An efficient glucose-based ligand for Heck and Suzuki coupling reactions in aqueous media

Article abstract of DOI:10.1007/s13738-013-0316-3

The glucose-based ligand, N-salicylidene-d-glucosamine (Sal-d-glsmN), was readily obtained by reaction of salicylaldehyde (Hsal) with the d-glucosamine hydrochloride. Ligand Sal-d-glsmN was found to be an efficient ligand in the palladium-catalyzed Suzuki and Heck C-C coupling reactions in aqueous medium under aerobic condition. It was found that the use of Sal-d-glsmN/Pd(OAc) ₂ system as a catalyst, aryl halides undergo Suzuki and Heck cross-couplings, respectively, with arylboronic acids and olefins to give the desired products in moderate to excellent yields.

Full text of DOI:10.1007/s13738-013-0316-3

J IRAN CHEM SOC
DOI 10.1007/s13738-013-0316-3
ORIGINAL PAPER
An efficient glucose-based ligand for Heck and Suzuki coupling
reactions in aqueous media
•
Mojtaba Bagherzadeh Mojtaba Amini
•
•
Parviz Gohari Derakhshandeh
Mohammad Mehdi Haghdoost
Received: 2 January 2013 / Accepted: 17 July 2013
Ó Iranian Chemical Society 2013
Abstract The glucose-based ligand, N-salicylidene-D-
glucosamine (Sal-D-glsmN), was readily obtained by
reaction of salicylaldehyde (Hsal) with the D-glucosamine
hydrochloride. Ligand Sal-D-glsmN was found to be an
efficient ligand in the palladium-catalyzed Suzuki and
Heck C–C coupling reactions in aqueous medium under
aerobic condition. It was found that the use of Sal-D-
glsmN/Pd(OAc)2 system as a catalyst, aryl halides undergo
Suzuki and Heck cross-couplings, respectively, with aryl-
boronic acids and olefins to give the desired products in
moderate to excellent yields.
reactions due to low cost, non-flammability, non-toxicity,
and environmental hazards [1–3].
Palladium-catalyzed cross-coupling reactions such as
Suzuki and Heck have been demonstrated to be one of the
most widely used standard tools for the construction of
carbon–carbon bonds [4–8]. In general, improvement of
palladium-catalyzed reactions is greatly based on the
reactivity of the palladium catalyst using efficient sup-
porting ligands [9–14]. Therefore, during the past decades
many efforts have been made to find most efficient ligands,
in which phosphine-based ligands are used as the most
common ligands for Suzuki and Heck coupling reactions
[15–17]. However, most of the phosphine-based ligands are
water and/or air sensitive. Therefore, it is highly desirable
to design the water soluble, efficient, and phosphine-free
ligands to dispense the use of expensive and water and/or
air-sensitive phosphines for palladium-catalyzed coupling
reactions.
Keywords Homogeneous catalysis ꢀ
C–C coupling ꢀ Heck reaction ꢀ Suzuki reaction
Introduction
In recent years, replacing conventional reagents with
environment friendly reagents have vigorously been stud-
ied from the standpoint of green chemistry and water is
preferred in studies as an attractive solvent for chemical
Sugars as the most naturally abundant organic molecules
with many hydroxyl groups, which tend to increase the
solubility of these molecules in water, are suitable
resources for synthesis of water soluble ligand with base of
sugar [18]. Furthermore, the structural diversity of sugar
and the high density of functional groups offer a wide
variety of opportunities for successful utilization of sugars
in many technically important fields such as asymmetric
induction in a reaction using sugar derivatives as chiral
auxiliaries [19–21]. The very cheap, especially high envi-
ronmental friendly nature of sugar molecules has driven us
to explore their capabilities as ligands for Heck and Suzuki
coupling reactions in aqueous medium.
Electronic supplementary material The online version of this
article (doi:10.1007/s13738-013-0316-3) contains supplementary
material, which is available to authorized users.
M. Bagherzadeh (&) ꢀ P. G. Derakhshandeh ꢀ M. M. Haghdoost
Chemistry Department, Sharif University of Technology,
P.O. Box 11155-3516, Tehran, Iran
e-mail: bagherzadeh@sharif.edu
M. Amini (&)
To develop a general catalyst for palladium-catalyzed
cross-coupling reactions, we decided to apply a green
system Pd(OAc)2/Glucose-based ligand for the preparation
of polysubstituted alkenes by Suzuki cross-couplings of
Department of Chemistry, Faculty of Science, University
of Maragheh, Golshahr, P.O. Box 55181-83111731,
Maragheh, Iran
e-mail: mamini@maragheh.ac.ir
123

J IRAN CHEM SOC
aryl halides with arylboronic acids and Heck reaction of
olefins with aryl halides.
Results and discussion
The synthetic path for the glucose-based ligand, N-salicy-
lidene-D-glucosamine (Sal-D-glsmN) is depicted in
Scheme 1. Ligand Sal-D-glsmN was obtained by deproto-
nation of glucosamine hydrochloride with NaOH in MeOH
following the addition of salicylaldehyde and stirring the
reaction mixture at 35 °C for 2 h [22].
Fig. 1 The effect of base and solvent on the Heck reaction. Reaction
conditions: 1.0 mmol of iodobenzene, 1.2 mmol of n-butyl acrylate,
2 mmol of bases, 1.0 mol % Pd(OAc)2, (2 mol %) ligand Sal-D-
glsmN, 80 °C, 3-mL solvent, 2 h
The next investigation is to study the catalytic perfor-
mance of the synthesized glucose-based ligand in the pal-
ladium-catalyzed Heck reaction in aqueous medium. We
chose the palladium-catalyzed Heck coupling of iodoben-
zene with n-butyl acrylate as the test reaction for optimi-
zation of the reaction conditions. A wide variety of
solvents has been used for Pd-catalyzed Heck reactions and
the selection of solvents with low toxicity is of primary
interest. Water alone or in association with iPrOH or DMF
represents the most economical and safety-conscious sol-
vent combination [23, 24]. As shown in Fig. 1, (2:1)
mixture of H2O/DMF or H2O/iPrOH was found to be the
best of choice in presence of KOH as base. It is well known
that the addition of a base can improve the reaction effi-
ciency for some catalytic system. Subsequently, the reac-
tion was investigated in the presence of different bases in
(2:1) mixture of H2O/DMF as solvent. Interestingly, it was
found that some inorganic bases, such as K2CO3 and KOH,
promoted the Heck coupling reaction, giving excellent
yields. On the other hand, NEt3 as an organic base had little
effect on the reaction.
electronic nature of substituents bearing olefins is initially
investigated. Various olefins bearing either electron-
donating groups or electron-withdrawing groups such as
methoxy, methyl and cyano groups, could be efficiently
converted to the corresponding coupling products in good
to high yields. A mixture of the two stereoisomers ([Z] and
[E]) was obtained for the reaction of acrylonitrile (Table 1,
entry 5). It is well know that electron-poor aryl halides
undergo Heck reactions more easily than electron-rich
substrates and this general trend has been observed for both
aryl bromides and chlorides (Table 1, entries 11–18). It is
worth noting that the most electron-poor aryl bromide,
4-acetylbromobenzene, showed a good reactivity and was
successfully coupled with styrene and n-butylacrylate in
good yields (Table 1, entries 11, 12). However, the Heck
coupling of chlorobenzenes was difficult to proceed under
the same reaction conditions and trace amounts of coupling
product was observed (Table 1, entries 17–19).
To broaden the catalytic applicability of the Sal-D-
glsmN ligand, we subsequently examined Heck coupling
reactions of iodobenzene and boromobenzene with various
olefins (Table 1).
In general, coupling of aryl iodides and bromides with
olefins was found to give products in good to excellent
yields (47–97 %). The reduced yields of chlorobenzenes
are mostly a consequence of non-reactive nature of this
substrate.
The results indicated that the combination of Pd(OAc)2
and the Sal-D-glsmN was efficient for the Heck coupling
reaction of a series of alkenes and aryl halides. The
It is clear that ligands with coordination to palladium
during the catalytic process of the Heck reaction could
improve the stability of palladium complexes and, there-
fore, the catalytic activity induced by ligands is indeed
better than ligandless conditions [25]. To study the coor-
dination of ligand Sal-D-glsmN to palladium and complex
formation during the catalytic process, the electronic
spectra of Pd(OAc)2, ligand Sal-D-glsmN and Pd(OAc)2/
Sal-D-glsmN ligand mixture were recorded in H2O/DMF
(1:1 v/v) solution and are presented in Fig. 2. It was found
that after addition of 1 equiv. of Pd(OAc)2 to the solution
of ligand Sal-D-glsmN, the band at 317 nm of ligand
slightly shifted to longer wavelength along with decreasing
in its intensity. Conversely, the band at kmax = 388 nm
HOCH2
O
HO
HO
HOCH2
1)
NaOH, CH3OH
N
OH
O
HO
HO
CHO
2)
+
OH
OH
NH3
OH
Cl -
Scheme 1 The synthetic path of glucose-based ligand N-salicylid-
ene-D-glucosamine
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J IRAN CHEM SOC
exhibits a distinct hypsochromic shift followed by gradual
increase in this band intensity. On the basis of spectral
results, one could assume the formation of new species of
type Pd- Sal-D-glsmN as a catalytic complex involved in
the reaction.
Table 1 Heck reaction between aryl halides and olefins
Entry
ArX
Olefin
Yield (%)a (TON, TOF(h-1))b
H2O/DMF
88 (88, 44)
H2O/ iPrOH
1
2
3
4
5
66 (66, 33)
I
In order to show the merit and efficiency of the present
catalytic system in comparison with recently reported
protocols, we compared the results of the stilbene synthesis
from iodobenzene and styrene in the presence of palladium
catalysts. As shown in Table 2, our catalytic system is
superior to some of the previously reported catalysts in
terms of reaction conditions. In contrast to similar previ-
ously reported systems, the catalytic system presented in
this paper does not suffer from the harsh reaction condi-
tions, such as high reaction temperature (Table 2, entries
2–4 and 6), long reaction time (Table 2, entries 2–4, 6, 7,
10, 11, and 12), and using large amounts of hazardous
solvents (Table 2, entries 2–6). In addition, the attractive
features of this catalytic system, such as low cost, and ease
of use, make it particularly suitable for the coupling
reactions.
COOBu
97 (97, 48.5)
96 (96, 48)
81 (81, 40.5)
73 (73, 36.5)
67 (67, 33.5)
72 (72, 36)
I
COOMe
COOEt
CN
I
I
I
95 (95, 47.5)
97d (97, 48.5)
6
7
85 (85, 42.5)
83 (83, 41.5)
70 (70, 35)
I
I
65 (65, 32.5)
CH3O
COOBu
COOBu
8
9
79 (79, 39.5)
73 (73, 36.5)
72 (72, 36)
56 (56, 28)
54 (54, 27)
54 (54, 27)
MeO
MeO
I
I
The operationally simple, air-stable, and water soluble
nature of the catalytic system Pd(OAc)2/Sal-D-glsmN
inspired us to investigate its scope in the Suzuki reaction. It
is known that the nature of the solvent and base is an
important factor for determining the efficiency of the Su-
zuki cross-coupling reaction. Therefore, the influence of
various solvents and bases was firstly investigated for the
Pd(OAc)2 catalyzed Suzuki coupling reaction of iodoben-
zene with phenylboronic acid in present of Sal-D-glsmN
ligand. The results in Fig. 3 show that (3:1) mixture of
H2O/iPrOH performed most efficiently as solvent system
among the various solvents screened, whereas KOH is the
10
I
OMe
11
12
70 (70, 35)
76 (76, 38)
63 (63, 31.5)
61 (61, 30.5)
CH3CO
CH3CO
Br
Br
COOBu
COOBu
13
14
61 (61, 30.5)
59 (59, 29.5)
52 (51, 25.5)
50 (50, 25)
MeO
MeO
Br
Br
COOBu
COOBu
15
55 (55, 27.5)
47 (47,23.5)
Br
OMe
Br
16
17
64 (64, 32)
51 (51, 25.5)
trace
27 (27, 13.5)
CH3CO
CH3CO
Cl
COOBu
COOBu
18
19
30 (30, 15)
13 (13, 6.5)
trace
trace
Cl
Cl
Reaction conditions: 1.0 mmol of aryl halide, 1.2 mmol of olfins,
2 mmol of K2CO3, 1.0 mol % Pd(OAc)2, (2.0 mol %) ligand Sal-D-
glsmN, 80 °C, 3-mL solvent, 2 h
Isolated yield
a
TON = (mmol of product)/mmol of catalyst, TOF = TON/reaction
Fig. 2 UV–vis spectra of a 0.02-M solution of Pd(OAc)2, b ligand
Sal-D-glsmN, c Pd(OAc)2/ligand Sal-D-glsmN mixture in H2O/DMF
(1:1 v/v)
time
b
Ratio (Z:E) is 23:77
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J IRAN CHEM SOC
Table 2 Recently reported catalytic systems for Heck reaction by palladium catalysts
I
Pd catalyst
+
Entry Catalyst
Conditions
Yield (%) TON
Ref.
1
Pd(OAc)2-Sal-D-glsmN
N,N0,N00,O-tetradentate Pd(II)
1 mol % catalyst/K2CO3/H2O:DMF(2:1)/2 h/80 °C
0.001 mol % catalyst/LiOH/DMF/15 h/140 °C
0.001 mol % catalyst/K2CO3/DMF/24 h/140 °C
0.001 mol % catalyst/K2CO3/DMF/24 h/140 °C
1 mol % catalyst/K2CO3/DMF/30 min/100 °C
0.004 mol % catalyst/NEt3/DMAc/8 h/120 °C
0.002 mol % catalyst/K2CO3/H2O/8 h/100 °C
88
88 Present work
2
95
95,000 [26]
3
Trans-[PdCl2(PI)2]
92
92,000 [27]
98,000 [27]
75 [28]
4
Trans-[PdBr2(MPI)2]
Aminophosphine-pd(II)
Oxazine-Pd(II)
98
5
75.2
94
6
23,500 [29]
45,000 [30]
13 [31]
7
Kraft lignin Pd NPs
100
98
8
Poly(N-vinyl-2-pyrrolidone) Pd NPs 7.5 mol % catalyst/K2CO3/H2O/1 h/60 °C
9
Pd NPs-nSTDP
0.01 mol % catalyst/K2CO3/H2O:DMF(1:3)/9 h/85 °C 95
9,500 [32]
79 [33]
10
11
12
13
PNP–SSS
1.2 mol % catalyst/K2CO3/H2O/1.5 h/100 °C
0.025 mol % catalyst/NEt3/MeOH/18 h/reflux
0.025 mol % catalyst/NEt3/MeOH/18 h/reflux
0.03 mol % catalyst/K2CO3/MeOH/4 h/reflux
95
91
82
95
Pd/Cu (4:1) NPs
Pd/Cu (5:1) NPs
Diazoketiminato-pd(II)
5,921 [34]
5,335 [34]
3,333 [35]
100
80
60
40
20
0
0
1
2
3
4
5
Fig. 3 The effect of base and solvent on the Suzuki reaction.
Reaction conditions: 1.0 mmol of iodobenzene, 1.2 mmol of phen-
ylboronic acid, 2 mmol of bases, 0.5 mol % Pd(OAc)2, (1 mol %)
ligand Sal-D-glsmN, 85 °C, 3-mL solvent
Time (h)
Fig. 4 Kinetic profile of Pd(OAc)2/Sal-D-glsmN catalyzed Suzuki
reaction in (2:1) mixture of H2O/iPrOH. Reaction conditions:
1.0 mmol of iodobenzene, 1.2 mmol of phenylboronic acid, 2 mmol
of KOH, 0.5 mol % Pd(OAc)2, 1 mol % ligand Sal-D-glsmN, 85 °C,
3 mL (3:1) mixture of H2O/iPrOH
best choice as compared to the other bases in (3:1) mixture
of H2O/iPrOH as solvent. The activity towards cross-cou-
pled product biphenyl was decreased when KOH was
replaced with K2CO3, NEt3, NaOAc, and K3PO4.
To evaluate the catalytic performance of the Sal-
D-glsmN ligand, a kinetic study of the Suzuki reaction
between iodobenzene and phenylboronic acid was per-
formed in the presence of Pd(OAc)2 and KOH at 85 °C in
(3:1) mixture of H2O/iPrOH.
provided good to excellent yield of the products. The
reaction between iodobenzene and phenylboronic acid
was quantitative and faster with the use of 0.5 mol % of
Pd(OAc)2 in (3:1) mixture of H2O/iPrOH. High catalytic
activity was observed in the coupling of phenylboronic
acid and 4-methoxyphenylboronic acid with both aryl
iodide and bromide. 2-methoxyphenylboronic acid was
less reactive in comparison to phenylboronic acid and
4-methoxy phenylboronic acid, indicating that the steric
affect of the substrates play a significant role in this
system (Table 3, entries 1 and 5). In addition, Pd(OAc)2/
Sal-D-glsmN system showed good activity for the Suzuki
reaction of phenylboronic acids with aryl iodide and aryl
bromide in pure water. It is worth noting that the most
Figure 4 demonstrates the kinetic curves of the reaction
time vs. the isolated yield using in situ-generated catalysts
from Pd(OAc)2.
The catalytic applicability of the Sal-D-glsmN ligand
was explored with a range of aryl halides and arylboronic
acids and the results are summarized in Table 3.
As shown in Table 3, the Suzuki coupling of various
phenylboronic acids with aryl iodide and bromide
123

J IRAN CHEM SOC
materials. The in situ-generatedcatalysts from Pd(OAc)2 and
the Sal-D-glsmN ligand demonstrated excellent catalytic
activities towards the Suzuki reaction of aryl halides and
various phenylboronic acids while using pure water or H2O/
iPrOH as the green solvent. In additon, catalytic system Sal-
D-glsmN/Pd(OAc)2 was used in Heck coupling reactions of
iodobenzene and boromobenzene with various olefins in
aqueous medium. Under aerobic conditions, good to excel-
lent yields of coupled product were obtained.
Table 3 Suzuki reaction between aryl halides and aryl boronic acids
Entry
ArX
Olefin
Yield (%)a (TON)b
H2O
H2O/
iPrOH
1
2
96 (192)
51 (102)
98 (196)
I
O
69(138)
I
3
4
79 (158)
90 (180)
92 (184)
95 (190)
O
I
Experimental section
Br
O
5
45 (90)
61(122)
General remarks
Br
Br
All the reactions were carried out under air. Chemicals
and solvents were purchased from the Fluka and Merck
Chemical companies and used without purification. The
elemental analysis (carbon, hydrogen, and nitrogen) of
compounds were obtained from a Carlo ERBA Model EA
1108 analyzer. UV–Vis spectra were recorded by a CARY
6
7
81 (162)
96 (192)
86 (172)
98 (196)
O
CH3CO
CH3CO
Br
8
25 (50)
16 (32)
Cl
1
100 Bio VARIAN UV–vis spectrophotometer. The H and
13C NMR spectra were recorded on a Bruker FT-NMR
500 MHZ spectrometer. Chemical shifts are reported in
ppm relative to TMS. The reaction products of Heck
reaction were determined and analyzed by a HP Agilent
6890 gas chromatograph equipped with a HP-5 capillary
column (phenyl methyl siloxane 30 m ꢀ 320 lm ꢀ 0.25
lm) and a flame-ionization detector. All products were
isolated by short chromatography on a silica gel 60
(0.063–0.20 mesh ASTM) column using hexane/ethyl
acetate as eluent.
Reaction conditions: 1.0 mmol of aryl halide, 1.2 mmol of arylbo-
ronic acid, 2 mmol of KOH, 0.5 mol % Pd(OAc)2, (1.0 mol %)
ligand Sal-D-glsmN, 85 °C, 4 h, 3-mL solvent
a
Isolated yield
b
TON = (mmol of product)/mmol of catalyst
electron-poor aryl bromide, 4-acetylbromobenzene, quan-
titatively gave the coupling product in both solvents H2O/
iPrOH and H2O (Table 3, entry 7). Only poor yields were
obtained with inactive aryl chloride as substrate (Table 3,
entry 8).
Synthesis of glucose-based ligand, N-salicylidene-
D-glucosamine
Recently, Khalafi-Nezhad and coworkers [6, 33] repor-
ted the immobilizing of the palladium nanoparticles on
silica-starch substrate (PNP–SSS) and its use for the Heck
and Suzuki reactions in water medium. The catalytic
results, including those for Heck and Suzuki couplings are
comparable to those reported in this paper. The advantage
of our catalytic system in comparison with that published
by Khalafi-Nezhad is simple catalyst preparation. How-
ever, the method described here involves non-reusability of
catalyst as a disadvantage.
Ligand N-salicylidene-D-glucosamine (Sal-D-glsmN) was
prepared in a similar manner according to the reported
procedure with some modification [10]. To a MeOH sus-
pension (20 mL) of glucosamine hydrochloride (0.5 g,
2.32 mmol), finely grinded-solid NaOH (0.1 g, 2.55 mmol)
was added in a single portion. The mixture was stirred at
room temperature, and after 30 min NaCl was filtered off.
Salicylaldehyde (2.55 mmol, 0.27 mL) was slowly added
to the filtrate, and the reaction mixture was stirred for 2 h at
35 °C. The solution was then concentrated in vacuum
to 5 mL and put into an ice bath, the yellow solid filtered
off, washed with cooled methanol, and then dried under
vacuum. Yield 420 mg(64 %). 1H NMR(d6-DMSO):
d 8.21 (t, 1 H), 7.22 (m, 1H,), 7.10 (m, 1H), 6.68 (m, 1H),
6.59 (m, 1H,), 3.10-3.83 (multiple peaks, 7H); elemental
Conclusion
In conclusion, we have developed an efficient and environ-
mentally friendly water-soluble glucose-based ligand, which
is readily accessible from inexpensive and commercial
123

J IRAN CHEM SOC
6. A. Khalafi-Nezhad, F. Panahi, J. Organom, J. Organom. Chem.
717, 141 (2012)
7. N. Miyaura, Cross-coupling reactions (Springer, Berlin, 2002)
8. Q. Du, W. Zhang, H. Ma, J. Zheng, B. Zhou, Y. Li, Tetrahedron
68, 3577 (2012)
analysis calcd for C13H17NO6 (283.11): C 55.12, H 6.05, N
4.94; found C 55.05, H 5.97, N 5.01.
General procedure for the Suzuki reactions
9. S. Mohanty, D. Suresh, M.S. Balakrishna, J.T. Mague, Tetrahe-
dron 64, 240 (2008)
10. X.Q. Zhang, Y.P. Qiu, B. Rao, M.M. Luo, Organometallics 28,
3093 (2009)
11. B.P. Morgan, G.A. Galdamez, R.J. Gilliard Jr, R.C. Smith, Dalton
Trans. 2009, 2020 (2009)
12. Y.B. Zhou, Z.X. Xi, W.Z. Chen, D.Q. Wang, Organometallics 27,
5911 (2008)
13. J. Broggi, H. Clavier, P. Nolan, Organometallics 27, 5525 (2008)
14. O. Diebolt, P. Braunstein, S.P. Nolan, C.S.J. Cazin, Chem.
Commun. 2008, 3190 (2008)
15. N.T.S. Phan, M.V.D. Sluys, C.W. Jones, Adv. Synth. Catal. 348,
609 (2006)
All Suzuki reactions were carried out without an inert
atmosphere. A mixture of aryl halide (1.0 mmol), arylbo-
ronic acid (1.2 mmol), KOH (2 mmol), Pd(OAc)2
(0.5 mol %), and ligand Sal-D-glsmN (1 mol %) in H2O
(3 mL) or (3:1) mixture of H2O/iPrOH (3 mL) was allowed
to react in a sealed tube at 85 °C. The reaction mixtures
was added to brine (15 mL) and extracted three times with
diethyl ether (3 9 15 mL). The combined organic phase
was analyzed by GC. The further purification of the
product was achieved by flash chromatography on a silica
gel column using hexane/ethyl acetate (5:1).
16. N.G. Andersen, B.A. Keay, Chem. Rev. 101, 997 (2001)
17. R. Martin, S.L. Buchwald, Acc. Chem. Res. 41, 1461 (2008)
´
18. S. Woodward, M. Dieguez, O. Pamies, Coord. Chem. Rev. 254,
`
2007 (2010)
´
´
20. M. Dieguez, O. Pamies, A. Ruiz, Y. Diaz, S. Castillon, C. Claver,
General procedure for the Heck reactions
`
`
19. M. Dieguez, O. Pamies, C. Claver, Chem. Rev. 104, 3189 (2004)
´
All Heck reactions were carried out under air. A mixture of
aryl halide (1.0 mmol), olefins (1.2 mmol), K2CO3
(2 mmol), Pd(OAc)2 (1 mol %), and ligand Sal-D-glsmN
(2 mol %) in (2:1) mixture of H2O/iPrOH or H2O/DMF
(3 mL) was allowed to react in a sealed tube at 80 °C. The
reaction mixtures were added to brine (15 mL) and extracted
three times with diethyl ether (3 9 15 mL). The combined
organic phase was analyzed by GC. The further purification
of the product was achieved by flash chromatography on a
silica gel column using hexane/ethyl acetate (5:1).
Coord. Chem. Rev. 248, 2165 (2004)
´
21. M. Dieguez, A. Ruiz, C.Claver, Dalton Trans. 2003, 2957 (2003)
22. J.C. Pessoa, I. Tomaz, R.T. Henriques, Inorg. Chim. Acta 356,
121 (2003)
23. C. Liu, Q. Ni, P. Hu, J. Qiu, Org. Biomol. Chem. 9, 1054 (2011)
´
24. N.F. Churruca, R. SanMartin, I. Tellitu, E. Domınguez, Synlett
20, 3116 (2005)
¨
25. M. Qadir, T. Mochel, K.K. Hii, Tetrahedron 56, 7975 (2000)
26. M.L. Kantam, M. Annapurna, P.R. Likhar, P. Srinivas, N. Mir-
zadeh, S.K. Bhargava, J. Organomet. Chem. 723, 129 (2013)
27. M. Trived, G. Singh, R. Nagarajan, N.P. Rath, Inorg. Chim. Acta
394, 107 (2013)
28. M. Aydemir, A. Baysal, E. Sahin, B. Gumguma, S. Ozkar, Inorg.
Chim. Acta 378, 10 (2011)
Acknowledgments Authors thank the Research Council of Sharif
University of Technology and University of Maragheh for financial
support of this work.
29. M. Bagherzadeh, M. Amini, A. Ellern, L.K. Woo, Inorg. Chim.
Acta 383, 46 (2012)
30. F. Coccia, L. Tonucci, N. d’Alessandro, P. D’Ambrosio, M.
Bressan et al., Inorg. Chim. Acta 399, 12 (2013)
31. R.J. Kalbasi, N. Mosaddegh, A. Abbaspourrad, Tetrahedron Lett.
53, 3763 (2012)
32. A. Landarani-Isfahani, I. Mohammadpoor-Baltork, V. Mirkhani,
A.R. Khosropour, M. Moghadam, S. Tangestaninejad, R. Kia,
Adv. Synth. Catal. 355, 957 (2013)
33. A. Khalafi-Nezhad, F. Panahi, Green Chem. 13, 2408 (2011)
34. F. Heshmatpour, R. Abazari, S. Balalaie, Tetrahedron 68, 3001
(2012)
References
1. D. Dallinger, C.O. Kappe, Chem. Rev. 107, 2563 (2007)
2. K.G. Thakur, D. Ganapathy, G. Sekar, Chem. Commun. 47, 5076
(2011)
3. R.A. Sheldon, Green Chem. 7, 267 (2005)
4. J. Tsuji, Palladium reagents and catalysts (John Wiley & Sons,
Chichester, 1995)
35. J.L. Pratihar, P. Pattanayak, D. Patra, C.-H. Lin, S. Chattopad-
hyay, Polyhedron 33, 67 (2012)
5. F. Diederich, P.J. Stang, Metal-catalyzed cross-coupling reac-
tions (Wiley-VCH, Weinheim, 1998)
123