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H. M. L. Davies, X. Dai / Tetrahedron 62 (2006) 10477–10484
another 2 h. After cooling down, the reaction mixture was
quenched with saturated aqueous NH4Cl and extracted
with ether. The organic layer was washed with brine and
dried over Na2SO4, and concentrated in vacuo. Purification
by column chromatography on silica gel (eluting with 2%
ether/pentane) gave the title compound (86 mg, 80%).
[a]2D5 6.4 (c 1.0, CHCl3); 1H NMR (500 MHz, CDCl3)
d 5.13 (t, J¼7.0 Hz, 1H), 3.85 (s, 3H), 3.81 (s, 3H), 3.65
(s, 3H), 3.15 (m, 1H), 2.88 (m, 1H), 2.18 (s, 3H), 1.91–
2.07 (m, 4H), 1.79 (m, 2H), 1.69 (s, 3H), 1.60 (s, 3H),
1.45 (m, 1H), 1.22–1.38 (m, 2H), 1.14 (d, J¼7.5 Hz, 3H),
0.72 (d, J¼7.0 Hz, 3H); 13C NMR (75 MHz, CDCl3)
d 153.0, 149.5, 147.0, 134.9, 130.8, 128.7, 125.3, 122.2,
60.5, 60.1, 59.9, 37.5, 35.74, 35.71, 27.0, 26.7, 26.4, 25.7,
23.2, 18.6, 18.3, 17.6, 9.5; IR (neat) 2930, 1458, 1404,
1074, 1030 cmꢀ1; HRMS m/z (EI) calcd for C23H36O3Na
[M]+, required: 383.2557, found: 383.2562.
3H), 1.67 (m, 1H), 1.62 (s, 3H), 1.44–1.34 (m, 3H), 1.08
(d, J¼7.0 Hz, 3H), 0.85 (d, J¼7.0 Hz, 3H); 13C NMR
(125 MHz, CDCl3) d 181.1, 179.4, 167.7, 150.6, 140.2,
131.5, 124.3, 119.6, 61.2, 37.1, 36.4, 35.6, 26.2, 26.1, 25.8,
25.7, 21.3, 18.5, 17.7, 17.5, 9.7; IR (neat) 2924, 1732,
1673, 1657, 1454, 1376, 1234 cmꢀ1; HRMS m/z (EI) calcd
for C21H30O3Na [M]+, required: 353.2078, found: 353.2097.
4.1.7. Elisabethadione (3). To a solution of ortho-quinone
12 (20 mg, 0.06 mmol) in benzene (5 mL) at room tempera-
ture under argon was added 4-methylbenzenesulfonic acid
monohydrate (23.0 mg, 0.12 mmol, 2.0 equiv). The mixture
was stirred at room temperature for 2 h. The reaction mix-
ture was diluted with ether (50 mL), washed with water
and brine, dried over Na2SO4, and concentrated. Purification
by column chromatography on silica gel (eluting with 2–7%
ether/pentane) gave the title compound (18 mg, 96%) as
a yellow oil. [a]D25 278.0 (c 0.58, CHCl3); 1H NMR
(500 MHz, CDCl3) d 6.97 (s, OH, 1H), 5.10 (br t,
J¼7.0 Hz, 1H), 2.95 (m, 1H), 2.89 (m, 1H), 2.10–1.94 (m,
2H), 1.93 (s, 3H), 1.88–1.74 (m, 3H), 1.69 (s, 3H), 1.63
(m, 1H), 1.60 (s, 3H), 1.49–1.43 (m, 1H), 1.35–1.21 (m,
2H), 1.10 (d, J¼7.0 Hz, 3H), 0.81 (d, J¼7.0 Hz, 3H); 13C
NMR (125 MHz, CDCl3) d 187.9, 182.9, 150.6, 148.2,
143.1, 131.3, 124.5, 116.8, 36.9, 36.0, 35.7, 26.3, 26.1,
26.0, 25.7, 20.8, 18.1, 17.7, 17.6, 8.2; IR (neat) 3675,
2970, 2920, 1738, 1714, 1406, 1242, 1067 cmꢀ1; HRMS
m/z (EI) calcd for C20H28O3 [M]+, required: 316.2033;
4.1.5. (5R,8S)-5,6,7,8-Tetrahydro-4-methoxy-3,8-di-
methyl-5-((S)-6-methylhept-5-en-2-yl)naphthalene-1,2-
diol (11). To a solution of ethanethiol (2.07 g, 33.31 mmol)
in dry hexanes (15 mL) at 0 ꢁC under argon was added
n-butyllithium (5.20 mL, 8.33 mmol, 1.6 M in hexanes).
The mixture was stirred at room temperature for 30 min.
Then the mixture was concentrated in vacuo to give a white
powder. The white powder and 10 (100 mg, 0.23 mmol)
were dissolved in dry DMF (15 mL) at room temperature
and the mixture was heated to reflux (180 ꢁC oil bath) for
3 h. The reaction mixture was allowed to cool down to
room temperature, acidified with 5% hydrochloric acid,
and extracted with Et2O (2ꢂ50 mL). The combined extracts
were washed with water and brine, dried over Na2SO4, and
concentrated. Purification by column chromatography on
silica gel (eluting with 13% ether/pentane) gave the title
compound (76 mg, 85%) as a yellow oil. [a]2D5 13.0 (c
0.94, CHCl3); 1H NMR (500 MHz, CDCl3) d 5.13 (t,
J¼7.0 Hz, 1H), 4.92 (s, 1H), 4.78 (s, 1H), 3.63 (s, 3H),
3.05 (m, 1H), 2.86 (m, 1H), 2.18 (s, 3H), 2.00 (m, 4H),
1.80 (m, 2H), 1.69 (s, 3H), 1.60 (s, 3H), 1.50 (m, 1H),
1.30 (m, 2H), 1.18 (d, J¼7.0 Hz, 3H), 0.74 (d, J¼7.0 Hz,
3H); 13C NMR (75 MHz, CDCl3) d 150.7, 140.1, 136.9,
130.8, 127.3, 125.3, 124.7, 114.9, 60.5, 37.6, 35.7, 35.5,
26.7, 26.5 (2C), 25.7, 21.6, 18.8, 18.2, 17.6, 9.2; IR (neat)
3419, 2957, 2927, 1450, 1292, 1093, 1008 cmꢀ1; HRMS
m/z (EI) calcd for C21H32O3 [M]+, required: 332.2346;
found: 332.2346.
1
found: 316.2026. H NMR (500 MHz, benzene) d 6.73 (s,
OH, 1H), 5.25 (m, 1H), 2.93 (m, 1H), 2.83 (m, 1H), 2.20–
1.95 (m, 3H), 1.92 (s, 3H), 1.68 (s, 3H), 1.57 (s, 3H), 1.55
(m, 2H), 1.42–1.26 (m, 3H), 1.51 (m, 1H), 0.97 (d,
J¼7.0 Hz, 3H), 0.71 (d, J¼7.0 Hz, 3H).
4.1.8. (1R,4S)-1,2,3,4-Tetrahydro-5,6,8-trimethoxy-4,7-
dimethyl-1-((S)-pent-4-en-2-yl)naphthalene (13).22 To
a stirring solution of 5b (95 mg, 0.28 mmol) and o-nitro-
phenyl selenocyanate (192 mg, 0.85 mmol) in dry THF
(7 mL) under argon at room temperature was added tri-n-
butylphosphine (212 mL, 0.85 mmol). After stirring for
3 h, the reaction mixture was quenched with ethanol
(4 mL) and concentrated. The crude product was used di-
rectly for the next step. 1H NMR (400 MHz, CDCl3)
d 8.28 (d, J¼8.0 Hz, 1H), 7.52 (m, 2H), 7.30 (m, 1H), 3.84
(s, 3H), 3.80 (s, 3H), 3.62 (s, 3H), 3.16 (m, 1H), 2.98–2.83
(m, 3H), 2.17 (s, 3H), 2.10–1.65 (m, 6H), 1.54–1.40 (m,
3H), 1.14 (d, J¼6.8 Hz, 3H), 0.76 (d, J¼6.8 Hz, 3H); 13C
NMR (75 MHz, CDCl3) d 152.8, 149.6, 147.1, 146.9,
134.8, 134.1, 133.4, 129.2, 128.2, 126.4, 125.1, 122.2,
60.5, 60.2, 59.9, 37.3, 35.8, 35.5, 27.0, 26.6, 26.5 (2C),
23.2, 18.7, 18.4, 9.4; IR (neat) 2931, 1513, 1330, 1071,
729 cmꢀ1; HRMS m/z (EI) calculated for C26H35NO5Se
[M]+, required: 521.1675; found: 521.1675.
4.1.6. (5R,8S)-5,6,7,8-Tetrahydro-4-methoxy-3,8-di-
methyl-5-((S)-6-methylhept-5-en-2-yl)naphthalene-1,2-
dione (12). To a solution of diol 11 (76 mg, 0.228 mmol) in
CH3CN (8 mL), a solution of cerium ammonium nitrate
(376 mg, 0.686 mmol, 3.0 equiv) in distilled water (8 mL)
was added by syringe at 0 ꢁC. The resulting red solution
was stirred at 0 ꢁC for 10 min. The reaction mixture was
quenched with water (10 mL) and extracted with Et2O
(2ꢂ40 mL). The combined extracts were washed with water
and brine, dried over Na2SO4, and concentrated. Purification
by column chromatography on silica gel (eluting with 20%
ether/pentane) gave the title compound (58 mg, 77%) as an
To a solution of the above crude product in THF (7 mL) was
slowly added 30% aqueous hydrogen peroxide (0.35 mL) at
0 ꢁC. Stirring was continued for 1 day at room temperature.
Water was added and extracted with ether (twice). The com-
bined organic extracts were washed with water, dried over
Na2SO4, and concentrated. The residue was purified by
column chromatography on silica gel (eluting with 2–5%
ether/pentane) to give 13 (80 mg, 90% yield) as colorless oil.
1H NMR (500 MHz, CDCl3) d 5.80 (m, 1H), 5.02–4.95
1
orange red oil. [a]D25 271.0 (c 0.0317, CHCl3); H NMR
(500 MHz, CDCl3) d 5.11 (br t, J¼7.0 Hz, 1H), 3.92 (s,
3H), 2.89 (m, 1H), 2.65 (m, 1H), 2.06–1.98 (m, 2H), 1.98
(s, 3H), 1.93–1.88 (m, 1H), 1.86–1.73 (m, 2H), 1.70 (s,