Chemistry Reference
In-Depth Information
Novel synthesis of an indole skeleton
40
was developed by Mori and others
(Scheme 5.11) [15f,g]. Enantioselective allylic amination of
37
with
N
- sulfonated
ortho
- bromoaniline
38
in the presence of Pd
2
(dba)
3
· CHCl
3
and (
S
) - BINAPO followed
by Heck cyclization of
39
afforded chiral indoline
40
. Total syntheses of (
−
) - tubifoline,
(
−
) - dehydrotubifoline, and (
−
)-strychnine were achieved from
39
.
R
R
Ts
Pd
2
(dba)
3
·CHCl
3
R
Br
N
O
O
Pd (0)
(
S
)-BINAPO
+
N
Ts
DMF
O
NHTs
Br
H
37
38
39
(75%, 84% ee)
40
(R = CH
2
OTBDMS)
N
N
N
H
N
H
H
H
N
N
O
O
H
(
−
)-Strychnine
(
−
)-Tubifoline
(
−
)-Dehydrotubifoline
Scheme 5.11.
Trost and Aponick developed the palladium-catalyzed dynamic kinetic asymmetric
transformation (DYKAT) reaction of
meso
- and
dl
- 1,2 - divinylethylene carbonate
41
(Scheme 5.12) [15i]. This palladium-catalyzed DYKAT methodology using ligand
43
gave amino alcohol
42
as a single stereoisomer in 99% ee. Synthesis of
Epi
(+) - FR900482
was achieved from
42
[15l] .
[Pd(allyl)Cl]
2
HO
O
O
O
Ligand
43
O
+
HN
N
O
Na
2
CO
3
O
CH
2
Cl
2
O
dl
+
meso
41
42
(72%, 99% ee)
O
2
O
OH
O
O
OH
NH
HN
O
O
NH
N
PPh
2
Ph
2
P
H
Epi
(
+
)-FR900482
Ligand
43
Scheme 5.12.
