Synthesis of Trisubstituted Vinyl Sulfides via Oxidative Thiolation Initiated Cascade Reaction of Alkynoates with Thiols

Article abstract of DOI:10.1021/acs.joc.6b01770

A thiolation initiated cascade reaction of aryl alkynoates has been developed with thiol as a coupling partner. This radical process has been demonstrated to proceed through S-H bond cleavage, thiolation of alkynoate, aryl migration, and decarboxylation. This reaction tolerates a wide scope of substrates resulting in good chemical yields, which provides an easy and practical strategy for preparation of trisubstituted vinyl sulfides.

Full text of DOI:10.1021/acs.joc.6b01770

Note
pubs.acs.org/joc
Synthesis of Trisubstituted Vinyl Sulfides via Oxidative Thiolation
Initiated Cascade Reaction of Alkynoates with Thiols
Shengyang Ni,† Lijun Zhang,† Wenzhong Zhang,† Haibo Mei,† Jianlin Han,*,†,‡ and Yi Pan†,‡
†School of Chemistry and Chemical Engineering, State Key laboratory of Coordination Chemistry, Nanjing University, Nanjing
210093, China
‡MaAnShan High-Tech Research Institute of Nanjing University, MaAnShan 238200, China
S
* Supporting Information
ABSTRACT: A thiolation initiated cascade reaction of aryl
alkynoates has been developed with thiol as a coupling partner.
This radical process has been demonstrated to proceed
through S−H bond cleavage, thiolation of alkynoate, aryl
migration, and decarboxylation. This reaction tolerates a wide
scope of substrates resulting in good chemical yields, which
provides an easy and practical strategy for preparation of
trisubstituted vinyl sulfides.
Scheme 1. Synthesis of Vinyl Sulfides
hemistry of sulfur has a profound effect on our daily lives,
Cand the areas include energy, industry, food, healthcare,
and so on.1 Among the organosulfur compounds, vinyl sulfide
takes up an important part, which widely exists in many natural
products and biologically active molecules.2 Vinyl sulfides are
also versatile building blocks in organic synthesis and total
synthesis of natural products.3 For example, they can be used
for Michael addition acceptors for preparation of benzylth-
iocrellidone4 and Diels−Alder cycloaddition substrates for the
total synthesis of (−)-β-selinene.5 In the past decade, varieties
of approaches have been developed as the preparation of
substituted vinyl sulfides.6,7 The mostly reported synthetic
methods focused on metal-catalyzed cross-coupling reaction of
vinyl halides with thiols,8 and addition of thiols to the triple
bond of alkynes.9 In 2015, Kurahashi and Matsubara group
described a nickel-catalyzed synthetic method for tetrasub-
stituted vinyl sulfides by reaction of internal alkynes with
thiocarbamates as sulfur precursors.10 Recently, Zhang group
developed a copper and iodine-mediated C−H oxidative
sulfonylation of olefins with diaryl disulfides for the synthesis
of vinyl thioether (Scheme 1b).11 These approaches usually
need transition-metal catalysts or stoichiometric additives for
the transformations. So, the development of new, conceptually
different methods for more practical preparation of vinyl
sulfides remains a significant challenge.
affords alkyl, ether, benzyl and iodo substituted alkenes as
products.15
Since the substituted alkenes could be easily prepared from
the cascade reaction of aryl alkynoates, we envision that the
vinyl sulfides could be obtained from the reaction of alkynoates
with suitable sulfur precursor. Herein, we would like to report
an easy and efficient method for the preparation of vinyl
sulfides by the reaction of alkynoate with thiol16 as sulfur
precursor under metal-free condition (Scheme 1c). To the best
of our knowledge, oxidative thiolation initiating aryl migration
and decarboxylation of aryl alkynoates, has never been
reported. Furthermore, this method provides a new strategy
for the preparation of vinyl sulfides with readily available aryl
alkynoates as starting materials without use of any metal-
catalyst.
Aryl alkynoate representing an attractive intermediate, which
could construct substituted coumarin derivatives by intra-
molecular cyclization reaction.12 Also, alkynoates could under-
go transition-metal catalyzed oxidative ipso-cyclization reaction
to afford azaspiro[4.5]trienones derivatives.13 Alkynoates have
also been developed to react with ketene silyl acetals via [2+2]-
cycloaddition affording functionalized cyclobutenediones.14
Very recently, cascade migration and decarboxylation reaction
of alkynoate represents a new trend for this intermediate, which
Received: July 24, 2016
© XXXX American Chemical Society
A
DOI: 10.1021/acs.joc.6b01770
J. Org. Chem. XXXX, XXX, XXX−XXX

The Journal of Organic Chemistry
Note
Based on the previous reports and our experience on the
reactions of alkynoates,15 phenyl alkynoate 1a and 4-
methylbenzenethiol 2a were chosen as the model substrates
for this thiolation initiated reaction. The reaction was carried
out in acetonitrile at 120 °C with the use of additive. In the
presence of TBAI, the reaction could happen, and afforded the
corresponding vinyl sulfides in only 10% chemical yield (entry
1, Table 1). To our delight, application of molecular iodine as
alkynoates 1a with varieties of thiols (Scheme 2). As shown in
Scheme 2, the reaction proceeded smoothly for a wide range of
a,b
Scheme 2. Substrate Scope of Thiols
a
Table 1. Optimization of the Reaction Conditions
oxidant
(equiv)
2a
(equiv)
temp
(°C)
yield
b
entry
additive
(%)
c
1
TBAI
2
120
120
120
120
120
120
120
120
120
120
120
120
120
120
120
120
100
120
120
10
40
48
23
57
14
17
44
68
79
75
58
67
60
62
c
2
I2
2
d
e
3
DTBP (3.0)
2
a
Reaction conditions: 1a (0.2 mmol), DCP (0.2 mmol), 2 (0.4
mmol), with acetonitrile (2.0 mL) as solvent at 120 °C for 24 h.
4
TBHP (3.0)
2
f
5
DCP (3.0)
2
b
g
Isolated yield.
6
BPO (3.0)
2
h
7
TBPB (3.0)
DCP (0.2)
DCP (0.5)
DCP (1.0)
DCP (1.5)
DCP (2.0)
DCP (1.0)
DCP (1.0)
DCP (1.0)
DCP (1.0)
DCP (1.0)
2
thiols to give the corresponding vinyl sulfides with 52−76%
chemical yields. The substituents on the aromatic ring of thiols,
including methyl, chloro, bormo, and t-butyl, could all be well
tolerated. Gratifyingly, the presence of t-butyl functionality on
the aromatic ring caused no effect on the reaction, and the
reaction occurred quite cleanly giving the expected product 3ae
in 69% yield. It was also noticeable that the presence of
substituents in the different positions on the aromatic ring was
perfectly tolerated regardless the ortho-, meta-, para-position
(3aa, 3ad, 3af). Thiol with disubstituted aromatic ring (2g) was
also good substrate for this reaction, which could be transferred
into the corresponding product (3ag) in 60% yield. Arylthiols
with electron-withdrawing groups (CF3, NO2) were found to
give the products, but that they were not sufficiently stable to
be fully characterized.
8
2
9
2
10
11
12
13
14
15
16
17
18
19
2
2
2
1
1.2
1.5
2
i
71
2
33
c
Cu(OAc)2
2
trace
c
FeCl3
2
28
a
b
Reaction conditions: 1a and 2a in CH3CN (2 mL), 24 h. NMR
c
yield, CH2Br2 as an internal standard. 20 mol% amount was used.
d
e
DTBP: di-tert-butyl peroxide. TBHP: tert-butyl hydroperoxide 70%
f
g
aqueous solution. DCP: dicumyl peroxide. BPO: benzoyl peroxide.
With these results in hand, we then focused on exploring the
scope of alkynoates (Scheme 3). As shown in Scheme 3,
starting compounds containing various electron-withdrawing
substituents on the aromatic ring are more affordable. These
substrates reacted quite easily with 4-methylbenzenethiol 2a
and gave the expected products 3ea, 3fa, and 3ja in higher
isolated yields comparing with the results from substrates with
electron-donating groups (3ba, 3da). Of particular interest was
the reaction of alkynoate 1c bearing two substituent groups on
the aromatic ring and this substrate could be easily converted
into the desired product 3ca in 62% yield. Then, we were
interested to investigate the regioselectivity of this reaction by
using the substrates with different substituted aromatic rings on
ester group and alkynyl moiety. All these examined alkynoates
could work very well in this reaction, affording the
corresponding product 3ka-na with up to 80% chemical
yield. However, these reactions showed almost no regioselec-
tivity and the two regio-isomers were obtained in the ratio of
h
i
TBPB: tert-butyl peroxybenzoate. 12 h.
additive (entry 2) could increase the chemical yield to 40%. To
further optimize the reaction condition, several oxidants,
including DTBP (entry 3), TBHP (entry 4), DCP (entry 5),
BPO (entry 6), and TBPB (entry 7), were tried in the reaction.
The reaction could proceed smoothly when it was carried out
in the presence of oxidant DCP, and the highest yield was
found (57%, entry 7). Then, the amount of oxidant DCP was
examined (entries 8−12). We found that the use of 1.0 equiv of
DCP is the best choice, resulting in 79% yield (entry 10).
Continuing the search for optimized conditions we found that
the loading amount of 4-methylbenzenethiol 2a shows obvious
effect on the reaction efficiency. The results from entries 13−15
clearly disclose that 2.0 equiv of 4-methylbenzenethiol 2a is the
best loading. The attempts to improve the yield by varying
reaction time (entry 16) or temperature (entry 17) were not
successful, which suggests 120 °C and 24 h might be the
optimized conditions. Finally, the addition of metal-catalysts,
Cu(OAc)2 and FeCl3 (20 mol%), did not result any
improvement on the reaction (entries 18 and 19).
1
about 1:1 determined by H NMR.
As the final goal in this study, we were interested to know the
reactivity of thiol comparing to disulfide, as disulfide has been
widely used as sulfur radical precursor.17 The reaction of
alkynoate 1a was carried out under the standard condition with
the use of thiol and disulfide as coupling partners (Scheme 4).
With the optimized conditions in hand, we then explored the
substrate scope of the current cascade reaction of phenyl
B
DOI: 10.1021/acs.joc.6b01770
J. Org. Chem. XXXX, XXX, XXX−XXX

The Journal of Organic Chemistry
Note
a,b
indicates that the hydrogen atom came from S−H of thiol.
Then, a control intermediate-trapping experiment with the
addition of the radical-trapping reagents 2,2,6,6-tetramethyl-1-
piperidinyloxy (TEMPO) was carried out (Scheme 5b). The
formation of desired product 3aa was suppressed, and the result
indicates that the transformation may proceed via a radical
course.
Scheme 3. Reaction Scope of Aryl Alkynoates
On the basis of the experiment results above and the
literature reports,15 a possible mechanism of this thiolation
initiated cascade radical reaction is proposed in Scheme 6.
Scheme 6. Proposal Mechanism
a
Reaction conditions: 1 (0.2 mmol), DCP (0.2 mmol), 2a (0.4
mmol), with acetonitrile (2.0 mL) as solvent at 120 °C for 24 h.
b
c
1
Isolated yield. Regioselectivity determined by H NMR.
The reaction afforded the desired products 3aa and 3aa′ with
the ratio of 1:2.63, which indicates disulfide is slightly more
active for the current reaction.
Scheme 4. Reaction with the Use of Thiol and Disulfide as
Coupling Partners
Initially, the aryl sulfur radical A generates from 4-
methylbenzenethiol 2a via S−H bond cleavage under heating
with the aid of oxidant DCP.16b,c Then, intermediate A couples
with alkynoate 1a to give intermediate B. Subsequently, the
intermediate B proceeds through intramolecular spirocycliza-
tion to afford the spiro intermediate C, which undergoes the
aryl migration via cleavage of C−O bond to give the carboxyl
radical D.12h Subsequent decarboxylation of carboxyl radical D
generates intermediate E with the release of CO2. Finally, the
intermediate alkene radical E reacts with 4-methylbenzenethiol
2a to afford the final vinyl sulfide product 3aa along with the
generation of aryl sulfur radical A for the next cycle.
To conclude, thiol as a new radical coupling partner has been
developed for the cascade reaction of aryl alkynoates under
metal-free condition. This radical process has been demon-
strated to proceed through S−H bond cleavage, thiolation of
alkynoate, aryl migration, and decarboxylation. This reaction
was carried out under simple condition and tolerated a wide
range of aryl alkynoates and thiols substrate, to give vinyl
sulfide with good chemical yields. Furthermore, the current
reaction provides a new and efficient access to vinyl sulfides.
To elucidate the experimental results and propose the
mechanism for this reaction, two control experiments were
carried out. First, one reaction with disulfides as sulfur
precursor in D-acetonitrile was performed (Scheme 5a), to
investigate where the acetylenic hydrogen in the product vinyl
sulfide comes from. The reaction afforded 4aa as main product
along with trace number of 3aa′ and [D]-3aa′. This result
Scheme 5. Control Experiments
EXPERIMENTAL SECTION
■
General Procedure for the Cascade Radical Reaction of Aryl
Alkynoates. A sealable reaction tube equipped with a magnetic stirrer
bar was charged with phenyl 3-phenylpropiolate 1a (44.4 mg, 0.2
mmol), DCP (dicumyl peroxide, 0.2 mmol, 54 mg), 4-methylbenze-
nethiol 2a (49.6 mg, 0.4 mmol), and acetonitrile (2.0 mL). The rubber
septum was then replaced by a Teflon−coated screw cap, and the
reaction vessel placed in an oil bath at 120 °C. After stirring the
C
DOI: 10.1021/acs.joc.6b01770
J. Org. Chem. XXXX, XXX, XXX−XXX

The Journal of Organic Chemistry
Note
mixture at this temperature for 24 h, it was cooled to room
temperature and diluted with ethyl acetate, washed with water, dried
over MgSO4. After the solvent was removed under reduced pressure,
the residue was purified by column chromatography on silica gel
(elute: hexane) to afford the corresponding product 3aa in 76% yield.
(2,2-Diphenylvinyl)(p-tolyl)sulfane (3aa).18 White solid. mp 86−
(2,2-Bis(3,4-dimethylphenyl)vinyl)(p-tolyl)sulfane (3ca). Colorless
oil. Yield: 44.4 mg (62%). H NMR (400 MHz, CDCl3) δ 7.36−7.29
1
(m, 2H), 7.17 (d, J = 8.2 Hz, 1H), 7.15−7.07 (m, 4H), 7.05−7.00 (m,
2H), 6.97 (dd, J = 7.8, 2.0 Hz, 1H), 6.70 (s, 1H), 2.33 (s, 3H), 2.29 (s,
3H), 2.27 (s, 3H), 2.23 (s, 3H), 2.21 (s, 3H). 13C NMR (101 MHz,
CDCl3) δ 140.8, 139.5, 136.9, 136.7, 136.5, 136.4, 136.1, 135.7, 133.3,
130.8, 129.9, 129.8, 129.6, 129.5, 128.4, 127.3, 124.8, 123.3, 21.1, 19.9,
19.9, 19.7, 19.5. IR (Attenuated total reflection, cm−1): 1491, 1447,
1264, 1091, 1017, 890, 803, 736. HRMS (TOF MS EI+) m/z calcd for
[C25H26S] 358.1755, found 358.1764.
1
88 °C. Yield: 45.9 mg (76%). H NMR (400 MHz, CDCl3) δ 7.45−
7.39 (m, 2H), 7.38−7.31 (m, 5H), 7.30−7.20 (m, 5H), 7.14 (d, J = 7.9
Hz, 2H), 6.82 (s, 1H), 2.34 (s, 3H). 13C NMR (101 MHz, CDCl3) δ
141.6, 140.2, 139.3, 137.0, 132.8, 130.1, 129.9, 129.8, 128.4, 128.3,
127.8, 127.2, 125.3, 21.1. IR (Attenuated total reflection, cm−1): 1583,
1490, 1441, 1333, 1265, 1094, 1073, 1030, 941, 904. HRMS (TOF MS
EI+) m/z calcd for [C21H18S] 302.1129, found 302.1131.
(2,2-Bis(3-methoxyphenyl)vinyl)(p-tolyl)sulfane (3da). Colorless
1
oil. Yield: 40.6 mg (56%). H NMR (400 MHz, CDCl3) δ 7.38−7.29
(m, 3H), 7.23−7.10 (m, 3H), 6.99−6.73 (m, 7H), 3.81 (s, 3H), 3.75
(s, 3H), 2.34 (s, 3H). 13C NMR (101 MHz, CDCl3) δ 159.6, 159.5,
142.8, 140.5, 139.5, 137.1, 132.8, 130.2, 129.9, 129.4, 129.2, 125.8,
122.2, 119.8, 115.1, 113.5, 113.1, 112.3, 55.3, 55.3, 21.1. IR
(Attenuated total reflection, cm−1): 1381, 1088, 1045, 879, 585.
HRMS (TOF MS EI+) m/z calcd for [C23H22O2S] 362.1341, found
362.1347.
(4-Bromophenyl)(2,2-diphenylvinyl)sulfane (3ab). White solid.
1
mp 90−92 °C. Yield: 38.2 mg (52%). H NMR (400 MHz, CDCl3)
δ 7.39−7.32 (m, 4H), 7.31−7.28 (m, 1H), 7.28−7.24 (m, 2H), 7.23−
7.15 (m, 7H), 6.70 (s, 1H). 13C NMR (101 MHz, CDCl3) δ 142.2,
141.2, 139.0, 135.8, 132.2, 130.9, 129.7, 128.5, 128.4, 128.0, 127.6,
127.3, 123.0, 120.7. IR (Attenuated total reflection, cm−1): 1471, 1441,
1090, 1083, 1001, 811, 769. HRMS (TOF MS EI+) m/z calcd for
[C20H1579BrS] 366.0078, found 366.0070.
(2,2-Bis(3-fluorophenyl)vinyl)(p-tolyl)sulfane (3ea). Colorless oil.
Yield: 45.3 mg (67%). 1H NMR (400 MHz, CDCl3) δ 7.44−7.31 (m,
3H), 7.26−7.19 (m, 1H), 7.19−7.11 (m, 3H), 7.10−7.02 (m, 2H),
7.01−6.84 (m, 4H), 2.35 (s, 3H). 13C NMR (101 MHz, CDCl3) δ
164.1 (1JCF = 247.4 Hz), 143.2, 143.1, 140.8, 140.8, 137.6, 137.1,
137.0, 137.0, 132.0, 130.6, 130.2 (3JCF = 9.0 Hz), 129.8, 129.8, 128.2,
125.5 (4JCF = 3.0 Hz), 122.7, 122.7, 116.8 (2JCF = 21.2 Hz), 115.1,
114.8, 114.2, 114.0, 114.0, 113.8, 21.1. IR (Attenuated total reflection,
cm−1): 1429, 1379, 1088, 1045, 879, 806, 769. HRMS (TOF MS EI+)
m/z calcd for [C21H16F2S] 338.0941, found 338.0939.
(4-Chlorophenyl)(2,2-diphenylvinyl)sulfane (3ac). Yellow oil.
1
Yield: 38.6 mg (60%). H NMR (400 MHz, CDCl3) δ 7.44−7.39
(m, 2H), 7.38−7.32 (m, 5H), 7.30−7.23 (m, 7H), 6.77 (s, 1H). 13C
NMR (101 MHz, CDCl3) δ 142.0, 141.3, 139.0, 135.1, 132.8, 130.7,
129.7, 129.3, 128.5, 128.4, 128.0, 127.5, 127.3, 123.2. IR (Attenuated
total reflection, cm−1): 1587, 1475, 1388, 1091, 984, 939, 823. HRMS
(TOF MS EI+) m/z calcd for [C20H1535ClS] 322.0583, found
322.0587.
(2,2-Diphenylvinyl)(o-tolyl)sulfane (3ad). Yellow oil. Yield: 37.4
mg (62%). 1H NMR (400 MHz, CDCl3) δ 7.49−7.46 (m, 1H), 7.45−
7.41 (m, 1H), 7.41−7.38 (m, 2H), 7.37−7.34 (m, 1H), 7.30−7.13 (m,
9H), 6.74 (s, 1H), 2.37 (s, 3H). 13C NMR (101 MHz, CDCl3) δ
141.6, 141.4, 139.3, 138.3, 135.7, 130.4, 130.3, 129.8, 128.4, 128.3,
127.8, 127.3, 127.2, 127.1, 126.7, 124.3, 20.7. IR (Attenuated total
reflection, cm−1): 1379, 1087, 1046, 880, 589, 579. HRMS (TOF MS
EI+) m/z calcd for [C21H18S] 302.1129, found 302.1134.
(2,2-Bis(3-chlorophenyl)vinyl)(p-tolyl)sulfane (3fa). White solid.
mp 120−122 °C. Yield: 53.2 mg (72%). 1H NMR (400 MHz, CDCl3)
δ 7.41−7.30 (m, 5H), 7.29−7.12 (m, 6H), 7.10−7.01 (m, 1H), 6.85 (s,
1H), 2.35 (s, 3H). 13C NMR (101 MHz, CDCl3) δ 142.8, 140.4,
137.7, 136.7, 134.5, 134.4, 131.9, 130.6, 130.1, 129.9, 129.7, 129.6,
128.5, 128.2, 128.0, 127.3, 127.0, 125.2, 21.1. IR (Attenuated total
reflection, cm−1): 1559, 1465, 1402, 1077, 959, 837, 816, 801. HRMS
(TOF MS EI+) m/z calcd for [C21H1635Cl2S] 370.0350, found
370.0353.
(2,2-Di-p-tolylvinyl)(p-tolyl)sulfane (3ga). White solid. mp 119−
121 °C. Yield: 46.9 mg (71%). 1H NMR (400 MHz, CDCl3) δ 7.36−
7.30 (m, 2H), 7.27−7.19 (m, 4H), 7.16−7.10 (m, 4H), 7.07 (d, J = 8.1
Hz, 2H), 6.73 (s, 1H), 2.39 (s, 3H), 2.33 (s, 3H), 2.32 (s, 3H). 13C
NMR (101 MHz, CDCl3) δ 140.5, 139.0, 137.5, 137.0, 136.8, 136.5,
133.2, 129.9, 129.9, 129.7, 129.1, 129.0, 127.2, 123.6, 21.4, 21.2, 21.1.
IR (Attenuated total reflection, cm−1): 1586, 1510, 1492, 1181, 1112,
829, 815. HRMS (TOF MS EI+) m/z calcd for [C23H22S] 330.1442,
found 330.1441.
(2,2-Bis(4-chlorophenyl)vinyl)(p-tolyl)sulfane (3ha). White solid.
mp 103−105 °C. Yield: 42.3 mg (57%). 1H NMR (400 MHz, CDCl3)
δ 7.39 (dt, 2H), 7.33 (dt, 2H), 7.28 (dt, 2H), 7.25−7.21 (m, 2H),
7.18−7.10 (m, 4H), 6.80 (s, 1H), 2.35 (s, 3H). 13C NMR (101 MHz,
CDCl3) δ 139.7, 137.5, 137.4, 137.2, 133.8, 133.2, 132.1, 131.2, 130.4,
130.1, 128.8, 128.6, 128.3, 126.9, 21.1. IR (Attenuated total reflection,
cm−1): 1485, 1393, 1088, 1014, 929, 810, 727. HRMS (TOF MS EI+)
m/z calcd for [C21H1635Cl2S] 370.0350, found 370.0355.
(4-(tert-Butyl)phenyl)(2,2-diphenylvinyl)sulfane (3ae). Light yel-
1
low oil. Yield: 47.5 mg (69%). H NMR (400 MHz, CDCl3) δ 7.44−
7.32 (m, 9H), 7.29−7.21 (m, 5H), 6.85 (s, 1H), 1.31 (s, 9H). 13C
NMR (101 MHz, CDCl3) δ 150.2, 141.6, 140.2, 139.3, 132.9, 129.8,
129.8, 128.4, 128.3, 127.8, 127.2, 126.2, 125.2, 34.6, 31.3. IR
(Attenuated total reflection, cm−1): 1490, 1441, 1393, 1336, 1266,
1119, 1071, 1013. HRMS (TOF MS EI+) m/z calcd for [C24H24S]
344.1599, found 344.1592.
(2,2-Diphenylvinyl)(m-tolyl)sulfane (3af). Yellow oil. Yield: 34.4
mg (57%). 1H NMR (400 MHz, CDCl3) δ 7.45−7.39 (m, 2H), 7.38−
7.32 (m, 3H), 7.31−7.18 (m, 8H), 7.08−7.02 (m, 1H), 6.86 (s, 1H),
2.34 (s, 3H). 13C NMR (101 MHz, CDCl3) δ 141.6, 140.8, 139.3,
139.0, 136.2, 130.2, 129.8, 129.0, 128.4, 128.3, 127.8, 127.7, 127.3,
127.2, 126.7, 124.4, 21.4. IR (Attenuated total reflection, cm−1): 1592,
1494, 1441, 940, 770, 753. HRMS (TOF MS EI+) m/z calcd for
[C21H18S] 302.1129, found 302.1130.
(3,4-Dimethylphenyl)(2,2-diphenylvinyl)sulfane (3ag). Colorless
1
oil. Yield: 38.2 mg (60%). H NMR (400 MHz, CDCl3) δ 7.46−7.33
(m, 5H), 7.30−7.16 (m, 7H), 7.09 (d, J = 7.8 Hz, 1H), 6.83 (s, 1H),
2.24 (s, 3H), 2.24 (s, 3H). 13C NMR (101 MHz, CDCl3) δ 141.6,
139.9, 139.3, 137.7, 135.8, 133.0, 131.4, 130.4, 129.8, 128.4, 128.3,
127.8, 127.7, 127.2, 127.2, 125.6, 19.8, 19.5. IR (Attenuated total
reflection, cm−1): 1597, 1494, 1442, 905, 811, 727, 697. HRMS (TOF
MS EI+) m/z calcd for [C22H20S] 316.1286, found 316.1281.
(2,2-Di-m-tolylvinyl)(p-tolyl)sulfane (3ba). Yellow oil. Yield: 41.6
mg (63%). 1H NMR (400 MHz, CDCl3) δ 7.37−7.27 (m, 3H), 7.20−
7.10 (m, 6H), 7.08−7.00 (m, 3H), 6.78 (s, 1H), 2.37 (s, 3H), 2.33 (s,
3H), 2.29 (s, 3H). 13C NMR (101 MHz, CDCl3) δ 141.6, 140.5,
139.3, 138.0, 137.9, 136.9, 133.0, 130.3, 130.1, 129.9, 128.5, 128.2,
128.2, 128.0, 127.8, 126.9, 124.9, 124.4, 21.6, 21.5, 21.1. IR
(Attenuated total reflection, cm−1): 1601, 1490, 1092, 1017, 840,
804, 779, 758, 714. HRMS (TOF MS EI+) m/z calcd for [C23H22S]
330.1442, found 330.1439.
(2,2-Bis(4-bromophenyl)vinyl)(p-tolyl)sulfane (3ia). White solid.
mp 131−133 °C. Yield: 55.9 mg (61%). 1H NMR (400 MHz, CDCl3)
δ 7.54−7.40 (m, 2H), 7.38−7.36 (m, 2H), 7.32−7.24 (m, 2H), 7.21−
7.19 (m, 2H), 7.18−7.12 (m, 2H), 7.06−7.04 (m, 2H), 6.81 (s, 1H),
2.34 (s, 3H). 13C NMR (101 MHz, CDCl3) δ 140.1, 137.6, 137.6,
137.4, 132.0, 131.8, 131.5, 131.5, 130.4, 130.1, 128.7, 127.1, 122.0,
121.4, 21.1. IR (Attenuated total reflection, cm−1): 1488, 1392, 1067,
1011, 1006, 929, 807. HRMS (TOF MS EI+) m/z calcd for
[C21H1679Br2S] 457.9339, found 457.9340.
(2,2-Bis(4-fluorophenyl)vinyl)(p-tolyl)sulfane (3ja). White solid.
mp 110−112 °C. Yield: 46.1 mg (68%). 1H NMR (400 MHz, CDCl3)
δ 7.37−7.26 (m, 4H), 7.22−7.05 (m, 6H), 7.00−6.91 (m, 2H), 6.73 (s,
1H), 2.34 (s, 3H). 13C NMR (101 MHz, CDCl3) δ 163.5 (1JCF = 248.4
Hz), 138.1, 137.7, 137.7, 137.3, 136.6, 135.0, 135.0, 132.4, 131.6 (3JCF
= 8.0 Hz), 130.2, 130.0, 129.1, 128.8, 128.7, 127.9, 126.6, 126.5, 125.5,
D
DOI: 10.1021/acs.joc.6b01770
J. Org. Chem. XXXX, XXX, XXX−XXX

The Journal of Organic Chemistry
Note
115.6 (2JCF = 21.2 Hz), 21.1. IR (Attenuated total reflection, cm−1):
1501, 1232, 1217, 1155, 844, 815, 784. HRMS (TOF MS EI+) m/z
calcd for [C21H16F2S] 338.0941, found 338.0937.
ACKNOWLEDGMENTS
■
We gratefully acknowledge the financial support from the
National Natural Science Foundation of China (Nos. 21102071
and 21472082). The Jiangsu 333 program (for Pan) and
Changzhou Jin-Feng-Huang program (for Han) are also
acknowledged.
(2-(4-Fluorophenyl)-2-phenylvinyl)(p-tolyl)sulfane (3ka). White
1
solid. mp 89−91 °C. Yield: 49.2 mg (77%). H NMR (400 MHz,
CDCl3) δ 7.45−7.39 (m, 1H), 7.37−7.31 (m, 4H), 7.30−7.16 (m,
4H), 7.16−7.03 (m, 3H), 6.99−6.92 (m, 1H), 6.80 (s, 0.45H), 6.74 (s,
0.49H), 2.34 (s, 3H). 13C NMR (101 MHz, CDCl3) δ 163.4 (1JCF
=
248.4 Hz), 146.5, 141.4, 139.1, 139.1, 138.7, 137.8, 137.8, 137.2, 137.2,
136.6, 135.2, 135.1, 132.7, 132.5, 131.6, 131.6, 130.2, 130.2, 130.0,
130.0, 129.7, 129.1, 128.8, 128.8, 128.5, 128.4, 127.9, 127.9, 127.3,
127.1, 126.6, 126.5, 125.6, 125.2, 125.2, 115.5 (2JCF = 21.2 Hz), 21.1.
IR (Attenuated total reflection, cm−1): 1599, 1505, 1491, 1220, 1156,
1017, 933. HRMS (TOF MS EI+) m/z calcd for [C21H17FS] 320.1035,
found 320.1042.
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1
solid. mp 55−57 °C. Yield: 41.1 mg (61%). H NMR (400 MHz,
CDCl3) δ 7.46−7.27 (m, 7H), 7.26−7.18 (m, 3H), 7.18−7.11 (m,
3H), 6.81 (s, 0.43H), 6.80 (s, 0.47H), 2.34 (s, 3H). 13C NMR (101
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133.6, 132.97, 132.5, 132.4, 131.25, 130.3, 130.2, 130.0, 129.7, 128.7,
128.5, 128.5, 128.4, 128.4, 128.0, 127.4, 127.2, 126.2, 126.0, 21.1. IR
(Attenuated total reflection, cm−1): 1490, 1441, 1397, 1090, 1009, 945,
936, 806, 775. HRMS (TOF MS EI+) m/z calcd for [C21H1735ClS]
336.0740, found 336.0738.
(2-(4-Bromophenyl)-2-phenylvinyl)(p-tolyl)sulfane (3ma). Light
1
yellow solid. mp 70−72 °C. Yield: 42.6 mg (56%). H NMR (400
MHz, CDCl3) δ 7.57−7.51 (m, 1H), 7.43−7.31 (m, 6H), 7.26−7.19
(m, 3H), 7.14 (d, J = 7.9 Hz, 2H), 7.11−7.06 (m, 1H), 6.81 (s,
0.47H), 6.81 (s, 0.52H), 2.34 (s, 3H). 13C NMR (101 MHz, CDCl3) δ
141.2, 140.5, 138.9, 138.7, 138.7, 138.2, 137.3, 137.3, 136.6, 132.5,
132.4, 131.6, 131.6, 131.4, 130.4, 130.2, 130.0, 129.7, 129.1, 128.7,
128.6, 128.4, 128.4, 128.0, 127.9, 127.4, 127.2, 126.6, 126.4, 126.0,
121.8, 121.1, 21.1. IR (Attenuated total reflection, cm−1): 1491, 1442,
1090, 1045, 1010, 880, 804, 698. HRMS (TOF MS EI+) m/z calcd for
[C21H17BrS] 380.0234, found 380.0236.
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(2-(3-Bromophenyl)-2-phenylvinyl)(p-tolyl)sulfane (3na). Color-
1
less oil. Yield: 60.8 mg (80%). H NMR (400 MHz, CDCl3) δ 7.53−
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0.44H), 6.82 (s, 0.50H), 2.34 (s, 3H). 13C NMR (101 MHz, CDCl3) δ
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1
solid. mp 98−100 °C. Yield: 39.6 mg (50%). H NMR (400 MHz,
CDCl3) δ 7.33−7.22 (m, 10H), 7.20−7.15 (m, 6H), 7.15−7.10 (m,
4H). 13C NMR (101 MHz, CDCl3) δ 151.9, 142.1, 134.8, 131.2, 129.5,
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ASSOCIATED CONTENT
■
S
* Supporting Information
The Supporting Information is available free of charge on the
ACS Publications website at DOI: 10.1021/acs.joc.6b01770.
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Full spectroscopic data for compounds 3 and 4aa and
1
copies of H and 13C NMR spectra (PDF)
AUTHOR INFORMATION
■
́
Artigas, M. J.; Polo, V.; Lahoz, F. J.; Castarlenas, R.; Perez-Torrente, J.
J.; Oro, L. A. ACS Catal. 2013, 3, 2910−2919. (d) Riduan, S. N.; Ying,
J. Y.; Zhang, Y. Org. Lett. 2012, 14, 1780−1783. (e) Yang, Y.; Rioux, R.
M. Chem. Commun. 2011, 47, 6557−6559. (f) Sarma, R.; Rajesh, N.;
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Frech, C. M. Chem. - Eur. J. 2012, 18, 8901−8905. (h) Di Giuseppe,
Corresponding Author
*E-mail: hanjl@nju.edu.cn
Notes
The authors declare no competing financial interest.
E
DOI: 10.1021/acs.joc.6b01770
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The Journal of Organic Chemistry
Note
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F
DOI: 10.1021/acs.joc.6b01770
J. Org. Chem. XXXX, XXX, XXX−XXX