Transition-metal free synthesis of diaryl vinyl selenides: A simple synthetic approach with high selectivity

Article abstract of DOI:10.1016/j.tet.2014.03.011

A simple, highly efficient synthetic protocol is developed for the synthesis of unsymmetrical diaryl vinyl selenides from diaryldiselenide and β-bromo styrene under transition-metal free conditions in N,N′-dimethyl propylene urea and 130 °C to afford high yields and excellent selectivities. This method provides a new strategy to fabricate a wide variety of important substituted molecular skeletons and an alternative to conventionally used metal salts, additives, and ligands.

Full text of DOI:10.1016/j.tet.2014.03.011

Tetrahedron 70 (2014) 2699e2702
Contents lists available at ScienceDirect
Tetrahedron
journal homepage: www.elsevier.com/locate/tet
Transition-metal free synthesis of diaryl vinyl selenides: a simple
synthetic approach with high selectivity
Balaji Mohan, Sori Hwang, Hyunje Woo, Kang Hyun Park *
Department of Chemistry, Pusan National University, Busan 609735, South Korea
a r t i c l e i n f o
a b s t r a c t
Article history:
A simple, highly efficient synthetic protocol is developed for the synthesis of unsymmetrical diaryl vinyl
Received 24 January 2014
Received in revised form 28 February 2014
Accepted 4 March 2014
0
selenides from diaryldiselenide and
b
-bromo styrene under transition-metal free conditions in N,N -
ꢀ
dimethyl propylene urea and 130 C to afford high yields and excellent selectivities. This method pro-
vides a new strategy to fabricate a wide variety of important substituted molecular skeletons and an
alternative to conventionally used metal salts, additives, and ligands.
Available online 12 March 2014
Ó 2014 Elsevier Ltd. All rights reserved.
Keywords:
b
-Bromo styrene
Carboneselenium bond forming reactions
Diaryl vinyl selenide
High selectivity
Transition-metal free
1
. Introduction
usually accomplished with transition-metal catalysts such as pal-
3
4a,b
ladium and copper.
Such catalysts have been found to be in-
and L-
Introduction of new functionalities into diaryldiselenides
active without using indium salts and/or ligands such as PPh
3
(
PhSeSePh) is fascinating because of the formation of multipurpose
proline as additives or Zn dust as a reducing agent. In 1984, Tiecco
and colleagues reported that the nucleophilic addition of pre-
formed aryl selenide anions (from diphenyldiselenide) to vinyl
halides in good yields, which usually requires high equivalents of
2
C]C double bonds and a new sp carboneselenium bond. Diaryl
vinyl selenides1 have unlimited applications, and a simple and
facile synthetic procedure is desired by the researchers. Several
attempts have been made to carry out effective synthesis of vinyl
selenides.2 Some of the important techniques involve hydro-
selenation of alkynes, Wittig-type reaction, direct substitution
of a halogen atom on the double bond by benzeneselenoate
anions,2d oxidative zinc insertion of phenylselenyl halides , and
direct addition of diphenyldiselenide into alkenyl bromides. How-
4
c,d
strong base to attain a specific stereoisomer
with moderate
a
yields.
2
b
2c
Nevertheless, much attention has been focused particularly on
copper catalysts owing to their cost-effectiveness and commercial
2e
5
availability. The Ranu group used copper nanoparticles as catalyst
and Zn dust as a co-catalyst in water under reflux conditions. In this
reaction, high loading of copper nanoparticles and zinc dust are
essential to achieve good yields with high selectivity. Rao and co-
2
be2e
ever, the abovementioned procedures
are effective but un-
favorable in terms of atom economy, because they require the
preformation of organometallic reagents and produce a stoichio-
metric amount of metal waste. To achieve particular isomer, the
Raucher and Co., utilized the two-step process of addition of phe-
nylselenyl bromide to monosubstituted alkenes under thermody-
namically controlled conditions, followed by dehydrobromination
with the strong base and specific substituents on alkenes are im-
portant prerequisites. The synthesis of diphenylvinylselenides
from diphenyldiselenide precursors is interesting owing to its
moisture stability, low cost and easy of preparation.2g The activa-
tion of seleniumeselenium bond in diphenyldiselenide can be
6
workers also found that copper oxide nanoparticles combined
with a base as an additive promotes the coupling of diphenyldise-
lenide and trans-b-iodostyrene in DMSO. As expected, an iodo
compound is much more reactive than bromo compound even
7
under mild conditions. Braga et al. reported copper iodide pro-
moted synthesis of vinyl selenides by the cross-coupling of
diphenyldiselenide and potassium vinyltrifluoroborates as an al-
kene source without using any reducing agent.
However, even today, there are very few examples on the
preparation of vinyl selenides from diphenyldiselenide without
using a transition-metal catalyst. Therefore, transition-metal free
synthesis of vinyl selenides should be investigated in order to re-
solve problems such as the toxicity of transition metals and ligands,
2
f
*
Corresponding author. Tel.: þ82 51 510 2238; fax: þ82 51 980 5200; e-mail
address: chemistry@pusan.ac.kr (K.H. Park).
0
040-4020/$ e see front matter Ó 2014 Elsevier Ltd. All rights reserved.
http://dx.doi.org/10.1016/j.tet.2014.03.011

2700
B. Mohan et al. / Tetrahedron 70 (2014) 2699e2702
contamination of the products, and the concomitant formation of
side products. While looking for the relevant literature references,
we were surprised to find a report by Ogawa et al., which states that
phenyl selenylvinyl)-benzene with the highest selectivity for
trans-stereoisomer (97%). As shown in Table 1, among the solvents
examined, DMPU showed excellent yields, whereas DMF, DMA,
and NMP were less successful. No reaction took place in other
solvents such as dioxane, dimethoxyethane, acetonitrile, THF, and
toluene.
The addition of CuO nanopowder failed to improve the selec-
tivity (entry 11, Table 1), which shows no value of added transition-
metal catalysts under the present conditions. In the case of entry
12, a combination of CuO nanopowder and zinc dust greatly en-
hances the formation of di(4-methyl-phenyl) selenideside product
diphenyldiselenide could be successfully coupled with
styrene to provide diphenyl vinyl selenide.
b-bromo
With E/Z ratio of 80:20 under transition-metal free conditions
using toxic hexamethylphosphoramide as a solvent at elevated
temperatures. A key problem associated with the transition-metal
free reaction is the loss of trans-selectivity. Therefore, it is highly
desirable to develop an efficient, atom economic, and environ-
mentally friendly synthetic method to attain high stereoselectivity
with good yields.
and as a consequence the yield is poorer. A reaction with b-bromo
9
styrene enriched with trans-product (98%) (entry13, Table 1) led to
the corresponding cross-coupled product with excellent improve-
ment of trans-selectivity (99.24%). Traces of products were detected
when the reactions were performed under DMSO or solvent free
conditions (entries 1 and 14). Indeed, only starting materials were
2
. Results and discussion
Our extensive reinvestigation of Ogawa’s findings led to some
8
serendipitous results, which we describe here in detail. In this pa-
per, we disclose that the cross-coupling of diphenyldiselenide with
recovered when we place 1-bromo-1-propene instead of
styrene (entry 15, Table 1).
b-bromo
0
-bromo styrene (87:13, E/Z) using DMPU (N,N -dimethyl pro-
b
pylene urea) as a solvent in the absence of catalysts, ligands, ad-
ditives, and bases affords diphenylvinylselenides in high yield
Our final optimized conditions were proved to be compatible
with a wide array of substituted diselenides and -bromo sty-
b
(
97:3, E/Z) enriched with trans-isomer. To the best of our knowl-
renes (Scheme 2, Table 2). The model substrates 1a and 2a
y
edge, there has been no report on the synthesis of diphenylvi-
nylselenides from diphenyldiselenide precursor with high trans-
selectivity in the absence of metal catalysts.
The reaction is very easy to perform, because no catalysts, co-
catalysts, ligands, or bases are required. Bis(4-methyl-phenyl) dis-
afforded 3a in 91% yield in 6 h (Scheme 1). However, other
substrates (except for entry 1, Table 2, 6 h) required extended
reaction times (12 h). It is clear that there is no substantial sub-
stituent effect with diaryldiselenides containing p-methoxy, p-
chloro, or m-trifluoro methyl groups (entries 2,4, and 5); how-
ever, the trans-selectivity slightly decreased to 96% for o-meth-
yldiphenyldiselenide (entry 3). When comparing the yields, all
functionalities were well tolerated and provided vinylated
elenide and
b-bromo styrene were used as model substrates to
explore the reaction-optimization conditions (Scheme 1, Table 1).
products in excellent yields. The reactions of
with different substituents were also investigated, and a variety
of substituted -bromo styrenes were proved to be reactive un-
b-bromo styrenes
b
der the studied reaction conditions and led to good to excellent
yields. In general, styrenes containing o-methyl, o-methoxy, or p-
chloro substituents were readily coupled, and afforded the cor-
responding coupled products (entries 6, 8, and 9), while
a methoxy group at the para position (entry 7) makes the re-
action slightly sluggish, which led to a high selectivity and yield.
Scheme 1.
10
Excellent trans-selectivity has been reported for the products
obtained from substituted -bromo styrenes (entries 6, 8, and 9).
b
Table 1
Reaction optimizations
Unfortunately, no reaction takes place when phenyl vinylboronic
Temp E/Za
Yielda
acid and potassium trans-styryl trifluoroborate were used as
coupling partners instead of b-bromo styrene (entries 10 and 11).
Unfortunately, this methodology is failed to provide good yield in
Entry Solvent
Catalyst
1
2
3
4
5
6
7
8
9
1
1
1
DMSO
DMPU
DMF
DMA
130
Traces
130
130
130
130
97:3
94:6
97:3
97:3
91
76
81
83
NR
NR
NR
NR
NR
89
the case of diphenylsulfides and tellurides (Scheme 3) while
z
stereoselectivity seems excellent .
NMP
1,4-Dioxane
1,2-Dimethoxyethane
Acetonitrile
THF
Toluene
DMPU
Reflux
Reflux
Reflux
Reflux
Reflux
130
0
1
2
CuO (5 mol %)d
CuO/Zn dust
97:3
97:3
b
DMPU
130
80
Scheme 2.
(5 mol %/2 equiv)
1
1
1
3
4
5
DMPU
d
130
130
130
99.24:0.76 91c
Traces
We prefer GCeMS to measure accurate percentage of stereo-
isomers present in the product. We synthesized diphenylvinylse-
lenide using Ogawa’s procedure to compare with our report and
measured GCeMS (Figs. 1 and 2). We found that our report shows
e
DMPU
NR
a
b
c
Determined by GCeMS.
Di(4-methyl-phenyl) selenide as side product (20%).
-Bromo styrene (98:2).
CuO nanopowder (purchase from Aldrich, Cat. No. 544868), 6 h.
-Bromo-1-propene was used (an experiment with 1-bromo-1-propene with
1
b
high trans-isomer present in the product. In addition, H NMR
d
e
1
diphenyldiselenide didn’t proceed well under the present conditions).
y
Compounds numbers corrected as bold.
The cross-coupling reaction of bis(4-methyl-phenyl)
z
Experiments with diphenyl disulfides and ditellurides proceeded slowly with
diselenide(1 mmol) and
b-bromo styrene(2.2 mmol) in 4 mL
ꢀ
b
-bromo styrene in DMPU solvent at 130 C for 24 h afforded yields 22 and 33%,
respectively, with stereoselectivity 100 and 98.34% of trans-isomers.
ꢀ
DMPU at 130 C (Scheme 1) provided (E)-and (Z)-1-methyl-4-(2-

B. Mohan et al. / Tetrahedron 70 (2014) 2699e2702
2701
Table 2
Substrate scope of vinylation of diphenyldiselenides
0
R [E/Z]a
E/Za
Yielda
Entry
R
Product
1
2
3
H
H
H
H
98:2
97:3
96:4
93
94
98
OCH
3
CH
3
4
5
Cl
H
H
97:3
98:2
96
91
CF
3
Fig. 1. GCeMS analysis of Ogawa’s report.
6
7
8
H
H
H
CH
3
[99.8:0.2]
99.6:0.4
98:2
94
81
93
OCH
3
3
[100:0]
[100:0]
OCH
99.6:0.4
9
H
Cl [100:0]
99.6:0.4
95
1
0
CH
3
3
d
d
NR
NR
11
CH
Fig. 2. GCeMS analysis of our report.
a
Determined by GCeMS, yield (refer to diphenyldiselenide), and stereo-
selectivity based on average of two independent runs, 12 h.
4
4
. Experimental section
.1. General
Reagents were purchased from Aldrich Chemical Co., TCI and
Strem Chemical Co. and used as received. Reaction products were
analyzed by GCeMS (Shimadzu-QP2010 SE), IR (Shimadzu-Prestige
1
13
2
1), H NMR, and C NMR (Varian Mercury Plus, 300 MHz).
Chemical shift values were recorded as parts per million relative to
tetramethylsilane as an internal standard, unless otherwise in-
dicated, and coupling constants in Hertz. High-resolution mass
carried out at Korea Basic Science Institute (Daegu). Starting ma-
terials were synthesized from previously reported procedure (see
Supplementary data).
Scheme 3.
4
.2. General procedure for the synthesis of diaryl vinyl
x
selenides
3
analysis of 3a based on integration of distinct CH signals shows
4
2
.76% of Z-isomer, which is slightly higher than GCeMS report,
.36% (see ESI).
To a 10 mL sealed aluminum capped glass vial with septum,
charged diphenyldiselenide (50 mg, 0.1602 mmol), -bromo sty-
b
rene (64 mg, 0.3526 mmol), and DMPU (4 mL). The mixture was
3
. Conclusion
x
We included detailed experimental procedure in the experimental section of
In summary, we successfully achieved the transition-metal
the manuscript. The products obtained are identified by using GCeMS. The product
diphenyl vinyl selenide retention time and molecular weight vary with starting
materials diphenyldiselenide and
free synthesis of diaryl vinyl selenides by employing a suitable
ꢀ
temperature (130 C) and DMPU as a solvent. This simple syn-
b-bromo styrene. We used diphenyldiselenide as
thetic approach provides good functional-group tolerance and
high yields. In addition, we found that the E/Z ratio of the con-
version of b-bromo styrenes to coupled products can be greatly
enhanced or reproduced without metal catalysts, ligands, bases,
or additives.
limiting reagent while -bromo styrene in 2.2 equiv. The yield was calculated on
b
comparison with retention time and molecular weight of diphenyldiselenide and
diphenyl vinyl selenide, which includes presence of any side products. For example,
entry 12, Table 1 shows 80% yield, which corresponds to presence of side product
20%. In this case, no starting material was detected in GCeMS. So, we mentioned
80% as yield.

2702
B. Mohan et al. / Tetrahedron 70 (2014) 2699e2702
ꢀ
heated at 130 C under vigorous magnetic stirring for the indicated
time. After stirring for appropriate time, mixture was cooled to rt,
diluted with water, extracted with ether five times. The combined
ether layer was washed with water, dried with anhydrous sodium
sulfate, and concentrated in a rotary evaporator. The residue was
analyzed by GCeMS. After the GCeMS analysis, the crude product
was chromatographed on silica gel afforded the desired product.
4.2.8. (E) and (Z)-(4-Methoxystyryl)(phenyl)selenide (3h): [E/Z,
1
98:2]. H NMR (CDCl
6.99 (d, J¼15.9 Hz; 1H), 7.25e7.30 (m, 4H), 7.52e7.58 (m, 2H);
NMR (CDCl , 75 MHz) 55.5, 114.0, 114.3, 116.1, 127.3, 127.6, 129.5,
130.1, 131.0, 132.2, 136.1, 159.6. IR (neat), 3014, 2349, 1617, 1507,
14OSe 290.0208,
3
, 300 MHz) d 3.81 (s, 3H) 6.84e6.91 (m, 3H),
13
C
3
n
1246, 1036, 1171, 758. HRMS (EI) calcd for C15
found 290.0210.
H
4
.2.1. 1(E) and (Z)-(Styryl)(4-methyl-phenyl)selenide (3aa): [E/Z,
4.2.9. (E) and (Z)-(2-methoxystyryl)(phenyl)selenide (3i): [E/Z,
1
1
97:3]. H NMR (CDCl
3
, 300 MHz)
d
2.35 (s, 3H), 6.83 (d, J¼15.9 Hz;
98:2]. H NMR (CDCl
7.22e7.47 (m, 8H), 7.55e7.58 (m, 2H); C NMR (CDCl
111.2, 120.1, 120.9, 126.3, 127.3, 129.0, 129.4, 131.1, 131.3, 132.3, 156.7.
IR (neat), 3022, 2349, 1280, 1642, 761. HRMS (EI) calcd for
14OSe 290.0213, found 290.0210.
3
, 300 MHz) d3.85 (s, 3H), 6.87e6.96 (m, 2H),
13
13
1
H), 7.06e7.15 (m, 3H), 7.18e7.34 (m, 5H), 7.39e7.50 (m, 2H);
C
3
, 75 MHz)
NMR (CDCl
3
, 75 MHz)
d
21.5, 120.4, 124.7, 126.2, 127.6, 128.8, 130.3,
3022, 2366, 1600, 1482, 1432,
028, 952, 800, 725, 674. HRMS (EI) calcd for C15 14Se 274.0263,
133.3, 134.3, 137.3, 137.8. IR (neat),
n
n
1
H
15
C H
{
found 274.0261 .
4
.2.10. (E) and (Z)-(4-Chlorostyryl)(phenyl)selenide(3j): [E/Z,
.2.2. (E) and (Z)-(Styryl)(phenyl)selenide (3b): [E/Z, 98:2]. 1H NMR
CDCl , 300 MHz)
6.85 (d, J¼15.9 Hz; 1H), 7.15e7.42 (m, 9H),
.54e7.63 (m, 2H); C NMR (CDCl
27.8,127.9,128.5,128.6,128.8,129.3,129.5,130.3,131.7,132.7,132.9,
35.4,137.2. IR (neat), 3056, 2357,1583,1482,1440, 1028, 952, 733,
83. HRMS (EI) calcd for C14 12Se 260.0106, found 260.0104.
99.6:0.4]. H NMR (CDCl
(d, J¼15.6 Hz; 1H), 7.25e7.34 (m, 7H), 7.54e7.64 (m, 2H); C NMR
(CDCl , 75 MHz) 120.9, 127.4, 127.4, 127.9, 129.0, 129.4, 129.6,
129.9, 131.7, 133.1, 133.4, 135.7. IR (neat), 3022, 2357, 1591, 1491,
11ClSe 293.9718, found
1
, 300 MHz)
d
6.81 (d, J¼15.6 Hz; 1H), 7.15
4
(
7
1
1
6
3
13
3
d
1
3
3
, 75 MHz)
d
119.6, 126.2, 127.6,
3
d
n
n
1272, 960, 750, 683. HRMS (EI) calcd for C14
293.9714.
H
H
4
.2.3. (E) and (Z)-(Styryl)(4-methoxy-phenyl)selenide (3c): [E/Z,
1
Acknowledgements
97:3]. H NMR (CDCl
3
, 300 MHz)
d
3.82 (s, 3H), 6.74 (d, J¼15.6 Hz;
1
H), 6.90 (d, J¼8.7 Hz; 1H), 7.13 (d, J¼15.6 Hz; 1H), 7.20e7.42 (m,
13
This research was supported by Basic Science Research Program
through the National Research Foundation of Korea (NRF) funded
10H), 7.50e7.57 (m, 3H); C NMR (CDCl
3
, 75 MHz) 55.6, 115.2,
d
119.4, 121.3, 126.1, 127.5, 128.4, 128.8, 133.1, 135.3, 135.8,137.4, 159.9.
by the Ministry of Science, ICT
013R1A1A1A05006634) and the Research Fund Program of Re-
search Institute for Basic Sciences, Pusan National University, Korea,
013, Project No. RIBS-PNU-2012-201. K.H.P. thank to the TJ Park
& Future Planning (No.
IR (neat),
8
2
n
3006, 2374, 1718, 1591, 1482, 1289, 1255, 1171, 1028, 952,
14OSe 290.0208, found
2
34, 725, 691. HRMS (EI) calcd for C15
90.0210.
H
2
Junior Faculty Fellowship and LG Yonam Foundation.
4
9
1
1
.2.4. (E) and (Z)-(Styryl)(2-methyl-phenyl)selenide (3d): [E/Z,
1
6:4]. H NMR (CDCl
H), 7.12 (d, J¼15.6 Hz; 1H), 7.24e7.36 (m, 5H), 7.53 (d, J¼7.2 Hz;
3
, 300 MHz)
d
2.45 (s, 3H), 6.85 (d, J¼15.6 Hz;
Supplementary data
13
3
H); C NMR (CDCl , 75 MHz) d 22.5, 119.0, 126.2, 127.0, 127.8,
1
1
27.9, 128.2, 128.6, 128.8, 130.1, 130.4, 130.6, 131.0, 133.0, 135.3,
37.3, 139.9. IR (neat), 3014, 2366, 1768,1457, 1272,1171,1087, 750.
HRMS (EI) calcd for C15 14Se 274.0263, found 274.0261.
Copies of 1H, 13C NMR spectra, and GCeMS splitting pattern for
all compounds. Supplementary data associated with this article can
be found in the online version, at http://dx.doi.org/10.1016/
j.tet.2014.03.011.
n
H
4
9
.2.5. (E) and (Z)-Styryl(4-chloro-phenyl)selenide (3e): [E/Z,
7:3]. H NMR (CDCl
1
3
, 300 MHz)
d
6.69 (d, J¼9 Hz; 1H), 6.85 (d,
J¼15 Hz; 1H), 6.98 (d, J¼10.2 Hz; 1H), 7.09 (d, J¼15.9 Hz; 1H),
.25e7.52 (m, 10H); 13C NMR (CDCl
, 75 MHz) 118.8, 126.3, 128.1,
28.5, 128.6, 128.7, 128.9, 129.7, 133.9, 134.0, 134.2, 136.2, 137.0. IR
neat), 3022, 2349, 1474, 1103, 1011, 943, 809, 725, 683. HRMS (EI)
calcd for C14 11ClSe 293.9716, found 293.9714.
References and notes
7
1
(
3
d
1
. (a) Comasseto, J. V.; Petragnani, N. J. Organomet. Chem. 1978, 152, 295; (b) Co-
masseto, J. V. J. Organomet. Chem. 1983, 252, 131; (c) Comasseto, J. V.; Ling, L. W.;
Petragnani, N.; Stefani, H. A. Synthesis 1997, 373; (d) Han, L.-B.; Tanaka, M.
Chem. Commun. 1999, 395; (e) Wirth, T. Tetrahedron 1999, 55, 1; (f) Procter, D. J.
J. Chem. Soc., Perkin Trans. 1 2001, 335; (g) Ogawa, A. J. Organomet. Chem. 2000,
n
H
6
1
11, 463; (h) Freudendahl, D. M.; Shahzad, S. A.; Wirth, T. Eur. J. Org. Chem. 2009,
649.
2. (a) Perin, G.; Lenardao, E. J.; Jacob, R. G.; Panatieri, R. B. Chem. Rev. 2009, 109,
277; (b) Zeni, G.; Stracke, M. P.; Nogueira, C. W.; Braga, A. L.; Menzes, P. H.;
4
9
.2.6. (E) and (Z)-Styryl(3-trifluoromethyl-phenyl)selenide (3f): [E/Z,
1
8:2]. H NMR (CDCl
3
, 300 MHz)
d
7.01 (d, J¼15.6 Hz; 1H), 7.14 (d,
1
J¼15.9 Hz; 1H), 7.25e7.43 (m, 7H), 7.53 (d, J¼8.1 Hz; 1H), 7.69 (d,
13
Stefani, H. A. Org. Lett. 2004, 6, 1135; (c) Silveira, C. C.; Begnini, M. L.; Boeck, P.;
Braga, A. L. Synthesis 1997, 221; (d) Cristau, H. J.; Chabaud, B.; Labaudiniere, R.;
Christol, H. J. Org. Chem. 1986, 51, 875; (e) Santi, C.; Santoro, S.; Battistelli, B.;
Testaferri, L.; Tiecco, M. Eur. J. Org. Chem. 2008, 5387; (f) Raucher, S.; Hansen,
M. R.; Colter, M. A. J. Org. Chem. 1978, 43, 4885; (g) Taniguchi, N. Tetrahedron
J¼8.4 Hz; 1H), 7.78 (s, 1H); C NMR (CDCl
3
, 75 MHz)
d 117.6, 124.1,
1
2
3
24.3, 126.5, 128.3, 128.9, 129.8, 132.0, 135.3, 136.8, 137.6. IR (neat),
n
997, 2366, 1322, 1272, 1137, 750. HRMS (EI) calcd for C15
27.9977, found 327.9978.
H F
11 3
Se
2
012, 68, 10510.
3
4
. Ranu, B. C.; Chattopadhyay, K.; Banerjee, S. J. Org. Chem. 2006, 71, 423.
. (a) Goncalves, L. C.; Fiss, G. F.; Perin, G.; Alves, D.; Jacob, R. G.; Lenardao, E. J.
Tetrahedron Lett. 2010, 51, 6772; (b) Chang, D.; Bao, W. Synlett 2006, 1786; (c)
Tiecco, M.; Testaferri, L.; Tingoli, M.; Chianelli, D.; Montanacci, M. Tetrahedron
Lett. 1984, 43, 4975; (d) Bagnoli, L.; Scarponi, C.; Testaferri, L.; Tiecco, M. Tet-
rahedron: Asymmetry 2009, 20, 1506.
4
9
.2.7. (E) and (Z)-(4-Methylstyryl)(phenyl)selenide (3g): [E/Z,
9.6:0.4]. 1H NMR (CDCl
3
, 300 MHz) 2.35 (s, 3H), 6.93 (d,
d
J¼15.6 Hz; 1H), 7.11e7.18 (m, 3H), 7.25e7.36 (m, 5H), 7.54e7.58 (m,
1
3
2
1
(
H); C NMR (CDCl
3
, 75 MHz) 118.0,126.2,127.5,129.5,129.6,130.7,
3014, 2358, 1483, 1281, 759. HRMS
EI) calcd for C15H14Se 274.0263, found 274.0261.
5. (a) Saha, A.; Saha, D.; Ranu, B. C. Org. Biomol. Chem. 2009, 7, 1652.
34.5, 135.9, 137.8. IR (neat),
n
6. Reddy, V. P.; Kumar, A. V.; Rao, K. R. Chem. Lett. 2010, 39, 212.
7. Braga, A. L.; Barcellos, T.; Paixao, M. W.; Deobald, A. M.; Godoi, M.; Stefani, H. A.;
Cella, R.; Sharma, A. Organometallics 2008, 27, 4009.
. Ogawa, T.; Hayami, K.; Suzuki, H. Chem. Lett. 1989, 769.
. Chowdhury, S.; Roy, S. J. Org. Chem. 1997, 62, 199.
8
9
{
According to Tetrahedron format, we included general procedure, 1H, 13C, IR,
10. At present, we do not know the exact mechanism but assumed the reaction is
following S 2pathway. Our investigation is currently underway.
and HRMS data in the manuscript.
N