Q. Yang et al. / Carbohydrate Research 342 (2007) 1175–1181
1179
CH@CH2), 97.0 (C-1), 77.6, 71.6, 71.4 (PhCH2), 68.1,
68.0 (CH2–CH@CH2), 20.9 (CH3CO), 17.7 (C-6); HRE-
SIMS: calcd for C18H24O6 [M+Na]+, 359.1471, found
m/z 359.1465. Anal. Calcd for C18H24O6: C, 64.27; H,
7.19. Found: C, 64.50; H, 7.21.
17.2 Hz, H-Z), 5.14 (dd, 1H, J 1.2, 10.4 Hz, H-E), 4.86
(d, 1H, J 2.0 Hz, H-1), 4.82 (dd, 1H, J 1.6, 3.2 Hz,
H-2), 4.36 (d, 1H, J 11.6 Hz, PhCH2), 4.24 (d, 1H, J
11.6 Hz, PhCH2), 4.07–4.11 (m, 1H, CH2–CH@CH2),
3.87–3.92 (m, 1H, CH2–CH@CH2), 3.68 (dd, 1H, J
3.2, 9.6 Hz, H-3), 3.64 (dd, 1H, J 6.4, 9.6 Hz, H-5),
3.51 (t, 1H, J 9.6 Hz, H-4), 2.30 (s, 3H, CH3 of Ts),
1.25 (d, 3 H, J 6.4 Hz, H-6); 13C NMR (100 MHz,
CDCl3): d 144.5, 137.3, 133.3, 133.1 (CH2–CH@CH2),
129.4, 128.0, 127.6, 127.4, 127.4, 117.3 (CH2–
CH@CH2), 96.4 (C-1), 76.5, 75.1, 71.0 (PhCH2), 68.1,
67.7 (CH2–CH@CH2), 21.2 (CH3 of Ts), 17.2 (C-6);
HRESIMS: calcd for C23H28SO7 [M+Na]+, 471.1453,
found m/z 471.1448. Anal. Calcd for C23H28SO7: C,
61.59; H, 6.29. Found: C, 61.46; H, 6.40.
3.2.6. Allyl 2-O-benzoyl-3-O-benzyl-a-L-rhamnopyran-
oside (2b). From 2 (66.5 mg), colorless syrup (70.2
21
mg, 78%): ½aꢁD +36.7 (c 0.99, CHCl3); 1H NMR
(400 MHz, CDCl3): d 7.42–8.08 (m, 5 H, PhH of Bz),
7.23–7.30 (m, 5H, PhH of Bn), 5.92 (ddt, 1H, J 5.6,
10.8, 16.8 Hz, CH2–CH@CH2), 5.61 (dd, 1H, J 2.0,
3.2 Hz, H-2), 5.31 (ddd, 1H, J 1.6, 3.2, 17.2 Hz, H-Z),
5.22 (ddd, 1H, J 1.2, 2.8, 10.4 Hz, H-E), 4.94 (dd, 1H,
J 1.6 Hz, H-1), 4.78 (d, 1H, J 11.2 Hz, PhCH2), 4.45
(d, 1H, J 11.2 Hz, PhCH2), 4.18–4.23 (m, 1H, CH2–
CH@CH2), 3.99–4.04 (m, 1H, CH2–CH@CH2), 3.87
(dd, 1H, J 3.2, 9.2 Hz, H-3), 3.81 (dd, 1H, J 6.4,
9.6 Hz, H-5), 3.70 (dd, 1H, J 9.2, 9.6 Hz, H-4), 1.37
(d, 3H, J 6.4 Hz, H-6); 13C NMR (50 MHz, CDCl3): d
165.7 (PhCO), 137.5, 133.5 (CH2–CH@CH2), 133.2,
129.8, 129.7, 128.4, 128.3, 128.0, 127.8, 117.6 (CH2–
CH@CH2), 97.0 (C-1), 77.8, 71.9, 71.3 (PhCH2), 68.6,
68.2, 68.0 (CH2–CH@CH2), 17.8 (C-6); HRESIMS:
calcd for C23H26O6 [M+Na]+, 421.1627, found m/z
421.1622. Anal. Calcd for C23H26O6: C, 69.33; H, 6.58.
Found: C, 69.45; H, 6.68.
3.3. Benzyl 2,3,4-tri-O-benzoyl-b-D-xylopyranosyl-
(1!3)-2,4-di-O-benzoyl-a-D-xylopyranoside (6)
The donor 3 (1.99 g, 3.28 mmol) and the acceptor 4
(1.40 g, 3.12 mmol) were dried together under high vac-
uum for 2 h, then dissolved in CH2Cl2 (31 mL), followed
˚
by freshly activated 4 A MS (5.2 g), after which it was
cooled to ꢀ40 ꢁC and a soln of TMSOTf (126 lL,
0.656 mmol) in CH2Cl2 (26 mL) was added dropwise.
The reaction mixture was stirred for 3 h at the same tem-
perature, then neutralized with satd aq NaHCO3, con-
centrated, and purified by column chromatography
(5:1, petroleum ether–EtOAc) to afford 6 as a colorless
syrup (2.08 g, 75%): Rf 0.38 (3:1, petroleum ether–
3.2.7. Allyl 3-O-benzyl-2-O-chloroacetyl-a-L-rhamno-
pyranoside (2c). From 2 (82.7 mg), colorless syrup
21
21
1
(70.8 mg, 68%): ½aꢁD ꢀ3.7 (c 1.27, CHCl3); H NMR
(400 MHz, CDCl3): d 7.29–7.38 (m, 5H, PhH of Bn),
5.89 (m, 1H, J 5.6, 10.8, 16.8 Hz, CH2–CH@CH2),
5.42 (dd, 1H, J 1.6, 3.2 Hz, H-2), 5.29 (dd, 1H, J 1.2,
16.8 Hz, H-Z), 5.23 (dd, 1H, J 1.2, 10.4 Hz, H-E), 4.83
(d, 1H, J 1.2 Hz, H-1), 4.72 (d, 1H, J 10.8 Hz, PhCH2),
4.42 (d, 1H, J 10.8 Hz, PhCH2), 4.16–4.20 (m, 1H, CH2–
CH@CH2), 3.97–4.02 (m, 1H, CH2–CH@CH2), 4.13 (s,
2H, ClCH2CO), 3.78 (dd, 1H, J 3.2, 9.6 Hz, H-3), 3.72
(dd, 1H, J 6.0, 9.6 Hz, H-5), 3.52 (t, 1H, J 9.6 Hz, H-
4), 1.32 (d, 3H, J 6.0 Hz, H-6); 13C NMR (100 MHz,
CDCl3): d 166.8 (ClCH2CO), 137.4, 133.3 (CH2–
CH@CH2), 128.6, 128.2, 128.1, 127.9, 117.9 (CH2–
CH@CH2), 96.5 (C-1), 77.6, 71.7 (PhCH2), 71.6, 70.0,
68.2, 68.1 (CH2–CH@CH2), 40.8 (ClCH2CO), 17.6 (C-
6); HRESIMS: calcd for C18H23O6Cl [M+Na]+,
393.1081, found m/z 393.1067. Anal. Calcd for
C18H23O6Cl: C, 58.30; H, 6.25. Found: C, 58.38; H,
6.18.
EtOAc); ½aꢁD ꢀ2.1 (c 1.40, CHCl3); 1H NMR
(400 MHz, CDCl3): d 7.88–8.13 (m, 5H, PhH), 7.09–
7.62 (m, 20H, PhH), 5.64 (dd, 1H, J 6.0 Hz, H-30),
5.31–5.38 (m, 1H, H-4), 5.26 (d, 1H, J 4.4 Hz, H-10),
5.18 (d, 1H, J 3.6 Hz, H-1), 5.11 (dd, 1H, J 3.6 Hz,
9.6 Hz, H-20), 5.03 (dd, 1H, J 5.2, 9.2 Hz, H-40), 4.75
(d, 1H, J 12.0 Hz, PhCH2), 4.69 (dd, 1H, J 9.6 Hz, H-
3), 4.47 (d, 1H, J 12.0 Hz, PhCH2), 4.28 (dd, 1H, J
3.6, 12.4 Hz, H-5e0), 4.06 (dd, 1H, J 6.0, 10.8 Hz, H-
5e), 3.84 (t, 1H, J 10.8 Hz, H-5a), 3.58 (dd, 1H, J 5.2,
12.4 Hz, H-5a0); 13C NMR (100 MHz, CDCl3): d
165.5, 165.3, 165.2, 165.0, 164.5 (PhCO), 133.4, 133.3,
133.2, 133.1, 132.8, 129.8, 129.8, 129.6, 129.5, 129.2,
128.9, 128.8, 128.5, 128.4, 128.3, 128.2, 128.1, 128.0,
127.8, 127.6, 100.5, 95.2 (C-1), 75.3, 73.8, 70.3, 69.7
(PhCH2), 69.5, 68.7, 68.5, 60.3, 59.0; HRESIMS: calcd
for C52H44O14 [M+Na]+, 915.2629, found m/z
915.2590. Anal. Calcd for C52H44O14: C, 69.95; H,
4.97. Found: C, 70.08; H, 5.06.
3.2.8. Allyl 3-O-benzyl-2-O-(p-tolylsulfonyl)-a-L-rhamno-
pyranoside (2d). From 2 (55.8 mg), white foamy solid
3.4. 2,3,4-Tri-O-benzoyl-b-D-xylopyranosyl-(1!3)-2,4-
di-O-benzoyl-D-xylopyranosyl trichloroacetimidate (7)
21
1
(56.1 mg, 66%): ½aꢁD +38.7 (c 1.29, CHCl3); H NMR
(400 MHz, CDCl3): d 7.23–7.77 (m, 5H, PhH of Ts),
7.13–7.29 (m, 5H, PhH of Bn), 5.80 (ddt, 1H, J 5.6,
10.8, 16.8 Hz, CH2–CH@CH2), 5.20 (dd, 1H, J 1.6,
To a soln of 6 (1.72 g, 1.93 mmol) in EtOH (48 mL) was
added 10% Pd/C (516 mg). The mixture was stirred at
50 ꢁC for 24 h, at the end of which time TLC indicated