Chemistry Reference
In-Depth Information
THPO
THPO
Co
2
(CO)
8
(1.2 eq.)/
benzene, R.T.
Co(CO)
3
Co(CO)
3
H
H
OBn
H
HO
N
OBn
N
OBn
CO
2
Me
CO
2
Me
16
17
18
Yield 76 %
Yield 82 %
NMO (6 eq.)/
CH
2
Cl
2
,0°C
O
O
O
HO
HO
H
THPO
H
i) LiAlH
4
, CuI/
HMPA-THF (1:4), -78 °C
H
H
H
H
+
H
OBn
H
OBn
H
OBn
ii) Toluene-p-sulfonic acid/
MeOH, R.T.
N
N
N
CO
2
Me
CO
2
Me
CO
2
Me
19a
18a:18b
= 6:1
19b
O
HO
H
H
H
CO
2
H
CO
2
H
H
H
H
H
OBn
H
N
CO
2
Me
(-)-kainic acid
20
19a
Scheme 4.5
Synthesis of (-)-kainic acid
20
utilizing the Pauson-Khand reaction.
O
O
(i) Co
2
(CO)
8
/CH
2
Cl
2
+
H
H
OMOM
(ii) NMO (95%)
OMOM
N
Ts
OMOM
H
N
N
H
H
Ts
(1.7:1)
Ts
22
23
21
H
2
,Pd/C
OTMS
O
H
H
Me
Me
CO
2
H
CO
2
H
H
H
H
H
H
OMOM
OMOM
H
N
N
Ts
H
Ts
H
24
:(
-Me)
25
:(
α
-H,
β
-Me)
β
-H,
α
(-)-kainic acid
26
Scheme 4.6
The enantiospecific synthesis of (-)-kainic acid and its derivatives developed by
Yoo.
