Chemistry Reference
In-Depth Information
Table 9.3
Asymmetric hydroformylation of cis -4,7-dihydro-1,3-dioxepines 41a,b using carbohydrate ligands.
catalyst (0.25 mol%): Rh(acac)(CO) 2 /ligand* (ratio 1:2)
H 2 , CO, toluene
O
O
CHO
O
R 3
R 3
R 3
R 3
R 3
R 3
*
+
O
O
O
41
42
43
(undesired)
R 3 = H
R 3 = H
R 3 = H
R 3 = H
a
b
a
b
R 2
R 1
Substrate
O
O
O
O
Entry
Ligand
R 3
R 3
Yield 42 (%)
Yield 41 (%)
ee (%)
=
O
O
R 2
R 1
1
R 3
=
H
59
—
40 (
+
)
D- xylo
O
O
O
P
P
O
O
O
4b
O
R 1
=
R 2
=
t Bu
R 3
2
=
Me
86
—
51 (S)
O
O
Me
Me
O
D- ribo
O
P
O
O
11b
3
R 3
=
H
48
26
30 (
+
)
O
R 1
=
R 2
=
t Bu
O
O
O
P
Me
Me
O
12a
R 3
4
=
H
54
—
<
5
R 1
=
R 2
=
H
D- gluco
O
12b
R 1 = R 2 = t Bu
Me
O
5
O
R 3
=
H
85
—
23 (
+
)
P
O
P
O
O
O
12c
6
R 3 = H
75
—
18 (+)
O
R 1
=
t Bu, R 2
=
OMe
O
Me
12d
Me
7
R 3
=
H
83
—
22 (
+
)
R 1
=
TMS, R 2
=
H
L- ido
O
P
Me
O
O
O
13b
O
8
O
R 3
=
H
90
—
35 (
+
)
P
O
R 1
=
R 2
=
t Bu
O
O
Me
Me
 
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