Nano CoCuFe2O4-catalyzed coupling reaction of arylboronic acid with amines and thiols: An atom-economic and ligand-free route to access unsymmetrical amines and sulfides

Article abstract of DOI:10.1002/aoc.4568

An efficient protocol was developed for the nano CoCuFe₂O₄-catalyzed C-N and C-S bond formation. By this catalytic system, both amine and sulfide-based structural motifs were formed efficiently in aryl halide-free route. The amination reaction of phenyl boronic acid with various types of amines was conducted under ligand-free conditions, in ethanol as a green solvent at 60°C. Unsymmetrical diaryl/aryl alkyl sulfide synthesis via the coupling reaction of arylboronic acids with thiols was also conducted. The nano cobalt-copper ferrite was used as a heterogenous efficient, inexpensive, magnetically separable and recyclable catalyst that can be used for several cycles.

Full text of DOI:10.1002/aoc.4568

Received: 23 March 2018
DOI: 10.1002/aoc.4568
Revised: 6 May 2018
Accepted: 22 May 2018
F U L L P A P E R
Nano CoCuFe O ‐catalyzed coupling reaction of arylboronic
2
4
acid with amines and thiols: An atom‐economic and ligand‐
free route to access unsymmetrical amines and sulfides
Firouz Matloubi Moghaddam
| Raheleh Pourkaveh | Milad Gholamtajari
Laboratory of Organic Synthesis and
Natural Products, Department of
Chemistry, Sharif University of
Technology, Azadi Street, PO Box
An efficient protocol was developed for the nano CoCuFe O ‐catalyzed C‐N
2
4
and C‐S bond formation. By this catalytic system, both amine and sulfide‐based
structural motifs were formed efficiently in aryl halide‐free route. The
amination reaction of phenyl boronic acid with various types of amines was
conducted under ligand‐free conditions, in ethanol as a green solvent at
111559516, Tehran, Iran
Correspondence
Firouz Matloubi Moghaddam, Laboratory
of Organic Synthesis and Natural
Products, Department of Chemistry,
Sharif University of Technology, Azadi
Street, PO Box 111559516 Tehran, Iran.
Email: matloubi@sharif.edu
60°C. Unsymmetrical diaryl/aryl alkyl sulfide synthesis via the coupling
reaction of arylboronic acids with thiols was also conducted. The nano
cobalt‐copper ferrite was used as a heterogenous efficient, inexpensive, mag-
netically separable and recyclable catalyst that can be used for several cycles.
KEYWORDS
2 4
amination, boronic acid, CoCuFe O , ligand‐free, sulfidation
[
9]
[10]
[11]
1
| INTRODUCTION
copper, iron,
cobalt
and also metal‐free cross‐
coupling catalysis. Also, employing homogeneous
catalysts in those processes makes them inefficient in
pharmaceutical synthesis and drug discovery approaches
as a trace amount of remaining metal in products has
The carbon−heteroatom bond forming reaction is one of
the most important reactions in organic synthesis, phar-
[
1]
maceutical, dye, agrochemical and biomolecules.
[
12]
Therefore, improvement of efficient methodologies for
generating carbon−heteroatom bonds received consider-
able attention.
negative effects on health.
Concerning facile catalyst recycling, magnetic cata-
lysts rank among the available techniques, as in this
way the application of an external magnet readily sepa-
rates the catalyst from the reaction media and eliminates
the need for filtration.
The first metal‐based synthesis of amines was
reported by Ullmann and Goldberg over 100 years
[2,3]
ago.
In 1983, Migita and his co‐workers synthesized
aniline derivatives via tributyltin amide and aryl bro-
mides catalyzed with palladium and phosphine ligand.
Then, in the 2000s, Buchwald and Hartwig used palla-
dium and copper complexes to activate aryl halides to
generate C‐N bond in the presence of amine as a nucleo-
Recently, in the realm of cross‐coupling reactions,
magnetic metal oxide nanoparticles with spinel structure
[
4]
[
13]
have attracted considerable attention.
In fact, the syn-
ergetic effect among existing transition metals in these
[
14,15]
systems could enhance their catalytic activity.
[
5,6]
phile.
tion conditions, such as requiring a high temperature
110°C), which makes them incompatible for a range of
functional groups. The high cost and toxicity of palladium
However, these methods suffer from harsh reac-
It is worth noting that transition metal‐free amination
reaction was also carried out, but the rates of conversions
and selectivity were not as high as metal‐catalyzed
(
[
16]
ones.
[7]
complexes have stimulated the search for alternative
affordable transition metal catalysts, such as nickel,
In the case of thioether synthesis, the strong coordina-
tive feature of sulfur‐containing compounds leads to
[
8]
Appl Organometal Chem. 2018;e4568.
wileyonlinelibrary.com/journal/aoc
© 2018 John Wiley & Sons, Ltd.
1 of 8
https://doi.org/10.1002/aoc.4568

2
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MOGHADDAM ET AL.
some difficulties in C‐S bond formation as sulfur species
rapidly and irreversibly deactivate the catalyst. The
Chan–Lam reaction is a valuable alternative to traditional
cross‐coupling for construction of carbon‐heteroatom
bonds due to the mildness of this reaction. The first C‐S
bond formation through the Chan–Lam reaction was
reported by Guy et al., in which boronic acids reacted
with alkyl thiols in the presence of stoichiometric Cu
shown in Figure S2, the O 1s XPS signals showed three
peaks at 529.8, 531.7 and 533.8 eV. The main peak at
529.8 eV is attributed to the contribution of the crystal lat-
tice oxygen, which is a characteristic of the surface spinel.
However, the appearance of shoulder peaks at higher
binding energy is not clear. In fact, the exact assignment
of them is rather complex due to a number of factors,
such as surface defects, contaminants, impurities or
chemisorbed oxygen species.
[17]
(OAc)2.
Numerous modifications of this method have been
Concerning the Fe 2p spectra, in Figure S3 one can
see the binding energy at 709.8 eV is ascribed to Fe ions
[18,19]
3+
published thereafter.
However, the development of
mild and cost‐effective catalytic procedures for N‐
arylation of amines and S‐arylation of thiols still remains
an active research area. Aryl halide, aryllead, arylbismuth,
arylborane and arylsilane compounds are used as coupling
in octahedral sites, while the binding energy at 713.2 eV
3+
is caused by Fe ions in tetrahedral sites.
2+
The cobalt cations are present as Co cations. The
existence of two peaks with binding energies of 779.8
and 781.4 eV arises from the random distribution of the
[20–24]
components for arylation reactions.
Of these aryl
2+
surrogates, arylboronates are commercially available,
non‐toxic, easily handled, and stable under air and
moisture.
Co within the tetrahedral and octahedral layers of the
ferrite structure, respectively (Figure 1).
For copper, the XPS analysis revealed that copper
species with 2+ valance are present at the surface of the
In this direction, we wish to report an inexpensive
strategy for amination and sulfidation coupling reactions.
Co and Cu are abundant, inexpensive and a variety of
their salts are commercially available. Using our catalytic
system, the reaction conditions can be improved and
it accelerates the reaction without using expensive
transition metals and ligands such as palladium and
phosphine, respectively.
2+
catalyst. Cu was found to occupy both the tetrahedral
and octahedral sites in spinel. However, the octahedrally
coordinated surface Cu species is predominant. The peak
2+
at 932.8 eV is attributed to octahedral Cu , and the peak
2+
at 934.8 eV to tetrahedral Cu . Satellite signals located
on the higher binding energies (937.3, 940.4, 943.5,
945.3 eV) are sensitive to changes in the coordination
2+
environment of Cu ions (Figure 2).
Binding energies and transitions of Cu 2P3/2, Co 2P3/
and Fe 2P3/2 are summarized in Table S1; assignments
2
2
| RESULTS AND DISCUSSION
.1 | Catalyst synthesis
2
were made by comparison with the values reported in
[
26,27]
the literature.
Apart from previously reported
CoCuFe O4 nanoparticles were prepared using the
analyses, such as atomic absorption spectroscopy,
2
co‐precipitation method according to our previously
[
25]
reported procedure.
We have recently applied
[
25]
CoCuFe O4 in the Sonogashira coupling reaction.
2
Encouraged by the good performance of cobalt‐copper
ferrite on C‐C bond formation, we investigated its appli-
cation in C‐heteroatom bond formation via the Chan–
Lam coupling reaction. Apart from the previously
reported analysis for the characterization of our catalyst,
the exact characterization of heterogeneous catalysts
and a better understanding of factors affecting catalytic
properties are not so simple. By means of X‐ray photo-
electron spectroscopy (XPS) analysis as a surface‐sensitive
technique, we are able to partly overcome this challenge.
Therefore, we determined the cation distribution and
chemical state of the surface of our samples by XPS anal-
ysis. A wide scan of the samples was first realized (0–1200
eV) to detect all the species in the sample (Figure S1). The
XPS spectrum of CoCuFe O possesses four peaks cen-
2
4
tered at 529.8, 709.8, 779.8 and 932.8 eV, corresponding
FIGURE 1 X‐ray photoelectron spectroscopy (XPS) spectrum for
Co 2p of CoCuFe O
2 4
[26,27]
to O 1s, Fe 2p, Co 2p and Cu 2p, respectively.
As

MOGHADDAM ET AL.
3 of 8
reducing atom and step economy, were left behind. Com-
pared with conventional approaches, this method is more
atom‐economic because of using a sub‐stoichiometric
amount of catalyst, whereas in the conventional methods
large quantities of residues such as halide salt are produced
[30]
and a large amount of transition metal source is wasted.
2.2 | Catalytic activity
Our study initially focused on a typical reaction of
phenyboronic acid and aniline as model substrates. Ini-
tially, the results of base screening showed the desired
product could be obtained in both organic and inorganic
bases. However, the high yield of the product was isolated
in the presence of KOH, and other bases such as K CO ,
2
3
KOAc, KOtBu, NaHCO , DABCO and Et N were not
3
3
effective (Table 1, entry 4). Next, we examined the impact
of solvent on amination reactions. After a survey of
several solvents, we found that EtOH was an excellent
solvent for this transformation, which paves the way to
the green chemistry. Strong polar solvents such as DMF
and DMSO were also used resulting in obtaining the
desired product in 80% and 30% yields, respectively.
Reducing the catalyst loading resulted in a decreased
yield of the product. No anticipated product was observed
in the absence of catalyst (Table 1, entry 20). Exploring
the effect of temperature on the reaction showed that
low yields were obtained when the temperature was
changed to room temperature or 40°C, and 60°C was
chosen as an optimum reaction temperature.
FIGURE 2 X‐ray photoelectron spectroscopy (XPS) spectrum for
Cu 2p of CoCuFe O
2 4
scanning electron microscopy, vibrating‐sample magne-
tometry, X‐ray diffraction, energy‐dispersive X‐ray spec-
trometry, transmission electron microscopy and Fourier
[25]
transform‐infrared analysis
(see Supporting Informa-
tion), these XPS results further confirmed the formation
of cobalt‐copper ferrite.
Our catalytic system, in comparison with previously
[28,29]
reported palladium or copper‐based catalysts,
not
only has low cost but is also readily prepared in a few
steps from available starting materials and can be
removed easily from the reaction media due to its
ferromagnetic nature. This is a very important factor for
creating non‐polluting catalysts, because the trace
amount of metal contamination could have undesired
effects on human‐life‐related products.
After the establishment of the optimized conditions,
this protocol was applied to access a variety of arylamines
(Table 2). Phenylboronic acids with an electron‐releasing
group (OCH ) afforded slightly better yields than did
3
those with electron‐withdrawing groups (NO2).
Our research has focused on the reduction of costs by
the creation of highly active catalysts, and on the reduc-
tion of waste by developing a halide‐free amination/
sulfidation reaction based on the use of arylboronic acids
as arylating agents. Therefore, due to the employment of
arylboronic acids as an arylating surrogate, atom econ-
omy was improved compared with the systems that used
aryl halides. From the perspective of process develop-
ment, there is a strong demand to simplify reactions as
much as possible. In this respect, we report the catalytic
system that possesses no ligands and is still capable of
effectively catalyzing the construction of the carbon‐
heteroatom bond. In fact, the presence of ligands can be
a nuisance, particularly at high catalyst loadings, as they
are often hard to separate from the product.
After achieving excellent results with aliphatic
acyclic amines such as diethyl amine, dibutylamine,
benzylamine, propylamine and N,N dicyclohexyl amine,
we further applied this catalytic system for the N‐
arylation of aromatic and cyclic aliphatic amines. In the
case of aromatic amines, those including electron donor
substituents afforded the corresponding arylated products
in higher yields compared with amine‐bearing electron‐
withdrawing groups. The aliphatic boronic acid (but‐1‐
yn‐1‐ylboronic acid) was also examined and the
corresponding product obtained in moderate yield (1s).
Pyridin‐3‐ylboronic acid was chosen as a heteroaromatic
boronic acid provided the corresponding products
3‐(1H‐imidazol‐1‐yl) pyridine in low yield (1t).
One of the most important issues associated with the
heterogeneous catalyst is its recyclability. In this regard,
the yield of the model product (the reaction of aniline with
phenylboronic acid) in the presence of the fresh
We set out a route by which disadvantages associated
with the classical cross‐coupling reactions, such as the need
for presynthesizing of starting materials and consequently

4
of 8
MOGHADDAM ET AL.
a
TABLE 1 Optimization of reaction conditions on amination reaction of phenylboronic acid with aniline in the presence of catalyst
b
Entry
Base
Et
DABCO
CO
KOH
Solvent
Catalyst (mol%)
Temperature (°C)
Yield (%)
1
2
3
4
5
6
7
8
9
3
N
CH
CH
CH
CH
CH
CH
CH
3
3
3
3
3
3
3
OH
OH
OH
OH
OH
OH
OH
2.5
2.5
2.5
2.5
2.5
2.5
2.5
2.5
2.5
2.5
2.5
2.5
2.5
2.5
2.5
5
60
60
60
60
60
60
60
60
60
60
60
60
60
60
60
60
40
R.T.
80
60
50
45
54
70
60
52
57
20
82
32
78
21
25
30
80
88
30
N.R.
89
N.R.
K
2
3
KOAc
NaHCO
KOtBu
KOH
KOH
KOH
KOH
KOH
KOH
KOH
KOH
KOH
KOH
KOH
KOH
KOH
3
2
H O
EtOH
10
11
12
13
14
15
16
17
18
19
20
CH
3
2
CN
Cl
CH
2
Toluene
1,4 Dioxane
DMSO
DMF
EtOH
EtOH
5
EtOH
5
EtOH
5
EtOH
–
N.R., No Reaction; R.T., Room Temperature.
a
Reaction conditions: phenylboronic acid (0.1 mmol), aniline (0.2 mmol), base (0.15 mmol), solvent (1 ml), 5 h.
b
Isolated yields.
CoCuFe O was compared with those of reused catalysts.
Cs CO . All proved inferior to n‐Bu NOH (40%, aq.) in
2
4
2
3
4
In this line, the recovered catalyst was washed with EtOH,
dried and reused for consecutive reaction runs. The results
showed that the catalyst could be recovered and reused for
five reaction runs with a slight loss of the catalytic activity
for the reaction of aniline and phenylboronic acid under
optimized reaction conditions (Figure S10).
Encouraged by obtaining outstanding results in the
amination reaction, we next tested the efficiency of cata-
lyst for the coupling reaction of thiols with aryl boronic
acids. The optimal reaction conditions were elaborated
in the reaction of phenylboronic acid and thiophenol.
The data from the optimization reactions are shown in
Table 3. First, various solvents were tested. Running the
reaction in ethanol afforded the desired product in poor
terms of yield.
We tried to accelerate the rate of coupling by raising
reaction temperature. However, through enhancing the
reaction temperature up to 120°C no perceptible increase
in the reaction yield was observed.
As a final step, the dependence of the results on catalyst
loading was tested. Reducing the catalyst amount from 5
mol% to 2.5 mol% led to a significant drop in yield from
83% to 56%. A further increase of the catalyst amount to
10 mol% could not improve the result to a better extent.
The reaction was shut down in the absence of catalyst.
Armed with the optimum reaction conditions, the
generality of this protocol was examined by using various
substrates with different electronic properties. As shown
in Table 4, the reaction can be conducted using both
linear and aromatic sulfides.
The reactions of substituted thiophenols bearing both
electron‐donating and electron‐withdrawing groups with
phenylboronic acid proceeded smoothly leading to the
desired products in high yields. The results also indicated
that the electronic effect of substituents on the benzene
2
0% yield (Table 3, entry 6), and the use of DMSO,
DCE, THF and dioxane as solvents afforded product in
small amounts. However, we noted that a good yield
(83%) of the desired product could be obtained in DMF.
The study was further carried out using different
bases, including organic and traditional inorganic ones
such as NaOH, K CO , KOtBu, KOAc, NaHCO and
2
3
3

MOGHADDAM ET AL.
5 of 8
a
TABLE 2 N‐arylation of amines with phenylboronic acids
1
1
a/H 88
e/H 85
1b/H 91
1d/H 89
1
c/H 90
1h/H 92
1
g/H 92
1f/H 90
1j/H 90
1l/H 90
1i/OCH3 90
1k/H 89
1p/H 75
1
m/NO2 74
1
o/H 73
1
1
n/H 76
r/H 87
1t 22
1s 56
1
q/H 86
a
Reaction conditions: arylboronic acid (0.1 mmol), amine (0.2 mmol), KOH (0.15 mmol), EtOH(1 ml), 60°C, 5 h.
[
31]
ring of arylboronic acid has limited influence on this het-
erogeneous catalyzed Chan–Lam coupling reaction. More
strongly electron‐donating (methoxy) or electron‐with-
drawing (nitro) substitutions do not significantly affect the
reaction overall yields. The coupling of cyclohexylboronic
acid as an aliphatic boronic acid with thiophenol only gave
a trace amount of product (2m). However, the reaction of 3‐
thiopheneboronic acid with thiophenol provided the corre-
sponding product in moderate yield (2n).
coupling reaction.
As depicted in Scheme 1, the reac-
tion pathway starts with transmetallation of arylboronic
acid, which is in equilibrium with the boronate ester,
to afford intermediate A and releasing boric acid. This step
is a turnover‐limiting step. In fact, the nanoparticles may
facilitate the coupling reactions due to the easier transfer
of electrons and the higher surface area in comparison to
[32]
−
bulk metal salts. Then, RX (where X = S, N) derived from
RXH and base coordinates to intermediate A to form inter-
mediate B. Finally, intermediate B produced the desired
product and completed the catalytic cycle. In support of
this mechanistic speculation, no disulfide was observed
as an intermediate during the reaction followed by GC.
By this catalytic system, desired products were formed
with yields comparable with the previous catalytic
system. Another advantage is that reactions required
approximately shorter times to be completed, indicating
better activity of the CoCuFe O nanoparticles. In addi-
In continuation, the separation of CoCuFe O nano-
2
4
particles from the reaction mixture was studied using an
external magnetic rod. We have studied the possibility
of catalyst recycling from the reaction of thiophenol with
phenylboronic acid under optimized reaction conditions.
After each reaction cycle, the catalyst was separated by
an external magnet rod, rinsed with ethanol several
times, dried, and reused for the subsequent reaction for
five consecutive runs (Figure S11).
2
4
Considering the fact that the reaction could not pro-
ceed without CoCuFe O and along with recent published
work led us to propose a mechanism for the Chan–Lam
tion, this spinel catalyst is cheaper and more effective
than previous palladium‐based catalytic systems and their
raw materials are available.
2
4

6
of 8
MOGHADDAM ET AL.
TABLE 3 Optimization of reaction conditions on the Chan–Lam reaction of phenylboronic acid with thiophenol in the presence of
a
catalyst
Entry
Solvent
Base
Temperature (°C)
Catalyst (mol%)
Isolated yield (%)
1
2
3
4
5
6
7
8
9
DMSO
DMF
DCE
NaOH
NaOH
NaOH
NaOH
NaOH
NaOH
100
5
69
72
45
40
32
20
50
53
51
49
60
70
74
83
58
84
56
84
N.R.
100
5
Reflux
Reflux
100
5
THF
5
Dioxane
EtOH
DMF
DMF
DMF
DMF
DMF
DMF
DMF
DMF
DMF
DMF
DMF
DMF
DMF
5
Reflux
100
5
K
2
CO
3
5
KOtBu
KOAc
100
5
100
5
10
11
12
13
14
15
16
17
18
19
NaHCO
3
100
5
Cs
Et
Pyridine
2
CO
3
100
5
3
N
100
5
100
5
n‐Bu
n‐Bu
n‐Bu
n‐Bu
n‐Bu
n‐Bu
4
4
4
4
4
4
NOH (40% aq.)
NOH (40% aq.)
NOH (40% aq.)
NOH (40% aq.)
NOH (40% aq.)
NOH (40% aq.)
100
5
80
5
120
5
100
2.5
10
–
100
100
N.R., No Reaction.
a
2
Reaction conditions: PhB (OH) (0.5 mmol), thiophenol (0.7 mmol), base (1.5 mmol), solvent (1 ml), 10 h.
a
TABLE 4 Cobalt‐copper ferrite nanoparticles catalyzed thioetherification of different sulfides and arylboronic acids
2
a/80
2b/81
2c/85
2d/86
2
e/83
2f/80
2h/85
2
g/87
2k/73
2i/87
2j/82
2 l/76
2
m/21
2n/56
a
4
Reaction conditions: arylboronic acid (0.5 mmol), sulfide (0.7 mmol), n‐Bu NOH (0.15 mmol), DMF (1 ml), 100°C, 10 h.

MOGHADDAM ET AL.
7 of 8
SCHEME 1 Proposed mechanism for
Chan–Lam cross‐coupling reaction
catalyzed by cobalt‐copper ferrite
3
| CONCLUSION
prepared separately and mixed together. The solution
was stirred for 1 h. Then, in order for pH to reach 11, a
solution of NaOH (0.3 M) was added slowly to the flask.
Finally, oleic acid (3 drops) was added to the solution as
a surfactant to prevent the aggregation and agglomera-
tion of the nanoparticles. Then, the suspension was vigor-
ously stirred using a magnetic stirring bar at 60°C for 2 h.
After complete precipitation, the residue was washed
with double‐distilled water (3 × 25 ml) and dried in an
oven at 90°C overnight; then it was calcinated at 600°C
for 4 h. The final product is a black powder showing
magnetic properties.
In summary, this newly developed method demonstrates
a new alternative to the existing method that is cost effec-
tive and an atom‐economic approach to C‐heteroatom
bond formation. This report introduces a mild, green
and practical method for preparation of N‐arylamines
via the coupling reaction of aryl boronic acid with diver-
sity of amines including primary and secondary ones in
high yields. The catalyst was also successfully applied
for unsymmetrical sulfides through coupling reaction of
thiols with phenyl boronic acid as an arylating surrogate.
Using inexpensive catalyst and user‐friendly starting
materials have made these methods valuable for C‐N
and C‐S bond formation. The magnetic nature of the
catalyst enables it to be easily removed from the reaction
mixture by an external magnet, which prevails the issues
associated with the filtering separation method.
4.3 | General procedure for amination
reaction
A glass tube was charged with phenylboronic acid
(1 mmol), amine (1.2 mmol), KOH (1.5 mmol), EtOH
(
1 ml) and CoCuFe O (5 mol%). The reaction mixture
2 4
was stirred at 60°C until the completion of the reaction,
4
4
| EXPERIMENTAL
which was monitored by thin‐layer chromatography
(
TLC; EtOAc/n‐hexane, 25:75). In each case, after com-
.1 | Reagents and analyses
pletion, the mixture was diluted with ethyl acetate and
water. The organic layer was washed with brine, dried
All materials used are commercially available, and were
purchased from Merck and used without any additional
purification. H NMR and
recorded on a Bruker (Avance DRX‐500) spectrometer
using CDCl or DMSO‐d as solvent at room temperature.
Chemical shifts δ were reported in ppm relative to
tetramethylsilane as an internal standard. XPS analysis
was performed using a VG multilab 2000 spectrometer
over MgSO and concentrated under reduced pressure
4
using a rotary evaporator. The residue was purified by
column chromatography on silica gel (n‐hexane/EtOAc,
1
13
C NMR spectra were
7
5:25). All products were known compounds and were
3
6
1
identified by comparison of their H NMR spectra with
those of authentic samples.
[
33]
(ThermoVG scientific) in an ultrahigh vacuum.
4.4 | General procedure for sulfidation
reaction
A mixture of phenylboronic acid (0.5 mmol), thiol
4
.2 | Synthesis of CoCuFe O4
2
(
0.7 mmol), n‐Bu NOH (1.5 mmol) and CoCuFe O
4
2 4
The solutions of iron chloride (FeCl ·6H O; 100 ml, 0.1
(5 mol%) was added to DMF (1 ml) in a round‐bottomed
flask equipped with magnet and condenser. The reaction
mixture was stirred at 100°C until the completion of the
3
2
M), copper chloride (CuCl ·2H O; 100 ml, 0.02 M) and
2
2
cobalt chloride (CoCl ·6H O; 100 ml, 0.03 M) were
2
2

8
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MOGHADDAM ET AL.
reaction, which was monitored by TLC (EtOAc/n‐hexane,
5:75). In each case, after completion, the mixture was
[17] P. S. Herradura, K. A. Pendola, R. K. Guy, Org. Lett. 2000, 2,
2019.
2
diluted with ethyl acetate and water. The organic layer
[18] K. S. Rao, T. S. Wu, Tetrahedron 2012, 68, 7735.
[19] J. X. Qiao, P. Y. Lam, Synthesis 2011, 2011, 829.
was washed with brine, dried over MgSO and concen-
4
trated under reduced pressure using a rotary evaporator.
The residue was purified by column chromatography on
silica gel (n‐hexane/EtOAc, 75:25). All products were
known compounds and were identified by comparison
[
20] P. Y. S. Lam, S. Deudon, K. M. Averill, R. Li, M. Y. He, P.
Deshong, C. G. Clark, J. Am. Chem. Soc. 2000, 122, 7600.
[
[
21] G. I. Elliott, J. P. Konopelski, Org. Lett. 2000, 2, 3055.
22] P. Lopez‐Alvarado, C. Avendano, J. C. Menendez, J. Org. Chem.
1
of their H NMR spectra with those of authentic
1996, 61, 5865.
[34,35]
samples.
[23] P. Lopez‐Alvarado, C. Avendano, J. C. Menendez, Tetrahedron
Lett. 1992, 33, 659.
[24] D. M. T. Chan, Tetrahedron Lett. 1996, 37, 9013.
ACKNOWLEDGEMENTS
[
25] F. M. Moghaddam, R. Pourkaveh, M. Ahangarpour, Catal.
Commun. 2017, 102, 71.
The authors gratefully acknowledge the funding support
received for this project from the Sharif University of
Technology (SUT), Islamic Republic of Iran.
[
[
26] W. P. Wang, H. Yang, T. Xian, J. L. Jiang, Mater. Trans. 2012,
53, 586.
27] N. Fradette, B. Marsan, J. Electrochem. Soc. 1998, 145, 2320.
ORCID
[28] A. R. Hajipour, R. Pourkaveh, H. Karimi, Appl. Organomet.
Chem. 2014, 28, 879.
Firouz Matloubi Moghaddam
418-9888
http://orcid.org/0000-0002-
[
[
29] Y. Uozumi, N. Kai, Synfacts. 2016, 12, 0314.
8
30] A. Klapars, X. Huang, S. L. Buchwald, J. Am. Chem. Soc. 2002,
124, 7421.
REFERENCES
[31] P. Rani, R. Srivastava, Tetrahedron Lett. 2014, 55, 5256.
[32] D. G. Hall, Boronic Acids, Wiley‐VCH, Weinheim 2005.
[
1] S. H. Cho, J. Y. Kim, J. Kwak, S. Chang, Chem. Soc. Rev. 2011,
0, 5068.
4
[
[
[
33] S. Roy, M. J. Sarma, B. Kashyap, P. Phukan, Chem. Commun.
016, 52, 1170.
34] Y. Lin, M. Cai, Z. Fang, H. Zhao, Tetrahedron 2016, 72,
335–3343.
2
[
[
[
[
[
[
[
2] F. Ullmann, Ber. Dtsch. Chem. Ges. 1903, 36, 2382.
3] I. Goldberg, Ber. Dtsch. Chem. Ges. 1906, 39, 1691.
4] M. Kosugi, M. Kameyama, T. Migita, Chem. Lett. 1983, 12, 927.
5] J. F. Hartwig, Synlett. 2006, 1283.
3
35] F. Ding, Y. Jiang, S. Gan, R. L. Y. Bao, K. Lin, L. B. Shi, Eur. J.
Org. Chem. 2017, 3427.
6] D. S. Surry, S. L. Buchwald, Chem. Sci. 2011, 2, 27.
7] C. E. Garett, K. Prasad, Adv. Synth. Catal. 2004, 346, 889.
8] S. Ma, H. Wang, K. Gao, F. Zhao, J. Mol. Catal. A Chem. 2006,
SUPPORTING INFORMATION
Additional supporting information may be found online
in the Supporting Information section at the end of the
article.
2
48, 17.
[
9] S. G. Babu, N. Neelakandeswari, N. Dharmaraj, S. D. Jackson,
R. Karvembu, RSC Adv. 2013, 3, 7774.
[
[
10] A. R. Hajipour, G. Azizi, Green Chem. 2013, 15, 1030.
How to cite this article: Moghaddam FM,
Pourkaveh R, Gholamtajari M. Nano CoCuFe O ‐
11] Y. Ikeda, T. Nakamura, H. Yorimitsu, K. Oshima, J. Am.Chem.
Soc. 2002, 124, 6514.
2
4
catalyzed coupling reaction of arylboronic acid
with amines and thiols: An atom‐economic and
ligand‐free route to access unsymmetrical amines
and sulfides. Appl Organometal Chem. 2018;e4568.
https://doi.org/10.1002/aoc.4568
[
[
[
[
[
12] R. Jana, T. P. Pathak, M. S. Sigman, Chem. Rev. 2011, 111, 1417.
13] F. M. Moghaddam, R. Pourkaveh, Catal. Commun. 2017, 94, 33.
14] I. Beletskaya, V. Tyurin, Molecules 2010, 15, 4792.
15] N. Toshima, T. Yonezawa, New J. Chem. 1998, 22, 1179.
16] J. L. Bolliger, C. M. Frech, Tetrahedron 2009, 65, 1180.