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tandem oxidative
cyclizaiton with Re (VII)
Wittig coupling
OH
O
( )
n
4
O
O
1
HO
O
rollidecin C
n = 1
rollidecin D
n = 2
Sharpless AE
O
OH
M
OMO
PPh
3
I
C
12
H
25
C
12
H
25
115
116
OBPS
1. aldehyde
2. TMSBr, -30
117
118
n = 1
n = 2
O
O
°
( )
n
O
HO
Re
2
O
7
, TFAA
( )
n
C
12
H
25
119
n = 1
120
n = 2
BPS
O
O
O
BPS
O
O
C
12
H
25
rollidecin C
rollidecin D
( )
n
O
O
HO
O
121
n = 1
122
n = 2
Scheme 10-22. Total synthesis of rollidecin C and D by Keinan et al.
into the aldehyde 125, which was further subjected to the Wittig reaction with 70.
Final treatments of hydrogenation and deprotections, 126, were obtained and char-
acterized as natural asimilobin.
Grignard reactions were applied twice in Emde and Koert's synthesis of squamocin
A and D,
62,63
to link the segments 127, 128, and 131 together and establish the
OH
C
14
H
29
Co(modp)
2
CHO
( )
2
O
O
O
O
( )
2
O
2
MOMO
HO
OH
TBHP
OH
123
124
125
MOMO
MOMO
BrPh
3
P
1.
O
OH
70
C
14
H
29
O
O
O
O
HO
O
126
proposed structure for
asimilobin
Scheme 10-23. Total synthesis of asimilobin by Wang et al.
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