A simple, efficient, and recyclable phosphine-free catalytic system for carbonylative suzuki coupling reaction of aryl and heteroaryl iodides

Article abstract of DOI:10.1055/s-0030-1258349

The carbonylative Suzuki cross-coupling reaction of arylboronic acid with aryl and heteroaryl iodides using polymer supported palladium-N-heterocyclic carbene complex (PS-Pd-NHC) as an efficient heterogeneous, recyclable catalyst is described. The developed catalytic system is found to be effective for the carbonylative coupling reaction of aryl, heteroaryl, and bicyclic heteroaryl iodides (5-iodoindole and 3-iodoquinoline) with various arylboronic acid derivatives providing good to excellent yields of the desired products. The protocol is advantageous due to the ease in handling of the catalyst and simple workup procedure, and environmentally benign with effective catalyst recyclability. Georg Thieme Verlag Stuttgart - New York.

Full text of DOI:10.1055/s-0030-1258349

PAPER
243
A Simple, Efficient, and Recyclable Phosphine-Free Catalytic System for
Carbonylative Suzuki Coupling Reaction of Aryl and Heteroaryl Iodides
Recyclable
C
ata
i
lyst fo
y
Carbonylat
a
S
uzuki
udaction din S. Qureshi, Krishna M. Deshmukh, Pawan J. Tambade, Bhalchandra M. Bhanage*
Department of Chemistry, Institute of Chemical Technology (Autonomous), N. Parekh Marg, Matunga, Mumbai 400 019, India
Fax +91(22)24145614; E-mail: bhalchandra_bhanage@yahoo.com; E-mail: bm.bhanage@ictmumbai.edu.in
Received 11 October 2010; revised 28 October 2010
tive binding ability to transition metals irrespective of
their oxidation states. N-Heterocyclic carbene ligands re-
veal a very high dissociation energy as compared to phos-
phine ligand, which have been quantified via theoretical
Abstract: The carbonylative Suzuki cross-coupling reaction of
arylboronic acid with aryl and heteroaryl iodides using polymer
supported palladium–N-heterocyclic carbene complex (PS-Pd-
NHC) as an efficient heterogeneous, recyclable catalyst is de-
scribed. The developed catalytic system is found to be effective for calculation for different metals.12 Therefore, the binding
the carbonylative coupling reaction of aryl, heteroaryl, and bicyclic
between the NHC and transition metal is much stronger,
heteroaryl iodides (5-iodoindole and 3-iodoquinoline) with various
and chemically and thermally more inert towards cleav-
arylboronic acid derivatives providing good to excellent yields of
age than that of other complexes. The NHC ligands can be
the desired products. The protocol is advantageous due to the ease
bound to the polymer and explored for catalysis; as such
in handling of the catalyst and simple workup procedure, and envi-
polymer-supported catalysts offers various advantages
such as reuse of expensive transition metals and ligands
with a possibility to prevent the contamination of ligand
residue in products. Various groups have studied the ap-
plication of polymer supported palladium–NHC complex
as a catalyst for Suzuki coupling reactions.13
ronmentally benign with effective catalyst recyclability.
Key words: biaryl ketones, boron, heterogeneous catalysis, palla-
dium, Suzuki carbonylation
Biaryl ketones are important building blocks in the syn-
thesis of several natural products and pharmaceutical
compounds.1 They are usually prepared by Friedel–Crafts
acylation of substituted aromatic compounds.2 The major
disadvantage of traditional Friedel–Crafts acylation is the
use of excessive amount of Lewis acid and limiting regi-
oselectivity towards para-position. Other described meth-
ods for the synthesis of biaryl ketones involves transition-
metal-mediated, three component cross-coupling reaction
between arylmetal reagents, carbon monoxide, and aryl
electrophiles.3–9 These carbonylative reactions have limi-
tation due to the formation of biaryl side products without
carbon monoxide insertion particularly with electron-
deficient aryl halides.10
In continuation of our interest on phosphine-free carbon-
ylation reactions,14 herein we report an facile protocol for
the carbonylative Suzuki coupling reaction of arylboronic
acid with aryl and heteroaryl iodides using polymer-
supported palladium–NHC complex (PS-Pd-NHC) as a
heterogeneous and recyclable catalyst for the first time
(Scheme 1).
Initially, carbonylative Suzuki coupling reaction of iodo-
benzene with phenylboronic acid in the presence of (PS-
Pd-NHC) complex was chosen as a model reaction, and
the influence of various reaction parameters such as sol-
vent, base, temperature, pressure, catalyst loading, and re-
action time was investigated. It was observed that the
nature of solvent affects the selectivity of the reaction.
The reaction was found to work efficiently in nonpolar
solvents as compared to the polar solvents. In polar apro-
Recently, N-heterocyclic carbene (NHC) has gained con-
siderable attention as an effective ligand for transition
metals in homogeneous catalysis,11 because of their effec-
I
O
Pd
B(OH)2
AcO
OAc
Me
N
N
PS-Pd-NHC
CO
I
O
n( )
X
PS-Pd-NHC
n
X
X = N, S; n = 1, 2
Scheme 1 Carbonylative Suzuki coupling reaction of arylboronic acid with aryl and hetroaryl iodides
SYNTHESIS 2011, No. 2, pp 0243–0250
x
x
.
x
x
.2
0
1
1
Advanced online publication: 03.12.2010
DOI: 10.1055/s-0030-1258349; Art ID: P15410SS
© Georg Thieme Verlag Stuttgart · New York

244
Z. S. Qureshi et al.
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tic solvents such as 1,4-dioxane (34%), THF (42%), and carbonylative cross coupling reaction of sterically hin-
DMF (50%) low yield of the product was observed. Non- dered 2-iodotoluene and 2-iodoanisole with phenylboron-
polar solvents like toluene (94%) and diisopropyl ether ic acid gives good yield (88–90%) of the respective
(85%) were found to be highly effective providing excel- products (Table 1, entries 2, 3). The reaction of 4-iodotol-
lent yield of carbonylated product. However, in the case uene and 4-iodoanisole proceeded smoothly with slightly
of anisole, 40% yield of the desired product was observed. higher yields of corresponding carbonylated products
A polar protic solvent such as water was also found to give (Table 1, entries 4, 5). The reaction of electron-rich 2-io-
good yield (70%) of benzophenone. Further, we studied doaniline with phenylboronic acid yields 2-aminoben-
the effect of various bases like K3PO4, Cs2CO3, and Et3N zophenone in excellent amount (93%, Table 1, entry 6).
on reaction outcome, wherein K2CO3 was found to the The reaction of aryl iodide bearing strong electron-with-
best base giving an excellent yield of 94% for the expect- drawing groups such as COMe and NO2 also permits the
ed product. It was also observed that the reaction did not carbonylative coupling reaction with phenylboronic acid
proceed in the absence of base. In the case of temperature giving 4-acetylbenzophenone (95%) and 4-nitrobenzo-
study, with decrease in the reaction temperature from phenone (91%) in excellent yields respectively (Table 1,
100 to 80 °C, decrease in the yield (65%) of desired prod- entries 7, 8). The carbonylation of bulky 1-iodonaphtha-
uct was observed. The other reaction parameters like in- lene with phenylboronic acid offers 89% of benzoylnaph-
fluence of CO pressure, catalyst loading, and reaction thalene (Table 1, entry 9). Interestingly 1,2-diiodobenzene
time were also studied, and the optimum reaction condi- under optimized reaction conditions provides selective
tions for carbonylative Suzuki coupling reaction of iodo- monocarbonylated product (2-iodobenzophenone) with
benzene with phenylboronic acid were found to be PS-Pd- phenylboronic acid in moderate yield (Table 1, entry 10).
NHC (50 mg, 14.5 mmol), toluene as solvent, K2CO3 as
base, and 100 psi of CO pressure, at 100 °C for 10 hours.
The effect of substituents on the phenylboronic acid was
then investigated, and it was observed that both electron-
These optimized reaction conditions were then used for donating and electron-withdrawing groups were well tol-
cabonylative Suzuki cross-coupling reaction of various erated under present reaction conditions. Electron-donat-
aryl iodides with different arylboronic acids providing ing groups like Me and OMe at ortho- and para-position
good to excellent yields of the desired products (Table 1, of boronic acid provides good to excellent yield of the cor-
entries 1–15). Various electron-donating and electron- responding ketones (Table 1, entries 11–14). The present
withdrawing groups such as Me, OMe, NH2, COMe, NO2, catalytic system also works well with the electron-defi-
and Br on both aryl iodide and arylboronic acid smoothly cient 4-bromophenylboronic acid, providing 85% of 4-
underwent carbonylative Suzuki coupling reaction giving bromobenzophenone (Table 1, entry 15). In general, the
desired products with appreciable yields.
yield of the carbonylative cross coupling product for sub-
stituted boronic acids were lower than the corresponding
substituted aryl iodides.
Iodobenzene reacts smoothly with phenylboronic acid
giving 94% yield of benzophenone (Table 1, entry 1). The
Table 1 Carbonylative Suzuki Coupling Reaction of Aryl Iodides with Various Arylboronic Acidsa
Entry
Aryl iodide
Boronic acid
Product
Yield (%)b
94
O
O
O
I
B(OH)2
1
I
B(OH)2
B(OH)2
B(OH)2
2
3
4
90
88
90
MeO
I
MeO
O
I
O
I
B(OH)2
5
91
MeO
MeO
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Recyclable Catalyst for Carbonylative Suzuki Coupling Reaction
245
Table 1 Carbonylative Suzuki Coupling Reaction of Aryl Iodides with Various Arylboronic Acidsa (continued)
Entry
6
Aryl iodide
Boronic acid
Product
Yield (%)b
NH2
O
I
B(OH)2
93
95
91
NH2
O
O
I
B(OH)2
B(OH)2
7
8
O
O
I
O2N
O2N
I
O
B(OH)2
9
89
I
I
O
O
O
O
O
B(OH)2
B(OH)2
I
10
11
12
13
14
31
80
79
82
88
I
I
I
I
OMe
OMe
B(OH)2
B(OH)2
B(OH)2
MeO
OMe
Br
O
B(OH)2
I
15
85
Br
a Reaction conditions: aryl iodide (1 mmol), arylboronic acid (1.2 mmol), PS-Pd-NHC (14.5 mmol), K2CO3 (3 mmol), toluene (10 mL), 100 °C,
CO (100 psi), 10 h.
b Isolated yield.
Moreover, the generality of our catalytic system (PS-Pd- The carbonylative Suzuki coupling reaction of 2-iodopy-
NHC) was explored by coupling different arylboronic ridine and 3-iodopyridine with phenylboronic acid using
acids with heteroaryl iodides such as 2-iodopyridine, 3- PS-Pd-NHC complex as a catalyst provides 89% and 91%
iodopyridine, 2-iodothiophene, 5-iodoindole, and 3-iodo- yield, respectively, of the desired products (Table 2, en-
quinoline in toluene as a solvent and 200 psi CO pressure. tries 1, 2). The reaction of sterically hindered electron-rich
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Z. S. Qureshi et al.
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arylboronic acids such as 2-methylphenylboronic acid (Table 2, entry 5). The reaction of 2-iodothiophene with
and 2-methoxyphenylboronic acid with 3-iodopyridine 2-methylphenylboronic acid, 2-methoxyphenylboronic
offer products in admirable yields (90–93%,Table 2, en- acid and 3-methylphenylboronic acid provided respective
tries 3, 4). However, 4-bromophenylboronic acid gave diaryl ketones in 82, 68, and 98% yield, respectively
moderate yield of the product with 3-iodopyridine (Table 2, entry 6–8).
Table 2 Carbonylative Suzuki Coupling Reaction of Hetetoaryl Iodides with Various Arylboronic Acidsa
Entry
Aryl iodide
Boronic acid
Product
Yield (%)b
89
O
O
B(OH)2
N
1
N
N
N
N
I
I
B(OH)2
B(OH)2
2
3
4
91
90
93
N
N
N
O
O
O
I
I
I
OMe
B(OH)2
OMe
B(OH)2
5
6
7
8
70
82
68
98
N
S
Br
N
S
Br
B(OH)2
I
O
O
O
B(OH)2
OMe
S
S
I
I
S
S
OMe
B(OH)2
O
O
O
I
I
I
B(OH)2
9
10
11
93
94
90
N
H
N
H
B(OH)2
N
H
MeO
N
H
OMe
B(OH)2
N
H
Br
N
H
Br
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Recyclable Catalyst for Carbonylative Suzuki Coupling Reaction
247
Table 2 Carbonylative Suzuki Coupling Reaction of Hetetoaryl Iodides with Various Arylboronic Acidsa (continued)
Entry
12
Aryl iodide
Boronic acid
Product
Yield (%)b
95
O
O
I
I
B(OH)2
N
N
N
B(OH)2
13
98
N
a Reaction conditions: aryl iodide (1 mmol), arylboronic acid (1.2 mmol), PS-Pd-NHC (14.5 mmol), K2CO3 (3 mmol), toluene (10 mL), 100 °C,
CO (100 psi), 10 h.
b Isolated yield.
Encouraged with these results, the PS-Pd-NHC complex for consecutive four cycles with maintenance of high ac-
was then subjected for carbonylative Suzuki coupling re- tivity and selectivity (Table 3). No significant decrease in
actions of 5-iodoindole and 3-iodoquinoline with various yield during the three recycles was observed; however,
arylboronic acids. To the best of our knowledge, there is yield declined up to 86% for the fourth cycle. This de-
no general method reported for the synthesis of sterically crease in yield might be due to handling loss of complex
hindered heteroaryl ketones from iodoindole and io- during the study.
doquinoline through carbonylative Suzuki cross coupling
reaction. It was noticed that 5-iodoindole smoothly under-
Table 3 Recyclability Study of PS-Pd-NHC Complex Catalysta
goes carbonylative coupling reaction with phenylboronic
acid, providing 93% yield of heterobiaryl ketone (Table 2,
entry 9). Electron-donating and electron-withdrawing
groups such as OMe and Br on phenylboronic acid were
well tolerated to give the desired biaryl ketone in good to
excellent yields (Table 2, entries 10, 11). The reaction of
3-iodoquinoline with phenylboronic acid, provides the de-
sired carbonylative Suzuki coupling product in 95% yield
(Table 2, entry 12). Reaction of 3-methylphenylboronic
acid with 3-iodoquinoline underwent smoothly with ex-
cellent yield of quinolin-3-yl-m-tolylmethanone (Table 2,
entry 13).
Entry
PS-Pd-NHC catalyst
fresh
Yield (%)b
1
2
3
4
5
94
94
93
92
86
recycle 1
recycle 2
recycle 3
recycle 4
a Reaction conditions: iodobenzene (1 mmol), phenylboronic acid
(1.2 mmol), PS-Pd-NHC (50 mg, 14.5 mmol), K2CO3 (3 mmol), tolu-
ene (10 mL), 100 °C, CO (100 psi), 10 h.
b GC yield.
In order to determine whether the catalysis was due to the
PS-Pd-NHC complex or due to a homogeneous palladium
complex that comes off the support during the reaction
and returns back to the support at the end, we performed a
hot filtration test.15 The carbonylative cross coupling reac-
tion of iodobenzene with phenylboronic acid was carried
out at 100 °C. Then PS-Pd-NHC complex was filtered off
after two hours of reaction time and the filtrate was al-
lowed to react further. The catalyst filtration was per-
formed at 100 °C in order to avoid possible recoordination
of soluble palladium upon cooling. We found that, after
this hot filtration, no further reaction occurred. This ex-
perimental finding suggests that the palladium metal did
not leach out of complex at elevated temperature during
the progress of reaction. In addition, to reconfirm this ob-
servation ICP-AES analysis of the reaction mixture was
carried out after 2 hours and after 10 hours, which re-
vealed below detectable level (below 0.01 ppm) of palla-
dium in solution.
In conclusion, an efficient phosphine-free protocol for the
carbonylative Suzuki coupling reaction of aryl and het-
eroaryl iodides using PS-Pd-NHC complex as a heteroge-
neous and recyclable catalyst has been developed. The
reaction was optimized with respect to various parameters
and enabled carbonylative Suzuki coupling reaction of
different aryl and heteroaryl iodides with variety of aryl-
boronic acids affording good to excellent yield of desired
products thus illustrating broad application of the method-
ology. Further, the PS-Pd-NHC complex was recycled for
consecutive four cycles without any significant loss in cat-
alytic activity.
All chemicals and reagents were procured from commercial suppli-
ers and used without further purification. The products were char-
1
acterized using H NMR, 13C NMR spectra (Varian Mercury 300
NMR Spectrometer) and IR (Perkin-Elmer FT-IR) spectroscopic
techniques. The reactions progress was monitored via GC (Perkin-
Elmer, Clarus 400) (BP-10 GC column, 30 m × 0.32 mm ID, film
thickness 0.25 mm). Products were confirmed by GC-MS
(Shimadzu GC-MS QP 2010). Polymer-supported Pd-N-hetero-
To make the synthetic protocol more economical, it is
necessary to study the recyclability of PS-Pd-NHC com-
plex. The PS-Pd-NHC catalyst was found to be recycled
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248
Z. S. Qureshi et al.
PAPER
cyclic carbene complex (PS-Pd-NHC) used was prepared according
to the procedure reported in the literature.13a Elemental analysis
confirms that about 0.29 mmol/g of Pd catalyst was loaded on (chlo-
romethyl)polystyrene resin support. Petroleum ether (PE) used re-
fers to the fraction boiling in the range 60–80 °C.
IR (KBr): 2920, 2852, 1689, 1657, 1593, 1445, 1402, 1358, 1277,
1072, 963, 931, 845, 795, 698 cm–1.
1H NMR (300 MHz, CDCl3): d = 2.66 (s, 3 H), 7.52–7.47 (t, J = 7.5
Hz, 1 H), 7.65–7.59 (t, J = 8.8 Hz, 1 H), 7.82–7.79 (d, J = 8.4 Hz, 2
H), 7.88–7.87 (d, J = 8.4 Hz, 2 H), 8.07–8.04 (d, J = 8.8 Hz, 2 H).
13C NMR (75.43 MHz, CDCl3): d = 197.5 (C=O), 195.9 (C=O),
141.4 (C), 139.6 (C), 137.0 (C), 133.0 (CH), 130.11 (2 CH), 130.05
(2 CH), 128.5 (2 CH), 128.2 (2 CH), 22.7 (CH3).
Carbonylative Suzuki Coupling Reaction of Aryl Iodides with
Arylboronic Acid; General Procedure
To a 100 mL autoclave were added aryl iodide (1.0 mmol), arylbo-
ronic acid (1.2 mmol), PS-Pd-NHC (50 mg, 14.5 mmol), toluene (10
mL), and K2CO3 (415 mg, 3.0 mmol). The mixture was first stirred
for 10 min and then flushed with CO, then filled with 100 psi of CO,
and the reaction mixture was heated at 100 °C for 10 h. After com-
pletion of the reaction, the mixture was cooled to r.t. The catalyst
was filtered off and the solvent was removed under reduced pres-
sure. The residue obtained was purified by column chromatography
(silica gel, 60–120 mesh; PE–EtOAc, 90:10) to afford the desired
carbonylated product (Table 1). The structures of the products were
MS (EI, 70 eV): m/z (%) = 224 (53), 209 (100), 181 (10), 147 (35),
105 (80), 77 (78), 43 (35).
2-Iodobenzophenone (Table 1, entry 10)
Yield: 95 mg (31%); solid.
IR (KBr): 3059, 2922, 2852, 1743, 1669, 1595, 1580, 1448, 1314,
1285, 1251, 1194, 1157, 1078, 1015, 927, 799, 762, 703, 954 cm–1.
1H NMR (300 MHz, CDCl3): d = 7.31–7.17 (m, 1 H), 7.50–7.41 (m,
3 H), 7.62–7.55 (m, 2 H), 7.81–7.78 (d, J = 8.4 Hz, 1 H), 7.93–7.9
(d, J = 8.1 Hz, 2 H).
13C NMR (75.43 MHz, CDCl3): d = 197.2 (C=O), 144.7 (C), 139.8
(C), 135.7 (CH), 133.7 (CH), 132.4 (CH), 131.2 (CH), 130.5 (2
CH), 128.7 (2 CH), 127.8 (CH), 92.3 (C).
1
confirmed by GC-MS, H NMR, 13C NMR, and IR spectroscopic
techniques. The purity of compounds was determined by GC-MS
analysis.
Carbonylative Suzuki Coupling Reaction of Heteroaryl Iodides
with Arylboronic Acid; General Procedure
MS (EI, 70 eV): m/z (%) = 308 (10), 231 (28), 203 (10), 181 (18),
152 (23), 105 (100), 77 (76), 45 (71).
To a 100 mL autoclave were added heteroaryl iodide (1.0 mmol),
arylboronic acid (1.2 mmol), PS-Pd-NHC (50 mg, 14.5 mmol), tol-
uene (10 mL), and K2CO3 (415 mg, 3.0 mmol). The reaction mix-
ture was first stirred for 10 min and then flushed with CO, then filled
with 200 psi of CO and the mixture was heated at 100 °C for 10–15
h. After completion of the reaction, the mixture was cooled to r.t.
The catalyst was filtered off and the solvent was removed under re-
duced pressure. The residue obtained was purified by column chro-
matography (silica gel, 60–120 mesh; PE–EtOAc, 90:10) to afford
the desired carbonylated product (Table 2). The structure of the
Pyridin-3-yl-o-tolylmethanone (Table 2, entry 3)
Yield: 177 mg (90%); solid.
IR (KBr): 2925, 2851, 1729, 1670, 1584, 1463, 1292, 1270, 1190,
1081, 1025, 966, 925, 796, 737, 650 cm–1.
1H NMR (300 MHz, CDCl3): d = 2.38 (s, 3 H), 7.46–7.26 (m, 5 H),
8.16–8.14 (d, J = 8.1 Hz, 1 H), 8.81–8.79 (d, J = 6.2 Hz, 1 H), 8.93
(s, 1 H).
13C NMR (75.43 MHz, CDCl3): d = 196.8 (C=O), 153.1 (CH),
151.3 (CH), 147.1 (C), 137.3 (CH), 133.4 (C), 131.5 (C), 131.1
(CH), 129.0 (CH), 125.5 (CH), 123.6 (CH), 119.0 (CH), 14.1 (CH3).
1
products were confirmed by GC-MS, H NMR, 13C NMR, and IR
spectroscopic techniques. The purity of compounds was determined
by GC-MS analysis.
Recycling of PS-Pd-NHC Complex for Carbonylative Suzuki
Coupling Reaction of Iodobenzene with Phenylboronic Acid
After completion of reaction, the reaction mixture was cooled to r.t.,
and the catalyst was collected by filtration. The filtered catalyst was
washed vigorously with distilled H2O (5 × 10 mL), MeOH (5 × 10
mL), and dried under reduced pressure. The dried catalyst was then
used for catalyst recyclability experiment. It was observed that the
recovered catalyst could be reused for four consecutive cycles for
the carbonylative Suzuki coupling reaction of iodobenzene with
phenylboronic acid (94%, 94%, 93%, 92%, 86%, respectively).
MS (EI, 70 eV): m/z (%) = 196 (100), 197 (45), 182 (5), 168 (34),
141 (5), 119 (51), 106 (11), 91 (75), 89 (22), 78 (30), 65 (41), 51
(31), 45 (34).
(2-Methoxyphenyl)pyridin-3-ylmethanone (Table 2, entry 4)
Yield: 198 mg (93%); solid.
IR (KBr): 2922, 2852, 1667, 1599, 1487, 1464, 1300, 1246, 1162,
1111, 1023, 927, 827, 756, 713, 648 cm–1.
1H NMR (300 MHz, CDCl3): d = 3.69 (s, 3 H), 7.02–6.99 (d, J = 8.4
Hz, 1 H), 7.10–7.05 (dd, J = 7.3, 7.69 Hz, 1 H), 7.54–7.38 (m, 3 H),
8.14–8.11 (d, J = 8.1 Hz, 1 H), 8.75–8.73 (d, J = 6.6 Hz, 1 H), 8.91
(s, 1 H).
13C NMR (75.43 MHz, CDCl3): d = 194.9 (C=O), 157.5 (C), 152.8
(CH), 151.1 (CH), 136.6 (CH), 133.4 (C), 133.0 (CH), 130.1 (CH),
127.5 (CH), 123.3 (CH), 120.9 (C), 111.4 (CH), 55.4 (CH3).
Characterization of Selected Compounds
2-Aminobenzphenone (Table 1, entry 6)
Yield: 183 mg (93%); solid.
IR (KBr): 3436, 3318, 3054, 2934, 1626, 1589, 1553, 1479, 1449,
1328, 1303, 1250, 1151, 1025, 938, 912, 745, 703, 645 cm–1.
1H NMR (300 MHz, CDCl3): d = 6.1 (br, 2 H), 6.61–6.55 (t, J = 7.9
Hz, 1 H), 6.73–6.70 (d, J = 8 Hz, 1 H), 7.3–7.24 (m, 2 H), 7.46–7.42
(t, J = 5.9 Hz, 1 H), 7.51–7.49 (d, J = 7.3 Hz, 2 H), 7.64–7.61 (d,
J = 8.1 Hz, 2 H).
MS (EI, 70 eV): m/z (%) = 213 (30), 182 (4), 135 (100), 107 (11),
92 (25), 77 (51), 64 (11), 51 (32), 45 (29).
Thiophen-2-yl-o-tolylmethanone (Table 2, entry 6)
Yield: 165 mg (82%); solid.
13C NMR (75.43 MHz, CDCl3): d = 199.1 (C=O) 151.0 (C), 140.2
(C), 134.6 (CH), 134.2 (CH), 131.0 (CH), 129.1 (2 CH), 128.1 (2
CH), 118.0 (CH), 117.0 (CH), 115.5 (CH).
IR (KBr): 3449, 2962, 1641, 1513, 1411, 1354, 1297, 1262, 1097,
1047, 848, 795, 733 cm–1.
1H NMR (300 MHz, CDCl3): d = 2.38 (s, 3 H), 7.12–7.11 (dd,
J = 3.66, 4.0 Hz, 1 H), 7.30–7.25 (m, 2 H), 7.45–7.36 (m, 2 H),
7.71–7.70 (d, J = 1.1 Hz, 1 H), 7.73–7.72 (d, J = 1.1 Hz, 1 H).
MS (EI, 70 eV): m/z (%) = 197 (100), 120 (41), 105 (16), 92 (31),
77 (44), 65 (36), 51 (19).
4-Acetylbenzophenone (Table 1, entry 7)
Yield: 212 mg (95%); solid.
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Recyclable Catalyst for Carbonylative Suzuki Coupling Reaction
249
13C NMR (75.43 MHz, CDCl3): d = 190.5 (C=O), 145.0 (C), 138.5
(C), 136.5 (C), 135.5 (CH), 134.9 (CH), 131.1 (CH), 130.4 (CH),
128.1 (CH), 125.2 (CH), 14.2 (CH3).
MS-MS (ESI+): m/z calcd for (M + 1): 252.09; found (M + 1):
252.1.
(4-Bromophenyl)(1H-indol-5-yl)methanone (Table 2, entry 11)
Yield: 270 mg (90%); solid.
MS (EI, 70 eV): m/z (%) = 202 (100), 187 (5), 169 (28), 141 (24),
128 (10), 119 (15), 111 (59), 91 (47), 83 (13), 65 (34), 45 (14).
IR (KBr): 3269, 1644, 1595, 1429, 1329, 1284, 1203, 1330, 1284,
1203, 1100, 1067, 1011, 977, 878, 841, 773, 754, 729 cm–1.
(2-Methoxyphenyl)thiophen-2-yl-methanone (Table 2, entry 7)
Yield: 148 mg (68%); solid.
1H NMR (300 MHz, CDCl3): d = 6.65 (d, J = 2.2 Hz, 1 H), 7.30–
7.26 (d, J = 12.46 Hz, 1 H), 7.47–7.44 (d, J = 8.8 Hz, 2 H), 7.70–
7.67 (d, J = 8.4 Hz, 2 H), 7.77–7.73 (d, J = 9.9 Hz, 2 H), 8.09 (s, 1
H), 8.60 (br, 1 H).
13C NMR (75.43 MHz, CDCl3): d = 196.3 (C=O), 138.5 (C), 137.8
(C), 131.6 (2 CH), 131.5 (2 CH), 129.5 (C), 127.3 (C), 126.6 (C),
125.6 (CH), 125.2 (CH), 124.2 (CH), 111.2 (CH), 104.4 (CH).
IR (KBr): 3359, 2923, 2851, 1644, 1599, 1459, 1411, 1354, 1264,
1163, 1108, 1050, 1023, 884, 844, 757, 643 cm–1.
1H NMR (300 MHz, CDCl3): d = 3.78 (s, 3 H), 6.95–6.92 (d, J = 8.4
Hz, 1 H), 7.10–6.98 (m, 2 H), 7.46–7.38 (dd, J = 4.4, 7.3 Hz, 1 H),
7.66 (d, J = 1.1 Hz, 1 H), 7.85 (d, J = 1.83 Hz, 1 H), 7.87 (d,
J = 1.46 Hz, 1 H).
13C NMR (75.43 MHz, CDCl3): d = 188.2 (C=O), 164.5 (C), 144.9
(C), 135.2 (CH), 134.6 (CH), 132.9 (CH), 131.9 (CH), 129.2 (CH),
121.2 (CH), 120.2 (C), 111.6 (CH), 55.7 (CH3).
MS-MS (ESI+): m/z calcd for (M + 1): 299.99; found (M + 1):
300.0.
Phenylquinolin-3-yl-methanone (Table 2, entry 12)
Yield: 234 mg (95%); solid.
MS (EI, 70 eV): m/z (%) = 218 (62), 201 (23), 185 (73), 173 (21),
135 (65), 121 (63), 111 (100), 105 (20), 92 (35), 77 (65), 45 (15).
IR (KBr): 3052, 2924, 2853, 1649, 1598, 1572, 1493, 1445, 1367,
1290, 1245, 1178, 1122, 935, 911, 860, 759, 726, 698, 595 cm–1.
Thiophen-2-yl-m-tolylmethanone (Table 2, entry 8)
Yield: 197 mg (98%); solid.
1H NMR (300 MHz, CDCl3): d = 7.55 (m, 3 H), 7.67–7.5 (dd,
J = 7.7, 8.1 Hz, 1 H), 7.87–7.80 (m, 2 H), 7.92–7.89 (d, J = 8.1 Hz,
2 H), 8.20–8.18 (d, J = 8.43 Hz, 1 H), 8.53 (s, 1 H), 9.33 (s, 1 H).
IR (KBr): 3391, 3100, 2921, 1633, 1513, 1412, 1353, 1289, 1209,
1123, 1052, 931, 861, 776, 735, 652 cm–1.
1H NMR (300 MHz, CDCl3): d = 2.41 (s, 3 H), 7.15–7.14 (dd,
J = 4.03, 3.66 Hz, 1 H), 7.37–7.32 (m, 2 H), 7.66–7.62 (m, 3 H),
7.70–7.68 (d, J = 4.8 Hz, 1 H).
13C NMR (75.43 MHz, CDCl3): d = 194.8 (C=O), 150.3 (CH),
149.4 (C), 138.8 (CH), 137.0 (C), 133.1 (CH), 131.9 (CH), 130.0 (2
CH), 129.4 (C), 129.2 (C), 128.6 (3 CH), 127.6 (CH), 126.6 (CH).
13C NMR (75.43 MHz, CDCl3): d = 188.4 (C=O), 156.4 (CH),
143.5 (C), 138.2 (CH), 137.9 (CH), 134.9 (C), 134.2 (CH), 133.0
(CH), 129.5 (CH), 128.1 (CH), 126.3 (CH), 21.2 (CH3).
MS (EI, 70 eV): m/z (%) = 233 (100), 204 (12), 176 (3), 156 (29),
128 (50), 105 (66), 77 (78), 45 (89).
Quinolin-3-yl-m-tolylmethanone (Table 2, entry 13)
Yield: 242 mg (98%); solid.
MS (EI, 70 eV): m/z (%) = 202 (68), 187 (25), 174 (4), 141 (3), 119
(48), 111 (100), 91 (40), 83 (10), 65 (26), 45 (15).
IR (KBr): 3057, 2917, 1656, 1617, 1596, 1495, 1415, 1368, 1292,
1189, 1039, 788, 758, 588 cm–1.
(1H-Indol-5-yl)phenylmethanone (Table 2, entry 9)
Yield: 205 mg (93%); solid.
1H NMR (300 MHz, CDCl3): d = 2.42 (s, 3 H), 7.45–7.38 (m, 2 H),
7.67–7.60 (dd, J = 7.3, 7.0 Hz, 1 H), 7.95–7.81 (m, 4 H), 8.23–8.20
(d, J = 8.8 Hz, 1 H), 8.56 (s, 1 H), 9.31 (s, 1 H),
IR (KBr): 3292, 2923, 2851, 1621, 1607, 1572, 1431, 1322, 1116,
1092, 957, 880, 734 cm–1.
1H NMR (300 MHz, CDCl3): d = 6.62 (d, J = 2.2 Hz, 1 H), 7.27–
7.26 (dd, J = 2.56, 2.93 Hz, 1 H), 7.45–7.44 (m, 3 H), 7.50–7.47 (d,
J = 8.06 Hz, 1 H), 7.57–7.55 (d, J = 7.3 Hz, 1 H), 7.83–7.77 (dd,
J = 6.96, 8.8 Hz, 2 H), 8.13 (s, 1 H), 8.93 (br, 1 H).
13C NMR (75.43 MHz, CDCl3): d = 194.8 (C=O), 149.9 (CH),
148.9 (C), 138.9 (C), 138.7 (CH), 138.4 (CH), 134.6 (C), 133.8
(CH), 131.8 (CH), 130.9 (C), 130.2 (CH), 130.0 (C), 129.1 (CH),
128.3 (CH), 127.5 (CH), 126.5 (CH), 21.1 (CH3).
13C NMR (75.43 MHz, CDCl3): d = 197.0 (C=O), 139.0 (C), 138.5
(C), 131.8 (CH), 123.0 (2 CH), 129.6 (C), 128.2 (2 CH), 127.2 (C),
126.0 (CH), 125.4 (CH), 124.2 (CH), 111.2 (CH), 104.1 (CH).
MS (EI, 70 eV): m/z (%) = 247 (100), 232 (81), 218 (7), 204 (6), 156
(30), 128 (57), 119 (78), 101 (40), 91 (75), 75 (19), 65 (34), 51 (14),
45 (27).
MS-MS (ESI+): m/z calcd for (M + 1): 222.08; found (M + 1):
222.1.
Acknowledgment
(1H-Indol-5-yl)(4-methoxyphenyl)methanone (Table 2, entry
10)
The financial assistance from Indira Gandhi Centre for Atomic Re-
search (IGCAR), Kalpakkam, India is kindly acknowledged.
Yield: 235 mg (94%); solid.
IR (KBr): 3262, 2929, 2840, 1624, 1508, 1420, 1308, 1252, 1175,
1116, 1093, 1029, 964, 885, 849, 823, 760, 731, 614, 576 cm–1.
References
1H NMR (300 MHz, CDCl3): d = 3.88 (s, 3 H), 6.60 (d, J = 2.2 Hz,
1 H), 6.98–6.95 (d, J = 8.8 Hz, 2 H), 7.26–7.25 (d, J = 2.6 Hz, 1 H),
7.42–7.40 (d, J = 8.4 Hz, 1 H), 7.73–7.70 (d, J = 7 Hz, 1 H), 7.86–
7.83 (d, J = 8.8 Hz, 2 H), 8.10 (s, 1 H), 8.90 (br, 1 H).
13C NMR (75.43 MHz, CDCl3): d = 196.7 (C=O), 162.8 (C), 138.2
(C), 132.6 (2CH), 131.4 (C), 130.2 (C), 127.2 (C), 125.9 (CH),
124.9 (CH), 124.1 (CH), 113.6 (CH), 113.4 (CH), 111.1 (CH),
104.2 (CH), 55.5 (CH3).
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