Chemistry Reference
In-Depth Information
O
CO
2
Me
(
S
,
S
)-
127
Cl
N
HCOOH / Et
3
N
A
OH
CO
2
Me
Cl
N
HO
2
C
(
R
)-
B
S
CO
2
Me
Cl
N
L-699,392
Scheme 7.14.
Synthesis of L-699,392 via transfer hydrogenation.
O
OH
CF
3
CF
3
(
S
,
S
)-
35
2-Propanol or
HCO
2
H/NEt
3
(
S
)-
B
A
OCH
3
CH
3
HN
O
N
O
CF
3
(
S
)-MA20565
Scheme 7.15.
Synthesis of (
S
) - MA20565 via asymmetric hydrogenation.
zirconocene catalysts [363] have been proved effective to certain substrates in this area.
Some success has also been achieved in the asymmetric hydrogenation of functionalized
C=N double bonds, such as
N
-acyl hydrozones, sulfonimides, and
N
- diphenylphosphinyl
ketimines. Very recently, both the Zhang [364] and Zhou [365,366] groups explored this
type of substrates with Pd catalysts. Superior enantioselectivities have been achieved
with a wide range of substrates, providing great promise to this transformation.
