Y. Bai et al. / Carbohydrate Research 341 (2006) 1702–1707
1705
washed with satd aq NaHCO3 (3 · 20 mL), dried
(Na2SO4), and concentrated. Chromatography (4:1 hex-
anes–EtOAc) yielded 4 (354 mg, 90%) in a 1:3 a:b ratio
as a colorless syrup. Data for b anomer: Rf 0.67 (2:1 hex-
anes–EtOAc); [a]D ꢀ2.9 (c 2.0, CH2Cl2); 1H NMR
(500 MHz, CDCl3, dH): 8.04–8.01 (m, 2H, Ar), 7.98–
7.95 (m, 2H, Ar), 7.63–7.57 (m, 2H, Ar), 7.48–7.42 (m,
6H, Ar), 7.03 (d, 2H, J 8.3 Hz, Ar), 5.79 (d, 1H, J
3.2 Hz, H-4), 5.30 (dd, 1H, J 9.9, 9.9 Hz, H-2), 4.71
(d, 1H, J 9.9 Hz, H-1), 4.51 (dd, 1H, J 11.5, 7.1 Hz,
H-6), 4.38 (dd, 1H, J 11.5, 5.5 Hz, H-6), 4.14 (dd, 1H,
J 7.1, 5.5 Hz, H-5), 3.82 (dd, 1H, J 9.9, 3.2 Hz, H-3),
2.36 (s, 3H, tolyl CH3), 2.21 (s, 3H, acetyl CH3); 13C
NMR (125 MHz, CDCl3, dC): 169.31 (CO), 166.02
(CO), 165.34 (CO), 138.52 (Ar), 133.91 (Ar · 2),
133.69 (Ar), 133.28 (Ar), 130.17 (Ar · 2), 129.82
(Ar · 2), 129.62 (Ar · 2), 129.47 (Ar), 128.63 (Ar),
128.53 (Ar · 2), 128.42 (Ar · 2), 127.77 (Ar), 86.47 (C-
1), 75.64 (C-5), 68.54 (C-4), 68.52 (C-2), 63.33 (C-3),
62.51 (C-6), 21.26 (tolyl CH3), 20.94 (acetyl CH3); IR:
2109 cmꢀ1 (N3); ESIMS: m/z calcd for [C29H27N3O7S]-
Na+: 584.1462. Found: 584.1463.
3), 62.01 (C-6), 31.80 (octyl CH2), 29.43 (octyl CH2),
29.27 (octyl CH2), 25.84 (octyl CH2), 22.64 (octyl
CH2), 20.77 (acetyl CH3), 14.08 (octyl CH3); IR:
2107 cmꢀ1 (N3); ESIMS: m/z calcd for [C30H37N3O]-
Na+: 590.2473. Found 590.2472.
1.5. n-Octyl 3-azido-4,6-di-O-benzoyl-3-deoxy-b-D-
galactopyranoside (6)
Compound 5 (152 mg, 0.27 mmol) was dissolved in 50:1
CH3OH–AcCl (5.1 mL), and the solution was stirred for
24 h. The reaction mixture was quenched by the addi-
tion of satd aq NaHCO3 and then diluted with CH2Cl2
(20 mL). After being washed with water (20 mL) and a
satd NaCl solution (20 mL), the organic layer was dried
with Na2SO4 and concentrated. Chromatography (4:1
hexanes–EtOAc) gave 6 (130 mg, 92%) as a colorless
oil: Rf 0.73 (2:1 hexanes–EtOAc); [a]D +0.4 (c 1.5,
1
CH2Cl2); H NMR (500 MHz, CDCl3, dH): 8.12–8.09
(m, 2H, Ar), 8.05–8.01 (m, 2H, Ar), 7.62–7.55 (m, 2H,
Ar), 7.49–7.42 (m, 4H, Ar), 5.73 (dd, 1H, J 3.5,
1.0 Hz, H-4), 4.55 (dd, 1H, J 11.3, 6.6 Hz, H-6), 4.42
(d, 1H, J 7.7 Hz, H-1), 4.32 (dd, 1H, J 11.3, 6.5 Hz,
H-6), 4.09 (ddd, 1H, J 6.6, 6.5, 1.0 Hz, H-5), 3.99–3.93
(m, 2H, H-2, octyl OCH2), 3.71 (dd, 1H, J 10.3,
3.5 Hz, H-3), 3.59 (ddd, 1H, J 9.6, 7.0, 7.0 Hz, octyl
OCH2), 1.72–1.62 (m, 2H, octyl CH2), 1.40–1.23 (m,
10H, octyl CH2), 0.89 (t, 3H, J 7.0 Hz, octyl CH3);
13C NMR (125 MHz, CDCl3, dC): 166.05 (CO), 165.44
(CO), 133.57 (Ar), 133.27 (Ar), 130.11 (Ar · 2), 129.76
(Ar · 2), 129.50 (Ar), 128.99 (Ar), 128.51 (Ar · 2),
128.44 (Ar · 2), 103.38 (C-1), 72.07 (C-5), 70.96 (C-2),
70.67 (octyl OCH2), 68.30 (C-4), 63.30 (C-3), 62.12 (C-
6), 31.79 (octyl CH2), 29.56 (octyl CH2), 29.33 (octyl
CH2), 29.22 (octyl CH2), 25.93 (octyl CH2), 22.64 (octyl
CH2), 14.08 (octyl CH3); IR: 2110 cmꢀ1 (N3); ESIMS:
m/z calcd for [C28H35N3O7]Na+: 548.2367. Found:
548.2365.
1.4. n-Octyl 2-O-acetyl-3-azido-4,6-di-O-benzoyl-3-
deoxy-b-D-galactopyranoside (5)
To a mixture of 4 (262 mg, 0.47 mmol), n-octanol
˚
(88 lL, 0.56 mmol) and 4 A molecular sieves (100 mg)
in CH2Cl2 (15 mL), N-iodosuccinimide (332 mg,
1.40 mmol), and silver triflate (120 mg, 0.47 mmol) were
added in succession at 0 ꢁC. After stirring for 15 min at
0 ꢁC, the reaction mixture was warmed to room temper-
ature and stirred for 1 h. The reaction mixture turned
dark red, and Et3N was added, diluted with CH2Cl2
(25 mL), and filtered through Celite. The filtrate was
washed with satd aq Na2S2O3 (3 · 30 mL), dried
(Na2SO4) and concentrated to give a crude residue that
was purified by chromatography (4:1 hexanes–EtOAc)
to give 5 (208 mg, 78%) as a colorless oil: Rf 0.58 (3:1
1
hexanes–EtOAc); [a]D +14.2 (c 0.9, CH2Cl2); H NMR
1.6. p-Tolyl 3,4-di-O-acetyl-2,6-dideoxy-1-thio-a-L-lyxo-
hexopyranoside (8)
(500 MHz, CDCl3, dH): 8.14–8.12 (m, 2H, Ar), 8.04–
8.02 (m, 2H, Ar), 7.63–7.56 (m, 2H, Ar), 7.50–7.43 (m,
4H, Ar), 5.80 (dd, 1H, J 3.4, 1.0 Hz, H-4), 5.31 (dd,
1H, J 10.5, 7.9 Hz, H-2), 4.56 (dd, 1H, J 11.3, 6.6 Hz,
H-6), 4.54 (d, 1H, J 7.9 Hz, H-1), 4.33 (dd, 1H, J 11.3,
5.6 Hz, H-6), 4.11 (ddd, 1H, J 6.6, 5.6, 1.0 Hz, H-5),
3.92 (ddd, 1H, J 9.7, 6.2, 6.2 Hz, octyl OCH2), 3.78
(dd, 1H, J 10.5, 3.4 Hz, H-3), 3.52 (ddd, 1H, J 9.7,
6.8, 6.8 Hz, octyl OCH2), 2.14 (s, 3H, acetyl CH3),
1.65–1.54 (m, 2H, octyl CH2), 1.37–1.23 (m, 10H, octyl
CH2), 0.89 (t, 3H, J 7.0 Hz, octyl CH3); 13C NMR
(125 MHz, CDCl3, dC): 169.21 (CO), 166.06 (CO),
165.50 (CO), 133.68 (Ar), 133.29 (Ar), 130.20 (Ar · 2),
129.77 (Ar · 2), 129.46 (Ar), 128.75 (Ar), 128.58
(Ar · 2), 128.45 (Ar · 2), 101.58 (C-1), 71.97 (C-5),
70.28 (octyl OCH2), 70.20 (C-2), 68.35 (C-4), 62.12 (C-
To a solution of 3,4-di-O-acetyl-L-fucal (7)18 (0.32 g,
1.49 mmol) in CH3CN (10 mL), (NH4)2Ce(NO3)6
(0.41 g, 0.75 mmol) and p-thiocresol (0.92 g, 7.4 mmol)
were added at ꢀ78 ꢁC. The mixture was allowed to
warm to room temperature slowly over 4 h. The reaction
mixture was diluted with CH2Cl2 (30 mL) and then
washed with satd aq Na2S2O3 and satd aq NaHCO3 be-
fore being dried over MgSO4. The residue obtained after
concentration of the organic layer was purified by chro-
matography (9:1 hexanes–EtOAc) to give 8 (0.41 g,
81%) as a white solid: Rf 0.24 (6:1 hexanes–EtOAc);
[a]D ꢀ304.9 (c 1.4, CH3OH); 1H NMR (500 MHz,
CDCl3, dH): 7.34 (d, 2H, J 8.2 Hz, Ar), 7.12 (d, 2H, J
8.2 Hz, Ar), 5.66 (d, 1H, J 5.7 Hz, H-1), 5.31–5.26 (m,