6831
Acknowledgements
We thank Professor Kazuhiko Saigo, the University of Tokyo, for helpful discussion and Ms.
Miou Kobayashi for her early contribution. Technical support from the Daicel Corporation for
the optical resolution of 12 is gratefully acknowledged.
References
1. For synthetic studies on this class of natural products, see: Kitamura, M.; Ohmori, K.; Kawase, T.; Suzuki, K.
Angew. Chem., Int. Ed. Engl. 1999, 38, 1229±1232, and references cited therein.
2. For isolation and structure elucidation, see: (a) Oki, T.; Konishi, M.; Tomatsu, K.; Tomita, K.; Saitoh, K.;
Tsunakawa, M.; Nishio, M.; Miyaki, T.; Kawaguchi, H. J. Antibiot. 1988, 41, 1701±1704; (b) Takeuchi, T.; Hara,
T.; Naganawa, H.; Okada, M.; Hamada, M.; Umezawa, H.; Gomi, S.; Sezaki, M.; Kondo, S. J. Antibiot. 1988, 41,
807±811.
3. Stevens, C. L.; Blumbergs, P.; Otterbach, D. H.; Strominger, J. L.; Matsuhashi, M.; Dietzler, D. N. J. Am. Chem.
Soc. 1964, 86, 2937±2938.
4. Richtmyer, N. K. Methods in Carbohydr. Chem. 1976, 2, 107±113.
5. Kanie, O.; Ito, Y.; Ogawa, T. J. Am. Chem. Soc. 1994, 116, 12073±12074.
6. Ferrier, R. J.; Furneaux, R. H. Carbohydr. Res. 1976, 52, 63±68.
7. (a) Veeneman, G. H.; van Leeuwen, S. H.; van Boom, J. H. Tetrahedron Lett. 1990, 31, 1331±1334; (b)
Konradsson, P.; Udodong, U. E.; Fraser-Reid, B. Tetrahedron Lett. 1990, 31, 4313±4316.
8. (a) Nicolaou, K. C.; Chucholowski, A.; Dolle, R. E.; Randall, J. L. J. Chem. Soc., Chem. Commun. 1984, 1155±
1156; (b) Hashimoto, S.; Hayashi, M.; Noyori, R. Tetrahedron Lett. 1984, 25, 1379±1382; (c) Mukaiyama, T.;
Murai, Y.; Shoda, S. Chem. Lett. 1981, 431±432.
9. (a) Suzuki, K.; Maeta, H.; Matsumoto, T.; Tsuchihashi, G. Tetrahedron Lett. 1988, 29, 3571±3574; (b) Suzuki, K.;
Maeta, H.; Matsumoto, T. Tetrahedron Lett. 1989, 30, 4853±4856.
10. In the presence of Cp2HfCl2±AgClO4, the b-xylosyl glycoside undergoes anomerization in the reactions at higher
temperature, typically 0ꢀC or above.
11. This result could be rationalized as follows: The b-phenyl glycoside, formed if any, would be more reactive,
thereby undergoing a neighboring group-assisted departure of the phenoxide, possibly in a reversible manner, and
the less reactive a-glycoside was accumulated.
12. (a) Matsumoto, T.; Katsuki, M.; Suzuki, K. Tetrahedron Lett. 1988, 29, 6935±6938; (b) Matsumoto, T.; Hosoya,
T.; Suzuki, K. Tetrahedron Lett. 1990, 31, 4629±4632.
13. Enantiomerically pure (S,S)-12eq14 was prepared by the SmI2-promoted pinacol coupling of the corresponding
dialdehyde (þ)-1516,17 followed by the enantiomer separation by using preparative chiral HPLC column
chromatography (Daicel Chiralcel OJ, 20 mmÂ250 mm, eluted with hexanes:i-PrOH=90:10, ¯ow rate 2.5 mL/
min). The CD spectrum showed that the latter fraction was the (S,S)-enantiomer from the literature data.15 The
corresponding diaxial conformer, (S,S)-12ax, was obtained via the following steps: (1) Ac2O/pyridine; (2) Á/
toluene; (3) K2CO3/MeOH. Partial protection of the hydroxy groups in 12 aorded the mono-protected
compounds 13 and 14.