Chemistry Reference
In-Depth Information
O
O
NH
NH
Pd(OAc)
2
(5 mol%)
AgOAc (1.1 equiv)
neat, 110 °C, 10 min
N
N
+
Me
H
Me
I
OMe
OMe
92% yield
(4 equiv)
Me
NH
O
Me
NH
O
Pd(OAc)
2
(5 mol%)
AgOAc (1.1 equiv)
neat, 150 °C
N
+
N
H
I
Br
Br
72% yield
(4 equiv)
Scheme 12.40 Directing group-assisted Pd-catalyzed C
sp
3
-H direct arylation.
Br
2
O
O
O
Pd(OAc)
2
t
BuCN
DCM
Me
Me
Me
Me
Me
Me
N
N
H
Br
60 °C
-78 °C
Pd
II
NC
t
Bu
Pd
IV
N
N
N
H
t
BuCN
Br
1
2
85% yield
1. MePhI, acetone, rt
2. HI
O
O
Me
Me
Me
H
H
N
N
Me
Me
9%
31 %
Me
Scheme 12.41
Synthesis and reactivity of palladacycle complexes.
O
O
O
Pd(OAc)
2
-AcOH
-
AcO H
Me
Me
Me
Me
Me
Me
N
N
H
Pd
II
Pd
II
N
N
N
H
H
L
n
OAc
L
n
RI
O
O
reductive
eli
mination
O
Me
Me
Me
Me
Me
Me
H
N
N
I
R
I
N
Pd
II
L
n
N
Pd
IV
N
R
L
n
R
Scheme 12.42 Proposed mechanism for Pd-catalyzed C
sp
3
-H direct arylation.
the C
sp
3
-H bond where a Pd
IV
species was not observed, indicating that
probably 1 may be the reactive intermediate in the reaction. Based on these
studies, they proposed a Pd
II
/Pd
IV
cycle to be operative (Scheme 12.42).
He and Chen extended this methodology for the arylation of the g-C
sp
3
-H
bond in various aliphatic amines using picolinamide as the directing
group.
73
They demonstrated that the regioselective outcome of the reaction
depends on the relative conformation of the C-H bond with respect to the
Search WWH ::
Custom Search