N-heterocyclic carbene/Pd(II)/1-methylimidazole complex catalyzed suzuki-miyaura coupling reaction of aryl chlorides in water

Article abstract of DOI:10.1055/s-0030-1260169

A well-defined N-heterocyclic carbene (NHC)/palladium chloride/imidazole complex exhibited high catalytic activity in the Suzuki-Miyaura coupling reactions of aryl or heteroaryl chlorides performed in water. Under optimal conditions, all reactions gave the desired coupling products in good to high yields. Georg Thieme Verlag Stuttgart New York.

Full text of DOI:10.1055/s-0030-1260169

3
138
PAPER
N-Heterocyclic Carbene/Pd(II)/1-Methylimidazole Complex Catalyzed
Suzuki–Miyaura Coupling Reaction of Aryl Chlorides in Water
S
X
uzuki–Miyaura
C
i
oupling
a
of
A
ryl
C
-
hlorides
Xi n Water ia Zhou, Li-Xiong Shao*
College of Chemistry and Materials Engineering, Wenzhou University, Chashan University Town, Wenzhou, Zhejiang Province 325035,
P. R. of China
Fax +86(577)88373111; E-mail: Shaolix@wzu.edu.cn
Received 21 May 2011; revised 28 June 2011
Abstract: A well-defined N-heterocyclic carbene (NHC)/palladi-
iPr
um chloride/imidazole complex exhibited high catalytic activity in
the Suzuki–Miyaura coupling reactions of aryl or heteroaryl chlo-
rides performed in water. Under optimal conditions, all reactions
gave the desired coupling products in good to high yields.
iPr
Cl
Pd
Cl
Me
N
N
N
N
iPr
Key words: N-heterocyclic carbenes, palladium, imidazole, Suzu-
ki–Miyaura coupling, water
iPr
Figure 1 NHC-Pd(II)-Im complex 1
Transition-metal-catalyzed reactions between organobo-
ranes and organic electrophiles, now named Suzuki–
Miyaura coupling, have become a versatile method for
In initial studies, a model reaction of chlorobenzene (2a;
0.5 mmol) with 4-methoxyphenylboronic acid (3a; 0.6
mmol) catalyzed by NHC-Pd(II)-Im complex 1 (2.0
mol%) was carried out in water (2.0 mL) at 80 °C for 12
hours to establish the best base. For each of the bases
screened, the reactions took place smoothly to give the de-
sired coupling product 4a in good to high yields (Table 1),
however, t-BuOK gave the best result (Table 1, entry 2).
Therefore, the optimal reaction conditions were estab-
lished as NHC-Pd(II)-Im complex 1 (2.0 mol%) as the
catalyst, t-BuOK (2.0 equiv) as the base, and water (2.0
mL) as the solvent at 80 °C.9
1
carbon–carbon bond formations. During the past years,
much effort, mainly focused on finding supporting
ligands, has been made to improve the efficiency of these
reactions, especially for those involving aryl chlorides,
2
which are low-cost and easily available. Recently, great
progress had been made in the chemistry of N-heterocy-
clic carbenes (NHCs) and their transition-metal complex-
3
es. Nowadays, many NHC-palladium complexes have
been shown to be good catalyst in the Suzuki–Miyaura
4
coupling reactions of aryl chlorides.
,10
In contrast to common organic solvents, water is non-tox-
ic, non-flammable, cheap, and easily available. A variety Table 1 Optimization of the Complex 1 Catalyzed Reaction of 2a
of organic transformations have been successfully with 3a in Water
5
achieved in water. Yet, despite the advantageous fea-
tures, only a few papers on the Suzuki–Miyaura coupling
Cl
B(OH)2
OMe
of aryl chlorides catalyzed by NHC-palladium complexes
6
in neat water have been reported to date. Recently, we
complex 1 (2.0 mol%)
+
have synthesized a well-defined NHC-palladium chlo-
base, H O, 80 °C, 12 h
2
ride-1-methylimidazole [NHC-Pd(II)-Im] complex 1 de-
2a
.
rived from PdCl , IPr HCl, and 1-methylimidazole. It was
OMe
2
3
a
4
a
found that the complex was an efficient catalyst in the am-
7
ination reactions of aryl chlorides (Figure 1). These
Entrya
Yield (%)b
Base
results prompted us to further investigate other applica-
tions of this complex. In our continuing investigations on
Suzuki–Miyaura coupling reactions performed in neat
1
2
3
4
5
NaOH
t-BuOK
KOH
87
95
78
68
80
79
8
water, we found that NHC-Pd(II)-Im complex 1 was an
efficient catalyst in Suzuki–Miyaura coupling of aryl/het-
eroaryl chlorides performed in neat water. Herein, we
wish to report these results in detail.
KHCO3
Na CO
2
3
6
K CO
2
3
a
SYNTHESIS 2011, No. 19, pp 3138–3142
x
x.
x
x
.
2
0
1
1
Reaction conditions: 2a (0.5 mmol), 3a (0.6 mmol), 1 (2.0 mol%),
Advanced online publication: 10.08.2011
DOI: 10.1055/s-0030-1260169; Art ID: H53711SS
Georg Thieme Verlag Stuttgart · New York
base (2.0 equiv), H O (2.0 mL), 80 °C, 12 h.
Isolated yield.
2
b
©

PAPER
Suzuki–Miyaura Coupling of Aryl Chlorides in Water
3139
The optimized reaction conditions were then applied to a Table 2 Complex 1 Catalyzed Coupling Reactions of Aryl Chlo-
rides 2 with Boronic Acids 3 under the Optimized Conditions
variety of arylboronic acids and aryl chlorides to investi-
(
continued)
gate the generality of the method. As can be seen from
Table 2, all reactions occurred smoothly to give the corre-
sponding coupling products in moderate to excellent
yields within 12–24 hours. It seems that the reactions in-
volving 4-methoxyphenyl chloride (2b) gave the products
in somewhat lower yields (Table 2, entries 1, 2, 6, 13, and
R1
R2
Cl
B(OH)2
complex 1 (2.0 mol%)
KOt-Bu (2.0 equiv)
+
H2O, 80 °C, 12–24 h
R2
R1
2
3
1
4), except for the reaction of 2b with 2-methylphenylbo-
ronic acid (3d), which gave product 4c in good yield
Table 2, entry 3). Sterically hindered substituents on ei- Entrya 2 (R1)
4
3 (R2)
Time Product Yield
(
b
(
h)
(%)
ther substrates 2 or 3 had almost no effect on the reactions.
For instance, reactions involving substrates 2c, 2e, 2f and
2
i with 3-methoxy, 3-methyl, 2-methyl, and 2,6-dimethyl
groups on the phenyl rings, respectively, all gave the ex- 12
pected products in good to high yields (Table 2, entries 4,
2i
24
4k
96
B(OH)2
7
, 8, 11, and 12). 2-Methylphenylboronic acid (3d) also
3
f
gave products 4c, 4j, 4r, and 4s in high yields, respective-
ly (Table 2, entries 3, 11, 19, and 20). Reactions of het-
eroaryl chlorides such as 2-chloropyridine (2j), 3-
chloropyridine (2k) and 2-chlorothiophene (2l) with 4-
methoxyphenylboronic acid (3a), 2-methylphenylboronic 14
acid (3d) and 1-naphthylboronic acid (3f) also gave the
corresponding coupling products in good to high yields
within 12–24 hours (Table 2, entries 15–17 and 19–24). 3-
Chlorothiophene (2m) was found not to be a good partner
and only 55% yield of the corresponding product 4q was
obtained (Table 2, entry 18).
1
3
2b
2b
12
12
12
4l
51
65
99
B(OH)2
3g
3f
4m
4n
1
5
3a
N
N
Cl
Cl
2
j
1
1
6
7
3a
3a
12
24
4o
4p
99
87
Table 2 Complex 1 Catalyzed Coupling Reactions of Aryl Chlo-
rides 2 with Boronic Acids 3 under the Optimized Conditions
2
k
Cl
S
R1
R2
Cl
B(OH)2
2l
complex 1 (2.0 mol%)
KOt-Bu (2.0 equiv)
Cl
+
H2O, 80 °C, 12–24 h
18
3a
12
4q
55
R2
S
R1
2
3
2
m
4
1
9
2j
3d
3d
3f
12
12
12
12
12
24
4r
4s
99
99
93
99
96
81
Entrya 2 (R1)
3 (R2)
Time Product Yield
b
20
2k
2j
(
h)
(%)
69
67
86
86
95
69
99
99
99
93
2
2
2
1
2
3
4
4t
1
2
3
4
5
6
7
8
9
0
2b (4-OMe)
2b
3b (H)
3c (4-Me)
3d (2-Me)
3b
24
24
12
24
12
12
12
24
12
24
4a
4b
4c
4d
4e
4f
2k
2k
2j
3f
4u
4v
4w
3b
3b
2b
2
2c (3-OMe)
2d (4-NO2)
2b
a
Reaction conditions: 2 (0.5 mmol), 3 (0.6 mmol), 1 (2.0 mol%),
t-BuOK (2.0 equiv), H O (2.0 mL), 80 °C for the listed time.
Isolated yield.
3b
2
b
3e (4-F)
3a (4-OMe)
3a
2e (3-Me)
2f (2-Me)
2g (4-Ac)
2h (4-CHO)
4g
4c
4h
4i
In summary, the well-defined NHC-Pd(II)-Im complex 1,
derived from readily available starting materials IPr HCl,
PdCl , and 1-methylimidazole, showed high catalytic ac-
tivity in the Suzuki–Miyaura coupling reactions of aryl
chlorides in water under mild conditions. Under the opti-
mal conditions, the corresponding coupling products can
be achieved in good to high yields. It is worth noting that
the NHC-Pd complex catalyzed Suzuki–Miyaura cou-
.
2
3a
1
1
3b
2
i (2,6-
1
3d
24
4j
96
Me C H )
2
6
3
Synthesis 2011, No. 19, 3138–3142 © Thieme Stuttgart · New York

3
140
X.-X. Zhou, L.-X. Shao
PAPER
pling reactions of aryl chlorides performed in water were Compound 4e14
Pale-yellow solid; yield: 94.8 mg (95%).
significantly improved with respect to the previous re-
port, and similar yields were achieved compared with the
6
1
H NMR (500 MHz, CDCl ): d = 7.45 (t, J = 7.5 Hz, 1 H, Ar), 7.50
3
1
2
(
dd, J = J = 7.5 Hz, 2 H, Ar), 7.62 (d, J = 7.5 Hz, 2 H, Ar), 7.68 (d,
best systems known in the literature under non-aqueous
4
J = 8.5 Hz, 2 H, Ar), 7.95 (d, J = 8.5 Hz, 2 H, Ar).
conditions.
1
3
C NMR (125 MHz, CDCl ): d = 124.1, 127.4, 127.8, 128.9, 129.1,
3
1
38.8, 147.1, 147.6.
1H and 13C NMR spectra were recorded with Bruker AV-II 300
MHz or Bruker AV-III 500 MHz spectrometers; samples were ana-
Compound 4f13
White solid; yield: 69.5 mg (69%).
lyzed as solutions in CDCl with tetramethylsilane (TMS) as an in-
3
ternal standard; coupling constants (J values) are given in Hz.
Commercially obtained reagents were used without further purifica-
tion. Flash column chromatography was carried out using Huanghai
1
H NMR (300 MHz, CDCl ): d = 3.84 (s, 3 H, OCH ), 6.97 (dd, J =
3
3
6
.6, 2.1 Hz, 2 H, Ar), 7.06–7.12 (m, 2 H, Ar), 7.45–7.51 (m, 4 H,
Ar).
3
00–400 mesh silica gel under increased pressure.
1
3
C NMR (75 MHz, CDCl ): d = 55.3, 114.2, 115.5 (d, J
=
=
3
C–F
Complex 1 Catalyzed Suzuki–Miyaura Coupling Reaction;
General Procedure
2
3
1.0 Hz), 128.0, 128.1 (d, JC–F = 8.3 Hz), 132.8, 136.9 (d, JC–F
.0 Hz), 159.1, 162.1 (d, JC–F = 243.8 Hz).
When aryl chloride is liquid: Under an N atmosphere, arylboronic
2
acid 3 (0.6 mmol), NHC-Pd(II)-Im 1 (2.0 mol%), t-BuOK (2.0
Compound 4g15
Pale-yellow solid; yield: 98.1 mg (99%).
equiv), and H O (2.0 mL) were added to a Schlenk reaction tube,
2
then aryl chloride 2 (0.5 mmol) was added. The mixture was stirred
at 80 °C for 12–24 h (Table 2) then extracted with EtOAc, dried
over anhydrous Na SO , filtered, and purified by flash column chro-
1
H NMR (500 MHz, CDCl ): d = 2.41 (s, 3 H, CH ), 3.84 (s, 3 H,
3
3
OCH ), 6.96 (d, J = 7.0 Hz, 2 H, Ar), 7.12 (d, J = 7.0 Hz, 1 H, Ar),
7
3
2
4
.29–7.36 (m, 3 H, Ar), 7.52 (d, J = 7.0 Hz, 2 H, Ar).
matography to give the pure products.
1
3
C NMR (125 MHz, CDCl ): d = 21.5, 55.3, 114.1, 123.8, 127.4,
3
When aryl chloride is solid: Under an N atmosphere, aryl chloride
2
1
27.5, 128.1, 128.6, 133.9, 138.3, 140.8, 159.1.
2
(0.5 mmol), arylboronic acid 3 (0.6 mmol), NHC-Pd(II)-Im 1 (2.0
mol%), t-BuOK (2.0 equiv), and H O (2.0 mL) were added to a
Schlenk reaction tube. The mixture was stirred at 80 °C for 12–24 h
2
Compound 4h16
White solid; yield: 111.9 mg (99%).
(
Table 2) then extracted with EtOAc, dried over anhydrous Na SO ,
2 4
1H NMR (500 MHz, CDCl
OCH ), 7.00 (d, J = 9.0 Hz, 2 H, Ar), 7.58 (d, J = 9.0 Hz, 2 H, Ar),
.65 (d, J = 8.5 Hz, 2 H, Ar), 8.01 (d, J = 8.5 Hz, 2 H, Ar).
): d = 2.63 (s, 3 H, CH ), 3.87 (s, 3 H,
3
filtered, and purified by flash column chromatography to give the
pure products.
3
3
7
Compound 4a11
White solid; yield: 87.4 mg (95%).
13
C NMR (125 MHz, CDCl ): d = 26.6, 55.4, 114.4, 126.6, 128.4,
3
1
28.9, 132.3, 135.3, 145.4, 159.9, 197.7.
1
H NMR (300 MHz, CDCl ): d = 3.85 (s, 3 H, OCH ), 6.96 (dd, J =
3
3
Compound 4i17
6
.9, 2.4 Hz, 2 H, Ar), 7.28–7.33 (m, 1 H, Ar), 7.39–7.44 (m, 2 H,
Ar), 7.51–7.57 (m, 4 H, Ar).
Colorless oil; yield: 84.8 mg (93%).
1
3
1
C NMR (75 MHz, CDCl ): d = 55.3, 114.2, 126.6, 126.7, 128.1,
H NMR (500 MHz, CDCl ): d = 7.40 (t, J = 7.5 Hz, 1 H, Ar), 7.48
3
3
1
2
1
28.7, 133.8, 140.8, 159.1.
(dd, J = J = 7.5 Hz, 2 H, Ar), 7.63 (d, J = 7.5 Hz, 2 H, Ar), 7.75 (d,
J = 8.0 Hz, 2 H, Ar), 7.95 (d, J = 8.0 Hz, 2 H, Ar), 10.05 (s, 1 H,
CHO).
Compound 4b12
White solid; yield: 66.5 mg (67%).
13
C NMR (125 MHz, CDCl ): d = 127.3, 127.7, 128.4, 129.0, 130.2,
3
1
H NMR (300 MHz, CDCl ): d = 2.38 (s, 3 H, CH ), 3.84 (s, 3 H,
135.2, 139.7, 147.2, 191.9.
3
3
OCH ), 6.96 (dd, J = 6.6, 2.1 Hz, 2 H, Ar), 7.22 (d, J = 8.1 Hz, 2 H,
3
Compound 4j18
Ar), 7.45 (d, J = 8.1 Hz, 2 H, Ar), 7.51 (dd, J = 6.6, 2.1 Hz, 2 H,
Ar).
Colorless oil; yield: 94.1 mg (96%).
1
3
1H NMR (500 MHz, CDCl
3 H, CH ), 7.00–7.28 (m, 7 H, Ar).
C NMR (75 MHz, CDCl ): d = 21.0, 55.2, 114.1, 126.5, 127.9,
3
): d = 1.94 (s, 6 H, 2 × CH ), 1.97 (s,
3
3
1
29.4, 133.7, 136.3, 137.9, 158.9.
3
1
3
C NMR (125 MHz, CDCl ): d = 19.4, 20.3, 126.0, 126.9, 127.0,
3
Compound 4c13
Colorless oil; yield: 84.9 mg (86%).
1
27.2, 128.8, 129.9, 135.6, 135.8, 140.5, 141.1.
1
Compound 4k19
White solid; yield: 111.4 mg (96%).
H NMR (300 MHz, CDCl ): d = 2.27 (s, 3 H, CH ), 3.84 (s, 3 H,
3
3
OCH ), 6.94 (dd, J = 6.9, 1.8 Hz, 2 H, Ar), 7.21–7.26 (m, 6 H, Ar).
3
1
3
1H NMR (500 MHz, CDCl
(m, 6 H, Ar), 7.45–7.56 (m, 2 H, Ar), 7.85–7.91 (m, 2 H, Ar).
C NMR (75 MHz, CDCl ): d = 20.5, 55.2, 113.5, 125.7, 126.9,
3
): d = 1.90 (s, 6 H, 2 × CH ), 7.17–7.35
3
3
1
29.9, 130.2, 130.3, 134.3, 135.4, 141.5, 158.5.
1
3
C NMR (125 MHz, CDCl ): d = 20.4, 125.4, 125.7, 125.8, 126.0,
3
Compound 4d14
Colorless oil; yield: 79.2 mg (86%).
1
1
26.4, 127.2, 127.25, 127.31, 128.3, 131.7, 133.7, 137.0, 138.7,
39.6.
1
H NMR (300 MHz, CDCl ): d = 3.85 (s, 3 H, OCH ), 6.87–6.91
m, 1 H, Ar), 7.12–7.20 (m, 2 H, Ar), 7.31–7.38 (m, 2 H, Ar), 7.40–
3
3
Compound 4l20
(
7
.45 (m, 2 H, Ar), 7.57–7.60 (m, 2 H, Ar).
White solid; yield: 60.0 mg (51%).
1
3
1H NMR (500 MHz, CDCl
J = 8.0 Hz, 2 H, Ar), 7.43–7.49 (m, 2 H, Ar), 7.64 (d, J = 7.5 Hz,
C NMR (75 MHz, CDCl ): d = 55.2, 112.6, 112.8, 119.6, 127.1,
3
): d = 3.84 (s, 3 H, OCH ), 7.00 (d,
3
3
1
27.4, 128.7, 129.7, 141.0, 142.7, 159.9.
Synthesis 2011, No. 19, 3138–3142 © Thieme Stuttgart · New York

PAPER
H, Ar), 7.70 (d, J = 8.5 Hz, 1 H, Ar), 7.82–7.88 (m, 3 H, Ar), 7.97
Suzuki–Miyaura Coupling of Aryl Chlorides in Water
3141
2
Compound 4t22
(
s, 1 H, Ar).
Pale-yellow liquid; yield: 95.4 mg (93%).
1
3
1
C NMR (125 MHz, CDCl ): d = 55.3, 114.3, 125.0, 125.4, 125.6,
H NMR (500 MHz, CDCl ): d = 7.31–7.33 (m, 1 H, Ar), 7.47–7.63
3
3
1
1
26.2, 127.6, 128.0, 128.3, 128.4, 132.3, 133.6, 133.7, 138.1,
59.2.
(m, 5 H, Ar), 7.79–7.82 (m, 1 H, Ar), 7.93 (d, J = 8.5 Hz, 2 H, Ar),
8.12 (d, J = 8.0 Hz, 1 H, Ar), 8.81 (d, J = 5.0 Hz, 1 H, Ar).
1
3
C NMR (125 MHz, CDCl ): d = 121.9, 125.0, 125.2, 125.5, 125.8,
Compound 4m12
White solid; yield: 76.1 mg (65%).
3
1
26.4, 127.4, 128.3, 128.8, 131.1, 133.9, 136.3, 138.4, 149.4, 159.2.
1
Compound 4u23
Pale-yellow liquid; yield: 101.3 mg (99%).
H NMR (500 MHz, CDCl ): d = 3.88 (s, 3 H, OCH ), 7.01–7.03
3
3
(
m, 2 H, Ar), 7.39–7.51 (m, 6 H, Ar), 7.83 (d, J = 8.5 Hz, 1 H, Ar),
7
.89 (d, J = 8.5 Hz, 1 H, Ar), 7.92 (d, J = 8.5 Hz, 1 H, Ar).
1
H NMR (500 MHz, CDCl ): d = 7.41–7.57 (m, 5 H, Ar), 7.80–7.83
3
1
3
C NMR (125 MHz, CDCl ): d = 55.3, 113.7, 125.4, 125.7, 125.9,
(m, 2 H, Ar), 7.92 (t, J = 8.5 Hz, 2 H, Ar), 8.69 (dd, J = 5.0, 1.5 Hz,
1 H, Ar), 8.77 (d, J = 2.0 Hz, 1 H, Ar).
3
1
26.1, 126.9, 127.3, 128.2, 131.1, 131.8, 133.1, 133.8, 139.9, 158.9.
1
3
C NMR (125 MHz, CDCl ): d = 123.1, 125.25, 125.34, 126.1,
Compound 4n13
White solid; yield: 91.6 mg (99%).
3
1
1
26.5, 127.4, 128.4, 128.5, 131.5, 133.8, 136.3, 136.4, 137.3, 148.5,
50.6.
1
H NMR (500 MHz, CDCl ): d = 3.86 (s, 3 H, OCH ), 7.00 (d,
3
3
J = 8.5 Hz, 2 H, Ar), 7.15–7.18 (m, 1 H, Ar), 7.67–7.71 (m, 2 H,
Ar), 7.95 (d, J = 8.5 Hz, 2 H, Ar), 8.65 (d, J = 4.5 Hz, 1 H, Ar).
Compound 4v23
Colorless liquid; yield: 74.3 mg (96%).
1
3
1
C NMR (125 MHz, CDCl ): d = 55.3, 114.1, 119.8, 121.4, 128.1,
H NMR (500 MHz, CDCl ): d = 7.35–7.50 (m, 4 H, Ar), 7.57–7.60
3
3
1
32.0, 136.6, 149.5, 157.1, 160.4.
(m, 2 H, Ar), 7.87–7.89 (m, 1 H, Ar), 8.59 (dd, J = 4.5, 1.5 Hz, 1 H,
Ar), 8.85 (d, J = 2.0 Hz, 1 H, Ar).
Compound 4o13
White solid; yield: 91.3 mg (99%).
13
C NMR (125 MHz, CDCl ): d = 123.5, 127.1, 128.1, 129.1, 134.4,
3
1
36.7, 137.8, 148.3, 148.4.
1
H NMR (500 MHz, CDCl ): d = 3.86 (s, 3 H, OCH ), 7.01 (dd,
3
3
J = 6.5, 2.0 Hz, 2 H, Ar), 7.33 (dd, J = 8.0, 5.0 Hz, 1 H, Ar), 7.52
Compound 4w22
(
dd, J = 7.0, 2.0 Hz, 2 H, Ar), 7.83 (dt, J = 8.0, 2.0 Hz, 1 H, Ar),
Colorless liquid; yield: 62.9 mg (81%).
8
.54 (dd, J = 5.0, 1.5 Hz, 1 H, Ar), 8.81 (d, J = 2.0 Hz, 1 H, Ar).
1
H NMR (500 MHz, CDCl ): d = 7.20–7.23 (m, 1 H, Ar), 7.40–7.49
3
1
3
C NMR (125 MHz, CDCl ): d = 55.3, 114.5, 123.5, 128.2, 130.2,
(m, 3 H, Ar), 7.71–7.74 (m, 2 H, Ar), 7.99–8.01 (m, 2 H, Ar), 8.69–
8.70 (m, 1 H, Ar).
3
1
33.8, 136.2, 147.8, 147.9, 159.8.
1
3
C NMR (125 MHz, CDCl ): d = 120.5, 122.0, 126.9, 128.7, 128.9,
Compound 4p13
White solid; yield: 82.6 mg (87%).
3
1
36.7, 139.4, 149.6, 157.4.
1
H NMR (500 MHz, CDCl ): d = 3.83 (s, 3 H, OCH ), 6.91 (dd,
3
3
Supporting Information for this article is available online at
J = 6.5, 2.0 Hz, 2 H, Ar), 7.04 (dd, J = 5.0, 4.0 Hz, 1 H, Ar), 7.19–
http://www.thieme-connect.com/ejournals/toc/synthesis.
7
.21 (m, 2 H, Ar), 7.53 (dd, J = 6.5, 2.0 Hz, 2 H, Ar).
1
3
C NMR (125 MHz, CDCl ): d = 55.3, 114.3, 122.1, 123.8, 127.2,
3
1
27.3, 127.9, 144.3, 159.2.
Acknowledgment
Compound 4q21
White solid; yield: 52.4 mg (55%).
Financial support from the start-up fund of Wenzhou University is
greatly acknowledged. Xia-Xia Zhou thanks Mr. Yi-Qiang Tang for
his kind discussions, and Mr. Lei Zhu for his kind help in preparing
the revised version.
1
H NMR (500 MHz, CDCl ): d = 3.84 (s, 3 H, OCH ), 6.94 (d,
3
3
J = 9.0 Hz, 2 H, Ar), 7.34–7.38 (m, 3 H, Ar), 7.53 (d, J = 9.0 Hz,
2
H, Ar).
1
3
C NMR (125 MHz, CDCl ): d = 55.3, 114.2, 118.9, 126.0, 126.2, References
3
1
27.6, 128.8, 142.0, 158.9.
(1) (a) Miyaura, N.; Yamada, K.; Suzuki, A. Tetrahedron Lett.
1
9
1
979, 3437. (b) Miyaura, N.; Suzuki, A. Chem. Rev. 1995,
5, 2457. (c) Suzuki, A. J. Organomet. Chem. 1999, 576,
47. (d) Miyaura, N. J. Organomet. Chem. 2002, 653, 54.
Compound 4r13
Colorless liquid; yield: 83.9 mg (99%).
1
H NMR (500 MHz, CDCl ): d = 2.36 (s, 3 H, CH ), 7.23–7.30 (m,
(e) Miyaura, N. Top. Curr. Chem. 2002, 219, 11.
(f) Miyaura, N. Metal-Catalyzed Cross-Coupling Reactions,
2nd ed.; de Meijere, A.; Diederich, F., Eds.; Wiley-VCH:
Weinheim, 2004, Chap. 2, 41–124. (g) Suzuki, A. Chem.
Commun. 2005, 4759. (h) Alonso, F.; Beletskaya, I. P.; Yus,
M. Tetrahedron 2008, 64, 3047. (i) Molander, G. A.;
Canturk, B. Angew. Chem. Int. Ed. 2009, 48, 9240.
3
3
4
H, Ar), 7.40 (d, J = 5.0 Hz, 2 H, Ar), 7.72–7.75 (m, 1 H, Ar), 8.70
(
d, J = 5.0 Hz, 1 H).
1
3
C NMR (125 MHz, CDCl ): d = 20.2, 121.6, 124.1, 125.8, 128.2,
3
1
29.6, 130.7, 135.7, 136.1, 140.4, 149.2, 160.1.
Compound 4s13
Pale-yellow liquid; yield: 84.0 mg (99%).
(
2) (a) Phan, N. T. S.; Van Der Sluys, M.; Jones, C. W. Adv.
Synth. Catal. 2006, 348, 609. (b) Andersen, N. G.; Keay,
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Cornils, B.; Herrmann, W. A., Eds.; VCH: New York, 1996.
(d) Parshall, G. W.; Ittel, S. D. Homogeneous Catalysis, 2nd
1
H NMR (500 MHz, CDCl ): d = 2.27 (s, 3 H, CH ), 7.22 (d,
3
3
J = 7.0 Hz, 1 H, Ar), 7.26–7.36 (m, 4 H, Ar), 7.64–7.66 (m, 1 H,
Ar), 8.58–8.60 (m, 2 H, Ar).
1
3
C NMR (125 MHz, CDCl ): d = 20.3, 123.0, 126.1, 128.1, 129.8,
3
1
30.5, 135.6, 136.4, 137.5, 138.1, 148.1, 149.9.
Synthesis 2011, No. 19, 3138–3142 © Thieme Stuttgart · New York

3
142
X.-X. Zhou, L.-X. Shao
PAPER
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1
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2
(
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(
4
OMe
(
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Cl
B(OH)2
complex 1 (2.0 mol%)
(
KOH (2.0 equiv)
+
H2O, t-BuOH (X equiv)
8
0 °C,12 h
2a
OMe
2
010, 29, 6343. (c) Snead, D. R.; Inagaki, S.; Abboud,
4a
3
a
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Yield (%)
0
1
78
93
2
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Scheme 1
(
(
(
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(
(
(
(
(
(
(
(
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(
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Synthesis 2011, No. 19, 3138–3142 © Thieme Stuttgart · New York