6.97 (2 H, d, J 8.8, arom. H), 6.49 (1 H, d, J 15.9, -CH CH–Ph),
6.12 (1 H, ddd, J 15.9 and 2 ¥ 7.5, -CH2–CH ), 3.89 (1 H, ddd,
J8,7 8.6, J8,9b 6.2, J8,9a 2.7, H-8), 3.90–3.84 (1 H, m, H-9a), 3.83 (3
H, s, arom. OCH3), 3.83–3.78 (1 H, m, H-5), 3.74 (1 H, ddd, J4,3ax
11.7, J4,5 10.0, J4,3eq 4.6, H-4), 3.66 (1 H, dd, J6,5 10.2, J6,7 1.5, H-6),
3.66–3.62 (1 H, m, H-9b), 3.59 (1 H, dd, J7,8 8.6, J7,6 1.5, H-7), 2.66
(1 H, dd, J3eq,3ax 13.0, J3eq,4 4.6, H-3eq), 2.65–2.64 (2 H, m, -CH2–
CH ), 2.05 (3 H, s, AcCH3), 1.69 (1 H, dd, J3ax,3eq 13.0, J3ax,4 11.7,
H-3ax); dC (100 MHz, D2O) 176.75 (C O), 132.95 (-CH CH–
Ph), 130.37 (arom. C), 127.58 (arom. C), 121.67 (-CH2–CH ),
114.32 (arom. C), 81.01 (C-2), 73.76 (C-6), 71.90 (C-8), 68.38,
68.35 (C-4, C-7), 62.80 (C-9), 55.43 (arom. OCH3), 52.24 (C-5),
43.05 (-CH2–CH ), 39.71 (C-3), 22.06 (AcCH3); MS (MALDI-
TOF): m/z = 440.5 ([M+H]+), 462.4 ([M+Na]+), 478.4 ([M+K]+);
MS (FAB): m/z = 462.3 ([M+Na]+), 478.3 ([M+K]+).
(1 H, dd, J7,8 9.7, J7,6 1.1, H-7), 2.54–2.42 (3 H, m, CH2, H-3eq),
1.99 (3 H, s, AcCH3), 1.54 (1 H, dd, J3ax,3eq 12.8, J3ax,4 11.9, H-3ax);
dC (125 MHz, [D4]MeOH) 133.41 (-CH CH2), 129.50, 128.84,
127.50 (arom. C), 118.89 (-CH CH2), 102.24 (PhCH), 81.77
(C-2), 80.78 (C-7), 73.16 (C-6), 72.62 (C-9), 69.76 (C-4), 61.36
(C-8), 52.75 (C-5), 52.55 (OCH3), 45.58 (CH2), 41.11 (C-3), 22.93
(AcCH3); HRMS (FAB): m/z calcd. for [M+H]+: 436.197142;
found: 436.197968.
Methyl-5-acetamido-2,6-anhydro-9-O-benzyl-3,5-dideoxy-2-C-
(prop-2-enyl)-D-erythro-L-manno-nononate (21). Compound 19
(160 mg, 367 mmol), trimethyl amine borane adduct (0.11 g,
1.5 mmol) and aluminium chloride (294 mg, 2.20 mmol) were
dissolved in 8.4 mL dry tetrahydrofuran. After stirring for 5 min
water (9.9 mL, 0.55 mmol) was added and the reaction was
stirred at room temperature for 4 h. After TLC showed complete
consumption of starting material the reaction was stopped by
adding water (4.2 mL) and 0.1 molar HCl (4.2 mL). The solution
was diluted with dichloromethane (42 mL) and washed twice with
5% sodium bicarbonate solution (2 ¥ 20 mL) and with water
(20 mL). The organic phase was dried over sodium sulphate,
filtrated and concentrated in vacuo. The residue was purified by
column chromatography (dichloromethane/methanol) to give 21
Methyl-5-acetamido-2,6-anhydro-8,9-O-benzyliden-3,5-dide-
oxy-2-C-(prop-2-enyl)-D-erythro-L-manno-nononate (19) and
methyl-5-acetamido-2,6-anhydro-7,9-O-benzyliden-3,5-dideoxy-2-
C-(prop-2-enyl)-D-erythro-L-manno-nononate (20). Compound
6 (200 mg, 0.576 mmol) and benzaldehyde dimethyl acetal
(173 mL, 1.15 mmol) were dissolved in dry acetonitrile. The
solution was cooled to 0 ◦C and a catalytic amount (8 mg,
0.04 mmol) of p-toluenesulfonic acid monohydrate was added.
The reaction was stirred at room temperature until TLC showed
complete consumption of the starting material. After adding a
few drops of triethyl amine the solvent was removed in vacuo
and the products were separated by column chromatography
(dichloromethane/methanol); 19 (143 mg, 57%, 1 : 1 mixture
◦
(82 mg, 51%) as a white solid; mp 101 C; [a]2D5 -104 (c 0.2 in
CH2Cl2); dH (500 MHz, [D4]MeOH) 7.38–7.31 (5 H, m, arom. H),
5.84–5.74 (1 H, m, CH CH2), 5.11–5.06 (2 H, m, CH CH2),
4.59–4.57 (2 H, m, PhCH2), 3.97 (1 H, ddd, J8,7 8.8, J8,9b 5.7, J8,9a
2.3, H-8), 3.78 (1 H, dd, J9a,9b 10.3, J9a,8 2.3, H-9a), 3.75 (3 H, s,
OCH3), 3.70 (1 H, dd, J5,4 10.2, J5,6 10.2, H-5), 3.65–3.58 (1 H,
m, H-4), 3.62 (1 H, dd, J9b,9a 10.3, J9b,8 5.7, H-9b), 3.55 (1 H, dd,
J7,8 8.8, J7,6 1.4, H-7), 3.51 (1 H, dd, J6,5 10.2, J6,7 1.4, H-6), 2.57
(1 H, dd, J3eq,3ax 13.2, J3eq,4 4.6, H-3eq), 2.54–2.44 (2 H, m, CH2),
1.98 (3 H, s, AcCH3), 1.45 (1 H, dd, J3ax,3eq 13.2, J3ax,4 11.4, H-3ax);
dC (100 MHz, [D4]MeOH) 175.22 (C-1), 139.85 (arom C), 132.94
(-CH CH2), 129.33 (arom. C), 128.84 (arom. C), 128.59 (arom.
C), 119.37 (-CH CH2), 81.75 (C-2), 75.78 (C-6), 74.41 (PhCH2),
72.90 (C-9), 71.82 (C-8), 70.16 (C-7), 69.04 (C-4), 54.17 (C-5),
52.95 (OCH3), 45.71 (CH2), 41.45 (C-3), 22.63 (AcCH3); HRMS
(FAB): m/z calcd. for [M+H]+: 438.212792; found: 438.211823.
◦
of diastereomers): mp 112 C; [a]2D5 +83 (c 0.1 in CH2Cl2); dH
(500 MHz, [D4]MeOH) 7.50–7.46 (2 H, m, arom. H), 7.38–7.35
(3 H, m, arom. H), 5.87 (0.5 H, s, PhCHI), 5.85–5.74 (2 H, m,
I
CH CH2 , CH CH2II), 5.76 (1 H, s, PhCHII), 5.12–5.06 (4 H,
I
m, CH CH2 , CH CH2II), 4.40–4.34 (2 H, m, H-8), 4.27 (1 H,
dd, J9a,9b 8.5, J9a,8 6.7, H-9aI), 4.24 (1 H, dd, J9a,9b 8.3, J9a,8 5.2,
H-9aII), 4.11 (1 H, dd, J9b,9a 8.5, J9b,8 7.6, H-9bI), 4.09 (1 H, dd,
J9b,9a 8.3, J9b,8 7.3, H-9bII), 3.82 (1 H, dd, J7,8 5.2, J7,6 1.1, H-7I),
3.75 (1 H, dd, J5,4 10.2, J5,6 10.2, H-5I), 3.74 (1 H, dd, J5,4 10.2,
J5,6 10.2, H-5II), 3.69–3.59 (3 H, m, H-7II, H-4I, H-4II), 3.66 (3
H, s, OCH3), 3.65 (3 H, s, OCH3), 3.50 (1 H, dd, J6,5 10.2, J6,7
1.1, H-6II), 3.47 (1 H, dd, J6,5 10.2, J6,7 1.1, H-6I), 2.56–2.44 (6
5-Acetamido-2,6-anhydro-9-O-benzyl-3,5-dideoxy-2-C-(prop-
2-enyl)-D-erythro-L-manno-nononic acid (22). Compound 21
(62 mg, 0.14 mmol) was saponified according to GP4 to give 22
(60 mg, 100%) as a white solid; mp 147 ◦C; [a]D25 -22 (c 0.1 in H2O);
I
H, m, CH2 , CH2II, H-3eqI, H-3eqII), 2.01 (3 H, s, AcCH3), 1.98 (3
H, s, AcCH3), 1.54 (1 H, dd, J3ax,3eq 12.8, J3ax,4 11.7, H-3ax), 1.53 (1
H, dd, J3ax,3eq 12.8, J3ax,4 11.7, H-3ax); dC (125 MHz, [D4]MeOH)
139.59 (arom. C), 133.21, 133.16 (-CH CH2), 130.31, 130.14,
129.23, 127.97, 127.68 (arom. C), 119.26, 119.17 (-CH CH2),
105.08 (PhCHII), 104.84 (PhCHI), 81.99, 81.88 (C-2), 78.11,
77.92 (C-8), 76.72, 76.31 (C-6), 70.93, 70.89 (C-7), 69.07, 68.92
(C-4), 68.59, 68.48 (C-9), 54.11 (C-5), 52.46, 52.43 (OCH3), 45.64,
45.61 (CH2), 41.27 (C-3), 22.72 (AcCH3); HRMS (FAB): m/z
calcd. for [M+H◦]+: 436.197142; found: 436.197968; 20 (88 mg,
35%): mp 83–84 C; [a]2D5 -21.4 (c 0.5 in MeOH); dH (500 MHz,
[D4]MeOH) 7.59–7.56 (2 H, m, arom. H), 7.37–7.30 (3 H, m,
arom. H), 5.88–5.75 (1 H, m, CH CH2), 5.43 (1 H, s, PhCH),
5.07–5.03 (2 H, m, CH CH2), 4.27 (1 H, dd, J9a,9b 10.6, J9a,8 5.4,
H-9a), 4.04 (1 H, ddd, J8,9b 10.0, J8,7 9.7, J8,9a 5.4, H-8), 4.02 (1
H, dd, J5,6 10.5, J5,4 10.3, H-5), 3.87 (1 H, dd, J6,5 10.5, J6,7 1.1,
H-6), 3.74 (3 H, s, OCH3), 3.60 (1 H, ddd, J4,3ax 11.9, J4,5 10.3,
J4,3eq 4.7, H-4), 3.56 (1 H, dd, J9b,9a 10.6, J9b,8 10.0, H-9b), 3.55
d
H (500 MHz, [D4]MeOH) 7.37–7.23 (5 H, m, arom. H), 5.94–5.85
(1 H, m, CH CH2), 5.08–4.99 (2 H, m, CH CH2), 4.59 (1 H, d,
J 12.3, PhCH2a), 4.54 (1 H, d, J 12.3, PhCH2b), 3.99 (1 H, ddd,
J8,7 8.8, J8,9b 5.7, J8,9a 2.2, H-8), 3.76 (1 H, dd, J9a,9b 10.4, J9a,8 2.2,
H-9a), 3.70 (1 H, ddd, J4,3ax 11.4, J4,5 9.8, J4,3eq 4.7, H-4), 3.61 (1
H, dd, J5,6 0.4, J5,4 9.8, H-5), 3.60 (1 H, dd, J9b,9a 10.4, J9b,8 5.7,
H-9b), 3.54 (1 H, dd, J6,5 10.4, J6,7 1.9, H-6), 3.52 (1 H, dd, J7,8 8.8,
J
7,6 1.9, H-7), 2.63 (1 H, dd, J3eq,3ax 12.6, J3eq,4 4.7, H-3eq), 2.48-2.38
(2 H, m, CH2), 1.99 (3 H, s, AcCH3), 1.45 (1 H, dd, J3ax,3eq 12.6,
J3ax,4 11.4, H-3ax); dC (125 MHz, [D4]MeOH) 175.47 (AcC O),
134.62 (CH CH2), 129.29 (arom. C), 128.80 (arom. C), 128.51
(arom. C), 117.87 (CH CH2), 75.31 (C-6), 74.30 (PhCH2), 72.75
(C-9), 71.98 (C-8), 70.34 (C-7), 69.78 (C-4), 54.47 (C-5), 45.95
(CH2), 42.16 (C-3), 22.54 (AcCH3); HRMS (FAB): m/z calcd. for
[M+H]+: 424.197142; found: 424.196808.
4494 | Org. Biomol. Chem., 2011, 9, 4487–4497
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The Royal Society of Chemistry 2011
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