An in depth study of the formation of new tetrathiafulvalene derivatives from 1,8-diketones

Article abstract of DOI:10.1016/j.tet.2003.08.042

A detailed study of the reactions of phosphorus pentasulfide and Lawesson's reagent with a series of 4,5-bis(RCOCH ₂S)-1,3-dithiole-2-thiones (R=Ph, 4-MeOC₆H₄, 4-Br C₆H₄, Me) has been carried out. These reactions lead to fusion of either an unsaturated 1,4-dithiin ring or a thiophene to the dithiole; the former in higher yield, while the latter is a significant product in the reactions with Lawesson's reagent; as well as small amounts of minor products. A mechanistic rationalization of these products is discussed in some detail. The new fused dithioles have been converted to novel series of fused TTF derivatives.

Full text of DOI:10.1016/j.tet.2003.08.042

Tetrahedron 59 (2003) 8107–8116
An in depth study of the formation of new tetrathiafulvalene
derivatives from 1,8-diketones
Figen Turksoy,a John D. Wallis,b Umit Tuncaa and Turan Ozturkc
,
*
aDepartment of Chemistry, Art and Science Faculty, Istanbul Technical University, Maslak, Istanbul, Turkey
bDepartment of Chemistry, The Nottingham Trent University, Clifton Lane, Nottingham NG11 8NS, UK
cDepartment of Chemistry, Organic Chemistry, Middle East Technical University, Ankara, Turkey
Received 1 May 2003; revised 28 July 2003; accepted 22 August 2003
Abstract—A detailed study of the reactions of phosphorus pentasulfide and Lawesson’s reagent with a series of 4,5-bis(RCOCH2S)-1,3-
dithiole-2-thiones (R¼Ph, 4-MeOC6H4, 4-Br C6H4, Me) has been carried out. These reactions lead to fusion of either an unsaturated
1,4-dithiin ring or a thiophene to the dithiole; the former in higher yield, while the latter is a significant product in the reactions with
Lawesson’s reagent; as well as small amounts of minor products. A mechanistic rationalization of these products is discussed in some detail.
The new fused dithioles have been converted to novel series of fused TTF derivatives.
q 2003 Elsevier Ltd. All rights reserved.
1. Introduction
There has been continued interest in the synthesis of
derivatives of tetrathiafulvalene, TTF 1. This is due to the
metallic behaviour of its radical cation salts with mono
anions and charge transfer complexes with electron
acceptors such as TCNQ, which exhibit semi-conducting,
conducting and superconducting properties. It has been
established that the physical properties of the radical cation
salts depend on the electronic and structural features of TTF
derivatives.1 The most widely studied derivative, bis(ethyl-
enedithio)tetrathiafulvalene (BEDT-TTF or ET) 2, has
yielded some salts which show superconducting properties,
including k-(BEDT-TTF)Cu[N(CN)2Br] which has the
highest critical temperature, Tc¼12.8 K, for an organic
superconductor.2 In recent years, the electron-donating
property of TTF has led to the synthesis of various
analogues with different potential applications such as
chromophores for dyes, nonlinear optics, synthetic light-
harvesting systems, liquid crystals,3 dendrimers,4–6 phthalo-
cyanines,4,5 polymers,7 and supramolecular switches.8
Obviously, such a wide range of application possibilities
requires the synthesis of TTF derivatives bearing versatile
aimed at (i) extension of the conjugation of the molecule to
functional groups.
To improve the conducting properties, efforts have been
delocalize the charges formed in the charge transfer salts
and (ii) introduction of hydrogen bonding groups to produce
specific attractive interactions with the anions in the derived
radical cation salts.1b So far, extension of conjugation has
been achieved in the centre of the molecule,1b but, there are
just a few examples of the introduction of conjugation at the
peripheral ethylene bridges,9 and they are achieved with
conventional methods which have limited applications.
Keywords: 1,8-diketone ring formation; 1,4-dithiin; thiophene; BEDT-
TTF; TTF.
*
Corresponding author. Tel.: þ90-3122105103; fax: þ90-3122105104;
e-mail: trozturk@yahoo.com
0040–4020/$ - see front matter q 2003 Elsevier Ltd. All rights reserved.
doi:10.1016/j.tet.2003.08.042

8108
F. Turksoy et al. / Tetrahedron 59 (2003) 8107–8116
Recently, we have reported a convenient method of
synthesizing fused 1,4-dithiin ring systems with various
functional groups (3, 4).10 This method has allowed
conjugation to be introduced into the peripheral ethylene
bridges of the BEDT-TTF system. As far as we are aware
this is the best method available to synthesize molecules
with substituted 1,4-dithiin rings fused to tetrathiafulval-
ene,11 and it has potential to find convenient applications
with other ring systems to generate various fused 1,4-dithiin
heterocycles.10a Installation of functional groups such as
4-CH3OC6H4 and 4-BrC6H4 to the periphery of a fully
conjugated BEDT-TTF will provide easy access to the
construction of more complex systems.
2. Results and discussion
2.1. Synthesis of fused 1,4-dithiins and thiophenes;
1,8-diketone ring formation reaction
Scheme 1. (a) THF (dry), N2, rt, overnight; (b) LR or P4S10, toluene, reflux
overnight (LR), 3 h (P4S10).
Scheme 2. LR, toluene, reflux, overnight.
undergoes in situ cyclization to give thiophene 17 (Scheme
2). Although the 1,8-diketone ring closure reaction to form
1,4-dithiin and thiophene is an unusual reaction of LR and
P4S10 we suggest that initial reaction of 1,8-diketones, as in
the case of 1,4-diketones, is the formation of 1,8-dithione 18
intermediates, which is very likely to be in equilibrium with
its corresponding dienedithol 19 and can form the nine-
membered ring 20. This highly unstable ring then rearranges
to a six-membered ring as a zwitterion 21 (Scheme 3).
The side products 12–14 isolated from the cyclization
reactions provide further evidence to our prediction. On the
other hand, one may claim that an attack from one of the
exocyclic sulfur atoms to the thiocarbonyl carbon may result
in the same products, although it can be understood easily
that such an attack is very difficult since the exocyclic sulfur
atoms are so hindered and in conjugation with a double
bond. The possibility of such a nucleophilic attack was
investigated, using computational chemistry, from the
hindered exocyclic sulfur atoms to the thiocarbonyl carbons,
that is from S1 to C5 or from S7 to C3 of 18 (Scheme 3). The
conformational analysis of 18 with the MMFF method
showed that the distances between S1–C5 and S7–C3 are
too long that such a nucleophilic attack is not possible. On
the other hand, the analysis indicated that 1,8-dithione 18 is
in equilibrium with its corresponding dienedithiol form 19,
and the dithiol forms were found to be more stable than the
dithione forms. This means the tautomeric equilibrium
favours the dithiol form 19. We predict that the elimination
of H2S from the dithiol 19 gives the nine-membered ring 20.
Cyclization of 1,8-diketones 8, obtained from the reaction of
readily available dithiolate 612 with a-haloketones 7, is the
crucial step of this study. The 1,8-diketones were prepared
in dry THF or EtOH at room temperature under nitrogen
atmosphere, and were then subjected to the 1,8-diketone
ring formation reaction10 using either Lawesson’s reagent
(LR) 5 or P4S10 in refluxing dry toluene under nitrogen
atmosphere, until the consumption of the starting material
was complete (Scheme 1). With both LR and P4S10, the
reaction resulted in the formation of a fused six-membered
1,4-dithiin ring 9 and a fused five-membered thiophene ring
10 along with various side products 11–14. The thiophenes
10 are probably derived from 9 by loss of a sulfur atom.
It is well established that both LR and P4S10 are useful
reagents for both conversion of ketones to thiones13 and
formation of thiophenes 17 from 1,4-diketones 15.14 Even
in the latter case, the initial reaction is conversion of a
1,4-diketone to a 1,4-dithione 16, which subsequently

F. Turksoy et al. / Tetrahedron 59 (2003) 8107–8116
8109
Scheme 3. Proposed mechanism for the formation of nine-membered ring
and its rearrangement to six-membered ring.
The molecular modelling studies of 20 indicated that the
˚
distances from S1 to C5 and from S7 to C3 are both 3.46 A.
This makes the rearrangement possible by attacking from
the sulfurs S1/S7 to the corresponding carbons C5/C3 to
produce the zwitterion 21. The semiempirical PM3
calculations predicted that the activation energy for such
an attack is 35.526 kcal/mol, including zero point energy
correction, which can be overcome easily under the reflux
conditions in toluene. As expected, formation of the
zwitterionic intermediate 21 is an endothermic reaction
with DHrxn¼29.435 kcal/mol. Following Hammond’s
postulate, therefore, the predicted structure of the transition
state resembles that of the intermediate 21. A detailed study
of semiempirical calculations is in preparation and will be
published elsewhere.
Scheme 5. Proposed mechanism for thiophene side products.
cyclic reaction with the decomposition product 22 of LR,
which is the actual reagent for replacing oxo groups with
thioxo groups rather than undecomposed LR 5 itself,15
to free the fused 1,4-dithiin molecule 9 and give the
2-phospha-1,3-dithiole-2-thione 23 (Scheme 4). Unfortun-
ately, we have never isolated any product such as 23 to
prove this mechanism. On the other hand, our latest results
have indicated that other mechanisms for decomposition of
the zwitterion are in operation, which can explain the
generation of the side products. The zwitterion 21 reacts
with a second zwitterion following two different mechan-
isms (Scheme 5). In one case, the two enethiolate side
chains (which could in principle react as nucleophiles
through S or the b-carbon) react together forming two C,S
bonds to give a 1,4-dithiin which can lose sulfur to give
2,4-disubstituted thiophene 13, while in the second case the
two b-carbons bond and one thiolate S attacks the a-carbon
of the other side chain forming a thiiranothiophene which
loses sulfur to give 2,5-thiophenes 12 and 14. Unfortunately,
in the other case, where R¼CH3, such side products could
not be isolated.
Our initial assumption10a was that the zwitterion 21 gave a
Moreover in one reaction (R¼Ph), an interesting by-
product, 3,6-diphenylthieno[2,3-b][1,4]dithiin 11, was iso-
lated and its structure was established by X-ray diffraction
analysis (Fig. 1). A possible explanation for the mechanism
Scheme 4. 1,4-Dithiin formation.

8110
F. Turksoy et al. / Tetrahedron 59 (2003) 8107–8116
Scheme 7. Formation of thiophene from dithiin.
It appears that carrying out the 1,8-diketone ring formation
reaction with P4S10 improves the yield of the major product,
1,4-dithiin (Table 1). On the other hand, reaction with LR
improves the yield of the thiophene product, though it
remains the minor product. It appears that the reaction time
is an important factor here, since both reagents follow a
similar mechanism.15 Our results indicate that the reactions
with P4S10 are complete in ca. 3 h while the reactions with
LR require overnight reflux, which means a longer reaction
time causes the 1,4-dithiin ring to lose a sulfur atom to
form the thiophene (Scheme 7). When the reaction of
1,8-diketone, where R¼CH3, was carried out with LR, little
formation of 1,4-dithiin, 5%, was observed. However, when
the reaction was conducted with P4S10, a much higher yield
of 1,4-dithiin was isolated, 52%.
Figure 1. X-Ray diffraction analysis of 11.
is that the zwitterion 21 decomposes by the enethiolate
fragment bonding to the double bond at the fusion of the
ring system (Scheme 6). The resultant tetra-cyclic inter-
mediate 25 then rearranges to give the bicyclic product 11
with loss of carbon disulfide and sulfur. Surprisingly, such a
product could only be isolated where the side groups were
phenyl.
2.3. Coupling reactions
Couplings of the 1,4-dithiins 9a-d and the thiophenes 10a-c
to give new fused TTF derivatives were carried out
employing the well-established procedure in the literature.16
Initially, the thione sulfur atoms of all the dithiins and the
thiophenes were converted to oxygen with mercuric acetate
to obtain 27 and 28, respectively (Scheme 8).
Scheme 6. Proposed mechanism for thienodithiin side product.
2.2. Yields
Although the 1,8-diketone ring formation reaction with LR
and P4S10 gave 1,4-dithiin 9 as a main product in all cases, it
appears that the thiophene 10 is the second major product in
many cases, even though it could not be obtained at all in
some reactions such as with P4S10 where R¼Ph or CH3 and
with LR where R¼CH3 (Table 1). Their formation possibly
follows the rearrangement of the dithiin ring 9, which leads
to the formation of the tetracyclic intermediate 26, from
which loss of sulfur produces the fused thiophenes 10
(Scheme 7).
Scheme 8. (a) Hg(OAc)2, AcOH/CHCl3, rt, 1 h.
Oxo compound 27 was coupled with the readily available
4,5-di(methylsulfanyl)-1,3-dithiol-2-one 2917 in neat
triethyl phosphite at 1108C under a nitrogen atmosphere,
which yielded a mixture of four compounds (Scheme 9). A
successful column chromatography resulted in the separ-
ation of the cross-coupled organosulfur donor 30 (20–25%),
a cis and trans mixture of self-coupled material 31 and the
tetrasubsituted TTF 32. Couplings of the 1,4-dithiins 27
were also carried out with the unsubstituted bicyclic oxo
compound 33 (Scheme 9), employing the same reaction
conditions. Column chromatography of the reaction mixture
gave four compounds; cross-coupled organosulfur donor 34
Table 1. Yields form LR and P4S10 reactions
P4S10
LR
9 (%)
10 (%)
9 (%)
10 (%)
a
b
c
49
45
40
52
–
15
2
40
30
35
5
17
27
18
–
d
–

F. Turksoy et al. / Tetrahedron 59 (2003) 8107–8116
8111
the synthesis of 38 (20%) along with ET 2 and the isomeric
mixture of 36 and 37 (Scheme 11).
2.4. Cyclic voltammetry (CV) measurements
Oxidation potentials of the new organosulfur donors 30, 34
and 35 prepared in the coupling reactions, were measured by
cyclic voltammetry, and are compared with data for ET 2
(Tables 2 and 3). The CV measurements in Tables 2 and 3
were carried out in acetonitrile containing NaClO4 or
dichloromethane containing TBABF4, respectively. The CV
measurements of ET were also performed separately in
these two solutions. Placing a double bond at the bridgehead
of ET as in the series 34 leads to an increase in the two
oxidation potentials for these donors by ca. 0.15 V (for E1)
and by ca. 0.2 V (for E2). Apart from the extra conjugation
possible, the fully unsaturated six-membered ring is likely
to be flexed about the S–S axis, while in ET, this ring adopts
an envelope conformation in which just one carbon from the
ethylene bridge is out of plane. Compared with series 34,
replacing the remaining –CH2CH2– bridge by two methyl
groups as in series 30, leads to a significant reduction in the
oxidation potentials, so that they both lie just less than that
of ET itself. In these compounds the S–Me bonds are likely
to lie perpendicular to the best of plane of the donor
molecule, in contrast to ET. When a sulfur atom is removed
from the dithiin ring in this latter series to give series 35,
which have the fused thiophene instead, then the oxidation
potential rise again, typically by ca. 0.1 V for E1 and ca.
0.2 V for E2. Nevertheless, all these donors are candidates
for formation of radical cation salts and charge transfer salts.
Scheme 9. (a) (EtO)3P, N2, 3 h, 1108C.
Table 2. CV measurements of 30a-d in ca. 1 mM MeCN solutions, NaClO4
(0.1 M), vs Ag/AgCl, 100 mV s21
E11/2 (V)
E21/2 (V)
DE
30a
30b
30c
30d
ET
0.49
0.50
0.47
0.42
0.50
0.63
0.63
0.72
0.66
0.77
0.14
0.13
0.25
0.24
0.27
Scheme 10. (a) (EtO)3P, N2, 3 h, 1108C.
(15–20%), a cis and trans mixture of self-coupled 31, and
ET 2.
Cross-coupling products of fused thiophenes 28 were
obtained by performing the reaction with 4,5-di(methyl-
sulfanyl)-1,3-dithiol-2-one 29 in triethyl phosphite at 1108C
under nitrogen atmosphere, which produced a mixture
of four compounds (Scheme 10). A successful column
chromatography achieved their separation as the cross-
coupled TTF derivatives 35 (19–22%), a cis and trans
mixture of 36 and 37, respectively, and the tetrasubstituted
TTF 32.
Table 3. CV measurements of 34a-d and 35a-c in ca. 1 mM CH2Cl2
solutions, TBABF4 (0.1 M), vs Ag/AgCl, 115 mV s21
34a
34b
34c
34d
0.66
0.60
0.68
0.64
0.96
0.95
1.00
0.99
0.30
0.35
0.32
0.24
35a
35b
35c
0.59
0.51
0.62
0.86
0.83
0.94
0.27
0.32
0.32
Coupling of 28 was also carried out with the oxo compound
33 under the usual coupling conditions, which resulted in
ET
0.51
0.85
0.34
3. Conclusion
In this study, reaction mechanisms offormation of 1,4-dithiins
and thiophenes from the reactions of diketones with LR and
P4S10 have been investigated. Using this reaction as a tool,
various TTF analogues have been prepared and their CV
properties have been presented. It has been demonstrated
that 1,8-diketone ring formation reaction can be applied to
Scheme 11. (a) (EtO)3P, N2, 3 h, 1108C.

8112
F. Turksoy et al. / Tetrahedron 59 (2003) 8107–8116
the preparation of various dithiin and thiophene analogues,
which could be particularly important for material
chemistry.
4.1.4. 1-[5-(2-Oxopropylsulfanyl)-2-thioxo-1,3-dithiol-4-
ylsulfanyl]propan-2-one (8d). The crude product was
crystallized from ethanol to give the title compound 8d
(1.84 g, 72%) as an orange powder, mp 75–788C. [Found:
C, 34.90, H, 3.3. C9H10O2S5 requires C, 34.8, H, 3.22%];
n
max(Nujol) 1700 (CvO), 1060 (CvS) cm21; dH 3.78 (4H,
4. Experimental
4.1. General
s, SCH2CO), 2.30 (6H, s, CH3); dC 207.0 (CvS), 200.8
(CvO), 138.3, 46.3 (SCH2), 28.7 (SCH3); m/z (FAB,
NOBA matrix) 310 (Mþ).
Melting points are uncorrected. NMR spectra were recorded
in CDCl3 with tetramethylsilane as the internal standard for
1H (200 MHz) or solvent as the internal standard for 13C
(67.8 MHz) unless otherwise stated. Mass spectra were
recorded at an ionising voltage of 70 eV. Chromatography
was performed on flash silica gel (Merck) and TLC was
carried out on 0.2 mm silica gel plates. All reagents and
solvents were commercial grade (Aldrich) and purified
according to established convention.
4.1.5. 5-Phenyl[1,3]dithiolo[4,5-b][1,4]dithiin-2-thione
(9a). (a) A mixture of 8a (1.00 g, 2.30 mmol) and
Lawesson’s reagent 5 (1.10 g, 2.71 mmol) was boiled
under reflux in dry toluene (25 mL) under a N2 atmosphere
until the starting material was consumed. After 4 h, toluene
evaporated under reduced pressure and the residue was
separated by column chromatography, eluting with hexane/
CH2Cl2 (2/1) to give 11 (yellow powder, 0.11 g, 15%), 1320,21
(yellow powder, 49 mg, 9%), the title compound 9a (yellow
powder, 0.28 g, 40%) and 10a (light brown powder, 0.1 g,
17%) in order of elution.
4.1.1. 2-[5-(2-Oxo-2-phenylethylsulfanyl)-2-thioxo-1,3-
dithiol-4-ylsulfanyl]-1-phenylethanone (8a). To the solu-
tion of dianion 6 (2.00 g, 8.26 mmol) in dry THF (100 mL),
under a N2 atmosphere and in an ice bath, was added
2-bromoacetophenone 7a (3.29 g, 16 mmol) dissolved in
dry THF (80 mL) dropwise from a dropping funnel, and the
mixture was left stirring overnight at room temperature. The
solvent was then evaporated in vacuo and the residue was
extracted with dichloromethane (3£100 mL), dried over
Na2SO4, filtered and the solvent was evaporated in vacuo.
The crude product was recrystallized from ethanol to give
the title compound 8a (2.57 g, 72%) as an orange powder,
mp 89–928C. [Found: C, 52.55; H, 2.94. C19H14O2S5
requires C, 52.53, H, 3.22%]; nmax(Nujol) 1670 (CvO),
1050 (CvS) cm21; dH 7.92 (4H, d, J¼7.6 Hz, Ar), 7.50
(6H, m, Ar), 4.41 (4H, s, SCH2CO); dC 210.4, 192.3, 137.1,
134.9, 134.1, 128.9, 128.5, 43.1 (SCH2); m/z (FAB, NOBA
Matrix) 435 (Mþþ1); m/z (EI) 434 (Mþ).
(b) A mixture of 8a (0.50 g, 1.15 mmol) and phosphorus
pentasulfide (0.55 g, 1.23 mmol) was boiled under reflux in
dry toluene (20 mL) under a N2 atmosphere until the starting
material was consumed (1 h). The precipitate was filtered
off, and toluene was evaporated under reduced pressure. The
residue was separated by column chromatography eluting
with hexane/CH2Cl2 (2/1) to give 1218,19 (yellow powder,
22 mg, 8%) and the title compound 9a (yellow powder,
0.17 g, 49%) as first and second fractions, respectively.
Compound 9a. Mp 145–1488C. [Found: C, 44.14, H, 1.98.
C11H6S5 requires C, 44.29, H, 2.01%]; nmax(Nujol) 1080
(CvS) cm21; dH 7.54 (2H, m, Ar), 7.39 (3H, m, Ar), 6.66
(1H, s, vCH); dC 213.8 (CvS), 142.4, 134.9, 129.7, 129.3,
128.9, 128.7, 127.3, 117.6; m/z (FAB, NOBA Matrix) 298
(Mþ); m/z (EI) 298 (Mþ).
The following were similarly prepared.
4.1.6. 6-Phenylthieno[2,3-d][1,3]dithiole-2-thione (10a).
Mp 210–2128C. [Found: C, 49.34, H, 2.38. C11H6S4
requires C, 49.62, H, 2.25%]; dH 7.57 (2H, m, Ph), 7.44
(3H, m, Ar), 7.28 (1H, s, thiophene); dC 214.6 (CvS),
136.3, 129.2, 128.8, 128.6, 126.5, 125.7, 125.2, 115.5; m/z
(FAB, NOBA Matrix) 267 (Mþþ1).
4.1.2. 1-(4-Methoxyphenyl)-2-{5-[2-(4-methoxyphenyl)-
2-oxoethylsulfanyl]-2-thioxo-1,3-dithiol-4-ylsulfanyl}
ethanone (8b). The crude product was crystallized from
ethanol to give the title compound 8b (2.85 g, 70%) as
orange needles, mp 98–1008C. [Found: C, 51.27, H, 3.44.
C21H18O4S5 requires C, 51.01; H, 3.64%]; nmax(Nujol) 1660
(CvO), 1080 (CvS) cm21; dH 7.90 (4H, d, J¼8.8 Hz, Ph),
6.90 (4H, d, J¼8.8 Hz, Ph), 4.31 (4H, s, SCH2CO), 3.87
(6H, s, OCH3); dC 210.8 (CvS), 190.8 (CvO), 164.2,
137.2, 130.9, 127.9, 114.1, 55.6 (OCH3), 42.9 (SCH2); m/z
(EI) 494 (Mþ).
4.1.7. 3,6-Diphenylthieno[2,3-b][1,4]dithiin (11). Mp
117–1198C. [Found: C, 66.39, H, 3.36. C18H12S3 requires
C, 66.60, H, 3.70%]; dH 7.52 (4H, m, Ar), 7.35 (6H, m), 7.01
(1H, s, thiophene), 6.65 (1H, s, dithiin); dC 138.0, 136.0,
133.0, 131.0, 128.9, 128.8, 128.6, 128.0, 127.7, 126.8,
125.7, 125.5, 121.0, 118.0; m/z (EI) 324 (Mþ); m/z (LSI)
324 (Mþ), 290 (Mþ2H2S), 247 (Mþ2Ph), 203
(Mþ2PhCS).
4.1.3. 1-(4-Bromophenyl)-2-{5-[2-(4-bromophenyl)-2-
oxoethylsulfanyl]-2-thioxo-1,3-dithiol-4-ylsulfanyl}
ethanone (8c). The crude product was crystallized from
ethanol to give the title compound 8c (3.08 g, 63%) as an
orange powder, mp 140–1438C. [Found: C, 52.91, H, 2.63.
C19H12Br2O2S5 requires C, 52.7, H, 2.77%]; nmax(Nujol)
1680 (CvO), 1060 (CvS) cm21; dH (DMSO) 7.90 (4H, d,
J¼8.5 Hz, Ar), 7.75 (4H, d, J¼8.5 Hz, Ar), 4.69 (4H, s,
SCH2CO); dC (DMSO) 210.7 (CvS), 192.6 (CvO), 144.0,
133.7, 131.7, 130.4, 127.9, 42.7; m/z (FAB, NOBA matrix)
592 (Mþ).
The following were similarly produced.
4.1.8. 5-(4-Methoxyphenyl)[1,3]dithiolo[4,5-b]
[1,4]dithiin-2-thione (9b). The residue was separated by
column chromatography eluting with hexane/CH2Cl2 (2/
1) to give the title compound 9b as a first fraction (yellow
powder, 0.2 g, 30% with LR and 0.3 g, 45% with P4S10) and
10b10a,d as a second fraction (0.16 g, 27% with LR and

F. Turksoy et al. / Tetrahedron 59 (2003) 8107–8116
8113
0.09 g, 15% with P4S10). 9b Mp 88–908C. [Found: C, 44.16,
The following were similarly produced.
H, 2.51. C12H8OS5 requires C, 43.90, H, 2.43%]; dH
(270 MHz) 7.42 (2H, d, J¼9.0 Hz, Ar), 6.90 (2H, d,
J¼9.0 Hz, Ar), 6.65 (1H, s, vCH), 3.82 (3H, s, OCH3);
dC 213.9 (CvS), 160.8, 142.6, 129.1, 128.8, 127.3, 115.0,
114.3, 55.4 (OCH3); m/z (FAB, NOBA matrix) 328 (Mþ).
4.1.14. 5-(4-Methoxyphenyl)[1,3]dithiolo[4,5-b]
[1,4]dithiin-2-one (27b). White powder (0.42 g, 90%), mp
146–1488C. [Found: C, 46.51, H, 2.65. C12H8O2S4 requires
C, 46.15, H, 2.56%]; nmax(Nujol) 1670 (CvO) cm21; dH
(270 MHz) 7.50 (2H, d, J¼9.0 Hz, Ar), 6.90 (2H, d,
J¼9.0 Hz, Ar), 6.50 (1H, s, vCH), 3.83 (3H, s, OCH3);
dC 192.0 (CvO), 160.7, 142.3, 128.9, 127.6, 119.4, 114.5,
114.2, 114, 55.4; m/z (EI) 312 (Mþ).
4.1.9. 5-(4-Bromophenyl)[1,3]dithiolo[4,5-b][1,4]dithiin-
2-thione (9c). The residue was separated by column
chromatography eluting with hexane/CH2Cl2 (2/1) to give
14 (yellow powder, 6.6 mg,10% with P4S10), the title
compound 9c (yellow powder, 0.22 g, 35% with LR and
0.26 g, 40% with P4S10) and 10c (light brown powder,
0.1 g, 18% with LR and 12 mg, 2% with P4S10) in order
of elution.
4.1.15. 5-(4-Bromophenyl)[1,3]dithiolo[4,5-b][1,4]
dithiin-2-one (27c). White powder (0.40 g, 85%), mp
135–1378C. [Found: C, 36.71; H, 1.23. C11H5BrOS4
requires C, 36.56, H, 1.38%];
nmax(Nujol) 1660
(CvO) cm21; dH 7.50 (2H, d, J¼8.7 Hz, Ar), 7.40 (2H, d,
Compound 9c. Mp 150–1528C. [Found: C, 35.24; H, 1.56.
C11H5BrS5 requires C, 35.0, H, 1.32%]; nmax(KBr) 1059
(CvS) cm21; dH (270 MHz) 7.52 (2H, d, J¼8.8 Hz, Ar),
7.41 (2H, d, J¼8.8 Hz, Ar), 6.68 (1H, s, vCH); dC 214.6
(CvS), 141.2, 133.9, 132.1, 129.3, 128.8, 124.1, 118.4; m/z
(EI) 377 (Mþ).
J¼8.7 Hz, Ar), 6.60 (1H, s, vCH); m/z (EI) 361 (Mþ).
4.1.16. 5-Methyl[1,3]dithiolo[4,5-b][1,4]dithiin-2-one
(27d). White powder (0.41 g, 93%), mp 73–768C. [Found:
C, 32.60; H, 1.63. C6H4OS4 requires C, 32.72, H, 1.81%];
dH 6.17 (1H, s, vCH), 2.20 (3H, s, CH3); dC 195.0 (CvO),
137.7 (qC), 119.0 (qC), 116.7 (CH), 107.0 (qC), 22.2 (CH3);
m/z (EI) 220 (Mþ).
4.1.10. 6-(4-Bromophenyl)thieno[2,3-d][1,3]dithiole-2-
thione (10c). Mp 120–1238C. [Found: C, 38.62; H, 1.36.
C11H5BrS4 requires C, 38.26, H, 1.45%]; nmax(KBr) 1050
(CvS) cm21; dH (270 MHz) 7.58 (2H, d, J¼8.6 Hz, Ar),
7.42 (2H, d, J¼8.6 Hz, Ar), 7.28 (1H, s, vCH); dC 213.7
(CvS), 148.6, 139.2, 132.4, 131.7, 132.4, 128.1, 127.1,
115.9; m/z (EI) 345 (Mþ).
4.1.17. 6-Phenylthieno[2,3-d][1,3]dithiol-2-one (28a). A
mixture of 10a (0.20 g, 0.75 mmol) dissolved in CHCl3
(20 mL), mercuric acetate (0.60 g, 1.9 mmol) and glacial
acetic acid (6.25 mL) was stirred at room temperature for
1 h. The mixture was filtered through celite and the filtrate
was extracted with sodium carbonate solution (2£50 mL)
and water (2£50 mL). The organic layer was dried over
sodium sulphate, filtered and the solvent was evaporated
under reduced pressure to give the title compound 28a
(0.13 g, 70%) as a white powder, mp 113–1158C. [Found:
C, 52.51, H, 2.78. C11H6O2S3 requires C, 52.59, H, 2.79%];
dH (270 MHz) 7.52 (2H, m, Ar), 7.38 (3H, m, Ar), 7.34 (1H,
s, vCH); dC 193.4 (CvO), 146.1 (qC), 129.8 (qC), 128.6
(CH), 127.8 (CH), 126.8 (CH), 116.9 (CH); m/z (EI) 251
(Mþ).
4.1.11. 2,5-Di(bromophenyl)thiophene (14). Mp 155–
1578C. [Found: C, 48.55, H, 2.32. C16H10Br2S requires C,
48.73, H, 2.53%]; dH 7.49 (8H, 2£d, J¼10.2, 9.1 Hz, Ar),
7.25 (2H, s, thiophene); dC 143 (qC) 133 (qC) 132 (CH), 127
(CH), 125 (CH), 122 (qC). HRMS (EI): Mþ, found
393.8852. C16H10Br2S requires 393.8849.
The following was similarly produced.
4.1.12. 5-Methyl[1,3]dithiolo[4,5-b][1,4]dithiin-2-thione
(9d). Orange powder, 0.40 g, 52% with LR and 38 mg,
5% with P4S10, mp 100–1028C. [Found: C, 30.62, H, 1.40.
C6H4S5 requires C, 30.50, H, 1.69%]; nmax(Nujol) 1061
(CvS) cm21; dH 6.19 (1H, s, vCH), 2.19 (3H, s, CH3); dC
213.8 (CvS), 138 (qC), 128.4 (qC), 116.8 (CH), 22.3
(CH3); m/z (FAB, NOBA matrix) 236 (Mþ).
The following were similarly produced.
4.1.18. 6-(4-Methoxyphenyl)thieno[2,3-d][1,3]dithiol-2-
one (28b). White powder, 70 mg, 35%, mp 185–1878C.
[Found: C, 48.50, H, 2.75. C11H5BrOS3 requires C, 48.64,
H, 2.70%]; dH (270 MHz) 7.54 (2H, d, J¼9.0 Hz, Ar), 7.14
(1H, s, vCH), 6.91 (2H, d, J¼9.0 Hz, Ar), 3.84 (3H, s,
OCH3); dC 194.6 (CvO), 159.2 (qC), 142.7 (qC), 127.2
(qC), 126.8 (CH), 122.9 (CH), 114.7 (CH), 55.4 (OCH3);
m/z (EI) 296 (Mþ).
4.1.13. 5-Phenyl[1,3]dithiolo[4,5-b][1,4]dithiin-2-one
(27a). A mixture of 9a (0.50 g, 1.67 mmol) dissolved in
CHCl3 (20 mL), mercuric acetate (1.33 g, 4.18 mmol) and
glacial acetic acid (10 mL) was stirred at room temperature
for 1 h. The mixture was filtered through celite and the
filtrate was extracted with sodium carbonate solution
(2£50 mL) and water (2£50 mL). The organic layer was
dried over sodium sulphate, filtered and the solvent was
evaporated under reduced pressure to give the title
compound 27a (0.37 g, 90%) as a white powder, mp 105–
1088C. [Found: C, 46.51, H, 1.98. C11H6OS4 requires C,
46.80, H, 2.12%]; nmax(Nujol) 1665 (CvO) cm21; dH
(270 MHz) 7.55 (2H, m, Ar), 7.38 (3b H, m, Ar), 6.64 (1H,
s, vCH); dC 191.9 (CvO), 142.0, 135.2, 129.6, 128.8,
128.6, 127.4, 125.4, 117.0; m/z (EI) 282 (Mþ).
4.1.19. 6-(4-Bromophenyl)thieno[2,3-d][1,3]dithiol-2-one
(28c). White powder, 0.16 g, 84%, mp 158–1608C. [Found:
C, 39.92, H, 1.65. C11H5BrOS3 requires C, 40.12, H,
1.52%]; dH (270 MHz) 7.53 (2H, d, J¼8.5 Hz, Ar), 7.39
(2H, d, J¼8.5 Hz, Ar), 7.29 (1H, s, vCH); dC 191.5
(CvO), 144.6 (qC), 132.4 (CH), 131.8 (qC), 128.3 (qC),
127.1 (CH), 122.5 (qC), 117.3 (CH); m/z (FAB, NOBA
matrix) 330 (Mþþ1).
4.1.20. 2-[4,5-Di(methylsulfanyl)-1,3-dithiol-2-ylidene]-
5-phenyl[1,3]dithiolo[4,5-b][1,4]dithiin (30a). A mixture

8114
F. Turksoy et al. / Tetrahedron 59 (2003) 8107–8116
of oxo compounds 27a (0.22 g, 0.8 mmol) and 29 (0.13 g,
0.9 mmol) was heated in freshly distilled (EtO)3P (20 mL)
under N2 atmosphere at 1108C for 3 h. The precipitate was
filtered and (EtO)3P was distilled off under reduced
pressure. The precipitate was characterized as 31a and the
residue was separated by column chromatography eluting
with hexane/CH2Cl2 (2/1). The first three fractions were
characterized as 32 (32 mg, 19%), the title compound 30a
(47 mg, 22%) and more 31a (76 mg, 18%). The desired
cross-coupling product 30a was recrystallized from ethanol
to give bright yellow needles, mp 54–568C. [Found: C,
41.35, H, 2.43. C16H12S8 requires C, 41.70, H, 2.60%]; dH
(270 MHz) 7.44 (2H, s, Ar), 7.28 (3H, s, Ar), 6.52 (1H, s,
vCH), 2.35 (6H, s, CH3); dC 142.3, 135.4, 129.3, 128.9,
128.7, 128.7, 128.6, 127.2, 118.6, 19.3 (CH3); m/z (EI) 460
(Mþ). 31a Light brown powder. [Found: C, 49.24, H, 2.07.
C22H12S8 requires C, 49.60, H, 2.25%]; dH (270 MHz) 7.53
(4H, m, Ar), 7.37 (6H, m, Ar), 6.61 (2H, s, vCH); d 142.4,
135.4, 129.4, 128.8, 127.2, 121.4, 121.2, 118.6; m/z (EI) 532
(Mþ).
C11H10S8 requires C, 33.16, H, 2.51%]; dH 6.09 (1H, s,
vCH), 2.10 (9H, s, 3£CH3); dH 137.9 (qC), 127.3 (qC),
120.1 (qC), 117.3 (CH), 114.3 (qC), 22.2 (CH3), 19.3
(2£SCH3); m/z (EI) 398 (Mþ).
4.1.24. 2-(5,6-Dihydro[1,3]dithiolo[4,5-b][1,4]dithiin-2-
ylidene)-5-(4-methoxyphenyl)[1,3]dithiolo[4,5-b]
[1,4]dithiin (34b). A mixture of 27b (0.10 g, 0.32 mmol)
and 33 (0.10 g, 0.48 mmol) was heated in freshly distilled
(EtO)3P (20 mL) under N2 atmosphere at 1108C for 3 h. The
precipitate was filtered and (EtO)3P was distilled off in
vacuo. The residue was separated by column chromato-
graphy eluting with hexane/CH2Cl2 (1/1). The second
fraction gave the title compound 34b as an orange powder
(31 mg, 20%), mp 165–1678C. [Found: C, 41.66, H, 2.51.
C17H12OS8 requires C, 41.80, H, 2.46%]; dH (270 MHz)
7.47 (2H, d, J¼8.7 Hz, Ar), 6.87 (2H, d, J¼8.7 Hz, Ar), 6.72
(1H, s, vCH), 3.81 (3H, s, CH3); HRMS (EI): Mþ, found
487.8659. C17H12OS8 requires 487.8653.
The following were similarly produced.
The following were similarly produced.
4.1.25. 2-(5,6-Dihydro[1,3]dithiolo[4,5-b][1,4]dithiin-2-
ylidene)-5-(4-bromophenyl)[1,3]dithiolo[4,5-b]
[1,4]dithiin (34c). The residue was separated by column
chromatography eluting with hexane/CH2Cl2 (2/1). The
second fraction gave the title compound 34c as an orange
powder (29 mg, 18%), mp 173–1758C. [Found: C, 35.48, H,
1.56. C16H9BrS8 C, 35.75, H, 1.67%]; dH (270 MHz) 7.48
(2H, d, J¼6.7 Hz, Ar), 7.4 (2H, d, J¼6.7 Hz, Ar), 6.61 (1H,
s, vCH) 3.30 (4H, s, 2£CH2); HRMS (EI): Mþ, found
537.7586. C16H9BrS8 requires 537.7632.
4.1.21. 2-[4,5-Di(methylsulfanyl)-1,3-dithiol-2-ylidene]-
5-(4-methoxyphenyl)[1,3]dithiolo[4,5-b][1,4]dithiin
(30b). The residue was separated by column chromato-
graphy eluting with hexane/CH2Cl2 (1/1). The middle
fraction gave the title compound 30b as bright yellow
needles (78 mg, 23%, recrystallized from ethanol), mp
110–1188C. [Found: C, 41.45, H, 2.52. C17H14OS8 requires
C, 41.60, H, 2.85%]; dH (270 MHz) 7.50 (2H, d, J¼9.0 Hz,
Ar), 6.87 (2H, d, J¼9.0 Hz, Ar), 6.45 (1H, s, vCH), 3.80
(3H, s, OCH3), 2.40 (6H, s, 2£CH3); dC 149.9, 142.4, 128.8,
128.6, 127.8, 121.4, 116.6, 116.0, 114.2, 114.1, 55.4
(OCH3), 19.3 (SCH3); m/z (EI) 490 (Mþ); m/z (FAB,
NOBA matrix) 490 (Mþ). 31b (third fraction) Yellow
powder (31 mg, 15%). [Found: C, 48.50, H, 2.58.
C24H16O2S8 requires C, 48.64, H, 2.70%]; dH (270 MHz)
7.49 (2H, d, J¼8.8 Hz, Ar), 6.87 (2H, d, J¼8.8 Hz, Ar), 6.46
(1H, s, vCH); dH (DMSO-d6, 270 MHz) 7.54 (2H, d,
J¼8.8 Hz, Ar), 6.98 (2H, d, J¼8.8 Hz, Ar), 7.05 (1H, s,
vCH); HRMS (EI): Mþ, found 591.8928. C24H16O2S8
requires 591.8916.
4.1.26. 2-(5,6-Dihydro[1,3]dithiolo[4,5-b][1,4]dithiin-2-
ylidene)-5-methyl[1,3]dithiolo[4,5-b][1,4]dithiin (34d).
The residue was separated by column chromatography
eluting with hexane/CH2Cl2 (2/1). The second fraction gave
the title compound 34d as an orange powder (27 mg, 15%),
mp 207–2108C. [Found: C, 33.25, H, 1.99. C11H8S8
requires C, 33.33, H, 2.02%]; dH (270 MHz) 6.53 (1H, s,
vCH), 3.23 (4H, s, 2£CH2), 2.11 (3H, s, CH3); HRMS (EI):
Mþ, found 395.8393. C11H8S8 requires 395.8391.
4.1.27. 2-[4,5-Di(methylsulfanyl)-1,3-dithiol-2-ylidene]-
6-phenylthieno[2,3-d][1,3]dithiole (35a). A mixture of
oxo compounds 28a (0.12 g, 0.48 mmol) and 29 (0.15 g,
0.72 mmol) was heated in freshly distilled (EtO)3P (20 mL)
under N2 atmosphere at 1108C for 3 h. The precipitate was
filtered and (EtO)3P was distilled off under reduced
pressure. The residue was separated by column chromato-
graphy eluting with hexane/CH2Cl2 (2/1). The first fraction
gave 35a as bright yellow needles (0.04 g, 20%, recrys-
tallized from ethanol), mp 145–1478C. [Found: C, 45.10, H,
2.53. C16H12S7 requires C, 44.85, H, 2.80%]; dH (270 MHz)
7.43 (2H, m, Ar), 7.35 (3H, m, Ar), 7.05 (1H, s, vCH), 2.44
(6H, s, 2£CH3); dC 129.0 (CH), 128.0 (CH), 125.2 (CH),
116.2 (CH), 19.2 (CH3); HRMS (EI): Mþ, found 427.8986.
C16H12S7 requires 427.8984.
4.1.22. 5-(4-Bromophenyl)-2-[4,5-di(methylsulfanyl)-1,3-
dithiol-2-ylidene][1,3]dithiolo[4,5-b][1,4]dithiin (30c). The
residue was separated by column chromatography eluting
with hexane/CH2Cl2 (2/1). The first fraction gave the title
compound 30c as yellow needles (80 mg, 25%, recrystal-
lized from ethanol), mp 153–1558C. [Found: C, 35.60, H,
2.04. C16H11BrS8 requires C, 35.25, H, 2.22%]; dH 7.50
(2H, d, J¼8.6 Hz, Ar), 7.40 (2H, d, J¼8.6 Hz, Ar), 6.61
(1H, s, vCH), 2.40 (6H, s, CH3). HRMS (EI): Mþ,
found 537.7820. C16H11BrS8 requires 537.7809. 31c
(third fraction) Yellow powder (41 mg, 16%). [Found: C,
38.26, H, 1.45. C22H10Br2S8 requires C, 38.45, H, 1.53%];
dH (DMSO-d6, 270 Hz) 7.57 (2H, d, J¼7.2 Hz, Ar), 7.54
(2H, d, J¼7.2 Hz, Ar), 7.24 (1H, s, vCH); m/z (EI) 690
(Mþ).
The following were similarly produced.
4.1.23. 2-[4,5-Di(methylsulfanyl)-1,3-dithiol-2-ylidene]-
5-methyl[1,3]dithiolo[4,5-b][1,4]dithiin (30d). Orange
powder (80 mg, 20%), [Found: C, 33.26, H, 2.21.
4.1.28. 2-[4,5-Di(methylsulfanyl)-1,3-dithiol-2-ylidene]-
6-(4-methoxyphenyl)thieno[2,3-d][1,3]dithiole
(35b).

F. Turksoy et al. / Tetrahedron 59 (2003) 8107–8116
8115
(EtO)3P was distilled off under reduced pressure and the
mixture was separated by column chromatography eluting
with hexane/CH2Cl2 (2/1). The second fraction gave the title
compound 35b as an orange powder (35 mg, 19%), mp
157–1608C. [Found: C, 44.14, H, 2.98. C17H14OS7 requires
C, 44.54, H, 3.05%]; dH (270 MHz) 7.40 (2H, d, J¼8.7 Hz,
Ar), 6.92 (2H, d, J¼8.7 Hz, Ar), 6.88 (1H, s, vCH), 3.83
(3H, s, OCH3), 2.44 (6H, s, 2£SCH3); dH 126.7, 122.9,
114.5, 114.4, 55.4 (OCH3), 19.2 (2£SCH3); HRMS (EI):
Mþ, found 457.9103. C17H14OS7 requires 457.9089.
36bþ37b (mixture, third fraction, 30 mg, 16%). [Found:
C, 54.65, H, 3.19. C24H16O2S6 requires C, 54.54, H, 3.03%];
dH (270 MHz) 7.53 (4H, d, J¼8.9 Hz, Ar), 6.93 (4H, d,
J¼8.9 Hz, Ar), 7.16 (2H, s, vCH), 7.14 (2H, s, vCH), 3.83
(6H, s, OCH3); m/z (EI) 528 (Mþ).
supporting this work (CGR 971021) and Figen Turksoy’s
PhD study, respectively, and TUBITAK for providing
instrumental facilities. We thank Dr Safiye S. Erdem of
Marmara University for her useful discussions on compu-
tational calculations and the EPSRC National X-ray
Crystallography Service for a dataset.
References
1. Williamas, J. M.; Ferraro, J. R.; Thorn, R. J.; Carlson, K. D.;
Geiser, U.; Wang, H. H.; Kini, A. M.; Whangbo, M.-H.
Organic Superconductors (Including Fullerenes); Prentice-
Hall: Englewood Cliffs, 1992. Bryce, M. R. J. Mater. Chem.
1995, 5, 1481–1496. Bryce, M. R. J. Mater. Chem. 2000, 10,
589–598.
4.1.29. 6-(4-Bromophenyl)-2-[4,5-di(methylsulfanyl)-1,3-
dithiol-2-ylidene]thieno[2,3-d][1,3]dithiole (35c). The
mixture was separated by column chromatography eluting
with hexane/ethyl acetate (7/3). The second fraction gave
the title compound 35c as a light orange powder (40 mg,
22%), mp 208–2108C. [Found: C, 38.05, H, 2.39.
C16H11S7Br requires C, 37.86, H, 2.17%]; dH (THF-d8,
270 MHz) 7.54 (2H, d, J¼7.8 Hz, Ar), 7.47 (2H, d,
J¼7.8 Hz, Ar), 7.36 (1H, s, vCH), 2.57 (6H, s, 2£SCH3);
dC (THF-d8) 133 (CH), 127.4 (CH), 18.9 (SCH3); HRMS
(EI): Mþ, found 507.8057. C16H11S7Br requires 507.8068.
2. Kini, A. M.; Geiser, U.; Wang, H. H.; Carlson, K. D.;
Williams, J. M.; Kwok, W. K.; Vandervoort, K. G.; Thompson,
J. E.; Stupka, D. L.; Jung, D.; Whangbo, M.-H. Inorg. Chem.
1990, 29, 2555–2557.
3. Andreu, R.; Barbera, J.; Garin, J.; Orduna, J.; Serrano, J. L.;
´
Sierra, T.; Leriche, P.; Salle, M.; Riou, A.; Jumbault, M.;
Gorgues, A. J. Mater. Chem. 1998, 8, 881–887.
4. Bryce, M. R.; Devonport, W.; Goldenberg, L. M.; Wang, C.
Chem. Commun. 1998, 945–951.
5. Christensen, C. A.; Goldenburg, L. M.; Bryce, M. R.; Becher,
J. Chem. Commun. 1998, 509–510.
4.1.30. 2-[6-(4-Methoxyphenyl)thieno[2,3-d][1,3]dithiol-
2-ylidene]-5,6-dihydro[1,3]dithiolo[4,5-b][1,4]dithiin
(38b). The precipitate, which was characterized as ET 2,
was filtered and the mixture was separated by column
chromatography eluting with hexane/CH2Cl2 (2/1). The first
and the second fractions gave ET and the title compound
38b, respectively, and the third fraction gave a mixture of
36b and 37b. 38b (37 mg, 20%) Light yellow powder, mp
177–1798C. [Found: C, 44.85, H, 2.59. C17H12OS7 requires
C, 44.73, H, 2.63%]; dH (270 MHz) 7.54 (2H, d, J¼8.7 Hz,
Ar), 7.13 (1H, s, vCH), 6.92 (2H, d, J¼8.7 Hz, Ar), 3.83
(3H, s, OCH3), 2.07 (4H, brs, 2£CH2); m/z (EI) 456 (Mþ).
6. Christensen, C. A.; Bryce, M. R.; Becher, J. Synthesis 2000,
1695–1704.
7. Huchet, L.; Akoudad, S.; Roncali, J. Adv. Mater. 1998, 10,
541–545. Skabara, P. J.; Roberts, D. M.; Serebryakov, I. M.;
Gozalo, C. P. Chem. Commun. 2000, 1005–1006.
8. Damgaard, D.; Nielsen, M. B.; Lau, J.; Jensen, K. B.; Zubarev,
R.; Levillain, E.; Becher, J. J. Mater. Chem. 2000, 14,
2249–2258. Nielsen, M. B.; Hansen, J. G.; Becher, J. Eur.
J. Chem. 1999, 2807–2815. Asakawa, M.; Ashton, P. R.;
Balzani, V.; Credi, A.; Hamers, C.; Mattersteig, G.; Montalti,
M.; Shipway, A. N.; Spencer, N.; Stoddart, J. F.; Tolley, M. S.;
Venturi, M.; White, A. J. P.; Williams, D. J. Angew. Chem.,
Int. Ed. 1998, 37, 333–337.
4.2. X-Ray analyses of 11
9. Yamada, J.-I.; Satoki, S.; Anzai, H.; Hagiya, K.; Tamura, M.;
Nishio, Y.; Kajita, K.; Watanabe, E.; Konno, M.; Sato, T.;
Nishikawa, H.; Kikuchi, K. Chem. Commun. 1996,
1955–1956. Skabara, P. J.; Serebryakov, I. M.; Roberts,
D. M.; Perepichka, I. F.; Coles, S. J.; Hursthouse, M. B. J. Org.
Chem. 1999, 64, 6418–6424. Nakamura, T.; Iwasaka, S.-I.;
Nakano, H.; Inoue, K.; Nogami, T.; Mikawa, H. Bull. Chem.
Soc. Jpn 1987, 60, 365–368. Xu, W.; Zhang, D. Q.; Li, H. X.;
Zhu, D. B. J. Mater. Chem. 1999, 9, 1245–1249. Bryce, M. R.;
Lay, A. K.; Batsanov, A. S.; Howard, J. A. K. Tetrahedron
Lett. 1999, 40, 801–804.
˚
C18H12S3, Mr¼324.9, monoclinic, a¼30.4496(4) A, b¼
3
˚
˚
˚
6.0673(8) A, c¼8.1449(10) A, b¼95.16(1)8, V¼1498.6 A ,
Cc, Z¼4, Dc¼1.43 g cm23
,
m(Mo Ka)¼4.8 cm21
,
T¼150 K, R(int)¼0.048, 1484 independent reflections,
final R1¼0.093 for 1297 reflections with F.4s(F). Very
thin crystals were grown from toluene. Data was collected
by the EPSRC X-ray crystallography service, using a Enraf
Nonius FAST system. The structure was solved with
SHELXS-9722 and refined with SHELXL-97.23 Crystallo-
graphic data (excluding structure factors) have been
deposited with the Cambridge Crystallographic Data Centre
as supplementary publication number CCDC 214528.
Copies of the data can be obtained, free of charge, on appli-
cationtoCCDC, 12UnionRd, Cambridge CB2 1EZ, UK (fax:
þ44-1223-336033 or email: deposit@ccdc.cam.ac.uk).
10. Ozturk, T. Tetrahedron Lett. 1996, 37, 2821–2824. Ertas, E.;
Ozturk, T. Chem. Commun. 2000, 2039–2040. Turksoy, F.;
Ozturk, T. Unpublished result. Ozturk, T.; Wallis, J. D. Acta
Crystallogr. Sect. C 1996, 52, 2552–2554.
11. Klar, G. Methods of Organic Chemistry, Schaumann, E., Ed.;
Thieme: Stuttgart, 1997; Vol. E9a, pp 250–407.
12. Svenstrup, N.; Becher, J. Synthesis 1995, 215–235.
13. Campaigne, E. Chem. Rev. 1946, 1, 39–58. Campaigne, E. In
The Chemistry of the Carbonyl Group; Patai, S., Ed.;
Interscience: New York, 1966; Chapter 17.
Acknowledgements
We thank the NATO and Istanbul Technical University for
14. Shridhar, D. R.; Jogibhukta, M.; Rao, P. S.; Handa, V. K.

8116
F. Turksoy et al. / Tetrahedron 59 (2003) 8107–8116
Synthesis 1982, 1061–1062. Wynberg, H.; Metselaar, J. Synth.
19. Freeman, F.; Kim, D. S. H. L.; Rodriguez, E. J. Org. Chem.
1992, 57, 1722–1727.
Commun. 1984, 14, 1. Kuroda, M.; Nakayama, J.; Hoshino,
M.; Furusho, N.; Ohba, S. Tetrahedron Lett. 1994, 35,
3957–3960.
20. Batanero, B.; Horcajada, R.; Mallmann, R.; Quintanilla, M. G.;
Barba, F. Electrochim. Acta 2002, 47, 1761–1764.
21. Eichinger, K.; Mayr, P.; Nussbaumer, P. Synthesis 1989,
210–211.
15. Cava, M. P.; Levinson, M. I. Tetrahedron 1985, 41,
5061–5087.
16. Horley, G. A.; Ozturk, T.; Turksoy, F.; Wallis, J. D. J. Chem.
Soc., Perkin Trans. 1 1998, 3225–3231.
22. Sheldrick, G. M. SHELXS-97: Program for the Solution of
Crystal Structures; University of Gottingen: Gottingen,
1997.
17. McCullough, R. D.; Belot, J. A.; Seth, J. J. Org. Chem. 1993,
58, 6480–6482. Moses, P. R.; Chambers, J. Q. J. Am. Chem.
Soc 1974, 96, 945–946.
23. Sheldrick, G. M. SHELXS-97: Program for the Refinement
of Crystal Structures; University of Gottingen: Gottingen,
1997.
18. Davies, A. G.; Schiesser, C. H. J. Organomet. Chem. 1990,
389, 301–313.