An economical approach to the synthesis of unsaturated thiacrown ethers

Article abstract of DOI:10.1055/s-0030-1260066

The inexpensive starting material, 1,1-dichloroethylene, was used as a substitute for 1,2-dichloroethylene to synthesize unsaturated thiacrown ethers through the reaction of 1,1-dichloroethylene with sodium sulfide in the presence of a 15-crown-5 catalyst. Besides the compounds containing cis-carbon-carbon double bonds, two unsaturated thiacrown ethers each containing one trans-carbon-carbon double bond were also isolated. Georg Thieme Verlag Stuttgart New York.

Full text of DOI:10.1055/s-0030-1260066

2454
PAPER
An Economical Approach to the Synthesis of Unsaturated Thiacrown Ethers
An
E
conomical Ap
o
proach to th
n
e
Synthesis
o
g
f
U
nsaturate
-
d
T
hiacr
Q
own Ethers ing Sun, Jing-Kui Yang*
College of Chemistry and Chemical Engineering, Graduate University of Chinese Academy of Sciences, Beijing, 100049, P. R. of China
Fax +86(10)88256092; E-mail: jkyang@gucas.ac.cn
Received 25 March 2011; revised 29 April 2011
well-known unsaturated thiacrown ethers 1–8
Abstract: The inexpensive starting material, 1,1-dichloroethylene,
(Scheme 2). Moreover, we also obtained (E,Z,Z,Z,Z,Z)-
1,4,7,10,13,16-hexathiacyclooctadeca-2,5,8,11,14,17-
was used as a substitute for 1,2-dichloroethylene to synthesize un-
saturated thiacrown ethers through the reaction of 1,1-dichloroeth-
ylene with sodium sulfide in the presence of a 15-crown-5 catalyst.
hexaene (5b), which was mentioned in one of Kamigata’s
Besides the compounds containing cis-carbon–carbon double reports,4 and a new thiaheterocycle, (E,Z,Z,Z,Z,Z,Z)-
bonds, two unsaturated thiacrown ethers each containing one trans-
carbon–carbon double bond were also isolated.
1,4,7,10,13,16,19-heptathiacyclo-heneicosa-2,5,8,11,14,17,20-
heptaene (6b) was identified at the same time; no other
Key words: unsaturated thiacrown ether, 1,1-dichloroethylene,
economical approach, macrocyclic compounds, hydrogen anion
transfer
products were isolated except for some polymeric materi-
al.
S
Cl
Cl
S
Unsaturated thiacrown ethers are a class of multifunction-
al molecules that have received increasing attention in the
fields of organic and analytical chemistry. Their special
cavity sizes and restricted conformations determine the
high selectivity towards transition metals1,2 and metallo-
fullerene.3 Because the carbon–carbon double bonds of
unsaturated thiacrown ethers are more active than the cor-
responding saturated systems, their oxidation and photo-
chemical behavior naturally became the focus of interest.4
After the first unsaturated benzothiacrown ether was ob-
tained by Nakayama et al.,5 cis-1,2-dichloroethylene was
introduced to the synthesis of unsaturated thiacrown
ethers. In 2001, large-ring unsaturated thiacrown ethers
without substituents were synthesized for the first time by
Kamigata’s group by treating cis-1,2-dichloroethylene
with sodium sulfide.1 Soon afterwards, unsaturated sele-
nacrown ethers and their complexations with silver were
reported.6 In addition, some analogues containing similar
unsaturated segments also aroused the attention of a num-
ber of chemists.7 The elegant work reported by these au-
thors stimulated us to do further studies. However, cis-
1,2-dichloroethylene, the key reactant for preparing un-
saturated thiacrown ethers is very expensive. Fortunately,
1,1-dichloroethylene, which was used to construct car-
bon–carbon double bonds,8 was found to be a convenient
substitute in our experiments. This starting material could
be used with almost the same effect as cis-1,2-dichloro-
ethylene, while being sixteen to fifty times cheaper than
the latter (prices quoted by Sigma–Aldrich in the Chinese
mainland in April, 2011).
Na2S⋅9H2O
+
S
n = 0–7
S
n
Scheme 1 The originally expected reaction
Cl
+
Na2S⋅9H2O or Na2S + D2O
Cl
MeCN
15-crown-5 or PEG
S
S
S
S
S
S
S
n
S
S
S
+
S
S
S
S
S
n = 0–7
1–4
5a (cis), 6a (cis)
7–8
S
5b (trans)
6b (trans)
Scheme 2 Reaction of 1,1-dichloroethylene with Na2S·9H2O, or
Na2S and D2O and catalysts; no deuterated product was detected
The best total yield of unsaturated thiacrown ethers was
almost the same as that obtained by Kamigata et al.,1 nev-
ertheless, the price of 1,1-dichloroethylene is approxi-
mately 2 to 6% that of cis-1,2-dichloroethylene, which
reduces the cost greatly. Therefore, it is still an economi-
cally viable method for the preparation of unsaturated
thiacrown ethers. Most importantly, the total yields were
slightly better at higher temperature than those at room
temperature; the reactions were accelerated to completion
in only two hours at 80 °C (Table 1). In addition, some
studies with phase-transfer catalysts were also made in an
attempt to find less expensive and non- or low-toxic sub-
stitutes, such as polyethylene glycol, to replace 15-crown-
5. Experiments demonstrated that some polyethylene gly-
cols did indeed show a certain amount catalytic activity,
although the effect was not as good as with crown ether
We originally expected that the product shown in
Scheme 1 would be generated in this reaction, but, unex-
pectedly, the experiment resulted in the formation of the
SYNTHESIS 2011, No. 15, pp 2454–2458
x
x.
x
x
.
2
0
1
1
Advanced online publication: 10.06.2011
DOI: 10.1055/s-0030-1260066; Art ID: H33211SS
© Georg Thieme Verlag Stuttgart · New York

PAPER
An Economical Approach to the Synthesis of Unsaturated Thiacrown Ethers
2455
(Table 1). A comparison of the catalytic efficiency could To explore methods to synthesize halogenated unsaturat-
be ordered as: 15-crown-5 > PEG2000 > MPEG750 > ed thiacrown ethers, trichloroethylene and tetrachloroeth-
PEG300 > tetraethylene glycol dimethyl ether. Moreover, ylene were treated, respectively, with sodium sulfide
total yields increased with an increase in the amount of nonahydrate, which produced a polymerization product
catalyst. However, when the amount of 15-crown-5 was nearly completely. This polymer was slightly soluble in
increased to more than 0.4 equiv, no apparent improve- tetrahydrofuran (THF) and N,N-dimethylformamide
ment was observed. Additionally, increasing the concen- (DMF), and partially dissolved even in dimethylsulfoxide
tration of the reactants decreased the total yields of the (DMSO), which indicated the possible existence of cross-
products due to the formation of more polymeric materi- linked structures. Ikeda and co-workers have reported the
al.1,9
synthesis of poly(vinylene sulfide) from trans-1,2-dichlo-
roethylene and sodium sulfide nonahydrate in high con-
Table 1 Reactions of 1,1-Dichloroethylene with Sodium Sulfide Nonahydrate or Sodium Sulfide and Deuterium Oxide in Acetonitrile
Entry Conc.
(M)a
Time Temp
Cat.
Total
Ratioc
(h)
45
48
48
48
48
48
72
72
72
72
72
72
72
72
72
72
2
(°C)
r.t.
r.t.
r.t.
r.t.
r.t.
r.t.
r.t.
r.t.
r.t.
r.t.
r.t.
r.t.
r.t.
r.t.
r.t.
r.t.
50
(equiv)b
yield (%)
1
2
3
4
5a
6a
7
8
5b
6b
1d
2
10–3
10–3
10–3
10–3
A (0.4)
–
40
~0
36 (33)e
37
20
14
29
3
44
NA
39
35
30
11
38
3
~0
4
18
16
10
5
–
–
3
A (0.4)
A 0.5
4
4
5
7
4
~0
~0
~0
~0
~0
6
6
8
3
6
21
22
24
23
20
13
13
16
25
12
8
9
5
5
4
8
6
2
4
3
3
2
2
2
2
2
2
4
5
2×10–3
3×10–3
10–3
A (0.4)
A (0.4)
A (0.4)
B (0.05)
B (0.1)
B (0.2)
B (0.2)
C (0.15)
C (0.4)
C (0.5)
D (0.5)
E (0.4)
A (0.4)
A (0.4)
A (0.4)
A (0.4)
A (0.4)
A (0.4)
A (0.4)
8
6
18
10
7f
8
10–3
10–3
10–3
trace for some
9
11
15
10
3
35
40
33
3
3
3
~0
~0
~0
17
12
12
19
18
22
10
9
7
10
8
3
4
4
3
2
4
3
2
2
10
11
12
13
14
15
16
17
18
19
20
21
22
23
2×10–3
12
10–3
10–3
10–3
10–3
10–3
10–3
10–3
10–3
10–3
10–3
10–3
10–3
trace for some
10
10
6
38
38
34
4
4
3
~0
~0
~0
13
11
6
20
19
22
10
9
8
10
14
4
4
4
2
3
2
1
2
1
15
2
trace for some
19
28
40
40
40
41
41
31
24
31
30
32
29
29
4
4
4
4
4
4
5
~0
~0
~0
~0
~0
~0
~0
6
6
7
7
6
7
7
21
26
24
23
20
21
20
15
16
12
13
16
15
14
12
11
10
10
11
12
12
6
6
6
6
5
6
7
3
4
3
4
3
4
4
2
3
3
3
3
2
2
12
24
48
2
50
50
50
80
12
24
80
80
a The concentration of sodium sulfide, assuming sodium sulfide dissolved completely in MeCN.
b Catalysts: 15-crown-5 (A), PEG2000 (B), MPEG750 (C), PEG300 (D), tetraethylene glycol dimethyl ether (E).
c Total yields and ratios of 1–4, 5a, 6a, 7, and 8 were determined by integration of the 1H NMR spectra based on the amount of added catalyst;
yields of 5b and 6b were isolated. Compounds 2 and 3 were identified by 1H NMR, 13C NMR, and MS analysis of the mixture of 2 and 3.
d The cis-1,2-dichloroethylene reacted with sodium sulfide nonahydrate (see Tsuchiya et al.1).
e Isolated total yield in parentheses.
f Reaction of 1,1-dichloroethylene with Na2S and D2O in anhydrous MeCN.
Synthesis 2011, No. 15, 2454–2458 © Thieme Stuttgart · New York

2456
D.-Q. Sun, J.-K.Yang
PAPER
centration with N-methyl-2-pyrrolidone as solvent.9,10 the positive center of 1,1-dichloroethylene, which leads to
Accordingly, we attempted to synthesize unsaturated thi- the formation of sodium ethene-1,1-bis(thiolate) with
acrown ethers containing trans-carbon–carbon double fractional charge transfer through the double bond.11 One
bonds by treating trans-1,2-dichloroethylene with sodium of the NaS– anions dissociates from sodium ethene-1,1-
sulfide in low concentration in the presence of 15-crown- bis(thiolate) and recombines with another carbon atom
5 in acetonitrile, but discovered that, even at a temperature with the hydrogen anion transferring simultaneously. Al-
of 60 °C, the reaction only generated a small amount of ternatively, there is a possibility that the third NaS– anion
thioacetamide derived from the reaction of acetonitrile attacks the terminal carbon and initiates the expulsion of
with hydrogen sulfide, which was produced by the hydrol- one NaS– from the ethene-1,1-bis(thiolate) unit, which de-
ysis of sodium sulfide.
livers sodium ethene-1,2-bis(thiolate). In both cases, after
subsequent substitution reaction with the reactant, the fol-
lowing sulfur ions come from the syn-direction, resulting
in the formation of a series of cis-products. It is difficult
to produce ring compounds (six- to fifteen-membered
rings) containing trans-double bonds because of the high
strain force, but both kinds of double bonds (cis and trans)
could be furnished by attack of the sulfur ion in two dif-
ferent directions when the chain intermediate achieves a
certain length (usually containing six to seven sulfur
atoms). Moreover, the corresponding larger ring com-
pounds with trans-double bonds might also be generated
in small amounts in the reaction, but were difficult to iso-
late because of the very low yields. To probe the hydrogen
anion transfer mechanism, deuterium oxide and anhy-
drous Na2S were added to the reaction in anhydrous ace-
tonitrile instead of Na2S·9H2O. Under these conditions, no
deuterated thiacrown ether was detected, which suggests
the intramolecular hydrogen anion transfer theory oper-
ates.
NaS
Cl
Cl
H
H
SNa
SNa
Cl
SNa
SNa
H
H
H
SNa
H
SNa
NaS
SNa
H
H
SNa
SNa
H
SNa
SNa
H
NaS
SNa
NaS
S
DCE
NaS
1
In summary, an economical approach to the synthesis of
unsaturated thiacrown ethers, starting from 1,1-dichloro-
ethylene and sodium sulfide nonahydrate in the presence
of a phase-transfer catalyst has been developed. However,
the synthesis of specific large-membered unsaturated
thiacrown ethers in high yields and efforts to improve the
catalytic efficiency of the PEG series are still challenges
for us. Other heteroatomic unsaturated crown ethers may
also be obtained in the same way and will be the focus of
one of our further explorations.
NaS
NaS
SNa
SNa
H
NaS
S
S
NaS
DCE
NaS
2
H
NaS
S
NaS
DCE
NaS
All reactions were carried out under an atmosphere of nitrogen or
argon with magnetic stirring. Anhydrous MeCN was distilled from
CaH2 prior to use. Other reagents were used as obtained from com-
mercial sources unless otherwise noted. Analytical thin-layer chro-
matography was performed with commercial glass plates coated
with 0.20 mm silica gel 60 with 254 nm fluorescent indicator. Com-
pounds were visualized under ultraviolet light at 254 nm and by put-
ting the plate in an atmosphere of iodine. 1H and 13C NMR spectra
were recorded with a Bruker Avance 400 spectrometer or with a
Bruker Avance 300 spectrometer in CDCl3 at r.t. Chemical shifts
are reported in ppm (d) with TMS as internal standard. High resolu-
tion mass spectra were recorded with a Waters Micromass GCT
mass spectrometer. Melting points are uncorrected. IR data were re-
corded with a Thermo Nicolet AVATAR 360 FTIR spectrometer.
3, 4, 5a, 5b, 6a, 6b, 7, 8.....
b
SNa
S
SNa
a
S
S
S
S
S
S
S
S
S
+
S
S
S
S
S
S
S
S
S
S
6a (cis)
6b (trans)
Scheme 3 Plausible stepwise reaction mechanism
General Procedure: Method 1
A plausible mechanism is depicted in Scheme 3. The re-
action might occur in a stepwise way as described. When
a sodium ion is captured by either crown ether or PEG, the
NaS– anion can be actively liberated from the Na2S·9H2O
unit. Acting as nucleophile, two NaS– anions can attack
Ground Na2S·9H2O (7.35 g, 98%, 30 mmol) and 15-crown-5 (2.69
g, 98%, 12 mmol) were suspended in commercially available
MeCN (270 mL, AR, undried). A solution of 1,1-dichloroethylene
(4.94 g, 51 mmol) in MeCN (30 mL) was added dropwise to the sus-
pension with stirring over about 30 min. After additional stirring for
Synthesis 2011, No. 15, 2454–2458 © Thieme Stuttgart · New York

PAPER
An Economical Approach to the Synthesis of Unsaturated Thiacrown Ethers
2457
48 h at r.t., the reaction mixture was filtered, and the filtrate was
evaporated in vacuo and extracted with EtOAc (4 × 30 mL), washed
with H2O (2 × 15 mL) and dried over Na2SO4. After removal of sol-
vent, the residue was purified by chromatography on a silica gel col-
umn (300–400; petroleum ether–EtOAc, 3:1) to give the products
(33% total yield). Rf = 0.9 (1), 0.82 (2), 0.53 (4), 0.30 (5b), 0.27
(5a), 0.21 (6b), 0.13 (6a), 0.06 (7), 0.04 (8). The ratio of yields was
39:4:6:2:21:2:13:8:5.
IR (KBr): 3011, 1546, 1525, 1282, 1053, 821, 810, 720, 665, 640
cm–1.
1H NMR (400 MHz, CDCl3): d = 6.40 (s, 12 H).
13C NMR (100 MHz, CDCl3): d = 125.4.
MS (EI): m/z (%) = 348 (12) [M]+, 116 (100), 103 (78), 97 (18), 71
(47), 58 (22), 45 (40).
(E,Z,Z,Z,Z,Z)-1,4,7,10,13,16-Hexathiacyclooctadeca-
2,5,8,11,14,17-hexaene (5b)
Colorless solid; mp 129–131 °C.
1H NMR (400 MHz, CDCl3): d = 6.29 (d, J = 8.4 Hz, 2 H), 6.30 (s,
2 H), 6.35 (d, J = 8.0 Hz, 2 H), 6.42 (s, 2 H), 6.43 (d, J = 8.4 Hz,
2 H), 6.51 (d, J = 8.0 Hz, 2 H).
13C NMR (100 MHz, CDCl3): d = 120.3, 121.5, 122.4, 124.5, 129.7,
131.1.
MS (EI): m/z (%) = 348 (10) [M]+, 116 (100), 103 (32), 71 (20), 58
(8).
General Procedure: Method 2
Ground Na2S (2.6 g, 90%, 30 mmol), 15-crown-5 (2.69 g, 98%, 12
mmol) and D2O (5.4 g, 270 mmol) were suspended in anhydrous
MeCN (270 mL). A solution of 1,1-dichloroethylene (4.94 g, 51
mmol) in anhydrous MeCN (30 mL) was added dropwise to the sus-
pension with stirring over about 30 min. After additional stirring for
72 h at r.t., the reaction mixture was filtered, and the filtrate was
evaporated in vacuo and extracted with EtOAc (4 × 30 mL), washed
with D2O (2 × 15 mL) and dried over Na2SO4. The products were
purified as described in Method 1.
General Procedure: Method 3
(Z,Z,Z,Z,Z,Z,Z)-1,4,7,10,13,16,19-Heptathiacycloheneicosa-
2,5,8,11,14,17,20-heptaene (21-UT-7) (6a)
Colorless solid; mp 192–194 °C.
IR (KBr): 3026, 1557, 1539, 1277, 810, 716, 672, 636, 536 cm–1.
1H NMR (400 MHz, CDCl3): d = 6.33 (s, 14 H).
13C NMR (100 MHz, CDCl3): d = 123.7.
MS (EI): m/z (%) = 406 (4) [M]+, 116 (100), 103 (25), 71 (26).
Ground Na2S·9H2O (7.35 g, 98%, 30 mmol) and 15-crown-5 (2.69
g, 98%, 12 mmol) were suspended in commercially available
MeCN (300 mL, AR, undried). 1,1-Dichloroethylene (4.94 g, 51
mmol) was injected quickly into the suspension with stirring. After
additional stirring for 2 h at 80 °C, the reaction mixture was pro-
cessed as described in Method 1.
The characterization data for all known compounds match the data
given in Kamigata’s article.1
(E,Z,Z,Z,Z,Z,Z)-1,4,7,10,13,16,19-Heptathiacycloheneicosa-
2,5,8,11,14,17,20-heptaene (6b)
Colorless solid; mp 110–112 °C.
IR (KBr): 3015, 1541, 1281, 913, 800 cm–1.
1H NMR (400 MHz, CDCl3): d = 6.30 (d, J = 8.4 Hz, 2 H), 6.31 (d,
J = 8.4 Hz, 2 H), 6.32 (s, 2 H), 6.33 (d, J = 8.0 Hz, 2 H), 6.37 (d,
J = 8.40 Hz, 2 H), 6.38 (d, J = 8.4 Hz, 2 H), 6.50 (d, J = 8.0 Hz,
2 H).
13C NMR (100 MHz, CDCl3): d = 120.2, 121.5, 121.6, 122.3, 125.0,
128.1, 129.9.
1,4-Dithiin (1)
Light-yellow oil.
1H NMR (400 MHz, CDCl3): d = 6.21 (s, 4 H).
MS (EI): m/z (%) = 116 (100) [M]+, 71 (15), 58 (11).
(Z,Z,Z)-1,4,7-Propathiacyclopropadeca-2,5,8-propaene
(9-UT-3) (2)
Colorless solid
1H NMR (400 MHz, CDCl3): d = 6.27 (s, 8 H).
13C NMR (100 MHz, CDCl3): d = 123.8.
MS (EI): m/z = 174 [M]+.
MS (EI): m/z (%) = 406 (6) [M]+, 116 (100), 103 (38), 71 (24), 58
(8).
HRMS (EI): m/z [M]+ calcd for C14H14S7: 405.9141; found:
405.9144.
(Z,Z,Z,Z)-1,4,7,10-Butathiacyclobutadeca-2,5,8,11-butaene
(12-UT-4) (3)
Colorless solid
(Z,Z,Z,Z,Z,Z,Z,Z)-1,4,7,10,13,16,19,22-Octathiacyclotetracosa-
2,5,8,11,14,17,20,23-octaene (24-UT-8) (7)
Colorless crystals; mp 188–189 °C.
IR (KBr): 3026, 1558, 1272, 807, 725, 657, 624 cm–1.
1H NMR (400 MHz, CDCl3): d = 6.31 (s, 16 H).
MS (EI): m/z (%) = 464 (2) [M]+, 116 (100).
1H NMR (400 MHz, CDCl3): d = 6.43 (s, 8 H).
13C NMR (100 MHz, CDCl3): d = 126.1.
MS (EI): m/z = 232 [M]+.
(Z,Z,Z,Z,Z)-1,4,7,10,13-Pentathiacyclopentadeca-2,5,8,11,14-
pentaene (15-UT-5) (4)
Colorless crystals; mp 125–127 °C.
(Z,Z,Z,Z,Z,Z,Z,Z,Z)-1,4,7,10,13,16,19,22,25-Nonathiacyclohep-
tacosa-2,5,8,11,14,17,20,23,26-nonaene (27-UT-9) (8)
Colorless solid; mp 199–201 °C.
IR (KBr): 3024, 3009, 2998, 1556, 1524, 1292, 1282, 853, 809, 706,
679, 658, 649 cm–1.
1H NMR (400 MHz, CDCl3): d = 6.47 (s, 10 H).
13C NMR (100 MHz, CDCl3): d = 126.9.
MS (EI): m/z (%) = 290 [M]+ (12), 116 (100), 103 (65), 97 (16), 71
IR (KBr): 3034, 1604, 1562, 1271, 870, 719, 656, 624 cm–1.
1H NMR (400 MHz, CDCl3): d = 6.29 (s, 18 H).
MS (EI): m/z (%) = 522 (2) [M]+, 116 (100), 103 (20), 71 (32), 58
(12).
(28), 58 (25).
(Z,Z,Z,Z,Z,Z)-1,4,7,10,13,16-Hexathiacyclooctadeca-
2,5,8,11,14,17-hexaene (18-UT-6) (5a)
Colorless solid; mp 162–164 °C.
Supporting Information for this article is available online at
http://www.thieme-connect.com/ejournals/toc/synthesis.
Synthesis 2011, No. 15, 2454–2458 © Thieme Stuttgart · New York

2458
D.-Q. Sun, J.-K.Yang
PAPER
(6) (a) Shimizu, T.; Kawaguchi, M.; Tsuchiya, T.; Hirabayashi,
K.; Kamigata, N. Org. Lett. 2003, 5, 1443. (b) Shimizu, T.;
Kawaguchi, M.; Tsuchiya, T.; Hirabayashi, K.; Kamigata,
N. J. Org. Chem. 2005, 70, 5036.
Acknowledgment
We are grateful to the National Natural Science Foundation of Chi-
na, SRF for ROCS, SEM for financial support. We also thank Prof.
Yu-Liang Li, Mr. Li-Qiang Liu and Gang Lu for their kind help.
(7) (a) Shimizu, T.; Iwata, K.; Kamigata, N.; Ikuta, S. J. Chem.
Res., Synop. 1997, 38. (b) Shimizu, T.; Murakami, H.;
Kobayashi, Y.; Iwata, K.; Kamigata, N. J. Org. Chem. 1998,
63, 8192. (c) Shimizu, T.; Murakami, H.; Kamigata, N.
J. Org. Chem. 1999, 64, 8489. (d)Nakayama, J.; Takahashi,
K.; Watanabe, T.; Sugihara, Y.; Ishii, A. Tetrahedron Lett.
2000, 41, 8349. (e) Staeb, T. H.; Gleiter, R.; Rominger, F.
Eur. J. Org. Chem. 2002, 2815. (f) Ono, Y.; Sugihara, Y.;
Ishii, A.; Nakayama, J. J. Am. Chem. Soc. 2003, 125, 12114.
(g) Behbehani, H.; Ibrahim, Y. A.; Malhas, R. N. Kuwait J.
Sci. Eng. 2004, 31, 61. (h) Bauerle, P.;Ammann, M.; Wilde,
M.; Gotz, G.; Osteritz, E. M.; Rang, A.; Schalley, C. A.
Angew. Chem. Int. Ed. 2007, 46, 363. (i) Vujasinović, I.;
Veljković, J.; Molcanov, K.; Kojić-Prodić, B.; Mlinari-
Majerski, K. J. Org. Chem. 2008, 73, 9221. (j) Petrov, M.;
Shchipalkin, A.; Kuznetsov, V. Russ. J. Org. Chem. 2008,
44, 1089.
References
(1) Tsuchiya, T.; Shimizu, T.; Kamigata, N. J. Am. Chem. Soc.
2001, 123, 11534.
(2) (a) Tsuchiya, T.; Shimizu, T.; Hirabayashi, K.; Kamigata, N.
J. Org. Chem. 2002, 67, 6632. (b) Tsuchiya, T.; Shimizu,
T.; Hirabayashi, K.; Kamigata, N. J. Org. Chem. 2003, 68,
3480.
(3) (a) Tsuchiya, T.; Kurihara, H.; Sato, K.; Wakahara, T.;
Akasaka, T.; Shimizu, T.; Kamigata, N.; Mizorogi, N.;
Nagase, S. Chem. Commun. 2006, 3585. (b) Tsuchiya, T.;
Akasaka, T.; Nagase, S. Bull. Chem. Soc. Jpn. 2009, 82,
171. (c) Tsuchiya, T.; Akasaka, T.; Ohkubo, K.; Fukuzumi,
S.; Kato, T.; Nagase, S. ECS Meeting Abstracts 2009, 902,
2857. (d) Taherpour, A. Fullerenes, Nanotubes, Carbon
Nanostruct. 2007, 15, 405. (e) Taherpour, A. Fullerenes,
Nanotubes, Carbon Nanostruct. 2008, 16, 142.
(f) Taherpour, A. Fullerenes, Nanotubes, Carbon
Nanostruct. 2009, 17, 171. (g) Taherpour, A. Phosphorus,
Sulfur Silicon Relat. Elem. 2010, 185, 422.
(8) (a) Schroth, W.; Moegel, L. Z. Chem. 1981, 21, 30.
(b) Cabianca, E.; Tatibouët, A.; Fabris, F.; De Lucchi, O.;
Rollin, P. Tetrahedron Lett. 2005, 46, 1035.
(9) Ikeda, Y.; Ozaki, M.; Arakawa, T. J. Chem. Soc., Chem.
Commun. 1983, 1518.
(10) Ikeda, Y.; Nagoya, I.; Ozaki, M. Synth. Met. 1987, 21, 235.
(11) Glaser, R.; Choy, G. S.-C.; Chen, G. S.; Grützmacher, H.
J. Am. Chem. Soc. 1996, 118, 11617.
(4) Tsuchiya, T.; Okada, Y.; Shimizu, T.; Hirabayashi, K.;
Kamigata, N. J. Org. Chem. 2008, 73, 76.
(5) Nakayama, J.; Kaneko, A.; Sugihara, Y.; Ishii, A.
Tetrahedron 1999, 55, 10057.
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