1
O-(4-Methoxylcyclohexyl) S-methyl dithiocarbonate (19d).
90% yield; mixture (73 : 27) of cis- and trans-isomers; yellow
oil; spectral data for major isomer: 1H NMR (200 MHz,
CDCl3) d 1.2–2.1 (m, 8H), 2.51 (s, 3H), 3.25 (m, 1H), 3.32
(s, 3H), 5.59 (m, 1H); 13C NMR (50 MHz, CDCl3) d 18.5, 26.6,
27.1, 55.5, 75.6, 80.1, 214.7; spectral data for minor isomer: 1H
NMR (200 MHz, CDCl3) d 1.2–2.1 (m, 8H), 2.52 (s, 3H), 3.25
(m, 1H), 3.32 (s, 3H), 5.53 (m, 1H); 13C NMR (50 MHz,
CDCl3) d 18.7, 27.0, 27.5, 55.8, 76.4, 81.0, 214.9; IR (neat)
2940, 2863, 1045 cmꢀ1; MS (CI NH3) m/z 221 (100), 113 (86),
81 (48).
d ꢀ58.4 (s); H NMR (200 MHz, CDCl3) d 1.4–2.3 (m, 8H),
3.29 (s, 3H), 4.28 (m, 1H); 13C NMR (50 MHz, CDCl3) d 26.7,
27.9, 55.5, 75.2, 75.6 (q, JC–F = 2.1 Hz), 121.7 (q, JC–F
3
1
=
252 Hz); spectral data for minor isomer: 19F NMR (188 MHz,
CDCl3) d ꢀ58.3 (s); 1H NMR (200 MHz, CDCl3) d 1.4–2.3 (m,
8H), 3.46 (s, 3H), 4.41 (m, 1H); 13C NMR (50 MHz, CDCl3) d
27.2, 28.5, 55.7, 75.8, 76.3, 121.7 (q, 1JC–F = 254 Hz); MS (EI)
m/z 198 (52), 166 (13), 81 (61), 71 (100); HR MS calc. for
C8H13O2F3: 198.0868. Found: 198.0869.
Acknowledgements
Oxidative desulfurisation–fluorination of dithiocarbonates 19:
general procedure. To a suspension of 1,3-dibromo-5,5-di-
methylhydantoin (75 mmol) in dichloromethane (50 mL)
successively were added dropwise at ꢀ78 1C pyridine (6.75
mL) and 70% HF ꢂ py (15 mL). The mixture was stirred for 10
min at room temperature and cooled to 0 1C. A solution of
dithiocarbonate 19 (15 mL) in dichloromethane (50 mL) was
added dropwise. The resulting mixture was stirred for 1 h at
0 1C, carefully poured into an iced aqueous NaHCO3 solution,
neutralised with aqueous sodium hydroxide and extracted
with dichloromethane three times. The combined organic
phase was washed successively with aqueous hydrochloric acid
(1%), aqueous NaHSO3 and brine, and dried over magnesium
sulfate. The solvent was removed by distillation under atmo-
spheric pressure. The residue was then purified by distillation
‘‘bulb to bulb’’ (20 mmHg).
We would like to thank the English readers M. Popkin and
K. Wright for their helpful assistance about the manuscript.
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3
(200 MHz, CDCl3) d 1.2–2.0 (m, 10H), 4.21 (t, 1H, JH
ax–Hax
= 3.7 Hz); 13C NMR (50 MHz, CDCl3) d
= 9.0 Hz, 3JH
ax–Heq
23.4, 25.0, 32.4, 77.6, 121.7 (q, 1JC–F = 253 Hz); MS (CI CH4)
m/z 167 (44), 125 (100).
4-Methyl-1-trifluoromethoxycyclohexane (5b). 11% yield;
mixture (68 : 32) of cis- and trans-isomers; colourless oil;
spectral data for major isomer: 19F NMR (188 MHz, CDCl3)
d ꢀ58.2 (s); 1H NMR (200 MHz, CDCl3) d 0.97 (d, 3H, 3JH–H
= 6.0 Hz), 1.0–2.0 (m, 9H), 4.35 (m, 1H); spectral data for
1
minor isomer: 19F NMR (188 MHz, CDCl3) d ꢀ58.0 (s); H
NMR (200 MHz, CDCl3) d 0.94 (d, 3H, 3JH–H = 6.0 Hz), 1.0–
2.0 (m, 9H); MS (CI CH4) m/z 132 (97), 113 (100).
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49.
4-Isopropyl-1-trifluoromethoxycyclohexane (5c). 14% yield;
mixture (84 : 16) of cis- and trans-isomers; colourless oil;
spectral data for major isomer: 19F NMR (188 MHz, CDCl3)
d ꢀ58.2 (s); 1H NMR (200 MHz, CDCl3) d 0.89 (d, 6H, 3JH–H
= 6.8 Hz), 1.0–2.0 (m, 10H), 4.34 (m, 1H); 13C NMR
(50 MHz, CDCl3) d 19.8, 23.6, 30.8, 32.3, 42.9, 75.1, 121.8
(q, 1JC–F = 252 Hz); spectral data for minor isomer: 19F NMR
(188 MHz, CDCl3) d ꢀ58.0 (s); 1H NMR (200 MHz, CDCl3)
3
d 0.87 (d, 3H, JH–H = 6.7 Hz), 1.0–2.0 (m, 10H), 3.97
(m, 1H); 13C NMR (50 MHz, CDCl3) d 19.8, 27.5, 32.4,
32.6, 42.6, 78.6, 121.8 (q, JC–F = 252 Hz); MS (CI CH4)
1
m/z 209 (7), 225 (100).
4-Methoxy-1-trifluoromethoxycyclohexane (5d). 19% yield;
mixture (82 : 12) of cis- and trans-isomers; colourless oil;
spectral data for major isomer: 19F NMR (188 MHz, CDCl3)
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–Eur. J., 2003, 9, 1360; (c) F. Taddei and E. Kleinpeter, J. Mol.
ꢁc
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456 | New J. Chem., 2006, 30, 447–457