M. Labora et al. / Tetrahedron: Asymmetry 22 (2011) 1705–1707
1707
CH3
CH3
CH3
OH
OH
O
O
O
O
AcOH aq. (50%),
50ºC, 51%
AcOAg, I2, AcOH
74%
AcO
AcO
5
I
I
12
11
CH3
OH
CH3
CH3
O
O
NaOH, CH2Cl2 (dry)
66%
K2CO3
MeOH, 78%
IBX
DMF, 90%
AcO
AcO
HO
O
O
O
14
13
(-)-epoformin 1b
CH3
O
CH3
O
K2CO3, MeOH
97%
DEAD, PPh3,
O
O
p-NBA, benzene
HO
(-)-epiepoformin 2b
60%
O
O
NO2
15
Scheme 3. Synthesis of (À)-epoformin and (À)-epiepoformin from 5.
8. Tachihara, T.; Kitahara, T. Tetrahedron 2003, 59, 1773–1780.
3. Conclusion
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Tetrahedron 2003, 59, 10159–10164.
We have demonstrated the applicability of cis-cyclohexadien-
ediols of microbial origin to complete the synthesis of the natural
product (À)-gabosine A and two unnatural epoxyenones (À)-
epoformin 1b and epiepoformin 2b from these starting materials.
Further applications of this strategy for the preparation of related
natural molecules are currently under investigation in our labora-
tory and will be reported in due course.
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Acknowledgments
The authors are grateful to PEDECIBA (PNUD/URU/06/004) for
the financial support of this work. Maitia Labora thanks PEDECIBA
and ANII for a doctoral fellowship.
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