1988
H. Hagiwara et al. / Tetrahedron 60 (2004) 1983–1989
3.1.9. 4-[(1S,6S)-6-(3-Iodopropanoyl)-2,2,6-trimethyl-
cyclohexyl]butan-2-one (22). To a stirred solution of the
iodide 18b (68 mg, 0.19 mmol) in DCM (3.0 mL) was
passed O3/O2 at 278 8C for 2 h. After addition of
dimethylsulfide (2.0 mL), the resulting solution was stirred
for 1 h at 278 8C and allowed to stand overnight until
ambient temperature. Evaporation of the solvent followed
by column chromatography (eluent: ethyl acetate–n-
hexane¼1:1) and subsequent MPLC (eluent: ethyl acetate–
n-hexane¼1:3) afforded seco-iodide 22 (29 mg, 41%) as a
colorless oil; [a]2D0 þ13.50 (c 0.51); IR 2932, 1717, 1462,
1356, 1327, 1267, 1165 cm21; 1H NMR (200 MHz) d 0.92
(s, 3H), 0.93 (s, 3H), 1.10–1.79 (m, 9H), 1.22 (s, 3H), 2.10
(s, 3H), 2.32–2.67 (m, 2H), 3.07–3.18 (m, 2H), 3.29 (t, 2H,
J¼6.4 Hz); 13C NMR (67.5 MHz) d22.9, 17.1, 18.1, 22.4,
22.6, 30.1, 33.5, 34.4, 37.2, 41.2, 41.6, 45.8, 47.4, 52.9,
208.8, 213.8; MS (EI) m/z 378 (Mþ, 3.8), 195 (31), 177
(100), 149 (38). exact mass calcd for C16H27O2I, 378.1056,
found 378.1060.
acetate 21 (54 mg, 0.173 mmol) in benzene (1.7 mL) was
added 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) (31 mL,
0.208 mmol) and the solution was stirred for 1 h at room
temperature under nitrogen atmosphere. To the solution
were added g-lactone 7c (55 mg, 0.266 mmol) and DBU
(39 mL, 0.260 mmol) and the resulting solution was stirred
for 1 h. The solution was then heated at 60 8C for 2 h. The
reaction was quenched by addition of 1 M HCl and
extracted with ethyl acetate four times. The combined
organic layer was washed with water and brine and dried
over anhydrous Na2SO4. Evaporation of the solvent
followed by column chromatography (eluent: ethyl acetate–
n-hexane¼1:2) and subsequent MPLC (eluent: ethyl
acetate–n-hexane¼2:1) furnished chapecoderin A (1)
(23 mg, 39%) and chapecoderin B (2) (10 mg, 18%) as
amorphous solids.
Chapecoderin A 1 had [a]2D3 þ6.0 (c 0.86) {lit. [a]2D3þ5.5
(c 0.86)}; IR 2934, 1765, 1717, 1699, 1072 cm21; 1H NMR
(500 MHz) d 0.91 (s, 3H), 0.92 (s, 3H), 1.16–1.22 (m, 2H),
1.22 (s, 3H), 1.31–1.38 (m, 1H), 1.40–1.43 (m, 1H), 1.46–
1.52 (m, 2H), 1.53–1.63 (m, 2H), 1.73 (t, 1H, J¼4.9 Hz),
2.10 (s, 3H), 2.44 (t, 2H, J¼8.2 Hz), 2.56 (td, 2H, J¼7.0,
1.4 Hz), 2.76 (dt, J¼18.2, 6.9 Hz), 2.87 (dt, J¼18.2,
7.3 Hz), 4.76 (dd, 2H, J¼2.0, 1.5 Hz), 7.17 (t, J¼1.5 Hz);
13C NMR (125 MHz) d 17.1 (q), 18.1 (t), 20.2 (t), 22.2 (t),
22.5 (q), 29.8 (q), 33.4 (q), 34.3 (q), 34.9 (t), 37.1 (t), 41.1
(t), 45.5 (t), 47.6 (d), 53.5 (s), 70.1 (t), 132.9 (s), 145.7 (d),
174.1 (s), 208.9 (s), 215.2 (s).
3.1.10. 2-((1S,6S)-1,3,7,7-Tetramethylbicyclo[4.4.0]dec-
2-en-2-yl)ethyl acetate (18c). To a solution of the alcohol
14 (28 mg, 0.12 mmol) in dry pyridine (2.0 mL) was added
DMAP (1.4 mg, 0.012 mmol) and acetic anhydride (35 mL,
0.35 mmol) under nitrogen atmosphere and the solution was
stirred at room temperature for 1 h. The reaction was
quenched by addition of water and product was extracted
with ethyl acetate twice. The combined organic layer was
washed with brine and dried over anhydrous Na2SO4.
Evaporation of the solvent followed by column chromato-
graphy (eluent: ethyl acetate–n-hexane¼1:1) and sub-
sequent MPLC (eluent: ethyl acetate–n-hexane¼1:2) gave
acetate 18c (29 mg, 88%) as a colorless oil; [a]2D0 þ32.6 (c
Peaks at 30.0 (C-7) and 19.5 (C-20) ppm in original paper1
were mistyped and should be corrected to 45.8 and
17.3 ppm, respectively, according to private communication
from Professor Shigemori.
1
1.02); IR 2965, 2940, 1742, 1237, 1030 cm21; H NMR
(200 MHz) d 0.83 (s, 3H), 0.88 (s, 3H), 0.94 (s, 3H), 1.62 (s,
3H), 0.95–1.74 (m, 9H), 1.80–2.14 (m, 2H), 2.05 (s, 3H),
2.15–2.48 (m, 2H), 4.00 (t, 2H, J¼7.9 Hz); 13C NMR
(50 MHz) d 18.9 (t), 19.0 (t), 19.9 (q), 20.0 (q), 21.6 (q),
31.4 (t), 33.3 (q), 33.3 (s), 33.6 (t), 37.1 (t), 38.6 (s), 41.7 (t),
51.6 (d), 62.6 (t), 128.5 (s), 136.1 (s). Anal. calcd for
C18H30O2: C, 77.7; H, 10.9. Found: C, 77.5; H, 11.2.
Chapecodeirn B (2) had [a]2D3 211.9 (c 0.31) {lit. [a]2D3
24.6 (c 0.38)}; 1H NMR (500 MHz) d 0.72 (s, 3H), 0.82 (s,
3H), 0.84 (s, 3H), 1.12 (m, 1H), 1.34 (m, 2H), 1.40 (m, 1H),
1.52 (m, 1H), 1.54 (m, 1H), 1.75 (m, 1H), 1.78 (m, 1H), 1.80
(s, 3H), 2.04 (dt, 1H, J¼5.0, 12.4 Hz), 2.27 (dd, 1H, J¼8.1,
12.7 Hz), 2.29 (m, 1H), 2.47 (td like), 2.56 (dd, 1H, J¼5.0,
12.1 Hz), 3.77 (s, 2H), 5.90 (s, 1H); 13C NMR (125 MHz) d
16.1, 19.8, 21.0, 21.4, 27.1, 31.1, 31.2, 33.2, 33.6, 35.6,
41.5, 49.4, 51.4, 53.7, 69.4, 84.7, 134.4, 143.6, 173.8, 215.5.
Inconsistency of value of optical rotations may arise from
different purity of synthetic chapecoderin B (2).
3.1.11. 3-[(10S,20S)-10,30,30-Trimethyl-20-(300-oxobutyl)-
cyclohexyl]-3-oxopropyl acetate (21). To a solution of
the acetate 18c (26 mg, 0.095 mmol) in anhydrous methanol
(10 mL) was passed into O3/O2 at 220 8C for 35 min. After
flushing the solution with N2, dimethylsulfide (2.0 mL) was
added and the resulting solution was stirred at 220 8C for
2 h. Evaporation of the solvent followed by column
chromatography (eluent: ethyl acetate–n-hexane¼1:2) and
subsequent MPLC (eluent: ethyl acetate–n-hexane¼7:8)
afforded seco-acetate 21 (22 mg, 75%) as a colorless oil;
[a]2D0 256.7 (c 1.00); IR 2953, 2872, 1745, 1719,
3.1.13. Chapecoderin C (3). To a stirred solution of
chapecoderin B (2) (21 mg, 0.06 mmol) and DMAP
(2.3 mg, 0.018 mmol) in pyridine (0.6 mL) was added
SOCl2 (7 mL, 0.9 mmol) at 0 8C under nitrogen atmosphere
and the resulting solution was stirred for 1.5 h at 0 8C. The
reaction was quenched by addition of water and extracted
with ethyl acetate twice. The combined organic layer was
washed with water and brine and dried over anhydrous
Na2SO4. Evaporation of the solvent followed by MPLC
(eluent: ethyl acetate–n-hexane¼2:1) furnished chapeco-
derin C (3) (10 mg, 52%) as an amorphous solid; [a]D23
þ11.6 (c 1.10) {lit. [a]2D3 þ5.7 (c 1.10)}; 1H NMR
(500 MHz) d 0.78 (s), 0.87 (s), 0.92 (s), 1.05 (td, J¼13.1,
3.8 Hz), 1.24 (td, J¼13.1, 3.8 Hz), 1.34 (dd, J¼6.6,
11.7 Hz), 1.38 (td, J¼3.8, 13.1 Hz), 1.48 (m), 1.57 (tq,
J¼3.8, 13.1 Hz), 1.70 (td, J¼3.8,13.1 Hz), 1.94 (s), 2.10
1
1238 cm21; H NMR (200 MHz) d 0.92 (s, 3H), 0.93 (s,
3H), 1.22 (s, 3H), 1.28–1.75 (m, 9H), 2.02 (s, 3H), 2.10 (s,
3H), 2.46 (m, 2H), 2.82 (td, 2H, J¼6.5, 4.1 Hz), 4.00 (t, 2H,
J¼7.9 Hz); 13C NMR (50 MHz) d 17.1 (q), 18.6 (t), 20.9 (q),
22.2 (t), 22.5 (q), 29.9 (q), 33.3 (q), 34.3 (s), 36.7 (t), 37.2
(t), 41.0 (t), 45.5 (t), 47.3 (d), 52.9 (s), 59.9 (t), 170.9 (s),
208.9 (s), 213.8 (s). Anal. calcd for C18H30O4: C, 69.6; H,
9.7. Found: C, 69.6; H, 10.0.
3.1.12. Chapecoderin A (1). To a stirred solution of the