A. Abad et al. / Tetrahedron 57 12001) 9727±9735
9733
3.1.10. [3-/20,30-Dimethoxy-50-methylphenyl)-2-methyl-
cyclopent-2-enyloxymethyl] trimethylstannane /15). To
a stirred slurry of pre-washed 5pentane) potassium hydride
540% dispersion oil; 36.3 mg, 0.90 mmol) in THF 51 mL), a
solution of 3 5150 mg, 0.60 mmol) in THF 51 mL) was
added. After the hydrogen evolution had ceased, a solution
of Me3SnCH2I 5329 mg, 1.08 mmol) in THF 50.6 mL) was
added and the mixture was stirred at room temperature for
1 h. The mixture was cooled to 08C and carefully treated
with saturated aqueous NH4Cl solution followed by extrac-
tion with diethyl ether. The organic extracts were washed
with water and brine, dried 5Na2SO4), and concentrated to
give an oil. Flash chromatography, using hexane±ether
59:1) as eluent afforded the stannane 15 5244.2 mg, 95%)
as a yellowish oil; IR nmax 5®lm) 2955, 2932, 2857, 1698,
1583, 1482, 1464, 1351, 1230, 1128, 1052, 1015, 834,
1460, 1344, 1001, 908, 777, 730 cm21; 1H NMR 5400 MHz,
CDCl3) dH 6.63 51H, brs, H-60), 6.51 51H, brs, H-40), 3.85
53H, s, MeO-20), 3.73 51H, dd, 11.7, 12.6 Hz, OCH2), 3.72
51H, dd, 11.7, 11.7 Hz, OCH0 ), 3.68 53H, s, MeO-30), 2.85
2
51H, m, CH), 2.56±2.74 52H, m), 2.1±2.2 51H, m), 1.82±1.9
51H, m), 2.30 53H, brs, Me-50), 1.60 53H, dd, 2.4, 1.6 Hz,
Me-2); 13C NMR 575 MHz, CDCl3) dC 152.38 5C30), 144.30
5C20), 136.33, 134.86, 133.29 and 132.62 5C2, C3, C10 and
C50), 122.12 5C60), 111.80 5C40), 64.84 5CH2O), 60.62
5MeO-20), 55.69 5MeO-30), 52.44 5C1), 36.84 5C4), 26.36
5C5), 21.27 5Me-50), 13.49 5Me-2); HRMS, calcd for
C16H22O3 262.1569, found 262.1558.
For 18: IR nmax 5®lm) 2933, 2873, 2822, 1730, 1585, 1482,
1
1464, 1353, 1231, 1129, 1014, 834, 780 cm21; H NMR
5300 MHz, CDCl3) dH 6.65 51H, brs, H-60), 6.53 51H, brs,
H-40), 4.40 51H, brs, H-1), 3.80 53H, s, MeO-20), 3.70 53H, s,
MeO-30), 3.41 53H, s, MeO-1), 2.8±2.5 52H, m), 2.31 53H, s,
Me-50), 2.20 51H, m), 1.80 51H, m), 1.70 53H, brs, Me-2);
13C NMR 575 MHz, CDCl3) dC 152.4 5C30), 144.6 5C20),
137.6, 135.7, 133.2 and 132.2 5C2, C3, C10 and C50), 122.1
5C60), 111.9 5C40), 89.4 5C1), 60.8 5MeO-20), 55.7
5MeO-30), 55.2 5MeO-1), 35.0 5C4), 28.5 5C5), 21.2
5Me-50), 15.3 5Me-2); MS 5EI) m/z 5relative intensity) 262
5M1, 52), 247 5100), 231 556), 230 550), 77 57); HRMS,
calcd for C16H22O3 262.1569, found 262.1558.
1
767 cm21; H NMR 5400 MHz, CDCl3) dH 6.65 51H, d,
0
0
J2Hz, H-6 ), 6.53 51H, d, J2Hz, H-4 ), 4.38 51H, brt,
H-1), 3.84 53H, s, MeO-20), 3.66 53H, s, MeO-30), 3.77 and
3.6251H each, each d, J10.4 Hz, OCH2Sn), 2.7 51H, m),
2.6 51H, m), 2.30 53H, s, Me-50), 2.2 51H, m), 1.8 51H, m),
1.64 53H, s, Me-2), 0.14 59H, s, Me3Sn); 13C NMR 575 MHz,
CDCl3) dC 152.4 5C30), 144.6 5C20), 137.1, 136.0, 133.2and
132.3 5C3, C2, C50 and C10), 122.2 5C60), 111.8 5C40), 91.2
5C1), 60.8 5MeO-20), 58.25O CH2Sn), 55.7 5MeO-30), 35.1
5C4), 28.0 5C5), 21.3 5Me-50), 12.8 5Me-2), 210.3 5Me3Sn);
MS 5EI) m/z 5relative intensity) 425 5M1, 29), 410 57), 395
520), 318 5100); HRMS, calcd for C19H31O3Sn 425.1289,
found 425.1293.
3.1.12. [2-/20,30-Dimethoxy-50-methyl-phenyl)-1-methyl-
bicyclo[3.1.0]hex-2-yl]methanol /19). Cyclopropanation
of cyclopentene 16 596.5 mg, 0.38 mmol) in the same way
as for 3 afforded, after puri®cation by chromatography using
hexane±ethyl acetate 58:2) as eluent, the cyclopropane±
alcohol 19 577.2mg, 76%) as a white solid; mp 80±81 8C
5from hexane); IR nmax 5®lm) 3514, 3059, 2997, 2934, 2868,
2833, 1603, 1582, 1478, 1463, 1414, 1324, 1229, 1147,
3.1.11. [1-/20,30-Dimethoxy-50-methylphenyl)-2-methyl-
cyclopent-2-enyl]methanol /16). A solution of trimethyl-
stannane 15 5145 mg, 0.34 mmol) in hexane 53.3 mL) was
treated dropwise with BuLi 51.6 M in hexane, 0.23 mL,
0.37 mmol) at 2788C. After 2h at the same temperature,
the mixture was allowed to warm slowly to 2108C over-
night. The reaction was quenched with water and extracted
with diethyl ether. The combined organic extracts were
dried 5MgSO4) and then evaporated under reduced pressure.
Flash chromatography of the residue, using hexane±ethyl
acetate 5from 8:2to 6:4) as eluent, gave, in order of elution,
methyl ether 18 53.6 mg, 4%), the [2,3]-rearrangement
1006, 835 cm21 1H NMR 5400 MHz, CDCl3) dH 6.86
;
51H, brs, H-60), 6.64 51H, brs, H-40), 4.11 51H, dd, J
11.6, 7.1 Hz, CH2O), 3.93 51H, dd, J11.6, 8.3 Hz,
CH2O), 3.86 53H, s, MeO-30), 3.84 53H, s, MeO-20), 3.19
51H, dd, J8.3, 7.1 Hz, OH), 2.33 53H, s, Me-50), 2.01 and
1.66 51H each, each m, CH2), 1.43±1.16 53H, m, CH2 and
H-5), 1.13 53H, s, Me-1), 0.50 51H, t, J5.0 Hz, H-6), 0.37
51H, ddd, J7.9, 5.0, 0.8 Hz, H-6); 13C NMR 575 MHz,
1
product 16 549.0 mg, 55%) and a 3:2mixture 5 H NMR
0
CDCl3) dC 153.0 5C30), 143.9 5C20), 137.3 and 133.25C5
analysis) of alcohols 3 and the [1,2]-rearrangement product
17 531.1 mg, 35%). Compound 17 was separated from
the above mixture with 3 by MPLC chromatography,
using hexane±ethyl acetate 58:2) as eluent.
and C10), 123.2 5C60), 110.8 5C40), 68.7 5CH2O), 61.3
5MeO-20), 55.6 5MeO-30), 54.4 5C2), 35.2 5C3), 26.6 5C4),
33.1 5C1), 28.2 5C5), 21.9 5Me-50), 19.5 5Me-1), 14.3 5C6);
MS 5EI) m/z 5relative intensity) 276 5M1, 49), 258 546), 245
5100), 231 530), 208 555), 165 558); HRMS, calcd for
C17H24O3 276.1725, found 276.1728.
For 16: colourless oil; IR nmax 5®lm) 3457, 3032, 2934,
2851, 1583, 1480, 1464, 1416, 1316, 1233, 1149, 1012,
1
834, 780 cm21; H NMR 5300 MHz, CDCl3) dH 6.63 51H,
brs, H-60), 6.50 51H, brs, H-40), 5.70 51H, bs, H-3), 3.96 52H,
m, CH2O), 3.84 53H, s, MeO-20), 3.81 53H, s, MeO-30),
2.37±2.00 54H, m), 2.30 53H, s, Me-50), 1.65 53H, m,
Me-2); 13C NMR 575 MHz, CDCl3) dC 152.9 5C30), 145.2
5C20), 142.6 5C2), 137.4 and 133.1 5C10 and C50), 128.8
5C3), 121.2 5C60), 111.5 5C40), 66.9 5CH2O), 60.7 5MeO-
20), 60.0 5C1), 55.6 5MeO-30), 36.8 and 30.5 5C4 and C5),
21.6 5Me-2), 14.1 5Me-50); MS 5EI) m/z 5relative intensity)
262 5M1, 26), 232 533), 231 5100), 200 513), 175 519);
HRMS, calcd for 262.1569 C16H22O3, found 262.1559.
3.1.13. 4-/20,30-Dimethoxy-50-methyl-phenyl)-1,7-dimethyl-
2-oxa-bicyclo[2.2.1]heptane /23). To a solution of cyclo-
propane±alcohol 19 59.5 mg, 0.035 mmol) in AcOH 51 mL)
was added a catalytic amount of PtO2 530 mg), and the
resulting suspension was stirred under a hydrogen atmos-
phere 54 atm.) for 15 h. The catalyst was removed by ®l-
tration and the ®ltrate was concentrated to give the crude
product that was puri®ed by ¯ash chromatography, with
pentane±ether 57:3) as eluent, to give the compound 23
54.6 mg, 48%) as a colourless oil; IR nmax 5®lm) 2963,
2931, 2872, 2837, 1586, 1486, 1463, 1419, 1326, 1274,
1
For 17: IR nmax 5®lm) 3447, 2930, 2853, 1696, 1577, 1480,
1240, 1136, 1038, 1010, 988, 864, 832 cm21; H NMR