D. O. Jang et al. / Tetrahedron Letters 42 (2001) 1073–1075
1075
we investigated, the trifluoroacetate of alcohol showed
the most promising results. When the reaction of trifl-
uoroacetate of cyclododecanol with diphenylsilane was
carried out at 140°C in the presence of di-tert-butyl
peroxide as the initiator in a sealed tube, cyclododecane
was obtained in 90% yield with a small amount of the
recovered starting material (entry 7). Finally, the reac-
tion could be optimized to give 98% yield of cyclodode-
cane (entry 8). Although a longer reaction time was
required, the reaction was proceeded at 130°C (entry 9).
M. Tetrahedron 1987, 43, 3541; (d) Hartig, W. Tetra-
hedron 1983, 39, 2609.
2. Barton, D. H. R.; McCombie, S. W. J. Chem. Soc.,
Perkin Trans. 1 1975, 1574.
3. (a) Oba, M.; Nishiyama, K. Synthesis 1994, 624; (b)
Nishiyama, K.; Oba, M.; Oshimi, M.; Sugawara, T.;
Ueno, R. Tetrahedron Lett. 1993, 23, 3745; (c) Barton, D.
H. R.; Jang, D. O.; Jaszberenyi, J. Cs. Tetrahedron 1993,
49, 7193; (d) Barton, D. H. R.; Jang, D. O.; Jaszberenyi,
J. Cs. Tetrahedron 1993, 49, 2793; (e) Barton, D. H. R.;
Jang, D. O.; Jaszberenyi, J. Cs. Tetrahedron Lett. 1992,
33, 6629; (f) Chatgilialoglu, C. Acc. Chem. Res. 1992, 25,
188; (g) Barton, D. H. R.; Jang, D. O.; Jaszberenyi, J. Cs.
Synlett 1991, 435; (h) Barton, D. H. R.; Jang, D. O.;
Jaszberenyi, J. Cs. Tetrahedron Lett. 1991, 32, 7187; (i)
Cole, S. J.; Kirwan, J. N.; Roberts, B. P.; Wills, C. R. J.
Chem. Soc., Perkin Trans. 1 1991, 103; (j) Kirwan, J. N.;
Roberts, B. P.; Willis, C. R. Tetrahedron Lett. 1990, 31,
5093; (k) Barton, D. H. R.; Jang, D. O.; Jaszberenyi, J.
Cs. Tetrahedron Lett. 1990, 31, 4681.
The reaction was applied to the deoxygenation of vari-
ous alcohols. The results are summarized in Table 2.
Secondary alcohols and even the primary alcohols were
efficiently transformed into the corresponding hydro-
carbons (entries 1–4). Tertiary alcohols afforded some-
what lower yields of the deoxygenated products (entry
5
). The process could be used for the deoxygenation of
steroids. Dihydrocholesteryl trifluoroacetate was con-
verted into the corresponding hydrocarbon in 87% yield
(
entry 6). Selective deoxygenation of sugars is a very
4. (a) Jang, D. O. Tetrahedron Lett. 1996, 37, 5367; (b)
Barton, D. H. R.; Jang, D. O.; Jaszberenyi, J. Cs. J. Org.
Chem. 1993, 58, 6838; (c) Barton, D. H. R.; Jang, D. O.;
Jaszberenyi, J. Cs. Tetrahedron Lett. 1992, 33, 5709.
5. Barton, D. H. R.; Jang, D. O.; Jaszberenyi, J. Cs. Tetra-
hedron Lett. 1992, 33, 2311.
6. (a) Jang, D. O.; Cho, D. Y.; Barton, D. H. R. Synlett
1998, 39; (b) Jang, D. O.; Cho, D. Y.; Kim, J. Synth.
Commun. 1998, 28, 3559.
7. Barton, D. H. R.; Jacob, M. Tetrahedron Lett. 1998, 39,
1331.
8. Robins, M. J.; Wilson, J. S.; Hansske, F. J. Am. Chem.
Soc. 1983, 105, 4059.
important tool for the modification of sugars that are
widely used as antibiotics and chiral building blocks in
organic synthesis. The trifluoroacetates could be uti-
lized for the preparation of deoxysugars. Trifluoroac-
etates of secondary alcohol of 1,2:5,6-di-O-isopropyli-
dene-a-
di-O-isopropylidene-a-
deoxygenated product in 83 and 82% yield, respectively,
under the conditions (entries 7 and 8). In summary,
trifluoroacetate derivatives of alcohols can be used as
precursors for the radical deoxygenation of various
alcohols. They can be prepared without using toxic,
expensive derivatizing reagents.
1
1
D
-glucofuranose and primary alcohol of 1,2:3,4-
-galactopyranose produced the
D
9. Carney, R. E.; McAlpine, J. B.; Jackson, M.; Stanaszek,
R. S.; Washburn, M.; Cirovic, M.; Mueller, S. L. J.
Antibiot. 1978, 31, 441.
Acknowledgements
10. (a) Sano, H.; Taketa, T.; Migita, T. Synthesis 1988, 402;
(
b) Saito, I.; Ikehira, H.; Kasatani, R.; Watanabe, M.;
Matsuura, T. J. Am. Chem. Soc. 1986, 108, 3115; (c)
Boar, R. B.; Joukhadar, L.; McGhie, J. F.; Misra, S. C.;
Barrett, A. G. M.; Barton, D. H. R.; Prokopiou, P. A. J.
Chem. Soc., Chem. Commun. 1978, 68; (d) Dashayes, H.;
Pete, J. P.; Portella, C. Tetrahedron Lett. 1976, 2019; (e)
Baldwin, S. W.; Haut, S. A. J. Org. Chem. 1975, 40, 3885;
This work was supported by Korea Research Founda-
tion Grant (1999-015-DP0219).
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