Chemistry Reference
In-Depth Information
OCH
3
OCH
3
H
H
N
N
N
NH
N
NH
CF
3
CF
3
N
N
O
O
120
119
CF
3
CF
3
R
Bu
t
Bu
t
N
N
F
3
C
CH
3
N
R=
122
S
Bu
t
121
CF
3
R
Bu
t
Figure 8A.7.
Other organocatalysts, such as
119
[130] ,
120
[130] ,
121
[131] , and
122
[132] , were
also employed in the asymmetric conjugate addition of malonates to nitroalkenes
(Fig. 8A.7 ).
1,3-Diketones and malononitriles were also employed in asymmetric conjugate addi-
tion reaction. Deng and others [133] reported that
123
was an effi cient catalyst in the
conjugate addition of
α
- substituted
β
- ketoesters to
α
,
β
- unsaturated ketones (Scheme
8A.65 ).
O
O
O
O
O
123
(1 mol %)
100% yield
97% ee
+
O
t
Bu
CH
3
CH
2
Cl
2
O
t
Bu
O
OH
H
3
C
OR
N
123
R=
N
H
Scheme 8A.65.
8A.3.6. Conjugate Addition of Amino Acid Derivatives
Corey et al. [134] employed
O
(9) - allyl -
N
- 9 - anthracenylmethylcinchon idinium bromide
124
as a catalyst in the conjugate addition of
N
- (diphenylmethylene)glycine
tert
- butyl
ester to several Michael acceptors. Since then, the classical procedure was modifi ed
