Biomedical Engineering Reference
In-Depth Information
O
O
1. Conditions
A
or
B
2. MeSO
3
H
N
NH
N
Br
N
N
H
H
MeSO
3
H
RWJ444772
24
25
O
O
Markó's conditions (
A
): Pd
2
(dba)
3
, BINAP,
t-
BuONa, THF, 60°C, 9 h (90%)
Santos' conditions (
B
): PdCl
2
, [bmin]PF
6
,K
2
CO
3
, MW, dioxane, 180°C, 30 min (69%)
SCHEME 3.11
RWJ444772 synthesis by Marko and Santos.
MeO
Me
MeO
Me
TFA
N
TFA
N
OMe
Me
OMe
OMe
OMe
OMe
OMe
Me
Me
Me
Ancisheynine
Ancistrocladinium A
Pd
2
(dba)
3
BINAP
t-
BuOK
PhMe
reflux
OR
OMe
MeO
Me
NH
2
X
MeO
Me
2 steps
Ancistrocladiniums
A and B
HN
Me
Ar
OMe
X'
OMe
26
27
28
For ancistrocladinium A: X = H, X' = Br, OR = OMe (63%)
For ancistrocladinium B: X = Br, X' = H, OR = OCH
2
OMe (49%)
SCHEME 3.12
Synthesis of ancisheynine and ancistrocladinium A and B.
Recently, Bringmann and coworkers published an elegant route to ancisheynine
alkaloid [30], as well as antileishmanial active ancistrocladinium A and B [31], by
using a Buchwald-Hartwig amination for direct
N
-arylations of bromonaphthalenes
(Scheme 3.12).
3.2.5.3.
Intramolecular Amidation In the total synthesis of
the potent
cholecystokinin antagonist, (
)-asperlicin, Snider and coworkers used a Pd-catalyzed
intramolecular amidation as a key step to build imidazolidinone
30
in 48% yield
(Scheme 3.13) [32].
3.2.5.4. Indole Synthesis Indoles are versatile heterocyclic building blocks
present in a plethora of natural products and pharmaceuticals [33]. A number of very
practical, modular, and elegant protocols involving Pd catalysis to afford indole
derivatives
were first published in 1999 by Buchwald and
coworkers [34] and 10 years later by Barluenga and coworkers [35] (Scheme 3.14).
34
,
36
, and
39
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