A highly efficient and recyclable Pd(PPh3)4/PEG-400 system for Stille cross-coupling reactions of organostannanes with aryl bromides

Article abstract of DOI:10.3184/174751917X15045169836226

Pd(PPh₃)₄ in PEG-400 is shown to be a highly efficient catalyst for the Stille cross-coupling reactions of various organotin compounds with aryl bromides. The reaction could be conducted at 80 °C using NaOAc as base, yielding a variety of biaryls, alkynes and alkenes in good to excellent yields. The isolation of the products was readily performed by extraction with petroleum ether and the Pd(PPh₃)₄/PEG-400 system could be easily recycled and reused five times without any significant loss of activity.

Full text of DOI:10.3184/174751917X15045169836226

JOURNAL OF CHEMICAL RESEARCH 2017
VOL. 41 SEPTEMBER, 547–550
RESEARCH PAPER 547
A highly efficient and recyclable Pd(PPh3)4/PEG-400 system for Stille cross-
coupling reactions of organostannanes with aryl bromides
Xue Huanga, Fang Yaob, Ting Weia and Mingzhong Caia*
aKey Laboratory of Functional Small Organic Molecule, Ministry of Education and Department of Chemistry, Jiangxi Normal University, Nanchang 330022, P.R. China
bCollege of Chemical and Material Engineering, Quzhou University, Quzhou 324000, P.R. China
Pd(PPh3)4 in PEG-400 is shown to be a highly efficient catalyst for the Stille cross-coupling reactions of various organotin compounds with
aryl bromides. The reaction could be conducted at 80 °C using NaOAc as base, yielding a variety of biaryls, alkynes and alkenes in good
to excellent yields. The isolation of the products was readily performed by extraction with petroleum ether and the Pd(PPh3)4/PEG-400
system could be easily recycled and reused five times without any significant loss of activity.
Keywords: palladium, Stille coupling, aryl bromide, PEG-400
The palladium-catalysed cross-coupling of organostannanes
with organic halides and triflates, known as the Stille reaction,
represents one of the most important transformations in
constructing carbon–carbon bonds in organic synthesis.1–5 The
Stille reaction has been widely applied in organic synthesis6–10
since a wide range of functionality can be tolerated on either
coupling partner. The yields of cross-coupled products are
often high and the organotin reagents can be readily prepared,
purified and stored. However, most of these reactions are
performed in organic solvents with a homogeneous palladium
complex such as Pd(PPh3)4, PdCl2(PPh3)2 and PdCl2(MeCN)2 as
catalyst or catalyst precursor, which makes the recovery of the
metal tedious if not impossible and might result in unacceptable
palladium contamination of the product. These problems are
of particular environmental and economic concern in industry,
especially the pharmaceutical industry. Therefore, from the
standpoint of green and sustainable chemistry, the avoidance
of any use of hazardous and expensive organic solvents and
the development of a recyclable and reusable catalyst system
that allows for highly efficient Stille cross-coupling is highly
desirable. The issue of potential contamination with toxic
organotin remains.
To satisfy both recyclability and environmental concerns, a
simple and efficient method is to immobilise the catalyst in a
liquid phase by dissolving it into a non-volatile and non-mixing
liquid, such as an ionic liquid11–15 or a polyethylene glycol
(PEG).16–23 Ionic liquids have some disadvantages, such as a
complicated method for their preparation. Their environmental
safety is still debated since toxicity and environmental burden
data are not available for most ionic liquids. By contrast,
PEGs are commercially readily available and inexpensive,
thermally stable, recoverable, biodegradable and non-toxic
compounds, which serve as efficient media for environmentally
friendly and safe chemical reactions.24–26 In recent years, PEGs
have been widely utilised as reaction media for a range of
palladium-catalysed carbon–carbon bond formation reactions
such as the Heck coupling,16,17 Suzuki-Miyaura coupling,18,19
the homocoupling and cross-coupling of aryl halides,20 the
direct arylation of 1,2,3-triazoles with aryl bromides21 and
carbonylative Suzuki22 or Sonogashira23 cross-couplings
with facile recyclability of solvents and palladium catalysts.
Recently, J.-X. Wang and co-workers reported a palladium-
catalysed atom-efficient Stille cross-coupling reaction of
tetraphenylstannane with aryl bromides in PEG-400, but no
recyclability of the catalytic system was described.27,28 To
the best of our knowledge, the cross-coupling reactions of
alkynylstannanes and vinylstannanes with aryl halides in PEGs
have not been reported thus far. We report here the application
of the Pd(PPh3)4/PEG-400 system as a highly efficient and
reusable catalytic medium for the Stille cross-coupling reactions
of various organotin compounds with aryl bromides leading to
a variety of biaryls, alkynes and alkenes in good to excellent
yields (Scheme 1).
Results and discussion
Initially, the Stille cross-coupling of 4-bromobenzonitrile
with PhSnBu3 in PEG-400 was chosen as a model reaction
to determine the optimum conditions and the results are
summarised in Table 1. Firstly, the effect of base on the model
reaction was examined by using Pd(PPh3)4 as the catalyst at
80 ºC (Table 1, entries 1–6). Of the bases tested, K3PO4, KF,
NaHCO3 and NaOAc afforded good yields of product with
NaOAc giving the best result, whilst K2CO3 and Na2CO3
were substantially less effective. We next turned our attention
to the effect of catalyst on the model reaction. When other
palladium catalysts such as PdCl2(PPh3)2, PdCl2(PhCN)2 and
Pd(OAc)2/2PPh3 were used, the desired 4-cyanonbiphenyl was
obtained in lower yields (Table 1, entries 7–9), so Pd(PPh3)4
was the best choice. For the temperatures evaluated (60, 80
and 100 °C), 80 °C was found to be the most efficient (Table
1, entries 6, 10 and 11). Finally, the amount of catalyst was also
screened. Reducing the quantity of the catalyst resulted in a
R2
Br
Pd(PPh3)4 (1 mol%)
NaOAc (1 equiv), PEG-400, 80 oC
R1
Bu3Sn-R2
R1
+
2
1
3
R2 = aryl, alkynyl, vinyl
Scheme 1
* Correspondent. E-mail: caimzhong@163.com

548 JOURNAL OF CHEMICAL RESEARCH 2017
Table 1 Optimisation of the Stille cross-coupling of 4-bromobenzonitrile
Table 2 Stille cross-coupling reactions of organostannanes with aryl
with PhSnBu3a
bromidesa
Br
R1
Catalyst/PEG-400
Pd(PPh3)4 (1 mol%)
+
R1
Bu3Sn R2
N
C
Br
PhSnBu3
N
C
Ph
R2
+
NaOAc (1.0 equiv), PEG-400, 80 o
C
Base, temp.
3
2
1
Entry Catalyst
Base
Temp. (ºC) Time (h) Yield (%)b
Entry R1
R2
Time (h) Product Yield (%)b
1
2
3
4
5
6
7
8
9
10
11
12c
13d
Pd(PPh )
Pd(PPh3)4
Pd(PPh3)4
Pd(PPh3)4
Pd(PPh3)4
Pd(PPh3)44
K2CO3
Na2CO3
K PO4
K3F
NaHCO
NaOAc 3
NaOAc
NaOAc
80
80
80
80
80
80
80
80
80
60
100
80
80
6
6
5
5
5
3
3
6
6
8
2
8
2
49
37
78
74
62
91
83
65
61
69
88
76
90
1
2
3
4
5
6
7
8
H
Ph
Ph
Ph
Ph
PhC≡C
PhC≡C
PhC≡C
PhC≡C
3
3
3
3
4
3
3
5
4
4
4
5
4
4
5
3
3
3
5
4
5
4
3
3
4
3
3a
3b
3c
3d
3e
3f
3g
3h
3i
91
93
91
92
89
93
92
82
85
87
88
82
88
85
81
89
83
86
81
87
85
90
86
89
83
87
4-Me
4-NC
4-MeCO
H
4-O2N
4-MeOCO
4-MeO
4-Me
4-Cl
PdCl (P3Ph )
PdCl22(PhC3N2)2
Pd(OAc)2/2PPh3 NaOAc
Pd(PPh )
Pd(PPh3)4
Pd(PPh3)4
Pd(PPh33)44
9
PhC≡C
NaOAc
NaOAc
NaOAc
NaOAc
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
n-C H C≡C
n-C4H9C≡C
n-C44H99C≡C
MeOCH2C≡C
Me SiC≡C
Me3SiC≡C
CH3=CH
3j
3k
3l
3-NC
3-Me
H
aReaction conditions: 4-bromobenzonitrile (0.5 mmol), PhSnBu3 (0.6 mmol), catalyst
(1 mol%), base (0.5 mmol) in PEG-400 (2 mL) under Ar.
bIsolated yield.
c0.5 mol% catalyst was used.
d2 mol% catalyst was used.
3m
3n
3o
3p
3q
3r
3s
3t
3u
3v
3w
3x
3y
3z
4-Cl
4-MeO
4-NC
4-O2N
4-MeCO
4-MeO
4-Cl
4-MeO
4-Me
3-NC
4-O2N
4-Me
4-O2N
CH2=CH
CH2=CH
(E)2-BuCH=CH
(E)-BuCH=CH
(E)-PhCH=CH
(E)-PhCH=CH
(Z)-BuCH=CH
(Z)-BuCH=CH
(Z)-PhCH=CH
(Z)-PhCH=CH
decreased yield and a longer reaction time (Table 1, entry 12).
Increasing the amount of the catalyst could shorten the reaction
time, but did not improve the yield (Table 1, entry 13). Taken
together, excellent results were obtained when the coupling
reaction was carried out under Ar for 3 h with 1 mol% of
Pd(PPh3)4 as the catalyst and NaOAc (1.0 equiv.) as the base in
PEG-400 at 80 °C (Table 1, entry 6).
aReaction conditions: aryl bromide (0.5 mmol), organotin reagent (0.6 mmol), Pd(PPh3)4
(1 mol%), NaOAc (0.5 mmol) in PEG-400 (2 mL) at 80 ºC under Ar.
bIsolated yield.
With the optimised conditions established, we investigated
the scope of this palladium(0)-catalysed Stille cross-coupling
reaction. The results are listed in Table 2. Firstly, the Stille
cross-coupling reactions of aryl bromides with tributyl(phenyl)
stannane were investigated under the optimised conditions.
As shown in Table 2, both electron-deficient and electron-
rich aryl bromides were good substrates and gave the desired
biphenyls 3a–d in excellent yields (Table 2, entries 1–4). The
developed methodology was also applicable for the Stille cross-
coupling reactions of alkynylstannanes and alkenylstannanes
with aryl bromides. The Stille coupling reactions of
tributyl(phenylethynyl)stannane with aryl bromides also
proceeded smoothly at 80 ºC in PEG-400 with NaOAc as base to
give the corresponding diaryl alkynes 3e–i in good to excellent
yields (Table 2, entries 5–9). The reactivity of aryl bromides
with an electron-withdrawing group was higher than that of aryl
bromides with an electron-donating group. In addition, aliphatic
alkynylstannanes such as tributyl(hex-1-ynyl)stannane,
tributyl(3-methoxyprop-1-ynyl)stannane and 1-tributylstannyl-
2-trimethylsilylethyne were also good coupling partners
and coupled effectively with a variety of aryl bromides to
afford the desired alkyl- and aryl-substituted alkynes 3j–m
and trimethylsilyl- and aryl-substituted alkynes 3n and 3o in
high yields (Table 2, entries 10–15), the trimethylsilyl group
remaining intact. The reactions of tributyl(vinyl)stannane
with aryl bromides gave the substituted styrenes 3p–r in good
yields (Table 2, entries 16–18). To our delight, the Stille cross-
coupling reactions of a variety of aryl bromides with (E)- or
(Z)-alkenylstannanes also proceeded smoothly at 80 ºC in
PEG-400 to afford the corresponding cross-coupled products
in high yields with retention of configuration (Table 2, entries
19–26). The reactivity of the electron-deficient aryl bromides
was higher than that of the electron-rich aryl bromides. The
optimised catalyst system was quite general and compatible
with a wide range of functional groups such as nitro, cyano,
chloro, methoxy, carbonyl and silyl on either coupling partner.
To examine the reusability of Pd(PPh3)4 and PEG-400, the
cross-coupling reaction of methyl 4-bromobenzoate (0.5 mmol)
with tributyl(phenylethynyl)stannane (0.6 mmol) was evaluated
in the presence of Pd(PPh3)4 (1.0 mol%) and NaOAc (0.5 mmol)
in PEG-400 (2.0 mL) at 80 ºC for 3 h. As demonstrated in
Fig. 1, we were pleased to observe that the Pd(PPh3)4/PEG-
400 system could be recycled and reused five times without
observing any significant loss of catalytic activity. After the
first experiment, the reaction mixture was extracted three times
with light petroleum ether (30–60 °C) and the Pd(PPh3)4/PEG-
400 system was then subjected to a second run of the reaction
by charging with the same substrates [methyl 4-bromobenzoate,
tributyl(phenylethynyl)stannane and NaOAc] without the
addition of Pd(PPh3)4. The results of six runs showed that they
were almost consistent in yields within an average reaction
time of 4 h (92, 91, 90, 91, 89 and 89% respectively). We also
determined the amount of palladium in the product 3g isolated
after the first cycle by inductively coupled plasma atom emission
spectrometry (ICP-AES) analysis. It was found that only 0.3
ppm of palladium was detected in the isolated product 3g.
In conclusion, a highly efficient Pd(PPh3)4/PEG-400 system
for the Stille cross-coupling reaction of various organotin
compounds with aryl bromides has been developed. In the
presence of Pd(PPh3)4 (1 mol%), the reactions of a variety of
aryl bromides with various organotin compounds proceeded
smoothly and efficiently at 80 °C using NaOAc (1.0 equiv.) as
base in PEG-400 to furnish the corresponding cross-coupled
products in good to excellent yields. The Pd(PPh3)4/PEG-

JOURNAL OF CHEMICAL RESEARCH 2017 549
MHz, CDCl3): δ 141.2, 138.4, 137.0, 129.5, 128.7, 127.3, 127.2, 127.0,
21.1.
100
80
60
40
20
0
4-Cyanobiphenyl (3c): White solid; m.p. 85–86 ºC (lit.32 86–87 ºC);
IR (KBr): 2226, 1605, 1483, 848, 770, 697 cm–1; 1H NMR (400 MHz,
CDCl3): δ 7.72 (d, J = 8.0 Hz, 2H), 7.67 (d, J = 8.0 Hz, 2H), 7.58
(d, J = 7.6 Hz, 2H), 7.48 (t, J = 7.6 Hz, 2H), 7.43 (t, J = 7.6 Hz, 1H);
13C NMR (100 MHz, CDCl3): δ 145.7, 139.2, 132.6, 129.1, 128.7, 127.8,
127.2, 119.0, 110.9.
4-Acetylbiphenyl (3d): White solid; m.p. 119–121 ºC (lit.32
120–122 ºC); IR (KBr): 2999, 1681, 1602, 1264, 961, 766 cm–1;
1H NMR (400 MHz, CDCl3): δ 8.02 (d, J = 7.6 Hz, 2H), 7.68 (d, J = 7.6
Hz, 2H), 7.62 (d, J = 7.6 Hz, 2H), 7.46 (t, J = 7.4 Hz, 2H), 7.42–7.38 (m,
1H), 2.63 (s, 3H); 13C NMR (100 MHz, CDCl3): δ 197.7, 145.7, 139.9,
135.9, 129.0, 128.9, 128.2, 127.3, 127.2, 26.6.
1,2-Diphenylacetylene (3e): White solid; m.p. 60–61 °C (lit.33
59–60 ºC); IR (KBr): 3063, 1599, 1492, 756, 689 cm–1; 1H NMR (400
MHz, CDCl3): δ 7.55–7.52 (m, 4H), 7.37–7.32 (m, 6H); 13C NMR (100
MHz, CDCl3): δ 131.6, 128.4, 128.3, 123.3, 89.4.
1-(4-Nitrophenyl)-2-phenylacetylene (3f): Yellow solid; m.p.
120–121 °C (lit.33 121–122 ºC); IR (KBr): 3082, 2217, 1592, 1511, 1495,
858, 765, 690 cm–1; 1H NMR (400 MHz, CDCl3): δ 8.23 (d, J = 8.8 Hz,
2H), 7.67 (d, J = 8.8 Hz, 2H), 7.58–7.55 (m, 2H), 7.41–7.37 (m, 3H);
13C NMR (100 MHz, CDCl3): δ 146.9, 132.3, 131.8, 130.3, 129.3, 128.5,
123.7, 122.1, 94.7, 87.5.
Methyl 4-phenylethynylbenzoate (3g): White solid; m.p. 120 °C (lit.33
119–120 ºC); IR (KBr): 2948, 2218, 1717, 1605, 1438, 1109, 770 cm–1;
1H NMR (400 MHz, CDCl3): δ 8.04–8.02 (m, 2H), 7.61–7.58 (m, 2H),
7.56–7.54 (m, 2H), 7.38–7.36 (m, 3H), 3.93 (s, 3H); 13C NMR (100
MHz, CDCl3): δ 166.6, 131.8, 131.5, 129.5, 129.4, 128.8, 128.5, 128.0,
122.7, 92.4, 88.6, 52.3.
1-(4-Methoxyphenyl)-2-phenylacetylene (3h): White solid; m.p.
58–59 °C (lit.33 59–60 ºC); IR (KBr): 3024, 2212, 1602, 1498, 1185,
835, 750, 690 cm–1; 1H NMR (400 MHz, CDCl3): δ 7.52–7.43 (m, 4H),
7.32–7.29 (m, 3H), 6.86–6.83 (m, 2H), 3.76 (s, 3H); 13C NMR (100
MHz, CDCl3): δ 159.5, 133.0, 131.4, 128.3, 127.9, 123.4, 115.5, 113.9,
89.4, 88.1, 55.2.
1-(4-Methylphenyl)-2-phenylacetylene (3i): White solid; m.p.
73–74 °C (lit.33 75–76 ºC); IR (KBr): 3029, 2968, 2859, 2215, 1594,
1509, 818, 690 cm–1; 1H NMR (400 MHz, CDCl3): δ 7.53–7.51 (m, 2H),
7.42 (d, J = 8.0 Hz, 2H), 7.36–7.27 (m, 3H), 7.14 (d, J = 8.0 Hz, 2H),
2.36 (s, 3H); 13C NMR (100 MHz, CDCl3): δ 138.4, 131.6, 131.5, 129.1,
128.3, 128.1, 123.5, 120.2, 89.6, 88.7, 21.5.
1
2
3
4
5
6
Reaction cycles
Fig. 1 Recycling of the catalytic system.
400 system could be recycled and reused five times without
observing any significant loss of catalytic activity. This protocol
will serve as an efficient and practical method for the synthesis
of a variety of biaryls, alkynes and alkenes although the use
of toxic organotin reagents, in excess, has to be acknowledged.
Currently, further efforts to extend the application of this system
to other palladium-catalysed transformations are underway in
our laboratory.
Experimental
All reagents were used as received without further purification. Both
tributyl(phenyl) stannane and tributyl(vinyl)stannane were purchased
from Sigma-Aldrich Co. Alkynylstannanes,29 (Z)-vinylstannanes30 and
(E)-vinylstannanes31 were prepared according to literature methods.
All reactions were carried out under an atmosphere of Ar in oven-dried
glassware with magnetic stirring. FTIR spectra were obtained on a
Nicolet MAGNA-IR 750 spectrometer.1H NMR spectra were recorded on
a Bruker Avance 400 spectrometer at 400 Mhz with TMS as an internal
standard using CDCl3 as the solvent. 13C NMR spectra were recorded
on the Bruker Avance 400 spectrometer at 100 Mhz using CDCl3 as the
solvent. Palladium content in the product was determined with ICP-AES.
Microanalyses were obtained using a PerkinElmer 240 elemental analyser.
1-(4-Chlorophenyl)hex-1-yne (3j): Colourless liquid; IR (neat): 2959,
1
2932, 2232, 1489, 1466, 827, 753 cm–1; H NMR (400 MHz, CDCl3):
Stille cross-coupling reaction of organotin reagents with aryl
bromides in PEG-400; general procedure
δ 7.31 (d, J = 8.4 Hz, 2H), 7.24 (d, J = 8.4 Hz, 2H), 2.40 (t, J = 7.2 Hz,
2H), 1.60–1.55 (m, 2H), 1.50–1.44 (m, 2H), 0.95 (t, J = 7.2 Hz, 3H);
13C NMR (100 MHz, CDCl3): δ 133.4, 132.8, 128.5, 122.6, 91.5, 79.5,
30.7, 22.0, 19.1, 13.7. Anal. calcd for C12H13Cl: C, 74.78; H, 6.80; found:
C, 74.52; H, 6.91%.
1-(3-Cyanophenyl)hex-1-yne (3k): Colourless liquid; IR (neat):
3069, 2958, 2873, 2232, 2227, 1597, 1478, 896, 798, 683 cm–1; 1H NMR
(400 MHz, CDCl3): δ 7.66 (s, 1H), 7.60–7.53 (m, 2H), 7.39 (t, J = 7.6
Hz, 1H), 2.42 (t, J = 7.2 Hz, 2H), 1.61–1.56 (m, 2H), 1.50–1.45 (m, 2H),
0.96 (t, J = 7.2 Hz, 3H); 13C NMR (100 MHz, CDCl3): δ 135.7, 135.0,
130.7, 129.1, 125.7, 118.3, 112.6, 93.4, 78.5, 30.5, 22.0, 19.1, 13.7. Anal.
calcd for C13H13N: C, 85.21; H, 7.15; N, 7.64; found: C, 85.02; H, 6.91;
N, 7.41%.
1-(3-Methylphenyl)hex-1-yne (3l): Colourless oil; IR (neat): 3037,
2959, 2932, 2228, 1603, 1580, 783 cm–1; 1H NMR (400 MHz, CDCl3):
δ 7.22–7.13 (m, 3H), 7.06 (d, J = 7.2 Hz, 1H), 2.40 (t, J = 7.2 Hz, 2H),
2.30 (s, 3H), 1.60–1.54 (m, 2H), 1.51–1.39 (m, 2H), 0.94 (t, J = 7.2 Hz,
3H); 13C NMR (100 MHz, CDCl3): δ 137.8, 132.2, 128.6, 128.4, 128.1,
123.9, 90.0, 80.7, 30.9, 22.1, 21.2, 19.1, 13.7. Anal. calcd for C13H16: C,
90.64; H, 9.36; found: C, 90.48; H, 9.23%.
A mixture of aryl bromide 1 (0.5 mmol), organotin reagent 2
(0.6 mmol), NaOAc (0.5 mmol) and Pd(PPh3)4 (0.005 mmol) in
PEG-400 (2 mL) was stirred at 80 °C under an argon atmosphere for
3–5 h until complete consumption of the aryl bromide was observed
as judged by TLC. After being cooled to room temperature, the
mixture was extracted three times with light petroleum ether (30–60
°C) (3 × 10 mL). The combined organic phases were concentrated
under reduced pressure and the residue was purified by flash column
chromatography on silica gel [light petroleum ether (30–60 °C)/ethyl
acetate] to afford the desired product 3.
The mixture of Pd(PPh3)4 and PEG-400 was then subjected to a
second run of the reaction by charging with the same substrates (aryl
bromide 1, organotin reagent 2 and NaOAc) under the same conditions
without further addition of Pd(PPh3)4.
Biphenyl (3a): White solid; m.p. 68–70 ºC (lit.32 69–70 ºC); IR
(KBr): 3033, 1569, 1478, 730, 690 cm–1; 1H NMR (400 MHz, CDCl3):
δ 7.63–7.53 (m, 4H), 7.43 (t, J = 7.6 Hz, 4H), 7.34 (t, J = 7.6 Hz, 2H);
13C NMR (100 MHz, CDCl3): δ 143.1, 128.9, 127.3, 127.2.
4-Methylbiphenyl (3b): White solid; m.p. 45–46 ºC (lit.32 46–47 ºC);
IR (KBr): 3053, 1486, 823, 757, 689 cm–1; 1H NMR (400 MHz, CDCl3):
δ 7.56 (d, J = 7.6 Hz, 2H), 7.48 (d, J = 7.6 Hz, 2H), 7.43–7.38 (m, 2H),
7.33–7.28 (m, 1H), 7.23 (d, J = 7.6 Hz, 2H), 2.38 (s, 3H); 13C NMR (100
1-Phenyl-3-methoxyprop-1-yne (3m): Colourless liquid; IR (neat):
1
2930, 2237, 1599, 1490, 1099, 757, 691 cm–1; H NMR (400 MHz,
CDCl3): δ 7.46–7.44 (m, 2H), 7.32–7.30 (m, 3H), 4.32 (s, 2H), 3.46 (s,
3H); 13C NMR (100 MHz, CDCl3): δ 131.8, 128.4, 128.3, 122.7, 86.4, 84.9,

550 JOURNAL OF CHEMICAL RESEARCH 2017
60.4, 57.7. Anal. calcd for C10H10O: C, 82.16; H, 6.84; found: C, 81.93; H,
6.61%.
δ 146.2, 144.6, 137.2, 129.3, 127.0, 123.5, 31.8, 28.5, 22.4, 13.9. Anal.
calcd for C12H15NO2: C, 70.22; H, 7.37; N, 6.82; found: C, 70.42; H, 7.51;
N, 6.59%.
1-(4-Chlorophenyl)-2-trimethylsilylacetylene (3n):34 Colourless liquid;
1
IR (neat): 3030, 2159, 1590, 1488, 1250, 844, 759, 685 cm–1; H NMR
(Z)-1-(4-Methylphenyl)-2-phenylethene (3y): Colourless oil; IR (neat):
1
3012, 1629, 1599, 1492, 821, 772 cm–1; H NMR (400 MHz, CDCl3): δ
(400 MHz, CDCl3): δ 7.38 (d, J = 8.4 Hz, 2H), 7.26 (d, J = 8.4 Hz, 2H),
0.24 (s, 9H); 13C NMR (100 MHz, CDCl3): δ 134.6, 133.2, 128.6, 121.7,
103.9, 95.4, –0.1.
7.28–7.19 (m, 5H), 7.15 (d, J = 8.0 Hz, 2H), 7.03 (d, J = 8.0 Hz, 2H), 6.56
(s, 2H), 2.32 (s, 3H); 13C NMR (100 MHz, CDCl3): δ 137.4, 136.9, 134.3,
130.2, 129.6, 128.9, 128.8, 128.7, 128.2, 127.0, 21.3. Anal. calcd for C15H14:
C, 92.74; H, 7.26; found: C, 92.50; H, 7.31%.
(Z)-1-(4-Nitrophenyl)-2-phenylethene (3z): Yellow solid; m.p.
60–61 °C; IR (KBr): 1627, 1592, 1505, 1342, 856, 778, 696 cm–1; 1H NMR
(400 MHz, CDCl3): δ 8.07 (d, J = 8.8 Hz, 2H), 7.37 (d, J = 8.8 Hz, 2H),
7.26–7.19 (m, 5H), 6.82 (d, J = 12.4 Hz, 1H), 6.62 (d, J = 12.4 Hz, 1H);
13C NMR (100 MHz, CDCl3): δ 146.6, 144.2, 136.1, 134.0, 129.7, 128.8,
128.6, 128.0, 127.9, 123.6. Anal. calcd for C14H11NO2: C, 74.65; H, 4.92; N,
6.22; found: C, 74.38; H, 4.71; N, 6.04%.
1-(4-Methoxyphenyl)-2-trimethylsilylacetylene
(3o):34 Colourless
liquid; IR (neat): 2156, 1606, 1508, 1249, 834, 756, 699 cm–1; 1H NMR
(400 MHz, CDCl3): δ 7.41 (d, J = 8.8 Hz, 2H), 6.81 (d, J = 8.8 Hz, 2H),
3.81 (s, 3H), 0.24 (s, 9H); 13C NMR (100 MHz, CDCl3): δ 159.7, 133.5,
115.3, 113.8, 105.2, 92.5, 55.3, 0.1.
4-Vinylbenzonitrile (3p):35 Colourless liquid; IR (neat): 3068, 2227,
1629, 1606, 1508, 1405, 846 cm–1; 1H NMR (400 MHz, CDCl3): δ 7.61 (d,
J = 8.4 Hz, 2H), 7.49 (d, J = 8.4 Hz, 2H), 6.73 (dd, J = 17.6, 10.9 Hz, 1H),
5.88 (d, J = 17.6 Hz, 1H), 5.45 (d, J = 10.9 Hz, 1H); 13C NMR (100 MHz,
CDCl3): δ 141.9, 135.3, 132.4, 126.7, 118.9, 117.7, 111.1.
1-Nitro-4-vinylbenzene (3q):35 Colourless liquid; IR (neat): 3014, 1633,
Acknowledgement
1
1531, 1485, 1348, 1314, 921, 852 cm–1; H NMR (400 MHz, CDCl3): δ
We thank the National Natural Science Foundation of China
(21462021) for financial support.
8.19 (d, J = 8.8 Hz, 2H), 7.54 (d, J = 8.8 Hz, 2H), 6.78 (dd, J = 17.6, 10.9
Hz, 1H), 5.94 (d, J = 17.6 Hz, 1H), 5.51 (d, J = 10.9 Hz, 1H); 13C NMR
(100 MHz, CDCl3): δ 147.1, 143.8, 134.9, 126.8, 123.9, 118.6.
1-Acetyl-4-vinylbenzene (3r): White solid; m.p. 33–34 °C (lit.35
35–36 ºC); IR (KBr): 3054, 2987, 1681, 1605, 1265, 739, 705 cm–1;
1H NMR (400 MHz, CDCl3): δ 7.92 (d, J = 8.4 Hz, 2H), 7.48 (d,
J = 8.4 Hz, 2H), 6.75 (dd, J = 17.6, 10.9 Hz, 1H), 5.87 (d, J = 17.6 Hz, 1H),
5.40 (d, J = 10.9 Hz, 1H), 2.59 (s, 3H); 13C NMR (100 MHz, CDCl3): δ
197.5, 142.1, 136.3, 135.9, 128.7, 126.3, 116.7, 26.6.
Received 14 June 2017; accepted 30 August 2017
Paper 1704829
https://doi.org/10.3184/174751917X15045169836226
Published online: 8 September 2017
References
(E)-1-(4-Methoxyphenyl)hex-1-ene (3s): Colourless oil; IR (neat):
2957, 1608, 1577, 1464, 1174, 1038, 965, 804 cm–1; 1H NMR (400 MHz,
CDCl3): δ 7.27 (d, J = 8.4 Hz, 2H), 6.83 (d, J = 8.4 Hz, 2H), 6.32 (d,
J = 16.0 Hz, 1H), 6.09 (dt, J = 16.0, 7.2 Hz, 1H), 3.80 (s, 3H), 2.22–2.16
(m, 2H), 1.47–1.34 (m, 4H), 0.93 (t, J = 7.2 Hz, 3H); 13C NMR (100 MHz,
CDCl3): δ 158.6, 130.9, 129.1, 129.0, 127.0, 113.9, 55.3, 32.7, 31.7, 22.3,
14.0. Anal. calcd for C13H18O: C, 82.06; H, 9.54; found: C, 82.25; H,
9.71%.
(E)-1-(4-Chlorophenyl)hex-1-ene (3t): Colourless oil; IR (neat): 2957,
1593, 1490, 1469, 966, 809 cm–1; 1H NMR (400 MHz, CDCl3): δ 7.59 (d,
J = 8.4 Hz, 2H), 7.07 (d, J = 8.4 Hz, 2H), 6.30 (d, J = 16.0 Hz, 1H), 6.20
(dt, J = 16.0, 7.2 Hz, 1H), 2.21–2.18 (m, 2H), 1.47–1.32 (m, 4H), 0.92 (t, J
= 7.2 Hz, 3H); 13C NMR (100 MHz, CDCl3): δ 138.7, 134.2, 132.0, 130.5,
128.6, 127.1, 32.7, 31.5, 22.3, 14.0. Anal. calcd for C12H15Cl: C, 74.01; H,
7.76; found: C, 73.79; H, 7.57%.
(E)-1-(4-Methoxyphenyl)-2-phenylethene (3u): White solid; m.p.
134–135 °C (lit.36 135–136 ºC); IR (KBr): 2963, 1602, 1513, 1112, 967,
813 cm–1; 1H NMR (400 MHz, CDCl3): δ 7.49 (d, J = 7.6 Hz, 2H), 7.45
(d, J = 8.4 Hz, 2H), 7.34 (t, J = 7.6 Hz, 2H), 7.25–7.23 (m, 1H), 7.07 (d,
J = 16.4 Hz, 1H), 6.97 (d, J = 16.4 Hz, 1H), 6.90 (d, J = 8.4 Hz, 2H), 3.83
(s, 3H); 13C NMR (100 MHz, CDCl3): δ 159.3, 137.7, 130.2, 128.6, 128.2,
127.7, 127.2, 126.7, 126.3, 114.2, 55.3.
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(E)-1-(4-Methylphenyl)-2-phenylethene (3v): White solid; m.p.
117–118 °C (lit.36 118–119 ºC); IR (KBr): 3023, 1643, 1594, 1511, 970, 809,
690 cm–1; 1H NMR (400 MHz, CDCl3): δ 7.50 (d, J = 7.6 Hz, 2H), 7.41 (d,
J = 8.0 Hz, 2H), 7.35 (t, J = 7.6 Hz, 2H), 7.26–7.22 (m, 1H), 7.16 (d, J = 8.0
Hz, 2H), 7.07 (s, 2H), 2.36 (s, 3H); 13C NMR (100 MHz, CDCl3): δ 137.6,
137.5, 134.6, 129.4, 128.7, 128.6, 127.7, 127.4, 126.5, 126.4, 21.3.
(Z)-1-(3-Cyanophenyl)hex-1-ene (3w): Colourless oil; IR (neat): 3065,
2958, 2927, 2230, 1643, 1597, 1575, 1465, 806, 687 cm–1; 1H NMR (400
MHz, CDCl3): δ 7.54 (s, 1H), 7.51–7.40 (m, 3H), 6.36 (d, J = 11.6 Hz, 1H),
5.78 (dt, J = 11.6, 7.2 Hz, 1H), 2.31–2.25 (m, 2H), 1.48–1.32 (m, 4H), 0.90
(t, J = 7.2 Hz, 3H); 13C NMR (100 MHz, CDCl3): δ 138.9, 135.8, 133.1,
132.1, 129.9, 129.0, 126.6, 119.0, 112.3, 31.9, 28.3, 22.4, 13.9. Anal. calcd
for C13H15N: C, 84.28; H, 8.16; N, 7.56; found: C, 84.05; H, 7.97; N, 7.38%.
(Z)-1-(4-Nitrophenyl)hex-1-ene (3x): Yellow oil; IR (neat): 2958, 2929,
1
1640, 1596, 1516, 1343, 856 cm–1; H NMR (400 MHz, CDCl3): δ 8.18
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(d, J = 8.8 Hz, 2H), 7.41 (d, J = 8.8 Hz, 2H), 6.44 (d, J = 11.6 Hz, 1H),
5.87 (dt, J = 11.6, 7.2 Hz, 1H), 2.34–2.30 (m, 2H), 1.48–1.44 (m, 2H),
1.38–1.32 (m, 2H), 0.90 (t, J = 7.2 Hz, 3H); 13C NMR (100 MHz, CDCl3):