temperature. After stirring the reaction mixture at room tem-
perature for further 2 h and workup, involving dilution with
ether, washing with a saturated NaHCO3 solution and with
brine, drying over MgSO4, removal of the solvent, and chrom-
atographic purification (n-hexane–ethyl acetate, 6:1) of the
resulting residue first gave (1S,2R)-oxyselenide 1 (2.14 g, 39%)
(Found: C, 66.23; H, 5.83. C25H26O3Se requires C, 66.20; H,
5.78%); mp 98–99 ЊC; Rf 0.43 (silica gel, hexane–EtOAc = 3:1);
[α]D Ϫ48.3 (c 4.35 in CHCl3); νmax (NaCl)/cmϪ1 3557; δH (500
MHz; CDCl3; Me4Si) 1.47–1.61 (3 H, m), 2.18–2.21 (1 H, m),
3.21–3.25 (1 H, m), 3.29–3.33 (1 H, m), 3.60–3.62 (1 H, m), 3.90
(1 H, s), 4.54 and 4.68 (2 H, ABq, J 7.9), 4.80 (1 H, d, J 6.5),
6.96–7.27 (13 H, m) and 7.63–7.64 (2 H, m); δC (125.8 MHz;
CDCl3; Me4Si) 25.1, 28.7, 44.5, 44.8, 45.0, 64.4, 79.1, 87.3,
105.2, 127.1, 127.3, 127.4, 127.5, 127.7, 128.6, 129.1, 134.4,
138.9 and 139.2. Continued elution gave a diastereomer of 1,
(1R,2S)-oxyselenide (1.76 g, 32%) (Found: C, 66.22; H, 5.79.
C25H26O3Se requires C, 66.20; H, 5.78%); Rf 0.33 (silica gel,
hexane–EtOAc = 3:1); [α]D ϩ3.47 (c 2.1 in CHCl3); δH (500
MHz; CDCl3; Me4Si) 1.57–1.70 (4 H, m), 2.18 (1 H, m), 3.35
(1 H, m), 3.44–3.47 (2 H, m), 3.91–3.93 (1 H, m), 4.46 (1 H, d,
J 6.0 ), 4.67 and 4.70 (2 H, ABq, J 8.2), 7.02–7.26 (13 H, m) and
7.42–7.44 (2 H, m); δC (125.8 MHz; CDCl3; Me4Si) 24.9, 28.1,
43.7, 63.9, 78.1, 84.0, 99.8, 127.3, 127.5, 127.6, 127.8, 128.0,
128.2, 128.9, 134.3, 136.9 and 139.5.
6-O-(ꢀ-D-Arabinopyranosyl)-1,2:3,4-di-O-isopropylidene-ꢁ-D-
galactopyranose (13)
To a solution of 12 (193 mg, 0.54 mmol) in acetone (10 cm3)
and water (2 cm3), NMO (69 mg, 0.59 mmol) and osmium tetr-
oxide (12.7 mg, 0.05 mmol) were added at room temperature
and the reaction mixture was stirred at 50 ЊC for 24 h. After
stirring the reaction mixture with NaHSO4 (32 mg), it was
partitioned between methylene chloride and water. The organic
phase was dried and evaporated to dryness and the residue was
chromatographed (chloroform–methanol, 8:1) to afford 13 (95
mg, 45%) and its diastereomers (81 mg, 38%). Compound 13
(Found: C, 52.05; H, 7.18. C17H28O10 requires C, 52.03; H,
7.19%); mp 78–80 ЊC; Rf 0.50 (silica gel, CHCl3–MeOH = 8:1);
[α]D Ϫ49.9 (c 0.75, CHCl3); νmax (CHCl3)/cmϪ1 3444; δH (250
MHz; CDCl3; Me4Si) 1.33 (3 H, s), 1.35 (3 H, s), 1.46 (1 H, s),
1.53 (1 H, s), 2.30 (3 H, br s), 3.55–3.80 (4 H, m), 3.91–4.04
(3 H, m), 4.29–4.35 (3 H, m), 4.61 (1 H, d, J 7.8) and 5.54 (1 H,
d, J 5.0).
Scheme 2 Reagents and conditions: i, dihydropyran, PhSeCl, Et3N,
THF, rt, 2 h, 76% of a mixture of 9 and its diastereomer; ii, NaIO4,
NaHCO3, MeOH–H2O, 60 ЊC, 2 h then CCl4, 60 ЊC, 2 h, 99% of a
mixture of 10 and its diastereomer; iii, MCPBA, CH2Cl2, rt, 48 h, 68%
of a mixture of 11 and its diastereomer; iv, PhSeSePh, NaBH4, EtOH,
reflux, 2 h; v, NaIO4, NaHCO3, MeOH–H2O, 60 ЊC, 1 h then CCl4,
reflux, 2 h, 65% of a mixture of 12 and its diastereomer in two steps;
vi, OsO4, NMO, acetone–H2O, 50 ЊC, 24 h, 45% of 13 and 38% of its
diastereomers.
ation of not only 9 and its diastereomer but also two diastereo-
mers in each step of the present reaction sequence shown in
Scheme 2 could not be achieved until the final stage. The ratio
of compound 9 and its diastereomer was, therefore, determined
from the 1H NMR spectrum of the diastereomeric mixture and
confirmed by the ratio of the separable final products, 13 and its
diastereomers. Oxidation–elimination of 9 and its diastereomer
and the subsequent completely stereoselective epoxidation of
the olefin 10 and its diastereomer afforded trans-epoxides, 11
and its diastereomer again in the ratio of 1.2:1. Dihydroxyl-
ation of allylic alcohols, 12 and its diastereomer, obtained from
11 and its stereoisomer, afforded a separable mixture of 6-O-(β-
-arabinopyranosyl)-1,2:3,4-di-O-isopropylidene-α--galacto-
pyranose (13) and its diastereomers13 in the ratio of 1.2:1
in 83% yield. The structure of compound 13 was determined
by the comparison of its physical and spectroscopic data
with those of the authentic 13, which was prepared from
-arabinose.14
Acknowledgements
This research was supported by a grant from Ministry of
Education of Korea (BSRI-98-3422). Support from the Center
for Molecular Design and Synthesis (CMDS) at KAIST is also
acknowledged. CWM is a research associate of the Basic
Science Institute of Yonsei University.
Notes and references
1 (a) J. F. Kennedy and C. A. White, Bioactive Carbohydrates in
Chemistry, Biochemistry and Biology, Halsted Press, New York,
1983; (b) P. M. Collins and R. J. Ferrier, Monosaccharides: Their
Chemistry and Their Roles in Natural Products, John Wiley, New
York, 1995.
2 (a) S. Y. Ko, A. W. M. Lee, S. Masamune, L. A. Reed, III, K. B.
Sharpless and F. J. Walker, Science, 1983, 220, 949; (b) H. Ogura,
A. Hasegawa and T. Suami, Carbohydrates: Synthetic Methods
and Applications in Medicinal Chemistry, Kodansha, Tokyo, 1992;
(c) K. Toshima and K. Tatsuda, Chem. Rev., 1993, 93, 1503.
3 K. S. Kim, J. I. Park, H. K. Moon and H. Yi, Chem. Commun., 1998,
1945.
4 (a) F. Sweet and R. K. Brown, Can. J. Chem., 1968, 46, 2289;
(b) A. Banaszek and A. Zamojski, Carbohydr. Res., 1975, 51, 276;
(c) M. Chinielewski, A. Konowal and A. Zamojski, Carbohydr. Res.,
1979, 70, 275; (d) K. B. Sharpless and R. F. Lauer, J. Am. Chem.
Soc., 1973, 95, 2697; (e) A. Zamojski, A. Banaszek and G. Gryn-
kiewcz, Adv. Carbohydr. Chem. Biochem., 1982, 40, 30; (e) A. P.
Kozikowski, R. J. Schmlesing and K. I. Sorgi, J. Am. Chem. Soc.,
Consequently, this result exhibited that the present method-
ology could be applied for the synthesis of a variety of mono-
and disaccharides by employing an appropriate chiral alcohol.
Currently underway is asymmetric oxyselenenylation by using
either a chiral selenium reagent or a chiral alcohol.
Experimental
(1R,2S)-Oxyselenide 1 and its diastereomer
To a solution of PhSeCl (2.31 g, 12.1 mmol) and 3,4-dihydro-
2H-pyran (1.02 g, 12.1 mmol) in THF (50 cm3) was added
slowly a solution of (S,S)-hydrobenzoin (2.59 g, 12.1 mmol)
and triethylamine (1.84 g, 18.2 mmol) in THF (7 cm3) at room
1342
J. Chem. Soc., Perkin Trans. 1, 2000, 1341–1343