T. Nemoto et al. / Tetrahedron 59 (2003) 6889–6897
6895
1 1
1138, 962, 948 cm2 ; H NMR (CDCl ) d 1.24 (s, 3H), 1.37
0
Found: C, 62.10; H, 6.55.
.76 CHCl ). Anal. calcd for C H O : C, 62.33; H, 6.54.
3 16 20 6
3
(s, 3H), 1.83 (s, 1H), 3.19 (dd, J¼9.5, 15.9 Hz, 1H), 3.25
(
dd, J¼8.3, 15.9 Hz, 1H), 4.74 (dd, J¼8.3, 9.5 Hz, 1H), 6.21
4
.1.8. (2)-Peucedanol (7). Concentrated HCl (0.5 mL) was
(d, J¼9.5 Hz, 1H), 6.73 (s, 1H), 7.22 (s, 1H), 7.59 (d,
1
3
added to a stirred solution of the diol (27.2 mg, 0.088 mmol)
in THF (2.2 mL) and water (1.7 mL) at 358C and the
reaction mixture was stirred for 17 h at the same
temperature. After cooling to room temperature, the
resulting mixture was extracted with CH Cl (5 mL£2),
J¼9.5 Hz, 1H); C NMR (CDCl ) d 24.3, 26.1, 29.5, 71.6,
3
91.1, 97.9, 112.2, 112.7, 123.4, 125.1, 143.7, 155.6, 161.4,
163.1; MS m/z 246 [M ]; [a] ¼þ21.7 (c 0.9 CHCl )
þ
23
D
3
2
0b
23
D
(lit. ([a] ¼þ20.3). Anal. calcd for C H O : C, 68.28;
14 14 4
H, 5.73. Found: C, 68.01; H, 5.89.
2
2
washed with brine (5 mL), and dried over Na SO . After
2
4
concentration in vacuo, the residue was purified by flash
column chromatography (SiO , MeOH–CH Cl 1:40) to
give (2)-peucedanol (7) (21.4 mg, 92%) as a white solid. IR
4.1.11. (2)-Prantschimgin (3). LiHMDS (0.05 mL,
0.05 mmol, 1 M solution in THF) was added to a stirred
solution of 5 (9.9 mg, 0.04 mmol), and DMAP (12.2 mg,
0.1 mmol) in THF (1 mL) at 2408C. After the reaction
mixture was stirred for 15 min at the same temperature,
senecioyl chloride (0.022 mL, 0.2 mmol) was added. The
stirred solution was warmed to room temperature for 2 h and
then quenched by the addition of saturated aqueous sodium
hydrogen carbonate (1 mL). After dilution with ethyl
acetate (2 mL), the aqueous layer was extracted with ethyl
acetate (2£4 mL), and the combined organic layers were
washed with brine (4 mL) and dried over Na SO . After
2
2
2
KBr) n 3385, 2976, 1708, 1628, 1577, 1387, 1147 cm2
1
;
H NMR (acetone-d ) d 1.24 (s 3H), 1.25 (s, 3H), 2.68 (dd,
(
1
6
J¼10.1, 14.4 Hz, 1H), 2.79 (s(b), 2H), 3.02 (dd, J¼1.8,
1
4.4 Hz, 1H), 3.65 (dd, J¼1.8, 10.1 Hz, 1H), 6.13 (d,
J¼9.5 Hz, 1H), 6.71 (s, 1H), 7.41 (s, 1H), 7.81 (d,
J¼9.5 Hz, 1H) (phenolic proton was not observed in
1
3
acetone-d ); C NMR (acetone-d ) d 25.5, 25.6, 33.9,
6
6
7
1
2.8, 80.4, 103.9, 112.8, 113.0, 125.9, 131.4, 144.7, 155.7,
þ
25
D
60.9, 161.3; MS m/z 264 [M ]; [a] ¼238.8 (c 0.57
2
4
EtOH). Anal. calcd for C H O : C, 63.63; H, 6.10. Found:
1
concentration in vacuo, the residue was purified by flash
column chromatography (SiO , hexane–ethyl acetate 5:1 to
4 16 5
C, 63.70; H, 6.31.
2
2:1) to give (2)-prantschimgin (3) (9.5 mg, 72%) as a white
solid. IR (KBr) n 2922, 1717, 1706, 1626, 1267, 1228,
4.1.9. 6-[(2S)-2,3-Dihydroxy-3-methylbutyl]-7-(trifluoro-
methanesulfonyl)chromen-2-one (6). Trifluoromethansul-
1123 cm2 ; H NMR (CDCl ) d 1.53 (s, 3H), 1.60 (s, 3H),
1 1
3
fonic anhydride (0.05 mL, 0.297 mmol) was added
1.85 (d, J¼1.2 Hz, 3H), 2.10 (d, J¼1.2 Hz, 3H), 3.23 (m,
2H), 5.14 (dd, J¼8.0, 9.5 Hz, 1H), 5.55 (t, J¼1.2 Hz, 1H),
6.21 (d, J¼9.5 Hz, 1H), 6.74 (s, 1H), 7.21 (s, 1H), 7.59 (d,
dropwise to an ice-cold solution of
7
(70.5 mg,
.267 mmol) and diisopropylethylamine (0.116 mL,
.667 mmol) in CH Cl (7.5 mL) and the mixture was
0
0
1
3
J¼9.5 Hz, 1H); C NMR (CDCl ) d 20.1, 21.3, 22.3, 27.4,
2
2
3
stirred for 10 min at the same temperature. After the
reaction was quenched by the addition of saturated aqueous
sodium hydrogen carbonate (5 mL), the aqueous layer was
extracted with CH Cl (2£5 mL), and the combined organic
29.6, 81.3, 88.7, 98.0, 112.3, 112.7, 117.0, 123.2, 124.6,
143.6, 155.8, 156.6, 161.4, 163.5, 165.8; MS m/z 328 [M ];
þ
2
5
þ
[a] ¼234.6 (c 0.72 CHCl ); HRMS (M ) calcd for
D
3
C H O 328.1311. Found 328.1315.
19 20 5
2
2
layers were washed with brine (5 mL), dried over Na SO ,
2
4
and evaporated in vacuo. The residue was purified by flash
column chromatography (SiO , hexane–ethyl acetate 1:1)
4.1.12. 6-[(2S)-3-Hydroxy-3-methyl-2-(triethylsilyloxy)-
butyl]-7-(trifluoromethanesulfonyl)chromen-2-one (25).
Chlorotriethylsilane (0.017 mL, 0.102 mmol) was added to
an ice-cold solution of 6 (13.5 mg, 0.034 mmol) and
imidazole (9.3 mg, 0.136 mmol) in CH Cl (1.2 mL). The
2
to give 6 (97.5 mg, 92%) as a white solid. IR (KBr) n 3497,
2
1 1
3
(
402, 1698, 1426, 1248, 1223, 1137, 887 cm ; H NMR
CDCl ) d 1.30 (s, 3H), 1.35 (s, 3H), 1.80 (s, 1H), 2.29 (d,
3
2
2
J¼4.6 Hz, 1H), 2.70 (dd, J¼11.0, 14.3 Hz, 1H), 3.05 (dd,
reaction mixture was stirred for 12 h at room temperature
and then saturated aqueous sodium hydrogen carbonate
(2 mL) was added. The aqueous layer was extracted with
CH Cl (2£4 mL), the combined organic layers were
washed with brine (4 mL) and dried over Na SO . After
2 4
J¼1.6, 14.3 Hz, 1H), 3.65 (ddd, J¼1.6, 4.6, 11.0 Hz, 1H),
6
.47 (d, J¼9.5 Hz, 1H), 7.29 (s, 1H), 7.62 (s, 1H), 7.68 (d,
1
3
J¼9.5 Hz, 1H); C NMR (CDCl ) d 23.5, 26.6, 31.9, 73.0,
3
2
2
7
1
7.4, 110.2, 117.8, 118.5 (q, 320 Hz), 118.6, 129.0, 131.4,
42.3, 149.5, 153.0, 159.5; MS m/z 396 [M ]; [a] ¼217.3
þ
23
D
concentration in vacuo, the residue was purified by flash
column chromatography (SiO , hexane–ethyl acetate 5:1)
(
c 0.53 CHCl ). Anal. calcd for C H F O S: C, 45.46; H,
7
3
15 15
3
2
3
.81. Found: C, 45.21; H, 3.79.
to give 25 (15.9 mg, 92%) as a colorless oil. The
enantiomeric excess of this product was determined by
chiral stationary-phase HPLC analysis (DAICEL
CHIRALCEL OD, i-PrOH–hexane 2:98, flow rate
0.3 mL/min, tR 25.0 min (2R)-isomer and 26.9 min (2S)-
isomer). IR (KBr) n 3495, 2958, 2879, 1748, 1425, 1218,
4
0
.1.10. (1)-Marmesin (5). Na(O-t-Bu) (0.415 mL,
.196 mmol, 0.427 M solution in THF) was added to a
stirred solution of 6 (51.7 mg, 0.1305 mmol), Pd(OAc)2
2.94 mg, 0.01 31 mmol), and DPPF (14.5 mg,
.0262 mmol) in toluene (3 mL) at room temperature.
(
0
1140, 1101, 1065, 880 cm2 ; H NMR (CDCl ) d 0.19–
1 1
3
After stirring for 1 h at 908C, the reaction mixture was
then poured into water (5 mL), the aqueous layer was
extracted with ethyl acetate (2£10 mL), and the combined
organic layers were washed with brine (10 mL), dried over
Na SO , and evaporated in vacuo. The residue was purified
0.35 (m, 6H), 0.79 (t, J¼7.9 Hz, 9H), 1.25 (s, 3H), 1.26 (s,
3H), 1.90 (s, 1H), 2.69 (dd, J¼10.1, 14.0 Hz, 1H), 3.11 (dd,
J¼2.5, 14.0 Hz, 1H), 3.80 (dd, J¼2.5, 10.1 Hz, 1H), 6.49 (d,
J¼9.5 Hz, 1H), 7.31 (s, 1H), 7.47 (s, 1H), 7.67 (d,
1
3
J¼9.5 Hz, 1H); C NMR (CDCl ) d 5.0 (£3), 6.8 (£3),
2
4
3
by flash column chromatography (SiO , hexane–ethyl
2
24.3, 26.3, 33.7, 73.0, 79.3, 110.1, 118.0, 118.3, 118.6
(J¼320 Hz), 129.2, 132.1, 141.8, 149.7, 153.0, 159.4; MS
acetate 2:1) to give (þ)-marmesin (5) (25.6 mg, 80%) as a
þ
22
D
white solid. IR (KBr) n 3480, 2979, 1704, 1631, 1572, 1269,
m/z 481 [M 2CH CH ]; [a] ¼218.2 (c 0.79
2
3