Chemistry Reference
In-Depth Information
(Ph
3
P)
4
Pd, Et
3
N
EtO
2
C
EtO
2
C
EtO
2
C
I
EtO
2
C
5.167
5.168
Scheme 5.47
If a suitably placed nucleophilic atom is present, it can coordinate to the palladium atom after inser-
tion to give a cyclic intermediate
5.174
.
47
This can be followed by reductive elimination to give a useful
synthesis of indoles
5.170
, known as the Larock indole synthesis (Scheme 5.48),
48
and other heterocycles
(Scheme 5.49).
49
5.1.10.2 Trisubstituted Alkenes
Trisubstituted alkenes are usually poor substrates for Heck chemistry, and must almost always be used in
an intramolecular way. Treatment of the phenolic ether
5.177
with a palladium catalyst resulted in ox-
idative addition and insertion, leading to a stable
1
-intermediate
5.179
as it has no available
-hydrogen
Me
Pd(OAc)
2
, PPh
3
,
LiCl, KOAc
I
Me
+
Ph
Ph
N
Ac
NHAc
5.169
5.170
reductive
elimination
oxidative
addition
Me
I
L
n
Pd
Ph
N
Ac
NHAc
Me
5.169
5.170
PdL
n
I
Ph
PdL
n
NHAc
N
5.171
Me
coordination
Ph
Ac
5.174
HI
coordination
Me
Ph
Me
Ph
PdL
n
I
NH
PdL
n
I
NHAc
insertion
5.172
5.173
Ac
Scheme 5.48
