Biomedical Engineering Reference
In-Depth Information
R= Me, Et
O
PPh
2
Fe
PPh
2
R
3
R
H
N
R
N
1
[Au(
c
-HexNC)
2
]BF
4
(1 mol%)
R
CO
2
Me
OH
hydrolysis
COOH
R
O
N
N
CO
2
Me
CH
2
Cl
2
, rt, 20 h
NH
2
C
83-100%
2
4
(up to 97% ee)
5
SCHEME 4.1
under acidic conditions could then be implemented to deliver the corresponding
a
-amino-
b
-hydroxy carboxylic acid
.
Since then, this elegant and efficient procedure has been successfully employed
by several groups for the partial or total synthesis of natural products possessing this
motif (Scheme 4.2) [2].
A major breakthrough was made during 1990-2000 when it was shown that
nucleophilic addition of water, alcohols, amines, and arenes to alkynes or alkenes
5
PPh
2
N
Fe
N
O
PPh
2
[Au(
c
-HexNC)
2
]BF
4
(1 mol%)
O
ste
p
s
OH
N
O
H
2
HO
n
-C
13
H
27
CH
2
Cl
2
, rt
MeO
2
C
NH
2
n
-C
13
H
27
n
-C
13
H
27
(ee = 93%)
80%
D-
threo
-Sphingosine [ref 2a]
N
N
PPh
2
Fe
PPh
2
[Au(
c
-HexNC)
2
]BF
4
(1 mol%)
N
O
ste
p
s
OH
O
HOOC
2
MeO
2
C
H
CH
2
Cl
2
, rt
MeHN
77%
(de = 85%)
MeBmt [ref 2b]
PPh
2
N
Fe
N
PPh
2
[Au(
c
-HexNC)
2
]BF
4
(1 mol%)
O
OH
N
O
HOOC
2
H
NH
2
MeO
2
C
CH
2
Cl
2
, rt
PhtN
MeHN
NPht
73%
(ee = 93%)
threo
-3-Hydroxylysine [ref 2c]
N
N
O
PPh
2
Fe
PPh
2
[Au(
c
-HexNC)
2
]BF
4
(1 mol%)
CN
CO
2
t
-Bu
N
O
ste
p
s
COOH
O
MeO
2
C
CH
2
Cl
2
, rt
80%
COOH
H
H
EtS
SEt
(-)- -Kainic acid [ref 2d]
SCHEME 4.2
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