Iododecarboxylation of α-carboxylate, α-cinnamoyl ketene cyclic dithioacetals

Article abstract of DOI:10.1081/SCC-120014773

The iododecarboxylation reaction of α-carboxylate, α-cinnamoyl ketene cyclic dithioacetals 2 was successfully performed with iodine as halogenation reagent and in water insensitive media. This reaction provides a mild and efficient method for the preparat

Full text of DOI:10.1081/SCC-120014773

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IODODECARBOXYLATION OF α-CARBOXYLATE, α-
CINNAMOYL KETENE CYCLIC DITHIOACETALS
Mang Wang a , Xian-Xiu Xu a , Qun Liu b , Li Xiong a , Bin Yang a & Lian-Xun Gao c
a Department of Chemistry, Northeast Normal University, Changchun, 130024, P.R. China
b Department of Chemistry, Northeast Normal University, Changchun, 130024, P.R. China
c State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied
Chemistry, The Academy of Science of China, Changchun, 130022, P.R. China
Version of record first published: 22 May 2009.
To cite this article: Mang Wang , Xian-Xiu Xu , Qun Liu , Li Xiong , Bin Yang & Lian-Xun Gao (2002): IODODECARBOXYLATION
OF α-CARBOXYLATE, α-CINNAMOYL KETENE CYCLIC DITHIOACETALS, Synthetic Communications: An International Journal for
Rapid Communication of Synthetic Organic Chemistry, 32:22, 3437-3443
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SYNTHETIC COMMUNICATIONS
Vol. 32, No. 22, pp. 3437–3443, 2002
IODODECARBOXYLATION OF
a-CARBOXYLATE, a-CINNAMOYL
KETENE CYCLIC DITHIOACETALS
Mang Wang,1,2 Xian-Xiu Xu,1 Qun Liu,1, Li Xiong,1
*
Bin Yang,1 and Lian-Xun Gao2
1Department of Chemistry, Northeast Normal
University, Changchun, 130024, P.R. China
2State Key Laboratory of Polymer Physics and
Chemistry, Changchun Institute of Applied Chemistry,
the Academy of Science of China,
Changchun, 130022, P.R. China
ABSTRACT
The iododecarboxylation reaction of a-carboxylate, a-cinna-
moyl ketene cyclic dithioacetals 2 was successfully performed
with iodine as halogenation reagent and in water insensitive
media. This reaction provides a mild and efficient method for
the preparation of a-iodo, a-cinnamoyl ketene cyclic dithio-
acetals 3 which are important kinds of potential new
intermediates to be valued.
*Corresponding author.
3437
DOI: 10.1081/SCC-120014773
Copyright & 2002 by Marcel Dekker, Inc.
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3438
WANGET AL.
In one of our research on the iodolactonization of g,d-unsaturated
acids,[1] a-carboxylate, a-cinnamoyl ketene cyclic dithioacetals 2[2] were
selected as substrates to explore its synthetic utilization especially the
properties of cyclization. However, in the presence of iodine under basic
conditions—a common condition for iodolactonization reaction, the
products obtained were a-iodo, a-cinnamoyl ketene cyclic dithioacetals 3
which formed via iododecarboxylation instead of the iodolactonization
expected. Some recent works described that the halodecarboxylation
reaction of a,b-unsaturated carboxylates can be easily performed with halo-
genation reagents such as bis(sym-collidine) iodine(I) hexafluorophosphate
(BIH) other than molecular halogens in organic solvents.[3] Comparably, in
our experiments, the iododecarboxylation reaction of compounds 2 can
easily take place only using iodine as electrophilic reagent in aqueous
media. As far as we know, the iododecarboxylation reaction under our
experimental conditions is not well known.[4] Here we will present our
new experimental results (Sch. 1).
The substrates 2 were prepared in high yields (>80%) according our
method as described in Sch. 1.[5] In a typical reaction, to a solution of
a-carboxylate, a-cinnamoyl ketene cyclic dithioacetal 2a (1 mmol in 5 mL
CH2Cl2) were added 1 mL saturated NaHCO3 aqueous and then iodine
(1.5 mmol) at room temperature. After stirred at room temperature for
0.5 h, substrate 2a disappeared (monitored by TLC). The reaction was
then quenched with 5 mL saturated Na2S2O3 aq and the product was
extracted with CH2Cl2. The organic phase was dried over anhydrous
MgSO4, filtered, and concentrated under reduced pressure. Then the residue
was purified by recrystallization from diethyl ether–ethyl acetate (v/v ¼ 5:1)
to afford a-iodo, a-cinnamoyl ketene cyclic dithioacetal 3a in 90% yield.
Satisfactory results were obtained for all substrates studied. The experi-
mental results are listed in Table 1. Compared with the works reported in
this research area, the iododecarboxylation reaction we described here can
be run at very mild reaction conditions: in water insensitive solvents, at
room temperature, catalyzed by the handy catalyst and with high yields.
The most importance of all is that the products 3 are important kinds of
potential new intermediates to be valued in the future.
Scheme 1.

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KETENE CYCLIC DITHIOACETALS
Table 1. Iododecarboxylation Reaction of 2 with Iodinea
3439
Reaction Time
(h)
Yields of
3 (%)b
Entry
n
Ar
Products
1
2
3
4
5
6
7
8
9
1
1
1
1
1
2
2
2
2
2
1
C6H5
3a
3b
3c
3d
3e
3f
3g
3h
3i
0.5
4.0
3.0
4.5
1.0
2.0
6.0
0.25
6.0
2.0
36.0
90
95
90
96
82
77
95
88
89
85
83
p-CH3OC6H4
3,4-OCH2OC6H3
p-NO2C6H4
2-Furanyl
C6H5
p-CH3OC6H4
3,4-OCH2OC6H3
p-NO2C6H4
2-Furanyl
10
11c
3j
4a
C6H5
aIododecarboxylation: 2 (1 mmol), saturated NaHCO3 aq. (1 mL), CH2Cl2 (5 mL),
I2 (1.5 mol).
bIsolated yields.
cIn this case, only decarboxylation took place: 2 (1 mmol), CH2Cl2 (5 mL), I2
(1.5 mol).
Scheme 2.
The mechanism about the conversion from 2 to 3 is believed to be via a
carboncation intermediate (Sch. 2). At first, compound 2 is converted into
carboxylate anion under basic conditions. Then electrophilic attacking of
iodine at a-carbon took place to give carboncation intermediate II in which
the positive charge is strongly stabilized by the two adjacent sulfur
atoms[3a,6,7] and the carbon–carbon bond between carboxyalte and

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3440
WANGET AL.
a-carbon is weakened. As the result, the elimination of carbon dioxide
from II drives this reaction to product 3.
In our experiment, the reaction can be accelerated by the addition of
NaHCO3 is found. The reason why this iododecarboxylation reaction took
place so easily under basic condition should be due to the electron density of
carbon–carbon double bond of ketene dithioacetals which can be strengthen
by the carboxylate and thus favored to the electrophilic attacking. We also
tried to examine if iododecarboxylation reaction could take place without
NaHCO3. The results were significantly different. When 2a was selected as
substrate, only decarboxylated compound 4a was obtained in 83% yield
(Entry 11) instead of the product 3a. When the other substrates 2 were
used, the reaction were very complex and so many products were formed
that the attempted separation failed. In our continuing works, we are to
choose bromine as halogenation reagent to perform bromodecarboxylation
reaction of a-carboxyalte ketene cyclic dithioacetals. The exploration of
this halodecarboxylation to some range of those alkyalthio groups and
a-substituted groups for compounds 2 and the application of the new
intermediates 3 are in progress.
In summary, we have reported here a good method for the preparation
of a-iodo, a-cinnamoyl ketene cyclic dithioacetals, a kinds of potential
important intermediates, from a-carboxylate, a-cinnamoyl ketene cyclic
dithioacetals via iododecarboxylation reaction. As the complementary to
the Hunsdiecker reaction, this iododecarboxylation reaction can efficiently
run under more milder conditions.
IRspectra (KBr) were measured using a MAGNA-IR560 spectrom-
1
eter. The H NMRspectra were determined on a BRUKERAC spectrom-
eter (80 MHz) or VARIAN UNITY spectrometer (400 MHz) in CDCl3 with
TMS as internal standard. Mass spectra were recorded on LCQ spectrom-
eter. Elemental analyses were obtained on a PE-2400 analyser. Unless
otherwise noted materials were obtained from commercially available
sources and used without further purification. The preparation of substrates
2 was following the known procedure[5] through the aldol condensation
reaction of compounds 1 with aryl aldehydes under basic condition and
the process for iododecarboxylation reaction of compounds 2a–j has been
described in the text.
1
3a: H NMR(400 MHz): 3.43 (2H, t, J ¼ 6.6 Hz, SCH2), 3.80 (2H, t,
J ¼ 6.6 Hz, SCH2), 7.40 (3H, m, 3 Â ArH), 7.61 (2H, m, 2 Â ArH), 7.65 (1H, d,
J ¼ 15.6 Hz, ¼CH), 7.78 (1H, d, J ¼ 15.6 Hz, ¼CH); IR(KBr): 3108, 2920,
2855, 1632, 1568, 1495, 1435, 1413; MS for [C13H11IOS2 þ Na]þ: 397.2; Anal.
calcd. for C13H11IOS2: C, 41.72; H, 2.96. Found: C, 41.58; H, 2.88.
1
3b: H NMR(400 MHz): 3.43 (2H, t, J ¼ 6.6 Hz, SCH2), 3.79 (2H, t,
J ¼ 6.6 Hz, SCH2), 3.85 (3H, s, OCH3), 6.92 (2H, d, J ¼ 8.8 Hz, 2 Â ArH),

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KETENE CYCLIC DITHIOACETALS
3441
7.57 (2H, d, J ¼ 8.8 Hz, 2 Â ArH), 7.60 (1H, d, J ¼ 15.6 Hz, ¼CH), 7.69 (1H,
d, J ¼ 15.6 Hz, ¼CH); IR(KBr): 3080, 3030, 2924, 1632, 1601, 1559, 1509,
1418, 1286, 1248, 1161; Anal. calcd. for C14H13IO2S2: C, 41.59; H, 3.24.
Found: C, 41.66; H, 3.27.
3c: 1H NMR(80 MHz): 3.40 (2H, m, SCH 2), 3.76 (2H, m, SCH2), 6.00
(2H, s, CH2), 6.80 (1H, d, J ¼ 8.8 Hz, ArH), 7.10 (1H, s, ArH), 7.12
(1H, d, J ¼ 8.8 Hz, ArH), 7.16 (1H, d, J ¼ 15.6 Hz, ¼CH), 7.67 (1H, d,
J ¼ 15.6 Hz, ¼CH); IR(KBr): 3070, 2940, 1630, 1563, 1500, 1445, 1245,
1170; Anal. calcd. for C14H11IO3S2: C, 40.20; H, 2.65. Found: C, 40.12;
H, 2.59.
3d: 1H NMR(80 MHz): 3.44 (2H, m, SCH 2), 3.63 (2H, m, SCH2), 7.59
(1H, d, J ¼ 15.6 Hz, ¼CH), 7.71 (2H, d, J ¼ 8.8 Hz, 2 Â ArH), 7.89 (1H, d,
J ¼ 15.6 Hz, ¼CH), 8.20 (2H, d, J ¼ 8.8 Hz, 2 Â ArH); IR(KBr): 3080, 3030,
2923, 1757, 1635, 1513, 1489, 1420, 1341, 1310, 1279; Anal. calcd.
for C13H10INO3S2: C, 37.24; H, 2.40; N, 3.34. Found: C, 37.09; H, 2.44;
N, 3.41.
1
3e: H NMR(80 MHz): 3.40 (2H, t, J ¼ 6.6 Hz, SCH2), 3.79 (2H, t,
J ¼ 6.6 Hz, SCH2), 6.48 (1H, m, ArH), 6.65 (1H, m, ArH), 7.35 (1H, d,
J ¼ 15.4 Hz, ¼CH), 7.49 (1H, m, ArH), 7.67 (1H, d, J ¼ 15.4 Hz, ¼CH);
IR(KBr): 3070, 3030, 2915, 1634, 1548, 1475, 1424, 1308, 1278; Anal.
calcd. for C11H9IO2S2: C, 36.27; H, 2.49. Found: C, 36.40; H, 2.41.
1
3f: H NMR(80 MHz): 2.19 (2H, m, CH ), 2.90 (2H, t, J ¼ 7.2 Hz,
2
SCH2), 3.09 (2H, t, J ¼ 7.2 Hz, SCH2), 7.33–7.54 (6H, m, 5 Â ArH þ
¼CH), 7.67 (1H, d, J ¼ 15.6 Hz, CH); IR(KBr): 3079, 3030, 1635, 1595,
1513, 1490, 1420, 1342, 1310, 1279, 1165; Anal. calcd. for C14H13IOS2: C,
43.31; H, 3.37. Found: C, 43.29; H, 3.46.
1
3g: H NMR(400 MHz): 2.18 (2H, m, CH ), 2.89 (2H, t, J ¼ 6.8 Hz,
2
SCH2), 3.09 (2H, t, J ¼ 6.8 Hz, SCH2), 3.83 (3H, s, OCH3), 6.90 (2H, d,
J ¼ 8.8 Hz, 2 Â ArH), 7.32 (1H, d, J ¼ 15.4 Hz, ¼CH), 7.48 (2H, d,
J ¼ 8.8 Hz, 2 Â ArH), 7.63 (1H, d, J ¼ 15.4 Hz, ¼CH); IR(KBr): 3085,
3039, 2925, 1629, 1600, 1558, 1507, 1422, 1325, 1253, 1144; Anal. calcd.
for C15H15IO2S2: C, 43.07; H, 3.61. Found: C, 42.88; H, 3.40.
1
3h: H NMR(400 MHz): 2.17 (2H, m, CH ), 2.90 (2H, t, J ¼ 7.0 Hz,
2
SCH2), 3.09 (2H, t, J ¼ 7.0 Hz, SCH2), 6.00 (2H, s, OCH2O), 6.80 (1H, d,
J ¼ 8.8 Hz, ArH), 7.03 (1H, s, ArH), 7.05 (1H, d, J ¼ 8.8 Hz, ArH), 7.27
(1H, d, J ¼ 15.4 Hz, ¼CH), 7.58 (1H, d, J ¼ 15.4 Hz, ¼CH); IR(KBr):
3070, 3010, 2915, 1632, 1567, 1409, 1446, 1300, 1274; Anal. calcd. for
C15H13IO3S2: C, 41.68; H, 3.03. Found: C, 41.89; H, 3.15.
3i: 1H NMR(400 MHz): 2.25 (2H, m, CH ), 2.94 (2H, t, J ¼ 7.0 Hz,
2
SCH2), 3.13 (2H, t, J ¼ 7.0 Hz, SCH2), 7.62 (1H, d, J ¼ 15.4 Hz, ¼CH), 7.70
(1H, d, J ¼ 15.4 Hz, ¼CH), 7.73 (2H, d, J ¼ 8.8 Hz, 2 Â ArH), 8.26 (2H, d,
J ¼ 8.8 Hz, 2 Â ArH); IR(KBr): 3096, 3070, 2923, 1634, 1592, 1575, 1508,

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3442
WANGET AL.
1335, 1279; Anal. calcd. for C14H12INO3S2: C, 38.81; H, 2.79; N, 3.23.
Found: C, 38.68; H, 2.62; N, 3.31.
1
3j: H NMR(80 MHz): 2.18 (2H, m, CH ), 2.90 (2H, t, J ¼ 7.0 Hz,
2
SCH2), 3.17 (2H, t, J ¼ 7.0 Hz, SCH2), 6.46 (1H, m, ArH), 6.64 (1H, m,
ArH), 7.25–7.49 (3H, m, ArH þ 2 Â ¼CH); IR(KBr): 3112, 2923, 2857,
1635, 1579, 1542, 1456, 1262, 1122; Anal. calcd. for C12H11IO2S2:
C, 38.10; H, 2.93. Found: C, 38.19; H, 3.06.
ACKNOWLEDGMENTS
We greatly thank NSFC (29862004) for the financial support.
REFERENCES
1. For a comprehensive review about iodolactonization reaction see (a)
Bartlett, P.A. Asymmetric Synthesis; Morrison, J.D., Ed.; Academic
Press: San Diego, 1984; 3, chap. 6; (b) Cardillo, G.; Orena, M.
Tetrahedron 1990, 46, 3321; (c) Harding, K.E.; Tiner, T.H.
Comprehensive Organic Synthesis; Trost, B.M., Fleming, I., Ed.;
Pergamon Press: Oxford, 1991; 4, 363–421.
2. Compounds 2 were derived from compounds 1 which are important
intermediates in organic synthesis and for a comprehensive review
about these kinds of intermediates please to see (a) Dieter, R.K.
Tetrahedron 1986, 42, 3029; (b) Junjappa, H.; Ila, H.; Asokan, C.V.
Tetrahedron 1990, 46, 5423; (c) Liu, Q.; Yang, Z.Y. YouJi HuaXue
(Chinese) 1992, 12, 225; (d) Wang, M.; Liu, Q.; Zhao, M.X.; Li, J.X.
J. Northeast Normal University (Chinese) 1999, 31(4), 48.
3. (a) Homsi, F.; Rousseau, G. Tetrahedron Lett. 1999, 40, 1495; (b)
Chowdhury, S.; Roy, S. J. Org. Chem. 1997, 62, 199; (c) Nasakar, D.;
Roy, S. J. Org. Chem. 1999, 64, 6896; (d) Homsi, F.; Rousseau, G.
J. Org. Chem. 1999, 64, 81.
4. (a) Reimer, M.; Tobin, E. J. Am. Chem. Soc. 1941, 63, 2490; (b) Cohen,
M.T.; McNelis, E. J. Org. Chem. 1984, 49, 515.
5. (a) Li, J.X.; Liu, Q.; Zhao, M.X.; Liu, J.F.; Li, S.Y.; He, Y. Chinese
Chem. Lett. 1998, 9, 21; (b) Liu, Q.; Li, J.X.; Liu, J.F.; Sun, Z.G.;
Xing, Y.; Jia, H.Q.; Lin, Y.Q. Hua Xue Xue Bao (Chinese) 2000, 58, 92.
6. Gill, S.; Kocienski, P.; Kohler, A.; Pontiroli, A.; Liu, Q. Chem.
Commun. 1996, 1743.
7. Liu, Q.; Zhu, Z.M.; Yang, Z.Y.; Hu, Y.L.; Jing, F.Y.; Xiao, Y.W.
Chem. J. of Chinese Univ. (Chinese) 1993, 14, 1538.

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KETENE CYCLIC DITHIOACETALS
3443
8. Structure of 4a was identified as follows: (Jin, R-Z.; Wang, Z.L.; Qi, J.;
Yang, X.X.; Mu, Z.C.; Liu, Q. J. Northeast Normal University
(Chinese) 2001, 33(1), 52.)
Received in Japan July 18, 2001

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