. 2004, 126, 5046–5047; m) T. E.
Barder, S. D. Walker, J. R. Martinelli, S. L. Buchwald, J. Am. Chem. Soc.
1
13
py. H NMR and C NMR spectra were recorded with a Bruker
Avance III 400 MHz spectrometer in CDCl3.
2
2
005, 127, 4685–4696; n) K. W. Anderson, S. L. Buchwald, Angew. Chem.
005, 117, 6329–6333; Angew. Chem. Int. Ed. 2005, 44, 6173–6177.
[
5] a) A. F. Indolese, Tetrahedron Lett. 1997, 38, 3513–3516; b) B. H. Lip-
shutz, J. A. Sclafani, P. A. Blomgren, Tetrahedron 2000, 56, 2139–2144;
c) K. Inada, N. Miyaura, Tetrahedron 2000, 56, 8657–8660; d) Z.-Y. Tang,
Q.-S. Hu, J. Org. Chem. 2006, 71, 2167–2169.
General procedure for the Suzuki reaction catalyzed by the
Fe–Ni alloy
A sealed tube was charged with aryl halide (0.5 mmol), Fe–Ni
[6] a) V. Percec, J.-Y. Bae, D. H. Hill, J. Org. Chem. 1995, 60, 1060–1065; b) D.
Zim, V. R. Lando, J. Dupont, A. L. Monterio, Org. Lett. 2001, 3, 3049–
(
0.1 mmol), Cy P (28.0 mg, 0.1 mmol), NaOH (40.0 mg, 1.0 mmol),
3
3
2
051; c) V. Percec, G. M. Golding, J. Smidrkal, O. Weichold, J. Org. Chem.
004, 69, 3447–3452; d) J.-I. Kuroda, K. Inamoto, K. Hiroya, T. Doi, Eur. J.
Org. Chem. 2009, 2251–2261; e) X.-H. Fan, L.-M. Yang, Eur. J. Org. Chem.
010, 2457–2460; f) T. Tu, H. Mao, C. Herbert, M. Xu, H. Dçtz, Chem.
and dioxane (2 mL) under an argon atmosphere. The reaction mix-
ture was stirred at 1208C for 12 h. The product was washed with
water, extracted with ethyl acetate, and dried with Na SO . After
2
4
2
purification by silica gel chromatography, the biaryl product was
Commun. 2010, 46, 7796–7798.
7] a) M. Tobisu, T. Shimasaki, N. Chatani, Angew. Chem. 2008, 120, 4944–
1
13
characterized by H NMR and C NMR spectroscopy.
[
4947; Angew. Chem. Int. Ed. 2008, 47, 4866–4869; b) B.-T. Guan, Y.
Wang, B.-J. Li, D.-G. Yu, Z.-J. Shi, J. Am. Chem. Soc. 2008, 130, 14468–
1
4470; c) K. W. Quasdorf, X. Tian, N. K. Garg, J. Am. Chem. Soc. 2008,
Recycling experiments
1
30, 14422–14423; d) K. W. Quasdorf, M. Riener, K. V. Petrova, N. K.
Garg, J. Am. Chem. Soc. 2009, 131, 17748–17749; e) A. Antoft-Finch, T.
Blackburn, V. Snieckus, J. Am. Chem. Soc. 2009, 131, 17750–17752; f) Y.-
L. Zhao, Y. Li, Y. Li, L.-X. Gao, F.-S. Han, Chem. Eur. J. 2010, 16, 4991–
A mixture of 4-iodoanisole (117.0 mg, 0.5 mmol), phenylboronic
acid (91.4 mg, 0.75 mmol), Fe–Ni (0.1 mmol), NaOH (40.0 mg,
1
1
.0 mmol), and dioxane (2 mL) in a sealed tube was heated at
208C under an argon atmosphere for 12 h. The cooled mixture
4994.
[
8] a) S. Saito, M. Sakai, N. Miyaura, Tetrahedron Lett. 1996, 37, 2993–2996;
b) J.-C. Galland, M. Savignac, J.-P. GenÞt, Tetrahedron Lett. 1999, 40,
was purified by silica gel chromatography. The catalyst was recov-
ered by using an external magnet, washed with distilled water (5ꢁ
2323–2326.
3
mL) and ethyl acetate (5ꢁ3 mL), dried under reduced pressure,
[9] a) N. E. Leadbeater, S. M. Resouly, Tetrahedron 1999, 55, 11889–11894;
b) D. Zim, A. L. Monteiro, Tetrahedron Lett. 2002, 43, 4009–4011.
and reused directly in the next cycle.
ꢀ
2013 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
ChemCatChem 2013, 5, 142 – 145 144

CHEMCATCHEM
COMMUNICATIONS
www.chemcatchem.org
[10] a) Z.-Y. Tang, Q.-S. Hu, J. Am. Chem. Soc. 2004, 126, 3058–3059; b) Z.-Y.
Tang, S. Spinella, Q.-S. Hu, Tetrahedron Lett. 2006, 47, 2427–2430.
[16] R. Z. Zhang, J. M. Liu, S. F. Wang, J. Z. Niu, C. G. Xia, W. Sun, ChemCatCh-
em 2011, 3, 146–149.
[
11] J. Park, E. Kang, S. U. Son, H. M. Park, M. K. Lee, J. Kim, K. W. Kim, H.-J.
Noh, J.-H. Park, C. J. Bae, J.-G. Park, T. Hyeon, Adv. Mater. 2005, 17, 429–
[17] a) R. Z. Zhang, C. X. Miao, S. F. Wang, C. G. Xia, W. Sun, ChemCatChem
2012, 4, 192–195; b) G. C. Hoffmann, Am. J. Sci. 1905, 19, 319–320.
[18] R. Z. Zhang, C. X. Miao, Z. Q. Shen, S. F. Wang, C. G. Xia, W. Sun, Chem-
CatChem 2012, 4, 824–830.
434.
ˇ
ˇ
´
[
[
[
[
12] B. H. Lipshutz, D. M. Nihan, E. Vinogradova, B. R. Taft, Z. V. Boskovic, Org.
[
[
[
19] R. S. Berman, J. K. Kochi, Inorg. Chem. 1980, 19, 248–254.
20] S. Saito, S. Ohtani, N. Miyaura, J. Org. Chem. 1997, 62, 8024–8030.
21] S. Shylesh, V. Schꢂnemann, W. R. Thiel, Angew. Chem. 2010, 122, 3504–
Lett. 2008, 10, 4279–4282.
13] Y. Wu, D. Wang, P. Zhao, Z. Niu, Q. Peng, Y. Li, Inorg. Chem. 2011, 50,
2
046–2048.
14] J. M. Liu, X. G. Peng, W. Sun, Y. W. Zhao, C. G. Xia, Org. Lett. 2008, 10,
933–3936.
15] R. Z. Zhang, J. M. Liu, F. W. Li, S. F. Wang, C. G. Xia, W. Sun, Chin. J. Chem.
011, 29, 525–530.
3537; Angew. Chem. Int. Ed. 2010, 49, 3428–3459.
3
Received: June 27, 2012
Published online on November 22, 2012
2
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