Electrophilic substitution reactions using an electrogenerated ArS(ArSSAr)+ cation pool as an ArS+ equivalent

Article abstract of DOI:10.1016/j.tetlet.2012.01.131

Arylbis(arylthio)sulfonium ions (ArS(ArSSAr)⁺), which were generated and accumulated by the low-temperature electrolysis of diaryl disulfide (ArSSAr), were found to serve as ArS⁺ equivalent in electrophilic substitution reactions of

Full text of DOI:10.1016/j.tetlet.2012.01.131

Tetrahedron Letters 53 (2012) 1916–1919
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Tetrahedron Letters
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Electrophilic substitution reactions using an electrogenerated ArS(ArSSAr)+
cation pool as an ArS+ equivalent
Kouichi Matsumoto a, Yuki Kozuki a, Yosuke Ashikari c, Seiji Suga b, Shigenori Kashimura a,
Jun-ichi Yoshida c,
⇑
a Faculty of Science and Engineering, Kinki University, 3-4-1 Kowakae, Higashi-osaka, Osaka 577-8502, Japan
b Division of Chemistry and Biochemistry, Graduate School of Natural Science and Technology, Okayama University, 3-1-1 Tsushima-naka, Kita-ku, Okayama 700-8530, Japan
c Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto 615-8510, Japan
a r t i c l e i n f o
a b s t r a c t
Arylbis(arylthio)sulfonium ions (ArS(ArSSAr)+), which were generated and accumulated by the low-tem-
perature electrolysis of diaryl disulfide (ArSSAr), were found to serve as ArS+ equivalent in electrophilic
substitution reactions of aromatic compounds, enolizable ketones, enol acetates, ketene silyl acetals and
allylsilanes to give the corresponding arylthiolated products.
Article history:
Received 21 December 2011
Revised 29 January 2012
Accepted 31 January 2012
Available online 7 February 2012
Ó 2012 Elsevier Ltd. All rights reserved.
Keywords:
Sulfenium ion
Disulfide
Oxidation
Electrophilic substitution
Electrochemistry
Introduction
anode
ArSSAr
The arylthio (ArS) substituted organic compounds are widely
utilized in the organic synthesis, because of the easy generation
of carbanions adjacent to the sulfur atom and easy removal of
the ArS group.1 ArS-substituted compounds, especially aromatic
compounds have also received significant research interest in the
functional materials.2 Various methods for the synthesis of ArS-
substituted compounds have been developed so far. Among them,
the direct introduction of ArS group to the organic molecule is one
of the most straightforward methods. Arylsulfenium ions3 (ArS+)
seem to be suitable reagents for this purpose, because the reactions
of ArS+ with carbon nucleophiles should lead to the formation of
ArS-substituted organic compounds. A popular method to generate
ArS+ is heterolysis of ArS-X (X = halogen) using silver salts.4
However, the method suffers from the problems of instability of
ArS-X, high cost of silver salts, and wastes of silver halides.
Nu-
e
ArS SAr
SAr
''ArS+'' equivalent
ArS Nu
Scheme 1. The generation and accumulation of ArS(ArSSAr)+ cation pool and its
reactions with carbon nucleophiles (electrophilic substitution reactions).
ing the ArS group into alkenes and dienes, as well as generating
alkoxycarbenium ions from thioacetals.8,9 In this Letter, we report
that ArS(ArSSAr)+ cation pool serves as an effective reagent for
introducing the ArS group in electrophilic substitution reactions
of aromatic compounds, enolizable ketones, enol acetates, ketene
silyl acetals, and allylsilanes (Scheme 1).
Recently, we have revealed that highly reactive arylbis(aryl-
thio)sulfonium ions5 (ArS(ArSSAr)+) can readily be generated and
accumulated in the solution by the low-temperature electrochem-
ical oxidation6 of diaryl disulfide (ArSSAr)7 in CH2Cl2 using Bu4-
NBF4 or Bu4B(C6F5)4 as a supporting electrolyte. The ArS(ArSSAr)+
cation pool was found to serve as an effective reagent for introduc-
Results and discussion
We first focused on the reactions of ArS(ArSSAr)+ with aromatic
compounds. A typical procedure is as follows. In the first step, a
solution of ArS(ArSSAr)+BF4ꢀ (Ar = p-FC6H4) was generated and
accumulated by the anodic oxidation of ArSSAr (0.40 mmol) in
0.3 M Bu4NBF4/CH2Cl2 (8.0 mL) at ꢀ78 °C (0.67 F/mol). 0.67 F/mol
is the theoretical amount of electricity to convert ArSSAr
into ArS(ArSSAr)+. In the second step, 1,3,5-trimethoxybenzene
⇑
Corresponding author. Tel.: +81 75 383 2726; fax: +81 75 383 2725.
E-mail address: yoshida@sbchem.kyoto-u.ac.jp (J. Yoshida).
0040-4039/$ - see front matter Ó 2012 Elsevier Ltd. All rights reserved.
doi:10.1016/j.tetlet.2012.01.131

K. Matsumoto et al. / Tetrahedron Letters 53 (2012) 1916–1919
1917
(0.20 mꢀmol) was added to the anodic solution containing ArS(ArS-
SAr)+BF4 (ca. 0.27 mmol) at ꢀ78 °C, and the solution was stirred at
the same temperature for 3 min. Then, Et3N (1 mL) was added to
quench the reaction. The work-up followed by chromatography
gave 2-ArS-1,3,5-trimethoxybenzene in an 84% yield (Table 1,
entry 1). It is noteworthy that the reaction was completed within
3 min at ꢀ78 °C, indicating that ArS(ArSSAr)+ is highly reactive.10
The reactions with other aromatic compounds were examined.
As shown in Table 1, m-methoxytoluene and 3,5-dimethoxychloro-
benzene reacted with ArS(ArSSAr)+ quickly at ꢀ78 °C to give the
corresponding mono ArS-substituted products in high yields
(entries 2 and 3).
at all (entry 7). Enol acetate reacted with ArS(ArSSAr)+ to give
ArS-substituted compounds in a moderate yield (entry 8).
Next, reactions of ArS(ArSSAr)+ with silyl-substituted carbon
nucleophile such as ketene silyl acetal was examined. The reaction
of ArS(ArSSAr)+ with dimethylketene methyltrimethylsilylacetal
gave the corresponding ArS-substituted product in a good yield
(entry 9).
The effect of the counter anion is interesting. The reaction of
electrogenerated ArS(ArSSAr)+Xꢀ, which was prepared by the ano-
dic oxidation of ArSSAr (0.40 mmol) in Bu4N+Xꢀ/CH2Cl2, with 3-
(trimethylꢀsilyl)cyclohexene (1.00 mmol) was examined (Xꢀ = BF4ꢀ
or BðC6F5Þ ). The use of BFꢀ as Xꢀ, the reaction gave the allylated
4
4
Enolizable ketones also reacted with ArS(ArSSAr)+ and the ArS
product (0.28 mmol) quantitatively (Scheme 2).11 In contrast, the
group was introduced to the
a-carbon. The reaction of acetophe-
use of BðC6F5Þꢀ as Xꢀ led to the formation of the allylated product
4
none is interesting. ArS was introduced to the methyl carbon selec-
tively. The aromatic ring was not affected, presumably because of
electron-withdrawing effect of the carbonyl group (entry 4). Ethyl
phenyl ketone also reacted with ArS(ArSSAr)+ and ArS was intro-
in a 188% yield based on the electricity (0.506 mmol). Surprisingly,
the decrease in the amount of electricity (0.20 F/mol) led to the for-
mation of a significant amount of the allylated product (463% yield
based on the electricity, 0.370 mmol), indicating that a catalytic
amount of ArS(ArSSAr)+ is sufficient for the reaction.
duced to the a-carbon selectively, although the yield was moderate
(entry 5). 1,3-Dicarbonyl compounds such as acetylacetone reacted
with ArS(ArSSAr)+ and the ArS group was introduced into the
methylene carbon in a moderate yield (entry 6). In contrast, the
reaction of dimethyl malonate with ArS(ArSSAr)+ did not proceed
The following explanation seems to be reasonable (Scheme 3).
One mole of ArS(ArSSAr)+ reacted with the 3-(trimethylsilyl)cyclo-
hexene to generate one mole of the arylthiolated product, one mole
of ArSSAr, and one mole of Me3Si+BðC6F5Þꢀ. Me3Si+ BðC6F5Þꢀ reacted
4
4
Table 1
Reactions of ArS(ArSSAr)+ cation pool with carbon nucleophiles (Ar = p-FC6H4)a
Entry
Carbon nucleophile
Conditions
Product
% Yieldb
84
OMe
OMe
SAr
1
ꢀ78 °C, 3 min
MeO
MeO
OMe
MeO
ArS
OMe
2
3
ꢀ78 °C, 3 min
ꢀ78 °C, 3 min
90
OMe
Cl
OMe
SAr
Cl
Quant
OMe
MeO
OMe
SAr
O
O
O
O
4
5
6
7
0 °C, 24 h
0 °C, 24 h
0 °C, 24 h
0 °C, 24 h
96c
48c,d
46
O
O
SAr
O
O
SAr
O
O
O
O
n.d.
MeO
OMe
MeO
OMe
SAr
OAc
O
8
9
ꢀ78 °C, 3 min
ꢀ78 °C, 3 min
34
82
ArS
ArS
OSiMe3
OMe
O
OMe
a
A Typical procedure: ArSSAr (Ar = p-FC6H4, 0.40 mmol, 2 equiv) was oxidized electrochemically in 0.3 M Bu4NBF4/CH2Cl2 at ꢀ78 °C using
0.67 F/mol of electricity. The solution of ArS(ArSSAr)+BF4ꢀ (ca. 0.27 mmol) thus obtained was allowed to react with carbon nucleophile
(0.20 mmol). Then the reaction was quenched with Et3N (1 mL).
b
Isolated yield.
4.5 equiv of ArSSAr (Ar = p-FC6H4) was used.
The purity of the product was ca. 80%.
c
d

1918
K. Matsumoto et al. / Tetrahedron Letters 53 (2012) 1916–1919
SiMe3
References and notes
1. Cremlyn, R. J. An Introduction to Organosulfur Chemistry; John Wiley and Sons:
Chichester, 1996.
2. For example: Tsuchida, E.; Oyaizu, K. Bull. Chem. Soc. Jpn. 2003, 76, 15. and
references cited therein.
-e, 0.4Y mF
(Y F/mol)
ArS
ArS SAr
1.00 mmol
-78 oC
30 min
ArSSAr
(Ar = p-FC6H4)
SAr
-78 o
C
X-
Bu4N+X-/CH2Cl2
3. (a) Larsen, A. G.; Holm, A. H.; Roberson, M.; Daasbjerg, K. J. Am. Chem. Soc. 2001,
123, 1723; (b) Brinck, T.; Carlqvist, P.; Holm, A. H.; Daasbjerg, K. J. Phys. Chem. A
2002, 106, 8827; (c) Holm, A. H.; Yusta, L.; Carlqvist, P.; Brinck, T.; Daasbjerg, K.
J. Am. Chem. Soc. 2003, 123, 2148.
4. Smit, W. A.; Krimer, M. Z.; Vorob’eva, E. A. Tetrahedron Lett. 1975, 16, 2451.
5. For example: (a) Gybin, A. S.; Smit, W. A.; Bogdanov, V. S.; Krimer, M. Z.; Kalyan,
J. B. Tetrahedron Lett. 1980, 21, 383; (b) Bogdanov, V. S.; Gybin, A. S.;
Cherepanova, E. G.; Smit, W. A. Izv. Akad. Nauk SSSR Ser. Khim. 1981, 2681;
(c) Judek, M. W.; Spiewak, B. P. Polym. Degrad. Stab. 1995, 48, 131.
6. (a) Yoshida, J.; Kataoka, K.; Horcajada, R.; Nagaki, A. Chem. Rev. 2008, 108, 2265;
(b) Sperry, J. B.; Wright, D. L. Chem. Soc. Rev. 2006, 35, 605; (c) Lund, H. J.
Electrochem. Soc. 2002, 149, S21–S33; (d) Moeller, K. D. Tetrahedron 2000, 56,
9527.
7. (a) Bewick, A.; Coe, D. E.; Mellor, J. M.; Walton, D. J. J. Chem. Soc., Chem. Commun.
1980, 51; (b) Töteberg-Kaulen, S.; Steckhan, E. Tetrahedron 1988, 44, 4389;
Boryczka, S.; Elothmani, D.; Do, Q. T.; Simonet, J.; Le Guillanton, G. J.
Electrochem. Soc. 1996, 143, 4027; (d) Do, Q. T.; Elothmani, D.; Le Guillanton,
G. Tetrahedron Lett. 1998, 39, 4657; (e) Glass, R. S.; Jouikov, V. V. Tetrahedron
Lett. 1999, 40, 6357; (f) Do, Q. T.; Elothmani, D.; Simonet, J.; LeGuillanton, G.
Electrochim. Acta 2005, 50, 4792. and references cited therein.
0.40 mmol
ca. 0.40Y mmol then Et3N
-
X- = BF4
Y = 0.67
0.280 mmol
(quantitative yield
based on electricity)
-
X- = B(C6F5)4 Y = 0.67
0.506 mmol
(188% yield based
on electricity)
X- = B(C6F5)4
Y = 0.20
0.370 mmol
(463% yield based
on electricity)
-
Scheme 2. The reaction of electrogenerated ArS(ArSSAr)+Xꢀ with 3-(trimethyl-
silyl)cyclohexene (Ar = p-FC6H4).
8. (a) Matsumoto, K.; Suga, S.; Yoshida, J. Org. Biomol. Chem. 2011, 9, 2586; See
also: (b) Suga, S.; Matsumoto, K.; Ueoka, K.; Yoshida, J. J. Am. Chem. Soc. 2006,
128, 7710; (c) Matsumoto, K.; Fujie, S.; Ueoka, K.; Suga, S.; Yoshida, J. Angew.
Chem., Int. Ed. 2008, 47, 2506; (d) Matsumoto, K.; Ueoka, K.; Fujie, S.; Suga, S.;
Yoshida, J. Heterocycles 2008, 76, 1103; (e) Matsumoto, K.; Fujie, S.; Suga, S.;
Nokami, T.; Yoshida, J. Chem. Commun. 2009, 5448; (f) Matsumoto, K.; Ueoka,
K.; Suzuki, S.; Suga, S.; Yoshida, J. Tetrahedron 2009, 65, 10901; (g) Fujie, S.;
Matsumoto, K.; Suga, S.; Yoshida, J. Chem. Lett. 2009, 38, 1186; (h) Fujie, S.;
Matsumoto, K.; Suga, S.; Nokami, T.; Yoshida, J. Tetrahedron 2010, 66, 2823; (i)
Saito, K.; Ueoka, K.; Matsumoto, K.; Suga, S.; Nokami, T.; Yoshida, J. Angew.
Chem., Int. Ed. 2011, 50, 5153; (j) Saito, K.; Saigusa, Y.; Nokami, T.; Yoshida, J.
Chem. Lett. 2011, 40, 678.
9. Eelectrochemical oxidation of thioacetal to generate alkoxycarbenium ions: (a)
Yoshida, J.; Sugawara, M.; Kise, N. Tetrahedron Lett. 1996, 37, 3157; (b)
Sugawara, M.; Mori, K.; Yoshida, J. Electrochim. Acta 1997, 1995, 42; (c) Yoshida,
J.; Sugawara, M.; Tatsumi, M.; Kise, N. J. Org. Chem. 1998, 63, 5950; See also: (d)
Suzuki, S.; Matsumoto, K.; Kawamura, K.; Suga, S.; Yoshida, J. Org. Lett. 2004, 6,
3755.
ArS(ArSSAr)+
B(C6F5)4
-
ArS
Me3Si+
ArSSAr
+
+
-
B(C6F5)4
SiMe3
ArS+
B(C6F5)4
ArSSiMe3
+
-
Me3Si+
B(C6F5)4
ArS
+
SiMe3
-
Scheme 3. The reaction mechanism of ArS(ArSSAr)+BðC6F5Þ4ꢀ with 3-(trimethyl-
silyl)cyclohexene (Ar = p-FC6H4).
10. Reactivity of cations: (a) Mayr, H.; Ofial, A. R. Angew. Chem., Int. Ed. 2006, 45,
1844; (b) Hofmann, M.; Hampel, N.; Kanzian, T.; Mayr, H. Angew. Chem., Int. Ed.
2004, 43, 5402.
with ArSSAr to give ArS+BðC6F5Þꢀ and ArSSiMe3. The ArS+BðC6F5Þꢀ
11. In this case, the theoretical and quantitative amount of the allylated product is
0.268 mmol, because 0.4 mmol ꢁ 0.67 (F/mol) = 0.268 mmol.
4
4
12. BFꢀ4 is known to serves as nucleophile. See, Ref. 8c,i,9.
or its complex with ArSSiMe3 reacted with the allylsilane to give
one mole of the arylthiolated product, generating Me3Si+BðC6F5Þ4ꢀ,
which also can be used to activate ArSSAr. When BFꢀ4 was used
as the counter anion, the initially formed Me3Si+BF4ꢀ decomposed
to Me3SiF and BF3, which were inactive to ArSSAr. Another possibil-
ity to be considered is that the attack of BFꢀ4 to the silyl group led to
direct formation of Me3SiF and BF3.12
13. General procedure for the synthesis of ArS-substituted compounds: The anodic
oxidation was carried out in an H-type divided cell (4G glass filter) equipped
with a carbon felt anode (Nippon Carbon JF-20-P7, ca. 320 mg, dried at 250 °C/
1 mm Hg for 2 h before use) and a platinum plate cathode (40 mm ꢁ 20 mm).
In the anodic chamber was placed
a solution of ArSSAr (Ar = p-FC6H4)
(101.6 mg, 0.399 mmol) in 0.3 M Bu4NBF4/CH2Cl2 (8.0 mL). In the cathodic
chamber were placed 0.3 M Bu4NBF4/CH2Cl2 (8.0 mL) and trifluorometh-
anesulfonic acid (48 mg, 0.32 mmol). The constant current electrolysis
(8 mA) was carried out at ꢀ78 °C with magnetic stirring until 0.67 F/mol of
electricity was consumed. To the ArS(ArSSAr)+ thus generated in the anodic
chamber, was added 1,3,5-trimethoxybenzene (34.3 mg, 0.204 mmol) at
ꢀ78 °C and the reaction mixture was stirred for 3 min. The reaction was
quenched with Et3N (1 mL). The solvent was removed under reduced pressure
and the residue was quickly filtered through a short column (2 ꢁ 3 cm) of silica
gel to remove Bu4NBF4. The silica gel was washed with ether (150 mL), and
purified by flash chromatography to obtain the product. 2-(4-Fluorophenyl-
sulfanyl)-1,3,5-trimethoxybenzene: 1H NMR (300 MHz, CDCl3) d 3.81 (s, 6H),
3.86 (s, 3H), 6.20 (s, 2H), 6.82–6.91 (m, 2H), 6.98–7.06 (m, 2H); 13C NMR
(150 MHz, CDCl3) d 55.4, 56.2, 91.2, 99.3, 115.5 (d, J = 20.9 Hz), 127.8 (d,
J = 8.0 Hz), 133.5 (d, J = 3.2 Hz), 160.7 (d, J = 242.6 Hz), 162.3, 162.9; LRMS
(FAB) m/z 294 (M+); HRMS (FAB) calcd for C15H15FO3S (M+) 294.0726, found
294.0727. 1-(4-Fluorophenylsulfanyl)-4-methoxy-2-methylbenzene: The regio-
In conclusion, ArS(ArSSAr)+ cation pool was found to be effec-
tive reagents as ArS+ equivalent in electrophilic substitution reac-
tions of aromatic compounds, enolizable ketones, enol acetates,
ketene silyl acetals, and allylsilanes to give the corresponding aryl-
thiolated products.13 When BðC6F5Þꢀ was used as the counter an-
4
ion, the reactions of the allylsilane proceeded with a catalytic
amount of ArS(ArSSAr)+, suggesting a cation chain mechanism
involving ‘Me3Si+’.8c,e The results obtained here speak well for the
potential of an electrogenerated ArS(ArSSAr)+ cation pool as ArS+
equivalent in organic synthesis. Further investigations are in pro-
gress in our laboratory.
chemistry was determined by the coupling constant in 1H NMR and NOESY. 1
H
NMR (600 MHz, CDCl3) d 2.34 (s, 3H), 3.81 (s, 3H), 6.74 (dd, J = 8.3 Hz, 2.8 Hz,
1H), 6.84 (d, J = 2.8 Hz, 1H), 6.90–6.95 (m, 2H), 7.02–7.07 (m, 2H), 7.38 (d,
Acknowledgments
J = 8.3 Hz, 1H); 13C NMR (150 MHz, CDCl3)
d 21.0, 55.3, 112.2, 116.0 (d,
J = 21.5 Hz), 116.5, 123.4, 129.3 (d, J = 8.6 Hz), 133.1, 136.6, 143.2, 160.2, 161.2
(d, J = 242.7 Hz); LRMS (FAB) m/z 248 (M+); HRMS (FAB) calcd for C14H13FOS
(M+) 248.0671, found 248.0668. 1-Chloro-2-(4-fluorophenylsulfanyl)-3,5-
dimethoxybenzene: The regiochemistry was determined by 1H NMR. 1H NMR
(600 MHz, CDCl3) d 3.79 (s, 3H), 3.83 (s, 3H), 6.43 (d, J = 2.8 Hz, 1H), 6.70 (d,
J = 2.8 Hz, 1H), 6.87–6.94 (m, 2H), 7.06–7.11 (m, 2H); 13C NMR (150 MHz,
This work was financially supported in part by a Grant-in-Aid
for Scientific Research from the Japan Society for the Promotion
of Science. We are deeply grateful to Nippon Shokubai Co. for pro-
viding NaB(C6F5)4 as a precursor of Bu4NB(C6F5)4. We also appreci-
ate Professor Hendrik Zipse of the Ludwig-Maximilians Universität
in München for fruitful discussions. K.M. thanks the Ion Kougaku
Foundation for financial supports.
CDCl3)
d 55.7, 56.4, 98.1, 106.9, 111.7, 115.7 (d, J = 21.5 Hz), 128.9 (d,
J = 7.2 Hz), 132.3, 142.1, 161.1 (d, J = 242.7 Hz), 161.8, 162.2; LRMS (FAB) m/z
298 (M+); HRMS (FAB) calcd for C14H12ClFO2S (M+) 298.0231, found 298.0236.

K. Matsumoto et al. / Tetrahedron Letters 53 (2012) 1916–1919
1919
2-(4-Fluorophenylsulfanyl)-1-phenylethanone: 1H NMR (400 MHz, CDCl3) d 4.19
(s, 2H), 6.93–7.00 (m, 2H), 7.32–7.41 (m, 2H), 7.42–7.48 (m, 2H), 7.54–7.60 (m,
1H), 7.88–7.94 (m, 2H); 13C NMR (75 MHz, CDCl3) d 42.1, 116.2 (d, J = 21.6 Hz),
128.67, 128.70, 129.4 (d, J = 3.5 Hz), 133.5, 134.0 (d, J = 8.0 Hz), 135.3, 162.5 (d,
J = 247.1 Hz), 194.0; LRMS (CI) m/z 246 (M+), 227 (M+-F), 169 (M+-Ph), 141 (M+-
COPh), 119 (M+-SC6H4p-F); HRMS (CI) calcd for C14H11FOS (M+) 246.0515,
found 246.0516. 2-(4-Fluorophenylsulfanyl)-1-phenylpropan-1-one: 1H NMR
(600 MHz, CDCl3) d 1.49 (d, J = 6.8 Hz, 3H), 4.56 (q, J = 6.8 Hz, 1H), 6.94–7.00
(m, 2H), 7.28–7.34 (m, 2H), 7.43–7.49 (m, 2H), 7.56–7.60 (m, 1H), 7.92–7.97
(m, 2H)Hh; 13C NMR (150 MHz, CDCl3) d 16.7, 46.0, 99.9, 116.1 (d, J = 21.6 Hz),
126.2, 128.6, 133.1, 135.7, 137.6 (d, J = 8.3 Hz), 163.4 (d, J = 247.8 Hz), 195.9;
LRMS (EI) m/z 260 (M+), 155 (M+-COPh), 127 (M+-CMeCOPh); HRMS (EI) calcd
for
C
11H11FO2S (M+) 226.0464, found 226.0461. 1-(4-Fluorophenylsulfanyl)-
propan-2-one: The isolated product was identified by the comparison of its
spectral data with that of an authentic sample.14 2-(4-Fluorophenylsulfanyl)-2-
methylpropionic acid methyl ester: 1H NMR (300 MHz, CDCl3) d 1.48 (s, 6H), 3.67
(s, 3H), 6.97–7.07 (m, 2H), 7.39–7.47 (m, 2H); 13C NMR (75 MHz, CDCl3) d 25.6,
51.1, 52.2, 115.8 (d, J = 27.5 Hz), 126.7 (d, J = 3.5 Hz), 138.8 (d, J = 9.2 Hz), 163.7
(d, J = 249.4 Hz), 174.1; LRMS (CI) m/z 228(M+), 209 (M+-F);HRMS (CI) calcd for
C
11H13FO2S (M+) 228.0620, found 228.0620. 1-Fluoro-4-(cyclohex-2-enyl-
sulfanyl)benzene: 1H NMR (600 MHz, CDCl3) d 1.55–1.64 (m, 1H), 1.70–1.76
(m, 1H), 1.83–1.94 (m, 2H), 1.96–2.08 (m, 2H), 6.97–7.02 (m, 2H), 7.40–7.45
(m, 2H); 13C NMR (125 MHz, CDCl3)
d 19.4, 24.9, 28.7, 45.0, 115.9 (d,
J = 21.5 Hz), 126.9, 130.5, 130.6, 134.6 (d, J = 7.2 Hz), 162.2 (d, J = 245.6 Hz);
LRMS (CI) m/z 208 (M+), 81 (M+-SC6H4p-F); HRMS (CI) calcd for C12H13FS (M+)
208.0722, found 208.0724.
for
C
15H13FOS (M+) 260.0671, found 260.0666. 3-(4-Fluoro-phenylsulfanyl)-
pentane-2,4-dione: 1H NMR (600 MHz, CDCl3) d 2.33 (s, 6H), 6.96–7.08 (m, 4H),
17.2 (s, enol OH, 1H); 13C NMR (100 MHz, CDCl3) d 24.4, 102.1, 116.2 (d,
J = 22.2 Hz), 126.4 (d, J = 7.6 Hz), 132.6 (d, J = 3.2 Hz), 160.8 (d, J = 242.8 Hz),
197.8; LRMS (CI) m/z 226 (M+), 207 (M+-F), 183 (M+-COMe); HRMS (CI) calcd
14. Carta, A.; Loriga, M.; Paglietti, G.; Mattana, A.; Fiori, P. L.; Mollicotti, P.; Sechi, L.;
Zanetti, S. Eur. J. Med. Chem. 2004, 39, 195.