Chemistry Reference
In-Depth Information
R
X
R
R
R
R
R
O
P
P
P
P
P
P
R
R
R
R
DuXantPhos
21
:R=Me,X=S
22
:R=H,X=
i
-Pr
22
23
O
S
R
R
P
S
O
R
R
O
P
P
P
P
P
P
P
Fe
O
R
R
R
R
ButiPhane
UlluPhos
MPL-SegPhos
KePhos
F
F
O
F
F
A
R
R
Cl
Cl
F
F
A=
P
P
O
F
F
F
F
O
R
R
X=O,NMe,N
n
Bu, NBn,
N(CH
2
)
2
COOMe, N-(
R
)-
CH(Ph)Me, N-(
S
)-CH(Ph)Me,
CH
2
,S,N(Me)N(Me)
X
Cat
AS
ium M series
O
Figure 7.7.
BPE and DuPhos analogues with modifi cations on the linker.
hydrogenated. We try to summarize the results from the standard substrates and high-
light the applications in the syntheses of more complex molecules and industrial prod-
ucts. When making comparison, the readers should be aware that many of the
hydrogenations summarized were carried out under different conditions.
7.3.1. Asymmetric Hydrogenation of Olefi ns
7.3.1.1. α-Dehydroamino Acids
The great importance of chiral α - amino acids and
their derivatives in pharmaceutical, agricultural, and biologic chemistry has made their
synthesis a central theme in organic chemistry. Asymmetric hydrogenation of α - and
β-dehydroamino acids has been demonstrated as one of the most successful synthetic
approaches. Since the very fi rst achievements by Knowles et al. [4] and Kagan and
Dang [5], asymmetric hydrogenation of dehydroamino acids has now become a typical
