Chemistry Reference
In-Depth Information
CO
2
Et
Pd(OAc)
2
, BQ,
KHCO
3
, O
2
MeO
MeO
CO
2
H
CO
2
H
CO
2
Et
3.8
3.7
Scheme 3.7
CO
2
Et
Pd(OAc)
2
, PhCO
3
t
-Bu
O
CO
2
Et
O
3.9
3.10
Scheme 3.8
CO
2
n
-Bu
CO
2
n
-Bu
Pd(OAc)
2
, Cu(OAc)
2
H
H
3.11
3.12
Scheme 3.9
CO
2
Et
CO
2
Et
Pd(OAc)
2
, TsOH, BQ, Ac
2
O
N
NH
CONMe
2
3.14
3.13
O
NMe
2
C-H activation
nucleophilic
attack
[Pd]
[Pd]
O
CO
2
Et
H
NH
NMe
2
O
NMe
2
3.17
3.15
CO
2
Et
1
3
insertion
η
→ η
[Pd]
NH
3.16
NMe
2
O
Scheme 3.10
1
-palladium intermediate
As with the classical Heck reaction (Section 9.2.9), if a diene is employed, the
3
-complex
3.17
and be trapped by a nucleophile
3.16
generated by CH activation and insertion can become a
(Scheme 3.10) to give a heterocycle
3.14
.
9
A pioneering application of C-H activation to natural-product synthesis is in a synthesis of ibogamine
3.24
(Scheme 3.11).
10
An asymmetric Diels-Alder reaction set up the chirality. The chirality was controlled by the
use of a chiral auxiliary on the diene
3.18
. Reductive amination then connected the Diels-Alder product
3.19
to an indole moiety. Palladium-catalysed cyclization then generated the bicyclic alkene
3.23
. In this reaction,
