Chemistry Reference
In-Depth Information
R
1
B(OH)
2
R
1
[Pd(C
3
H
5
)Cl]
2
/
66
,
xylene, K
2
CO
3
, 130 °C
+
42-96%
S
X
S
67
64
65
R
2
R
1
R
2
[Pd(C
3
H
5
)Cl]
2
/
66
,
xylene, K
2
CO
3
, 130 °C
+
40-100%
B(OH)
2
S
68
X
S
70
R
1
69
Ph
2
P
P
Ph
2
PPh
2
Ph
2
P
66
Scheme 29 Suzuki-Miyaura coupling reactions of 3- and 2-thienylboronic acids with aryl
halides [
171
]
Table 17 Suzuki-Miyaura coupling reactions of 3- and 2-thienylboronic acids with aryl halides
[
171
]
Boronic acid
R
1
R
2
Ratio(substrate/catalyst)
a
Yield
b
(%)
X
68
COMe
-
Br
250:1
77 (82)
68
COMe
-
Br
1000:1
(55)
68
CHO
-
Br
250:1
81 (90)
68
CHO
-
Br
1000:1
(45)
68
CN
-
Br
250:1
85 (96)
68
CN
-
Br
1000:1
(77)
68
OMe
-
Br
250:1
84 (97)
68
OMe
-
Br
1000:1
(42)
64
H
H
I
100:1
82 (96)
64
H
H
Br
50:1
(47)
64
OMe
H
Br
50:1
81
64
H
Me
Br
20:1
87 (100)
64
H
Me
Br
50:1
(40)
a
Substrate/catalyst ratio based on aryl halide
b
Isolated yields; GC and NMR yields in parentheses
a base. 2- and 3-Thienylboronic acids can be obtained by the reaction via the
corresponding thienyllithiums [
169
,
170
].
The Suzuki-Miyaura coupling of 3-thienylboronic acid 64 with aryl bromides 65 is
possible with extremely low catalyst loadings of only 0.1% using the catalytic system
