max(film)/cm−1 1778, 1713, 1651, 1391 and 1362; H (300 MHz,
4.4 and 6.4), 6.15 (1H, d, J 15.6) and 6.94 (1H, ddd, J 0.9, 6.4 and
15.6); C (75 MHz, CDCl3) 13.1 (q), 55.1 (d), 55.5 (d), 124.5 (d),
144.6 (d) and 170.5 (s).
Compound 13b was obtained from 11b (enantiomer of 11a) in
53% yield (four steps) as white microcrystalline; mp 94–95.5 °C;
[]D24 +72.8 (c, 0.5, CHCl3).
CDCl3) 1.30 (3H, d, J 5.5), 1.51–1.80 (6H, m), 2.97–3.05 (1H, m),
3.32 (1H, dq, J 4.4 and 5.5), 3.51 (1H, ddd, J 0.9, 4.4 and 6.6),
3.55–3.59 (1H, m), 3.78–3.85 (1H, m), 4.32 (1H, dd, J 2.9 and 9.9),
4.34–4.44 (2H, m), 4.45 (1H, dd, J 4.5 and 11.5), 4.64 (1H, d, J 7.8),
5.09 (1H, dd, J 2.2 and 3.8), 6.11 (1H, dd, J 0.9 and 15.7) and 6.80
(1H, dd, J 6.6 and 15.7); C (75 MHz, CDCl3) 12.8 (q), 18.9 (t), 24.9
(t), 29.8 (t), 38.5 (d), 54.9 (d), 55.2 (d), 61.2 (t), 62.6 (t), 67.5 (t),
69.1 (d), 98.0 (d), 124.2 (d), 142.8 (d), 164.8 (s) and 174.2 (s).
(4R,5S,2E)- and (4S,5R,2E)-4,5-Epoxyhexenal, 14a and 14b
To a solution of 12b (bp 85–87 °C/60 mmHg (Kugelrohr),
[]D29 −36.8 (c, 1.0, CHCl3) (48.6 mg, 0.26 mmol) in dry ether
(4 cm3) was added DIBAL-H (1.5 M in toluene, 0.39 cm3,
0.58 mmol) at −78 °C for 15 min. After the reaction mixture was
quenched by addition of water, the precipitate was removed by
filtration through Celite. The filtrate was washed with brine, dried,
and concentrated. The residue was purified by chromatography
(hexane–ether, 8:1) to give 14a (16 mg, 54%) as a colorless oil;
bp 70–75 °C/45 mmHg (Kugelrohr); []D26 −82.5 (c, 1.5, CHCl3);
H (300 MHz, CDCl3) 1.32 (3H, d, J 5.5), 3.41 (1H, dq, J 4.4 and
5.5), 3.63 (1H, ddd, J 0.9, 4.4 and 6.4), 6.40 (1H, ddd, J 0.9, 7.7
and 15.8), 6.80 (1H, dd, J 6.4 and 15.8) and 9.60 (1H, d, J 7.7); C
(75 MHz, CDCl3) 13.1 (q), 55.1 (d), 55.7 (d), 135.3 (d), 150.1 (d)
and 192.2 (d).
Compound 15d. A colorless oil, []D25 −121.0 (c, 1.04, CHCl3);
[Found: (M + H)+, 327.1450. C16H23O7 requires M + H, 327.1445];
H (300 MHz, CDCl3) 1.29 (3H, d, J 5.5), 1.55–1.82 (6H, m),
2.90–2.99 (1H, m), 3.34 (1H, dq, J 4.5 and 5.5), 3.54 (1H, dd, J 4.5
and 6.4), 3.78–3.85 (1H, m), 4.07 (1H, t, J 9.1), 4.34 (1H, dd, J 6.3
and 11.7), 4.42 (1H, d, J 9.4), 4.43 (1H, dd, J 3.9 and 11.7), 4.47
(1H, t, J 9.1), 5.16 (1H, br. s), 6.14 (1H, d, J 15.8) and 6.86 (1H, dd,
J 6.4 and 15.8); C (75 MHz, CDCl3) 13.1 (q), 19.0 (t), 25.2 (t), 30.1
(t), 41.7 (d), 55.1 (d), 55.5 (d), 62.1 (t), 62.6 (t), 67.1 (t), 70.8 (d),
98.0 (d), 124.0 (d), 143.4 (d), 165.0 (s) and 174.5 (s).
(2S,3S,4′R,5′S,2′E)-3-(4′,5′-Epoxy-1′-oxohexenyloxymethyl)-2-
hydroxy-4-butanolide 2a: lactone II
Compound 14b was obtained from tert-butylsorbate in 39% yield
(five steps); ]D23 +83.0 (c, 1.7, CHCl3).
A solution of 15a (15.8 mg, 0.048 mmol) in acetic acid (2 cm3),
THF (1 cm3), and water (0.5 cm3) was stirred at 50 °C for 3 h. After
concentration under reduced pressure, the residue was purified by
chromatography (hexane–ethyl acetate, 1:1) to give 2a (7.4 mg,
63%) as white needles; mp 74–75 °C; []D21 +38.8 (c, 0.1, MeOH);
H (300 MHz, DMSO) 1.23 (3H, d, J 5.5), 2.83–2.91 (1H, m), 3.33
(1H, dq, J 4.4 and 5.5), 3.62 (1H, ddd, J 0.8, 4.4 and 7.1), 4.13 (1H,
dd, J 5.4 and 11.0), 4.19 (1H, dd, J 2.0 and 9.3), 4.27 (1H, dd, J
3.9 and 11.0), 4.33 (1H, dd, J 6.2 and 9.3), 4.56 (1H, dd, J 6.0 and
8.0), 6.12 (1H, dd, J 0.8 and 15.7), 6.13 (1H, d, J 5.9, OH) and 6.67
(1H, dd, J 7.1 and 15.7); H (300 MHz, CDCl3) 1.30 (3H, d, J 5.5),
2.95–3.03 (m, 1H), 2.99 (1H, br.s, OH), 3.33 (1H, dq, J 4.6 and 5.5),
3.51 (1H, ddd, J 0.9, 4.4 and 6.6), 4.33 (1H, dd, J 5.5 and 11.7),
4.35–4.43 (2H, m), 4.49 (1H, dd, J 3.8 and 11.7), 4.59 (1H, d, J 8.1),
6.11 (1H, dd, J 0.5 and 15.8) and 6.81 (1H, dd, J 6.4 and 15.8); C
(75 MHz, CDCl3) 13.1 (q), 38.9 (d), 55.2 (d), 55.5 (d), 61.0 (t), 67.6
(t), 67.8 (d), 124.2 (d), 143.5 (d), 165.2 (s) and 176.5 (s).
(2S,3S,4′R,5′S,2′E)- and (2S,3R,4′R,5′S,2′E)-3-(4′,5′-Epoxy-1′-
oxohexenyloxymethyl)-2-tetrahydropyranyloxy-4-butanolide,
15a and 15b
To a solution of the alcohol 8 (mixture of 8a and 8b) (121.5 mg,
0.56 mmol) and the acid 13a (60 mg, 0.47 mmol) in dry dichloro-
methane (10 cm3) were added DMAP (68.7 mg, 0.56 mmol)
and DCC (116.0 mg, 0.56 mmol) at 0 °C, and the mixture was
stirred at room temperature for 24 h. After concentration under
reduced pressure, the residue was purified by chromatography
(hexane–ethyl acetate, 2:1) to give 15a (117.5 mg, 77%) and 15b
(16.8 mg, 11%).
Compound 15a. A colorless oil, []D25 −66.0 (c, 0.89, CHCl3);
[Found: (M + H)+, 327.1448. C16H23O7 requires M + H, 327.1445];
H (300 MHz, CDCl3) 1.30 (3H, d, J 5.3), 1.51–1.81 (6H, m),
2.94–2.96 (1H, m), 3.32 (1H, dq, J 4.4 and 5.3), 3.51 (1H, dd, J 4.4
and 6.4), 3.50–3.55 (1H, m), 3.75–3.78 (1H, m), 4.29–4.40 (3H, m),
4.48 (1H, dd, J 4.4 and 11.6), 4.63 (1H, d, J 7.7), 5.10 (1H, dd, J 2.3
and 4.3), 6.08 (1H, d, J 15.6) and 6.82 (1H, dd, J 6.4 and 15.6); C
(75 MHz, CDCl3) 13.0 (q), 19.1 (t), 25.1 (t), 30.0 (t), 38.8 (d), 55.2
(d), 55.4 (d), 61.3 (t), 62.9 (t), 67.7 (t), 69.3 (d), 98.2 (d), 124.4 (d),
143.1 (d), 165.1 (s) and 174.4 (s).
(2S,3R,4′R,5′S,2′E)-3-(4′,5′-Epoxy-1′-oxohexenyloxymethyl)-
2-hydroxy-4-butanolide 2b
In the same manner as described above, 15b was converted to 2b in
69% yield as a colorless oil; []D21 −78.5 (c, 0.11, MeOH); [Found:
M+, 242.0779. C11H14O6 requires M, 242.0790]; H (300 MHz,
CDCl3) 1.30 (3H, d, J 5.3), 2.83–2.96 (1H, m), 3.35 (1H, dq, J 4.5
and 5.3), 3.55 (1H, ddd, J 0.9, 4.5 and 6.3), 4.00 (1H, br.s, OH), 4.07
(1H, dd, J 9.7 and 9.9), 4.37 (1H, d, J 9.8), 4.36 (1H, dd, J 3.8 and
10.2), 4.45 (1H, dd, J 4.3 and 11.6), 4.47 (1H, dd, J 7.9 and 9.9),
6.15 (1H, dd, J 0.9 and 15.7) and 6.87 (1H, dd, J 6.3 and 15.7); C
(75 MHz, CDCl3) 13.0 (q), 43.1 (d), 55.1 (d), 55.5 (d), 61.9 (t), 66.9
(d), 68.8 (t), 124.0 (d), 143.4 (d), 165.2 (s) and 176.7 (s).
Compound 15b. A colorless oil, []D25 −170.5 (c, 1.10, CHCl3);
[Found: (M + H)+, 327.1459. C16H23O7 requires M + H, 327.1445];
max(film)/cm−1 1790, 1724, 1655 and 1391; H (300 MHz, CDCl3)
1.30 (3H, d, J 5.5), 1.52–1.83 (6H, m), 2.87–2.99 (1H, m), 3.34 (1H,
dq, J 4.4 and 5.5), 3.53 (1H, ddd, J 1.1, 4.4 and 6.2), 3.56–3.58 (1H,
m), 3.77–3.85 (1H, m), 4.08 (1H, t, J 9.3), 4.33 (1H, dd, J 6.4 and
11.7), 4.43 (1H, d, J 9.3), 4.44 (1H, dd, J 4.0 and 11.7), 4.48 (1H,
dd, J 6.3 and 9.3), 5.16 (1H, dd, J 2.3 and 3.5), 6.14 (1H, dd, J 1.1
and 15.8) and 6.86 (1H, dd, J 6.4 and 15.8); C (75 MHz, CDCl3)
13.0 (q), 18.9 (t), 25.1 (t), 30.0 (t), 41.6 (d), 55.0 (d), 55.4 (d), 62.0
(t), 62.5 (t), 67.0 (t), 70.7 (d), 97.9 (d), 124.0 (d), 143.3 (d), 164.9
(s) and 174.5 (s).
(2S,3S,4′S,5′R,2′E)-3-(4′,5′-Epoxy-1′-oxohexenyloxymethyl)-2-
hydroxy-4-butanolide 2c
In the same manner as described above, 15c was converted to 2c in
58% yield as white microcrystalline; mp 94–95 °C; []D20 +121.0
(c, 0.11, MeOH); [Found: M+, 242.0785. C11H14O6 requires M,
242.0790]; H (300 MHz, DMSO) 1.23 (3H, d, J 5.5), 2.82–2.91
(1H, m), 3.33 (1H, dq, J 4.4 and 5.5), 3.61 (1H, dd, J 4.4 and 7.1),
4.15 (1H, dd, J 5.3 and 11.2), 4.20 (1H, dd, J 2.0 and 9.3), 4.25
(1H, dd, J 3.8 and 11.2), 4.34 (1H, dd, J 6.2 and 9.3), 4.56 (1H,
dd, J 5.7 and 7.9), 6.12 (1H, d, J 5.7, OH), 6.13 (1H, d, J 15.6)
and 6.66 (1H, dd, J 7.1 and 15.6); H (300 MHz, CDCl3) 1.31 (3H,
d, J 5.5), 2.95–3.03 (1H, m), 3.18 (1H, br s, OH), 3.33 (1H, dq, J
4.6 and 5.3), 3.51 (1H, ddd, J 0.9, 4.4 and 6.5), 4.34 (1H, dd, J 5.3
and 11.4), 4.34–4.42 (2H, m), 4.46 (1H, dd, J 3.8 and 11.4), 4.60
(1H, d, J 8.0), 6.11 (1H, dd, J 0.9 and 15.7) and 6.80 (1H, dd, J 6.5
(2S,3S,4′S,5′R,2′E)- and (2S,3R,4′S,5′R,2′E)-3-(4′,5′-Epoxy-1′-
oxohexenyloxymethyl)-2-tetrahydropyranyloxy-4-butanolide,
15c and 15d
In the same manner as described above, the reaction of 8 with 13b
gave 15c (128 mg, 54%) and 15d (55.6 mg, 24%).
Compound 15c. A colorless oil, []D26 −4.3 (c, 1.10, CHCl3);
[Found: (M + H)+, 327.1465. C16H23O7 requires M + H, 327.1445];
O r g . B i o m o l . C h e m . , 2 0 0 4 , 2 , 2 7 7 7 – 2 7 8 5
2 7 8 3