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J. H. Kim et al. / Tetrahedron 59 (2003) 7501–7507
ether, 5:1); [a]2D7¼266.7 (c¼0.12, EtOH); 1H NMR
(300 MHz, CDCl3) d 7.58–7.16 (m, 5H, C6H5), 4.99 (m,
1H, H-40), 3.69 (d, J¼11.7 Hz, 1H, H-2), 2.69–2.61 (m,
1H), 2.30–2.22 (m, 1H) 2.04–1.86 (m, 4H), 1.78–1.38
(m, 4H), 1.65 (s, 3H, 50-CH3), 1.55 (s, 3H, 50-CH3), 1.33 (s,
3H, 10-CH3), 1.16 (d, J¼6.3 Hz, 3H, 3-CH3), 0.10 (s, 9H,
Si(CH3)3); 13C NMR (75 MHz, CDCl3) d 206.7, 134.2,
131.1, 130.0, 128.9, 127.2, 124.5, 64.9, 58.1, 43.7, 40.6,
poured into CH2Cl2 and water. The organic layer was
separated and the aqueous layer was extracted with CH2Cl2.
The combined organic solution was washed with brine,
dried over MgSO4 and concentrated in vacuo. The residue
was purified by column chromatography (SiO2, hexane/
diethyl ether, 2.5:1) to give (þ)-hernandulcin (111 mg,
100%). TLC Rf¼0.47 (hexane/diethyl ether, 1:1); [a]2D6¼
þ110.58 (c¼0.11, EtOH), lit. [a]2D5¼þ1098 (c¼0.11,
EtOH),1 [a]2D0¼þ1228 (c¼0.111, EtOH),8a [a]2D2¼þ1268
(c¼0.113, EtOH);8b 1H NMR (300 MHz, CDCl3) d 5.88 (s,
1H, H-2), 5.27 (s, 1H, OH), 5.12 (m, 1H, H-40), 2.46–2.31
(m, 3H), 2.30–1.98 (m, 3H), 1.97 (s, 3H, 3-CH3), 1.76–1.64
(m, 1H), 1.69 (d, J¼1.2 Hz, 3H, 50-CH3), 1.63 (s, 3H, 50-
35.3, 28.1, 25.7, 24.4, 22.7, 22.3, 17.6, 2.6; IR (neat, cm21
2956, 1713, 1249, 1032, 839, 740.
)
4.1.10. (6S,10S)-6-(10,50-Dimethyl-10-trimethylsilyloxy-40-
hexenyl)-3-methyl-2-cyclohexenone (8a). To a solution of
7a (410 mg, 0.88 mmol) in 9 mL of CH2Cl2 containing
0.18 mL of pyridine was gradually added 0.3 g of 30%
H2O2 and 0.3 mL of water at 08C. The mixture was stirred
vigorously for 15 min at room temperature. It was then
poured into CH2Cl2 (80 mL) and 20% NaHCO3 solution
(40 mL). The organic layer was separated and the aqueous
layer was extracted with CH2Cl2. The combined organic
phase was washed with brine, dried over MgSO4 and
concentrated in vacuo. The residue was purified by column
chromatography (SiO2, hexane/diethyl ether, 5:1) to give 8a
(223 mg, 82%). TLC Rf¼0.32 (hexane/diethyl ether, 5:1);
[a]2D7¼þ9.7 (c¼0.14, EtOH); 1H NMR (300 MHz, C6D6) d
5.84 (s, 1H, H-2), 5.30 (m, 1H, H-40), 2.40–1.84 (m, 6H),
1.79–1.60 (m, 2H), 1.67 (s, 6H, 50-CH3), 1.57 (s, 3H, 3-
CH3), 1.39 (s, 3H, 10-CH3), 0.92–0.76 (m, 1H), 0.15 (s, 9H,
Si(CH3)3); 13C NMR (75 MHz, C6D6) d 198.3, 158.9,
131.0, 128.6, 125.5, 78.1, 55.3, 40.0, 31.0, 27.6, 25.8, 24.4,
23.7, 23.3, 17.7, 2.7; IR (neat, cm21) 2962, 1668, 1250,
1075, 839, 753; HRMS (FABþ) calcd for C18H33O2Si
309.2250, found 309.2251.
CH3), 1.44–1.51 (m, 2H, 20-CH2), 1.18 (s, 3H, 10-CH3); 13
C
NMR (75 MHz, CDCl3) d 204.1, 163.5, 131.5, 127.5, 124.5,
73.9, 52.1, 40.2, 31.3, 25.7, 25.1, 24.1, 23.6, 21.5, 17.6; IR
(neat, cm21) 3454, 2970, 1649, 1381, 1215, 1124, 585;
HRMS (FABþ) calcd for C15H25O2 2371855, found
237.1856.
4.1.13. (6S,10R)-6-(10-Hydroxy-10,50-dimethyl-40-
hexenyl)-3-methyl-2-cyclohexenone ((1)-epihernandul-
cin). To a mixture of acetonitrile (3 mL) and 40% aqueous
HF (0.15 mL) was added 8b (100 mg, 0.32 mmol). The
mixture was stirred for 15 min at room temperature. It was
then poured into CH2Cl2 and water. The organic layer was
separated and the aqueous layer was extracted with CH2Cl2.
The combined organic solution was washed with brine,
dried over MgSO4 and concentrated in vacuo. The residue
was purified by column chromatography (SiO2, hexane/
diethyl ether, 2.5:1) to give (þ)-epihernandulcin (74 mg,
97%). TLC Rf¼0.25 (hexane/diethyl ether, 1:1); [a]2D7¼
þ141.08 (c¼0.12, EtOH), lit. [a]1D5¼þ1418 (c¼0.111,
EtOH);8b 1H NMR (300 MHz, CDCl3) d 5.86 (s, 1H, H-2),
5.14–5.00 (m, 2H), 2.40–2.31 (m, 3H), 2.29–2.13 (m, 1H),
2.10–2.00 (m, 2H), 1.96 (s, 3H, 3-CH3), 1.84–1.68 (m, 1H),
1.66 (d, J¼1.2 Hz, 3H, 50-CH3), 1.61 (s, 3H, 50-CH3), 1.55
(dd, J¼12, 4.8 Hz, 1H), 1.39 (ddd, J¼13.8, 12, 5.4 Hz, 1H),
1.20 (s, 3H, 10-CH3); 13C NMR (75 MHz, CDCl3) d 203.5,
163.4, 131.4, 127.5, 124.7, 74.4, 55.4, 37.0, 31.5, 25.7, 25.4,
25.0, 24.1, 22.1, 17.6; IR (neat, cm21) 3444, 2972, 1644,
1381, 1265, 1216, 739; HRMS (FABþ) calcd for C15H25O2
2371855, found 237.1855.
4.1.11. (6S,10R)-6-(10,50-Dimethyl-10-trimethylsilyloxy-40-
hexenyl)-3-methyl-2-cyclohexenone (8b). To a solution of
7b (100 mg, 0.21 mmol) in 3 mL of CH2Cl2 containing
0.06 mL of pyridine was gradually added 0.1 g of 30%
H2O2 and 0.1 mL of water at 08C. The mixture was stirred
vigorously for 15 min at room temperature. It was then
poured into CH2Cl2 (20 mL) and 20% NaHCO3 solution
(10 mL). The organic layer was separated and the aqueous
layer was extracted with CH2Cl2. The combined organic
phase was washed with brine, dried over MgSO4 and
concentrated in vacuo. The residue was purified by column
chromatography (SiO2, hexane/diethyl ether, 5:1) to give 8b
(69 mg, 84%). TLC Rf¼0.26 (hexane/diethyl ether, 5:1);
References
1
[a]2D7¼212.7 (c¼0.11, EtOH); H NMR (300 MHz, C6D6)
d 5.84 (s, 1H, H-2), 5.30 (m, 1H, H-40), 2.49–2.37 (m, 2H),
2.24–2.03 (m, 3H), 1.97–1.70 (m, 3H), 1.69 (s, 3H, 50-
CH3), 1.65 (s, 3H, 50-CH3), 1.39 (s, 3H, 3-CH3), 1.38 (s, 3H,
10-CH3), 0.92–0.76 (m, 1H), 0.15 (s, 9H, Si(CH3)3); 13C
NMR (75 MHz, C6D6) d 198.6, 159.2, 131.1, 125.2,
78.0, 52.6, 43.0, 31.0, 25.8, 25.0, 24.4, 23.3, 23.2, 17.7,
2.7; IR (neat, cm21) 2963, 1658, 1265, 1040, 840, 740;
HRMS (FABþ) calcd for C18H33O2Si 309.2250, found
309.2253.
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4.1.12. (6S,10S)-6-(10-Hydroxy-10,50-dimethyl-40-
hexenyl)-3-methyl-2-cyclohexenone ((1)-hernandulcin).
To a mixture of acetonitrile (4 mL) and 40% aqueous HF
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was stirred for 15 min at room temperature. It was then
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