Chemistry Reference
In-Depth Information
D-
gluco
R
1
R
1
R
2
Ph
O
O
O
O
O
O
Ph
P
P
X =
P
X
O
O
O
Ph
N
h
R
1
R
1
R
2
R
a
R
1
= R
2
=
t
Bu
b
R
1
=
t
Bu; R
2
= OMe
d
(
S
)
ax
; R
1
= H
e
(
R
)
ax
; R
1
= H
64
R= Ph
65
R=
i
Pr
66
R=
t
Bu
67
R= Me
c
R
1
= SiMe
3
; R
2
= H
f
(
R
)
ax
; R
1
= SiMe
3
g
(
S
)
ax
; R
1
= SiMe
3
Figure 8.12
Phosphite/phosphinite-oxazoline ligands
64
-
67.
Ph
COOEt
Ph
Ph
Ph
Ph
64c
; 85% Conv
99% (
R
)
64c
; 100% Conv
>99% (
R
)
64c
; 100% Conv
>99% (
R
)
64a
; 100% Conv
95% (
S
)
OH
OAc
Et
t
Bu
Ph
Ph
Ph
Ph
64a
; 100% Conv
92% (
R
)
64a
; 100% Conv
94% (
R
)
64c
; 100% Conv
99% (
S
)
64c
; 100% Conv
97% (
S
)
Figure 8.13
Summary of the best results for the hydrogenation of several minimally
functionalized olefins using ligands
64
-
67.
obtained at low catalyst loadings with simple disubstituted olefins [43]
(Figure 8.13).
8.5
P-S Donors
Concerning the use of P-S carbohydrate derivatives in asymmetric hydrogenation,
thioether-phosphinite ligands (P-SR; R
Ph,
i
Pr, and Me), containing a furano-
side backbone
, 68-70
(Figure 8.14), provide rhodium and iridium catalysts for the
=
D-
xylo
PPh
2
RS
68
69
70
R = Ph
O
O
R =
i
Pr
R = Me
O
O
Figure 8.14
Thioether-phosphinite ligands
68
-
70.
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