Biomedical Engineering Reference
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OAc
OMe
OMe
OMe
OMe
NaH, Pd(OAc)
2
dppe, DMF
H
MeO
2
C
I
MeO
2
C
65%
MeO
MeO
MeO
2
C
MeO
2
C
O
O
349
350
O
O
OH
O
O
OH
H
2
N
HO
H
H
OH
Me
2
N
351
SCHEME 9.61
Synthesis of the tetracycline core structure by Tietze and coworkers.
(Scheme 9.63) [136,137].
is the most potent member of the vitamin
E family, which acts as an antioxidant to protect cells from oxidative stress. It is
important to note that only the stereoisomers containing (
R
)-configuration at the
stereogenic center of the chromane ring are active
in vivo
. The newly developed
domino reaction, which is one of the very few examples of truly enantioselective
domino reactions, allows the formation of the chromane ring system and parts of the
-Tocopherol
365
a
O
O
Ph
Ph
OBn
I
HO
Pd(PPh
3
)
4
CO, CO
2
Et
3
N
OBn
OBn
HO
HO
O
O
O
O
O
O
O
O
352
353
354
Ph
Pd
O
O
O
Ph
Ph
O
O
OBn
OBn
O
O
OBn
Pd
O
O
O
O
O
O
O
357
356
355
O
O
Ph
O
H
H
H
OBn
O
Pd
O
-Pd(0)
O
steps
O
O
Ph
OBn
O
H
Ph
O
O
Biyouyanagin A
360
O
358
359
SCHEME 9.62
Synthesis of biyouyanagin A
360
by Nicolaou and coworkers.
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