Room temperature nucleophilic trifluoromethylthiolation of benzyl bromides with (bpy)Cu(SCF3)

Article abstract of DOI:10.1016/j.tet.2013.05.073

The nucleophilic trifluoromethylthiolation of benzyl bromides using (bpy)Cu(SCF₃) gave the desired products of benzyl trifluoromethyl sulfides in good to excellent yields. A diverse set of important functional groups including cyano, nitro, ester, alkoxy, halide, and heterocyclic groups can be well tolerated in the protocol.

Full text of DOI:10.1016/j.tet.2013.05.073

Tetrahedron 69 (2013) 6046e6050
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Tetrahedron
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Room temperature nucleophilic trifluoromethylthiolation of benzyl
bromides with (bpy)Cu(SCF3)
*
Dedao Kong, Zhou Jiang , Shaogang Xin, Zhengshuai Bai, Yaofeng Yuan,
*
Zhiqiang Weng
Department of Chemistry, Fuzhou University, Fujian 350108, China
a r t i c l e i n f o
a b s t r a c t
Article history:
The nucleophilic trifluoromethylthiolation of benzyl bromides using (bpy)Cu(SCF3) gave the desired
products of benzyl trifluoromethyl sulfides in good to excellent yields. A diverse set of important
functional groups including cyano, nitro, ester, alkoxy, halide, and heterocyclic groups can be well tol-
erated in the protocol.
Received 25 March 2013
Received in revised form 14 May 2013
Accepted 20 May 2013
Available online 23 May 2013
Ó 2013 Elsevier Ltd. All rights reserved.
Keywords:
Trifluoromethylthiolation
Benzyl bromides
Copper reagent
1. Introduction
(CuSCF3) is one of the most straightforward methods for the syn-
thesis of trifluoromethylthiolated compounds.9 Recently, we re-
The incorporation of fluorine-containing groups into organic
molecules is a powerful strategy in the process of drug design.1 This
escalating importance stems from the prevalence of fluorine-con-
taining substituents in many compounds that are of biological,
pharmaceutical, agricultural, and materials interest.
ported the synthesis of a series of copper(I) trifluoromethylthiolate
complexes ligated by bipyridine ligands for nucleophilic tri-
fluoromethylthiolation of aryl halides.10 These reactions provide
a novel and convenience approach for trifluoromethylthiolation of
aryl halides.
Among these substituents, the trifluoromethylthio group
(eSCF3) has attracted much attention by virtue of its strong
electron-withdrawing effect and high hydrophobicity parameter
In view of the likelihood of benzyl substituents acting as rigid
lipophilic groups in pharmacophore development,11 it would be of
interest to develop a transformation for the direct introduction of
a trifluoromethylthio group at the benzylic position. It is also
worthy of note that although a number of methods have been de-
veloped for synthesis of aryl trifluoromethyl thioethers, efficient
synthetic protocol able to prepare benzyl trifluoromethyl sulfides
are still rare. Examples have been reported involving reaction of
benzyl thiocyanate and (trifluoromethyl)trimethylsilane3f or the
reaction of benzyl halides with a trifluoromethyl sulfide anionic
salt.5e,12 However, in all of the cases, only unsubstituted benzyl
halides were employed. To date, a general method for synthesis of
various aryl-substituted benzyl trifluoromethyl sulfide mediated by
transition-metals under mild reaction conditions have not been
explored.
(
pR¼1.44).2 Accordingly, the synthesis of trifluoromethyl thioether
compounds is of great interest to synthetic chemists. A number of
synthetic methods exist to accomplish this transformation, e.g., the
nucleophilic,3 electrophilic,4 and radical5 trifluoromethylation of
disulfides, thiocyanates, thiols, and thiolates with
a
tri-
fluoromethylation reagent. However, these reactions are generally
limited by their need for the preparation of sulfur-precursors,
a narrow substrate scope, and a combination of high temperature.
The recent development of transition-metal-catalyzed tri-
fluoromethylthiolation provides a useful methodology for the
preparation of aryl trifluoromethyl thioethers in a single step with
readily available aryl halides,6 aryl boronic acids,7 and arenes.8 The
use of organometallic reagent, i.e., trifluoromethylthiocopper
As part of our continuing efforts in the development of copper-
mediated trifluoromethylation13 and trifluoromethylthiolation,10
we herein report a nucleophilic trifluoromethylthiolation of ben-
zyl bromides using (bpy)Cu(SCF3).
* Corresponding authors. E-mail address: zweng@fzu.edu.cn (Z. Weng).
0040-4020/$ e see front matter Ó 2013 Elsevier Ltd. All rights reserved.
http://dx.doi.org/10.1016/j.tet.2013.05.073

D. Kong et al. / Tetrahedron 69 (2013) 6046e6050
Table 2 (continued )
6047
2. Results and discussion
Entry
Benzyl bromides
Product
Yield (%)b
We began the exploration of trifluoromethylthiolation with
a model reaction between p-methylbenzyl bromide (1a) (1.5 equiv)
with (bpy)Cu(SCF3) (2) (1 equiv) (Table 1). To our delight this re-
action takes place and the desired product benzyl(trifluoromethyl)
sulfane (3a) was isolated in a moderate 66% after 8 h at 110 ꢀC in
toluene (Table 1, entry 1). To enable the efficiency of this trans-
formation, we examined various solvents and temperatures. The
reaction performed in THF at 80 ꢀC also resulted in a good yield
(75%, entry 2). On the contrary, using CH2Cl2, NMP, DMF, and DMSO
as solvent at room temperature or 80 ꢀC led to lower product yields
(entries 3, 7e9) and the reactions in a protic solvent, such as
methanol or ethanol furnished 3a in low yields (w10%) at 80 ꢀC
after 18 h (entries 5 and 6). By using diglyme and CH3CN as the
solvents, the trifluoromethylthiolation proceeded with excellent
yields of 3a at 80 ꢀC (91% and 98%, respectively; entries 4 and 10).
Further experiments revealed that a reaction at room temperature
in CH3CN after 12 h to give the desired 3a in 99% yield (entry 11).
5
6
98
96
7
8
95
96
9
96
95
10
Table 1
Optimization of the trifluoromethylthiolation of benzyl bromidesa
11
97
12
13
14
91
89
90
Entry
Solvent
T (ꢀC)
Time (h)
Yield (%)b
1
2
3
4
5
6
7
8
Toluene
THF
CH2Cl2
Diglyme
MeOH
EtOH
NMP
DMF
DMSO
CH3CN
CH3CN
110
80
rt
8
24
24
12
18
18
12
12
12
10
12
66
75
54
91
10
10
61
39
60
98
99
80
80
80
80
80
80
80
rt
9
10
11
15
97
a
Reaction conditions: 1a (0.038 mmol), 2 (0.025 mmol), solvent (1.0 mL), under
N2 atmosphere.
b
a
Yield were determined by the 19F NMR analysis of the crude reaction mixture
Reaction conditions: benzyl bromides (0.17 mmol), 2 (0.25 mmol), MeCN
with an internal standard.
(1.0 mL), rt, 8 h.
b
Isolation yield.
With the preliminary results in hand, the scope of tri-
fluoromethylthiolation of benzyl bromides was investigated under
the optimized conditions, and the results are shown in Table 2.
Under these conditions, the reaction proceeded very smoothly
and appears to tolerate a wide range of functionalized benzyl
bromides, including those containing alkyl, phenyl, cyano, nitro,
ester, alkoxy, halide, and heterocyclic groups.
The reaction of electron-neutral benzyl bromides 1aed and 2-
naphthylmethyl bromide 1e with 2 furnished the respective ben-
zyl trifluoromethyl sulfides 3aee in excellent yields (89e98%; en-
tries 1e5). Facile transformations of bromides 1fek containing
electron-withdrawing groups on the aromatic ring gave the cor-
responding trifluoromethylthiolated products in excellent yields
again (95e97%; entries 6e11). Substrates bearing electron-
donating groups, such as 3-methoxybenzyl bromide 1l also affor-
ded the desired product 3l in a good yield (91%, entry 12). It is
noteworthy that a chloro- and fluoro-substituent on the aromatic
ring of the benzyl bromides were tolerated under reaction condi-
tions and afforded the products in 89% and 90% yields, respectively
(entries 13 and 14). The heterocyclic functional groups were also
compatible with the reaction conditions and produced the desired
product in 97% yield (entry 15).
Table 2
Trifluoromethylthiolation of benzyl bromides by (bpy)Cu(SCF3)a
Entry
1
Benzyl bromides
Product
Yield (%)b
95
2
3
4
96
89
97
The high efficiency of the trifluoromethylthiolation described
above prompted us to extend the application to more complex
organic molecules. 4-Bromomethyl-7-methoxycoumarin (1p), one
of coumarin derivatives, was chosen to evaluate the late-stage

6048
D. Kong et al. / Tetrahedron 69 (2013) 6046e6050
trifluoromethylthiolation of biologically active molecules.14 Under
identical conditions as described in Table 2, the reaction of 1p with
2 led to the isolation of 4-trifluoroethylthio-7-methoxycoumarin
(3p) in 98% yield (Eq. 1).
1146,1116, 817, 756 cmꢂ1. GCeMS m/z 206 (Mþ). HRMS (EI) calcd for
C9H9SF3: 206.0377; Found: 206.0378.
4.2.2. (3-Methylbenzyl)(trifluoromethyl)sulfane (3b). Following the
general procedure and workup, 3b was isolated as an orange-red oil
(34 mg, 96% yield). Rf (25% EtOAc/hexane) 0.35. 1H NMR (400 MHz,
CDCl3)
(101 MHz, CDCl3)
d
7.18e7.03 (m, 4H), 4.01 (s, 2H), 2.28 (s, 3H); 13C NMR
d
138.6, 134.8, 129.6, 128.7 (d, J¼3.6 Hz), 127.6 (q,
ð1Þ
J¼307.3 Hz),125.9, 34.2 (q, J¼2.4 Hz), 21.2; 19F NMR (376 MHz, CDCl3)
d
ꢂ41.72 (s). IR (KBr): 2957, 2924, 2854, 1689, 1609, 1451, 1377, 1261,
1114, 1029, 911, 870, 799, 740, 693 cmꢂ1. GCeMS m/z 206 (Mþ).
HRMS (EI) calcd for C9H9SF3: 206.0377; Found: 206.0378.
4.2.3. Benzyl(trifluoromethyl)sulfane (3c).12c Following the general
procedure and workup, 3c was isolated as an orange-red oil (29 mg,
89% yield). Rf (25% EtOAc/hexane) 0.37. 1H NMR (400 MHz, CDCl3)
3. Conclusions
In summary, we have successfully employed a copper reagent for
nucleophilic trifluoromethylthiolation of benzyl bromides. This re-
action provides an efficient and convenient access to benzyl tri-
fluoromethyl sulfides. Cyano, nitro, ester, alkoxy, halide, and
heterocyclic functional groups were compatible with the reaction
conditions. Further investigations of related trifluoromethy
lthiolation are in progress.
d
7.27e7.20 (m, 5H), 4.04 (s, 2H); 13C NMR (101 MHz, CDCl3)
d 134.0,
128.0, 127.8, 126.9, 33.2 (q, J¼2.6 Hz); 19F NMR (376 MHz, CDCl3)
d
ꢂ41.65 (s). IR (KBr): 2961, 2925, 2854, 1512, 1456, 1377, 1261, 1104,
1023, 869, 802, 755, 698 cmꢂ1. GCeMS m/z 192 (Mþ).
4.2.4. (Biphenyl-3-ylmethyl)(trifluoromethyl)sulfane (3d). Following
the general procedure and workup, 3d was isolated as a white solid
(44 mg, 97% yield): mp 58e60 ꢀC. Rf (4% Et2O/pentane) 0.40. 1H
4. Experimental
NMR (400 MHz, CDCl3)
d
7.50e7.40 (m, 4H), 7.37e7.20 (m, 5H), 4.07
140.9, 139.5, 134.4, 129.62 (q,
(s, 2H); 13C NMR (101 MHz, CDCl3)
d
4.1. General experimental
J¼307.0 Hz), 128.2, 127.8, 126.7, 126.5, 126.1, 125.8, 33.2 (q,
1H NMR, 19F NMR, and 13C NMR spectra were recorded using
Bruker AVIII 400 or AVIII 500 spectrometer. 1H NMR and 13C NMR
chemical shifts were reported in parts per million (ppm) down-
field from tetramethylsilane and 19F NMR chemical shifts were
determined relative to CFCl3 as the external standard and low
field is positive. Coupling constants (J) are reported in Hertz (Hz).
The residual solvent peak was used as an internal reference: 1H
J¼2.4 Hz); 19F NMR (376 MHz, CDCl3)
d
ꢂ41.52 (s). IR (KBr): 3062,
3034, 2958, 2926, 1600, 1480, 1405, 1146, 1114, 1052, 757, 734,
698 cmꢂ1. GCeMS m/z 268 (Mþ). HRMS (EI) calcd for C14H11SF3:
268.0534; Found: 268.0532.
4.2.5. (Naphthalen-2-ylmethyl)(trifluoromethyl)sulfane (3e). Following
the general procedure and workup, 3e was isolated as an orange-red
oil (40 mg, 98% yield). Rf (4% Et2O/pentane) 0.43. 1H NMR (400 MHz,
NMR (chloroform
d d 77.0). The
7.26) and 13C NMR (chloroform
d
7.74e7.68 (m, 4H), 7.40e7.34 (m, 3H), 4.18 (s, 2H); 13C NMR
following abbreviations were used to explain the multiplicities:
s¼singlet, d¼doublet, t¼triplet, q¼quartet, m¼multiplet,
br¼broad. (bpy)Cu(SCF3) was prepared according to the
published procedures.10 Other reagents were received from
commercial sources. Solvents were freshly dried and degassed
according to the purification handbook Purification of Laboratory
Chemicals prior to use. Column chromatography purifications
were performed by flash chromatography using Merck silica
gel 60.
CDCl3)
(101 MHz, CDCl3)
d
132.2, 131.8, 131.3, 131.1, 129.6 (q, J¼307.1 Hz), 128.1,
127.7, 126.8, 126.7 (d, J¼3.0 Hz), 125.4 (d, J¼2.3 Hz), 125.3, 33.5 (q,
J¼2.4 Hz); 19F NMR (376 MHz, CDCl3)
d
ꢂ41.46 (s). IR (KBr): 3058,
2925, 2855, 1599, 1509, 1439, 1364, 1212, 1107, 954, 867, 827, 753,
476 cmꢂ1. GCeMS m/z 242 (Mþ). HRMS (EI) calcd for C12H9SF3:
242.0377; Found: 242.0379.
4.2.6. 2-((Trifluoromethylthio)methyl)benzonitrile (3f). Following th
e general procedure and workup, 3f was isolated as an orange-red oil
(35 mg, 96% yield). Rf (10% Et2O/pentane) 0.28. 1H NMR (400 MHz,
4.2. General procedure for trifluoromethylthiolation of ben-
zyl bromides with (bpy)Cu(SCF3)
CDCl3)
d
7.61 (d, J¼7.7 Hz,1H), 7.53 (t, J¼7.7 Hz,1H), 7.45 (d, J¼7.7 Hz,
1H), 7.36 (t, J¼7.7 Hz, 1H), 4.22 (s, 2H); 13C NMR (101 MHz, CDCl3)
Benzyl bromide
1
(0.17 mmol), [(bpy)Cu(SCF3)] (80 mg,
d
138.4, 132.2, 132.1, 129.3 (q, J¼307.4 Hz), 129.2e129.1 (m), 127.6,
0.25 mmol, 1.5 equiv), and CH3CN (1.0 mL) were added to a reaction
tube equipped with a stir bar. The mixture was stirred at room
temperature for 8e24 h until the reaction was judged complete by
TLC analysis. The reaction mixture was filtered through a pad of
Celite. The filtrate was added water (3ꢁ10 mL) at 0 ꢀC. The resulting
mixture was extracted with Et2O (3ꢁ15 mL), and the combined
organic layers was washed with water, and then dried over MgSO4.
The solvent was removed to give the desired product 3 without
further purification.
115.8, 111.6, 31.3 (q, J¼2.6 Hz); 19F NMR (376 MHz, CDCl3)
d
ꢂ41.22
(s). IR (KBr): 2958, 2926, 2854, 2228, 1600, 1488, 1451, 1259, 1153,
1113, 958, 869, 757, 678 cmꢂ1. GCeMS m/z 217 (Mþ). HRMS (EI) calcd
for C9H6SF3N: 217.0173; Found: 217.0174.
4.2.7. 4-((Trifluoromethylthio)methyl)benzonitrile (3g). Following the
general procedure and workup, 3g was isolated as an orange-red oil
(35 mg, 95% yield). Rf (10% Et2O/pentane) 0.25. 1H NMR (400 MHz,
CDCl3)
d
7.56 (d, J¼8.3 Hz, 2H), 7.38 (d, J¼8.3 Hz, 2H), 4.05 (s, 2H); 13
C
NMR (101 MHz, CDCl3)
d
139.9, 131.6, 129.3 (q, J¼307.3 Hz), 128.6,
4.2.1. (4-Methylbenzyl)(trifluoromethyl)sulfane (3a). Following the
general procedure and workup, 3a was isolated as an orange-red oil
(33 mg, 95% yield). Rf (25% EtOAc/hexane) 0.38. 1H NMR (400 MHz,
117.3, 111.0, 32.8 (q, J¼2.5 Hz); 19F NMR (376 MHz, CDCl3)
d
ꢂ41.34
(s). IR (KBr): 2961, 2926, 2853, 2231, 1609, 1504, 1415, 1148, 1116,
1021, 827, 757, 550 cmꢂ1. GCeMS m/z 217 (Mþ). HRMS (EI) calcd for
C9H6SF3N: 217.0173; Found: 217.0175.
CDCl3)
d
7.14 (d, J¼8.0 Hz, 2H), 7.06 (d, J¼8.0 Hz, 2H), 4.00 (s, 2H),
2.25 (s, 3H); 13C NMR (101 MHz, CDCl3)
d 136.8, 130.8, 129.6 (q,
J¼306.9 Hz), 128.5, 127.8, 33.0 (q, J¼2.4 Hz), 20.0; 19F NMR
4.2.8. (2-Nitrobenzyl)(trifluoromethyl)sulfane (3h). Following the ge
neral procedure and workup, 3h was isolated as an orange-red oil
(376 MHz, CDCl3)
d
ꢂ41.66 (s). IR (KBr): 2927, 2857,1515,1441,1258,

D. Kong et al. / Tetrahedron 69 (2013) 6046e6050
6049
(38 mg, 96% yield). Rf (4% Et2O/pentane) 0.20. 1H NMR (400 MHz,
CDCl3)
8.06 (d, J¼8.0 Hz, 1H), 7.60e7.51 (m, 1H), 7.44 (t, J¼8.0 Hz,
2H), 4.33 (s, 2H); 13C NMR (101 MHz, CDCl3)
146.7, 132.9, 131.6,
J¼307.6 Hz), 124.5 (d, J¼2.8 Hz), 115.8 (d, J¼22.2 Hz), 115.0 (d,
d
J¼21.2 Hz), 33.7 (q, J¼2.5 Hz); 19F NMR (376 MHz, CDCl3)
ꢂ41.57 (s),
d
d
ꢂ112.33 (s). IR (KBr): 2960, 2926, 2855, 1731, 1616, 1527, 1489, 1449,
1347, 1114, 946, 802, 749, 693 cmꢂ1. GCeMS m/z 210 (Mþ). HRMS (EI)
calcd for C8H6SF4: 210.0126; Found: 210.0127.
131.2 (d, J¼1.0 Hz), 129.8 (q, J¼307.1 Hz), 128.3, 124.7, 31.1 (q,
J¼2.5 Hz); 19F NMR (376 MHz, CDCl3)
d
ꢂ41.40 (s). IR (KBr): 2961,
2925, 2853, 1612, 1529, 1345, 1261, 1112, 788, 707 cmꢂ1. GCeMS m/z
237 (Mþ). HRMS (EI) calcd for C8H6SF3NO2: 237.0071; Found:
237.0078.
4.2.15. 5-Chloro-3-((trifluoromethylthio)methyl)benzo[b]thiophene
(3o). Following the general procedure and workup, 3o was isolated as
an orange-red oil (47 mg, 97% yield). Rf (2% Et2O/pentane) 0.25. 1H
4.2.9. (3-Nitrobenzyl)(trifluoromethyl)sulfane (3i). Following the ge
neral procedure and workup, 3i was isolated as an orange-red oil
(38 mg, 96% yield). Rf (5% Et2O/pentane) 0.25. 1H NMR (400 MHz,
NMR (400 MHz, CDCl3)
d
7.68 (d, J¼8.4 Hz, 2H), 7.39 (s, 1H), 7.27 (dd,
J¼8.4,1.5 Hz,1H), 4.24 (s, 2H); 13C NMR (101 MHz, CDCl3)
d 137.6, 137.5,
129.9, 129.4 (q, J¼307.2 Hz), 127.4, 126.8 (d, J¼0.6 Hz), 124.3, 123.0,
CDCl3)
d
8.16 (t, J¼1.8 Hz, 1H), 8.12e8.09 (m, 1H), 7.63 (d, J¼7.7 Hz,
120.2, 26.3 (q, J¼2.8 Hz); 19F NMR (376 MHz, CDCl3)
d
ꢂ41.56 (s). IR
1H), 7.48 (t, J¼3.8 Hz, 1H), 4.13 (s, 2H); 13C NMR (101 MHz, CDCl3)
(KBr): 2958, 2926, 2854, 1588, 1518, 1423, 1259, 1112, 1078, 862, 835,
795, 757 cmꢂ1. GCeMS m/z 282 (Mþ). HRMS (EI) calcd for C10H6S2F3Cl:
281.9552; Found: 281.9555.
d
147.5, 136.7, 133.8, 129.2 (q, J¼307.3 Hz), 128.9, 122.7, 122.0, 32.4 (q,
J¼2.6 Hz); 19F NMR (376 MHz, CDCl3)
d
ꢂ41.30 (s). IR (KBr): 2960,
2926, 2854, 1532,1353, 1317, 1260,1150, 1113, 906, 862, 811, 756, 719,
680 cmꢂ1. GCeMS m/z 237 (Mþ). HRMS (EI) calcd for C8H6SF3NO2:
237.0071; Found: 237.0073.
4.2.16. 4-Trifluoroethylthio-7-methoxycoumarin (3p). Following the
general procedure and workup, 3p was isolated as a bright yellow
solid (46 mg, 98% yield): mp 109e111 ꢀC. Rf (50% Et2O/hexane) 0.35.
4.2.10. (4-Nitrobenzyl)(trifluoromethyl)sulfane (3j). Following the ge
neral procedure and workup, 3j was isolated as an orange-red oil
(38 mg, 95% yield). Rf (5% Et2O/pentane) 0.23. 1H NMR (400 MHz,
1H NMR (400 MHz, CDCl3)
d
7.49 (d, J¼8.6 Hz, 2H), 7.16e6.62 (m,
2H), 6.37 (s,1H), 4.16 (s, 2H), 3.89 (s, 3H); 13C NMR (101 MHz, CDCl3)
d
162.1, 159.4, 154.7, 147.7, 129.0 (q, J¼307.5 Hz), 124.5, 123.9, 111.9
CDCl3)
d
8.22 (d, J¼8.5 Hz, 2H), 7.54 (d, J¼8.5 Hz, 2H), 4.18 (s, 2H); 13
C
(d, J¼50.0 Hz), 109.9, 100.3, 54.8, 29.0 (q, J¼2.6 Hz); 19F NMR
NMR (101 MHz, CDCl3)
d
146.6, 141.9, 129.2 (q, J¼307.4 Hz), 128.7,
(376 MHz, CDCl3)
d
ꢂ41.41 (s). IR (KBr): 2942, 1716, 1608, 1557, 1516,
123.0, 32.5 (q, J¼2.6 Hz); 19F NMR (376 MHz, CDCl3)
d
ꢂ41.31 (s). IR
1460, 1448, 1425, 1398, 1379, 1350, 1291, 1270, 1209, 1171, 1155,
1135, 1124, 1104, 1057, 1023, 989, 901, 865, 847, 822, 760, 721,
703 cmꢂ1. GCeMS m/z 290 (Mþ). HRMS (EI) calcd for C12H9F3O3S:
290.0224; Found: 290.0227.
(KBr): 2960, 2927, 2856,1711,1608,1524,1494,1348,1148,1115,1016,
859, 802, 756, 708 cmꢂ1. GCeMS m/z 237 (Mþ). HRMS (EI) calcd for
C8H6SF3NO2: 237.0071; Found: 237.0072.
4.2.11. Methyl 4-((trifluoromethylthio)methyl)benzoate (3k). Followi
ng the general procedure and workup, 3k was isolated as an orange-
red oil (41 mg, 97% yield). Rf (10% Et2O/pentane) 0.33. 1H NMR
Acknowledgements
We acknowledge the financial support from National Natural
Science Foundation of China (21072030) and Fuzhou University
(022318).
(400 MHz, CDCl3)
d
7.94 (d, J¼8.1 Hz, 2H), 7.34 (d, J¼8.1 Hz, 2H), 4.06
(s, 2H), 3.84 (s, 3H); 13C NMR (101 MHz, CDCl3)
d 165.5, 139.4, 129.4
(q, J¼307.1 Hz), 129.1, 128.8, 127.8, 51.1, 32.9 (q, J¼2.5 Hz); 19F NMR
(376 MHz, CDCl3)
d
ꢂ41.51 (s). IR (KBr): 2956, 2928, 2852, 1724, 1613,
1437, 1415, 1284, 1181, 1112, 1020, 798, 756, 713 cmꢂ1. GCeMS m/z
250 (Mþ). HRMS (EI) calcd for C10H9SF3O2: 250.0275; Found:
250.0276.
Supplementary data
Copies of NMR spectra for all products. Supplementary data
related to this article can be found in the online version, at http://
dx.doi.org/10.1016/j.tet.2013.05.073.
4.2.12. (3-Methoxybenzyl)(trifluoromethyl)sulfane (3l). Following the
general procedure and workup, 3l was isolated as an orange-red oil
(34 mg, 91% yield). Rf (pentane) 0.24. 1H NMR (400 MHz, CDCl3)
References and notes
d
7.26 (t, J¼7.9 Hz, 1H), 6.93e6.83 (m, 3H), 4.09 (s, 2H), 3.81 (s, 3H);
13C NMR (101 MHz, CDCl3)
d
159.9, 136.4, 130.6 (q, J¼306.9 Hz),129.9,
1. (a) Kirk, K. L. Org. Process Res. Dev. 2008, 12, 305e321; (b) Purser, S.; Moore, P. R.;
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2. Hansch, C.; Leo, A.; Taft, R. W. Chem. Rev. 1991, 91, 165e195.
121.1, 114.4, 113.5, 55.2, 34.2 (q, J¼2.5 Hz); 19F NMR (376 MHz, CDCl3)
€
d
ꢂ41.67 (s). IR (KBr): 2963, 2838, 1602, 1492, 1456, 1299, 1267, 1114,
1049, 919, 873, 791, 757, 737, 709, 690 cmꢂ1. GCeMS m/z 222 (Mþ).
HRMS (EI) calcd for C9H9SF3O: 222.0326; Found: 222.0327.
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4.2.13. (3-Chlorobenzyl)(trifluoromethyl)sulfane (3m). Following the
general procedure and workup, 3m was isolated as an orange-red oil
(34 mg, 89% yield). Rf (4% EtOAc/hexane) 0.31. 1H NMR (400 MHz,
CDCl3)
d
7.26e7.14 (m, 4H), 3.99 (s, 2H); 13C NMR (101 MHz, CDCl3)
d
135.3, 132.8, 128.6 (q, J¼307.1 Hz), 128.2, 127.1, 126.4, 125.2, 31.8 (q,
J¼2.5 Hz); 19F NMR (376 MHz, CDCl3)
d
ꢂ41.55 (s). IR (KBr): 2957,
5. (a) Wakselman, C.; Tordeux, M. J. Chem. Soc., Chem. Commun. 1984, 793e794; (b)
Wakselman, C.; Tordeux, M.; Clavel, J.-L.; Langlois, B. J. Chem. Soc., Chem. Commun.
1991, 993e994; (c) Koshechko, V. G.; Kiprianova, L. A.; Fileleeva, L. I. Tetrahedron
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2926, 2855, 1648, 1600, 1515, 1464, 1377, 1261, 1116, 880, 803,
756 cmꢂ1. GCeMS m/z 226 (Mþ). HRMS (EI) calcd for C8H6SF3:
225.9831; Found: 225.9836.
ꢀ
Langlois, B. R. J. Org. Chem. 1999, 64, 3813e3820; (f) Langlois, B.; Montegre, D.;
4.2.14. (3-Fluorobenzyl)(trifluoromethyl)sulfane (3n).15 Following the
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(32 mg, 90% yield). Rf (25% EtOAc/hexane) 0.28. 1H NMR (400 MHz,
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J. Chem. Soc., Perkin Trans. 11972, 2180e2182.
CDCl3)
164.1, 137.6 (dd, J¼7.7, 1.0 Hz), 130.4 (d, J¼8.4 Hz), 128.9 (q,
d
7.25e6.93 (m, 4H), 4.02 (s, 2H); 13C NMR (101 MHz, CDCl3)
d

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