Ligand-free copper oxide nanoparticle-catalyzed sonogashira coupling reaction

Article abstract of DOI:10.1055/s-0030-1260023

The catalytic Sonogashira coupling reaction of terminal alkynes and aryl halides is developed using copper(II) oxide nanoparticles as catalyst in dimethyl sulfoxide. The procedure is experimentally simple, general, efficient, and free from addition of ext

Full text of DOI:10.1055/s-0030-1260023

1792
PAPER
Ligand-Free Copper Oxide Nanoparticle-Catalyzed Sonogashira Coupling
Reaction
N
ano-CuO Catalys
u
t
for Sonogashira
CY
oupling Reactionuan,*a Haitao Zhu,a Dongbo Zhao,*b Li Zhanga
a
College of Chemistry & Chemical Engineering, Yangzhou University, Jiangsu Province 225002, P. R. of China
E-mail: yyuan@yzu.edu.cn
b
Bayer Technology & Engineering (Shanghai) Co., Ltd., F3 Area, Mu Hua Road, Shanghai Chemical Industry Park, Shanghai 201507,
P. R. of China
Fax +82(21)67120397; E-mail: tony.zhao@bayertechnology.com
Received 7 March 2011; revised 31 March 2011
action using the copper(I) oxide/triphenylphosphine cata-
lytic system, however, a rather low yield of the
Sonogashira product was given after 20 hours even in the
reaction of iodobenzene with phenylacetylene at 120 °C.3a
Li also reported the combination of the octahedral cop-
per(I) oxide nanoparticles with triphenylphosphine and
TBAB as an efficient and reusable system for the
Sonogashira-type cross-coupling reaction under solvent-
less conditions.7 Recently, the copper nanocluster-cata-
lyzed Sonogashira reaction was developed by Rothenberg
in high yields.8 From the point of economy and environ-
ment, the development of some efficient copper catalytic
systems for Sonogashira reaction of a wide range of aryl
and alkyl halides are still challenging. Herein, we wish to
demonstrate the use of a simplest copper catalyst system
for Sonogashira coupling of aryl halides and teminal
alkynes (Scheme 1).
Abstract: The catalytic Sonogashira coupling reaction of terminal
alkynes and aryl halides is developed using copper(II) oxide nano-
particles as catalyst in dimethyl sulfoxide. The procedure is experi-
mentally simple, general, efficient, and free from addition of
external cocatalysts or chelating ligands.
Key words: copper(II) oxide nanoparticles, Sonogashira coupling,
ligand-free, nano catalyst
The catalytic coupling reaction of terminal alkynes with
aryl or vinyl halides is named as Sonogashira coupling,
which is typically performed with a palladium catalyst, a
copper(I) cocatalyst, and an amine base under anhydrous
and anaerobic conditions.1 However, palladium complexes,
the most commonly used catalysts for the Sonogashira-
type cross-coupling reaction, are considerably expensive,
which limits their application in industry.1,2 Recently,
much attention has been attracted to the use of copper
complexes as the catalysts for the Sonogashira-type cross-
coupling of aryl halides with terminal alkynes.3 It was
shown that copper halides chelated by many ligands such
as triphenylphosphine,3a,b 1,10-phenanthroline,3c,d N,N-
dimethylglycine,3e ethylenediamine,3f 2-aminopyrimi-
dine-4,6-diol,3g and tertiary amines3h,i are effective cata-
lysts in Sonogashira reaction. It is known that
nanomaterials containing high surface area and reactive
morphologies have been studied as effective catalysts for
many organic syntheses due to the advantages of high
atom efficiency, simplified isolation of product, and easy
recovery and recyclability of the catalysts.4 Since the cop-
per(II) oxide nanoparticles are readily accessible, air-
stable, recyclable, and free from addition of external
chelating ligands, a couple of literature have reported the
intermolecular cross-coupling reactions of aryl iodides
with nitrogen, oxygen, sulfur, and selenide nucleophiles
using copper(II) oxide nanoparticles under ligand-free
conditions.5 However, there are few successful examples
of ligand-free copper nanoparticle-catalyzed cross
Sonogashira coupling between aryl halides and terminal
alkynes so far, except the article reported by Rothenberg.6
For instance, Miura and co-workers have reported this re-
catalyst (0.1 equiv)
base (2 equiv)
R2
R2
I
solvent, 160 °C, argon
R1
R1
Scheme 1 Ligand-free nano-CuO-catalyzed Sonogashira coupling
between aryl halides and terminal alkynes
We initiated our investigation of Sonogashira reaction be-
tween iodobenzene (1a) (1.2 equiv) and phenylacetylene
(2a) (1 equiv) using 10 mol% of copper(II) oxide nano-
particle as catalyst. The first result was quite inspiring to
note that 44% yield of 3aa was obtained when the reaction
was performed for 12 hours in the presence of 2 equiva-
lents of potassium hydroxide as base in dimethyl sulfox-
ide at 160 °C (Table 1, entry 1).9 Next, some other bases
and solvents were examined in the presence of catalytic
nano copper(II) oxide (Table 1, entries 2–5). Potassium
carbonate was shown to be the best base in dimethyl sul-
foxide giving 88% yield of the product (Table 1, entry 3),
while cesium carbonate resulted in a yield of 43% as com-
pared with potassium hydroxide (Table 1, entry 2). Other
solvents gave no marked improvement compared with
dimethyl sulfoxide when the base potassium carbonate
was kept constant. For instance, only 15% of yield was
realized when N,N-dimethylformamide was chosen as
solvent (Table 1, entry 4), although N-methyl-2-pyrrolid-
inone could afford around 84% yield (Table 1, entry 5).
SYNTHESIS 2011, No. 11, pp 1792–1798
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Advanced online publication: 05.05.2011
DOI: 10.1055/s-0030-1260023; Art ID: H04311SS
© Georg Thieme Verlag Stuttgart · New York

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Nano-CuO Catalyst for Sonogashira Coupling Reaction
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Other nano metal oxides, like nano-Fe2O3, nano-NiO, and similar with the change of nano palladium in the catalytic
nano-In2O3, could only produce trace amount of Suzuki reaction.10
Sonogashira product under the same conditions (Table 1,
Based on the above-mentioned optimal conditions, a vari-
entries 6–8). It was found that the yield of product
ety of substrates were examined in the coupling reaction
dropped when the amount of nano-CuO catalyst was de-
and the results are listed in Table 2. It was shown that al-
creased (Table 1, entries 11). Interestingly, the normal
most all the combinations of different alkynes and aryl io-
commercial granules-CuO could not catalyze this type of
dides afforded high to excellent yields of target
Sonogashira reaction well, which proves that nanoparti-
Sonogashira products. And the substrate scope for aryl io-
cles were involved in the reaction (Table 1, entries 12).
dides was wide enough for 1-iodo-3-methylbenzene or 1-
With these data in hand, the reaction temperature and mo-
iodo-4-methylbenzene, electron-efficient 1-iodo-3-meth-
lar ratio of two reactants were optimized finally. It was
oxybenzene and electron-deficient 1-iodo-4-nitrobenzene
found that lower temperatures below 160 °C significantly
as well. It was also found that satisfactory yield was ob-
reduced the yields of this reaction (Table 1, entries 9, 10).
tained using aliphatic alkyne as substrate (Table 2, entry
A high temperature of up to 160 °C is a key factor, which
20).
is required to fully excite the catalytic activity of cop-
In summary, we have developed an experimentally simple
and general procedure for the Sonogashira coupling reac-
tion of terminal alkynes with aryl halides in dimethyl sul-
foxide catalyzed by nano-CuO in excellent and high
per(II) oxide nanoparticles in the coupling reaction.
Meanwhile, the yield of product 3aa was improved up to
97% when the molar ratio between 1a and 2a was in-
creased from 1.2 to 1.5 (Table 1, entry 13). In addition, the
yields. Except for the solvent dimethyl sulfoxide and cat-
TEM analysis of the CuO nanoparticles, before and after
alytic amount of nano-CuO, no other ligands or cocata-
reactions under the condition (Table 1, entry 13) showed
lysts were required for the reaction to proceed smoothly.
that after the reaction, the morphology of CuO nanoparti-
It was thus proven that copper(II) oxide nanoparticles
cles have been changed and most CuO nanoparticles were
were effective catalyst for the Sonogashira coupling reac-
aggregated (Figure 1). This change of morphology was
tion studied.
Table 1 Optimization of Nanocatalyst, Solvent, Base, and Temperature in the Sonogashira Reaction between Iodobenzene (1a) and Phenyl-
acetylene (2a)a
catalyst, base
Ph
I
Ph
+
solvent, 160 °C, argon
1a
2a
3aa
Entry
1
Solvent
Base
Catalyst
Temp (°C)
160
Yield (%)b
DMSO
DMSO
DMSO
DMF
KOH
nano-CuO
nano-CuO
nano-CuO
nano-CuO
nano-CuO
nano-Fe2O3
nano-NiO
nano-In2O3
nano-CuO
nano-CuO
nano-CuO
CuO
44
43
88
15
84
12
10
13
11
55
42
23
97
2
Cs2CO3
K2CO3
K2CO3
K2CO3
K2CO3
K2CO3
K2CO3
K2CO3
K2CO3
K2CO3
K2CO3
K2CO3
160
3
160
4
160
5
NMP
160
6
DMSO
DMSO
DMSO
DMSO
DMSO
DMSO
DMSO
DMSO
160
7
160
8
160
9
120
10
11c
12
13d
145
160
160
nano-CuO
160
a Reaction conditions: aryl iodide (1.2 mmol), phenylacetylene (1.0 mmol), catalyst (0.1 mmol), solvent (2 mL), base (2 mmol), 160 °C, 12 h
under argon.
b Isolated yield.
c Nano-CuO, 0.05 mmol.
d Aryl iodide (1.5 mmol), phenylacetylene (1.0 mmol).
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Figure 1 TEM images of (a) commercial CuO nanoparticles from Sigma-Aldrich and (b) CuO nanoparticles after the reaction
Table 2 Combinatorial Synthesis of Unsymmetric Diaryl-Substituted Ethyne via Efficient Sonogashira Coupling Reaction Catalyzed by Cop-
per(II) Oxide Nanoparticlesa
nano-CuO, K2CO3
R2
I
R2
DMSO, 160 °C, argon
R1
R1
Entry
Aryl iodide
Alkyne
Product
Yield (%)b
97
1
2
I
96
97
74
I
3
4
5
I
MeO
MeO
I
MeO
MeO
78
I
6
7
80
91
O2N
I
O2N
I
8
9
95
99
95
I
I
10
MeO
I
MeO
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Table 2 Combinatorial Synthesis of Unsymmetric Diaryl-Substituted Ethyne via Efficient Sonogashira Coupling Reaction Catalyzed by Cop-
per(II) Oxide Nanoparticlesa (continued)
nano-CuO, K2CO3
R2
I
R2
DMSO, 160 °C, argon
R1
R1
Entry
Aryl iodide
Alkyne
Product
Yield (%)b
90
MeO
MeO
11
12
13
I
72
77
O2N
I
O2N
Cl
Cl
I
Cl
Cl
Cl
Cl
Cl
Cl
14
15
16
17
18
75
95
65
86
60
I
Cl
I
Cl
MeO
MeO
I
MeO
MeO
Cl
I
Cl
O2N
I
O2N
I
19
20
82
88
I
a Reaction conditions: aryl iodide (1.5 mmol), phenylacetylene (1.0 mmol), nano-CuO (0.1 mmol), DMSO (2 mL), K2CO3 (2 mmol), 160 °C,
12 h under argon.
b Isolated yield.
1H NMR and 13C NMR spectra were obtained with a Bruker
AVANCE 600 spectrometer in CDCl3 with TMS as an internal stan-
dard. IR spectra were recorded with a Bruker Tensor 27 FT-IR spec-
trophotometer using KBr pellets. GC-MS was performed on a
Finnigan Trace DSQ chromatograph. The morphology of CuO
nanoparticles was tested by TEM, Tecnai-12 Philip Apparatus Co.,
United States. The nano-CuO was purchased from Sigma-Aldrich
and the size of CuO was less than 50 nm. Petroleum ether used re-
fers to the fraction boiling in the range of 60–90 °C.
particles (0.1 equiv), K2CO3 (2 equiv), and DMSO (2 mL) in a
Schlenk tube was stirred under an argon atmosphere at 160 °C. The
progress of the reaction was monitored by TLC (EtOAc–PE 1:100
or pure PE). After completion of the reaction, the reaction mixture
was treated with H2O (5 mL) and EtOAc (8 mL). The organic and
aqueous layers were then separated, and the aqueous layer was ex-
tracted with EtOAc (5 × 3 mL). The combined organic extracts were
dried (Na2SO4), then filtered, and evaporated under vacuum. The
residue was purified by flash column chromatography (petroleum
ether or petroleum ether–EtOAc) to afford the corresponding cou-
pling products.
Sonogashira Coupling Reaction with the Aid of CuO Nanopar-
ticles; General Procedure
A mixture of aryl halide (1.5 mmol), alkyne (1.0 mmol), CuO nano-
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1, 2-Diphenylethyne
2-m-Tolyl-1-p-tolylethyne
IR (KBr): 2927, 1493, 753, 685 cm–1.
IR (KBr): 3031, 2915, 1589, 1509, 816, 783 cm–1.
1H NMR (600 MHz, CDCl3): d = 7.31–7.35 (m, 6 H), 7.46 (d,
J = 7.6 Hz, 4 H).
13C NMR (150 MHz, CDCl3): d = 89.3, 123.2, 128.2, 128.3, 131.6.
MS (ES): m/z = 178 [M]+.
1H NMR (600 MHz, CDCl3): d = 2.35 (d, J = 9.3 Hz, 6 H), 7.14 (t,
J = 8.7 Hz, 3 H), 7.23 (t, J = 9.0 Hz, 1 H), 7.32 (d, J = 7.4 Hz, 1 H),
7.35 (s, 1 H), 7.41 (d, J = 7.3 Hz, 2 H).
13C NMR (150 MHz, CDCl3): d = 21.2, 21.5, 88.8, 89.2, 120.2,
123.2, 128.2, 128.6, 128.9, 129.0, 131.4, 132.1, 137.9, 138.2.
1-Methyl-4-(2-phenylethynyl)benzene
MS (ES): m/z = 206 [M]+.
IR (KBr): 3040, 2918, 2211, 1591, 1508, 817, 754 cm–1.
2-m-Tolyl-1-o-tolylethyne
1H NMR (600 MHz, CDCl3): d = 2.36 (s, 3 H), 7.14 (d, J = 7.5 Hz,
2 H), 7.32 (t, J = 5.9 Hz, 3 H), 7.42 (d, J = 7.5 Hz, 2 H), 7.51 (d,
J = 7.0 Hz, 2 H).
13C NMR (150 MHz, CDCl3): d = 20.4, 87.7, 88.5, 119.2, 122.5,
127.0, 127.2, 128.0, 130.5, 130.5, 137.3.
IR (KBr): 3025, 1591, 1486, 785, 754 cm–1.
1H NMR (600 MHz, CDCl3): d = 2.35 (s, 3 H), 2.51 (s, 3 H), 7.13–
7.17 (m, 2 H), 7.23 (d, J = 8.8 Hz, 3 H), 7.35 (t, J = 8.3 Hz, 2 H),
7.49 (d, J = 7.4 Hz, 1 H).
13C NMR (150 MHz, CDCl3): d = 19.7, 20.2, 86.9, 92.4, 122.0,
122.3, 124.5, 127.1, 127.2, 127.5, 128.0, 128.4, 130.7, 131.0, 136.9,
139.1.
MS (ES): m/z = 191 [M]+.
1-Methyl-2-(2-phenylethynyl)benzene
IR (KBr): 3061, 3026, 2919, 2214, 1599, 1493, 754, 698 cm–1.
MS (ES): m/z = 206 [M]+.
1H NMR (600 MHz, CDCl3): d = 2.51 (s, 3 H), 7.15 (s, 1 H), 7.22
(t, J = 6.4 Hz, 2 H), 7.31–7.35 (m, 3 H), 7.49 (d, J = 7.5 Hz, 1 H),
7.53 (d, J = 7.1 Hz, 2 H).
13C NMR (150 MHz, CDCl3): d = 20.7, 88.3, 93.3, 123.1, 123.6,
125.5, 128.1, 128.3, 128.3, 129.4, 131.5, 131.8, 140.2.
1-[2-(4-Methoxyphenyl)ethynyl]-3-methylbenzene
IR (KBr): 2961, 1597, 1508, 1173, 884, 791 cm–1.
1H NMR (600 MHz, CDCl3): d = 2.34 (s, 3 H), 3.82 (s, 3 H), 6.87
(d, J = 8.0 Hz, 2 H), 7.12 (d, J = 7.4 Hz, 1 H), 7.22 (t, J = 7.6 Hz, 1
H), 7.32 (d, J = 7.5 Hz, 1 H), 7.34 (s, 1 H), 7.46 (d, J = 8.1 Hz, 2 H).
13C NMR (150 MHz, CDCl3): d = 21.2, 55.2, 88.2, 89.0, 113.9,
115.4, 123.3, 128.2, 128.5, 128.8, 132.0, 133.0, 137.9, 159.5.
MS (ES): m/z = 192 [M]+.
1-Methoxy-4-(2-phenylethynyl)benzene
IR (KBr): 2910, 2212, 1597, 1507, 1104, 830 cm–1.
MS (ES): m/z = 222 [M]+.
1H NMR (600 MHz, CDCl3): d = 3.74 (s, 3 H), 6.80 (d, J = 8.2 Hz,
2 H), 7.23–7.26 (m, 3 H), 7.40 (d, J = 8.1 Hz, 2 H), 7.44 (d, J = 7.0
Hz, 2 H).
13C NMR (150 MHz, CDCl3): d = 55.2, 88.0, 89.3, 113.9, 115.3,
123.5, 127.9, 128.2, 131.3, 133.0, 159.5.
1-[2-(3-Methoxyphenyl)ethynyl]-3-methylbenzene
IR (KBr): 3004, 2950, 2837, 2208, 1595, 1485, 1241, 782, 687
cm–1.
1H NMR (600 MHz, CDCl3): d = 2.35 (s, 3 H), 3.82 (s, 3 H), 6.89
(d, J = 8.3 Hz, 1 H), 7.05 (s, 1 H), 7.11–7.15 (m, 2 H), 7.24 (d,
J = 8.0 Hz, 2 H), 7.34 (d, J = 7.5 Hz, 1 H), 7.36 (s, 1 H).
MS (ES): m/z = 208 [M]+.
13C NMR (150 MHz, CDCl3): d = 21.2, 55.2, 88.9, 89.3, 114.8,
116.2, 122.9, 124.1, 124.3, 128.2, 128.7, 129.2, 129.3, 132.2, 138.0,
159.3.
1-Methoxy-3-(2-phenylethynyl)benzene
IR (KBr): 2956, 1587, 1489, 1229, 1075, 794, 763 cm–1.
1H NMR (600 MHz, CDCl3): d = 3.82 (s, 3 H), 6.90 (d, J = 8.3 Hz,
1 H), 7.06 (s, 1 H), 7.13 (d, J = 7.5 Hz, 1 H), 7.25 (d, J = 5.4 Hz, 1
H), 7.34 (d, J = 5.8 Hz, 3 H), 7.53 (d, J = 6.4 Hz, 2 H).
13C NMR (150 MHz, CDCl3): d = 55.2, 89.1, 89.2, 114.9, 116.3,
123.1, 124.1, 124.2, 128.3, 128.3, 129.4, 131.6, 159.3.
MS (ES): m/z = 222 [M]+.
1-Methyl-3-[2-(4-nitrophenyl)ethynyl]benzene
IR (KBr): 2964, 2202, 1590, 1510, 1340, 850, 796 cm–1.
1H NMR (600 MHz, CDCl3): d = 2.37 (s, 3 H), 7.21 (d, J = 7.6 Hz,
1 H), 7.28 (t, J = 7.6 Hz, 1 H), 7.37 (t, J = 10.1 Hz, 2 H), 7.65 (d,
J = 8.2 Hz, 2 H), 8.21 (d, J = 8.1 Hz, 2 H).
13C NMR (150 MHz, CDCl3): d = 21.2, 87.2, 94.9, 121.8, 123.6,
128.4, 128.9, 130.1, 130.3, 132.2, 132.3, 138.2, 146.8.
MS (ES): m/z = 208 [M]+.
1-Nitro-4-(2-phenylethynyl)benzene
IR (KBr): 2963, 2210, 1589, 1510, 1343, 856, 759 cm–1.
1H NMR (600 MHz, CDCl3): d = 7.39 (s, 3 H), 7.56 (s, 2 H), 7.66
(d, J = 7.8 Hz, 2 H), 8.22 (d, J = 7.8 Hz, 2 H).
MS (ES): m/z = 237 [M]+.
13C NMR (150 MHz, CDCl3): d = 87.5, 94.6, 122.0, 123.6, 128.5,
1-Chloro-3-(2-phenylethynyl)benzene
IR (KBr): 3064, 2223, 1593, 1490, 783, 751 cm–1.
129.2, 130.2, 131.8, 132.2, 146.9.
MS (ES): m/z = 223 [M]+.
1H NMR (600 MHz, CDCl3): d = 7.24–7.31 (m, 2 H), 7.35 (s, 3 H),
7.40 (d, J = 7.3 Hz, 1 H), 7.52 (s, 3 H).
13C NMR (150 MHz, CDCl3): d = 87.9, 90.5, 122.7, 125.0, 128.4,
128.4, 128.6, 129.5, 129.7, 131.4, 131.6, 134.1.
1-Methyl-3-(2-phenylethynyl)benzene
IR (KBr): 3052, 2920, 2208, 1600, 1493, 784, 754 cm–1.
1H NMR (600 MHz, CDCl3): d = 2.35 (s, 3 H), 7.10 (d, J = 7.0 Hz,
1 H), 7.22 (t, J = 8.5 Hz, 2 H), 7.32 (s, 4 H), 7.52 (d, J = 6.0 Hz, 2
MS (ES): m/z = 212 [M]+.
H).
1-Chloro-3-(2-p-tolylethynyl)benzene
13C NMR (150 MHz, CDCl3): d = 21.2, 89.0, 89.6, 123.1, 123.4,
128.1, 128.2, 128.3, 128.7, 129.1.
MS (ES): m/z = 192 [M]+.
IR (KBr): 2921, 1588, 1465, 816, 788, 710 cm–1.
1H NMR (600 MHz, CDCl3): d = 2.36 (s, 3 H), 7.16 (d, J = 7.4 Hz,
2 H), 7.24–7.29 (m, 2 H), 7.38–7.42 (m, 3 H), 7.50 (s, 1 H).
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Nano-CuO Catalyst for Sonogashira Coupling Reaction
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13C NMR (150 MHz, CDCl3): d = 21.5, 87.3, 90.7, 119.6, 125.2,
128.2, 129.1, 129.5, 129.6, 131.3, 131.5, 134.1, 138.8.
Acknowledgment
This work was supported by the National Natural Science Founda-
tion of China (20702043) and by Program for New Century Excel-
lent Talents in Yangzhou University.
MS (ES): m/z = 226 [M]+.
1-[2-(3-Chlorophenyl)ethynyl]-2-methylbenzene
IR (KBr): 3063, 1555, 1450, 876, 750, 714 cm–1.
1H NMR (600 MHz, CDCl3): d = 2.50 (s, 3 H), 7.18 (t, J = 7.2 Hz,
1 H), 7.24 (d, J = 5.9 Hz, 2 H), 7.26–7.31 (m, 2 H), 7.40 (d, J = 7.2
Hz, 1 H), 7.49 (d, J = 7.5 Hz, 1 H), 7.51 (s, 1 H).
13C NMR (150 MHz, CDCl3): d = 20.7, 89.5, 91.8, 122.4, 125.2,
125.6, 128.3, 128.6, 129.5, 129.5, 129.6, 131.3, 131.9, 134.1, 140.3.
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IR (KBr): 2961, 2220, 1591, 1506, 1174, 885, 829, 790 cm–1.
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Hz, 2 H), 7.49 (s, 1 H).
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MS (ES): m/z = 242 [M]+.
1-Chloro-3-[2-(3-methoxyphenyl)ethynyl]benzene
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Kooyman, P. J.; Boerleider, R.; Jansen, E.; Elsevier, C. J.;
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351, 891. (f) Mao, J.-C.; Wu, M.-Y.; Xie, G.-L.; Ji, S.-J.
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2005, 70, 4393. (i) Fabrizi, G.; Goggiamani, A.; Sferrazza,
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IR (KBr): 2985, 2225, 1569, 1483, 1125, 926, 871, 784 cm–1.
1H NMR (600 MHz, CDCl3): d = 3.82 (s, 3 H), 6.90–6.91 (d, J = 8.2
Hz, 2 H), 7.05 (s, 1 H), 7.12 (d, J = 7.4 Hz, 1 H), 7.25–7.31 (m, 3
H), 7.41 (d, J = 7.2 Hz, 1 H), 7.52 (s, 1 H).
13C NMR (150 MHz, CDCl3): d = 55.3, 87.7, 90.4, 115.2, 116.3,
123.7, 124.2, 124.9, 128.5, 129.4, 129.5, 129.7, 131.4, 134.1, 159.3.
MS (ES): m/z = 241 [M]+.
1-Chloro-3-[2-(4-nitrophenyl)ethynyl]benzene
(j) Carpita, A.; Ribecai, A. Tetrahedron Lett. 2009, 50, 204.
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IR (KBr): 3067, 2217, 1647, 1593, 1513, 883, 794, 748 cm–1.
1H NMR (600 MHz, CDCl3): d = 7.33 (t, J = 7.7 Hz, 1 H), 7.37 (d,
J = 8.0 Hz, 1 H), 7.44, (d, J = 7.5 Hz, 1 H), 7.55 (s, 1 H), 7.67 (d,
J = 8.0 Hz, 2 H), 8.23 (d, J = 8.0 Hz, 2 H).
13C NMR (150 MHz, CDCl3): d = 88.4, 92.9, 123.6, 123.8, 129.5,
129.6, 129.7, 129.9, 131.6, 132.3, 134.4, 147.2.
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MS (ES): m/z = 257 [M]+.
2-(2-Phenylethynyl)naphthalene
IR (KBr): 3054, 1596, 1494, 748 cm–1.
1H NMR (600 MHz, CDCl3): d = 7.35 (d, J = 7.2 Hz, 3 H), 7.48 (d,
J = 2.7 Hz, 2 H), 7.57 (d, J = 7.2 Hz, 3 H), 7.80 (s, 3 H), 8.04 (s, 1
H).
13C NMR (150 MHz, CDCl3): d = 89.7, 89.8, 120.6, 123.4, 126.5,
126.6, 127.8, 128.0, 128.3, 128.3, 128.4, 131.4, 131.7, 132.8, 133.1.
MS (ES): m/z = 228 [M]+.
1-(Hex-1-ynyl)benzene
IR (KBr): 3059, 2931, 2867, 2232, 1489, 1450, 1378, 1238, 754,
691 cm–1.
1H NMR (600 MHz, CDCl3): d = 0.95 (t, J = 6.2 Hz, 3 H), 1.49 (t,
J = 5.7 Hz, 2 H), 1.59 (d, J = 6.3 Hz, 2 H), 2.41 (d, J = 6.0 Hz, 2 H),
7.25 (d, J = 6.0 Hz. 3 H), 7.38 (d, J = 5.5 Hz, 2 H).
13C NMR (150 MHz, CDCl3): d = 13.6, 19.1, 22.0, 30.9, 80.6, 90.4,
124.2, 127.4, 128.1, 131.5.
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K.; Hara, T.; Mizugaki, T.; Ebitani, K.; Kaneda, K. J. Am.
Chem. Soc. 2004, 126, 10657. (i) Su, F.-Z.; Liu, Y.-M.;
Wang, L.-C.; Cao, Y.; He, H.-Y.; Fan, K.-N. Angew. Chem.
MS (ES): m/z = 158 [M]+.
Synthesis 2011, No. 11, 1792–1798 © Thieme Stuttgart · New York

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