ORDER
REPRINTS
260
NARAMA AND FUNABASHI
etate (10:1) or (5:1). Compounds were detected with iodine vapor or 5 % methano-
lic sulfuric acid spray followed by heating on a hot plate. Column chromatography
was performed by the flash technique on silica gel (Wako-gel C-300).
2,3,4,6-Tetra-O-benzyl-ꢀ-D-glucopyranosyl phenyl sulfone (2a). To a
solution of phenyl 2,3,4,6-tetra-O-benzyl-1-thio-ꢀ-D-glucopyranoside4 (500 mg,
0.79 mmol) in dry toluene (15 mL) was added, at room temperature, 70 % 3-
chloroperoxy benzoic acid ( 0.59 g, ca. 3.0 equiv). The reaction mixture was kept
for 2 h with stirring, then diluted with ethyl acetate (50 mL), washed with saturated
aq NaHSO3, 0.2 mol NaOH , water, and dried over MgSO4. After the solvent was
removed, the residue was recrystallized from ethanol to give 2a (480 mg, 92 %),
mp 111–112°C, [ꢀ]D ꢄ105°(c 0.13, acetone). 1H NMR ꢂ 3.44 (dd, 1H, J6a,6bꢅ11
Hz, J5,6aꢅ1.9 Hz, H-6a), 3.60–3.65 (m, 2H, H-4 and H-6b), 4.07 (dd, 1H, J1,2ꢅ6.0
Hz, J2,3ꢅ8.5 Hz, H-2), 4.32 (m, 1H, H5), 4.53 (t, 1H, J3,4ꢅ8.5 Hz, H-3), 4.30–4.96
(m, 8H, PhCH2ꢆ4 ), 4.94 ( d, 1H, H-1), 7.2–7.9 (m, 20H, Ph).
Anal. Calcd for C40H40O7S: C, 72.27 ; H,6.06. Found: C, 72.15 ; H, 6.23.
2,3,4,6-Tetra-O-benzyl-ꢀ-D-glucopyranosyl tert-butyl sulfone (2b). To
a solution of tert-butyl 2,3,4,6-tetra-O-benzyl-1-thio-ꢀ-D-glucopyranoside12 (250
mg, 0.41 mmol) in a mixture of acetic acid (5 mL) and ethyl acetate (5 mL) was
added 30 % hydrogen peroxide (1 mL), and the reaction solution was kept at room
temperature overnight. After TLC monitoring, the solution was poured into ice-
water, extracted with ethyl acetate (10 mL ꢆ 3). The organic layer was washed
with saturated aq NaHCO3, water, and dried over MgSO4, and concentrated in
vacuo to a crystalline residue (0.252 g), which was recrystallized from ethanol to
give white needles 2b (195 mg, 74 %), mp 122–123°C, [ꢀ]D ꢄ 87°(c 0.74, ace-
tone). 1H NMR ꢂ 1.47 (s,9H, CH3ꢆ3), 3.62–3.72 (m, 3H, H-4, H-6a, H-6b), 4.15
(dd, 1H, J1,2ꢅ5.3 Hz, J2,3ꢅ7.5 Hz, H-2), 424 (t, 1H, J3,4ꢅ7.5 Hz, J2,3ꢅ10.2 Hz, H-
3), 4.36, 4.39, 4.42, 4.45, 4.55, 4.58, 4.61, 4.62, 4.64, 4.66, 4.67, 4.76, 4.78, 4.89,
4.92 (m, 8H, Ph CH2 ꢆ 4), 4.50 (m, 1H, H-5), 7.2–7.40 (m, 20H, Ph).
Anal. Calcd for C38H44O7S: C, 70.78 ; H, 6.88 . Found: C, 70.69 ; H, 6.98.
1,5-Anhydro-3,4,6-tri-O-benzyl-2-deoxy-1-phenylsulfonyl-D-arabino-
hex-1-enitol (3). A mixture of 2,3,4,6-tetra-O-benzyl-ꢁ-D-glucopyranosyl
phenyl sulfone 14 (0.25 g, 0.38 mmol) and potassium tert-butoxide (45 mg, 1
equiv) in tert-butyl alcohol (15 mL) was heated to reflux for 15 min. The reaction
mixture was then deionised with Dowex HCR-W2 (Hꢄ), concentrated in vacuo to
a residue, which was subjected to flash column chromatography to give a crys-
talline product 3 (160 mg, 75 %), mp 83–84°C (lit.,4 mp 84–85°C).
Hydride reduction (A) of 2,3,4,6-tetra-O-benzyl-ꢁ-D-glucopyranosyl
phenyl sulfones (1): preparation of 3,4,6-tri-O-benzyl-1,2-dideoxy-1,5-anhy-
dro-D-arabino-hexitol (4) and 3,4,6-tri-O-benzyl-D-glucal (5). A mixture of
2,3,4,6-tetra-O-benzyl-ꢁ-D-glucopyranosyl phenylsulfone 1 (430 mg, 0.38 mmol)
and lithium aluminum hydride (106 mg, 2.8 mmol) in dry tetrahydrofuran (20 mL)