Oxidation of Sulfur-Containing Compounds with HOF‚CH3CN
J . Org. Chem., Vol. 62, No. 5, 1997 1461
e) 502 (M)+, 155. Anal. Calcd for C15H11F13O2S: C, 35.87; H,
2.21. Found: C, 35.94, H, 2.09.
Meth yl p-n itr op h en yl su lfon e (6)29 was obtained in 90%
yield, mp 142 °C. IR: 1320, 1154 cm-1
.
1H NMR: 6.3 (4H,
AB, J ) 8.1 Hz), 3.13 (3H, s). MS: (m/ e) 201 (M)+.
Bu tyl su lfon e (10), which is commercially available, was
obtained in 75% yield, mp 45 °C.
Meth yl ter t-bu tyl su lfon e (11)30 was obtained in 75%
yield, mp 83 °C. IR: 1285, 1117 cm-1
1.44 (3H, s).
.
1H NMR: 2.63 (3H, s),
ter t-Bu tyl su lfon e (12)31 was obtained in 95% yield, mp
130 °C. IR: 1269, 1088 cm-1 1H NMR: 1.45 (s). MS: (m/ e)
.
121 (M - t-Bu)+.
2-Meth yl-1,3-d ith ia n e S,S,S,S-tetr a oxid e (14)32 was ob-
tained in 95% yield, mp 258 °C. IR: 1326, 1150 cm-1
.
1H
NMR: (in DMSO-d6) 5.13 (1H, q, J ) 7 Hz), 3.48 (4H, m), 2.41
(1H, m), 2.07 (1H, m), 1.51 (3H, d, J ) 7 Hz). MS: (m/ e) 198
(M)+, 134.
F u r fu r yl su lfon e (20) was obtained in 85% yield, mp 72
°C. IR: 1313, 1153 cm-1 1H NMR: 7.5 (2H, d, J ) 1.5 Hz),
.
6.57 (2H, d, J ) 3.2 Hz), 6.44 (2H, dd, J 1 ) 3.2, J 2 ) 1.5 Hz),
4.32 (4H, s). MS: (m/ e) 162 (M - SO2), 81. Anal. Calcd for
C10H10O4S: C, 53.09; H, 4.46. Found: C, 52.91; H, 4.34.
Th ioch r om a n -4-ol S,S-d ioxid e (22)18 was obtained in 95%
yield, mp 93 °C. 1H NMR: 7.82-7.45 (4H, m), 4.85 (1H, dd,
J 1 ) 6, J 2 ) 4 Hz), 3.63 (1H, dt, J 1 ) 10, J 2 ) 4 Hz), 3.23 (2H,
m), 2.63 (1H, m), 2.45 (1H, m). MS: (m/ e) 198 (M)+.
Allyl su lfon e (24)19 was obtained in 86% yield, oil. 1H
NMR: 5.9 (2H, m), 5.4 (4H, m), 3.72 (4H, d, J ) 7 Hz). MS:
(m/ e) 146 (M)+, 41.
Gen er a l P r oced u r e for Wor k in g w ith F lu or in e. Fluo-
rine is a strong oxidizer and a very corrosive material. An
appropriate vacuum line made from copper or monel in a well
ventilated area should be constructed for working with this
element. For more experimental details see reference.27 For
the occasional user, however, various premixed mixtures of
F2 in inert gases are commercially available, simplifying the
whole process. The reactions themselves can be carried out
in glass vessels. If elementary precautions are taken, work
with fluorine is relatively simple and we have had no bad
experiences working with it.
2,3-Ep oxyp r op yl su lfon e (25) was obtained in 70% yield,
oil. IR: 1310, 1128 cm-1
.
1H NMR: 3.4 (4H, m), 3.25 (2H,
Gen er a l P r oced u r e for P r od u cin g th e Oxid izin g HOF‚
CH3CN. Mixtures of about 10% F2 with nitrogen were used
in this work. The gas mixture was prepared in a secondary
container before the reaction was started. This mixture was
then passed at a rate of about 400 mL/min through a cold (-15
°C) mixture of 400 mL of CH3CN and 40 mL of H2O. The
formation of the oxidizing reagent was monitored by reacting
aliquots with an acidic aqueous solution of KI. The liberated
iodine was titrated with thiosulfate. Concentrations of 0.2-
0.3 mol/liter were routinely achieved. When working in small
scale it is possible to achieve concentrations of more than 1.0
mol/L, and the solution has a half-life time of 3-4 h at rt.
Gen er a l Oxid a tion P r oced u r es. Sulfides: About 8 mmol
of a sulfide was dissolved in 10 mL of CHCl3 at 0 °C and added
to about 20 mmol (50% excess) of a cold (-5 °C to 0 °C) aqueous
CH3CN solution of HOF‚CH3CN in one portion. The oxidizing
power was usually lost after 5-10 min. The reaction mixture
was then neutralized with saturated sodium bicarbonate
solution, extracted with CH2Cl2, and washed again with
NaHCO3 and water until neutral. The organic layer was dried
over MgSO4, the solvent evaporated, and the sulfone isolated
and purified by either recrystallization from EtOH or short
chromatography. Known products were compared with either
an authentic sample or with spectral properties reported in
the literature. An excellent agreement was always found. We
report here the appropriate analytical data only for new
compounds or for those not well defined in the literature.
1,1,2,2-Tetr a h yd r op er flu or ooctyl p-tolyl su lfid e (2) was
prepared according to reference 22 and obtained in 95% yield
as an oil. 1H NMR: 7.2 (4H, AB, J ) 8.1 Hz), 3.06 (2H, m),
2.37 (2H, m), 2.34 (3H, s). 19F NMR: -81.3 (3F, dt, J 1 ) 9, J 2
) 2 Hz), -114.7, -122.4, -123.4, -123.8, -126.7 (each 2F,
m). MS: (m/ e) 470 (M)+.
m), 2.96 (2H, t, J ) 4.5 Hz), 2.55 (2H, m). 13C NMR: 56.85
(CH2), 56.56 (CH2), 46.1 (2CH2), 45.6 (CH), 45.4 (CH).
A
mixture of two diastereoisomers. Anal. Calcd for C6H10O4S:
C, 40.44; H, 5.66; S, 17.99. Found: C, 39.82; H, 5.58;.S, 17.73
2,3-Dih yd r oxyp r op yl su lfon e (26) was obtained in 95%
yield (based on 25), oil. IR: 3462, 1310, 1128 cm-1
. Anal.
Calcd for C6H14O6S: C, 33.64; H, 6.59; S, 14.96. Found: C,
33.36; H, 5.94; S, 15.24.
Meth oxym eth yl p h en yl su lfon e (28)11 was obtained in
95% yield, mp 70 °C. IR: 1330, 1142 cm-1
.
1H NMR: 7.72
(5H, m), 4.52 (2H, s), 3.66 (3H, s). MS: (m/ e) 186 (M)+.
Ar yl P er flu or a lk yl Su lfid es. In general the starting
sulfides were prepared according to reference 22. About 2 g
of aryl mercaptan was dissolved in 40 mL of cold (+5 - +7
°C), dry benzene containing an equimolar amount of 1,8-
diazabicyclo[5.4.0]undec-7-ene (DBU). The reaction was stirred
under nitrogen for 10 min and subsequently treated with an
equimolar amount of the appropriate perfluoroalkyl iodide. The
reaction mixture was brought to room temperature and stirred
under nitrogen for 15 h. Pouring into water, extraction with
chloroform, drying the organic layer with MgSO4, and rotevap-
oration of the solvents afforded the desired sulfide in 60-70%
yield (after column chromatography), the rest being the
respective disulfide. The oxidation of these sulfides was
similar to that described above except that 10 mol equiv of
HOF‚CH3CN (fivefold excess) was used at room temperature
for 10-30 min.
P er flu or obu tyl p-tolyl su lfon e (31)10 was obtained in 95%
yield, oil. MS: (m/ e) 374 (M)+.
P er flu or ooctyl p-tolyl su lfon e (33)10 was obtained in 85%
yield, oil. MS: (m/ e) 574 (M)+.
p-Br om op h en yl p er flu or obu tyl su lfon e (35) was ob-
tained in 95% yield, mp 56 °C. IR: 1362, 1174 cm-1
.
1H
NMR: 7.86 (m). 19F NMR: -77.18 (3F, m), -106.3 (2F, t, J
) 13 Hz), -115.24 (2F, m), -120.16 (2F, m). MS: (m/ e) 440
(M)+. Anal. Calcd for C10H4BrF9O2S: C, 27.35; H, 0.92.
Found: C, 26.94; H, 1.28.
Meth yl p-tolyl su lfon e (4)28 was obtained in 100% yield,
mp 88 °C. IR: 1300, 1143 cm-1. MS: (m/ e) 170 (M)+.
1,1,2,2-Tetr a h yd r op er flu or ooctyl p-tolyl su lfid e (5) was
obtained in 100% yield, mp 92 °C. IR: 1317, 1150 cm-1 1H
.
NMR: 7.6 (4H, AB, J ) 8.1 Hz), 3.3 (2H, m), 2.62 (2H, m),
2.48 (3H, s). 19F NMR: -81.3 (3F, dt, J 1 ) 10, J 2 ) 2 Hz),
-114, -122.4, -123.4, -123.6, -126.7 (each 2F, m). MS: (m/
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3660.
(27) Hebel, D.; Rozen, S. J . Org. Chem. 1991, 56, 6298.
(28) Hyatt, J . A.; White, A. W. Synthesis 1984, 214.
(32) Autenrieth, W.; Wolff, K. Chem. Ber. 1899, 32, 1375.