Iodine-catalyzed disulfidation of alkenes

Article abstract of DOI:10.1016/j.tet.2011.04.081

The disulfidation reactions of alkenes with disulfides were thoroughly investigated in this paper. Using H₂O or DCE as the solvent, most reactions occurred smoothly to give the corresponding disulfidated products in good to high yields at room temperature within 12 h.

Full text of DOI:10.1016/j.tet.2011.04.081

Tetrahedron 67 (2011) 4547e4551
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Iodine-catalyzed disulfidation of alkenes
*
Xiu-Ren Wang, Fan Chen
College of Chemistry and Materials Engineering, Wenzhou University, Chashan University Town, Wenzhou, Zhejiang Province 325035, People’s Republic of China
a r t i c l e i n f o
a b s t r a c t
Article history:
Received 4 March 2011
Received in revised form 16 April 2011
Accepted 22 April 2011
Available online 29 April 2011
The disulfidation reactions of alkenes with disulfides were thoroughly investigated in this paper. Using
H2O or DCE as the solvent, most reactions occurred smoothly to give the corresponding disulfidated
products in good to high yields at room temperature within 12 h.
Ó 2011 Elsevier Ltd. All rights reserved.
Keywords:
Iodine
Disulfidation
Alkene
Synthetic methods
Table 1
1. Introduction
Optimization for the I2-catalyzed disulfidation of diphenyl disulfide 1a with
styrene 2a
The disulfidation of carbonecarbon unsaturated bonds is a use-
ful method for the synthesis of organosulfur compounds, which can
be used as good intermediates in organic synthesis.1 Nowadays,
several methods have been reported in the literature. For instance,
Kitamura and Taniguchi reported the hypervalent iodine(III)
reagent induced 1,2-disulphenylation of alkenes.2 Caserio and co-
workers reported boron trifluoride catalyzed addition reaction of
disulfides to alkenes in 1985.3 In 2004, Oshima and co-workers
completed the gallium trichloride catalyzed disulfidation of
alkenes at 0 ꢀC to give the corresponding products in good to high
yields.4 In 2009, Yoshida and co-workers reported a catalytic
amount of ArSþ initiated disulfidation of dienes via intramolecular
CeC bond formation reaction.5 Though some progresses have been
made in the disulfidation of alkenes, to develop some other simple
and efficient methods for these reactions is still in demand for
chemists. Herein, we wish to report the I2-catalyzed disulfidation
reactions of alkenes under mild conditions.
PhS
Ph
I2, solvent
rt, 12 h
+
PhSSPh
1a
Ph
SPh
2a
3a
Entrya
Solvent
Yield (%)b
1
2
3
4
5
THF
DMF
H2O
CH2Cl2
DCE
Trace
d
90
94
96
a
All reactions were carried out using 1a (0.5 mmol), 2a (0.6 mmol), and I2 (10 mol%)
in the listed solvent (2.0 mL) at rt for 12 h under air.
b
Isolated yields.
(DCE) to give the corresponding disulfidation product 3a in high
yields (Table 1, entries 3e5). Almost no product was obtained when
the reaction was carried out in THF or DMF (Table 1, entries 1 and 2).
H2O matches the demand of the basic principles in Green Chemis-
try6 and it is cheap and safe enough.7 CH2Cl2 is volatile at room
temperature. So the optimal reaction solvents were H2O or DCE.
With the optimal reaction conditions in hand, we next in-
vestigate the reactions of a variety of disulfides 1 with styrene 2a.
The results are shown in Table 2. In most cases, the corresponding
disulfidation products 3 were obtained in good to high yields in
both solvents of H2O and DCE (Table 2, entries 1, 2, 4, and 5).
Substituents on substrates 1 have some effect on the reactions. For
instance, substrate 1d with 4-chlorophenyl groups only gave ac-
ceptable yield in H2O, though good yield of the corresponding
2. Results and discussion
Initial examinations were carried out using diphenyl disulfide
1a (0.5 mmol) and styrene 2a (0.6 mmol) as the substrates in the
presence of I2 (10 mol %) at room temperature for 12 h to find out
the optimal solvent. The results are summarized in Table 1. The
reaction took place very well in H2O, CH2Cl2 or 1,2-dichloroethane
* Corresponding author. Tel./fax: þ86 577 88373111; e-mail address: fanchen@
wzu.edu.cn (F. Chen).
0040-4020/$ e see front matter Ó 2011 Elsevier Ltd. All rights reserved.
doi:10.1016/j.tet.2011.04.081

4548
X.-R. Wang, F. Chen / Tetrahedron 67 (2011) 4547e4551
Table 2
Subsequently, we examined the I2-catalyzed reactions of various
disulfides 1 with alkenes 2 under the identical conditions (Table 3).
As can be seen from Table 3, good to high yields of the corre-
sponding disulfidation products 3 were achieved in H2O or DCE in
most cases with styrenes as the substrates (Table 3, entries 2e6, 9,
10, 12e15). Electron- and solvent-effect affected the reactions evi-
dently. For example, in the reactions of substrate 1d bearing
4-chlorophenyl groups with substrates 2f and 2c, very lower yields
of products 3n and 3o were obtained in H2O, while good yields
were achieved in DCE (Table 3, entries 7 and 8). For the reactions
involving substrate 2b bearing strongly electron-withdrawing
3-nitro group on the phenyl ring, only acceptable yields of prod-
ucts 3h and 3r were obtained in DCE, which are far from that
obtained in H2O (Table 3, entries 1 and 11). Cyclohexene 2i was not
a suitable substrate in this reaction and only trace of product was
formed in H2O and 25% yield was obtained in DCE, although both
reactions were carried out at 70 ꢀC (Table 3, entry 16).
I2-catalyzed reactions of a variety of disulfides 1 with styrene 2a
R1S
I2 (10 mol%)
H2O or DCE, rt, 12 h
R1SSR1
+
1
Ph
SR1
Ph
2a
3
Entrya
1 (R1)
Yields (%)b
A
B
1
2
3
4
5
6
1b (4-MeC6H4)
1c (4-MeOC6H4)
1d (4-ClC6H4)
1e (3FC6H4)
1f (4FC6H4)
1g (4NO2C6H4)
3b, 94
3c, 96
3d, 46
3e, 71
3f, 95
trace
3b, 96
3c, 93
3d, 85
3e, 74
3f, 97
trace
7
trace
trace
S
S
1h
For an initial mechanistic consideration, it seems as if a radical
route is involved in this I2-triggered disulfidation reaction of al-
kenes. The reaction of disulfide 1a with styrene 2a was tested under
the optimized conditions B in the presence of 2,6-di-tert-butyl-4-
methyl-phenol, a classical radical trap. Unexpectedly, the reaction
proceeded smoothly to give product 2a as the sole product in 99%
yield, which, to some extent, may be a proof to rule out the radical
pathway. Based on this result, a plausible mechanism for this
I2-catalyzed disulfidation reaction is shown in Scheme 1. The sul-
fonium ion 4, which is formed by oxidation of disulfide 1 with I2,
adds to alkenes 2 to form intermediate 5. Intermediate 5 reacts
S
Ph
Ph
S
8
3g, 73
3g, 56
1i
a
All reactions were carried out using 1 (0.5 mmol), 2a (0.6 mmol) and I2 (10 mol%)
in H2O (2.0 mL, A) or DCE (2.0 mL, B) at rt for 12 h under air.
b
Isolated yields.
product 3d was obtained in DCE (Table 2, entry 3). For substrate 1e
with 3-fluorophenyl groups, lower yields of product 3e were
obtained in H2O or DCE (Table 2, entry 4). With di-(4-nitrophenyl)
disulfide 1g having strongly electron-withdrawing groups on the
phenyl rings and dicyclohexyl disulfide 1h as the substrates, re-
spectively, almost no reactions occurred in H2O or DCE (Table 2,
entries 6 and 7). Dibenzyl disulfide 1i also gave moderate yields in
H2O or DCE, respectively (Table 2, entry 8).
with another disulfide molecule to afford product
3 with
regeneration of the sulfonium ion 4 to furnish the catalytic cycle.
R1SSR1
1
SR1
I2
R1S+
4
R1S
R2
3
R2
R1
S
2
Table 3
+
I2-catalyzed reactions of disulfides 1 with alkenes 2
R1SSR1
1
R1S
R2
5
I2 (10 mol%)
H2O or DCE, 12 h
1SSR1
1
+
R
SR1
3
R2
R2
Scheme 1. Proposed mechanism.
2
Entrya
1 (R1)
2 (R2)
Yields (%)b
A
3. Conclusion
B
1
2
3
4
5
6
7
8
1b (4-MeC6H4)
1b
1b
1b
2b (3NO2C6H4)
2c (4FC6H4)
2d (4-ClC6H4)
2e (2-ClC6H4)
2f (3-MeC6H4)
2f
2f
2c
2g (4-MeC6H4)
2f
2b
2c
2d
2e
3h, 98
3i, 92
3j, 99
3k, 98
3l, 92
3m, 99
3n, 19
3o, 49
3p, 72
3q, 88
3r, 98
3s, 89
3t, 95
3u, 99
3v, 95
3h, 58
3i, 91
3j, 98
3k, 90
3l, 93
3m, 97
3n, 84
3o, 79
3p, 80
3q, 91
3r, 42
3s, 86
3t, 86
3u, 81
3v, 82
In summary, I2 was found to be an efficient catalyst in the
disulfidation reactions of aromatic alkenes in H2O and DCE, re-
spectively. This strategy will be useful synthetic methods for the
disulfidation of aromatic alkenes, complementary to the reported
Lewis acid catalyzed addition reactions of disulfides to alkenes.
1b
1c (4-MeOC6H4)
1d (4-ClC6H4)
1d
1a (Ph)
1a
1a
1a
1a
1a
9
4. Experimental section
4.1. General methods
10
11
12
13
14
15
1H and 13C NMR spectra were recorded on a Bruker Avance-300
or 500 MHz spectrometer for solution in CDCl3 with tetrame-
thylsilane (TMS) as an internal standard; J-values are in hertz. THF
was distilled from sodium (Na) under nitrogen (N2) atmosphere.
DMF, CH2Cl2, and 1,2-dichloroethane (DCE) were distilled from
CaH2 under nitrogen (N2) atmosphere. Commercially obtained re-
agents were used without further purification. Flash column
chromatography was carried out using Huanghai 300e400 mesh
silica gel at increased pressure.
1a
2h (2-BrC6H4)
16c
1a
Trace
3w, 25
2i
a
Otherwizespecified, all reactions werecarried outusing1(0.5mmol), 2 (0.6mmol)
and I2 (10 mol%) in H2O (2.0 mL, A) or DCE (2.0 mL, B) at rt for 12 h under air.
b
Isolated yields.
The reaction was carried out at 70 ꢀC.
c

X.-R. Wang, F. Chen / Tetrahedron 67 (2011) 4547e4551
4549
4.2. Experimental procedures
JCeF¼3.3 Hz), 128.5, 128.0, 127.8, 116.02 (d, JCeF¼21.8 Hz), 115.95 (d,
JCeF¼21.6 Hz), 53.4, 40.7. IR (CH2Cl2)
n 3052, 2917, 2847, 1588, 1488,
General Procedure for the I2-catalyzed disulfidation of alkenes: into
a reaction tube were added disulfide 1 (0.5 mmol), I2 (10 mol %), H2O
or DCE (2.0 mL), and alkenes 2 (0.6 mmol) successively. The mixture
was stirred at room temperature for 12 h. Then the reaction was
quenched with saturated aqueous Na2SO3. The mixture was
extracted with EtOAc, dried over anhydrous Na2SO4, filtered, and
purified by flash column chromatography to give the pure products.
1265, 1224, 1155, 1013, 828, 739, 698 cmꢁ1. MS (%) m/z 358 (Mþ, 1),
153 (100), 231 (87), 153 (100), 127 (66). HRMS (EI) calcd for
C20H16F2S2: 358.0662, found: 358.0646.
4.2.7. Compound 3g. A colorless liquid. 1H NMR (300 MHz, CDCl3,
TMS)
(m, 4H), 2.89e2.76 (m, 2H). 13C NMR (125 MHz, CDCl3, TMS)
138.01, 137.95, 128.92, 128.87, 128.5, 128.43, 128.41, 128.2, 127.6,
d
7.35e7.13 (m,15H, Ar), 3.72 (dd, J¼8.7, 6.6 Hz,1H), 3.56e3.39
d
140.9,
4.2.1. Compound 3a8. A colorless liquid. 1H NMR (300 MHz, CDCl3,
127.0, 49.1, 37.3, 36.7, 35.8. IR (CH2Cl2) n 3051,1583,1532,1490,1477,
TMS)
d
7.29e7.16 (m, 15H, Ar), 4.25 (dd, J¼9.9, 5.1 Hz, 1H), 3.49 (dd,
1439, 1353, 1265, 1225, 1157, 816, 741, 698 cmꢁ1. MS (%) m/z 350
(Mþ, 1), 91 (100). HRMS (EI) calcd for C22H22S2: 350.1163, found:
350.1171.
J¼13.5, 5.1 Hz, 1H), 3.35 (dd, J¼13.5, 9.9 Hz, 1H). 13C NMR (125 MHz,
CDCl3, TMS)
d 139.6, 135.5, 134.1, 132.8, 129.9, 128.89, 128.87, 128.5,
128.0, 127.7, 127.6, 126.4, 52.4, 39.7.
4.2.8. Compound 3h. A white solid, Mp: 79e80 ꢀC. 1H NMR
4.2.2. Compound 3b9. A white solid, Mp: 67e68 ꢀC. 1H NMR
(500 MHz, CDCl3, TMS)
d
8.06 (d, J¼8.0 Hz, 1H, Ar), 7.96 (s, 1H, Ar),
(500 MHz, CDCl3, TMS)
d
7.29e7.21 (m, 5H, Ar), 7.16 (d, J¼8.0 Hz,
7.49 (d, J¼7.5 Hz, 1H, Ar), 7.40 (t, J¼7.5 Hz, 1H, Ar), 7.14 (d, J¼7.0 Hz,
2H, Ar), 7.07e7.01 (m, 6H, Ar), 4.23 (dd, J¼10.5, 4.0 Hz,1H), 3.50 (dd,
J¼13.5, 4.0 Hz, 1H), 3.28 (dd, J¼13.5, 10.5 Hz, 1H), 2.31 (s, 3H, Me)
2H, Ar), 7.06 (d, J¼8.0 Hz, 2H, Ar), 7.02 (d, J¼7.0 Hz, 2H, Ar), 7.01 (d,
J¼7.0 Hz, 2H, Ar), 4.17 (dd, J¼10.0, 5.0 Hz, 1H), 3.44 (dd, J¼13.5,
5.0 Hz,1H), 3.29 (dd, J¼13.5,10.0 Hz,1H), 2.30 (s, 6H, 2Me). 13C NMR
2.30 (s, 3H, Me). 13C NMR (125 MHz, CDCl3, TMS)
d 148.0, 142.1,
(125 MHz, CDCl3, TMS)
d
139.8, 137.8, 136.4, 133.4, 131.7, 130.5,
138.6, 137.0, 134.4, 133.9, 131.0, 130.8, 129.81, 129.77, 129.1, 128.9,
123.1, 122.4, 52.3, 39.6, 21.1, 20.9. IR (CH2Cl2) 3050, 2919, 2851,
130.4, 129.63, 129.60, 128.4, 128.1, 127.6, 52.6, 40.0, 21.1, 21.0.
n
1528, 1477, 1439, 1349, 1265, 1210, 1158, 1096, 1014, 808, 739,
704 cmꢁ1. MS (%) m/z 395 (Mþ, 3), 272 (76), 149 (47), 139 (44), 123
(100). HRMS (EI) calcd for C22H21NO2S2: 395.1014, found: 395.1014.
4.2.3. Compound 3c. A white solid, Mp: 56e57 ꢀC. 1H NMR
(500 MHz, CDCl3, TMS)
d 7.26e7.18 (m, 3H, Ar), 7.17e7.14 (m, 6H,
Ar), 6.77e6.72 (m, 4H, Ar), 4.05 (dd, J¼10.0, 5.0 Hz, 1H), 3.77 (s, 3H,
OMe), 3.76 (s, 3H, OMe), 3.36 (dd, J¼13.5, 5.0 Hz, 1H), 3.25 (dd,
4.2.9. Compound 3i. A white solid, Mp: 79e80 ꢀC. 1H NMR
(500 MHz, CDCl3, TMS) d 7.17e7.14 (m, 4H, Ar), 7.07e7.02 (m, 6H,
J¼13.5, 10.0 Hz, 1H). 13C NMR (125 MHz, CDCl3, TMS)
d
159.7, 159.0,
139.9, 135.9, 133.5, 128.3, 128.1, 127.5, 125.6, 124.1, 114.5, 114.3, 55.3,
Ar), 6.95 (t, J¼8.5 Hz, 2H, Ar), 4.15 (dd, J¼10.5, 4.5 Hz, 1H), 3.43 (dd,
55.2, 53.3, 41.0. IR (CH2Cl2)
n 3049, 2953, 2914, 2834, 1589, 1491,
J¼13.5, 4.5 Hz, 1H), 3.23 (dd, J¼13.5, 10.5 Hz, 1H), 2.32 (s, 3H, Me),
1284, 1265, 1241, 1171, 1027, 906, 825, 738, 698 cmꢁ1. MS (%) m/z
382 (Mþ, 1), 139 (100). HRMS (EI) calcd for C22H22O2S2: 382.1061,
found: 382.1058.
2.31 (s, 3H, Me). 13C NMR (125 MHz, CDCl3, TMS)
d 162.1 (d,
JCeF¼244.8 Hz), 138.0, 136.6, 135.6 (d, JCeF¼3.1 Hz), 133.5, 131.5,
130.6, 130.0, 129.674, 129.667 (d, JCeF¼8.0 Hz), 115.3 (d,
JCeF¼21.4 Hz), 51.9, 40.1, 21.1, 21.0. IR (CH2Cl2)
n 3021, 2954, 2919,
4.2.4. Compound 3d. A white solid, Mp: 61e62 ꢀC. 1H NMR
2849, 1604, 1508, 1491, 1477, 1439, 1264, 1227, 1158, 1095, 1068,
1015, 909, 839, 808, 739, 693 cmꢁ1. MS (%) m/z 368 (Mþ, 1), 245
(52), 149 (100), 123 (97). HRMS (EI) calcd for C22H21FS2: 368.1069,
found: 368.1068.
(500 MHz, CDCl3, TMS)
d 7.29e7.23 (m, 3H, Ar), 7.20e7.17 (m, 8H,
Ar), 7.15e7.09 (m, 2H, Ar), 4.17 (dd, J¼9.5, 5.5 Hz, 1H), 3.40 (dd,
J¼13.5, 5.5 Hz, 1H), 3.32 (dd, J¼13.5, 9.5 Hz, 1H). 13C NMR (125 MHz,
CDCl3, TMS)
d 139.1, 134.3, 134.0, 133.8, 132.6, 132.3, 131.5, 129.05,
129.04, 128.6,128.0,127.9, 52.8, 40.0. IR (CH2Cl2)
n
3049, 2360,1509,
4.2.10. Compound 3j. A white solid, Mp: 76e77 ꢀC. 1H NMR
1475, 1388, 1265, 1226, 1159, 1094, 1013, 816, 742, 697 cmꢁ1. MS (%)
m/z 247 [(MꢁC6H4ClS)þ, 53], 169 (100), 143 (72), 108 (64), 104 (54).
HRMS (EI) calcd for C20H16Cl2S2: 390.0070, found: 390.0068.
(500 MHz, CDCl3, TMS)
d
7.24e7.21 (m, 2H, Ar), 7.14 (d, J¼8.0 Hz, 2H,
Ar), 7.11 (d, J¼8.5 Hz, 2H, Ar), 7.07e7.01 (m, 6H, Ar), 4.13 (dd, J¼10.5,
5.0 Hz, 1H), 3.43 (dd, J¼13.5, 5.0 Hz, 1H), 3.22 (dd, J¼13.5, 10.5 Hz,
1H), 2.31 (s, 6H, 2Me). 13C NMR (125 MHz, CDCl3, TMS)
d 138.4,
4.2.5. Compound 3e. A pale yellow liquid. 1H NMR (500 MHz,
138.0, 136.6, 133.5, 133.2, 131.4, 130.7, 129.8, 129.7, 129.4, 128.5, 52.0,
CDCl3, TMS)
d
7.30e7.26 (m, 5H, Ar), 7.21e7.15 (m, 2H, Ar), 7.05 (d,
39.9, 21.1, 21.0. IR (CH2Cl2) n 3022, 2917, 2849, 1583, 1514, 1490,
J¼7.5 Hz, 1H, Ar), 6.99e6.90 (m, 3H, Ar), 6.87e6.86 (m, 2H, Ar), 4.29
1439, 1407, 1265, 1090, 1014, 909, 806, 739, 693 cmꢁ1. MS (%) m/z
384 (Mþ, 1), 261 (33), 149 (100), 123 (97). HRMS (EI) calcd for
C22H21ClS2: 384.0773, found: 384.0772.
(dd, J¼9.0, 4.5 Hz,1H), 3.46 (dd, J¼13.5, 4.5 Hz,1H), 3.36 (dd, J¼13.5,
9.0 Hz, 1H). 13C NMR (125 MHz, CDCl3, TMS)
d 162.7 (d,
JCeF¼247.1 Hz), 162.5 (d, JCeF¼247.8 Hz), 139.0, 137.7 (d,
JCeF¼7.6 Hz), 136.3 (d, JCeF¼7.6 Hz), 130.2 (d, JCeF¼2.0 Hz), 130.1 (d,
JCeF¼1.9 Hz), 128.6, 128.0, 127.9, 127.8 (d, JCeF¼3.0 Hz), 125.1 (d,
JCeF¼2.9 Hz), 119.0 (d, JCeF¼22.0 Hz), 116.3 (d, JCeF¼22.6 Hz), 114.6
4.2.11. Compound 3k. A colorless liquid. 1H NMR (500 MHz, CDCl3,
TMS)
d
7.33 (dd, J¼7.0, 1.5 Hz, 1H, Ar), 7.27e7.25 (m, 1H, Ar),
7.18e7.11 (m, 6H, Ar), 7.09e6.99 (m, 4H, Ar), 4.79 (dd, J¼10.0, 5.5 Hz,
1H), 3.42 (dd, J¼13.5, 5.5 Hz, 1H), 3.36 (dd, J¼13.5, 10.5 Hz, 1H), 2.30
(d, JCeF¼21.0 Hz), 113.4 (d, JCeF¼21.0 Hz), 52.3, 39.5. IR (CH2Cl2)
n
3061, 2953, 1598, 1577, 1490, 1474, 1453, 1426, 1264, 1217, 1157,
1066, 878, 816, 775, 741, 698 cmꢁ1. MS (%) m/z 358 (Mþ, 4), 231 (96),
217 (50), 153 (100). HRMS (EI) calcd for C20H16F2S2: 358.0662,
found: 358.0666.
(s, 3H, Me), 2.29 (s, 3H, Me). 13C NMR (125 MHz, CDCl3, TMS)
d 137.9,
137.2, 136.6, 134.3, 133.4, 131.4, 131.0, 129.8, 129.7, 129.59, 129.57,
128.6, 128.5, 126.8, 48.2, 39.6, 21.1, 21.0. IR (CH2Cl2) 3022, 2953,
n
2918, 1509, 1490, 1476, 1439, 1265, 1158, 1121, 1016, 909, 809, 740,
704, 679 cmꢁ1. MS (%) m/z 384 (Mþ, 9), 263 (41), 261 (100),149 (99),
123 (53). HRMS (EI) calcd for C22H21ClS2: 384.0773, found:
384.0770.
4.2.6. Compound 3f. A white solid, Mp: 65e66 ꢀC. 1H NMR
(500 MHz, CDCl3, TMS)
d 7.28e7.15 (m, 9H, Ar), 6.94e6.89 (m, 4H,
Ar), 4.10 (dd, J¼10.0, 5.0 Hz, 1H), 3.38 (dd, J¼13.5, 5.0 Hz, 1H), 3.31
(dd, J¼13.5, 10.0 Hz, 1H). 13C NMR (125 MHz, CDCl3, TMS)
d
162.7 (d,
4.2.12. Compound 3l. A pale yellow solid, Mp: 49e50 ꢀC. 1H NMR
JCeF¼247.1 Hz), 162.0 (d, JCeF¼245.8 Hz), 139.4, 135.9 (d,
JCeF¼8.3 Hz), 133.1 (d, JCeF¼8.0 Hz), 130.2 (d, JCeF¼3.3 Hz), 128.8 (d,
(500 MHz, CDCl3, TMS)
d 7.18e7.15 (m, 3H, Ar), 7.06e7.00 (m, 9H,
Ar), 4.15 (dd, J¼10.0, 5.0 Hz, 1H), 3.42 (dd, J¼13.5, 5.0 Hz, 1H), 3.30

4550
X.-R. Wang, F. Chen / Tetrahedron 67 (2011) 4547e4551
(dd, J¼13.5, 10.5 Hz,1H), 2.31 (s, 3H, Me), 2.30 (s, 6H, 2Me). 13C NMR
(dd, J¼10.5, 4.5 Hz, 1H), 3.55 (dd, J¼14.0, 4.5 Hz, 1H), 3.33 (dd,
(125 MHz, CDCl3, TMS)
d
139.5, 138.0, 137.7, 136.3, 133.3, 131.8,
J¼14.0, 10.5 Hz, 1H). 13C NMR (125 MHz, CDCl3, TMS)
d 148.1, 141.9,
130.53, 130.46, 129.6, 128.7, 128.4, 128.3, 125.1, 52.5, 40.0, 21.4, 21.1,
134.5, 134.3, 133.4, 132.7, 130.4, 129.3, 129.13, 129.07, 128.3, 126.9,
21.0. IR (CH2Cl2)
n
3051, 2953, 2917, 1532, 1490, 1438, 1353, 1265,
123.2, 122.6, 52.1, 39.3. IR (CH2Cl2) n 3049, 1581, 1527, 1479, 1438,
1226, 1159, 1016, 800, 738, 703 cmꢁ1. MS (%) m/z 364 (Mþ, 1), 241
(22), 149 (100), 123 (39). HRMS (EI) calcd for C23H24S2: 364.1319,
found: 364.1315.
1350, 1265, 1227, 1156, 1024, 890, 736, 690 cmꢁ1. MS (%) m/z 367
(Mþ, 1), 258 (41), 135 (54), 109 (100). HRMS (EI) calcd for
C20H17NO2S2: 367.0701, found: 367.0704.
4.2.13. Compound 3m. A colorless liquid. 1H NMR (500 MHz, CDCl3,
4.2.19. Compound 3s. A white solid, Mp: 52e53 ꢀC. 1H NMR
TMS)
d
7.21e7.12 (m, 5H, Ar), 7.04 (d, J¼8.0 Hz, 1H, Ar), 6.96 (d,
(500 MHz, CDCl3, TMS) d 7.28e7.14 (m, 12H, Ar), 6.98e6.95 (m, 2H,
J¼6.0 Hz, 2H, Ar), 6.77e6.73 (m, 4H, Ar), 4.02 (dd, J¼10.0, 5.0 Hz,
1H), 3.77 (s, 6H, 2OMe), 3.34 (dd, J¼13.5, 5.0 Hz, 1H), 3.25 (dd,
J¼13.5, 10.5 Hz, 1H), 2.29 (s, 3H, Me). 13C NMR (125 MHz, CDCl3,
Ar), 4.23 (dd, J¼10.5, 4.5 Hz, 1H), 3.49 (dd, J¼13.5, 4.5 Hz, 1H), 3.29
(dd, J¼13.5, 10.5 Hz, 1H). 13C NMR (125 MHz, CDCl3, TMS)
d 162.1 (d,
JCeF¼245.0 Hz), 135.3 (d, JCeF¼3.1 Hz), 135.2, 133.7, 133.0, 130.0,
129.7 (d, JCeF¼8.1 Hz), 128.9, 127.8, 126.5, 115.3 (d, JCeF¼21.5 Hz),
TMS)
d 159.7, 158.9, 139.6, 137.9, 135.9, 133.4, 128.7, 128.3, 128.2,
125.7, 125.2, 124.3, 114.4, 114.3, 55.2, 53.3, 40.9, 21.4. IR (CH2Cl2)
n
51.7, 39.7. IR (CH2Cl2) n 3049, 1603, 1582, 1508, 1479, 1438, 1265,
3051, 2954, 1590, 1532, 1492, 1439, 1353, 1265, 1243, 1172, 1070,
1026, 825, 738, 704 cmꢁ1. MS (%) m/z 257 [(MꢁC7H7OS)þ, 15], 165
(22), 139 (100). HRMS (EI) calcd for C23H24O2S2: 396.1218, found:
396.22.12.
1223, 1158, 1024, 1012, 906, 838, 738, 689 cmꢁ1. MS (%) m/z 340
(Mþ, 1), 231 (84), 217 (31), 135 (100), 109 (76). HRMS (EI) calcd for
C20H17FS2: 340.0756, found: 340.0750.
4.2.20. Compound 3t. A white solid, Mp: 61e62 ꢀC. 1H NMR
4.2.14. Compound 3n. A colorless liquid. 1H NMR (500 MHz, CDCl3,
TMS)
(300 MHz, CDCl3, TMS)
4.8 Hz, 1H), 3.49 (dd, J¼13.5, 4.8 Hz, 1H), 3.28 (dd, J¼13.5, 10.5 Hz,
1H). 13C NMR (125 MHz, CDCl3, TMS)
138.2, 135.1, 133.6, 133.4,
133.1, 130.1, 129.4, 128.995, 128.982, 128.6, 127.9, 126.6, 51.8, 39.6. IR
d
7.25e7.13 (m, 14H, Ar), 4.21 (dd, J¼10.5,
d 7.20e7.16 (m, 7H, Ar), 7.10e7.06 (m, 3H, Ar), 7.00 (d,
J¼5.5 Hz, 2H, Ar), 4.14 (dd, J¼9.5, 5.5 Hz, 1H), 3.38 (dd, J¼13.5,
d
5.5 Hz, 1H), 3.33 (dd, J¼13.5, 9.5 Hz, 1H), 2.30 (s, 3H, Me). 13C NMR
(125 MHz, CDCl3, TMS)
d
138.9, 138.2, 134.1, 133.8, 132.5, 131.4,
(CH2Cl2) n 3057, 1582, 1532, 1490, 1479, 1438, 1353,1265, 1224,1156,
129.0, 128.9, 128.7, 128.5, 128.4, 125.0, 52.8, 39.9, 21.3. IR (CH2Cl2)
n
1090, 1024, 1013, 906, 837, 740, 690 cmꢁ1. MS (%) m/z 356 (Mþ, 1),
247 (44), 135 (100), 109 (69). HRMS (EI) calcd for C20H17ClS2:
356.0460, found: 356.0461.
3004, 2952, 1606, 1573, 1514, 1475, 1439, 1388, 1265, 1093, 1012,
818, 739, 702 cmꢁ1. MS (%) m/z 261 [(MꢁC6H4ClS)þ, 29], 171 (37),
169 (100), 143 (38), 118 (36), 108 (34). HRMS (EI) calcd for
C21H18Cl2S2: 404.0227, found: 404.0226.
4.2.21. Compound 3u. A pale yellow liquid. 1H NMR (300 MHz,
CDCl3, TMS)
(dd, J¼9.3, 6.0 Hz,1H), 3.48 (dd, J¼13.8, 6.0 Hz,1H), 3.41 (dd, J¼13.8,
9.3 Hz, 1H). 13C NMR (125 MHz, CDCl3, TMS)
137.1, 135.1, 134.3,
133.7, 132.8, 130.4, 129.7, 128.90, 128.86, 128.7, 128.6, 127.7, 127.0,
d 7.35e7.28 (m, 4H, Ar), 7.23e7.15 (m, 10H, Ar), 4.88
4.2.15. Compound 3o. A white solid, Mp: 55e56 ꢀC. 1H NMR
(500 MHz, CDCl3, TMS)
d
7.19e7.13 (m, 8H, Ar), 7.09 (d, J¼8.5 Hz, 2H,
d
Ar), 6.95 (t, J¼8.5 Hz, 2H, Ar), 4.15 (dd, J¼10.0, 5.0 Hz, 1H), 3.39 (dd,
J¼13.5, 5.0 Hz, 1H), 3.26 (dd, J¼13.5, 10.0 Hz, 1H). 13C NMR
126.6, 48.1, 39.2. IR (CH2Cl2)
n 3052, 1582, 1472, 1438, 1265, 1157,
(125 MHz, CDCl3, TMS)
d
162.1 (d, JCeF¼245.6 Hz), 134.9 (d,
1123, 1068, 1024, 908, 815, 739, 690 cmꢁ1. MS (%) m/z 356 (Mþ, 4),
249 (32), 247 (83), 135 (100), 109 (46). HRMS (EI) calcd for
C20H17ClS2: 356.0460, found: 356.0453.
JCeF¼3.3 Hz), 134.4, 134.2, 133.6, 132.7, 131.9, 131.5, 129.6 (d,
JCeF¼8.1 Hz), 129.08, 129.06, 115.4 (d, JCeF¼21.4 Hz), 52.0, 40.0. IR
(CH2Cl2)
n 3023, 2952, 1604, 1574, 1508, 1476, 1438, 1389, 1265,
1228, 1159, 1095, 1013, 910, 820, 741, 692 cmꢁ1. MS (%) m/z 265
[(MꢁC6H4ClS)þ, 57], 169 (93), 143 (100), 122 (61), 108 (80). HRMS
(EI) calcd for C20H15Cl2FS2: 407.9976, found: 407.9971.
4.2.22. Compound 3v. A colorless liquid. 1H NMR (500 MHz, CDCl3,
TMS)
(m, 9H, Ar), 7.08 (t, J¼7.5 Hz, 1H, Ar), 4.87 (dd, J¼8.0, 6.5 Hz, 1H),
3.39e3.47 (m, 2H). 13C NMR (125 MHz, CDCl3, TMS)
138.6, 135.1,
133.7, 133.0, 132.9, 130.5, 129.0, 128.92, 128.87, 128.7, 127.7, 127.6,
d
7.52 (d, J¼8.0 Hz, 1H, Ar), 7.34e7.30 (m, 3H, Ar), 7.23e7.16
d
4.2.16. Compound 3p. A pale yellow liquid. 1H NMR (500 MHz,
CDCl3, TMS)
3.47 (dd, J¼13.5, 5.0 Hz, 1H), 3.32 (dd, J¼13.5, 10.0 Hz, 1H), 2.30 (s,
3H, Me). 13C NMR (125 MHz, CDCl3, TMS)
137.4, 136.4, 135.5, 134.3,
132.6, 129.8, 129.2, 128.8, 127.9, 127.4, 126.3, 51.9, 39.6, 21.1. IR
d
7.29e7.08 (m, 14H, Ar), 4.24 (dd, J¼10.0, 5.0 Hz, 1H),
126.6, 125.2, 50.7, 39.3. IR (CH2Cl2) n 3049, 1583, 1508, 1478, 1438,
1265, 1226, 1157, 1023, 816, 741, 691 cmꢁ1. MS (%) m/z 400 (Mþ, 1),
293 (19), 291 (20), 135 (100), 109 (84). HRMS (EI) calcd for
C20H17BrS2: 399.9955, found: 399.9948.
d
(CH2Cl2)
n 3050, 2920, 2846, 1582, 1513, 1480, 1438, 1265, 1086,
1068, 1024, 908, 818, 736, 690 cmꢁ1. MS (%) m/z 336 (Mþ, 2), 227
(63), 135 (100), 117 (64), 109 (46). HRMS (EI) calcd for C21H20S2:
336.1006, found: 336.1008.
4.2.23. Compound 3w10. A pale yellow liquid. 1H NMR (500 MHz,
CDCl3, TMS)
d7.32e7.30(m,4H, Ar),7.26e7.23(m,6H, Ar), 3.28(s, 2H),
2.28e2.24 (m, 2H), 1.67e1.62 (m, 4H), 1.43e1.42 (m, 2H). 13C NMR
(125 MHz, CDCl3, TMS) d 134.7, 132.3, 128.9, 127.0, 49.6, 29.7, 23.4.
4.2.17. Compound 3q. A pale yellow liquid. 1H NMR (500 MHz,
CDCl3, TMS)
d 7.30e7.28 (m, 2H, Ar), 7.23e7.14 (m, 9H, Ar), 7.05
Acknowledgements
(s, 3H, Ar), 4.22 (dd, J¼10.0, 4.5 Hz,1H), 3.47 (dd, J¼13.5, 4.5 Hz,1H),
3.35 (dd, J¼13.5, 10.0 Hz, 1H), 2.30 (s, 3H, Me). 13C NMR (125 MHz,
Financial support from the Science and Technology Department
of Zhejiang Province is greatly acknowledged.
CDCl3, TMS)
d 139.3, 138.1, 135.5, 134.3, 132.7, 129.9, 128.9, 128.8,
128.7, 128.6, 128.3, 127.5, 126.3, 125.1, 52.3, 39.5, 21.4. IR (CH2Cl2)
n
3017, 2952, 2920,1606,1583,1512,1478,1264,1158,1096,1067,1014,
854, 823, 737, 690 cmꢁ1. MS (%) m/z 336 (Mþ, 3), 227 (76), 213 (30),
135 (100). HRMS (EI) calcd for C21H20S2: 336.1006, found: 336.1001.
Supplementary data
Supplementary data associated with this article can be found in
the online version, at doi:10.1016/j.tet.2011.04.081. These data in-
clude MOL files and InChiKeys of the most important compounds
described in this article.
4.2.18. Compound 3r. A white solid, Mp: 67e68 ꢀC. 1H NMR
(500 MHz, CDCl3, TMS)
d
8.08e8.02 (m, 2H, Ar), 7.52 (d, J¼7.5 Hz,
1H, Ar), 7.41 (t, J¼8.0 Hz, 1H, Ar), 7.27e7.15 (m, 10H, Ar), 4.31

X.-R. Wang, F. Chen / Tetrahedron 67 (2011) 4547e4551
4551
7. (a) Organic Synthesis in Water; Grieco, P. A., Ed.; Blackie: London, 1998; (b) Li, C.-
J.; Chan, T. H. Organic Reactions in Aqueous Media; Wiley: New York, NY, 1997;
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