Synthesis of sultams by ring-closing metathesis

Article abstract of DOI:10.1055/s-0033-1340360

Synthesis of a series of five-membered sultams containing different hetero- or carbocycles were obtained in good to excellent yields by ring-closing metathesis (RCM) reaction. Many sultams were precipitated from the reaction mixture and they were easily separated by filtration without further purification. Georg Thieme Verlag KG Stuttgart · New York.

Full text of DOI:10.1055/s-0033-1340360

368▌
PAPER
paper
Synthesis of Sultams by Ring-Closing Metathesis
Sultams by Ring-Closing Metathesis
Shovan Mondal,* Sudarshan Debnath
Department of Chemistry, Visva-Bharati (A Central University), Santiniketan 731235, India
Fax +91(3463)262728; E-mail: shovanku@gmail.com; E-mail: shovan.mondal@visva-bharati.ac.in
Received: 03.10.2013; Accepted after revision: 16.11.2013
In the literature, a number of classical cyclization proto-
cols such as Friedel–Craft,11 dianion,12 [3+2] cycloaddi-
tions,13 Diels–Alder reactions,14 etc., are reported to have
been used for the synthesis of sultams. However, recently,
transition-metal-catalyzed reactions like palladium-,15
gold-,16 copper-,17 and rhodium-catalyzed18 cyclization
been developed for the synthesis of sultam frameworks.
Ring-closing metathesis (RCM) is a very well-known
method for the construction of small- to large-ring sized
carbo- and heterocycles. A few sultams have also been
synthesized by ring-closing metathesis. For example, an
application of RCM in the synthesis of enantiopure sul-
tams was reported19 by Hanessian and co-workers in
2003. Subsequently, the synthesis of β-lactam-fused sul-
tams using an RCM reaction was developed by Metz and
co-workers in 2004.20 The synthesis of a sultam with a py-
ramidal nitrogen at the bridgehead and a sulfur atom at the
apex position was reported by Paquette and co-workers by
RCM methodology.21 A cascade ring-closure metathe-
sis/isomerization followed by radical cyclization was uti-
lized to synthesize sultams by Piva and co-workers.22 The
development of a ring-opening metathesis/ring-closing
metathesis/cross-metathesis (ROM–RCM–CM) cascade
strategy for the synthesis of diverse sultams was reported
by Hanson and co-workers.23 In our continued effort in
sultam chemistry,4a,24,25 we have now investigated the
synthesis of carbo- or heterocycle-containing sultams us-
ing the RCM reaction. Here we report our results.
Abstract: Synthesis of a series of five-membered sultams contain-
ing different hetero- or carbocycles were obtained in good to excel-
lent yields by ring-closing metathesis (RCM) reaction. Many
sultams were precipitated from the reaction mixture and they were
easily separated by filtration without further purification.
Keywords: sulfonamides, sultams, sulfonylation, ring-closing me-
tathesis, Grubbs II catalyst
Sulfonamide-containing compounds are rarely found in
nature, but they are extremely familiar because of their
chemical and biological utility.1–3 Recently, there has
been great interest directed towards sultams, the cyclic
counterpart of sulfonamides, as pharmaceuticals and agri-
cultural agents.4,5 Three biologically active sultams are
shown in Figure 1.
O
O
O
O
S
t-Bu
S
N
Me
N
Et
H
HO
OH
t-Bu
I
II
anti-HIV-1 agent
S-2474
COX-2 inhibitor
SO2NH2
O
O
S
N
For the synthesis of sultams, the monoallylamine com-
pounds 1a–k (Table 1), which are common starting mate-
rials, were prepared according to standard literature
procedures.26 For example, compound 1a was prepared by
the tosylation of allylamine whereas compounds 1b–e,g,h
were prepared by tosylation of the corresponding amines
followed by reaction with allyl bromide and finally depro-
tection of the tosyl group. Sometimes in the treatment of
allyl bromide with the free amine, the monoallyl product
appears as the major compound. We chose this method for
the synthesis of monoallylamine derivatives as in the case
of 1f and 1i. Compounds 1j and 1k were synthesized by
the treatment of allylamine with 5-bromouracil deriva-
tives.
III
sulthiame
anticonvulsant
Figure 1 Selected biologically active sultams
The sultam S-24746 (I) is used as a COX-2 inhibitor
whereas the compound II7 acts as an anti-HIV agent. Sul-
thiame (III) is popular as a carbonic anhydrase inhibitor
and used as an anticonvulsant.8 In addition to their appli-
cation as pharmaceuticals, sultams are also used as key in-
termediates for the total synthesis of many natural
products. For example, Ley and co-workers reported9 the
total synthesis of epothilone C (a potent cytotoxic antitu-
mor agent) via a sultam intermediate. Holmes and co-
workers developed10 the total synthesis of (–)-histrionico-
toxin, (+)-histrionicotoxin, and (–)-histrionicotoxin 235A
employing sultams.
To a solution of the monoallylamines 1a–k in dichloro-
methane, triethylamine was added and the mixture was
stirred for 15 minutes at room temperature. Then 2-chlo-
roethanesulfonyl chloride was added dropwise to the reac-
tion mixture at 0 °C and the mixture was stirred for one
hour at this temperature to give the ethenesulfonamides
SYNTHESIS 2014, 46, 0368–0374
Advanced online publication: 03.12.2013
0
0
3
9
-
7
8
8
1
1
4
3
7
-
2
1
0
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DOI: 10.1055/s-0033-1340360; Art ID: SS-2013-Z0657-OP
© Georg Thieme Verlag Stuttgart · New York

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Sultams by Ring-Closing Metathesis
369
2a–k in excellent yields, which are the precursors in this
study of the synthesis of five-membered sultams (Table 1).
3a
Table 1 Synthesis of Ethenesulfonamides
Cl
Cl
Grubbs II (5 mol%)
toluene, 80 °C, 1 h
S
O2
2a
O
O
Et3N, CH2Cl2, 0 °C, 1 h
96%
S
N
R
NH
R
no further purification
required
1a–k
2a–k
Scheme 1 Synthesis of sultam 3a
Entry Substrate
R
Sulfonamide Yield (%)
After this satisfactory result, sultam precursors 2b–k were
reacted under the same reaction conditions, i.e., 5 mol%
Grubbs II catalyst in toluene at 80 °C for one hour, and
they gave the sultams 3b–k in 60–95% yields (Table 2).
Sultams 3b–e precipitated from the reaction mixture as in
the case of sultam 3a and they were isolated by simple fil-
1
2
1a
1b
Ts
2a
2b
85
80
4-O2NC6H4
3
1c
2c
86
O
O
Table 2 RCM Reaction To Give Sultams
4
5
1d
1e
2d
2e
90
92
O
O
Grubbs II (5 mol%)
toluene, 80 °C, 1 h
O
O
O
O
S
S
N
R
N
R
N
O
2a–k
3a–k
Me
6
7
8
9
1f
3-MeOC6H4
Ph
2f
88
85
83
85
Entry
R
Sultam
Yield (%)
1g
1h
1i
2g
2h
2i
1
2
Ts
3a
3b
96
90
4-MeC6H4
4-O2NC6H4
2-pyridyl
O
3
3c
92
MeN
O
O
10
11
1j
2j
95
92
O
N
Me
4
5
3d
3e
95
95
O
O
O
EtN
1k
2k
O
N
Et
N
O
Me
6
7
8
9
3-MeOC6H4
Ph
3f
93
90
88
60
To reach the final goal, i.e. the synthesis of sultams by
RCM, the RCM of N-allyl-N-tosylethenesulfonamide
(2a) was examine. Initially, compound 2a was treated
with Grubbs I catalyst in dichloromethane at room tem-
perature, but no conversion was shown by TLC. The same
reaction was then performed under reflux for 24 hours and
it also showed no reaction by TLC. Next the use of Grubbs
II catalyst was examined. When compound 2a was react-
ed in with 5 mol% Grubbs II catalyst in toluene at 80 °C
for 1 h, interestingly, the cyclized product 3a precipitated
out of the reaction mixture. The precipitate was filtered
off to give 3a in 96% yield (100% conversion) as a white
solid (Scheme 1). No further purification was needed.
3g
3h
3i
4-MeC6H4
2-pyridyl
O
MeN
10
11
3j
92
91
O
N
Me
O
EtN
3k
O
N
Et
© Georg Thieme Verlag Stuttgart · New York
Synthesis 2014, 46, 368–374

370
S. Mondal, S. Debnath
PAPER
CH2CH=CHaHb), 5.23–5.18 (m, 2 H, CH2CH=CHaHb), 4.33–4.31
(m, 2 H, CH2CH=CHaHb).
13C NMR (100 MHz, CDCl3): δ = 146.2, 145.2, 134.1, 132.1, 129.0,
127.6, 124.6, 120.0, 53.2.
MS (ESI): m/z = 269 [M + H]+.
tration, whereas sultams 3f–k were purified by column
chromatography through a small bed of silica gel. The
comparatively low yield of 3i can be explained by the co-
ordination of the pyridine nitrogen, which might interrupt
the catalytic system of the metathesis reaction.
Anal. Calcd for C11H12N2O4S: C, 49.24; H, 4.51; N, 10.44. Found:
C, 49.33; H, 4.56; N, 10.32.
In conclusion, we have successfully demonstrated the
synthesis of a series of five-membered sultams containing
different hetero- or carbocycles via ring-closing metathe-
N-Allyl-N-(4-methyl-2-oxo-2H-1-benzopyran-7-yl)ethenesul-
sis (RCM) reaction in 60–96% yields. Our next endeavor fonamide (2c)
Following the typical procedure for 2a using 1c (300 mg, 1.39
is to study the biological activity of the newly synthesized
sultams and this will be reported in due course.
mmol), Et3N (0.74 mL, 5.57 mmol), and 2-chloroethanesulfonyl
chloride (0.22 mL, 2.10 mmol) in anhyd CH2Cl2 (10 mL). The crude
product was purified by column chromatography (silica gel, 70%
EtOAc–PE) to afford 2c (367 mg, 86%) as a colorless liquid; Rf =
0.55 (80% EtOAc–PE).
Column chromatography was performed on silica gel, Merck grade
60–120 mesh. Petroleum ether = PE. Reactions were monitored by
TLC (visualized: UV and iodine chamber). TLC was not performed
on 3a–e due to solubility problems. Melting points were recorded in
open capillaries and are uncorrected. IR spectra were recorded on a
Shimadzu FT-IR 8400S spectrophotometer using KBr discs. 1H and
13C NMR spectra were recorded on a Bruker Ascend spectrometer
(400 MHz and 100 MHz, for 1H and 13C, respectively) relative to the
solvent [1H: δ = 7.26 (CHCl3) and δ = 2.50 (DMSO-d5); 13C:
δ = 77.16 (CDCl3) and δ = 39.52 (DMSO-d6)]. Mass spectra were
recorded on a Finnigan MAT 1020 mass spectrometer operating at
70 eV. CHN analyses were recorded on a 2400 series II CHN ana-
lyzer (Perkin-Elmer). All reactions were performed under a N2 at-
mosphere using freshly dried solvents unless noted.
IR (KBr): 2341, 1604, 1338, 1149 cm–1.
1H NMR (400 MHz, CDCl3): δ = 7.61 (d, J = 8.5 Hz, 1 H, HAr),
7.34–7.26 (m, 2 H, HAr), 6.57 (dd, J = 16.5, 9.9Hz, 1 H, CHSO2),
6.32 (s, 1 H, COCH), 6.26 (d, J = 16.5 Hz, 1 H, HaHbC=CHSO2),
6.06 (d, J = 9.9 Hz, 1 H, HaHbC=CHSO2), 5.87–5.80 (m, 1 H,
CH2CH=CHaHb), 5.22 (d, J = 16.7 Hz, 1 H, CH2CH=CHaHb), 5.19
(d, J = 9.9 Hz, 1 H, CH2CH=CHaHb), 4.30 (d, J = 6.0 Hz, 2 H,
CH2CH=CHaHb), 2.45 (s, 3 H, CH3).
13C NMR (100 MHz, CDCl3): δ = 160.4, 153.7, 151.9, 142.3, 134.1,
132.2, 128.6, 125.2, 124.1, 119.7, 119.1, 115.4, 115.2, 53.3, 18.7.
MS (ESI): m/z = 306 [M + H]+.
Anal. Calcd for C15H15NO4S: C, 59.00; H, 4.95; N, 4.59. Found: C,
59.17; H, 4.99; N, 4.51.
N-Allyl-N-tosylethenesulfonamide (2a); Typical Procedure
To a solution of 1a (250 mg, 1.18 mmol) in anhyd CH2Cl2 (10 mL),
Et3N (0.63 mL, 4.73 mmol) was added under a N2 atmosphere and
the mixture was stirred for 15 min at r.t. Then 2-chloroethanesulfo-
nyl chloride (0.2 mL, 1.77 mmol) was added dropwise to the mix-
ture at 0 °C and it was stirred for a further 1 h at the same
temperature. The residual solvent was evaporated under reduced
pressure and the crude product obtained was purified by column
chromatography (silica gel, 20% EtOAc–PE) to afford 2a (305 mg,
85%) as a colorless liquid; Rf = 0.55 (20% EtOAc–PE).
N-Allyl-N-(2-oxo-2H-1-benzopyran-6-yl)ethenesulfonamide
(2d)
Following the typical procedure for 2a using 1d (350 mg, 1.74
mmol), Et3N (0.93 mL, 6.96 mmol), and 2-chloroethanesulfonyl
chloride (0.27 mL, 2.61 mmol) in anhyd CH2Cl2 (10 mL). The crude
product was purified by column chromatography (silica gel, 30%
EtOAc–PE) to afford 2d (455 mg, 90%) as a colorless liquid; Rf =
0.30 (30% EtOAc–PE).
IR (KBr): 1620, 1365, 1164 cm–1.
IR (KBr): 2353, 1737, 1342, 1163 cm–1.
1H NMR (400 MHz, CDCl3): δ = 7.87 (d, J = 8.4 Hz, 2 H, HAr), 7.31
(d, J = 8.2 Hz, 2 H, HAr), 6.92 (dd, J = 16.6, 9.9 Hz, 1 H, CHSO2),
6.35 (d, J = 16.6 Hz, 1 H, HaHbC=CHSO2), 6.07 (d, J = 9.5 Hz, 1 H,
HaHbC=CHSO2), 5.87–5.78 (m, 1 H, CH2CH=CHaHb), 5.28 (dd,
J = 17.1, 1.1 Hz, 1 H, CH2CH=CHaHb), 5.20 (dd, J = 10.2, 0.9 Hz,
1 H, CH2CH=CHaHb), 4.27–4.25 (m, 2 H, CH2CH=CHaHb), 2.43 (s,
3 H, CH3).
13C NMR (100 MHz, CDCl3): δ = 145.2, 137.3, 136.8, 132.5, 129.8,
128.6, 128.4, 120.1, 51.3, 21.8.
MS (ESI): m/z = 302 [M + H]+.
1H NMR (400 MHz, CDCl3): δ = 7.67 (d, J = 9.6 Hz, 1 H,
COCH=CH), 7.44 (d, J = 2.4 Hz, 1 H, HAr), 7.39 (dd, J = 8.8, 2.5
Hz, 1 H, HAr), 7.28 (d, J = 8.8 Hz, 1 H, HAr), 6.54 (dd, J = 16.5, 9.9
Hz, 1 H, CHSO2), 6.43 (d, J = 9.6 Hz, 1 H, COCH=CH), 6.16
(d, J = 16.5 Hz, 1 H, HaHbC=CHSO2), 5.99 (d, J = 9.8 Hz, 1 H,
HaHbC=CHSO2), 5.82–5.72 (m, 1 H, CH2CH=CHaHb), 5.14–5.10
(m,
2 H, CH2CH=CHaHb), 4.19 (d, J = 6.4 Hz, 2 H,
CH2CH=CHaHb).
13C NMR (100 MHz, CDCl3): δ = 160.2, 153.2, 143.0, 135.1, 134.0,
132.4, 131.8, 128.7, 128.5, 119.8, 119.3, 117.8, 117.5, 53.9.
MS (ESI): m/z = 292 [M + H]+.
Anal. Calcd for C12H15NO4S2: C, 47.82; H, 5.02; N, 4.65. Found: C,
47.67; H, 5.14; N, 4.69.
Anal. Calcd for C14H13NO4S: C, 57.72; H, 4.50; N, 4.81. Found: C,
57.59; H, 4.61; N, 4.88.
N-Allyl-N-(4-nitrophenyl)ethenesulfonamide (2b)
Following the typical procedure for 2a using 1b (250 mg, 1.40
mmol), Et3N (0.75 mL, 5.61 mmol), and 2-chloroethanesulfonyl
chloride (0.22 mL, 2.10 mmol) in anhyd CH2Cl2 (10 mL). The crude
product was purified by column chromatography (silica gel, 20%
EtOAc–PE) to afford 2b (300 mg, 80%) as a yellowish liquid; Rf =
0.40 (20% EtOAc–PE).
N-Allyl-N-(1-methyl-2-oxo-1,2-dihydroquinolin-6-yl)ethenesul-
fonamide (2e)
Following the typical procedure for 2a using 1e (300 mg, 1.40
mmol), Et3N (0.75 mL, 5.60 mmol), and 2-chloroethanesulfonyl
chloride (0.22 mL, 2.10 mmol) in anhyd CH2Cl2 (10 mL). The crude
product was purified by column chromatography (silica gel, 70%
EtOAc–PE) to afford 2e (395 mg, 92%) as a light yellowish liquid;
Rf = 0.50 (70% EtOAc–PE).
IR (KBr): 1599, 1514, 1344, 1153 cm–1.
1H NMR (400 MHz, CDCl3): δ = 8.21 (dt, J = 9.0, 1.9 Hz, 2 H, HAr),
7.47 (dt, J = 9.0, 2.0 Hz, 2 H, HAr), 6.53 (dd, J = 16.5, 9.9 Hz, 1 H,
CHSO2), 6.25 (d, J = 16.5 Hz, 1 H, HaHbC=CHSO2), 6.05 (d,
IR (KBr): 2339, 1741, 1654, 1344 cm–1.
1H NMR (400 MHz, CDCl3): δ = 7.62 (d, J = 9.5 Hz, 1 H,
COCH=CH), 7.47–7.45 (m, 2 H, HAr), 7.33 (d, J = 9.8 Hz, 1 H,
J = 9.8 Hz,
1 H, HaHbC=CHSO2), 5.85–5.75 (m, 1 H,
Synthesis 2014, 46, 368–374
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Sultams by Ring-Closing Metathesis
371
HAr), 6.72 (d, J = 9.5 Hz, 1 H, COCH=CH), 6.55 (dd, J = 16.5, 9.8
Hz, 1 H, CHSO2), 6.17 (d, J = 16.6 Hz, 1 H, HaHbC=CHSO2), 5.99
(d, J = 9.9 Hz, 1 H, HaHbC=CHSO2), 5.86–5.76 (m, 1 H,
CH2CH=CHaHb), 5.16–5.11 (m, 2 H, CH2CH=CHaHb), 4.22 (d,
J = 6.4 Hz, 2 H, CH2CH=CHaHb), 3.69 (s, 3 H, NCH3).
13C NMR (100 MHz, CDCl3): δ = 138.1, 136.4, 134.4, 133.0, 129.9,
128.7, 127.4, 118.9, 53.9, 21.1.
MS (ESI): m/z = 238 [M + H]+.
Anal. Calcd for C12H15NO2S: C, 60.73; H, 6.37; N, 5.90. Found: C,
60.82; H, 6.29; N, 5.79.
13C NMR (100 MHz, CDCl3): δ = 162.3, 139.6, 138.6, 134.3, 133.1,
132.7, 131.1, 128.9, 128.2, 122.8, 121.1, 119.7, 115.2, 54.0, 29.7.
MS (ESI): m/z = 305 [M + H]+.
N-Allyl-N-(2-pyridyl)ethenesulfonamide (2i)
Following the typical procedure for 2a using 1i (250 mg, 1.86
mmol), Et3N (1 mL, 7.45 mmol), and 2-chloroethanesulfonyl chlo-
ride (0.30 mL, 2.79 mmol) in anhyd CH2Cl2 (10 mL). The crude
product was purified by column chromatography (silica gel, 20%
EtOAc–PE) to afford 2i (358 mg, 85%) as a yellowish liquid; Rf =
0.60 (20% EtOAc–PE).
Anal. Calcd for C15H16N2O3S: C, 59.19; H, 5.30; N, 9.20. Found: C,
59.01; H, 5.22; N, 9.29.
N-Allyl-N-(3-methoxyphenyl)ethenesulfonamide (2f)
Following the typical procedure for 2a using 1f (300 mg, 1.84
mmol), Et3N (1 mL, 7.35 mmol), and 2-chloroethanesulfonyl chlo-
ride (0.30 mL, 2.76 mmol) in anhyd CH2Cl2 (10 mL). The crude
product was purified by column chromatography (silica gel, 30%
EtOAc–PE) to afford 2f (410 mg, 88%) as a light greenish liquid;
Rf = 0.50 (30% EtOAc–PE).
IR (KBr): 2337, 1587, 1151 cm–1.
1H NMR (400 MHz, CDCl3): δ = 8.40–8.39 (m, 1 H, HAr), 7.68 (td,
J = 7.7, 2.0 Hz, 1 H, HAr), 7.39 (d, J = 8.1 Hz, 1 H, HAr), 7.15–7.12
(m, 1 H, HAr), 6.67 (dd, J = 16.6, 9.9 Hz, 1 H, CHSO2), 6.25 (d,
J = 16.6 Hz, 1 H, HaHbC=CHSO2), 5.96 (d, J = 9.9 Hz, 1 H, HaH-
bC=CHSO2), 5.90–5.80 (m, 1 H, CH2CH=CHaHb), 5.21 (dd,
J = 17.2, 1.4 Hz, 1 H, CH2CH=CHaHb), 5.10 (dd, J = 10.2, 1.3 Hz,
IR (KBr): 2354, 1735, 1598, 1340 cm–1.
1H NMR (400 MHz, CDCl3): δ = 7.29–7.25 (m, 1 H, HAr), 6.89–
6.85 (m, 3 H, HAr), 6.56 (dd, J = 16.6, 9.9 Hz, 1 H, CHSO2), 6.20 (d,
J = 16.6 Hz, 1 H, HaHbC=CHSO2), 5.98 (d, J = 9.9 Hz, 1 H, HaH-
bC=CHSO2), 5.88–5.78 (m, 1 H, CH2CH=CHaHb), 5.20–5.12 (m, 2
H, CH2CH=CHaHb), 4.20 (d, J = 6.3 Hz, 2 H, CH2CH=CHaHb),
3.81 (s, 3 H, OCH3).
13C NMR (100 MHz, CDCl3): δ = 160.1, 140.3, 134.4, 132.9, 129.8,
127.6, 120.7, 119.1, 115.0, 113.5, 55.5, 53.9.
MS (ESI): m/z = 254 [M + H]+.
1
H, CH2CH=CHaHb), 4.43 (dt, J = 5.9, 1.3 Hz,
2 H,
CH2CH=CHaHb).
13C NMR (100 MHz, CDCl3): δ = 152.6, 148.4, 138.1, 135.2, 133.1,
127.5, 121.7, 121.3, 118.5, 51.1.
MS (ESI): m/z = 225 [M + H]+.
Anal. Calcd for C10H12N2O2S: C, 53.55; H, 5.39; N, 12.49. Found:
C, 53.59; H, 5.44; N, 12.41.
N-Allyl-N-(1,3-dimethyl-2,4-dioxo-1,2,3,4-tetrahydropyrimi-
din-5-yl)ethenesulfonamide (2j)
Anal. Calcd for C12H15NO3S: C, 56.90; H, 5.97; N, 5.53. Found: C,
56.99; H, 5.91; N, 5.62.
Following the typical procedure for 2a using 1j (300 mg, 1.54
mmol), Et3N (0.82 mL, 6.15 mmol), and 2-chloroethanesulfonyl
chloride (0.24 mL, 2.30 mmol) in anhyd CH2Cl2 (10 mL). The crude
product was purified by column chromatography (silica gel, 50%
EtOAc–PE) to afford 2j (415 mg, 95%) as a white solid; mp 112–
115 °C; Rf = 0.60 (50% EtOAc–PE).
N-Allyl-N-phenylethenesulfonamide (2g)
Following the typical procedure for 2a using 1g (350 mg, 2.63
mmol), Et3N (1.40 mL, 10.51 mmol), and 2-chloroethanesulfonyl
chloride (0.42 mL, 3.94 mmol) in anhyd CH2Cl2 (10 mL). The crude
product was purified by column chromatography (silica gel, 10%
EtOAc–PE) to afford 2g (500 mg, 85%) as a colorless liquid; Rf =
0.45 (10% EtOAc–PE).
IR (KBr): 2333, 1668, 1157 cm–1.
1H NMR (400 MHz, CDCl3): δ = 7.41 (s, 1 H, CH), 6.62 (dd,
J = 16.5, 9.9 Hz, 1 H, CHSO2), 6.23 (d, J = 16.5 Hz, 1 H, HaH-
bC=CHSO2), 5.98 (d, J = 9.9 Hz, 1 H, HaHbC=CHSO2), 5.80–5.70
(m, 1 H, CH2CH=CHaHb), 5.16–5.11 (m, 2 H, CH2CH=CHaHb),
3.99 (d, J = 5.2 Hz, 2 H, CH2CH=CHaHb), 3.39 (s, 3 H, NCH3), 3.30
(s, 3 H, NCH3).
13C NMR (100 MHz, CDCl3): δ = 161.2, 151.0, 147.0, 135.3, 133.0,
127.6, 119.6, 111.8, 51.4, 37.6, 28.4.
MS (ESI): m/z = 286 [M + H]+.
IR (KBr): 2337, 1593, 1338 cm–1.
1H NMR (400 MHz, CDCl3): δ = 7.39–7.29 (m, 5 H, HAr), 6.56 (dd,
J = 16.5, 9.9 Hz, 1 H, CHSO2), 6.16 (d, J = 16.5 Hz, 1 H, HaH-
bC=CHSO2), 5.97 (d, J = 9.9 Hz, 1 H, HaHbC=CHSO2), 5.87–5.77
(m, 1 H, CH2CH=CHaHb), 5.18–5.11 (m, 2 H, CH2CH=CHaHb),
4.22 (d, J = 6.3 Hz, 2 H, CH2CH=CHaHb).
13C NMR (100 MHz, CDCl3): δ = 139.0, 134.3, 132.8, 129.2, 128.8,
128.0, 127.6, 119.0, 53.8.
MS (ESI): m/z = 224 [M + H]+.
Anal. Calcd for C11H15N3O4S: C, 46.31; H, 5.30; N, 14.73. Found:
C, 46.41; H, 5.37; N, 14.79.
Anal. Calcd for C11H13NO2S: C, 59.17; H, 5.87; N, 6.27. Found: C,
59.26; H, 5.94; N, 6.19.
N-Allyl-N-(1,3-diethyl-2,4-dioxo-1,2,3,4-tetrahydropyrimidin-
5-yl)ethenesulfonamide (2k)
N-Allyl-N-(4-methylphenyl)ethenesulfonamide (2h)
Following the typical procedure for 2a using 1h (350 mg, 2.38
mmol), Et3N (1.27 mL, 9.51 mmol), and 2-chloroethanesulfonyl
chloride (0.38 mL, 3.57 mmol) in anhyd CH2Cl2 (10 mL). The crude
product was purified by column chromatography (silica gel, 10%
EtOAc–PE) to afford 2h (470 mg, 83%) as a light orange liquid;
Rf = 0.30 (10% EtOAc–PE).
Following the typical procedure for 2a using 1k (300 mg, 1.34
mmol), Et3N (0.72 mL, 5.37 mmol), and 2-chloroethanesulfonyl
chloride (0.21 mL, 2.01 mmol) in anhyd CH2Cl2 (10 mL). The crude
product was purified by column chromatography (silica gel, 20%
EtOAc–PE) to afford 2k (389 mg, 92%) as a white solid; mp 92–
95 °C; Rf = 0.50 (20% EtOAc–PE).
IR (KBr): 2333, 1649, 1452, 1139 cm–1.
IR (KBr): 2354, 1915, 1514, 1338 cm–1.
1H NMR (400 MHz, CDCl3): δ = 7.37 (s, 1 H, CH), 6.64 (dd,
J = 16.5, 9.9 Hz, 1 H, CHSO2), 6.24 (d, J = 16.5 Hz, 1 H, HaH-
bC=CHSO2), 5.98 (d, J = 9.9 Hz, 1 H, HaHbC=CHSO2), 5.81–5.72
(m, 1 H, CH2CH=CHaHb), 5.17–5.12 (m, 2 H, CH2CH=CHaHb),
4.00 (d, J = 6.0 Hz, 2 H, CH2CH=CHaHb), 3.99–3.94 (q, J = 7.1 Hz,
2 H, CH2CH3), 3.83–3.78 (q, J = 7.3 Hz, 2 H, CH2CH3), 1.31 (t,
J = 7.1 Hz, 3 H, CH2CH3), 1.19 (t, J = 7.1 Hz, 3 H, CH2CH3).
1H NMR (400 MHz, CDCl3): δ = 7.18 (s, 4 H, HAr), 6.56 (dd,
J = 16.5, 9.9 Hz, 1 H, CHSO2), 6.16 (d, J = 16.5 Hz, 1 H, HaH-
bC=CHSO2), 5.96 (d, J = 10.0 Hz, 1 H, HaHbC=CHSO2), 5.86–5.77
(m, 1 H, CH2CH=CHaHb), 5.18–5.11 (m, 2 H, CH2CH=CHaHb),
4.19 (dt, J = 6.2, 1.1 Hz, 2 H, CH2CH=CHaHb), 2.35 (s, 3 H, CH3).
© Georg Thieme Verlag Stuttgart · New York
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S. Mondal, S. Debnath
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13C NMR (100 MHz, CDCl3): δ = 160.8, 150.2, 145.9, 135.4, 133.1,
127.4, 119.6, 112.1, 51.4, 45.4, 37.2, 14.3, 12.8.
(10 mL). The product was precipitated out and filtered off to afford
3d (86 mg, 95%) as a white solid; mp >250 °C.
MS (ESI): m/z = 314 [M + H]+.
IR (KBr): 3070, 2335, 1728, 1182 cm–1.
Anal. Calcd for C13H19N3O4S: C, 49.83; H, 6.11; N, 13.41. Found:
C, 49.77; H, 6.18; N, 13.36.
1H NMR (400 MHz, CDCl3): δ = 7.05 (d, J = 9.6 Hz, 1 H,
COCH=CH), 6.60–6.57 (m, 2 H, HAr), 6.46 (d, J = 8.8 Hz, 1 H,
HAr), 6.37 (s, 2 H, SO2CH, CH2CH), 5.50 (d, J = 9.5 Hz, 1 H,
COCH=CH), 3.62 (s, 2 H, CH2CH).
13C NMR (100 MHz, DMSO-d6): δ = 160.1, 149.9, 144.0, 136.5,
133.5, 126.7, 122.3, 119.5, 117.7, 117.3, 117.2, 51.1.
2-Tosyl-2,3-dihydroisothiazole 1,1-Dioxide (3a); Typical Proce-
dure
N2 gas was bubbled through a solution of 2a (100 mg, 0.33 mmol)
in distilled toluene (5 mL) for 10 min (substrate solution). A solu-
tion of Grubbs II catalyst (14 mg, 5 mol%) in distilled toluene (5
mL) was also degassed with N2 for 10 min (catalyst solution). Then
the catalyst solution was added dropwise to the substrate solution
and the mixture was heated for 1 h at 80 °C under N2. The product
was precipitated out and it was filtered off to afford 3a (87 mg,
96%) as a white solid; mp >250 °C.
MS (ESI): m/z = 264 [M + H]+.
Anal. Calcd for C12H9NO4S: C, 54.75; H, 3.45; N, 5.32. Found: C,
54.84; H, 3.51; N, 5.37.
2-(1-Methyl-2-oxo-1,2-dihydroquinolin-6-yl)-2,3-dihydroiso-
thiazole 1,1-Dioxide (3e)
Following the typical procedure for 3a using 2e (100 mg, 0.33
mmol), Grubbs II catalyst (14 mg, 5 mol%), and distilled toluene
(10 mL). The product was precipitated out and filtered off to afford
3e (87 mg, 95%) as a white solid; mp >250 °C.
IR (KBr): 3091, 2331, 1348, 1174 cm–1.
1H NMR (400 MHz, CDCl3): δ = 6.95 (d, J = 8.3 Hz, 2 H, HAr), 6.57
(d, J = 8.1 Hz, 2 H, HAr), 6.40 (dt, J = 7.1, 2.1 Hz, 1 H, SO2CH),
6.20 (dt, J = 7.1, 2.1 Hz, 1 H, CH2CH), 3.46 (t, J = 2.2 Hz, 2 H,
CH2CH), 2.47 (s, 3 H, CH3).
IR (KBr): 3074, 2337, 1652, 1280 cm–1.
1H NMR (400 MHz, DMSO-d6): δ = 6.96 (d, J = 9.5 Hz, 1 H,
COCH=CH), 6.74–6.65 (m, 3 H, HAr), 6.46 (s, 2 H, SO2CH,
CH2CH), 5.72 (d, J = 9.6 Hz, 1 H, COCH=CH), 3.71 (s, 2 H,
CH2CH), 2.68 (s, 3 H, NCH3).
13C NMR (100 MHz, DMSO-d6): δ = 145.6, 135.4, 133.4, 130.1,
128.1, 126.4, 50.6, 21.4.
MS (ESI): m/z = 296 [M + Na]+.
Anal. Calcd for C10H11NO4S2: C, 43.94; H, 4.06; N, 5.12. Found: C,
44.02; H, 3.99; N, 5.18.
13C NMR (100 MHz, DMSO-d6): δ = 160.9, 138.8, 136.4, 131.3,
126.8, 122.2, 122.1, 120.8, 117.9, 116.0, 51.1, 29.2.
2-(4-Nitrophenyl)-2,3-dihydroisothiazole 1,1-Dioxide (3b)
Following the typical procedure for 3a using 2b (100 mg, 0.37
mmol), Grubbs II catalyst (16 mg, 5 mol%), and distilled toluene
(10 mL). The product was precipitated out and filtered off to afford
3b (81 mg, 90%) as a white solid; mp >250 °C.
MS (ESI): m/z = 277 [M + H]+.
Anal. Calcd for C13H12N2O3S: C, 56.51; H, 4.38; N, 10.14. Found:
C, 56.62; H, 4.44; N, 10.07.
2-(3-Methoxyphenyl)-2,3-dihydroisothiazole 1,1-Dioxide (3f)
Following the typical procedure for 3a using 2f (100 mg, 0.39
mmol), Grubbs II catalyst (17 mg, 5 mol%), and distilled toluene
(10 mL). The crude product was purified by column chromatogra-
phy (silica gel, 50% EtOAc–PE) to afford 3f (83 mg, 93%) as a
white solid; mp 83–86 °C; Rf = 0.45 (50% EtOAc–PE).
IR (KBr): 3093, 2339, 1298, 1122 cm–1.
1H NMR (400 MHz, CDCl3): δ = 7.33 (d, J = 9.2 Hz, 2 H, HAr),
6.51–6.46 (m, 4 H, HAr, SO2CH, CH2CH), 3.76 (d, J = 2.0 Hz, 2 H,
CH2CH).
13C NMR (100 MHz, DMSO-d6): δ = 143.0, 141.8, 136.5, 126.5,
125.6, 115.7, 50.5.
IR (KBr): 3085, 2335, 1604, 1290 cm–1.
1H NMR (400 MHz, CDCl3): δ = 7.20 (t, J = 8.2 Hz, 1 H, HAr), 6.88
(d, J = 7.1 Hz, 1 H, HAr), 6.83–6.79 (m, 2 H, HAr), 6.66 (d, J = 7.0
Hz, 1 H, SO2CH), 6.60 (dd, J = 8.4, 1.9 Hz, 1 H, CH2CH), 4.34 (s,
2 H, CH2CH), 3.72 (s, 3 H, OCH3).
MS (ESI): m/z = 263 [M + Na]+.
Anal. Calcd for C9H8N2O4S: C, 45.00; H, 3.36; N, 11.66. Found: C,
45.12; H, 3.43; N, 11.59.
13C NMR (100 MHz, CDCl3): δ = 160.6, 137.8, 134.0, 130.5, 127.6,
110.5, 109.6, 104.6, 55.5, 50.8.
MS (ESI): m/z = 226 [M + H]+.
2-(4-Methyl-2-oxo-2H-1-benzopyran-7-yl)-2,3-dihydroisothia-
zole 1,1-Dioxide (3c)
Following the typical procedure for 3a using 2c (100 mg, 0.33
mmol), Grubbs II catalyst (14 mg, 5 mol%), and distilled toluene
(10 mL). The product was precipitated out and filtered off to afford
3c (84 mg, 92%) as a white solid; mp >250 °C.
Anal. Calcd for C10H11NO3S: C, 53.32; H, 4.92; N, 6.22. Found: C,
53.44; H, 4.88; N, 6.28.
IR (KBr): 3056, 2331, 1685, 1135 cm–1.
2-Phenyl-2,3-dihydroisothiazole 1,1-Dioxide (3g)
Following the typical procedure for 3a using 2g (100 mg, 0.45
mmol), Grubbs II catalyst (19 mg, 5 mol%), and distilled toluene
(10 mL). The crude product was purified by column chromatogra-
phy (silica gel, 50% EtOAc–PE) to afford 3g (78 mg, 90%) as a
white solid; mp 145–148 °C; Rf = 0.30 (30% EtOAc–PE).
1H NMR (400 MHz, CDCl3): δ = 6.95 (d, J = 8.8 Hz, 1 H, HAr),
6.60–6.56 (m, 2 H, HAr), 6.50 (dd, J = 8.7, 1.7 Hz, 1 H, SO2CH),
6.31 (d, J = 1.4 Hz, 1 H, COCH), 5.43 (s, 1 H, CH2CH), 3.85 (s, 2
H, CH2CH), 1.56 (s, 3 H, CH3).
13C NMR (100 MHz, DMSO-d6): δ = 159.8, 154.1, 153.1, 140.3,
136.3, 126.6, 126.6, 114.5, 112.3, 103.2, 50.4, 18.0.
IR (KBr): 3072, 2572, 1496, 1282 cm–1.
1H NMR (400 MHz, CDCl3): δ = 7.38 (t, J = 8.5 Hz, 2 H, HAr), 7.31
(d, J = 7.7 Hz, 2 H, HAr), 7.15 (t, J = 7.2 Hz, 1 H, HAr), 6.97 (dt,
J = 7.1, 2.4 Hz, 1 H, SO2CH), 6.75 (dt, J = 7.1, 2.0 Hz, 1 H,
CH2CH), 4.44 (t, J = 2.2 Hz, 2 H, CH2CH).
MS (ESI): m/z = 278 [M + H]+.
Anal. Calcd for C13H11NO4S: C, 56.31; H, 4.00; N, 5.05. Found: C,
56.22; H, 3.92; N, 5.13.
13C NMR (100 MHz, CDCl3): δ = 136.6, 133.9, 129.8, 127.7, 124.5,
118.6, 50.8.
MS (ESI): m/z = 196 [M + H]+.
2-(2-Oxo-2H-1-benzopyran-6-yl)-2,3-dihydroisothiazole 1,1-Di-
oxide (3d)
Following the typical procedure for 3a using 2d (100 mg, 0.34
mmol), Grubbs II catalyst (15 mg, 5 mol%), and distilled toluene
Synthesis 2014, 46, 368–374
© Georg Thieme Verlag Stuttgart · New York

PAPER
Sultams by Ring-Closing Metathesis
373
Anal. Calcd for C9H9NO2S: C, 55.37; H, 4.65; N, 7.17. Found: C,
55.46; H, 4.59; N, 7.28.
CH2CH3), 3.85–3.79 (q, J = 7.2 Hz, 2 H, CH2CH3), 1.32 (t, J = 7.2
Hz, 3 H, CH2CH3), 1.20 (t, J = 7.1 Hz, 3 H, CH2CH3).
13C NMR (100 MHz, CDCl3): δ = 160.6, 150.2, 143.2, 136.1, 126.4,
108.5, 52.0, 45.4, 37.2, 14.4, 12.8.
MS (ESI): m/z = 286 [M + H]+.
2-(4-Methylphenyl)-2,3-dihydroisothiazole 1,1-Dioxide (3h)
Following the typical procedure for 3a using 2h (100 mg, 0.42
mmol), Grubbs II catalyst (18 mg, 5 mol%), and distilled toluene
(10 mL). The crude product was purified by column chromatogra-
phy (silica gel, 50% EtOAc–PE) to afford 3h (78 mg, 88%) as a
white solid; mp 158–161 °C; Rf = 0.50 (50% EtOAc–PE).
Anal. Calcd for C11H15N3O4S: C, 46.31; H, 5.30; N, 14.73. Found:
C, 46.44; H, 5.39; N, 14.69.
IR (KBr): 3083, 2339, 1610, 1284 cm–1.
Acknowledgement
1H NMR (400 MHz, CDCl3): δ = 7.24–7.17 (m, 4 H, HAr), 6.96 (dt,
J = 7.1, 3.1 Hz, 1 H, SO2CH), 6.74 (dt, J = 7.1, 1.9 Hz, 1 H,
CH2CH), 4.41 (t, J = 2.4 Hz, 2 H, CH2CH), 2.32 (s, 3 H, CH3).
13C NMR (100 MHz, CDCl3): δ = 134.8, 134.1, 133.8, 130.3, 127.6,
119.9, 51.4, 20.9.
DST, Government of India, is gratefully acknowledged for giving a
research grant to S.M. through INSPIRE Faculty Award (No.
IFA12/CH/56) and S.D. is thankful to DST, for providing a junior
research fellowship under the same project. We also thank Nilanjan
Majumder (Indian Institute of Chemical Technology, Hyderabad)
for ESI Mass Spectroscopy.
MS (ESI): m/z = 232 [M + Na]+.
Anal. Calcd for C10H11NO2S: C, 57.39; H, 5.30; N, 6.69. Found: C,
57.28; H, 5.38; N, 6.65.
Supporting Information for this article is available online at
2-(2-Pyridyl)-2,3-dihydroisothiazole 1,1-Dioxide (3i)
http://www.thieme-connect.com/ejournals/toc/synthesis. Included
Following the typical procedure for 3a using 2i (100 mg, 0.45
mmol), Grubbs II catalyst (19 mg, 5 mol%), and distilled toluene
(10 mL). The crude product was purified by column chromatogra-
phy (silica gel, 70% EtOAc–PE) to afford 3i (52 mg, 60%) as a
white solid; mp 103–106 °C; Rf = 0.45 (70% EtOAc–PE).
are copies of 1H and 13C NMR spectra of all new compounds.SnuIofigp
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References and Notes
(1) Dauban, P.; Dodd, R. H. Tetrahedron Lett. 2001, 42, 1037.
(2) Wanner, J.; Harned, A. M.; Probst, D. A.; Poon, K. W. C.;
Klein, T. A.; Snelgrove, K. A.; Hanson, P. A. Tetrahedron
Lett. 2002, 43, 917.
(3) Enders, D.; Moll, A.; Bats, J. W. Eur. J. Org. Chem. 2006,
1271.
(4) For recent reviews on sultam and sultone chemistry, see:
(a) Majumdar, K. C.; Mondal, S. Chem. Rev. 2011, 111,
7749. (b) Mondal, S. Chem. Rev. 2012, 112, 5339.
(c) Scozzafava, A.; Owa, T.; Mastrolorenzo, A.; Supuran, C.
T. Curr. Med. Chem. 2003, 10, 925. (d) McReynolds, M. D.;
Dougherty, J. M.; Hanson, P. R. Chem. Rev. 2004, 104,
2239.
(5) (a) Miller, R. A.; Humphrey, G. R.; Lieberman, D. R.;
Ceglia, S. S.; Kennedy, D. J.; Grabowski, E. J. J.; Reider, P.
J. J. Org. Chem. 2000, 65, 1399. (b) Katritzky, A. R.; Wu, J.;
Rachwal, S.; Rachwal, B.; Macomber, D. W.; Smith, T. P.
Org. Prep. Proced. Int. 1992, 24, 463.
(6) Inagaki, M.; Tsuri, T.; Jyoyama, H.; Ono, T.; Yamada, K.;
Kobayashi, M.; Hori, Y.; Arimura, A.; Yasui, K.; Ohno, K.;
Kakudo, S.; Koizumi, K.; Suzuki, R.; Kato, M.; Kawai, S.;
Matsumoto, S. J. Med. Chem. 2000, 43, 2040.
(7) Zhuang, L.; Wai, J. S.; Embrey, M.; Fisher, T. E.; Egbertson,
M. S.; Payne, L. S.; Guare, J. P.; Vacca, J. P.; Hazuda, D. J.;
Felock, P. J.; Wolfe, A. L.; Stillmock, K. A.; Witmer, M. V.;
Moyer, G.; Schleif, W. A.; Gabryelski, L. J.; Leonard, Y. M.;
Lynch, J. J.; Michelson, S. R.; Young, S. S. J. Med. Chem.
2003, 46, 453.
IR (KBr): 2923, 2339, 1290, 1139 cm–1.
1H NMR (400 MHz, CDCl3): δ = 8.33 (d, J = 4.2 Hz, 1 H, HAr), 7.69
(td, J = 8.6, 1.6 Hz, 1 H, HAr), 7.43(d, J = 8.4 Hz, 1 H, HAr), 7.04–
7.00 (m, 2 H, HAr, SO2CH), 6.76 (d, J = 7.0 Hz, 1 H, CH2CH), 4.74
(s, 2 H, CH2CH).
13C NMR (100 MHz, CDCl3): δ = 149.5, 148.4, 138.4, 134.6, 127.4,
118.8, 111.3, 49.6.
MS (ESI): m/z = 197 [M + H]+.
Anal. Calcd for C8H8N2O2S: C, 48.97; H, 4.11; N, 14.28. Found: C,
49.09; H, 4.16; N, 14.21.
2-(1,3-Dimethyl-2,4-dioxo-1,2,3,4-tetrahydropyrimidin-5-yl)-
2,3-dihydroisothiazole 1,1-Dioxide (3j)
Following the typical procedure for 3a using 2j (100 mg, 0.35
mmol), Grubbs II catalyst (15 mg, 5 mol%), and distilled toluene
(10 mL). The crude product was purified by column chromatogra-
phy (silica gel, 70% EtOAc–PE) to afford 3j (83 mg, 92%) as a
white solid; mp 149–152 °C; Rf = 0.30 (70% EtOAc–PE).
IR (KBr): 3074, 1660, 1448, 1288 cm–1.
1H NMR (400 MHz, CDCl3): δ = 7.60 (s, 1 H, CH), 6.98 (d, J = 6.8
Hz, 1 H, SO2CH), 6.80 (d, J = 7.2 Hz, 1 H, CH2CH), 4.46 (s, 2 H,
CH2CH), 3.40 (s, 3 H, NCH3), 3.30 (s, 3 H, NCH3).
13C NMR (100 MHz, CDCl3): δ = 161.0, 151.0, 144.5, 136.2, 126.3,
108.0, 51.9, 37.4, 28.3.
MS (ESI): m/z = 258 [M + H]+.
Anal. Calcd for C9H11N3O4S: C, 42.02; H, 4.31; N, 16.33. Found:
C, 42.12; H, 4.22; N, 16.39.
(8) Leniger, T.; Wiemann, M.; Bingmann, D.; Widman, G.;
Hufnagel, A.; Bonnet, U. Epilepsia 2002, 43, 469.
(9) Storer, R. I.; Takemoto, T.; Jackson, P. S.; Brown, D. S.;
Baxendale, I. R.; Ley, S. V. Chem. Eur. J. 2004, 10, 2529.
(10) Davison, E. C.; Fox, M. E.; Holmes, A. B.; Roughley, S. D.;
Smith, C. J.; Williams, G. M.; Davies, J. E.; Raithby, P. R.;
Adams, J. P.; Forbes, I. T.; Press, N. J.; Thompson, M. J.
J. Chem. Soc., Perkin Trans. 1 2002, 1494.
(11) (a) Bravo, R. D.; Canepa, A. A. Synth. Commun. 2002, 32,
3675. (b) Orazi, O. O.; Corral, R. A.; Bravo, R. Heteroat.
Chem. 1986, 23, 1701.
(12) Lee, J.; Zhong, Y.-L.; Reamer, R. A.; Askin, D. Org. Lett.
2003, 5, 4175.
2-(1,3-Diethyl-2,4-dioxo-1,2,3,4-tetrahydropyrimidin-5-yl)-2,3-
dihydroisothiazole 1,1-Dioxide (3k)
Following the typical procedure for 3a using 2k (100 mg, 0.32
mmol), Grubbs II catalyst (14 mg, 5 mol%), and distilled toluene
(10 mL). The crude product was purified by column chromatogra-
phy (silica gel, 70% EtOAc–PE) to afford 3k (83 mg, 91%) as a col-
orless liquid; Rf = 0.40 (70% EtOAc–PE).
IR (KBr): 3074, 2327, 1652, 1288 cm–1.
1H NMR (400 MHz, CDCl3): δ = 7.57 (s, 1 H, CH), 6.99 (dt, J = 7.1,
2.3 Hz, 1 H, SO2CH), 6.81 (dt, J = 7.1, 2.3 Hz, 1 H, CH2CH), 4.49
(t, J = 2.4 Hz, 2 H, CH2CH), 4.00–3.95 (q, J = 7.1 Hz, 2 H,
© Georg Thieme Verlag Stuttgart · New York
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S. Mondal, S. Debnath
PAPER
(13) Chiacchio, U.; Corsaro, A.; Rescifina, A.; Bkaithan, M.;
Grassi, G.; Piperno, A.; Privitera, T.; Romeo, T. G.
Tetrahedron 2001, 57, 3425.
Tarrade, A.; Dodd, R. H. J. Am. Chem. Soc. 2001, 123, 7707.
(d) Zeng, W.; Chemler, S. R. J. Am. Chem. Soc. 2007, 129,
12948.
(14) (a) Metz, P.; Seng, D.; Fröhlich, R. Synlett 1996, 741.
(b) Rogachev, V. O.; Metz, P. ARKIVOC 2007, (v), 167.
(c) Rogatchov, V. O.; Bernsmann, H.; Schwab, P.; Fröhlich,
R.; Wibbeling, B.; Metz, P. Tetrahedron Lett. 2002, 43,
4753. (d) Plietker, B.; Seng, D.; Fröhlich, R.; Metz, P.
Tetrahedron 2000, 56, 873. (e) Rogachev, V. O.; Filimonov,
V. D.; Fröhlich, R.; Kataeva, O.; Metz, P. Heterocycles
2006, 67, 589. (f) Greig, I. R.; Tozer, M. J.; Wright, P. T.
Org. Lett. 2001, 3, 369.
(18) (a) Liang, J.-L.; Yuan, S.-X.; Chan, P. W. H.; Che, C.-M.
Org. Lett. 2002, 4, 4507. (b) Padwa, A.; Flick, A. C.;
Leverett, C. A.; Stengel, T. J. Org. Chem. 2004, 69, 6377.
(19) Hanessian, S.; Sailes, H.; Therrien, E. Tetrahedron 2003, 59,
7047.
(20) Freitag, D.; Schwab, P.; Metz, P. Tetrahedron Lett. 2004, 45,
3589.
(21) Preston, A. J.; Gallucci, J. C.; Paquette, L. A. J. Org. Chem.
2006, 71, 6573.
(15) (a) Vasudevan, A.; Tseng, P. S.; Djuric, S. W. Tetrahedron
Lett. 2006, 47, 8591. (b) Merten, S.; Fröhlich, R.; Kataeva,
O.; Metz, P. Adv. Synth. Catal. 2005, 347, 754. (c) Paquette,
L. A.; Barton, W. R. S.; Gallucci, J. C. Org. Lett. 2004, 6,
1313. (d) Paquette, L. A.; Dura, R. D.; Fosnaugh, N.;
Marshall, S. J. Org. Chem. 2006, 71, 8438.
(16) Liu, X.-Y.; Li, C.-H.; Che, C.-M. Org. Lett. 2006, 8, 2707.
(17) (a) Dauban, P.; Dodd, R. H. Org. Lett. 2000, 2, 2327.
(b) Sherman, E. S.; Chemler, S. R.; Tan, T. B.; Gerlits, O.
Org. Lett. 2004, 6, 1573. (c) Dauban, P.; Sanière, L.;
(22) Bressy, C.; Menant, C.; Piva, O. Synlett 2005, 577.
(23) Jeon, K. O.; Rayabarapu, D.; Rolfe, A.; Volp, K.; Omar, I.;
Hanson, P. R. Tetrahedron 2009, 65, 4992.
(24) Majumdar, K. C.; Mondal, S.; De, N. Synlett 2008, 2851.
(25) Majumdar, K. C.; Mondal, S.; De, N. Synthesis 2009, 3127.
(26) (a) Majumdar, K. C.; Mondal, S. Tetrahedron 2009, 65,
9604. (b) Majumdar, K. C.; Chattopadhyay, B.; Samanta, S.
Tetrahedron Lett. 2009, 50, 3178. (c) Majumdar, K. C.;
Chakravorty, S.; Shyam, P. K.; Taher, A. Synthesis 2009,
403.
Synthesis 2014, 46, 368–374
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