Biomedical Engineering Reference
In-Depth Information
organocatalysi
s
+
RCHO
NH
NH
2
R
t
-Bu
S
MeO
Catalyst
:
i
-Bu
2
N
P
roduct:
H
H
NAc
O
N
Me
Ph
H
CHEt
2
94
95
(81%, ee = 93%
)
i
-Pr
i
-Pr
CO
2
Et
MeO
CO
2
Et
i
-Pr
NAc
O
O
O
OH
P
H
i
-Pr
NO
2
i
-Pr
i
-Pr
96
97
(98%, ee = 96%)
SCHEME 6.18
Organocatalytic Pictet-Spengler reactions.
SiPh
3
O
O
O
OH
P
SiPh
3
100
(2 mol%)
HN
N
O
O
MS 4 Å
Toluene, rt
86%
+
Me
CHO
I
Me
I
Me
N
H
H
Me
98
99
101
(ee = 89%)
O
O
1. Pd(PPh
3
)
4
PhOH,
t-
BuOK
THF, reflux, 30 min
N
N
Me
2. TFA, CH
2
Cl
2
rt, 2 h
I
Me
N
H
H
Boc
Me
H
O
Me
O
Arboricine
(
103
)
102
SCHEME 6.19
Total synthesis of arboricine via Pictet-Spengler reaction.
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