J. S. Yada6, A. Maiti / Tetrahedron Letters 42 (2001) 3909–3912
3911
undergoes dehydrohalogenation and then further
deprotonation, resulting in the chiral diacetylenic
alcohol F after work-up. Our attempts to isolate
intermediate C failed because of its ability to iso-
merise.13
5. Yadav, J. S.; Deshpande, P. K.; Sharma, G. V. M.
Tetrahedron Lett. 1990, 31, 4495.
6. (a) Brandsma, L. Preparative Acetylenic Chemistry;
Elsevier: New York, 1971; (b) Shostakovskii, M. F.;
Bogdanova, A. V. The Chemistry of Diacetylenes; John
Wiley and Sons: New York, 1971.
Taking advantage of readily available sugars, a number
of desired 4,5-O-isopropylidene propargyl chlorides
were prepared in order to generalise and show the
versatility of the reaction (Table 1). When these chlo-
rides were treated with bases they underwent a clean
transformation to give exclusively diacetylenic alcohols.
All new compounds were characterised14 and found to
be enantiomerically pure.15
7. (a) Dabrowski, Z.; Wrobel, J. T.; Wojtasiewick, K. Phy-
tochemistry 1980, 19, 2464; (b) Hansen, L.; Boll, P. M.
Phytochemistry 1986, 25, 285.
8. (a) Kim, Y. S.; Jin, S. H.; Kim, S. I.; Halin, D. R. Arch.
Pharm. Res. 1989, 12, 207; (b) Matsunaga, H.; Katano,
M.; Yamamoto, H.; Fujito, H.; Mori, M.; Tukata, K.
Chem. Pharm. Bull. 1990, 38, 3480; (c) Saita, T.; Mat-
sunaga, H.; Yamamoto, H.; Nagumo, F.; Fujito, H.;
Mori, M. Biol. Pharm. Bull. 1994, 17, 798.
In conclusion, it is worth mentioning that the elimina-
tion reaction is highly chemoselective, since the other
functionality present in the substrate remains unaf-
fected and that the transformation can be carried out
under mild conditions and in high yield. These are very
useful synthons that will hopefully find widespread
application in the synthesis of biologically active
compounds.
9. (a) Zheng, G.; Lu, W.; Aisa, H. A.; Cai, J. Tetrahedron
Lett. 1999, 40, 2181; (b) Lu, W.; Zheng, G.; Aisa, A.; Cai,
J. Tetrahedron Lett. 1998, 39, 9521; (c) Lu, W.; Zheng,
G.; Gao, D.; Cai, J. Tetrahedron 1999, 55, 7157; (d)
Gurjar, M. K.; Kumar, V. S.; Rao, B. V. Tetrahedron
1999, 55, 12563; (e) Lu, W.; Zheng, G.; Cai, J. Synlett
1998, 737.
10. Watanabe, K.; Tsndo, Y.; Yamane, Y.; Takahashi, H.;
Iguchi, K.; Naoki, H.; Fujita, T.; VonSoest, R. W. M.
Tetrahedron Lett. 2000, 41, 9271.
11. Hanessian, S. Total Synthesis of Natural Products: The
Acknowledgements
‘Chiron Approach’; Pergamon: Oxford, 1983.
For example, substrate 6a was prepared from
D-ara-
binose in six steps in 65% overall yield as described
below:
A.M. would like to thank the CSIR, New Delhi, India,
for financial assistance.
References
12. Eglinton, G.; Jones, E. R. H.; Whiting, M. C. J. Chem.
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Yadagiri, P.; Yadav, J. S. Tetrahedron Lett. 1985, 26,
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Carbohydrate Res. 1987, 165, 116; (c) Rama Rao, A. V.;
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13. Rutledge, T. F. Acetylenes and Allenes; Reinhold: New
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14. Typical experimental procedure: Method A: To a stirred
suspension of lithium amide (prepared from 0.039 g, 5.5
mg of Li) in liquid ammonia (20 mL), propargyl chloride
6a (0.5 g, 1.74 mmol) in THF:HMPA (5:1, 3 mL) was
added and stirred for 30 min. The reaction was quenched
with solid ammonium chloride (2 g) and excess ammonia
was evaporated. The residue was dissolved in water and
extracted with ether. The organic layer was washed, dried
(Na2SO4) and evaporated under reduced pressure. The
crude product was purified by flash column chromatogra-
phy (eluent: 15% ethyl acetate in hexane) to afford
diacetylenic alcohol 6b (0.26 g, 83%) as a colourless oil.
Method B: To a stirred solution of propargyl chloride 6a
(0.5 g, 1.74 mmol) in THF:HMPA (5:1, 15 mL) at −78°C
3. Yadav, J. S.; Barma, D. K.; Dutta, D. Tetrahedron Lett.
1997, 38, 4470.
4. (a) Yadav, J. S.; Deshpande, P. K.; Sharma, G. V. M.
Tetrahedron 1990, 46, 7033; (b) Yadav, J. S.; Prahlad, V.;
Chander, M. C. J. Chem. Soc., Chem. Commun. 1993,
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