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Z. Yang et al. / Carbohydrate Research 329 (2000) 879–884
3,4,6-Tri-O-acetyl-1,2-(allyl 4,6-O-benzyli-
dene-3-O-tert-butyldimethylsilyl-2-yl-h- -glu-
copyranosid-2-yloxy-1-ethylidene)-h- -galac-
9.3, J2,1 3.9 Hz, H-2), 4.20 (m, 3 H, H-3, H-6,
OCHaHbCHCH2), 3.90 (m, 2 H, OCHaHbCH-
CH2, H-5), 3.71 (t, 1 H, J6%,6 =J6%,5 10.3 Hz,
H-6%), 3.50 (t, 1 H, J4,5=J4,3 9.3 Hz, H-4),
1.22 (s, 9 H, t-BuCO), 0.79 (s, 9 H, t-BuSi),
0.00 (2s, 2 Me). EIMS (m/z, %): 505 [M+−1,
1], 449 [M+−OAll, 33], 391 [M]+−TBDMS,
7]. Anal. Calcd for C27H42O7Si: C, 64.00; H,
8.35. Found: C, 63.66; H, 8.60.
D
D
topyranose (5). To a stirred suspension of
sugar alcohol 3 (22 mg, 0.052 mmol), imidate
,
1 (28 mg, 0.057 mmol) and 4 A MS (ꢀ40 mg)
in dry CH2Cl2 (2 mL) at −78 °C, was added
Me3SiOTf (0.1 equiv) for 0.5 h. The mixture
was quenched with Et3N and then filtered and
concentrated. The residue was applied to a
silica gel column (10:1–3:1 petroleum ether–
EtOAc) to give 5 (35 mg, 89%) as a white
solid: Rf 0.53 (2:1 petroleum ether–EtOAc);
Allyl 4,6-O-benzylidene-3-O-tert-butyldi-
methylsilyl-h- -glucopyranoside (3). To a solu-
D
tion of 13 (24.8 g, 48.9 mmol) in dry CH2Cl2
(50 mL) was added DIBAL-H (99 mL, 97.7
mmol, 1.0 M in hexanes) at −78 °C. The
solution was stirred at −78 to −10 °C for 3
h, then quenched with MeOH (20 mL) and
diluted with EtOAc. The organic phase was
washed sequentially with aq HCl (5%), satd aq
NaHCO3, and brine, and then dried over
Na2SO4 and concentrated in vacuo. The residue
was purified by column chromatography on
silica gel (15:1 petroleum ether–EtOAc) to
give 3 (19.6 g, 95%) as a syrup: Rf 0.43 (8:1
petroleum ether–EtOAc); [h]2D2 +74.8° (c
1
[h]2D2 +68.4° (c 1.05, CHCl3); H NMR (300
MHz, CDCl3): l 7.45–7.33 (m, 5 H), 5.94 (m,
1 H), 5.77 (d, 1 H, J1,2 4.7 Hz), 5.49 (s, 1 H,
PhCH), 5.42 (t, 1 H, J 2.6), 5.36–5.19 (m, 2
H), 5.02 (m, 2 H), 4.34–3.98 (m, 8 H), 3.82
(m, 1 H), 3.69 (t, 1 H, J 10.2 Hz), 3.58 (dd, 1
H, J 3.6, J 8.8 Hz), 3.43 (t, 1 H, J 9.5 Hz),
2.10, 2.07, 2.05, 1.70 (each s, each 3 H), 0.82
(s, 9 H), 0.06, 0.00 (each s, each 3 H). EIMS
(m/z, %): 423 [M+−Gal, 3], 331 (Gal, 93).
Anal. Calcd for C36H52O15Si: C, 57.43; H,
6.96. Found: C, 57.43; H, 7.00.
1
0.82, CHCl3); H NMR (300 MHz, CDCl3): l
3,4,6-Tri-O-acetyl-1,2-(propyl 4,6-O-benzyli-
dene-3-O-tert-butyldimethylsilyl-h-
pyranosid-2-yloxy-1-ethylidene)-h-
D
-gluco-
-gluco-
7.51–7.33 (m, 5 H), 5.94 (m, 1 H), 5.50 (s, 1
H, PhCH), 5.36–5.22 (m, 2 H), 4.95 (d, 1 H,
J1,2 4.0 Hz, H-1), 4.26 (dd, J6,6% 9.9, J6,5 4.5 Hz,
H-6), 4.22 (m, 1 H), 4.10–4.03 (m, 1 H), 3.90
(t, 1 H, J3,2 8.6 Hz, H-3), 3.82 (m, 1 H, H-5),
3.72 (t, 1 H, J6%,6=J6%,5 10.1 Hz, H-6%), 3.58
(dd, 1 H, J2,3 8.8, J2,1 3.9 Hz, H-2), 3.43 (t, 1
H, J4,3 9.1 Hz, H-4), 0.87 (s, 9 H), 0.10 and
0.03 (2s, 6 H); Anal. Calcd for C22H34O6Si: C,
62.50; H, 8.11. Found: C, 62.53; H, 8.34.
Propyl 4,6-O-benzylidene-3-O-tert-butyldi-
D
pyranose (6). A procedure similar to the
preparation of orthoester 5 was employed. 6:
Rf 0.43 (2:1 petroleum ether–EtOAc); [h]D22
1
+35.9° (c 1.00, CHCl3); H NMR (300 MHz,
CDCl3): l 7.52–7.32 (m, 5 H), 5.53 (d, 1 H,
J1%,2 5.1 Hz, H-1%), 5.49 (s, 1 H, PhCH), 5.22–
5.21 (m, 1 H), 4.98 (d, 1 H, J1,2 3.7 Hz, H-1),
4.93–4.89 (m, 1 H), 4.49–4.46 (m, 1 H), 4.37–
4.11 (m, 3 H), 3.97–3.89 (m, 2 H), 3.81–3.62
(m, 3 H), 3.60–3.50 (m, 1 H), 3.40 (t, 1 H, J
8.92), 3.32–3.23 (m, 1 H), 2.12 (s, 9 H), 1.78
(s, 3 H), 1.62 (m, 2 H), 0.98 (t, 3 H), 0.82 (s,
9 H), 0.06, 0.00 (each s, each 3 H). ESIMS
(m/z): 778 [M++Na]. Anal. Calcd for
C36H54O15Si: C, 57.28; H, 7.21. Found: C,
57.24; H, 7.25.
methylsilyl-h- -glucopyranoside (4). A proce-
D
dure similar to the preparation of allyl gly-
coside 3 was employed. Data for 4: Rf 0.43
(8:1 petroleum ether–EtOAc); [h]2D2 +70.6° (c
1
1.05, CHCl3); H NMR (300 MHz, CDCl3): l
7.48–7.35 (m, 5 H, Ph), 5.51 (s, 1 H, PhH),
4.88 (d, 1 H, J1,2 4.12 Hz, H-1), 4.26 (dd, 1 H,
J 4.40, J 9.61), 3.86 (t, 1 H, J 8.93), 3.82–3.64
(m, 3 H), 3.59–3.38 (m, 3 H), 2.06 (s, 1 H,
OH), 1.65 (m, 2 H, OCH2CH2CH3), 0.96 (t, 3
H, OCH2CH2CH3); 0.89 (s, 9 H, t-BuSi), 0.11,
0.04 (2s, each 3 H, Me2Si). EIMS (m/z, %):
425 [M+, 1.2]. Anal. Calcd for C22H36O6Si: C,
62.23; H, 8.55. Found: C, 62.11; H, 8.51.
Allyl
pyranosyl-(12)-4,6-O-benzylidene-3-O-tert-
butyldimethylsilyl-h-
2,3,4,6-tetra-O-acetyl-i- -galacto-
D
D-glucopyranoside (7). To
a stirred suspension of sugar alcohol 3 (39 mg,
0.092 mmol), imidate 1 (55 mg, 0.11 mmol),
,
and 4 A MS (ꢀ50 mg) in dry CH2Cl2 (3 mL)
at rt, was added a toluene solution of AgOTf
(0.25 equiv). After being stirred overnight, the