Effective palladium-catalyzed synthesis of triarylethene-based molecules in aqueous solution

Article abstract of DOI:10.1002/ejoc.201200577

Highly effective and selective Pd-catalyzed coupling reactions of 1,1-dibromo-1-alkenes with various arylboronic acids have been performed in aqueous solution under mild conditions. The method is simple, economic, and practical for the synthesis of triarylethene-based compounds. Copyright

Full text of DOI:10.1002/ejoc.201200577

Job/Unit: O20577
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FULL PAPER
DOI: 10.1002/ejoc.201200577
Effective Palladium-Catalyzed Synthesis of Triarylethene-Based Molecules in
Aqueous Solution
Yan Zhu,[a] Peng Sun,[a] Hailong Yang,[a] Linhua Lu,[a] Hong Yan,[a] Marc Creus,[b] and
Jincheng Mao*[a]
Keywords: Cross-coupling / Bromine / Alkenes / Boronic acids / Palladium
Highly effective and selective Pd-catalyzed coupling reac-
tions of 1,1-dibromo-1-alkenes with various arylboronic acids
have been performed in aqueous solution under mild condi-
tions. The method is simple, economic, and practical for the
synthesis of triarylethene-based compounds.
Introduction
luminescent (diphenylvinyl)benzene (DPVB)-based conju-
gated molecules could be used as emitting dyes in doped
OLEDs.[4]
Many compounds with important biological functions
contain triarylethene subunits, the extended π-conjugated
systems of which provide interesting properties. Examples
of such useful compounds include 1) the diphenyl-
(naphthyl)amine derivative I,[1] which is a charge-trans-
porting substance used in a electrophotographic photo-
receptor, 2) the basic esters of triphenylethylenes II,[2] which
are useful in the reduction of inflammation and edema and
as gonadotrophic inhibitors, and 3) chlorotriarylethylene
derivatives III,[3] which are employed as antineoplastic,
antiatherosclerotic, and hypocholesterolemic agents (Fig-
ure 1). Furthermore, it has been suggested that these highly
Owing to the importance of the triarylethene unit in or-
ganic synthesis, various methods have been developed in
recent years to create this unit.[5] Recently, Itami et al. re-
ported the effective synthesis of triarylethene-based conju-
gated dendrimers through the Pd-catalyzed double Mizo-
roki–Heck reaction and sequential mono-Suzuki–Miyaura
coupling reaction.[6] Shimizu et al. described a highly
stereocontrolled two-step approach to 1,1,2-triaryl-1-alk-
enes by using Suzuki coupling reactions.[7] Based on our
interest in coupling reactions,[8] herein we describe the facile
synthesis of novel triarylethene molecules by a one-step
double Suzuki–Miyaura coupling reaction. Note that we
found this catalytic system to be effective, ligand-free, and
reusable, which renders it attractive from the viewpoint of
“green chemistry”.
Results and Discussion
Our early attempts to apply liganded Pd[9a] or Cu cata-
lysts[9b] to the coupling of 1-(2,2-dibromovinyl)benzene and
phenylboronic acid were unsuccessful and many byproducts
were obtained in addition to the domino-coupled product,
as evidenced by LC–MS (Scheme 1). Other Pd-catalyzed
coupling reactions performed in the absence of ligand at
room temperature also failed to yield the desired triaryl-
ethene products when carrying out the reactions in com-
monly used solvents, including dimethylformamide, di-
methyl sulfoxide, toluene, water and acetonitrile.[10] How-
ever, to our surprise, the Pd-catalyzed coupling reaction
performed in PEG-400 afforded the desired triarylethene
product in 23% yield (Table 1, entry 1).[11] Poly(ethylene
glycol) (PEG) solvents can be recycled and meet environ-
mental concerns: They provide a facile way of immobilizing
the catalyst in a liquid phase simply by dissolving it in what
Figure 1. Biologically active molecules containing the triarylethyl-
ene moiety.
[a] Key Laboratory of Organic Synthesis of Jiangsu Province,
College of Chemistry, Chemical Engineering and Materials
Science, Soochow University,
Suzhou 215123, P. R. China
Fax: +86-512-65880403
E-mail: jcmao@suda.edu.cn
[b] Department of Chemistry, University of Basel,
Spitalstrasse 51, 4056 Basel, Switzerland
Supporting information for this article is available on the
WWW under http://dx.doi.org/10.1002/ejoc.201200577.
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FULL PAPER
is a nonvolatile and low toxic liquid.[12] Water also has clear tries 3–5 vs. 1 and 2).[14] We speculate that the active cata-
advantages over usual organic solvents in being easily avail- lytic species may comprise in situ generated palladium
able and very economic. From an industrial point of view, nanoparticles in PEG.[15] In general, the reaction was more
the use of a two-phase system allows an easy separation of favorable when the volume of water was more than the vol-
the products from the water-soluble organometallic catalyst ume of PEG. Further addition of water led to a very rapid
by simple phase separation.[13]
decrease of the yields (Table 1, entry 6). Screening of bases
(Table 1, entries 7–12) also led to further improvements and
suggested that inorganic bases are better than an organic
base with K3PO4 giving the best performance (73% yield,
Table 1, entry 8). Screening of the palladium source
(Table 1, entries 13 and 14) revealed that Pd(OAc)2 was the
best. In an attempt to increase the yield, various commer-
cially available ligands, such as PPh3, tBu3P, and PCy3, were
employed in the coupling reactions, but without success
(Table 1, entries 15–17). An increased catalyst loading also
failed to increase the yield (Table 1, entry 18), as did a range
of additives, including LiCl, tBuOOH, TBAB, and KI
(Table 1, entries 19–22).
These optimized conditions were next applied to the cou-
pling reaction between 1,1-dibromo-1-alkene and a wide
range of arylboronic acids bearing either electron-donating
or -withdrawing groups, as summarized in Table 2. The
coupling of 4-methylphenylboronic acid gave an increased
yield of 76% and was clearly better than the coupling with
2-methylphenylboronic acid, which gave a yield of 53%
(Table 2, entries 2 and 3). Excellent yields (92–99%) were
achieved in the coupling reactions of methoxy-substituted
arylboronic acids (Table 2, entries 4–6). Note that electron-
withdrawing groups such as F, Cl, and CF3 gave low yields
of triarylethene (Table 2, entries 7–9). The coupling of 3-
carboxyphenylboronic acid did not afford the desired prod-
uct (Table 2, entry 10). Good yields of triarylethene were
obtained from the coupling of formylphenylboronic acid
(Table 2, entries 11 and 12). A yield of 50% of the corre-
sponding product was obtained when 1-naphthalene-
boronic acid was used as the substrate (Table 2, entry 13).
3-Pyridineboronic acid was not suitable for the coupling,
giving only traces of the product (Table 2, entry 14). How-
ever, the coupling of 3-thienylboronic acid gave 63% yield
of the desired product (Table 2, entry 15).
Scheme 1. Coupling reaction between 1,1-dibromo-1-alkene and
phenylboronic acid using various catalytic systems.
Table 1. Suzuki–Miyaura coupling reaction between 1-(2,2-di-
bromovinyl)benzene and phenylboronic acid using Pd catalysts.[a]
Entry
Pd cat.
(mol-%)
Base
Solvent
Yield
[%][b]
1
2
3
4
5
6
7
8
Pd(OAc)2 (4)
Pd(OAc)2 (4)
Pd(OAc)2 (4)
Pd(OAc)2 (4)
Pd(OAc)2 (4)
Pd(OAc)2 (4)
Pd(OAc)2 (4)
Pd(OAc)2 (4)
Pd(OAc)2 (4)
Pd(OAc)2 (4)
Pd(OAc)2 (4)
Pd(OAc)2 (4)
Pd(dba)2 (4)
PdCl2 (4)
Pd(OAc)2 (4)
Pd(OAc)2 (4)
Pd(OAc)2 (4)
Pd(OAc)2 (4)
Pd(OAc)2 (4)
Pd(OAc)2 (4)
Pd(OAc)2 (4)
Pd(OAc)2 (4)
K2CO3
K2CO3
K2CO3
K2CO3
K2CO3
K2CO3
Na2CO3
K3PO4
Cs2CO3
tBuOK
KOH
PEG-400
H2O
23
0
PEG/H2O (1:3)
PEG/H2O (3:1)
PEG/H2O (1:1)
PEG/H2O (1:5)
PEG/H2O (1:3)
PEG/H2O (1:3)
PEG/H2O (1:3)
PEG/H2O (1:3)
PEG/H2O (1:3)
PEG/H2O (1:3)
PEG/H2O (1:3)
PEG/H2O (1:3)
PEG/H2O (1:3)
PEG/H2O (1:3)
PEG/H2O (1:3)
PEG/H2O (1:3)
PEG/H2O (1:3)
PEG/H2O (1:3)
PEG/H2O (1:3)
PEG/H2O (1:3)
48
39
42
trace
68
73
58
68
41
32
50
57
67
66
42
67
58
50
NR
21
9
10
11
12
13
14
15[c]
16[d]
17[e]
18
19[f]
20[g]
21[h]
22[i]
Et3N
K3PO4
K3PO4
K3PO4
K3PO4
K3PO4
K3PO4
K3PO4
K3PO4
K3PO4
K3PO4
We then addressed the possibility of using various 1,1-
dihalo-1-alkenes, as reported in Table 3. Because 4-meth-
oxylphenylboronic acid had been proved to be the best sub-
strate, the coupling reactions of 4-methoxylphenylboronic
acid with various 1,1-dihalo-1-alkenes were investigated. In
general, moderate-to-good yields of the desired products
were obtained (54–92%, Table 3, entries 1–7). Most notably,
when the challenging substrate 1,1-dichloro-1-alkene was
used, we still managed to isolate the triphenylethene prod-
[a] Reaction conditions: Pd cat. (0.03 mmol), 1-(2,2-dibromovinyl)-
benzene (0.3 mmol), phenylboronic acid (0.7 mmol), base
(0.6 mmol), additive (0.3 mmol), solvent (2 mL), 40 °C, 24 h, air.
[b] Isolated yield based on 1,1-dibromo-1-alkene. [c] PPh3 (8 mol-
%) as the ligand. [d] tBu3P (8 mol-%) as the ligand. [e] Pcy3 (8 mol- uct in 38% yield (Table 3, entry 8). The coupling reactions
%) as the ligand. [f] LiCl (1 equiv.) as the additive. [g] tBuOOH
between 1-(2,2-dibromovinyl)-2-fluorobenzene and various
(1 equiv.) as the additive. [h] TBAB (1 equiv.) as the additive. [i] KI
arylboronic acids gave yields in the range of 55–88%
(1 equiv.) as the additive.
(Table 3, entries 9–13). However, the use of (2,2-dibromo-
Thus, taking encouragement from our initial results, we vinyl)cyclohexane as the substrate led to only a trace of the
investigated the effect of PEG on the double Suzuki– desired product (Table 3, entry 14).
Miyaura reaction in water. Optimization of the reaction
This facile methodology was applied to the coupling re-
condition revealed that mixed solvents of PEG and water action between phenylpropiolic acid and 1,4-bis(2,2-di-
gave better results than PEG or water alone (Table 1, en- bromovinyl)benzene to prepare 1,4-bis(2,2-diphenylvinyl)-
2
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Palladium-Catalyzed Synthesis of Triarylethene-Based Molecules
Table 2. Double Suzuki–Miyaura coupling reactions between 1-
(2,2-dibromovinyl)benzene and arylboronic acid using Pd(OAc)2.[a]
Table 3. Scope of the Pd-catalyzed double Suzuki–Miyaura cou-
pling reactions between various 1,1-dihalo-1-alkenes and aryl-
boronic acids.[a]
[a] Reaction conditions: Pd(OAc)2 (0.012 mmol), 1-(2,2-dibromovi-
nyl)benzene (0.3 mmol), arylboronic acid (0.7 mmol), K3PO4
(0.6 mmol), PEG-400/H2O (3:1; 2 mL), 40 °C, 24 h, air. [b] Isolated
yield based on 1,1-dibromo-1-alkene.
benzene in 52% yield, as shown in Scheme 2. Considering
that many emitting dye molecules contain a DPVB sub-
structure, this versatile approach provides a novel and prac-
tical route to the synthesis of these useful compounds.[16]
If equal amounts of substrates were employed in the re-
action only 43% yield of 1,1,2-triphenylethene was ob-
tained and not the mono-Suzuki product (Scheme 3).
[a] Reaction conditions: Pd(OAc)2 (0.012 mmol), 1,1-dihalo-1-alk-
ene (0.3 mmol), arylboronic acid (0.7 mmol), K3PO4 (0.6 mmol),
PEG-400/H2O (3:1; 2 mL), 40 °C, 24 h, air. [b] Isolated yield based
on 1,1-dihalo-1-alkene (average of two runs).
was derived from consecutive Suzuki–Miyaura cross-cou-
Then the Pd-catalyzed coupling reaction between 1-(2,2- pling using these two different arylboronic acids (44%
dibromovinyl)benzene, phenylboronic acid, and 3-formyl- yield), in contrast to the finding of Shen.[10a] In addition, it
phenylboronic acid was performed, as shown in Scheme 4. can be seen that the corresponding boronic acid bearing a
LC–MS showed that, except for the expected double Suzuki formyl substituent reacts faster than benzeneboronic acid
products of these two arylboronic acids, the main product (24 vs. 7% yield).[17]
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Y. Zhu, P. Sun, H. Yang, L. Lu, H. Yan, M. Creus, J. Mao
FULL PAPER
Scheme 2. Pd-catalyzed coupling reaction between 1,4-bis(2,2-dibromovinyl)benzene and phenylboronic acid in the mixed solvent of PEG
and water.
Scheme 3. Pd-catalyzed coupling reaction between equal amounts of 1-(2,2-dibromovinyl)benzene and phenylboronic acid in the mixed
solvent of PEG and water.
Scheme 4. Pd-catalyzed coupling reaction between 1-(2,2-dibromovinyl)benzene and two different arylboronic acids in the mixed solvent
of PEG and water.
Scheme 5 further illustrates the versatility of this novel of the catalytic system was very simple, only requiring the
synthetic approach: From the simple 1-(2,2-dibromovinyl)- addition of diethyl ether to the reaction and decanting the
benzene to its triarylethene derivative, only two steps were upper layer.
performed to obtain the desired bis(1,1-dibromo-1-alkene)
in good yield, its four activated bromide atoms remaining
untouched for possible further applications.
Conclusions
Effective Pd-catalyzed double coupling reactions be-
tween various 1,1-dihalo-1-alkenes and arylboronic acids
were performed in aqueous solution to prepare useful tri-
arylethene compounds under mild conditions. In general,
the desired products were obtained in good-to-excellent
yields. Note that this protocol is ligand-free, additive-free,
inert-gas-free, and reusable, thus representing a practical
and low-cost method for the preparation of triarylethene-
based molecules. Thus, it is potentially useful for the syn-
Scheme 5. Synthesis of various 1,1-dibromo-1-alkene derivatives.
thesis of materials[18] and biologically active molecules. Fur-
Reagents and conditions: a) 4-formylphenylboronic acid, Pd-
ther investigations toward such applications are in progress.
(OAc)2, K3PO4, PEG-400/H2O (1:3), 40 °C, 24 h; b) CBr4, PPh3,
CH2Cl2, room temp.
Experimental Section
General: All reactions were carried out under argon. Solvents were
Finally, this ligand-free catalytic system could be reused
four times with good catalytic activity, which is potentially
useful for large-scale processes. Furthermore, the recovery dried and degassed by the standard methods and all aryl halides
4
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Palladium-Catalyzed Synthesis of Triarylethene-Based Molecules
were purchased from Aldrich or Alfa. Arylboronic acids and palla-
dium catalysts were purchased from Aldrich, Acros, or Alfa. 1,1-
Dihalo-1-alkenes were prepared according to ref.[19] Flash column
chromatography was performed on silica gel (300–400 mesh). Ana-
lytical TLC was performed with glass plates precoated with 200–
300 mesh silica gel impregnated with a fluorescent indicator
(254 nm). NMR spectra were recorded in CDCl3 with a Varian
Inova-400 NMR spectrometer (400 MHz) with TMS as an internal
reference. The products were characterized by comparison of 1H
and 13C NMR and TOF-MS data with the literature.
136.2, 136.2, 132.4, 132.3, 129.7, 129.5, 129.4, 128.6, 128.3, 127.2,
116.1, 115.8 ppm. HRMS (ESI+): calcd. for [C20H14F2]+ 292.1064;
found 292.1061.
1-Methoxy-3-[1-(3-methoxyphenyl)-2-phenylvinyl]benzene: 1H NMR
(400 MHz, CDCl3): δ = 7.23 (t, J = 6.4 Hz, 2 H), 7.16–7.10 (m, 3
H), 7.05 (d, J = 7.2 Hz, 2 H), 6.96 (s, 1 H), 6.93 (d, J = 8.4 Hz, 1
H), 6.88 (d, J = 8.4 Hz, 2 H), 6.85 (s, 1 H), 6.81 (t, J = 7.6 Hz, 1
H), 6.74 (s, 1 H), 3.78 (s, 3 H), 3.70 (s, 3 H) ppm. 13C NMR
(75 MHz, CDCl3): δ = 160.0, 159.7, 145.0, 142.4, 141.8, 137.4,
129.9, 129.8, 129.4, 128.6, 128.2, 127.1, 123.0, 120.4, 115.7, 113.6,
113.2, 113.1, 55.5, 55.4 ppm. HRMS (ESI+): calcd. for
[C22H20O2]+ 316.1463; found 316.1460.
General Procedure for Pd-Catalyzed Double Coupling Between Vari-
ous 1,1-Dihalo-1-Alkenes and Arylboronic Acids without Using Li-
gand: 1,1-Dihalo-1-alkene (0.3 mmol) was dissolved in mixed sol-
vent (PEG-400 0.5 mL and H2O 1.5 mL) and arylboronic acid
(0.7 mmol), palladium acetate (0.012 mmol), and potassium phos-
phate (0.6 mmol) were added. The reaction mixture was stirred at
40 °C for 24 h. After cooling to room temperature, the mixture was
diluted with water and the combined aqueous phases were ex-
tracted three times with ethyl acetate. The organic layers were com-
bined, dried with Na2SO4, and concentrated to yield the crude
product, which was further purified by silica gel chromatography
using petroleum ether and ethyl acetate as eluent to provide the
desired product.
1-Methoxy-2-[1-(2-methoxyphenyl)-2-phenylvinyl]benzene: 1H NMR
(400 MHz, CDCl3): δ = 7.23 (d, J = 6.4 Hz, 2 H), 7.12–7.07 (m, 4
H), 7.03 (d, J = 7.6 Hz, 2 H), 6.98 (t, J = 8.4 Hz, 1 H), 6.93 (d, J
= 4.4 Hz, 1 H), 6.89 (d, J = 6.4 Hz, 1 H), 6.86 (d, J = 9.2 Hz, 2
H), 6.82 (s, 1 H), 3.64 (s, 3 H), 3.49 (s, 3 H) ppm. 13C NMR
(75 MHz, CDCl3): δ = 157.5, 157.3, 138.3, 136.4, 133.6, 131.8,
131.4, 130.9, 129.0, 128.6, 128.5, 127.9, 126.7, 120.8, 120.7, 112.0,
111.6, 111.3, 56.0, 55.7 ppm. HRMS (ESI+): calcd. for
[C22H20O2]+ 316.1463; found 316.1463.
1
1-Methyl-4-[2-phenyl-1-(p-tolyl)vinyl]benzene: H NMR (400 MHz,
1
CDCl3): δ = 7.22 (d, J = 7.6 Hz, 2 H), 7.13–7.07 (m, 9 H), 7.04 (d,
J = 8.0 Hz, 2 H), 6.89 (s, 1 H), 2.38 (s, 3 H), 2.35 (s, 3 H) ppm.
13C NMR (75 MHz, CDCl3): δ = 142.7, 141.2, 138.0, 137.7, 137.6,
137.3, 130.5, 129.8, 129.6, 129.2, 128.2, 127.8, 127.4, 126.8, 21.6,
21.4 ppm. HRMS (ESI+): calcd. for [C22H20]+ 284.1565; found
284.1563.
1,1,2-Triphenylethene: H NMR (400 MHz, CDCl3): δ = 7.32–7.28
(m, 8 H), 7.21 (t, J = 3.6 Hz, 2 H), 7.12 (t, J = 7.2 Hz, 3 H), 7.03 (d,
J = 7.2 Hz, 2 H), 6.97 (s, 1 H) ppm. 13C NMR (75 MHz, CDCl3): δ
= 144.2, 142.0, 139.0, 137.7, 132.0, 131.2, 130.3, 129.8, 129.8, 129.6,
129.2, 129.1, 129.0, 128.4 ppm. HRMS (ESI+): calcd. for
[C20H16]+ 256.1252; found 256.1251.
1-[1-(Naphthyl)-2-phenylvinyl]naphthalene: 1H NMR (400 MHz,
CDCl3): δ = 8.45 (d, J = 8.4 Hz, 1 H), 7.95 (dd, J = 8.2, 3.6 Hz, 3
H), 7.85 (t, J = 8.4 Hz, 2 H), 7.77 (d, J = 7.2 Hz, 1 H), 7.66 (t, J
= 8.0 Hz, 2 H), 7.61–7.54 (m, 3 H), 7.50–7.45 (m, 3 H), 7.39 (d, J
= 7.6 Hz, 3 H), 7.29 (d, J = 8.0 Hz, 1 H), 7.25 (s, 1 H) ppm. 13C
NMR (75 MHz, CDCl3): δ = 138.7, 133.8, 133.5, 133.5, 133.1,
131.9, 130.6, 129.0, 128.7, 128.7, 128.6, 128.4, 128.2, 128.1, 127.1,
126.8, 126.7, 126.5, 126.2, 126.1, 125.6, 125.6, 123.7, 121.2, 94.6,
87.8 ppm.
4,4Ј-(2-Phenylethene-1,1-diyl)dibenzaldehyde: 1H NMR (400 MHz,
CDCl3): δ = 10.06 (s, 1 H), 10.03 (s, 1 H), 7.88 (dd, J = 12.9,
7.6 Hz, 4 H), 7.46 (d, J = 7.2 Hz, 2 H), 7.40 (d, J = 7.2 Hz, 2 H),
7.18 (s, 4 H), 7.06 (d, J = 4.8 Hz, 2 H) ppm. 13C NMR (75 MHz,
CDCl3): δ = 193.5, 193.3, 150.10, 147.9, 141.9, 137.7, 137.3, 137.1,
133.7, 132.8, 131.9, 131.5, 131.4, 129.9, 129.8, 129.5 ppm. HRMS
(ESI+): calcd. for [C22H16O2]+ 312.1150; found 312.1149.
3-[2-Phenyl-1-(thiophen-3-yl)vinyl]thiophene: 1H NMR (400 MHz,
CDCl3): δ = 7.35–7.29 (m, 3 H), 7.20–7.14 (m, 4 H), 7.05 (dd, J =
7.0, 6.3 Hz, 4 H), 6.96 (d, J = 4.8 Hz, 1 H) ppm. 13C NMR
(75 MHz, CDCl3): δ = 144.9, 140.3, 137.4, 132.2, 129.4, 128.5,
128.3, 127.7, 127.0, 126.2, 125.9, 125.8, 124.6, 123.1 ppm. HRMS
(ESI+): calcd. for [C16H12S2]+ 268.0380; found 268.0379.
1-Chloro-4-[1-(4-chlorophenyl)-2-phenylvinyl]benzene: 1H NMR
(400 MHz, CDCl3): δ = 7.30 (t, J = 8.0 Hz, 3 H), 7.22 (d, J =
8.4 Hz, 3 H), 7.17–7.11 (m, 5 H), 7.03 (d, J = 7.2 Hz, 2 H), 6.94
(s, 1 H) ppm. 13C NMR (75 MHz, CDCl3): δ = 141.8, 140.4, 138.6,
137.0, 133.8, 132.8, 132.1, 129.8, 129.3, 129.3, 129.1, 128.7, 128.4,
127.4 ppm. HRMS (ESI+): calcd. for [C20H14Cl2]+ 324.0473; found
324.0473.
3,3Ј-(2-Phenylethene-1,1-diyl)dibenzaldehyde: 1H NMR (400 MHz,
CDCl3): δ = 10.00 (s, 1 H), 9.56 (s, 1 H), 7.88 (d, J = 7.2 Hz, 1 H),
7.84 (d, J = 6.0 Hz, 2 H), 7.72 (s, 1 H), 7.56–7.49 (m, 4 H), 7.16–
7.11 (m, 4 H), 7.03–7.01 (m, 2 H) ppm. 13C NMR (75 MHz,
CDCl3): δ = 193.9, 193.7, 145.4, 142.4, 141.4, 138.6, 138.2, 138.2,
137.9, 137.8, 137.7, 135.1, 133.4, 132.4, 131.3, 131.2, 130.8, 130.7,
130.6, 130.2, 129.9, 129.2 ppm. HRMS (ESI+): calcd. for
[C20H16O2]+ 312.1150; found 312.1154.
4,4Ј-[2-(2-Chlorophenyl)ethene-1,1-diyl]bis(methoxybenzene):
1H
NMR (400 MHz, CDCl3): δ = 7.48 (d, J = 8.4 Hz, 1 H), 7.33 (d,
J = 8.4 Hz, 1 H), 7.29 (d, J = 8.4 Hz, 2 H), 7.05 (d, J = 7.6 Hz, 2
H), 6.95 (t, J = 8.8 Hz, 2 H), 6.87 (d, J = 8.4 Hz, 3 H), 6.78 (d, J
= 8.4 Hz,2 H), 3.83 (s, 1 H), 3.79 (s, 1 H) ppm. 13C NMR (75 MHz,
CDCl3): δ = 159.7, 159.2, 143.9, 136.8, 136.1, 134.7, 132.1, 131.3,
129.6, 127.9, 127.7, 126.1, 123.1, 114.4, 113.9, 113.8, 55.6,
55.4 ppm. HRMS (ESI+): calcd. for [C22H22ClO2]+ 350.1074;
found 350.1075.
4,4Ј-[2-(o-Tolyl)ethene-1,1-diyl]bis(methoxybenzene): 1H NMR
(400 MHz, CDCl3): δ = 7.48 (d, J = 7.6 Hz, 2 H), 7.28 (d, J =
8.4 Hz, 2 H), 7.12 (d, J = 7.6 Hz, 1 H), 7.01 (d, J = 8.4 Hz, 3 H),
6.90–6.84 (m, 4 H), 6.81 (s, 1 H), 3.83 (s, 3 H), 3.77 (s, 3 H), 2.31
(s, 3 H) ppm. 13C NMR (75 MHz, CDCl3): δ = 159.3, 159.1, 141.1,
136.8, 136.3, 135.2, 133.7, 133.2, 131.8, 129.5, 129.0, 128.9, 128.0,
126.4, 114.4, 114.2, 113.7, 55.5, 55.4 ppm. HRMS (ESI+): calcd.
for [C23H22O2]+ 330.1620; found 330.1626.
4,4Ј-[2-(p-tolyl)ethene-1,1-diyl]bis(methoxybenzene): 1H NMR
(400 MHz, CDCl3): δ = 7.47 (d, J = 8.4 Hz, 3 H), 7.25 (t, J =
6.0 Hz, 3 H), 7.12 (d, J = 8.0 Hz, 2 H), 6.85 (t, J = 8.4 Hz, 4 H),
1-Fluoro-4-[1-(4-fluorophenyl)-2-phenylvinyl]benzene: 1H NMR
(400 MHz, CDCl3): δ = 7.29 (s, 1 H), 7.25 (s, 1 H), 7.17–7.13 (m, 6.80 (s, 1 H), 3.83 (s, 3 H), 3.81 (s, 3 H), 2.26 (s, 3 H) ppm. 13C
5 H), 7.04–6.99 (m, 6 H), 6.89 (s, 1 H) ppm. 13C NMR (75 MHz, NMR (75 MHz, CDCl3): δ = 160.5, 160.3, 142.5, 138.2, 134.6,
CDCl3): δ = 164.3, 164.1, 161.0, 160.8, 140.7, 139.6, 139.6, 137.3,
133.2, 130.9, 130.4, 130.3, 129.4, 127.8, 115.8, 115.6, 115.1, 57.0,
Eur. J. Org. Chem. 0000, 0–0
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Y. Zhu, P. Sun, H. Yang, L. Lu, H. Yan, M. Creus, J. Mao
56.9, 56.8 ppm. HRMS (ESI+): calcd. for [C23H22O2]+ 330.1620; 3,3Ј-[2-(2-Fluorophenyl)ethene-1,1-diyl]dibenzaldehyde: 1H NMR
FULL PAPER
found 330.1616.
(400 MHz, CDCl3): δ = 10.01 (s, 1 H), 9.94 (s, 1 H), 7.87–7.83 (m,
3 H), 7.69 (s, 1 H), 7.59–7.46 (m, 5 H), 7.17 (s, 1 H), 7.02 (t, J =
9.6 Hz, 1 H), 6.83–6.75 (m, 2 H) ppm. 13C NMR (75 MHz,
CDCl3): δ = 192.4, 192.2, 161.1 (d,1JCF = 247.6 Hz), 143.6, 142.2,
140.6, 136.9 (d, 2JCF = 23.3 Hz), 136.6, 133.9, 131.9, 130.5 (d, 3JCF
= 2.6 Hz), 129.8, 129.6, 129.5, 129.4, 129.1, 128.2, 124.7, 124.5,
4,4Ј-[2-(4-Bromophenyl)ethene-1,1-diyl]bis(methoxybenzene):
1H
NMR (400 MHz, CDCl3): δ = 7.47 (d, J = 8.8 Hz, 1 H), 7.08 (d,
J = 8.4 Hz, 2 H), 6.95 (d, J = 8.4 Hz, 2 H), 6.89 (s, 2 H), 6.87 (d,
J = 2.4 Hz, 2 H), 6.85 (d, J = 2.8 Hz, 2 H), 6.83 (s, 1 H), 6.73 (s,
1 H), 3.83 (s, 3 H), 3.80 (s, 3 H) ppm. 13C NMR (75 MHz, CDCl3):
δ = 159.6, 142.9, 137.1, 136.3, 132.5, 131.8, 131.3, 131.2, 129.1,
128.0, 125.0, 120.2, 114.3, 113.8, 55.6, 55.5 ppm. HRMS (ESI+):
calcd. for [C22H19BrO2]+ 394.0568; found 394.0561.
2
123.8, 123.1, 115.8 (d, JCF = 21.8 Hz) ppm. HRMS: calcd. for
[C22H15FO2]+ 330.1056; found 330.1055.
2,2Ј-[2-(2-Fluorophenyl)ethene-1,1-diyl]bis(methoxybenzene):
1H
1H
NMR (400 MHz, CDCl3): δ = 7.33 (t, J = 8.0 Hz, 1 H), 7.22 (d, J
= 7.6 Hz, 2 H), 7.09 (d, J = 5.2 Hz, 2 H), 6.97 (t, J = 7.6 Hz, 2 H),
4,4Ј-[2-(2-Fluorophenyl)ethene-1,1-diyl]bis(methoxybenzene):
NMR (400 MHz, CDCl3): δ = 7.47 (d, J = 8.4 Hz, 1 H), 7.28 (s, 1
H), 7.10–7.03 (m, 3 H), 6.99–6.94 (m, 2 H), 6.90 (s, 1 H), 6.86–6.75
(m, 5 H), 3.83 (s, 1 H), 3.80 (s, 1 H) ppm. 13C NMR (75 MHz,
6.94–6.81 (m, 5 H), 6.76 (t, J = 7.2 Hz, 1 H), 3.67 (s, 3 H), 3.50 (s,
1
3 H) ppm. 13C NMR (75 MHz, CDCl3): δ = 160.8 (d, JCF
=
1
247.7 Hz), 157.5, 157.2, 138.2, 133.1, 131.7, 131.4, 130.9, 130.4,
CDCl3): δ = 161.2 (d, JCF = 247.5 Hz), 159.6, 159.2, 143.9, 136.6,
3
2
3
129.7 (d, JCF = 3.2 Hz), 128.8, 128.7, 128.2 (d, JCF = 25.3 Hz),
132.6, 131.8, 130.5 (d, JCF = 2.6 Hz), 129.4, 127.9, 126.1, 123.4
2
3
2
123.9, 123.3, 120.8, 120.7, 115.2 (d, JCF = 22.2 Hz), 112.0, 111.6,
(d, JCF = 3.1 Hz), 118.0, 115.4 (d, JCF = 22.1 Hz), 114.1, 113.8,
55.5, 55.4 ppm. HRMS (ESI+): calcd. for [C22H19FO2]+ 334.1369;
found 334.1368.
56.0, 55.7 ppm. HRMS: calcd. for [C22H19FO2]+ 334.1369; found
334.1371.
1H
NMR
4,4Ј-[2-(4-Chlorophenyl)ethene-1,1-diyl]bis(methoxybenzene):
1H
4,4Ј-(2-Phenylethene-1,1-diyl)bis(methoxybenzene):
(400 MHz, CDCl3): δ = 7.47 (d, J = 8.8 Hz, 1 H), 7.24 (d, J =
6.4 Hz, 1 H), 7.11 (t, J = 6.0 Hz, 4 H), 7.04 (d, J = 7.2 Hz, 2 H),
6.95 (d, J = 8.8 Hz, 1 H), 6.86 (d, J = 3.2 Hz, 2 H), 6.83 (t, J =
3.2 Hz, 3 H), 3.82 (s, 3 H), 3.80 (s, 3 H) ppm. 13C NMR (75 MHz,
CDCl3): δ = 160.9, 160.5, 143.4, 139.5, 138.1, 134.3, 133.3, 131.1,
130.5, 129.6, 128.0, 127.8, 115.6, 115.2, 57.0, 56.8 ppm. HRMS:
calcd. for [C22H20O2]+ 316.1463; found 316.1462.
NMR (400 MHz, CDCl3): δ = 7.47 (d, J = 8.4 Hz, 1 H), 7.24 (d,
J = 8.4 Hz, 2 H), 7.08 (d, J = 8.0 Hz, 3 H), 6.94 (t, J = 5.6 Hz, 3
H), 6.86–6.83 (m, 3 H), 6.75 (s, 1 H), 3.82 (s, 1 H), 3.80 (s, 1
H) ppm. 13C NMR (75 MHz, CDCl3): δ = 157.9, 157.6, 141.0,
134.9, 134.6, 130.1, 129.1, 127.4, 126.6, 126.2, 123.3, 112.7, 112.6,
112.1, 53.8, 53.7 ppm. HRMS (ESI+): calcd. for [C22H19ClO2]+
350.1074; found 350.1061.
4,4Ј-(2-Phenylethene-1,1-diyl)bis[(2,2-dibromovinyl)benzene]:
NMR (400 MHz, CDCl3): δ = 7.55–7.48 (m, 6 H), 7.31 (d, J =
8.4 Hz, 2 H), 7.20 (d, J = 7.6 Hz, 2 H), 7.15–7.13 (m, 3 H), 7.03
(s, 3 H) ppm. 13C NMR (75 MHz, CDCl3): δ = 143.3, 141.5, 140.6,
137.2, 136.8, 136.7, 134.7, 131.2, 130.8, 129.9, 129.6, 129.1, 128.7,
128.4, 127.9, 127.5, 90.0, 89.9 ppm. HRMS (ESI+): calcd. for
[C24H16Br4]+ 623.7945; found 623.7927.
1H 4,4Ј-[2-(2-Fluorophenyl)ethene-1,1-diyl]dibenzaldehyde: 1H NMR
(400 MHz, CDCl3): δ = 10.08 (s, 2 H), 7.91 (d, J = 7.6 Hz, 4 H),
7.52 (d, J = 7.6 Hz, 2 H), 7.42 (d, J = 8.0 Hz, 2 H), 7.32 (d, J =
11.6 Hz, 1 H), 7.24 (d, J = 5.2 Hz, 1 H), 7.08 (t, J = 10.4 Hz, 1 H),
6.90–6.81 (m, 2 H) ppm. 13C NMR (75 MHz, CDCl3): δ = 192.2,
1
192.1, 161.3 (d, JCF = 249.2 Hz), 148.4, 146.2, 142.8, 136.1 (d,
3
2
3JCF = 2.0 Hz), 131.5, 130.8 (d, JCF = 2.0 Hz), 130.4 (d, JCF
=
24.5 Hz), 130.1, 130.0, 128.8, 124.7, 124.6, 124.1, 124.0, 116.0 (d,
2JCF = 21.9 Hz) ppm. HRMS: calcd. for [C22H15FO2]+ 330.1056;
found 330.1058.
4,4Ј-(4-Phenylbuta-1,3-diene-1,1-diyl)bis(methoxybenzene):
1H
NMR (400 MHz, CDCl3): δ = 7.47 (d, J = 8.4 Hz, 2 H), 7.31 (d,
J = 7.6 Hz, 2 H), 7.28–7.24 (m, 3 H), 7.20 (t, J = 8.4 Hz, 2 H),
6.96–6.88 (m, 4 H), 6.84 (d, J = 8.8 Hz, 1 H), 6.75 (d, J = 11.2 Hz,
1 H), 6.69 (d, J = 14.0 Hz, 1 H), 3.87 (s, 3 H), 3.84 (s, 3 H) ppm.
13C NMR (75 MHz, CDCl3): δ = 160.9, 160.6, 139.4, 135.1, 134.2,
133.5, 130.5, 130.2, 129.4, 129.2, 128.9, 128.1, 127.9, 115.8, 115.3,
115.2, 57.0, 56.9 ppm. HRMS (ESI+): calcd. for [C22H19ClO2]+
342.1620; found 342.1615.
1,4-Bis(2,2-diphenylvinyl)benzene: 1H NMR (400 MHz, CDCl3): δ
= 7.37 (s, 1 H), 7.35–7.34 (m, 5 H), 7.33–7.32 (m, 8 H), 7.21 (t, J
= 3.6 Hz, 3 H), 7.01 (d, J = 8.0 Hz, 3 H), 6.93 (s, 1 H) ppm. 13C
NMR (75 MHz, CDCl3): δ = 137.7, 132.0, 130.8, 130.2, 129.8,
129.5, 129.2, 129.1 ppm. HRMS: calcd. for [C34H26]+ 434.2035;
found434.2032.
2,2Ј-(2-Phenylethene-1,1-diyl)bis(methylbenzene):
1H
NMR
Supporting Information (see footnote on the first page of this arti-
cle): Copies of the 1H NMR and 13C NMR spectra of all new
compounds.
(400 MHz, CDCl3): δ = 7.22–7.10 (m, 11 H), 6.97 (d, J = 7.6 Hz,
2 H), 6.68 (s, 1 H), 2.31 (s, 3 H), 2.03 (s, 3 H) ppm. 13C NMR
(75 MHz, CDCl3): δ = 145.0, 143.1, 141.9, 139.2, 137.9, 137.7,
137.4, 133.6, 132.6, 132.2, 131.5, 130.5, 129.7, 129.0, 128.7, 128.5,
127.6, 127.3, 22.5, 21.7 ppm. HRMS: calcd. for [C22H20]+ 284.1565;
found 284.1566.
Acknowledgments
1H
We are grateful for grants from the International S&T Cooperation
Program of Jiangsu Province (BZ2010048), the Scientific Research
Foundation for Returned Overseas Chinese Scholars, the State
Education Ministry, the Priority Academic Program Development
of Jiangsu Higher Education Institutions and the Key Laboratory
of Organic Synthesis of Jiangsu Province.
3,3Ј-[2-(2-Fluorophenyl)ethene-1,1-diyl]bis(methoxybenzene):
NMR (400 MHz, CDCl3): δ = 7.35 (t, J = 7.6 Hz, 1 H), 7.22 (d, J
= 8.0 Hz, 2 H), 7.12 (s, 1 H), 7.06 (s, 1 H), 6.99 (d, J = 10.0 Hz, 1
H), 6.95 (t, J = 7.6 Hz, 2 H), 6.90 (s, 1 H), 6.86–6.84 (m, 2 H), 6.80
(d, J = 3.6 Hz,1 H), 6.72 (s, 1 H), 3.78 (s, 3 H), 3.68 (s, 3 H) ppm.
13C NMR (75 MHz, CDCl3): δ = 160.4 (d, 1JCF = 248.0 Hz), 160.1,
3
2
160.0, 144.8, 143.1, 141.7, 130.8 (d, JCF = 2.9 Hz), 130.1 (d, JCF
3
= 19.0 Hz), 129.6, 128.9, 123.8 (d, JCF = 3.4 Hz), 123.2, 120.9,
[1] N. Shigetaka, A. Katsumi, K. Makoto, I. Kiyotaka, WO Pat.
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[2] R. E. Allen, E. R. Andrews, E. L. Schumann, C. H. Tilford,
U.S. Pat. 3031449, 1962.
3
120.5, 120.2, 115.6 (d, JCF = 22.1 Hz), 114.1, 114.0, 113.4, 113.2,
55.7, 55.6 ppm. HRMS: calcd. for [C22H19FO2]+ 334.1369; found
334.1368.
6
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Palladium-Catalyzed Synthesis of Triarylethene-Based Molecules
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Received: May 1, 2012
Published Online: ᭿
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© 0000 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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Date: 17-07-12 11:32:41
Pages: 8
Y. Zhu, P. Sun, H. Yang, L. Lu, H. Yan, M. Creus, J. Mao
FULL PAPER
Synthesis of Triarylethenes
Y. Zhu, P. Sun, H. Yang, L. Lu, H. Yan,
M. Creus, J. Mao* ........................... 1–8
Effective Palladium-Catalyzed Synthesis of
Triarylethene-Based Molecules in Aqueous
Solution
Keywords: Cross-coupling
Alkenes / Boronic acids / Palladium
/ Bromine /
Highly effective and selective Pd-catalyzed
coupling reactions of 1,1-dibromo-1-alk-
enes with various arylboronic acids have
been performed in aqueous solution under
mild conditions. The method is simple,
economic, and practical for the synthesis of
triarylethene-based compounds.
8
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