A Mild and Rapid Synthesis of (Z)-β-Sulfonyl Enoates from Sodium Sulfinates and Propargyl Esters

Article abstract of DOI:10.1002/cjoc.201600429

Water-promoted sulfonylation of propargyl esters leading to highly regioselective and stereoselective formation of (Z)-β-sulfonyl enoates in excellent yields, by a simple, mild, rapid and environmentally benign reaction procedure is reported.

Full text of DOI:10.1002/cjoc.201600429

FULL PAPER
DOI: 10.1002/cjoc.201600429
A Mild and Rapid Synthesis of (Z)-β-Sulfonyl Enoates from
Sodium Sulfinates and Propargyl Esters
Jun Jiang,a Huaxu Zou,a Niannian Yi,a Ruijia Wang,a Hao Zhang,a Lixin Lan,*,b
and Jiannan Xiang*,a
a State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering,
Hunan University, Changsha, Hunan 410082, China
b Hunan Chemical Vocational Technology College, Zhuzhou, Hunan 412000, China
Water-promoted sulfonylation of propargyl esters leading to highly regioselective and stereoselective formation
of (Z)-β-sulfonyl enoates in excellent yields, by a simple, mild, rapid and environmentally benign reaction proce-
dure is reported.
Keywords sodium sulfinates, propargyl esters, green reaction, (Z)-β-sulfonyl enoates
Introduction
synthetic sequences.[8] Taking the significance of sul-
fur-containing organic compounds and related scaffolds
into account,[9] and following our interest in functional-
ization of alkyne,[10] we exploited an efficient sulfonyla-
tion of propargyl esters with sodium sulfinates to afford
(Z)-β-sulfonyl enoates via an anion process (Scheme 1e).
These conversions can be easily completed in water
under green reaction conditions. These transformations
did not involve any catalyst, ligand, or organic solvent.
β-Sulfonyl enoates are present in many bioactive
molecules and serve as useful building blocks in organic
synthesis.[1] The significance of sulfones and the diffi-
culties in their preparation have gained intensive atten-
tion (Scheme 1). Traditionally, β-sulfonyl enoates were
prepared by the reaction of cross-coupling of organos-
tannanes with sulfonyl chlorides,[2] iodosulphonylation-
dehydroiodination (Scheme 1a)[3] or imines with ethyl
propiolate (Scheme 1b).[4] Recently, a sulfonylation us-
ing sodium arylsulfinates of alkyl propiolates leading to
(E)-β-sulfonyl enoates in DMF was reported by Khalili
(Scheme 1c).[5] Moreover, a two-step thioconjugate ad-
dition-oxidation reaction of ethyl propiolates with nu-
merous types of thiols and meta-chloroperbenzoic acids
(m-CPBA) in the presence of LiClO4 leading to
(Z)-β-sulfonyl enoates was reported (Scheme 1d).[6]
However, a majority of them employed a catalyst, an
addition agent or a toxic organic solvent and proceeded
via two steps. However, these methods present several
limitations, such as the use of expensive NHC catalyst,
requiring hazardous chemicals and multi-step proce-
dures, occurrence of side reactions, etc. In particular,
few researches that refer to the mild and rapid synthesis
of (Z)-β-sulfonyl enoates were reported. In consequence,
there is still an urgent need for the exploitation of milder
and more rapid synthetic method of (Z)-β-sulfonyl eno-
ates.
Experimental
Commercially available reagents were of reagent
grade (AR grade) and were used without further purifi-
cation. Reactions were monitored by thin layer chroma-
tography (TLC) using silicycle pre-coated silica gel
plates. Flash column chromatography was performed
1
over silicycle silica gel (200－300 mesh). H NMR and
13C NMR spectra were recorded on 400 MHz NMR plus
spectrometer using residue solvent peaks as internal
standards. Infrared spectra were recorded with IR spec-
trometer and are reported in reciprocal centimeter
(cm1). High resolution mass spectra were obtained us-
ing GCT-TOF instrument with ESI source. Sulfonyl
hydrazides and propargyl esters except ethyl propiolate,
methyl propiolate were prepared according to literature
procedures. Rest of the chemicals were purchased from
Sigma Aldrich and Alfa Aesar, and were used without
further purification. Solvents were purified by standard
methods.
Water, as a proton source, is the best solvent for or-
ganic synthesis for its natural, inexpensive, and envi-
ronmentally friendly characteristics.[7] Besides, alkynes,
as versatile structural motif, are extensively employed in
General procedure of 3
A mixture of sodium sulfinate (0.25 mmol),
*
E-mail: jnxiang@hnu.edu.cn
Received July 13, 2016; accepted October 23, 2016; published online December 20, 2016.
Supporting information for this article is available on the WWW under http://dx.doi.org/10.1002/cjoc.201600429 or from the author.
Chin. J. Chem. 2016, 34, 1245—1250
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Jiang et al.
FULL PAPER
Scheme 1 (a) lodosulphonylation-dehydroiodination leading to
(E)-b-sulfonyl enoates; (b) imines with ethyl propiolate; (c) sul-
fonylation using sodium arylsulfinate of alkyl propiolate leading
to (E)-b-sulfonyl enoates; (d) two-step thioconjugate addition-
oxidation reaction of ethyl propiolate; (e) catalyst-free sulfonyla-
tion of propargyl esters
2H), 6.49 (ABq, ΔδAB＝0.03, JAB＝10.0 Hz, 2H), 4.33
(q, J＝7.1 Hz, 2H), 1.35 (t, J＝7.1 Hz, 3H); 13C NMR
(101 MHz, CDCl3) δ: 164.20, 139.69, 135.39, 134.28,
132.18, 129.56, 128.45, 62.44, 14.21. The data meet the
literature report.[6]
(Z)-Ethyl 3-((4-methoxyphenyl)sulfonyl)acrylate
(3ca) White solid; yield 98% (66.2 mg); m.p. 76 ℃
Previous work:
(1) I2, CH2Cl2
1
(Lit. m.p. 75－77 ℃); H NMR (400 MHz, CDCl3) δ:
CO2R
ArSHO2Na
+
7.89 (d, J＝8.8 Hz, 2H), 6.99 (d, J＝8.8 Hz, 2H), 6.44
(ABq, ΔδAB＝0.06, JAB＝12.0 Hz, 2H), 4.33 (q, J＝7.1
Hz, 2H), 3.85 (s, 3H), 1.35 (t, J＝7.1 Hz, 3H); 13C NMR
(101 MHz, CDCl3) δ: 164.30, 164.27, 135.82, 131.03,
130.74, 114.71, 62.26, 55.86, 14.14. The data meet the
literature report.[6]
(2) Et3N, CH2Cl2
SO2Ar
(a)
RO2C
NHC, DBU
CO2R
+
Ph
NTs
PhMe, 70 oC
(Z)-Ethyl
3-((4-fluorophenyl)sulfonyl)acrylate
Ts
CO2R
(3da) White solid; yield 94% (60.6 mg); m.p. 53 ℃
(b)
(c)
1
(Lit. m.p. 52－53 ℃); H NMR (400 MHz, CDCl3) δ:
8.05 (dd, J＝8.8, 5.1 Hz, 2H), 7.25 (d, J＝8.1 Hz, 2H),
6.52 (s, 2H), 4.36 (q, J＝7.1 Hz, 2H), 1.38 (t, J＝7.1 Hz,
3H); 13C NMR (101 MHz, CDCl3) δ: 167.45, 164.89,
163.99, 135.63, 135.28, 132.29, 131.42, 131.33, 116.87,
116.65, 62.37, 14.08. The data meet the literature re-
port.[6]
(1) DMF, 24 h, r.t.
(2) H2O
CO2R
ArSHO2Na
RO2C
+
SO2Ar
(Z)-Ethyl
3-((4-chlorophenyl)sulfonyl)acrylate
(1) i-Pr2NEt, CH2Cl2, -78 oC
(2) mCPBA, LiClO4
SH
+
CO2R2
CO2R2
(3ea) White solid; yield 93% (63.7 mg); m.p. 55 ℃
(Lit. m.p. 54－56 ℃); H NMR (400 MHz, CDCl3) δ:
R1
1
R1O2S
7.94 (d, J＝8.6 Hz, 2H), 7.52 (d, J＝8.5 Hz, 2H), 6.50
(s, 2H), 4.34 (q, J＝7.3 Hz, 1H), 1.36 (t, J＝7.2 Hz, 2H);
13C NMR (101 MHz, CDCl3) δ: 163.82, 140.93, 137.98,
135.05, 132.53, 129.81, 129.68, 62.32, 14.00; IR (neat)
v: 2992, 1984, 1794, 1602, 1549, 1347, 1050 cm1;
HRMS calcd for C11H11ClO4S (M＋Na＋): 296.9964,
found 296.9965.
(d)
This work:
R1SO2Na
H2O, H2SO4
CO2R2
+
60 oC, 10 min
R1O2S
CO2R2
(e)
(Z)-Ethyl
3-((4-bromophenyl)sulfonyl)acrylate
(3fa) White solid; yield 95% (75.5 mg); m.p. 56 ℃
(Lit. m.p. 55－57 ℃); H NMR (400 MHz, CDCl3) δ:
propargyl esters (0.75 mmol) and 0.025 mmol of H2SO4
in water (2 mL) was put into an oil bath at 80 ℃ under
magnetic stirring for 10 min under air. After the reaction
was complete, the mixture was added 20 mL of water
and extracted with EtOAc (3×15 mL) and then the
combined organic extract was washed with brine (15
mL), dried over sodium sulfate, and filtered. The solvent
was removed under reduced pressure and the residue
was purified by chromatography on silica gel with pe-
troleum ether/ethyl acetate as eluent to afford the corre-
sponding product.
1
7.85 (d, J＝8.4 Hz, 2H), 7.69 (d, J＝8.4 Hz, 2H), 6.50
(s, 2H), 4.34 (q, J＝7.1 Hz, 2H), 1.36 (t, J＝7.2 Hz, 3H);
13C NMR (101 MHz, CDCl3) δ: 163.80, 138.51, 135.01,
132.67, 132.56, 129.84, 129.55, 62.31, 13.99. The data
meet the literature report.[6]
(Z)-Ethyl 3-(m-tolylsulfonyl)acrylate (3ga) Col-
1
orless oil; yield 97% (61.6 mg); H NMR (400 MHz,
CDCl3) δ: 7.78－7.74 (m, 2H), 7.42 (t, J＝4.0 Hz, 2H),
6.48 (ABq, ΔδAB＝0.03, JAB＝10.0 Hz, 2H), 4.33 (q,
J＝7.1 Hz, 2H), 2.42 (s, 3H), 1.36 (t, J＝7.1 Hz, 3H);
13C NMR (101 MHz, CDCl3) δ: 162.99, 138.62, 138.26,
134.13, 133.82, 130.65, 128.18, 127.42, 124.31, 61.13,
20.30, 12.96; IR (neat) v: 1985, 1796, 1601, 1548, 1348,
1051 cm1; HRMS calcd for C12H14O4S (M＋Na＋):
277.0510, found 277.0514.
(Z)-Ethyl 3-tosylacrylate (3aa) White solid; yield
1
96% (61.0 mg); m.p. 37 ℃ (Lit. m.p. 36－38 ℃); H
NMR (400 MHz, CDCl3) δ: 7.83 (d, J＝8.1 Hz, 2H),
7.32 (d, J＝8.0 Hz, 2H), 6.45 (ABq, ΔδAB＝0.04, JAB
＝
12.0 Hz, 2H), 4.32 (q, J＝7.1 Hz, 2H), 2.38 (s, 3H),
1.34 (t, J＝7.1 Hz, 3H); 13C NMR (101 MHz, CDCl3) δ:
164.16, 145.30, 136.60, 135.51, 131.52, 130.06, 128.38,
62.25, 21.79, 14.08. The data meet the literature re-
port.[6]
(Z)-Ethyl
3-((3-bromophenyl)sulfonyl)acrylate
(3ha) White solid; yield 94% (74.7 mg); m.p. 47 ℃
1
(Lit. m.p. 47－48 ℃); H NMR (400 MHz, CDCl3) δ:
8.13 (t, J＝1.9 Hz, 1H), 7.92 (d, J＝8.0 Hz, 1H), 7.76 (d,
J＝8.0 Hz, 1H), 7.43 (t, J＝7.9 Hz, 1H), 6.53 (ABq,
ΔδAB＝0.03, JAB＝12.0 Hz, 2H), 4.35 (q, J＝7.2 Hz,
2H), 1.37 (t, J＝7.1 Hz, 3H); 13C NMR (101 MHz,
(Z)-Ethyl
3-(phenylsulfonyl)acrylate
(3ba)
White solid; yield 93% (55.8 mg); m.p. 70 ℃ (Lit. m.p.
69－71 ℃); H NMR (400 MHz, CDCl3) δ: 7.97 (d,
J＝8.1 Hz, 2H), 7.68－7.58 (m, 1H), 7.54 (t, J＝7.6 Hz,
1
1246
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Chin. J. Chem. 2016, 34, 1245—1250

A Mild and Rapid Synthesis of (Z)-β-Sulfonyl Enoates from Sodium Sulfinates and Propargyl Esters
1
CDCl3) δ: 163.69, 141.35, 137.10, 134.69, 132.93,
131.13, 130.85, 126.83, 123.25, 62.37, 13.98; IR (neat)
v: 2990, 1983, 1795, 1601, 1548, 1346, 1052 cm1;
HRMS calcd for C11H11BrO4S (M＋Na＋): 340.9459,
found 340.9459.
(Z)-Ethyl 3-(o-tolylsulfonyl)acrylate (3ia) White
solid; yield 95% (60.3 mg); m.p. 56 ℃ (Lit. m.p. 55－
56 ℃); 1H NMR (400 MHz, CDCl3) δ: 8.03 (d, J＝8.0,
1H), 7.50 (t, J＝8.0 Hz, 1H), 7.36 (t, J＝7.7 Hz, 1H),
7.30 (d, J＝7.6 Hz, 1H), 6.58 (d, J＝11.7 Hz, 1H), 6.48
(d, J＝11.7 Hz, 1H), 4.26 (q, J＝7.2 Hz, 2H), 2.63 (s,
3H), 1.31 (t, J＝7.1 Hz, 3H); 13C NMR (101 MHz,
CDCl3) δ: 163.63, 138.53, 137.90, 135.75, 134.11,
132.68, 131.67, 129.86, 126.65, 62.18, 20.40, 14.00; IR
(neat) v: 1984, 1796, 1603, 1549, 1347, 1050 cm1;
HRMS calcd for C12H14O4S (M＋Na＋ ): 277.0510,
found 277.0512.
yield 82% (49.2 mg); H NMR (400 MHz, CDCl3) δ:
7.86 (d, J＝8.2 Hz, 2H), 7.36 (d, J＝8.0 Hz, 2H), 6.50
(ABq, ΔδAB＝0.06, JAB＝12.0 Hz, 2H), 3.89 (s, 3H),
2.45 (s, 3H); 13C NMR (101 MHz, CDCl3) δ: 164.53,
145.30, 136.42, 135.91, 131.05, 130.02, 128.31, 52.78,
21.72; IR (neat) v: 1984, 1795, 1601, 1548, 1347, 1050
cm1; HRMS calcd for C11H12O4S (M＋Na＋): 263.0354,
found 263.0355.
(Z)-Phenyl 3-tosylacrylate (3ac) Yellow solid;
yield 76% (57.4 mg); m.p. 86 ℃ (Lit. m.p. 85－
87 ℃); H NMR (400 MHz, CDCl3) δ: 7.90 (d, J＝8.1
Hz, 2H), 7.48－7.42 (m, 2H), 7.38－7.28 (m, 5H), 6.67
(ABq, ΔδAB＝0.03, JAB＝12.0 Hz, 2H), 2.45 (s, 3H);
13C NMR (101 MHz, CDCl3) δ: 162.79, 150.06, 145.43,
136.21, 130.51, 130.08, 129.62, 128.42, 126.47, 121.56,
21.69; IR (neat) v: 1984, 1791, 1601, 1549, 1542, 1348,
1052 cm1; HRMS calcd for C16H14O4S (M＋Na＋):
325.0510, found 325.0493.
1
(Z)-Ethyl
3-((2-bromophenyl)sulfonyl)acrylate
(3ja) White solid; yield 91% (72.3 mg); m.p. 47 ℃
(Lit. m.p. 46－48 ℃); H NMR (400 MHz, CDCl3) δ:
(Z)-Benzyl 3-tosylacrylate (3ad) White solid;
yield 75% (59.3 mg); m.p. 103 ℃ (Lit. m.p. 102－
103 ℃); 1H NMR (400 MHz, CDCl3) δ: 7.73 (d, J＝8.1
Hz, 2H), 7.40－7.26 (m, 5H), 7.21 (d, J＝8.0 Hz, 2H),
6.43 (ABq, ΔδAB＝0.04, JAB＝12.0 Hz, 2H), 5.22 (s,
2H), 2.35 (s, 3H); 13C NMR (101 MHz, CDCl3) δ:
163.89, 145.22, 136.38, 135.86, 134.76, 131.01, 129.94,
128.92, 128.68, 128.65, 128.35, 68.03, 21.70; IR (neat)
v: 2996, 1985, 1794, 1602, 1549, 1541, 1348, 1052 cm1;
HRMS calcd for C17H16O4S (M + Na+): 339.0667,
found 339.0671.
1
8.19 (dd, J＝7.8, 1.8 Hz, 1H), 7.73 (d, J＝7.8 Hz, 1H),
7.58－7.43 (m, 2H), 7.06 (d, J＝11.6 Hz, 1H), 6.55 (d,
J＝11.6 Hz, 1H), 4.25 (q, J＝7.1 Hz, 2H), 1.30 (t, J＝
7.1 Hz, 3H); 13C NMR (101 MHz, CDCl3) δ: 163.08,
140.25, 136.87, 135.16, 134.91, 132.73, 131.57, 127.89,
120.79, 62.12, 14.01; IR (neat) v: 2994, 1984, 1796,
1600, 1548, 1348, 1052 cm1; HRMS calcd for
C11H11BrO4S (M＋Na＋): 340.9459, found 340.9457.
(Z)-Ethyl
3-(mesitylsulfonyl)acrylate
(3ka)
White solid; yield 99% (69.8 mg); m.p. 67 ℃ (Lit. m.p.
66－68 ℃); H NMR (400 MHz, CDCl3) δ: 6.96 (s,
(Z)-2-Hydroxyethyl 3-tosylacrylate (3ae) Color-
less oil; yield 78% (52.7 mg); H NMR (400 MHz,
1
1
2H), 6.65 (d, J＝11.7 Hz, 1H), 6.41 (d, J＝11.7 Hz, 1H),
4.21 (q, J＝7.2 Hz, 2H), 2.64 (s, 6H), 2.30 (s, 3H), 1.29
(t, J＝7.2 Hz, 3H); 13C NMR (101 MHz, CDCl3) δ:
163.50, 143.68, 140.21, 138.15, 133.60, 132.10, 129.45,
61.94, 22.60, 21.03, 13.88; IR (neat) v: 2996, 1986,
1793, 1605, 1547, 1348, 1052 cm1; HRMS calcd for
C14H18O4S (M＋Na＋): 305.0823, found 305.0825.
CDCl3) δ: 7.85 (d, J＝8.1 Hz, 2H), 7.37 (d, J＝8.0 Hz,
2H), 6.51 (ABq, ΔδAB＝0.04, JAB＝12.0 Hz, 2H), 4.46
(t, J＝4.0 Hz, 2H), 3.94 (t, J＝4.3 Hz, 2H), 2.86 (s, 1H),
2.45 (s, 3H); 13C NMR (101 MHz, CDCl3) δ: 164.16,
145.60, 136.03, 135.39, 130.83, 130.18, 128.18, 68.09,
60.69, 21.72; IR (neat) v: 3362, 2991, 1985, 1794, 1603,
1548, 1348, 1052 cm1; HRMS calcd for C12H14O5S
(M＋Na＋): 293.0460, found 293.0456.
(Z)-Ethyl 3-(naphthalen-2-ylsulfonyl)acrylate (3la)
Yellow solid; yield 81% (58.7 mg); m.p. 77 ℃ (Lit.
(Z)-2-(Benzyloxy)ethyl
3-tosylacrylate
(3af)
1
m.p. 76－78 ℃); H NMR (400 MHz, CDCl3) δ: 8.57
White solid; yield 88% (79.2 mg); m.p. 100 ℃ (Lit.
m.p. 99－101 ℃); 1H NMR (400 MHz, CDCl3) δ: 7.88
(d, J＝7.9 Hz, 2H), 7.37－7.26 (m, 7H), 6.50 (ABq,
ΔδAB＝0.03, JAB＝12.0 Hz, 2H), 4.60 (s, 2H), 4.52－
4.45 (m, 2H), 3.81 (dd, J＝5.5, 3.9 Hz, 2H), 2.41 (s,
3H); 13C NMR (101 MHz, CDCl3) δ: 163.05, 144.17,
136.80, 135.29, 134.51, 130.03, 128.95, 127.41, 127.36,
126.83, 126.74, 72.22, 66.67, 64.05, 20.66; IR (neat) v:
2994, 1985, 1792, 1604, 1547, 1348, 1051 cm1; HRMS
calcd for C19H20O5S (M ＋ Na ＋ ): 383.0929, found
383.0927.
(d, J＝1.7 Hz, 1H), 8.05－7.90 (m, 4H), 7.66 (dt, J＝
21.1, 7.1 Hz, 2H), 6.56 (ABq, ΔδAB＝0.06, JAB＝10.0
Hz, 2H), 4.39 (q, J＝7.2 Hz, 2H), 1.41 (t, J＝7.1 Hz,
3H); 13C NMR (101 MHz, CDCl3) δ: 164.01, 136.29,
135.52, 135.17, 132.21, 131.89, 130.23, 129.68, 129.55,
129.50, 128.00, 127.71, 122.73, 62.24, 14.02. The data
meet the literature report.[6]
(Z)-Ethyl 3-(thiophen-2-ylsulfonyl)acrylate (3ma)
White solid; yield 100% (61.5 mg); m.p. 56 ℃ (Lit.
1
m.p. 55－57 ℃); H NMR (400 MHz, CDCl3) δ: 7.81
(d, J＝4.0 Hz, 1H), 7.75 (d, J＝4.0 Hz, 1H), 7.16 (t, J＝
4.0 Hz, 1H), 6.63 (d, J＝11.5 Hz, 1H), 6.48 (d, J＝11.3
Hz, 1H), 4.36 (q, J＝7.1 Hz, 2H), 1.38 (t, J＝7.1 Hz,
3H); 13C NMR (101 MHz, CDCl3) δ: 163.81, 140.70,
135.87, 135.21, 135.14, 131.59, 128.30, 62.35, 14.11.
The data meet the literature report.[6]
(Z)-2-Bromoethyl 3-tosylacrylate (3ag) White
solid; yield 92% (76.4 mg); m.p. 85 ℃ (Lit. m.p. 84－
86 ℃); H NMR (400 MHz, CDCl3) δ: 7.84 (d, J＝8.3
1
Hz, 2H), 7.34 (d, J＝8.0 Hz, 2H), 6.49 (ABq, ΔδAB
＝
0.04, JAB＝12.0 Hz, 2H), 4.58 (t, J＝6.3 Hz, 2H), 3.60
(t, J＝6.3 Hz, 2H), 2.42 (s, 3H); 13C NMR (101 MHz,
CDCl3) δ: 163.66, 145.41, 136.16, 135.93, 130.39,
(Z)-Methyl 3-tosylacrylate (3ab) Colorless oil;
Chin. J. Chem. 2016, 34, 1245—1250
© 2016 SIOC, CAS, Shanghai, & WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
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1247

Jiang et al.
Table 1 Optimization of the reaction conditionsa
FULL PAPER
130.06, 128.32, 65.07, 27.85, 21.71; IR (neat) v: 2992,
1984, 1793, 1602, 1548, 1348, 1051 cm1; HRMS calcd
for C12H13BrO4S (M＋Na＋): 354.9616, found 354.9617.
(Z)-2-Methoxy-2-oxoethyl 3-tosylacrylate (3ah)
Colorless oil; yield 85% (63.3 mg); 1H NMR (400 MHz,
CDCl3) δ: 7.89 (d, J＝8.0 Hz, 2H), 7.38 (d, J＝8.0 Hz,
2H), 6.58 (ABq, ΔδAB＝0.04, JAB＝12.0 Hz, 2H), 4.85
(s, 2H), 3.82 (s, 3H), 2.46 (s, 3H); 13C NMR (101 MHz,
CDCl3) δ: 166.52, 162.29, 144.41, 135.70, 129.04,
128.99, 127.41, 60.62, 51.41, 20.71; IR (neat) v: 2991,
1984, 1794, 1742, 1602, 1548, 1347, 1051 cm1; HRMS
calcd for C13H14O6S (M ＋ Na ＋ ): 298.0511, found
298.0509.
Entry Equiv. of 2a Temp./℃
Time Yieldb/% Z/Eb
1
2
2
2
2
2
1
3
4
3
3
3
3
3
3
3
r.t.
40
60
80
60
60
60
60
60
60
60
60
60
60
12 h
12 h
11
35
69
68
36
94
94
94
94
87
96
96
96
75
6∶1
6∶1
3
12 h
8∶1
4
12 h
8∶1
5
12 h
7∶1
6
12 h
13∶1
13∶1
13∶1
13∶1
13∶1
14∶1
14∶1
14∶1
14∶1
Deuterium generation (Z)-ethyl 3-tosylacrylate (4)
White solid; yield 96% (61.2 mg); m.p. 37 ℃ (Lit. m.p.
7
12 h
1
36－38 ℃); H NMR (400 MHz, CDCl3) δ: 7.88 (d,
8
2 h
J＝7.9 Hz, 2H), 7.36 (d, J＝7.9 Hz, 2H), 6.51 (s, 1H),
4.36 (q, J＝7.1 Hz, 2H), 2.45 (s, 3H), 1.39 (t, J＝7.1 Hz,
3H); 13C NMR (101 MHz, CDCl3) δ: 163.02, 144.18,
135.46, 134.37, 128.94, 127.28, 61.14, 20.69, 12.97; IR
(neat) v: 2994, 1985, 1794, 1602, 1548, 1348, 1051
cm1; HRMS calcd for C12H13DO4S (M ＋ Na ＋ ):
278.0573, found 278.0574.
9
1 h
10
11c
12d
13e
14f
30 min
30 min
15 min
10 min
5 min
Results and Discussion
a All reactions were performed with 4-methylbenzenesulfinate (1a,
1
0.25 mmol), water (2 mL), under air. b Estimated by H NMR
Firstly, the reaction of sodium 4-methylbenzenesul-
finate (1a) and ethyl propiolate (2a) under air atmos-
phere in water at room temprature for 12 h (Table 1,
Entry 1), gave the desired product (Z)-ethyl
3-tosylacrylate (3aa) in 11% NMR yield. Subsequently,
the temperature was tested and 60 ℃ was the best
choice (Entries 1 － 4). Then, control experiments
showed that the quantity of 2a had a strong influence on
the reaction and 3 equivalent of 2a could improve the
yield to 94% (Entries 4－7). We also studied the influ-
ence of reaction time, and 1 h had the same yield as 12 h
(Entry 6 vs. 8－10). More importantly, when we add 0.1
equivalent of H2SO4 to the reaction mixture, the reac-
tion time could be greatly reduced up to 10 min (Entry
10 vs. 11－14) and the yield was higher. We were
pleased to find that all of the conditions that we tested
resulted in the formation of Z-β-sulfonyl enoates in high
stereoselectivity. Thus, the best conditions for this pro-
cess comprised ratio (1a∶2a＝1∶3) under air atmos-
phere in water (2 mL) and 0.1 equivalent of H2SO4 at
60 ℃ for 10 min.
We then explored the scope of the reaction (Table 2).
First, we tested the scope of aromatic sodium sulfinates
and all the corresponding products were obtained in
excellent yields. The electronic effect of substituents at
the para position of the aryl sodium sulfinates was
evaluated (3aa－3fa). The reaction tolerated both elec-
tron-donating and electron-withdrawing groups. Aro-
matic sodium sulfinate with substituents at meta (3ga－
3ha) and ortho (3ia－3ja) positions also worked well,
although giving slightly lower yields. 2,4,6-Trimethyl-
benzene sodium sulfinate can also be used as reaction
spectroscopy using methylene bromide as an internal reference.
c,d, e 0.1 equivalent of H2SO4 and less time.
substrate, affording the desired product 3ka in good
yield. It is notable that the naphthalene substrate 1l and
the thiophene substrate 1m can also be transformed into
desired products 3la－3na in high yields.
To further exploit the generality of this catalytic re-
action, the propargyl esters were also investigated. Pro-
pargyl esters generally led to the corresponding products
in good yield. Many synthetically important functional
groups were readily tolerated, including an alkyl (3ab),
a phenyl (3ac), a benzyl (3ac), a free hydroxyl moiety
(3ae), a protected OH (3af), a bromide (3ag) and an
ester (3ah). To our delight, all of the examples in these
experiments had excellent stereoselectivity of Z config-
uration (Table 2).
To gain insight into the reaction mechanism, we
conducted a series of experiments (Scheme 2). First,
when the radical inhibitor TEMPO (2 equiv.) was em-
ployed under standard conditions, the reaction afforded
3aa in 90% yield (Scheme 3a), which implied that the
transformation did not proceed via a free-radical path-
way.[11] Then, with D2O (2 mL) as the solvent, the
transformation gave a deuterium generation product 4 in
96% yield (Scheme 3b). The deuterium generation ex-
periment implied that the α-hydrogen atom of
(Z)-β-sulfonyl enoates resulted from water. Furthermore,
the reaction yield of 3aa reduced to 18% at the basic
condition of 1 equiv. of NaOH (Scheme 3c). The alka-
line tests indicated that hydronium ions played an im-
portant role in the reaction.
1248
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© 2016 SIOC, CAS, Shanghai, & WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Chin. J. Chem. 2016, 34, 1245—1250

A Mild and Rapid Synthesis of (Z)-β-Sulfonyl Enoates from Sodium Sulfinates and Propargyl Esters
Table 2 Reaction scopea,b
vious reports,[12] a plausible mechanism is proposed in
Scheme 3. Firstly, sodium sulfinate is quickly turned
into a sulfinyl anion 5, which can resonate with the sul-
fur-centered anions 6 in the presence of water. Then, the
sulfur-centered anions 6 is selectively added into the
propargyl esters 2a leading to the intermediate 7 in the
presence of proton, which can turned into the carbon-
centered anions 8. Finally, the intermediate 8 affords
(Z)-β-sulfonyl enoate 3aa by a following proton transfer
(PT) from hydrion.
R
Scheme 3 The proposed mechanism for the reaction
O
S
CO2Et
O
O
O
H2O
R1
S
R1
S
R1SO2Na
p-Me 3aa, 96%,14/1
H 3ba, 93%,13/1
R =
O
5
O
6
1
p-OMe 3ca, 98%,16/1
p-F 3da, 94%,19/1
p-Cl 3ea, 93%,17/1
p-Br 3fa, 95%,14/1
m-Me 3ga, 97%,18/1
m-Br 3ha, 94%,15/1
o-Me 3ia, 95%,16/1
o-Br 3ja, 91%,13/1
O
O
R2
O
R1
S
H3O+
R1
R2
O
O
2
O
O
3
S
CO2Et
O
H2O
O
O
S
3la, 81%,15/1
H+
H3O+
O
O
S
O
S
R2
R1
O
O
-
O
EtO2C
S
OR2
O
8
7
3ma, 100%,12/1
Conclusions
CO2Ph
Ts
In summary, a simple and rapid regioselective sul-
fonylation of propargyl esters in water has been devel-
oped, giving (Z)-β-sulfonyl enoates in good yields. The
reaction proceeded under mild conditions without any
catalyst or organic solvent. A broad range of sodium
sulfinates and propargyl esters were tolerated in the re-
action, and all the sulfonylation products could be ob-
tained in good yields.
3ac, 76%,10/1
O
C
Ts
O
CO2Me
3ah, 85%,12/1
Acknowledgement
a Conditions: 1 (0.25 mmol) and 2 (0.75 mmol) in 2 mL of H2O,
0.1 equiv. of H2SO4, 60 ℃, under air, 10 min. b The yields re-
ported for a mixture of isomers after column chromatography.
This work was supported by the Planned Science
and Technology Project of Hunan Province, China (No.
2015WK3003).
Scheme 2 Control experiments
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On the basis of the results described above and pre-
Chin. J. Chem. 2016, 34, 1245—1250
© 2016 SIOC, CAS, Shanghai, & WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
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© 2016 SIOC, CAS, Shanghai, & WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Chin. J. Chem. 2016, 34, 1245—1250