2300
J. Moïse et al.
PAPER
MS (CI, NH3): m/z = 252 (M + NH4)+.
HRMS: m/z calcd for C6H10ClF2O3S: 235.0007 (M + H)+; found:
CF2), –122.5 (2 F, m, CF2), –123.3 (2 F, m, CF2), –126.7 (2 F, m,
CF2).
235.0003.
Compound 7c
1H NMR (300 MHz, CDCl3): d = 6.33 (1 H, dd, J = 2.9, 5.6 Hz, H3),
6.17 (1 H, dd, J = 3.3, 5.6 Hz, H2), 3.52 (1 H, m, H1), 3.23 (1 H, dd,
J = 3.6, 8.2 Hz, H5), 3.14 (1 H, m, H4), 1.67 (1 H, dd, J = 3.6, 7.5
Hz, H6¢), 1.54 (3 H, m, H6, H7, H7¢).
13C NMR (77 MHz, CDCl3): d = 140.2 (C2), 134.0 (C3), 57.6 (C5),
45.3 (C7), 43.2 (C1), 42.8 (C4), 27.4 (C6).
Ethyl Difluoro(vinylsulfinyl)acetate (3)
DBU (2.75 mL, 18.4 mmol) was added dropwise to a solution of 6
(4.3 g, 18.4 mmol) in THF (73 mL). The reaction mixture was
stirred overnight and was fractionally distilled under reduced pres-
sure to give 2.52 g (70%) of 3 as a colorless liquid; bp 113–115 °C/
15 mmHg.
IR (neat): 2986, 2929, 1777, 1372, 1311, 1127 cm–1.
1H NMR (300 MHz, CDCl3): d = 6.66 (1 H, dd, J = 16.4, 9.9 Hz),
6.27 (2 H, m), 4.39 (2 H, q, J = 7.2, OCH2), 1.36 (3 H, t, CH3).
13C NMR (77 MHz, CDCl3): d = 158.8 (t, J = 28.3 Hz), 134.3 (t,
J = 4.0 Hz), 127.6 (t, J = 1.1 Hz), 118.1 (t, J = 300.7 Hz), 64.2, 13.8.
19F NMR (282 MHz, CDCl3): d = –109.4 (1 F, d, J = 234 Hz),
–105.4 (1 F, d).
MS (CI, NH3): m/z = 199 (M + H)+.
HRMS: m/z calcd for C6H9F2O3S: 199.0240 (M + H)+; found:
19F NMR (282 MHz, CDCl3): d = –81.3 (3 F, m, CF3), –111.6 (1 F,
d, J = 251 Hz, SOCF2), –121.1 (2 F, m, CF2), –121.3 (1 F, d,
SOCF2), –122.4 (2 F, m, CF2), –123.3 (2 F, m, CF2), –126.6 (2 F, m,
CF2).
Compound 7d
1H NMR (300 MHz, CDCl3): d = 6.34 (1 H, dd, J = 3.0, 5.6 Hz, H3),
6.19 (1 H, dd, J = 3.0, 5.6, H2), 3.23 (1 H, m, H1), 3.08 (1 H, m, H4),
2.85 (1 H, m, H5), 2.46 (1 H, m, H7¢), 1.55 (3 H, m, H6, H6¢, H7).
19F NMR (282 MHz, CDCl3): d = –81.2 (3 F, m, CF3), –112.8 (1 F,
d, J = 251 Hz, SOCF2), –119.3 (1 F, d, SOCF2), –121.2 (2 F, m,
CF2), –122.4 (2 F, m, CF2), –123.2 (2 F, m, CF2), –126.6 (2 F, m,
CF2).
199.0238.
Anal. Calcd for C6H8F2O3S: C, 36.96; H, 4.07. Found: C, 36.63; H,
3.98.
Ethyl Difluoro(bicyclo[2.2.1]hept-5-ene-2-sulfinyl)acetate (8)
A solution of the dienophile 3 (0.45 g, 2.29 mmol) and freshly dis-
tilled cyclopentadiene (1.51 g, 22.92 mmol) in CH2Cl2 (9 ml) was
stirred at r.t. Cyclopentadiene (1.51 g, 22.92 mmol) was added ev-
ery 12 h during 2 d. After concentration of the mixture at reduced
pressure, the residue was purified by column chromatography using
pentane–Et2O (9:1) as eluent to afford 4 diastereomers in a
75.7:15.1:7:2.2 ratio and in 75% (605 mg) overall yield as a color-
less oil.
IR (neat): 2991, 2934, 1751, 1311, 1152, 1127 cm–1.
MS (CI, NH3): m/z = 265 (M + H)+.
HRMS: m/z calcd for C11H15F2O3S: 265.0710 (M + H)+; found:
265.0708.
5-(Tridecafluorohexane-1-sulfinyl)bicyclo[2.2.1]hept-2-ene (7)
A solution of the dienophile 2 (0.20 g, 0.51 mmol), freshly distilled
cyclopentadiene (0.34 g, 5.10 mmol) and ytterbium triflate (0.32 g,
0.51 mmol) in CH2Cl2 (2 mL) was stirred overnight and filtered
through Celite 545®. After concentration at reduced pressure, the
residue was purified by chromatography on preparative plates using
pentane–Et2O (9:1) as eluent to afford 4 diastereomers in a
70:11:15:4 ratio and an 84% (235 mg) overall yield as a white solid;
mp 68.3–68.6 °C.
IR (Nujol): 2966, 2848, 1460, 1373 cm–1.
MS (CI, NH3): m/z = 461 (M + H)+, 478 (M + NH4)+.
HRMS: m/z calcd for C13H10F13OS: 461.0245 (M + H)+; found:
461.0243.
Anal. Calcd for C11H14F2O3S: C, 49.99; H, 5.34. Found: C, 49.61;
H, 5.36.
Anal. Calcd for C13H9F13OS: C, 33.93; H, 1.97. Found: C, 34.02; H,
2.05.
Compound 8a
1H NMR (300 MHz, CDCl3): d = 6.30 (1 H, dd, J = 3.2, 5.8 Hz, H2),
6.21 (1 H, dd, J = 2.6, 5.9 Hz, H3), 4.45 (2 H, q, J = 6.9 Hz, OCH2),
3.82 (1 H, ddd, J = 3.7, 3.9, 7.5 Hz, H5), 3.44 (1 H, m, H4), 3.01 (1
H, m, H1), 1.92 (1 H, m, H6¢), 1.65 (1 H, m, H7), 1.40 (4 H, m, CH3,
H7¢), 1.03 (1 H, m, H6).
Compound 7a
1H NMR (300 MHz, CDCl3): d = 6.35 (1 H, dd, J = 3.9, 5.6 Hz, H2),
6.23 (1 H, dd, J = 2.6, 5.6 Hz, H3), 4.01 (1 H, ddd, J = 3.6, 3.9, 9.1
Hz, H5), 3.51 (1 H, m, H4), 3.09 (1 H, m, H1), 1.95 (1 H, dd,
J = 3.6, 7.2 Hz, H6¢), 1.68 (1 H, m, H7¢), 1.40 (1 H, m, H7), 1.14 (1
H, ddd, J = 3.6, 6.6 Hz, H6).
13C NMR (77 MHz, CDCl3): d = 160.1 (t, J = 27.7 Hz, CO) 139.26
(C2), 132.1 (C3), 119.6 (t, J = 304.5 Hz, CF2), 64.3 (OCH2), 58.7
(C5), 48.1 (C7), 44.5 (C4), 42.3 (C1), 25.8 (C6), 13.9 (CH3).
13C NMR (77 MHz, CDCl3): d = 139.5 (C2), 132.0 (C3), 58.8 (C5),
48.1 (C7), 44.9 (C4), 42.3 (C1), 26.0 (C6).
19F NMR (282 MHz, CDCl3): d = –81.4 (3 F, m, CF3), –111.5 (1 F,
d, J = 251 Hz, SOCF2), –121.2 (2 F, m, CF2), –121.7 (1 F, d,
SOCF2), –122.5 (2 F, m, CF2), –123,3 (2 F, m, CF2), –126.7 (2 F, m,
CF2).
19F NMR (282 MHz, CDCl3): d = –107.1 (1 F, d, J = 226.3 Hz,
CF2), –109.8 (1 F, d, CF2).
Compound 8b
1H NMR (300 MHz, CDCl3): d = 6.30 (1 H, dd, J = 2.90, 5.6 Hz,
H2), 6.02 (1 H, dd, J = 3.0, J = 5.9 Hz, H3), 4.45 (2 H, q, J = 6.9 Hz,
OCH2), 3.79 (1 H, ddd, J = 3.6, 3.7, 8.9 Hz, H5), 3.23 (1 H, m, H4),
3.06 (1 H, m, H1), 2.13 (1 H, m, H6¢), 1.75 (1 H, m, H6), 1.60 (1 H,
m, H7), 1.40 (4 H, m, CH3, H7¢).
Compound 7b
1H NMR (300 MHz, CDCl3): d = 6.29 (1 H, dd, J = 3.3, 5.6 Hz, H2),
5.94 (1 H, dd, J = 3.0, 5.9 Hz, H3), 3.89 (1 H, dt, J = 3.7, 9.1 Hz,
H5), 3.51 (1 H, m, H4), 3.24 (1 H, m, H1), 2.15 (1 H, m, H7¢), 1.85 (1
H, m, H7), 1.69 (1 H, m, H6), 1.45 (1 H, m, H6¢).
13C NMR (77 MHz, CDCl3): d = 160.0 (t, J = 28.0 Hz, CO) 139.0
(C2), 131.8 (C3), 118.8 (t, J = 296.5 Hz, CF2), 64.3 (OCH2), 59.1
(C5), 49.6 (C7), 44.8 (C4), 41.7 (C1), 26.6 (C6), 14.0 (CH3).
13C NMR (77 MHz, CDCl3): d = 139.4 (C2), 131.3 (C3), 59.2 (C5),
49.8 (C7), 44.9 (C4), 41.8 (C1), 26.3 (C6).
19F NMR (282 MHz, CDCl3): d = –81.4 (3 F, m, CF3), –113.5 (1 F,
d, J = 251 Hz, SOCF2), –120.5 (1 F, d, SOCF2), –121.2 (2 F, m,
19F NMR (282 MHz, CDCl3): d = –107.5 (1 F, d, J = 233.9 Hz,
CF2), –112.5 (1 F, d, CF2).
Synthesis 2004, No. 14, 2297–2302 © Thieme Stuttgart · New York