Chemistry Reference
In-Depth Information
Table 36 Desulfinylative
cross-coupling with
2-thienylsulfinates [
356
]
R
1
Ar
1
Yield (%)
benzo[
b
]
4-NCC
6
H
4
78
5-Me
4-NCC
6
H
4
64
4-Me
4-NCC
6
H
4
57
3-Me
4-NCC
6
H
4
27
H
4-NCC
6
H
4
71
H
3-NCC
6
H
4
65
H
2-NCC
6
H
4
84
H
4-F
3
CC
6
H
4
44
H
4-EtO
2
CC
6
H
4
64
H
1-naphthalenyl
49
H
4-MeOC
6
H
4
22
O
Et
3
P
Pd
Me
N
0.5 mol%
150,
THF, CsF, rt
Ph
Cl
O
+
Bu
3
Sn
R
1
R
1
80-91%
S
S
148
149
151
150
Scheme 59 Stille coupling of chlorothiophenes with organostannanes [
357
]
Table 37 Stille coupling of
chlorothiophenes with
organostannanes [
357
]
R
1
Yield
a
(%)
Chlorothiophene
H
2-Cl
88 (91)
H
3-Cl
80 (84)
CHO
5-Cl
91 (93)
a
GC yield in parentheses
in combination with the catalyst precursors palladium(II) chloride and phosphine
results in higher yields in almost all cases.
Stille Cross-Coupling in the Presence of a Phosphanyl-
-Ketoiminate Palladium
β
Catalyst
Another approach for the synthesis of biaryls is the Stille cross-coupling reaction.
For this, chlorothiophenes 148 can be coupled with tributyl(phenyl)stannanes 149
by means of a highly active phosphanyl-
-ketoiminate palladium complex 150
forming the arylated thiophenes 151 in high yields (Scheme
59
, Table
37
)[
357
].
It is noteworthy that the reaction works with unreactive, inexpensive, and readily
available chlorothiophenes 148 at room temperature.
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