Md. M. Ahmed, G. A. O’Doherty / Carbohydrate Research 341 (2006) 1505–1521
1513
2933, 2878, 1719, 1654, 1463, 1393, 1369, 1316, 1270,
14:1 dr) in 86% yield from 11b (50 mg, 0.29 mmol) as
a viscous oil. Major isomer: Rf (100% EtOAc/hex-
1
1211, 1171, 1113, 1044, 978 cmꢂ1; H NMR (CDCl3,
25
600 MHz): d 6.95 (ddd, J = 15.6, 7.8, 7.2 Hz, 1H), 5.87
(dd, J = 15.6, 1.2 Hz, 1H), 4.15 (q, J = 7.2 Hz, 2H),
3.65 (dddd, J = 7.2, 6.6, 5.4, 4.8 Hz, 1H), 2.37 (ddd,
J = 15, 6.6, 4.8 Hz, 1H), 2.30 (ddd, J = 15, 8.4, 7.8 Hz,
1H), 2.07 (br s, 1H), 1.52 (dqd, J = 7.2, 7.2, 4.8 Hz,
1H), 1.46 (dqd, J = 7.8, 7.2, 6.6 Hz, 1H), 1.25 (t,
J = 7.2 Hz, 3H), 0.93 (t, J = 7.2 Hz, 3H); 13C NMR
(CDCl3, 150 MHz): d 166.3, 145.2, 123.8, 71.8, 60.2,
39.6, 29.9, 14.2, 9.8; CIMS calculated for [C9H16O3+
Na]+: 195.0992. Found: 195.1006.
ane) = 0.29; ½aꢁD ꢂ4.1 (c 0.8, CH2Cl2); IR (thin film):
3459, 2971, 2931, 1738, 1507, 1448, 1374, 1301, 1261,
1
1214, 1140, 1079, 1028, 939 cmꢂ1; H NMR (CDCl3,
600 MHz): d 4.30 (q, J = 7.2 Hz, 2H), 4.21–4.17 (m,
1H), 4.06 (dd, J = 6, 1.8 Hz, 1H), 3.87–3.83 (m, 1H),
3.28 (br s, 1H), 3.15 (d, J = 6 Hz, 1H), 2.52 (br s, 1H),
1.81–1.75 (m, 2H), 1.72 (ddd, J = 14.4, 3, 3 Hz, 1H),
1.54 (ddd, J = 14.4, 7.2, 6.6 Hz, 1H), 1.32 (t,
J = 7.2 Hz, 3H), 0.95 (t, J = 7.2 Hz, 3H); 13C NMR
(CDCl3, 150 MHz): d 172.9, 73.7, 73.4, 72.9, 62.0,
39.0, 30.9, 14.1, 9.6; CIMS calculated for [C9H18O5+
Na]+: 229.1046. Found: 229.1052.
4.14. (2S,3R,5S)-Ethyl 2,3,5-trihydroxyheptanoate (16b)
Following the same procedure as described for com-
pound 16a (see Section 4.7) the 16b was produced
(71 mg, 10:1 dr) in 80% yield from 11b (75 mg,
0.44 mmol) as a viscous oil. Major isomer: Rf (100%
4.17. (3R,4S,6S)-6-Ethyl-tetrahydro-3,4-dihydroxypyran-
2-one (22b)
Following the same procedure as described for com-
pound 22a (see Section 4.10), 22b was produced
(30 mg, 0.20 mmol) in 80% yield from 17b (50 mg,
0.26 mmol) as a viscous oil. Rf (50% EtOAc/hex-
25
EtOAc) = 0.29; ½aꢁD 1.3 (c 0.8, CH2Cl2); IR (thin film):
3485, 2972, 2959, 2936, 1735, 1507, 1465, 1443, 1370,
1287, 1219, 1180, 1108, 1036, 981 cmꢂ1 1H NMR
;
25
(CDCl3, 600 MHz): d 4.30 (q, J = 7.8 Hz, 1H), 4.28 (q,
J = 7.8 Hz, 1H), 4.23 (m, 1H), 4.09 (dd, J = 6, 1.8 Hz,
1H), 3.88 (m, 1H), 3.23 (d, J = 3.6 Hz, 1H), 2.69 (d,
J = 7.8 Hz, 1H), 2.08 (d, J = 4.8 Hz, 1H), 1.84–1.67
(m, 2H), 1.57–1.51 (m, 2H), 1.31 (t, J = 7.8 Hz, 3H),
0.96 (t, J = 7.2 Hz, 3H); 13C NMR (CDCl3, 150 MHz):
d 173.2, 73.8, 70.3, 69.7, 62.1, 39.6, 30.4, 14.1, 9.9; CIMS
calculated for [C9H18O5+Na]+: 229.1046. Found:
229.1049.
ane) = 0.22; ½aꢁD ꢂ5.8 (c 0.66, CH2Cl2); IR (thin film):
3468, 2972, 2959, 2936, 1745, 1507, 1465, 1443, 1370,
1287, 1219, 1180, 1108, 1036, 981 cmꢂ1 1H NMR
;
(CDCl3, 600 MHz): d 4.50 (dddd, J = 10.8, 7.2, 5.4,
3 Hz, 1H), 4.31 (d, J = 7.8 Hz, 1H), 3.99 (ddd, J = 8.4,
7.8, 3.6 Hz, 1H), 3.31 (br s, 1H), 2.62 (br s, 1H), 2.13
(ddd, J = 15, 10.8, 8.4 Hz, 1H), 1.96 (ddd, J = 15, 3.6,
3.6 Hz, 1H), 1.76 (ddq, J = 14.4, 7.8, 7.2 Hz, 1H), 1.65
(dqd, J = 14.4, 7.2, 6.6 Hz, 1H), 1.02 (t, J = 7.2 Hz,
3H); 13C NMR (CDCl3, 150 MHz): d 173.8, 76.9, 73.0,
69.7, 35.9, 27.9, 9.4; CIMS calculated for [C7H12O4+
Na]+: 183.0627. Found: 183.0624.
4.15. (3S,4R,6S)-6-Ethyl-tetrahydro-3,4-dihydroxypyran-
2-one (21b)
Following the same procedure as described for com-
pound 21a (see Section 4.8), 21b was produced (30 mg,
0.20 mmol) in 80% yield from 16b (50 mg, 0.26 mmol)
4.18. (2S,3R,5S)-Ethyl 2,3,5-trihydroxyhexanoate (11c)
25
as a viscous oil. Rf (100% EtOAc) = 0.21; ½aꢁD ꢂ21.2
Following the same procedure as described for com-
pound 11a (see Section 4.5), 11c was produced (0.22 g,
9:1 dr) in 81% yield from 10c (0.23 g, 1.4 mmol) as a vis-
cous oil. Major isomer: Rf (50% EtOAc/hexane) = 0.16;
(c 0.5, CH2Cl2); IR (thin film): 3468, 2972, 2959, 2936,
1745, 1507, 1465, 1443, 1370, 1287, 1219, 1180, 1108,
1
1036, 981 cmꢂ1; H NMR (CDCl3, 600 MHz): d 4.27
25
(dddd, J = 10.2, 7.8, 6.6, 3 Hz, 1H), 4.04 (ddd,
J = 11.4, 10.2, 3.6 Hz, 1H), 3.97 (d, J = 10.2 Hz, 1H),
3.35 (br s, 1H), 2.72 (br s, 1H), 2.26 (ddd, J = 13.8,
7.2, 3.6 Hz, 1H), 1.82 (ddd, J = 13.2, 11.4, 1.8 Hz,
1H), 1.81–1.68 (m, 2H), 1.01 (t, J = 7.2 Hz, 3H); 13C
NMR (CDCl3, 150 MHz): d 173.0, 79.6, 74.3, 69.2,
35.2, 28.7, 9.1; CIMS calculated for [C7H11O4+Na2]+:
205.0447. Found: 205.0445.
½aꢁD ꢂ6 (c 0.4, CH2Cl2); IR (thin film): 3485, 2972, 2959,
2936, 1735, 1507, 1465, 1443, 1370, 1287, 1219, 1180,
1
1108, 1036, 981 cmꢂ1; H NMR (CDCl3, 600 MHz): d
4.29 (dd, J = 4.2, 1.8 Hz, 1H), 4.27 (q, J = 7.2 Hz,
1H), 4.22 (ddd, J = 10.2, 6, 3.6 Hz, 1H), 4.16 (dqd,
J = 9.6, 6, 2.4 Hz, 1H), 4.08 (dd, J = 6, 2.4 Hz, 1H),
3.29 (d, J = 6 Hz, 1H), 2.82 (d, J = 4.2 Hz, 1H), 2.80
(d, J = 6.6 Hz, 1H), 1.88 (ddd, J = 15, 9.6, 3 Hz, 1H),
1.62 (ddd, J = 15, 8.4, 3.6 Hz, 1H), 1.31 (t, J = 7.2 Hz,
3H), 1.27 (d, J = 6 Hz, 3H); 13C NMR (CDCl3,
150 MHz): d 173.2, 73.8, 69.7, 65.1, 62.1, 41.5, 23.6,
14.1; CIMS calculated for [C8H16O5+Na]+: 215.0889.
Found: 215.0892.
4.16. (2R,3S,5S)-Ethyl 2,3,5-trihydroxyheptanoate (17b)
Following the same procedure as described for com-
pound 17a (see Section 4.9), 17b was produced (51 mg,