J. S. Yadav et al. / Tetrahedron Letters 45 (2004) 4583–4585
4585
OH
O
O
O
IBX
O
10 mol% InCl3
H2O
RO
RO
RO
RO
RO
RO
OR
Scheme 3.
5. (a) Takhi, M.; Adel-Rahman, A. A. H.; Schimdt, R. R.
Synlett 2001, 427–429; (b) Takhi, M.; Adel-Rahman, A.
A. H.; Schimdt, R. R. Tetrahedron Lett. 2001, 42, 4053–
4056; (c) Yadav, J. S.; Reddy, B. V. S.; Raju, A. K.; Rao,
C. V. Tetrahedron Lett. 2002, 43, 5437–5440.
6. (a) Mieczkowski, J.; Jurczak, J.; Chmielewski, M.; Zamoj-
ski, A. Carbohydr. Res. 1977, 56, 180–182; (b) Jarglis, P.;
Lichtenthaler, F. W. Tetrahedron Lett. 1982, 23, 3781–
3784.
7. Panfil, I.; Mostowicz, D.; Chmielewski, M. Polish J.
Chem. 1999, 73, 1099–1110.
8. Rollin, P.; Sinay, P. Carbohydr. Res. 1981, 98, 139–142.
9. (a) Varvoglis, A. Hypervalent Iodine in Organic Synthesis;
Academic: San Diego, 1997; (b) Wirth, T.; Hirt, U. H.
Synthesis 1999, 1271–1287.
10. (a) Hartman, C.; Meyer, V. Chem. Ber. 1893, 26, 1727; (b)
Stang, P. J.; Zhdankin, V. V. Chem. Rev. 1996, 96, 1123–
1178; (c) Kitamura, T.; Fujiwara, Y. Org. Prep. Proc. Int.
1997, 29, 409–458.
11. Wirth, T. Angew. Chem. Int. Ed. 2001, 40, 2812–2814.
12. (a) Nicolaou, K. C.; Montagnon, T.; Baran, P. S. Angew.
Chem. Int. Ed. 2002, 41, 993–996; (b) Nicolaou, K. C.;
Barn, P. S.; Zhong, Y.-L.; Barluenga, S.; Hunt, K. W.;
Kranich, R.; Vega, J. A. J. Am. Chem. Soc. 2002, 124,
2233–2244.
In all cases, the reactions were carried out in a water/
acetonitrile (1:9) solvent system. Since indium trichlo-
ride is stable in water, no precautions needed to be taken
to exclude moisture from the reaction medium. Fur-
thermore, this method does not require stringent reac-
tion conditions. The experimental procedure is quite
simple and convenient affording the desired products in
good yields. Among various catalysts such as scandium
triflate, ytterbium triflate, cerium triflate and indium
triflate employed for this transformation, indium tri-
chloride was found to be the most effective catalyst in
terms of conversion and reaction rates. Low conversions
(40–55%) were obtained when the reactions were carried
out using 5 mol % Sc(OTf)3 and 2.5 equiv of IBX in
refluxing acetonitrile–water (9:1). Furthermore, the
combination of IBX with conventional Lewis acids such
as BF3ꢀOEt2, TiCl4 and TMSOTf failed to give the
desired enelactones. The scope and generality of this
process is illustrated with respect to various glycals and
the results are presented in Table 1.14
In summary, we describe a novel procedure for the
preparation of 2,3-dideoxy-D-hex-2-enono-1,5-lactones
13. (a) Li, C. J.; Chan, T. H. Tetrahedron 1999, 55, 11149–
11176; (b) Babu, G.; Perumal, P. T. Aldrichim. Acta 2000,
33, 16–22; (c) Ghosh, R. Indian J. Chem. 2001, 40B, 550–557.
from glycals using InCl3/IBX. This method is not only
applicable to simple acetyl glycals but also to highly
functionalized benzyl, benzoyl and allyl glycals. This
new reagent system provides a simple and convenient
method for the preparation of optically active a,b-
unsaturated d-lactones.
14. General procedure: A mixture of 3,4,6-tri-O-acetyl-D-
glucal (1 mmol) and InCl3 (10 mol %) and IBX (2.5 mmol)
in acetonitrile–water (10 mL, 9:1) was stirred at 80 ꢁC for
the appropriate time. After complete conversion, as
indicated by TLC, the reaction mixture was filtered and
washed with ethyl acetate (2 · 10 mL). The combined
organic layers were washed with brine and dried over
anhydrous Na2SO4 and purified by column chromatogra-
phy on silica gel (Merck, 100–200 mesh, ethyl acetate–
hexane, 1:9) to afford pure enelactone. 4,6-Di-O-ace-
Acknowledgements
B.V.S. and Ch.S.R. thank CSIR, New Delhi for the
award of fellowships.
tyl-2,3-dideoxy-a-D-erythro-hex-2-enono-1,5-lactone 2a:
27
liquid, ½aꢁ þ 127:5 (c 1.0, CHCl3); 1H NMR (CDCl3,
D
200 MHz):
d 2.08 (s, 3H, –COCH3), 2.10 (s, 3H,
–COCH3), 4.25 and 4.30 (each dd, 1H, J ¼ 4:0, 11.5 Hz,
H-6,60), 4.65 (dt, 1H, J ¼ 7:5, 4.0 Hz, H-5), 5.50 (dt, 1H,
J ¼ 2:9, 7.5 Hz, H-4), 6.10 (dd, 1H, J ¼ 1:7, 10.0 Hz, H-2),
6.75 (dd, 1H, J ¼ 2:9, 10.0 Hz, H-3). 13C NMR (CDCl3,
50 MHz): d 20.4, 20.5, 61.8, 63.3, 77.2, 122.2, 142.9, 160.1,
169.5, 170.1. IR (KBr): m 3077, 2957, 1745, 1640, 1372,
1220, 1113, 1049, 976, 819, 771 cmꢂ1. FAB Mass: m=z: 228
References and notes
1. (a) Hanessian, S. Total Synthesis of Natural Products: The
Chiron Approach; Pergamon: Oxford, 1984; (b) Hanessian,
S.; Lou, B. Chem. Rev. 2000, 100, 4443–4463.
2. (a) Postema, M. H. D. Tetrahedron 1992, 48, 8545–8599;
(b) Danishefsky, S. J.; Bilodeau, M. T. Angew Chem., Int.
Ed. 1996, 35, 1380–1419.
3. (a) Danishefsky, S. J.; Allen, J. R. Angew Chem., Int. Ed.
2000, 39, 836–863; (b) Nicolaou, K. C.; Mitchel, H. J.
Angew. Chem., Int. Ed. 2001, 40, 1576–1624.
4. (a) Ferrier, R. J.; Prasad, N. J. J. Chem. Soc. C 1969, 570–
572; (b) Ferrier, R. J. Adv. Carbohydr. Chem Biochem.
1969, 24, 199–266; (c) Fraser-Reid, B. Acc. Chem. Res.
1985, 18, 347–354; (d) Wieczorek, E. Acros Organics Acta
2003, 10, 13–14.
(Mþ), 155, 126, 97, 84, 68. 4,6-di-O-benzyl-2,3-dideoxy-a-
27
D
D
-erythro-hex-2-enono-1,5-lactone 2d: liquid, ½aꢁ þ 54:8
1
(c 1.4, CHCl3); H NMR (CDCl3, 200 MHz): d 3.70 and
3.73 (each dd, 1H, J ¼ 3:9, 11.6 Hz, H-6,60), 4.35–4.65 (m,
6H, H-4, H-5, –H2 C–Ph), 5.95 (dd, 1H, J ¼ 1:8, 10.0 Hz,
H-2), 6.80 (dd, 1H, J ¼ 3:0, 10.0 Hz, H-3), 7.20–7.35 (m,
10H). 13C NMR (CDCl3, 50 MHz) d: 67.8, 68.6, 72.2, 73.5,
79.9, 96.0, 120.5, 127.7, 128.4, 128.8, 136.9, 137.5, 146.2,
162.4. IR (KBr): m 3028, 2917, 2867, 1719, 1634, 1455,
1372, 1229, 1099, 1039, 972, 819, 744 cmꢂ1. FAB Mass:
m=z: 324 (Mþ), 155, 126, 97, 84, 68.