S. Tsegay et al. / Carbohydrate Research 357 (2012) 16–22
21
3.3.8. 2,6-Di-O-benzoyl-3,4-O-isopropylidene-
galactopyranosyl fluoride (2i)
a-
D-
3.3.11. Tolyl 2,3,4,6-tetra-O-benzoyl-1-thio-
mannopyranoside (R)S-S-oxide (1n)
a-D-
According to Section 3.3, 4-methylphenyl 2,6-di-O-benzoyl-3,4-
mCPBA (17 mg, 85%, 0.0837 mmol) in CH2Cl2 (1 mL) was added
dropwise to a solution of 4-methylphenyl 2,3,4,6-tetra-O-benzoyl-
O-isopropylidene-1-thio-b- -galactopyranoside (125 mg,
D
1i52
0.234 mmol) in (ClCH2)2 (2.5 mL) was treated with Xtalfluor-E
1-thio-a-D
-mannopyranoside 1a39 (53 mg, 0.075 mmol) in CH2Cl2
(89 mg, 0.39 mmol) at reflux for 15 min to give fluoride 2i
(2 mL) at ꢃ78 °C. After 15 min the reaction was quenched with
satd NaHCO3 then extracted with CH2Cl2 (2 ꢁ 5 mL). The combined
organic layers were washed with brine, dried and concentrated.
The crude was then purified by flash chromatography (30% ethyl
acetate/pet. spirit) to give the (R)-sulfoxide 1n (52 mg, 96%) as a
(86 mg, 85%) as a white solid: ½a D23
ꢂ
+75.6 (c 1.15, CHCl3); IR
m ;
(CH2Cl2)
1723, 1452, 1267, 1170, 1110, 1072, 709 cmꢃ1 1H
NMR (500 MHz): d 8.10–8.08 (m, 4H, Ph), 7.61–7.56 (m, 2H, Ph),
7.47–7.44 (m, 2H, Ph), 5.83 (dd, J1,2 3.0, J1,F 53.5 Hz, 1H, H1), 5.20
(ddd, J2,F 23.6, J1,2 3.0, J2,3 7.2 Hz, 1H, H2), 4.71–4.60 (m, 4H,
H3,5,6a,6b), 4.45 (d, J 5.2 Hz, 1H, H4), 1.58, 1.39 (2s, 6H, CMe2);
13C (125 MHz): d 166.5, 165.9, 133.7, 133.4, 130.1, 129.9, 129.3,
128.6, 128.6, 110.8, 104.6 (d, JC,F 225 Hz, 1C, C1), 73.0, 70.9, 70.7,
68.6, 68.6, 63.8, 27.8, 26.3 (2C, CMe2); HRMS (ESI) m/z calcd for
white solid: ½a 2D4
ꢂ
ꢃ131.7 (c 1.1, CHCl3); IR
m
1729, 1452, 1315,
1264, 1178, 1107, 1094, 1070, 1027, 709 cmꢃ1
;
1H NMR
(500 MHz): d 8.11–8.10 (m, 2H, Ar), 8.02–8.00 (m, 2H, Ar), 7.92–
7.90 (m, 2H, Ar), 7.86–7.84 (m, 2H, Ar), 7.70–7.68 (m, 2H, Ar),
7.60–7.52 (m, 3H, Ar), 7.44–7.33 (m, 9H, Ar), 7.30–7.25 (m, 2H,
Ar), 6.50 (dd, J1,2 2.0, J2,3 3.0 Hz, 1H, H2), 6.33 (dd, J2,3 3.0, J3,4
10,0 Hz, 1H, H3), 6.14 (dd, J3,4 = J4,5 10.0 Hz, 1H, H4), 5.32 (ddd,
J4,5 10.0, J5,6 2.0, 5.0 Hz, 1H, H5), 5.09 (d, J1,2 2.0 Hz, 1H, H1), 4.61
(dd, J5,6 2.0, J6,6 12.5 Hz, 1H, H6a), 4.53 (dd, J5,6 5.0, J6,6 12.5 Hz,
1H, H6b), 2.34 (s, 3H, CH3); 13C (125 MHz): d 166.2, 165.6, 165.3,
165.0, 142.7, 136.7, 133.7, 133.6, 133.3, 130.5, 130.1, 129.9,
129.9, 129.1, 128.9, 128.6, 128.4, 124.6, 94.8 (1C, C1), 94.7, 74.9,
70.6, 67.3, 67.2, 66.5, 63.0, 21.7 (1C, CH3); HRMS (ESI) m/z calcd
for C41H34O10SNa [M+Na]+ 741.1765, found 741.1763. The configu-
ration at sulfur was assigned as (R) based on analyzes of related
compounds.55
C
23H24FO7 [M+H]+ 431.1506, found 431.1495.
3.3.9. Hepta-O-acetyl-a-cellobiosyl fluoride (2j)
According to Section 3.3, 4-methylphenyl hepta-O-acetyl-1-
thio-b-cellobioside 1j53 (165 mg, 0.222 mmol) in (ClCH2)2
(2.5 mL) was treated with Xtalfluor-E (81 mg, 0.35 mmol) at reflux
for 30 min to give fluoride 2j (123 mg, 87%) as a white solid: ½a D23
ꢂ
+34.2 (c 0.42, CHCl3; lit.54 +30.6°); 1H NMR (500 MHz): d 5.65
(dd, J1,2 3.0, J1,F 53.5 Hz, 1H, H1), 5.45 (dd, J2,3 = J3,4 10.0 Hz, 1H,
H3), 5.14 (dd, J 9.0, 9.5 Hz, 1H, H30/40), 5.05 (dd, J 9.5, 10.0 Hz,
1H, H30/40), 4.92 (dd, J1,2 8.0, J2,3 9.5 Hz, 1H, H20), 4.86 (ddd, J2,F
24.0, J1,2 3.0, J2,3 10.0 Hz, 1H, H2), 4.55–4.52 (m, 1H, H6a), 5.53
(d, J1,2 8.0 Hz, 1H, H10), 4.34 (dd, J6,6 12.5, J5,6 4.5 Hz, 1H, H60a),
4.13 (dd, J6,6 12.5, J5,6 4.5 Hz, 1H, H6b), 4.09 (dd, J4,5 10.0, J5,6 1.5,
4.0 Hz, 1H, H5), 4.04 (dd, J6,6 12.5, J5,6 2.0 Hz, 1H, H60b), 3.82 (dd,
J3,4 = J4,5 10.0 Hz, 1H, H4), 3.66 (ddd, J4,5 9.5, J5,6 2.0, 4.5 Hz, 1H,
H50), 2.13, 2.08, 2.07, 2.03, 2.02, 2.00, 1.97 (7s, 21H, Ac); 13C
(125 MHz): d 170.6, 170.3, 170.3, 170.3, 169.6, 169.4, 169.0,
103.8 (d, JC,F 225 Hz, 1C, C1), 100.6, 75.5, 73.0, 72.2, 71.7, 70.8,
70.8, 70.6, 70.4, 68.9, 68.0, 61.8, 61.3, 20.9, 20.7, 20.7, 20.6, 20.6.
The spectral data were in agreement with those reported.54
3.3.12. Butyl 2,3,4,6-tetra-O-acetyl-1-thio-b-D-
galactopyranoside S-oxide (1o)
mCPBA (382 mg, 75%, 1.66 mmol) was added in one portion to a
solution of butyl 2,3,4,6-tetra-O-acetyl-thio-b- -galactopyranoside
D
1f47 (500 mg, 1.19 mmol) in CH2Cl2 (20 mL) at ꢃ78 °C. After 15 min
at ꢃ78 °C the reaction was warmed to ꢃ55 °C for 30 min, quenched
with satd NaHCO3 then extracted with CH2Cl2 (2 ꢁ 20 mL). The
combined organic layers were washed with brine, dried, and con-
centrated. The crude was then purified by flash chromatography
(60% ethyl acetate/pet. spirits) to give the sulfoxide 1o (3:1 mix-
ture of stereoisomers, 335 mg, 65%) as a white fluffy material:
HRMS (ESI) m/z calcd for C18H28O10SNa [M+Na]+ 459.1295, found
459.1294. Partial 1H NMR (400 MHz): d 5.65 (dd, J1,2 = J2,3 10.0,
1H, minor H2), 5.38 (dd, J1,2 = J2,3 10.2, 1H, major H2); 5.17 (dd,
J3,4 3.2, J2,3 10.0 Hz, 1H, minor H3); 5.12 (dd, J2,3 10.0, J3,4 3.2 Hz,
1H, major H3); 4.31 (d, J1,2 10.0, 1H, major H1), 2.16, 2.07, 2.04,
1.99 (4s, 4 ꢁ 3H, major Ac), 2.16, 2.07, 2.04, 2.00 (4s, 4 ꢁ 3H, minor
Ac), 0.971 (t, J 7.2, 3H, major CH3), 0.966 (t, J 7.2, 3H, minor CH3);
13C NMR (100 MHz): d 170.36, 170.34, 170.2, 170.0, 169.97, 168.8,
90.7 (1C, major C1), 87.48 (1C, minor C1), 75.7, 75.6, 72.0, 71.3,
67.00, 66.95, 65.8, 64.1, 61.5, 61.1, 47.2, 47.0, 24.9, 24.1, 22.2,
22.1, 20.80, 20.76, 20.73, 20.67, 20.66, 20.63, 20.59, 13.74, 13.71.
3.3.10. 2-O-Acetyl-3-O-(6-O-acetyl-2,3,4-tri-O-benzyl-a-D-
glucopyranosyl)-4,6-di-O-benzyl-a-D-mannopyranosyl fluoride
(2k)
According to Section 3.3, 4-methylphenyl 2-O-acetyl-3-O-(6-O-
acetyl-2,3,4-tri-O-benzyl- -glucopyranosyl)-4,6-di-O-benzyl-1-
thio-
-mannopyranoside 1k29 (41 mg, 0.042 mmol) in CH2Cl2
a
-D
a-D
(2 mL) was treated with Xtalfluor-E (17 mg, 0.074 mmol) at reflux
for 2 h to give fluoride 2k (17 mg, 45%) as a clear oil: ½a D22
ꢂ
+28.5 (c
1.25, CHCl3; lit.29 +30.6°); 1H NMR (500 MHz): d 7.34–7.13 (m, 25H,
Ph), 5.72–5.61 (dd, J1,2 2.0, J1,F 49.5 Hz, 1H, H1), 5.25 (dd, J1,2 2.0, J2,3
2.0 Hz, 1H, H20), 5.13 (d, J 12.0 Hz, 1H, benzyl-CH), 5.00 (d, J1,2
3.5 Hz, 1H, H10), 4.86 (d, J 12.0 Hz, 1H, benzyl-CH), 4.82 (d, J
10.5 Hz, 1H, benzyl-CH), 4.63 (d, J 12.5 Hz, 1H, benzyl-CH), 4.62
(d, J 12.0 Hz, 1H, benzyl-CH), 4.55 (d, J 12.5 Hz, 1H, benzyl-CH),
4.55 (d, J 10.0 Hz, 1H, benzyl-CH), 4.52 (d, J 11.5 Hz, 1H, benzyl-
CH), 4.47 (d, J 11.5 Hz, 1H, benzyl-CH), 4.27 (dd, J5,6 5.0, J6,6
12.0 Hz, 1H, H6a), 4.09 (dd, J5,6 2.0, J6,6 12.0 Hz, 1H, H6b), 4.05
(dd, J2,3 10.0, J3,4 9.0 Hz, 1H, H30), 4.03 (dd, J2,3 2.0, J3,4 2.0 Hz, 1H,
H3), 4.03 (dd, J3,4 9.5, J4,5 9.5 Hz, 1H, H4), 3.94–3.97 (m, 1H, H5),
3.87–3.91 (m, 1H, H50), 3.77 (dd, J5,6 4.0, J6,6 11.0 Hz, 1H, H60a),
3.68 (dd, J5,6 2.0, J6,6 11.0 Hz, 1H, H60b), 3.50 (dd, J1,2 3.5, J2,3
10.0 Hz, 1H, H20), 3.44 (dd, J3,4 9.0, J4,5 9.0 Hz, 1H, H40), 2.14, 2.03
(2 ꢁ s, 2 ꢁ 3H, Ac); 13C NMR (125 MHz): d 170.9, 170.2, 138.6,
138.5, 138.1, 138.0, 137.9, 128.6, 128.5, 128.4, 128.3, 128.1,
128.0, 127.9, 127.8, 127.6, 127.5, 104.7 (d, JC,F 212 Hz, 1C, C1),
99.8, 81.7, 79.6, 78.4, 75.8, 75.2, 75.1, 74.0, 73.6, 73.3, 73.2, 70.7,
70.4, 70.1, 68.4, 63.1, 21.2, 20.9. The spectral data were previously
reported in error;29 this report corrects the previous data.
Acknowledgements
We thank the Australian Research Council for financial support.
Supplementary data
Supplementary data associated with this article can be found, in
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