3056
H. Tanaka et al. / Tetrahedron Letters 44 (2003) 3053–3057
ple deprotection reactions and glycosylation of resulting
hydroxyl groups are attractive protocols to achieve
utilizing an automated synthesizer. The phytoalexin
elicitor activity of these oligosaccharides is currently
being explored along with the application of the one-
pot deprotection method to other oligosaccharide
libraries.
C.-H. Chem. Eur. J. 1999, 5, 3326–3340; (d) Adinolfi, M.;
Barone, G.; Guariniello, L.; Iadonisi, A. Tetrahedron
Lett. 2000, 41, 9305–9309.
8. The use of Fmoc as a hydroxyl protecting group in
oligosaccharide synthesis has been reported in a few
examples. See: (a) Freese, S. J.; Vann, W. F. Carbohydr.
Res. 1996, 281, 313–319; (b) Nicolaou, K. C.; Winssinger,
N.; Pastor, J.; DeRoose, F. J. Am. Chem. Soc. 1997, 119,
449–450; (c) Nicolaou, K. C.; Watanabe, N.; Li, J.;
Pastor, J.; Winssinger, N. Angew. Chem., Int. Ed. 1998,
37, 1559–1561; (d) Roussel, F.; Knerr, L.; Grathwohl,
M.; Schmidt, R. R. Org. Lett. 2000, 2, 3043–3046; (e)
Zhu, T.; Boons, G.-J. J. Am. Chem. Soc. 2000, 122,
10222–10223; (f) Wu, X.; Grathwohl, M.; Schmidt, R. R.
Org. Lett. 2001, 3, 747–750.
Acknowledgements
This work was supported by the Ministry of Education,
Science, Sports, and Culture, Japan.
9. Green, T. W.; Wuts, P. G. M. Protective Groups in
Organic Synthesis; 3rd ed.; John Wiley & Sons: New
York, 1999; p. 168.
References
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1
10. Spectral data of 5: H NMR (270 MHz, CDCl3): l −0.41
(s, 3H), −0.14 (s, 3H), 0.72 (s, 9H), 2.00 (s, 3H), 2.18 (t,
2H, J=6.6 Hz), 2.39 (t, 2H, J=6.6 Hz), 3.29–3.71 (m,
13H), 3.88 (dd, 1H, J=6.9, 6.9 Hz), 4.04–4.59 (m, 20H),
4.72–4.93 (m, 6H), 5.02 (dd, 1H, J=7.9, 8.3 Hz), 5.19
(dd, 1H, J=10.6, 10.6 Hz), 5.24 (br-d, 1H, J=10.2 Hz),
5.34 (br-d, 1H, J=17.5 Hz), 5.51 (s, 1H), 5.92 (ddt, 1H,
J=10.2, 17.5, 5.9 Hz), 7.04–7.61 (m, 45H, Ar), 7.72 (d,
2H, J=8.6 Hz), 7.77 (d, 2H, J=9.2 Hz), 7.93 (d, 2H,
J=7.3 Hz), 7.98 (d, 2H, J=7.3 Hz); 13C NMR (67.8
MHz, CDCl3): l −4.6, −4.1, 17.7, 25.6, 27.6, 29.7, 37.7,
46.7, 66.3, 66.5, 68.5, 70.1, 70.2, 71.7, 72.8, 73.1, 73.2,
73.7, 74.0, 74.2, 74.6, 74.8, 75.0, 75.4, 77.2, 77.3, 78.7,
78.9, 79.0, 79.3, 97.7, 98.3, 99.4, 99.9, 102.0, 119.0, 120.0,
125.2×2, 126.6, 127.7×2, 127.8, 127.9, 128.0, 128.1,
128.3×2, 128.4, 128.5, 128.8, 128.9, 129.2, 129.3, 129.6×2,
129.7, 129.9, 130.2, 131.6, 133.2, 133.7, 136.7, 137.3,
137.5, 137.9, 138.2, 141.3, 143.3, 143.4, 154.8, 154.9,
164.3, 164.5, 164.7, 165.5, 172.3; IR (KBr) 2998, 2996,
2892, 2800, 1720, 1255, 1985, 769 cm−1. Anal. calcd for
C117H120O31Si: C, 68.54; H, 5.90. Found: C, 65.55; H,
6.01%.
,
Sharp, J. K.; Albersheim, P.; Ossowski, P.; Pilotti, A.;
Garegg, P.; Lindberg, B. J. Biol. Chem. 1984, 259, 11341–
11345.
3. (a) Yamaguchi, T.; Yamada, A.; Hong, N.; Ogawa, T.;
Ishii, T.; Shibuya, N. Plant Cell 2000, 12, 817–826; (b)
Yamaguchi, T.; Maehara, Y.; Kodama, O.; Okada, M.;
Matsumura, M.; Shibuya, N. J. Plant Physiol. 2002, 159,
1147–1149.
4. For synthetic studies of phytoalexin elicitors in soybeans,
see: (a) Yamada, H.; Harada, T.; Takahashi, T. J. Am.
Chem. Soc. 1994, 116, 7919–7920; (b) Yamada, H.; Taki-
moto, H.; Ikeda, T.; Tsukamoto, H.; Harada, T.; Taka-
hashi, T. Synlett 2001, 1751–1754; (c) Tanaka, H.;
Adachi, M.; Tsukamoto, H.; Ikeda, T.; Yamada, H.;
Takahashi, T. Org. Lett. 2002, 4, 4213–4216.
5. For synthetic studies of phytoalexin elicitors in rice, see:
(a) Amaya, T.; Tanaka, H.; Yamaguchi, T.; Shibuya, N.;
Takahashi, T. Tetrahedron Lett. 2001, 42, 9191–9194; (b)
Takahashi, T.; Okano, A.; Amaya, T.; Tanaka, H.; Doi,
T. Synlett 2002, 911–914.
6. For orthogonal deprotection strategy on a mono-saccha-
ride scaffold, see: (a) Wunberg, T.; Kallus, C.; Opatz, T.;
Henke, S.; Schmidt, W.; Kunz, H. Angew. Chem., Int. Ed.
1998, 37, 2503–2505; (b) Wong, C.-H.; Ye, X.-S.; Zhang,
Z. J. Am. Chem. Soc. 1998, 120, 7137–7138; (c) Kallus,
C.; Opatz, T.; Wunberg, T.; Schmidt, W.; Henke, S.;
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T.; Boons, G.-J. Tetrahedron: Asymmetry 2000, 11, 199–
205.
11. Kunz, H.; Unverzagt, C. Angew. Chem., Int. Ed. Engl.
1984, 23, 436–437.
12. Experimental procedure for the sequential selective
deprotection of 5 utilizing an automated synthesizer (L-
COS™): Seven reaction vessels 1–7 were placed on the
L-COS™. A solution of 5 (35 mg, 0.017 mmol) in THF
(0.5 mL) was added to each of the reaction vessels 1–7 at
room temperature. For removal of the Alloc groups, two
solutions of dimedone (5 mg, 36.0 mmol) in THF (0.2
mL) and Pd(PPh3)4 (5 mg, 4.3 mmol) in THF (0.2 mL)
were added to each of the reaction vessels 1–4 at room
temperature. The reaction mixtures were stirred at the
same temperature for 15 min. For removal of the Fmoc
group, a solution of piperidine (20 mL, 0.20 mmol) in
THF (0.2 mL) was added to each of the reaction vessels
2, 3, 5, and 6 at room temperature. The reaction mixtures
were stirred at the same temperature for 15 min. For
removal of the Lev group, a solution of hydrazine (29 mL,
0.93 mmol)–acetic acid (73 mL, 1.28 mmol) in THF (0.2
mL) was added to each of the reaction vessels 3, 4, 6, and
7 at the same temperature. After stirring at the same
temperature for 30 min, the reaction mixtures were auto-
7. The use of Alloc as a hydroxyl protecting group in
oligosaccharide synthesis has been reported in a few
examples. See: (a) Teshima, T.; Nakajima, K.; Takahashi,
M.; Shiba, T. Tetrahedron Lett. 1992, 33, 363–366; (b)
Harada, T.; Yamada, H.; Tsukamoto, H.; Takahashi, T.
J. Carbohydr. Chem. 1995, 14, 165–170; (c) Depre´, D.;
Du¨ffels, A.; Green, L. G.; Lenz, R.; Ley, S. V.; Wong,