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L. Ackermann et al. / Tetrahedron 56 (2000) 2195±2202
starting from substrate 23 (4.95 g, 6.81 mmol). Colorless
crystals (6.71 g, 91%). mp142±1438C 1H NMR
(300 MHz, CD2Cl2) d 3.43 (4H, d, J5.3 Hz), 3.76 (6H,
s), 3.98 (2H, m), 4.06 (2H, m), 4.40±4.65 (8H, m), 6.78
(4H, dt, J8.9, 2.5 Hz), 7.11 (4H, m), 7.29 (32H, m), 7.46
(8H, m); 13C NMR (75 MHz, CD2Cl2) d 55.5, 63.8, 72.9,
74.1, 78.8, 79.3, 86.9, 113.4, 127.1, 127.2, 127.6, 127.7,
127.9, 128.0, 128.2, 128.5, 128.6, 128.7, 128.8, 130.7,
135.9, 139.2, 139.3, 145.1, 159.0; IR: 3086, 3058, 3032,
2933, 2888, 2861, 2836, 1607, 1584, 1510, 1496, 1448,
1393, 1334, 1301, 1252, 1217, 1177, 1155, 1126, 1091,
1068, 1030, 1002, 987, 946, 901, 828, 797, 765, 736, 697,
632, 584; MS (EI) m/z (rel. intensity) 1086 ([M1], ,0.1),
363 (9), 273 (100), 91 (55).
dropwise (5 min) to a solution of oxalyl chloride (360 ml,
3.8 mmol) in CH2Cl2 (4 mL) at 2608C. The solution is
stirred for 2 min before diol 13 (500 mg, 0.92 mmol)
dissolved in CH2Cl2 (4 mL) is introduced during 5 min at
the same temperature. After stirring the resulting mixture
for an additional 10 min, Et3N (2.4 mL, 17.2 mmol) is
added at 2608C. The reaction mixture is kept at 2608C
for 15 min and is then allowed to warm to ambient tempera-
ture. The reaction is diluted with CH2Cl2 (100 mL), the
organic phase is successively washed with aq. HCl
(0.05 M, 2£20 mL), water (20 mL) and brine (2£20 mL),
dried (Na2SO4) and evaporated. Crude dialdehyde 14 thus
obtained is used in the next step without further puri®cation.
The commercially available Tebbe reagent (,0.5 M in tolu-
ene, 0.4 mmol, 0.8 mL) is diluted with THF (5 mL) and the
resulting solution is added dropwise over a period of 2 h to a
cooled solution (2408C) of the crude dialdehyde 14
(100 mg, 0.185 mmol) and pyridine (0.1 mL) in THF
(10 mL). The reaction mixture is slowly warmed to ambient
temperature and stirred for 30 min. The reaction is quenched
by addition of a few drops of aq. NaOH (2N) at 2108C, the
mixture is stirred for 20 min, insoluble residues are ®ltered
off through a pad of celite and the ®ltrate is concentrated.
Flash chromatography of the residue (hexane/EtOAc, 50:1)
affords diene 15 as a colorless syrup (39.1 mg, 42%).
[a]2D0114.98 (c1.5, CHCl3); 1H NMR (300 MHz,
CD2Cl2) d 3.80 (2H, m), 4.07 (1H, dd, J5.7, 7.9 Hz),
4.14 (1H, dd, J6.1, 7.7 Hz), 4.27 (1H, d, J11.6 Hz),
4.39 (1H, d, J11.6 Hz), 4.56±4.63 (4H, m), 4.80 (1H, d,
J10.9 Hz), 4.81 (1H, d, J11.0 Hz), 5.25±5.43 (4H, m),
5.94 (1H, ddd, J7.8, 10.4, 17.2 Hz), 6.02 (1H, ddd, J8.0,
10.4, 17.1 Hz), 7.32 (20H, m); 13C NMR (75 MHz, CD2Cl2)
d 70.4, 70.9, 74.4, 75.6, 81.0, 81.7, 82.0, 82.1, 119.3, 119.7,
127.6, 127.7, 127.8, 127.85, 128.0, 128.1, 128.2, 128.3,
128.36, 128.4 (2£) 128.5, 128.6, 136.2, 136.6, 139.0,
139.2, 139.5, 139.6; IR: 3087, 3064, 3030, 2979, 2866,
1673, 1640, 1606, 1585, 1497, 1454, 1422, 1391, 1349,
1305, 1243, 1208, 1089, 1068, 1028, 997, 930, 734, 697,
599; MS (EI) m/z (rel. intensity) 443 ([(M2Bn)1], ,0.1),
181 (10), 147 (5), 91 (100); HRMS C36H38O4 calcd
535.2848, found 535.2840.
2,3,4,5-Tetra-O-benzyl-d-glucitol (13). H2SO4 conc.
(0.2 mL) is added to a cooled solution (08C) of substrate
12 (10.0 g, 9.2 mmol) in MeOH/CH2Cl2 (10:3, 150 mL).
After stirring for 1 h, the reaction is quenched by addition
of NaHCO3 (ca. 5 g) and the resulting slurry is stirred for
30 min. Filtration affords a clear solution which is dried
(Na2SO4) and concentrated. Flash chromatography (hex-
ane/EtOAc, 2:1) provides product 13 as a colorless syrup
1
(4.32 g, 87%). H NMR (300 MHz, CD2Cl2) d 2.09 (1H, t,
J5.5 Hz), 2.22 (1H, t, J5.6 Hz), 3.65 (1H, m), 3.75±3.90
(6H, m), 3.97 (1H, t, J4.7 Hz), 4.43±4.82 (m, 8H), 7.33
(20H, m); 13C NMR (75 MHz, CD2Cl2) d 60.9, 62.0, 72.0,
73.1, 74.5, 75.0, 78.8, 79.7, 80.1, 80.3, 128.0, 128.0, 128.1,
128.3, 128.4, 128.5, 128.7, 128.8, 128.9, 138.7, 138.8 (2x),
138.9; IR: 3442, 3088, 3063, 3030, 3007, 2929, 2876, 1606,
1586, 1496, 1454, 1396, 1352, 1308, 1250, 1209, 1091, 1066,
1028, 913 877, 735, 697, 602; MS (EI) m/z (rel. intensity)
451 ([(M2Bn)1], 2), 345 (8), 253 (6), 181 (29), 91 (100).
2,3,4,5-Tetra-O-benzyl-d-mannitol (19). Deprotection of
compound 18 (8.00 g, 7.36 mmol) was carried out as
described above providing diol 19 as a colorless syrup
1
(3.78 g, 94%). H NMR (300 MHz, CD2Cl2) d 2.14 (2H,
dd, J4.6, 7.6 Hz), 3.77 (4H, m), 3.90±4.00 (4H, m), 4.47
(2H, d, J11.5 Hz), 4.59 (2H, d, J10.7 Hz), 4.63 (2H, d,
J11.1 Hz), 4.77 (2H, d, J11.2 Hz), 7.34 (20H, m); 13C
NMR (75 MHz, CD2Cl2) d 60.3, 71.7, 74.8, 78.8, 80.0,
128.0, 128.1, 128.2, 128.7, 128.8, 138.6; IR: 3448, 3088,
3063, 3030, 2930, 2879, 1605, 1586, 1496, 1454, 1394,
1350, 1326, 1248, 1209, 1095, 1066, 1028, 913, 876, 848,
736, 698, 604; MS (EI) m/z (rel. intensity) 451 ([(M2Bn)1],
1), 181 (23), 91 (100).
(3R,4R,5R,6R)-3,4,5,6-Tetra(benzyloxy)-1,7-octadiene (21).
Diol 19 (205 mg, 0.377 mmol) was processed as described
above affording diene 21 as a colorless solid (94.7 mg,
1
47%). mp66±678C; [a]2D0220.78 (c1.9, CHCl3); H
NMR (300 MHz, CD2Cl2) d 3.82 (2H, d, J6.7 Hz), 4.06
(2H, t, J7.2 Hz), 4.27 (2H, d, J11.5 Hz), 4.45 (2H, d,
J10.9 Hz), 4.61 (2H, d, J11.6 Hz), 4.66 (2H, d,
J10.9 Hz), 5.38 (2H, d, J2.0 Hz), 5.43 (2H, d,
J1.9 Hz), 5.98 (2H, m), 7.28 (20H, m); 13C NMR
(75 MHz, CD2Cl2) d 70.3, 74.9, 80.7, 81.2, 119.9, 127.7,
127.8, 128.2, 128.2, 128.5, 128.7, 136.9, 139.0, 139.3; IR:
3088, 3062, 2978, 2919, 2874, 2846, 2825, 1642, 1606, 1585,
1497, 1452, 1420, 1389, 1342, 1325, 1302, 1281, 1206, 1173,
1142, e1114, 1095, 1069, 1027, 1042, 996, 949, 936, 903,
772, 734, 696, 600, 505; MS (EI) m/z (rel. intensity) 443
([(M2Bn)1], ,0.2), 279 (6), 189 (5), 181 (24), 147 (8),
91 (100). HRMS C36H38O4 calcd 535.2848, found 535.2839.
2,3,4,5-Tetra-O-benzyl-galactitol (25). Substrate 24
(6.31 g, 5.80 mmol) was deprotected as described above
affording product 25 as a colorless solid (2.80 g, 89%).
mp114±1158C; 1H NMR (300 MHz, CD2Cl2) d 2.41
(2H, dt, J1.6, 6.3 Hz), 3.71±3.85 (6H, m), 3.97 (2H, d,
J5.4 Hz), 4.62 and 4.67 (4H, AB, J11.5 Hz), 4.72 (4H,
s), 7.32 (20H, m); 13C NMR (75 MHz, CD2Cl2) d 61.5, 72.9,
74.6, 80.2, 80.4, 127.9, 128.0, 128.2, 128.3, 128.6, 128.7,
138.8, 139.0; IR: 3475, 3087, 3063, 3030, 2926, 2875, 1509,
1497, 1453, 1397, 1334, 1250, 1216, 1109, 1068, 1028,
1004, 751, 697; MS (EI) m/z (rel. intensity) 451
([(M2Bn)1], 0.3), 91 (100).
(3R,4R,5R,6S)-3,4,5,6-Tetra(benzyloxy)-1,7-octadiene (15).
DMSO (540 ml, 7.6 mmol) in CH2Cl2 (2 mL) is added
(3Rp,4Sp,5Rp,6Sp)-3,4,5,6-Tetra(benzyloxy)-1,7-octadiene
(27). Obtained as a colorless solid (41.9 mg, 42%) from diol