Chemistry Reference
In-Depth Information
Table 4.16
Reactions of (S,S)-22 and various p-substituted benzaldehydes using Ac
2
O instead of SiO
2
in step 2
CO
2
t
Bu
TMG (
1
)
(1.1 equiv)
Ac
2
O
(2.2 equiv)
Bn
N
X
adduct
+
26
S
)-22
+
THF
25
o
C , 5 h
(step 1)
CHCl
3
rt
(step 2)
CHO
X
25
Run
X
Step 2, time (h)
25
(%)
26
(%)
Cis
(ee)
Trans
(ee)
Trans/cis
Total
1
OBu
0.5
3
64 (92)
96
67
65
2
OMe
0.5
4
77 (91)
95
81
65
3
Me
1.5
45 (90)
31 (93)
41
76
90
4
H
3
58 (86)
22 (88)
28
80
100
5
Cl
17
59 (86)
33 (84)
36
92
not purified
6
CO
2
Me
17.5
52 (79)
28 (72)
35
80
69
