PVC-supported palladium nanoparticles: An efficient catalyst for suzuki cross-coupling reactions at room temperature

Article abstract of DOI:10.1055/s-0033-1338293

A simple and efficient protocol is described for a Suzuki reaction catalyzed by poly(vinyl chloride)-supported nanoparticles of metallic palladium at room temperature. Aryl iodides, bromides, and chlorides underwent smooth Suzuki reactions in aqueous ethanol, an environmentally friendly solvent, under ligand-free conditions to give good yields of the desired biaryl products. The heterogeneous catalyst could be used up to four times with no detectable metal leaching or loss of catalytic efficiency. Georg Thieme Verlag Stuttgart.New York.

Full text of DOI:10.1055/s-0033-1338293

PAPER
▌1201
pPapVerC-Supported Palladium Nanoparticles: An Efficient Catalyst for Suzuki
Cross-Coupling Reactions at Room Temperature
Efficient Catalyst for Suzuki Cross-Coupling Reactions
Mamidi Samarasimhareddy, Girish Prabhu, Thimmalapura M. Vishwanatha, Vommina V. Sureshbabu*
#
109, Peptide Research Laboratory, Department of Studies in Chemistry, Central College Campus, Bangalore University,
Dr. B. R. Ambedkar Veedhi, Bangalore 560 001, India
Fax +91(80)22292848; E-mail: sureshbabuvommina@rediffmail.com; E-mail: hariccb@gmail.com; E-mail: hariccb@hotmail.com
Received: 08.12.2012; Accepted after revision: 08.03.2013
mobilization of the metal on a matrix eliminates problems
Abstract: A simple and efficient protocol is described for a Suzuki
associated with agglomeration, metal contamination, and
reaction catalyzed by poly(vinyl chloride)-supported nanoparticles
leaching of the metal, and it permits ready recycling of the
and chlorides underwent smooth Suzuki reactions in aqueous etha- catalyst. Supported palladium nanoparticles are increas-
of metallic palladium at room temperature. Aryl iodides, bromides,
8
nol, an environmentally friendly solvent, under ligand-free condi- ingly used in various reactions, such as hydrogenations,
9
tions to give good yields of the desired biaryl products. The aerobic oxidations, and cross-coupling reactions. Reetz
heterogeneous catalyst could be used up to four times with no de-
tectable metal leaching or loss of catalytic efficiency.
10
and co-workers reported the application of palladium
11
nanoparticles in cross-coupling reactions. Das et al. re-
Key words: coupling reactions, supported catalysis, palladium, ha-
lides, biaryls, Suzuki reactions
ported the use of palladium nanoparticles supported on
borohydride-exchanged resin beads or microparticles for
the synthesis of biaryl compounds through a ligand-free
Suzuki reaction at 110 °C for six to twelve hours. Sayed
1
2
Palladium-catalyzed cross-coupling reactions are indis-
used nanoparticles of poly(1-vinylpyr-
and co-workers
pensable tools for the construction of C–C bonds in syn- rolidone)-supported palladium in a ligand-free Suzuki re-
theses of fine chemicals, pharmaceuticals, advanced action under reflux conditions for twelve hours.
1
functional materials, and natural products. Among these Pd(0)/polypyrrole nanoparticles have been used in a
reactions, the Suzuki–Miyaura cross-coupling reaction is
widely used in the construction of biaryl and heterobiaryl
Suzuki reaction at a high temperature (100 °C) for six
Palladium(0) nanoparticles supported on diphe-
compounds from aryl or hetaryl halides or triflates and ar- nylphosphinylated silica gel have also been used as a cat-
ylboronic acids or their esters. The Suzuki reaction has alyst for the Suzuki reaction. However, the high reaction
continued to garner attention because of the many appli- temperatures, long reaction times, and limited substrate
cations that result from its tolerance toward a wide range scope have limited the use of such reactions, and there is
of functional groups and because of the stability, low tox- still considerable interest in developing readily prepared
icity, and commercial availability of boronic acid and bo- and versatile catalysts to permit efficient syntheses of bi-
ronate ester reactants. The Suzuki reaction has been used aryl and heterobiaryl compounds.
1
3
hours.
2
14
on an industrial scale for the synthesis of the sartan family
Poly(vinyl chloride) (PVC) is a widely used, commercial-
ly available, inexpensive polymer. Catalysts consisting of
3
of hypertensive drugs and the fungicide boscalid. Vari-
ous modifications, such as new catalysts, new ligands, and
even ligand-free conditions, have been developed during
palladium(0) nanoparticles supported on 2-aminoethanol-
1
5
16
modified PVC or a PVC-derived Schiff base have been
used in Heck and Suzuki reactions. Our group has report-
ed the preparation of palladium nanoparticles supported
on unmodified PVC, and we have demonstrated their use
in the reduction of a range of functional groups, as well as
in the deprotection of some common protecting groups in
the past two decades to render the Suzuki reaction simple,
mild, and efficient.4
The chemistry of metal nanoparticles has emerged as an
interesting field with a wide range of applications in syn-
5
thesis and in medicine. The small size and high surface
1
7
area of metal nanoparticles renders them useful in cataly-
In continuation of our interest in met-
peptide chemistry.
sis. Limitations on the use of palladium complexes, such al nanoparticle-catalyzed reactions, we examined the use
as high costs, metal contamination, laborious reaction of unmodified PVC-supported palladium nanoparticles in
conditions, and problems with recycling of catalysts has ligand-free Suzuki cross-coupling reactions at room tem-
led to the development of supported palladium nanoparti- perature.
6
cles as catalysts. Various supports have been explored,
including porous materials, ionic liquids, surfactants, den-
The Pd(0)/PVC catalyst was freshly prepared in a single
batch that was used in all the subsequent reactions. Induc-
tively coupled plasma–optical emission spectroscopy
drimers, functionalized polymers, biopolymers, various
7
ligands, and silica (in supercritical carbon dioxide). Im-
(
ICP–OES) analysis of the catalyst showed that its palla-
dium content was 13% (for transmission electron micro-
graphs and a histogram, see the Supporting Information).
Initially, we examined the Suzuki reaction of 0.1 mmol of
iodobenzene (1a) with 0.12 mmol of phenylboronic acid
SYNTHESIS 2013, 45, 1201–1206
Advanced online publication:
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0
3
9
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8
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1
1
4
3
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DOI: 10.1055/s-0033-1338293; Art ID: SS-2012-N0948-OP
Georg Thieme Verlag Stuttgart · New York
©

1202
M. Samarasimhareddy et al.
PAPER
(2a) as model substrates in the presence of 0.815 mg of various aryl iodides or bromides 1 with various boronic
Pd(0)/PVC catalyst (0.106 mg of Pd) under air. In prelim- acids 2.
inary experiments, we tested sodium carbonate and cesi-
In a typical reaction, phenylboronic acid (2a; 0.12 mmol),
um carbonate as bases, and we performed the reaction at
room temperature in a 1:1 mixture of 1,2-dimethoxy-
ethane and water as the solvent. Only traces of biphenyl
sodium carbonate (0.2 mmol), and Pd(0)/PVC (0.106 mg
of Pd) were added to a solution of iodobenzene (1a; 0.1
mmol) in 1:1 ethanol–water, and the mixture was stirred
at room temperature for two hours while we monitored the
course of the reaction by thin-layer chromatography. The
pure product was isolated by simple workup without any
column purification in this case. Under our optimized re-
action conditions, the Suzuki reaction proceeded smooth-
ly in two to three hours with various aryl halides 1 and
arylboronic acids 2 bearing electron-rich or electron-defi-
cient functional groups (Table 2). In most cases, the Suzu-
ki product 3 was isolated after removal of the catalyst by
filtration without the need for any column purification.
The ortho-substituted reactant 1-iodo-2-methoxybenzene
gave a slightly lower yield of the corresponding biphenyl
(3a) were obtained in either case (Table 1, entries 1 and 2).
Increasing the temperature to 85 °C led to slight increases
in the yield of biphenyl (entries 3 and 4). Other common
solvents, such as 1,4-dioxane, acetonitrile, or N,N-dimeth-
ylformamide, in 1:1 mixtures with water were also exam-
ined in the presence of sodium carbonate or cesium
carbonate. Yields of the product in all the cases were un-
satisfactory (<35%), even at high temperatures (entries 5–
10). Finally, to our delight the use of a 1:1 mixture of eth-
anol and water as the solvent with sodium carbonate as the
base resulted in efficient ligand-free synthesis of biphenyl
(3a) from iodobenzene (1a) and phenylboronic acid (2a)
at room temperature catalyzed by Pd(0)/PVC (Table 1,
entry 12).
3c (entry 3).
Table 2 Synthesis of Biaryls 3 from Aryl Bromides or Iodides with
Pd(0)/PVC Catalyst at Room Temperature
Table 1 Screening of Solvents and Bases for the Suzuki–Miyaura
Reaction of Iodobenzene with Phenylboronic Acid
R2
X
B(OH)2
Solventa
Base
Temp Time Yield (%)
Pd(0)/PVC, Na2CO3
Entry
+
(°C)
(h)
of 3a
EtOH–H2O, r.t., 2–3 h
R1
X = Br, I
R2
R1
1
2
3
4
5
6
7
8
9
DME–H O
Na CO
25
25
80
85
85
85
87
87
74
74
r.t.
r.t.
10
10
6
10
8
2
2
3
3
3
3
3
DME–H O
Cs CO
3
Entry
Aryl halide
R2
Product
Yield (%)
2
2
DME–H O
Na CO
28
20
26
18
32
27
23
16
83
99
2
2
1
PhI
H
3a
3b
3c
3d
3e
3f
99
97
93
97
96
98
98
99
97
98
DME–H O
Cs CO
5
2
2
3
2
PhI
4-F C
3
1,4-dioxane–H O Na CO
6
2
2
3
2-MeOC H I
H
6
4
1,4-dioxane–H O Cs CO
5
2
2
3
4
4-BnC H Br
H
6
4
DMF–H O
Na CO
7
2
2
5
4-H NC H Br
H
2
6
4
DMF–H O
Cs CO
7
2
2
3
6
PhI
4-pyridyl
4-F
MeCN–H O
Na CO
6
2
2
7
PhBr
PhBr
3g
3h
3i
1
1
0
1
2
1
MeCN–H O
Cs CO
6
2
2
3
8
4-Me
EtOH–H O
Cs CO
2
2
2
3
9
4-MeOC H Br 4-MeO
6 4
1
EtOH–H O
Na CO
2
2
2
3
10
4-O NC H Br
4-F
3j
2
6
4
a
:1 mixture.
We then turned our attention to the catalytic activity of
Pd(0)/PVC for the reaction of aryl chlorides with arylbo-
ronic acids. Activation of aryl chlorides is much more
sluggish than that of the analogous bromo or iodo com-
pounds. For this reason, Suzuki reactions of aryl chlorides
have been effected by using sterically demanding elec-
tron-rich ligands, which are often sensitive to air or mois-
ture and which frequently require multistep syntheses.
The sensitivity and expense of these ligands led to inves-
tigate the use of ligand-free catalytic systems for the
Next, we examined the effect of the catalyst loading on
the reaction of phenylboronic acid (2a) and iodobenzene
(1a). A catalyst loading of 0.407 mg of Pd(0)/PVC in a
0
.1-mmol-scale reaction resulted in a 95% yield of biphe-
nyl (3a) in four hours, whereas the reaction was found to
be complete in two hours with a 99% yield at a loading of
18
0
1
.815 mg Pd(0)/PVC. Increasing the catalyst loading to
.22 mg had no beneficial effect on the yield or rate of the
reaction.
19
Suzuki cross-coupling reactions of aryl chlorides.
1
9d
We therefore selected an optimal catalyst loading of 0.815 Diaconescu and co-workers reported the use of palladi-
mg Pd(0)/PVC for the 0.1-mmol-scale Suzuki reactions of um(0) nanoparticles supported on polyaniline nanofibers
Synthesis 2013, 45, 1201–1206
© Georg Thieme Verlag Stuttgart · New York

PAPER
Efficient Catalyst for Suzuki Cross-Coupling Reactions
1203
as active catalysts for the coupling of aryl chlorides in wa- Table 3 Suzuki Cross-Coupling Reaction of Aryl Chlorides with
Arylboronic Acids at Room Temperature with Pd(0)/PVC Catalyst
ter at 80–100 °C for two to six hours. Liu and co-
workers1 reported a ligand-free Suzuki reaction of aryl
9a
R2
chlorides catalyzed by palladium nanoparticles generated
X
B(OH)2
2
0
Pd(0)/PVC, Na CO3
2
in situ. Li and co-workers reported a ligand-free Suzuki
coupling reaction of aryl chlorides on the presence of
magnetically separable iron(III) sulfate/silica-supported
palladium(0) nanoparticles at 130 °C for 36 hours.
+
EtOH–H2O, r.t., 4–6 h
R1
X = Cl
R2
R1
R2
Product Yield%
2
1
Entry
Aryl chloride
Choudary et al. reported the use of double-layer hydrox-
ide-supported palladium nanoparticles for the Suzuki re-
action of aryl chlorides at 100 °C for ten hours. The
majority of these reported protocols therefore require
harsh reaction conditions and long reaction times.
1
2
3
4
5
6
7
8
9
4-TolCl
H
3h
3k
3l
97
90
87
94
95
91
95
89
92
90
91
94
2-H NC H Cl
H
2
6
4
2-chlorothiophene
3-MeO CC H Cl
H
We examined the coupling of 4-chlorotoluene with
phenylboronic acid under similar conditions to those that
we employed for the coupling of iodides or bromides at
room temperature. Interestingly, the reaction was found to
be complete within 4.5 hours at room temperature, and the
desired biaryl compound 3h was obtained in excellent
yield (97%). Furthermore, when we subjected a series of
activated and nonactivated aryl chlorides to the Suzuki re-
action, all the desired biaryl compounds were isolated in
good yields within four to six hours (Table 3). In case of
H
3m
3n
3o
3p
3q
3r
3s
2
6
4
4-NCC H Cl
H
6
4
4-H NC H Cl
4-Me
H
2
6
4
4-O NC H Cl
2
6
4
4-HO CC H Cl
4-OMe
4-NO2
H
2
6
4
3-MeOC H Cl
6
4
1
1
1
0
1
2
4-HCOC H Cl
6 4
2-chlorothiophene, a slight decrease in the yield was no-
ticed (entry 3). Also, the reaction was slower with the non-
activated chlorides, although the desired biaryls were still
obtained in good yields after six hours (entries 2, 6, and 8).
Aryl chlorides with electron-withdrawing substituents
showed higher reactivities and gave better yields when of
the products (entries 4, 5, and 7) than did those with elec-
tron-donating substituents.
4-MeCOC H Cl
H
3t
6
4
3-MeOC H Cl
H
3u
6
4
Table 4 Recycling of the Catalyst System
We tested the recyclability of the catalyst for the reaction
between iodobenzene (1a) and phenylboronic acid (2a).
When the reaction was complete, the catalyst was recov-
ered by filtration, washed successively with water and
ethanol, dried, and reused directly in the next cycle. The recycle 1
catalyst performed well when recycled up to three times,
and the reaction was found to be complete within 2–2.3
hours with a consistent yield (Table 4). The palladium recycle 3
content of the recycled catalyst after the third round of re-
Cycle
fresh
Time (h)
Yield (%) of 3a
2
99
97
98
96
90
2
recycle 2
2
2.3
3
recycle 4
cycling was found to be 12.7% by ICP–OES. This indicat-
ed negligible leaching of the active nanopalladium species
during three recycling operations (0.3% in total). Howev-
er, the efficiency of the nanocatalyst fell after a fourth methods, including mild reaction conditions, a faster and
round of recycling, and its palladium content (ICP-OES) cleaner reaction profile, and superior yields.
fell markedly to 11.81%, indicating that considerable
leaching of the catalytic species had occurred. These stud-
ies confirmed that Pd(0)/PVC nanoparticles can act as an
PVC powder (low molecular weight: Mw 48,000, K value 55–57;
density: 1.4 g/mL at 25 °C) was purchased from Sigma-Aldrich and
efficient and recyclable catalyst system for the Suzuki re- used directly. ICP–OES measurements were made on PerkinElmer
Optima 5300 DV equipment. Melting points were recorded on a
action under mild conditions.
1
Thomas–Hoover capillary apparatus and are uncorrected. H and
In conclusion, the Pd(0)/PVC catalyst was successfully
13
C NMR spectra were recorded with a Brucker FT NMR Avance-
used in ligand-free Suzuki cross-coupling reactions of 300 spectrometer at 300 and 75 MHz, respectively. Chemical shifts
aryl iodides, bromides, or chlorides at room temperature. (δ) are reported relative to TMS as an internal standard. High-
resolution mass spectra were recorded on a Micromass Q-TOF
The catalyst can be easily separated from the reaction
mixture by simple filtration, and it can be reused up to
spectrometer operated in the ESI mode.
three times without any significant loss of activity. Our
Pd(0)/PVC Catalyst
(600 mg, 3.38 mmol) was added to a suspension of PVC pow-
der (2.4 g) in EtOH (440 mL). The mixture was stirred for 2 h then
present protocol offers several advantages over reported PdCl
2
©
Georg Thieme Verlag Stuttgart · New York
Synthesis 2013, 45, 1201–1206

1204
M. Samarasimhareddy et al.
PAPER
refluxed for 5 min while a soln of NaBH (148 mg, 4 mmol) in
4-Phenylpyridine (3f)
4
EtOH (8 mL) was slowly added. The brownish mixture immediate-
ly became colorless, indicating reduction of the Pd(II) salt to Pd(0).
The suspension was then allowed to cool before the black precipi-
White solid; yield: 15.19 mg (98%); mp 70–72 °C.
1
H NMR (300 MHz, CDCl ): δ = 7.16 (m, 1 H), 7.26–7.30 (m, 2 H),
3
7.40–7.46 (m, 2 H), 7.49–7.56 (m, 2 H), 8.21 (m, 2 H).
tate was collected by filtration. Excess NaBH was quenched with
4
13
C NMR (75 MHz, CDCl ): δ = 121.32, 126.84, 128.92, 129.16,
H O and the black powder of Pd(0)/PVC was washed successively
3
2
1
38.45, 147.17, 149.46.
with MeOH and H O then dried under vacuum.
2
HRMS: m/z [M + Na]+ calcd for C H NNa: 178.0633; found:
1
1
9
Biaryls (3a–v); General Procedure
1
78.0620.
Pd(0)/PVC (0.815 mg; 0.106 mg Pd) was added to a stirred soln of
the appropriate aryl halide (0.1 mmol), arylboronic acid (0.12
mmol), and Na CO (0.2 mmol) in 1:1 EtOH–H O (4 mL), and the
4
-Fluorobiphenyl (3g)
2
3
2
White solid; yield: 16.86 mg (98%); mp 77–80 °C.
mixture was stirred at r.t. until the reaction was complete (TLC).
The mixture was then filtered and the residue was washed with
EtOH (3 mL). The solvent was evaporated under vacuum and the
residue was extracted with EtOAc (2 ×5 mL). The separated organic
layer was washed with brine (5 mL), dried (Na SO ), and concen-
trated under vacuum. Where necessary, the product was purified by
column chromatography (silica gel 100–200 mesh) using EtOAc–n-
hexane (1–8% EtOAc) as eluent.
1
H NMR (300 MHz, CDCl ): δ = 7.10–7.18 (m, 2 H), 7.27–7.68 (m,
H).
3
7
13C NMR (75 MHz, CDCl
128.6, 128.71, 128.79, 137.31, 137.35, 137.95, 164.09.
HRMS: m/z [M + Na]+ calcd for C H FNa: 195.0586; found:
1
): δ = 115.43, 115.72, 126.99, 127.23,
3
2
4
12
9
95.0589.
4
-Methylbiphenyl (3h)
Biphenyl (3a)
White solid; yield: 16.64 mg (99%) from PhBr and 4-TolB(OH)2,
White solid; yield: 15.4 mg (99%); mp 68–70 °C.
16.30 mg (97%) from 4-TolCl and PhB(OH) ; mp 44–46 °C.
2
1
H NMR (300 MHz, CDCl ): δ = 7.2–7.8 (m, 7 H), 8.21–8.37 (m, 3
1
3
H NMR (300 MHz, CDCl ): δ = 2.39 (s, 3 H), 7.30 (d, J = 7.8 Hz,
3
H).
2
H), 7.36–7.47 (m, 1 H), 7.57–7.60 (m, 2 H), 7.70 (d, J = 8.0 Hz,
13
C NMR (75 MHz, CDCl ): δ = 127.90, 132.67, 133.43, 135.62.
2 H), 7.78–7.80 (m, 2 H).
3
HRMS: m/z [M + Na]+ calcd for C H Na: 177.0680; found:
13C NMR (75 MHz, CDCl
138.14, 141.2.
): δ = 21.07, 126.91, 129.4 (4 C), 136.93,
3
1
2
10
177.0683.
HRMS: m/z [M + Na]+ calcd for C H Na: 191.0837; found:
1
3
12
4
-(Trifluoromethyl)biphenyl (3b)
1
91.0842.
White solid; yield: 21.53 mg (97%); mp 69–72 °C
1
H NMR (300 MHz, CDCl ): δ = 7.38 (t, J = 7.2 Hz, 1 H), 7.43 (t,
4,4′-Dimethoxybiphenyl (3i)
3
J = 7 Hz, 2 H), 7.54 (d, J = 6.8 Hz, 2 H), 7.62 (s, 4 H).
White solid; yield: 20.76 mg (97%); mp 178–181 °C.
1H NMR (300 MHz, CDCl
): δ = 3.86 (s, 6 H), 6.94 (d, J = 7.2 Hz,
4 H), 7.46 (d, J = 7.4 Hz, 4 H).
13
C NMR (75 MHz, CDCl ): δ = 123.63, 124.82, 127.35, 127.46,
3
3
128.37, 129.12, 129.49, 136.13, 139.67.
HRMS: m/z [M + Na]+ calcd for C H F Na: 245.0554; found:
13C NMR (75 MHz, CDCl
158.62.
): δ = 55.32, 114.18, 127.72, 133.41,
13
9 3
3
245.0531.
+
HRMS: m/z [M + Na] calcd for C H NaO : 237.0891; found:
1
4
14
2
2
-Methoxybiphenyl (3c)
2
37.0897.
Colorless gummy liquid; yield: 17.12 mg (93%).
1
H NMR (300 MHz, CDCl ): δ = 3.82 (s, 3 H), 6.94–6.98 (m, 2 H),
4-Fluoro-4′-nitrobiphenyl (3j)
3
7
.25–7.30 (m, 3 H), 7.35–7.39 (m, 2 H), 7.48–7.51 (m, 2 H).
White solid; yield: 21.27 mg (98%); mp 120–123 °C.
1H NMR (300 MHz, CDCl
): δ = 7.16–7.19 (m, 2 H), 7.60–7.63 (m,
2 H), 7.67 (d, J = 8.4 Hz, 2 H), 8.26 (d, J = 8.2 Hz, 2 H).
13C NMR (75 MHz, CDCl
): δ = 116.42, 121.26, 128.31, 129.14,
13
C NMR (75 MHz, CDCl ): δ = 55.45, 11.20, 120.75, 126.84,
3
3
127.91, 128.53, 129.42, 130.63, 130.76, 138.53, 156.41.
HRMS: m/z [M + Na]+ calcd for C H NaO: 207.0786; found:
1
3
12
3
207.0782.
131.83, 141.92, 147.26, 161.38.
+
HRMS: m/z [M + Na] calcd for C H FNNaO : 240.0437; found:
1
2
8
2
4
-(Benzyloxy)biphenyl (3d)
2
40.0441.
Light-yellow solid; yield: 25.23 mg (97%); mp 298–300 °C.
1
H NMR (300 MHz, CDCl ): δ = 5.18 (s, 2 H), 7.12–7.18 (m, 2 H),
Biphenyl-2-amine (3k)
3
7
.30–7.70 (m, 12 H).
White solid; yield: 15.21 mg (90%); mp 48–50 °C.
1H NMR (300 MHz, CDCl
): δ = 3.68 (br s, 2 H), 6.70 (d, J = 8.2
Hz, 1 H), 6.78 (t, J = 7.2 Hz, 1 H), 7.08–7.13 (m, 2 H), 7.29 (m, 1
13
C NMR (75 MHz, CDCl ): δ = 71.3, 114.3, 127.1, 127.4, 126.9,
3
3
127.6, 128.2, 128.6, 128.7, 128.8, 136.1, 139.6, 159.2.
H), 7.37–7.42 (m, 4 H).
HRMS: m/z [M + Na]+ calcd for C H NaO: 283.1099; found:
1
9
16
13C NMR (75 MHz, CDCl
28.5, 129.1, 130.2, 139.4, 143.1.
): δ = 115.2, 118.4, 127.3, 127.6, 128.2,
3
283.110.
1
Biphenyl-4-amine (3e)
Yellowish brown solid; yield: 16.23 mg (96%); mp 50–53 °C.
HRMS: m/z [M + Na]+ calcd for C H NNa: 192.0789; found:
1
2
11
1
92.0792.
1
H NMR (300 MHz, CDCl ): δ = 13.6–3.8 (br s, 2 H), 6.76–6.80 (m,
3
2
H), 7.20–7.35 (m, 1 H), 7.41–7.50 (m, 4 H), 7.56–7.60 (m, 2 H).
2-Phenylthiophene (3l)
White solid; yield: 13.92 mg (87%); mp 33–35 °C.
1H NMR (300 MHz, CDCl
): δ = 7.05–7.12 (m, 1 H), 7.24–7.40 (m,
H), 7.62–7.71 (m, 2 H).
13C NMR (75 MHz, CDCl
27.95, 128.84, 134.40, 144.42.
13
C NMR (75 MHz, CDCl ): δ = 115.33, 126.19, 126.33, 127.94,
3
128.59, 131.52, 141.10, 145.77.
3
5
HRMS: m/z [M + Na]+ calcd for C H NNa: 192.0789; found:
1
2
11
192.0786.
): δ = 123.04, 124.76, 125.94, 127.42,
3
1
Synthesis 2013, 45, 1201–1206
© Georg Thieme Verlag Stuttgart · New York

PAPER
Efficient Catalyst for Suzuki Cross-Coupling Reactions
1205
HRMS: m/z [M + Na]+ calcd for C H NaS: 183.0244; found:
13
C NMR (75 MHz, CDCl ): δ = 127.34, 127.66, 128.21, 128.84,
1
0
8
3
183.0251.
129.67, 135.48, 136.15, 141.63, 191.21.
HRMS: m/z [M + Na]+ calcd for C H NaO: 205.0629; found:
1
3
10
Methyl Biphenyl-3-carboxylate (3m)
White solid; yield: 19.93 mg (94%); mp 116–118 °C.
2
05.0631.
1
H NMR (300 MHz, CDCl ): δ = 3.86 (s, 3 H), 7.28–7.57 (m, 4 H),
.60–7.62 (m, 3 H), 7.71–7.79 (m, 1 H), 8.01–8.13 (m, 1 H).
1-Biphenyl-4-ylethanone (3t)
White solid; yield: 17.84 mg (91%); mp 119–122 °C.
3
7
13
1
C NMR (75 MHz, CDCl ): δ = 52.13, 127.08, 127.67, 128.19,
H NMR (300 MHz, CDCl ): δ = 2.68 (s, 3 H), 7.41–7.53 (m, 3 H),
3
3
128.28, 128.81, 130.60, 131.46, 140.02, 141.38, 166.99.
7.62–7.71 (m, 4 H), 8.03–8.06 (d, J = 7 Hz, 2 H).
+
13
HRMS: m/z [M + Na] calcd for C H NaO : 235.0735; found:
C NMR (75 MHz, CDCl ): δ = 26.72, 127.26, 127.35, 127.42,
1
4
12
2
3
235.0741.
128.64, 128.92, 135.86, 139.90, 145.73, 197.7.
HRMS: m/z [M + Na]+ calcd for C H NaO: 219.0786; found:
1
4
12
Biphenyl-4-carbonitrile (3n)
White solid; yield: 17.01 mg (95%); mp 83–85 °C.
2
19.0789.
1
H NMR (300 MHz, CDCl ): δ = 7.42 (t, J = 7.2 Hz, 1 H), 7.48 (t,
3-Methoxybiphenyl (3u)
White solid; yield: 17.30 mg (94%); mp 87–90 °C.
3
J = 7.6 Hz, 2 H), 7.62 (d, J = 7.4 Hz, 2 H), 7.70–7.72 (m, 4 H).
13
1
C NMR (75 MHz, CDCl ): δ = 110.62, 118.65, 127.26, 127.43,
H NMR (300 MHz, CDCl ): δ = 3.86 (s, 3 H), 7.05–7.07 (m, 2 H),
3
3
128.47, 129.04, 132.67, 139.21, 145.66.
7.25–7.60 (m, 7 H).
HRMS: m/z [M + Na]+ calcd for C H NNa: 202.0633; found:
13
C NMR (75 MHz, CDCl ): δ = 55.31, 114.18, 126.62, 126.70,
1
3
9
3
202.0637.
128.11, 128.68, 133.76, 140.80, 159.13.
HRMS: m/z [M + Na]+ calcd for C H NaO: 207.0786; found:
1
3
12
(
4′-Methylbiphenyl-4-yl)amine (3o)
2
07.0789.
Yellowish brown solid; yield: 16.66 mg (91%); mp 92–95 °C.
1
H NMR (300 MHz, CDCl ): δ = 2.38 (s, 3 H), 3.67 (br s, 2 H), 6.72
3
(
d, J = 8.4 Hz, 2 H), 7.16–7.20 (m, 2 H), 7.35–7.41 (m, 4 H).
Acknowledgment
13
C NMR (75 MHz, CDCl ): δ = 21.02, 115.44, 126.25, 127.53,
3
We sincerely thank the Department of Science and Technology-
Nano Mission (Grant No. SR/NM/NS-13/2007) for financial sup-
port. We also thank Dr. S. Kotha, IIT, Bombay, for performing the
transmission electron microscopy analyses.
1
29.27, 131.64, 135.27, 138.42, 145.38.
HRMS: m/z [M + Na]+ calcd for C H NNa: 206.0946; found:
1
3
13
206.0957.
4
-Nitrobiphenyl (3p)
White solid; yield: 18.91 mg (95%); mp 110–112 °C.
Supporting Information for this article is available online at
1
H NMR (300 MHz, CDCl ): δ = 7.40–7.51 (m, 3 H), 7.61 (d, J = 7
http://www.thieme-connect.com/ejournals/toc/synthesis. Included
3
1
13
Hz, 2 H), 7.72 (d, J = 8.6 Hz, 2 H), 8.24 (d, J = 8.4 Hz, 2 H).
are TEM and histogram data for PVC-Pd(0) and H and C NMR
13
spectra and HRMS spectra for selected compounds.SunogIopiftrmanSrtnuIpgrfoi
p
m
nirtat
C NMR (75 MHz, CDCl ): δ = 124.33, 127.24, 127.56, 128.62,
3
129.37, 138.45, 146.82, 147.23.
+
HRMS: m/z [M + Na] calcd for C H NNaO : 222.0531; found: References
1
2
9
2
222.0536.
(
1) (a) Handbook of Organopalladium Chemistry for Organic
Synthesis; Negishi, E.; de Meijere, A., Eds.; Wiley: New
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O.; Colacot, T. J.; Snieckus, V. Angew. Chem. Int. Ed. 2012,
4
′-Methoxybiphenyl-4-carboxylic Acid (3q)
White solid; yield: 20.29 mg (89%); mp 263–265 °C.
1
H NMR (300 MHz, CDCl ): δ = 3.82 (s, 3 H), 6.89 (d, J = 8.4 Hz,
3
5
1, 5062.
2
H), 7.68 (d, J = 8.6 Hz, 2 H), 7.74 (d, J = 8.6 Hz, 2 H), 7.96 (d,
(2) (a) Miyaura, N.; Suzuki, A. Chem. Rev. 1995, 95, 2457.
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(
(
b) Kohei, T.; Miyaura, N. Top. Curr. Chem. 2000, 219, 1.
c) Partyka, D. V. Chem. Rev. 2011, 111, 1529. (d) Miyaura,
13
C NMR (75 MHz, CDCl ): δ = 55.32, 114.56, 126.31, 128.24,
3
128.63, 129.71, 131.45, 143.87, 159.30, 167.22.
N.; Yamada, K.; Suzuki, A. Tetrahedron Lett. 1978, 3437.
+
HRMS: m/z [M + Na] calcd for C H O Na: 251.0684; found:
(3) (a) Yang, J.; Liu, S.; Zheng, J.-F.; Zhou, J. Eur. J. Org.
Chem. 2012, 6248. (b) Glasnov, T. N.; Kappe, C. O. Adv.
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1
4
12
3
251.0678.
3
-Methoxy-4′-nitrobiphenyl (3r)
(
4) (a) Yin, L.; Liebscher, J. Chem. Rev. 2007, 107, 133.
b) Climent, M. J.; Corma, A.; Iborre, S. Chem. Rev. 2011,
111, 1072.
White solid; yield: 21.07 mg (92%); mp 84–86 °C.
(
1
H NMR (300 MHz, CDCl ): δ = 3.86 (s, 3 H), 6.86 (d, J = 8.2 Hz,
3
1
H), 7.10 (s, 1 H), 7.19 (d, J = 7.4 Hz, 1 H), 7.39 (t, J = 8.2 Hz, 1
(5) (a) Roucoux, A.; Schultz, J.; Patin, H. Chem. Rev. 2002, 102,
3757. (b) Daniel, M.-C.; Astruc, D. Chem. Rev. 2004, 104,
293. (c) Baca, A. J.; Ahn, J.-H.; Sun, Y.; Meitl, M. A.;
Menard, E.; Kim, H.-S.; Choi, W. M.; Kim, D.-H.; Huang,
Y.; Rogers, J. A. Angew. Chem. Int. Ed. 2008, 47, 5524.
H), 7.72 (d, J = 6.4 Hz, 2 H), 8.28 (d, J = 7 Hz, 2 H).
13
C NMR (75 MHz, CDCl ): δ = 56.21, 111.34, 112.85, 119.60,
3
121.32, 128.48, 130.13, 137.16, 141.81, 147.47, 159.92.
+
HRMS: m/z [M + Na] calcd for C H NNaO : 252.0637; found:
1
3
11
3
(
6) Astruc, D.; Lu, F.; Ruiz Aranzaes, J. Angew. Chem. 2005,
17, 8062.
252.0637.
1
(
7) (a) Crooks, R. M.; Zhao, M.; Sun, L.; Chechik, V.; Yeung,
L. K. Acc. Chem. Res. 2001, 34, 181. (b) Prastaro, A.; Ceci,
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Biphenyl-4-carbaldehyde (3s)
White solid; yield: 16.38 mg (90%); mp 54–56 °C.
1
H NMR (300 MHz, CDCl ): δ = 7.38 (t, J = 7.4 Hz, 1 H), 7.42 (t,
3
J = 7.2 Hz, 2 H), 7.59 (d, J = 7 Hz, 2 H), 7.71 (d, J = 8.2 Hz, 2 H),
1929. (c) Son, S. U.; Jang, Y.; Yoon, K. Y.; Kang, E.;
7.92 (d, J = 6.8 Hz, 2 H), 9.89 (s, 1 H).
©
Georg Thieme Verlag Stuttgart · New York
Synthesis 2013, 45, 1201–1206

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Synthesis 2013, 45, 1201–1206
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