References and Notes
<A NAME="RG13710ST-1">1</A>
Hansch C.
Leo A.
Taft RW.
Chem.
Rev.
1991,
91:
165
<A NAME="RG13710ST-2">2</A>
Knunyants IN.
Rozhkov IN.
Alexandrov AM.
Yagupolskii LM.
J.
Gen. Chem. USSR (Engl. Transl.)
1967,
37:
1210
<A NAME="RG13710ST-3A">3a</A>
Magnier E.
Tordeux M.
Goumont R.
Magder K.
Wakselman C.
J. Fluorine Chem.
2003,
124:
55
<A NAME="RG13710ST-3B">3b</A>
Moïse J.
Goumont R.
Magnier E.
Wakselman C.
Synthesis
2004,
2297
<A NAME="RG13710ST-4">4</A>
Magnier-Bouvier C.
Blazejewski J.-C.
Larpent C.
Magnier E.
Tetrahedron Lett.
2006,
47:
9121
<A NAME="RG13710ST-5">5</A>
de Castries A.
Magnier E.
Monmotton S.
Fensterbank H.
Larpent C.
Eur.
J. Org. Chem.
2006,
4685
<A NAME="RG13710ST-6">6</A>
2-[(Trifluoromethyl)thio]ethanol
(5)
Reaction was carried out in the three-neck flask
equipped by condenser (-80 ˚C), mechanical
stirrer, and bubbler. To the stirred suspension of sodium sulfite
(113.5 g, 0.9 mol) and sodium formate (93.6 g, 0.9 mol) in DMF-H2O
(600 mL:180 mL) mixture mercaptoethanol (70 g, 0.9 mol) in DMF (100 mL)
was added in a single portion at 0 ˚C under argon.
CF3I (216 g, 1.1 mol) was bubbled into the reaction mixture
for 2-3 h at r.t. After stirring at r.t. for 24 h the solution
was poured into H2O (300 mL). Product was extracted by
Et2O (5 × 300 mL), organic
layer was washed by diluted HCl (3 × 50
mL), H2O (5 × 200 mL) and
dried (MgSO4). Solvent was removed by distillation at
atmospheric pressure, and product was purified by distillation.
Yield 90 g, 68%; bp 124-126 ˚C. ¹H NMR
(299.5 MHz, DMSO-d
6): δ = 3.06
(t, ³
J = 6.2
Hz, 2 H, CH2), 3.64 (t, ³
J = 6.2 Hz,
2 H, CH2), 5.01-5.35 (br s, 1 H, OH). ¹9F
NMR (282.2 MHz, DMSO-d
6): δ = -39.96
(s, SCF3). Anal. Calcd for C3H5F3OS:
C, 24.66; H, 3.45; S, 21.94. Found: C, 24.87; H, 3.40; S, 22.03.
<A NAME="RG13710ST-7">7</A>
2-Chloroethyl Trifluoromethyl
Sulfide (6)
SOCl2 (25 mL, 0.33 mol) was
added dropwise to the alcohol 5 (45 g,
0.31 mol) at 0 ˚C over 30 min. The reaction mixture was
stirred under reflux for 2 h. After cooling to r.t. H2O
(0.3 mL), followed by K2CO3 (2 g), was added,
and the resulting mixture was allowed to stand overnight. Product 6 was purified by vacuum distillation (6.7˙10-5 bar)
over K2CO3 into cooled trap and following
distillation at atmospheric pressure. Yield 49 g, 96%;
bp 94-96 ˚C. ¹H NMR (299.5 MHz,
CDCl3): δ = 3.21
(t, ³
J = 7.5
Hz, 2 H, CH2), 3.72 (t, ³
J = 7.5 Hz,
2 H, CH2). ¹9F NMR (282.2 MHz, DMSO-d
6): δ = -41.38
(s, SCF3). ¹³C NMR (125.8
MHz, CDCl3): δ = 31.8
(q, ³
J
CF = 2.5
Hz, α-CH2), 42.2 (s, β-CH2),
130.7 (q, ¹
J
CF = 306.9
Hz, CF3).
<A NAME="RG13710ST-8">8</A>
Oxidation of Sulfide
6 to Sulfoxide 7 Using Oxone
®
To
the stirred mixture (mechanical stirrer) of SiO2 (340
g) and H2O (135 mL) Oxone® (125 g,
0.41 mol of KHSO5) and a solution of sulfide 6 (45 g, 0.27 mol) in CH2Cl2 (700
mL) were added in a single portion. The reaction mixture was stirred
at r.t. for 120 h (monitoring by ¹9F NMR). Silica
gel was filtered off and washed with CH2Cl2 (ca
300 mL). The organic layer was washed with a FeSO4 solution,
dried (MgSO4), and filtered. Solvent was removed at atmospheric pressure,
and product was purified by distillation. Yield 47 g, 96%;
bp 64 ˚C (9.3˙10-³ bar). ¹H
NMR (299.5 MHz, CDCl3): δ = 3.17-3.27
(m, 1 H, CH2), 3.44-3.51 (m, 1 H, CH2),
3.88-4.06 (m, 2 H, CH2). ¹9F
NMR (282.2 MHz, CDCl3): δ = -74.15
(s, SOCF3). ¹³C NMR (125.8
MHz, CDCl3): δ = 35.5
(s, β-CH2), 51.4 (q, ³
J
CF = 2.5
Hz, α-CH2), 125.4 (q, ¹
J
CF = 333.3
Hz, CF3).
<A NAME="RG13710ST-9">9</A>
Harris JF.
J. Org. Chem.
1967,
32:
2063
