2038 Bull. Chem. Soc. Jpn., 75, No. 9 (2002)
“Syn-Effect” on (E)-α-Fluorovinylic Sulfones
(2H, d, J = 8.07 Hz), 7.85 (2H, d, J = 8.07 Hz). Found: C, 50.77;
H, 4.82%. Calcd for C8H9FO2S: C, 51.05; H, 4.82%.
hexane/AcOEt); IR (KBr) 3023, 2962, 2930, 2865, 1594, 1496,
1455, 1321, 1308, 1292, 1152, 1089, 1036, 1018, 923, 821, 801,
757, 704, 663 cm−1; 1H NMR (CDCl3) δ 2.12–2.26 (1H, m), 2.34–
2.53 (1H, m), 2.46 (3H, s), 2.77 (1H, ddd, J = 8.18, 8.29, 13.92
Hz), 2.94 (1H, ddd, J = 5.14, 8.76, 13.92 Hz), 5.02 (1H, ddd, J =
2.93, 10.24, 48.32 Hz), 7.17–7.32 (5H, m), 7.38 (2H, d, J = 8.29
Hz), 7.80 (2H, d, J = 8.29 Hz). Found: C, 65.76; H, 5.94%.
Calcd for C16H17FO2S: C, 65.73; H, 5.86%.
Preparation of 1-Fluoro-1-tosylbutane (2a). To a mixed so-
lution of fluoromethyl p-tolyl sulfone (1, 376 mg, 2 mmol) and
HMPA (0.52 mL, 3.0 mmol) in THF (20 mL) was added a solution
of n-BuLi in hexane (1.34 mL, 2.1 mmol, 1.57 M) at −72 °C un-
der a nitrogen atmosphere, followed by the addition of 1-iodopro-
pane (0.24 mL, 2.4 mmol) after 30 min. The reaction mixture was
stirred for 10 min at −72 °C and for 1 h at room temperature, and
then quenched by the addition of a saturated NH4Cl solution (2
mL). After removing the solvent under reduced pressure, the or-
ganic substances were extracted with ethyl acetate, followed by
washing with brine and drying over Na2SO4. An alkylated product
2a was isolated by flash column chromatography (SiO2, hexane/
AcOEt = 10/1) in 76% yield (347 mg). Mp 40.8–41.0 °C (from
hexane/CHCl3); IR (KBr) 2966, 2878, 1595, 1494, 1466, 1388,
1321, 1292, 1246, 1184, 1154, 1106, 1086, 1036, 1019, 960, 850,
1-Fluoro-3-(methoxymethoxy)-1-tosylpropane (2g).
oil; IR (neat) 3070, 2932, 2883, 2825, 1596, 1455, 1384, 1329,
1224, 1151, 1110, 1085, 1045, 920, 815, 760, 725, 704, 666 cm−1
An
;
1H NMR (CDCl3) δ 1.98–2.10 (1H, m), 2.37–2.55 (1H, m), 2.45
(3H, s), 3.32 (3H, s), 3.65 (1H, ddd, J = 3.90, 10.00, 10.12 Hz),
3.71–3.76 (1H, m), 4.57 (1H, d, J = 6.59 Hz), 4.60 (1H, d, J =
6.59 Hz), 5.32 (1H, ddd, J = 2.68, 10.00, 48.30 Hz), 7.37 (2H, d,
J = 8.29 Hz), 7.81 (2H, d, J = 8.29 Hz). MS m/z 276 (M+,
0.11%), 245 (3.79), 231 (19.87), 215 (22.93), 157 (23.36), 156
(20.04), 139 (36.05), 121 (19.43), 105 (9.76), 91 (42.75), 75
(9.18), 65 (16.71), 58 (28.11), 45 (100.00), 43 (83.38).
1
821, 743, 704, 665 cm−1; H NMR (CDCl3) δ 0.98 (3H, t, J =
7.32 Hz), 1.45–1.70 (2H, m), 1.78–1.93 (1H, m), 2.00–2.20 (1H,
m), 2.47 (3H, s), 5.08 (1H, ddd, J = 2.92, 10.04, 48.56 Hz), 7.39
(2H, d, J = 8.32 Hz), 7.82 (2H, d, J = 8.32 Hz). Found: C, 57.15;
H, 6.58%. Calcd for C11H15FO2S: C, 57.37; H, 6.56%.
In a similar manner, 2b–g were prepared in good yields. Their
physical and spectral data are given in the following.
1-Fluoro-1-tosylpentane (2b). An oil; IR (neat) 3060, 2960,
2890, 1595, 1495, 1460, 1400, 1380, 1310, 1230, 1150, 1080,
1040, 1015, 970, 895, 810, 775, 715, 700 cm−1; 1H NMR (CDCl3)
δ 0.92 (3H, t, J = 7.08 Hz), 1.30–1.62 (4H, m), 1.78–1.93 (1H,
m), 2.03–2.24 (1H, m), 2.46 (3H, s), 5.06 (1H, ddd, J = 2.92,
10.04, 48.84 Hz), 7.38 (2H, d, J = 8.04 Hz), 7.81 (2H, d, J = 8.04
Hz) MS m/z 244 (M+, 4.44%), 157 (55.09), 156 (85.25), 92
(100.00), 91 (90.57), 69 (39.55), 65 (49.32), 43 (44.05), 41
(60.25).
Preparation of 1-Fluoro-1-tosyl-1-butene (3a).
In a dry
flask, n-BuLi in hexane (0.73 mL, 1.13 mmol, 1.55 M) was added
to a solution of [(CH3)2CH]2NH (0.148 mL, 1.13 mmol) in THF (4
mL) at −72 °C and the mixture was stirred for 30 min at the tem-
perature, followed by the dropwise addition of a solution of 1-flu-
oro-1-tosylbutane (2a, 130 mg, 0.565 mmol) in THF (2 mL). Af-
ter stirring for 30 min at −72 °C, MeSSMe (0.055 mL, 0.6215
mmol) was added to the reaction mixture, and the mixture was
stirred for 6 h at room temperature. Then, the reaction mixture
was quenched with phosphate-buffer (pH 7). After evaporating
the organic solvent, the product was extracted with ethyl acetate,
followed by washing with brine and drying over Na2SO4. After
removal of the solvent, the crude product was purified by prepara-
tive TLC (hexane/AcOEt = 5/1) to give methylthiolated product
(82 mg, 0.297 mmol). The sulfide was then oxidized with m-
CPBA (ca. 70% pure, 81 mg, 0.326 mmol) in CH2Cl2 at room
temperature overnight. After the usual work-up, the resulting sul-
foxide was refluxed in toluene for 12 h to afford 3a as a mixture of
(E)- and (Z)-isomers, which were isolated by preparative TLC
(hexane/AcOEt = 5/1) in 40% overall yield (51 mg, E/Z = 96/4)
from 2a. Mp 48.5–49.0 °C [(E)-isomer, from hexane/AcOEt]; IR
of (E)-isomer (KBr) 3059, 2976, 2932, 2872, 1670, 1595, 1495,
1459, 1440, 1345, 1329, 1306, 1172, 1141, 1091, 1043, 1017,
817, 740, 666 cm−1; 1H NMR (CDCl3) of (E)-form δ 1.07 (3H, t, J
= 7.56 Hz), 2.23 (2H, dp, J = 2.44, 7.56 Hz), 2.46 (3H, s), 6.22
(1H, dt, J = 32.69, 7.56 Hz), 7.37 (2H, d, J = 8.30 Hz), 7.82 (2H,
d, J = 8.30 Hz). 1H NMR (CDCl3) of (Z)-form δ 1.10 (3H, dt, J
= 0.73, 7.56 Hz), 2.46 (3H, s), 2.65 (2H, ddq, J =1.71, 8.54, 7.56
Hz), 5.81 (1H, dt, J = 21.96, 8.54 Hz), 7.37 (2H, d, J = 8.30 Hz),
7.84 (2H, d, J = 8.30 Hz). Found: C, 57.75; H, 5.76%. Calcd for
C11H13FO2S: C, 57.87; H, 5.74%.
1-Fluoro-4-methyl-1-tosylpentane (2c).
An oil; IR (neat)
2975, 2890, 1590, 1465, 1325, 1300, 1150, 1085, 1070, 1025,
895, 805, 715, 695, 655 cm−1; 1H NMR (CDCl3) δ 0.90 (3H, d, J
= 6.60 Hz), 0.91 (3H, d, J = 6.60 Hz), 1.31–1.52 (2H, m), 1.54–
1.66 (1H, m), 1.79–1.94 (1H, m), 2.06–2.26 (1H, m), 2.47 (3H, s),
5.04 (1H, ddd, J = 2.92, 10.00, 48.84 Hz), 7.39 (2H, d, J = 8.32
Hz), 7.82 (2H, d, J = 8.32 Hz). MS m/z 258 (M+, 34.44%), 157
(99.61), 156 (100.00), 139 (32.87), 92 (90.47), 91 (47.37), 83
(17.74), 65 (16.94), 61 (25.68), 57 (16.56), 55 (20.33).
1-Fluoro-4,4-dimethyl-1-tosylpentane (2d).
(neat) 3065, 2958, 2869, 1597, 1469, 1397, 1367, 1329, 1303,
1249, 1153, 1091, 1070, 1018, 994, 905, 816, 735, 704, 662 cm−1
An oil; IR
;
1H NMR (CDCl3) δ 0.90 (9H, s), 1.34 (1H, ddd, J = 4.64, 12.14,
13.17 Hz), 1.49 (1H, ddd, J = 4.64, 12.93, 13.17 Hz), 1.80–1.94
(1H, m), 2.03–2.22 (1H, m), 2.47 (3H, s), 5.01 (1H, ddd, J = 2.93,
10.00, 48.79 Hz), 7.39 (2H, d, J = 8.29 Hz), 7.82 (2H, d, J = 8.29
Hz). MS m/z 272 (M+, 21.75%), 257 (78.08), 157 (100.00), 156
(89.88), 139 (35.02), 92 (21.51), 91 (20.05).
In a similar manner, 3b–g were prepared in good yields. Their
physical and spectral data are given in the following.
3-Ethoxy-1-fluoro-1-tosylpropane (2e).
An oil; IR (neat)
3000, 2890, 1740, 1595, 1490, 1445, 1380, 1330, 1305, 1240,
1215, 1150, 1110, 1080, 1040, 1015, 980, 810, 760, 710, 700, 658
1-Fluoro-1-tosyl-1-pentene (3b). Mp 31.5 °C [(E)-isomer,
from hexane]; IR of (E)-isomer (KBr) 3059, 2955, 2921, 2865,
1664, 1595, 1460, 1439, 1334, 1306, 1164, 1130, 1092, 1043,
980, 882, 817, 799, 731, 665 cm−1; 1H NMR (CDCl3) of (E)-form
δ 0.92 (3H, t, J = 7.34 Hz), 1.49 (2H, sx, J = 7.34 Hz), 2.19 (2H,
ddt, J = 2.20, 7.89, 7.34 Hz), 2.45 (3H, s), 6.23 (1H, dt, J =
32.65, 7.89 Hz), 7.37 (2H, d, J = 8.25 Hz), 7.83 (2H, d, J = 8.25
Hz). 1H NMR (CDCl3) of (Z)-form δ 0.97 (3H, t, J = 7.34 Hz),
1.50 (2H, sx, J = 7.34 Hz), 2.46 (3H, s), 2.62 (2H, m), 5.81 (1H,
dt, J = 22.19, 8.44 Hz), 7.37 (2H, d, J = 8.25 Hz), 7.83 (2H, d, J
1
cm−1; H NMR (CDCl3) δ 1.17 (3H, t, J = 7.04 Hz), 1.96–2.10
(1H, m), 2.47 (3H, s), 2.15–2.54 (1H, m), 3.41–3.72 (4H, m), 5.33
(1H, ddd, J = 2.68, 10.24, 48.56 Hz), 7.38 (2H, d, J = 8.28 Hz),
7.82 (2H, d, J = 8.28 Hz). MS m/z 261 (M+ + 1, 0.87%), 231
(5.20), 216 (9.78), 157 (58.46), 139 (25.17), 105 (18.24), 104
(21.70), 92 (30.26), 91 (59.94), 76 (20.33), 65 (33.80), 59
(100.00), 31 (70.54).
1-Fluoro-3-phenyl-1-tosylpropane (2f).
Mp 122 °C (from