Synthesis of unsymmetrical tetrathiafulvalene derivatives via Me3Al-promoted reactions of organotin compounds with esters

Article abstract of DOI:10.1021/jo952255e

Efficient synthetic methods for the construction of a wide variety of unsymmetrical tetrathiafulvalenes (TTFs) via the Me₃Al-promoted reactions of organotin thiolates or selenolates with esters are described. Reaction of tin thiolates (3a-c and 10) and selenolates (3d, 5, and 7) with esters (11a,b) in the presence Of Me₃Al as a Lewis acid gave dihydrotetrathiafulvalene derivatives (12, 14, 15, and 17-20) and 1,3-dithiane derivatives (13 and 16). In addition, the synthesis of diselenadithiafulvalene derivatives (25-28) could be accomplished by Me₃Al-mediated reaction of tin thiolate (2a) or selenolates (3d and 5) with esters (22a, 22d, and 24). Furthermore, the application of the Me₃Al-promoted reaction of tin thiolate (34) with esters (11a-b, 22a-d, and 35a-b) for the synthesis of unsymmetrical TTFs-fused donors enabled us to obtain various TTFs-fused systems (29-33) in short steps.

Full text of DOI:10.1021/jo952255e

J . Org. Chem. 1996, 61, 3987-3995
3987
Syn th esis of Un sym m etr ica l Tetr a th ia fu lva len e Der iva tives via
Me3Al-P r om oted Rea ction s of Or ga n otin Com p ou n d s w ith Ester s
J un-ichi Yamada,* Shyuˆji Satoki, Sachinori Mishima, Nobutaka Akashi, Kouhei Takahashi,
Nobuyuki Masuda, Yasushi Nishimoto, Satoshi Takasaki, and Hiroyuki Anzai
Department of Material Science, Faculty of Science, Himeji Institute of Technology,
1479-1 Kanaji Kamigori-cho, Ako-gun, Hyogo 678-12, J apan
Received December 22, 1995X
Efficient synthetic methods for the construction of a wide variety of unsymmetrical tetrathiaful-
valenes (TTFs) via the Me3Al-promoted reactions of organotin thiolates or selenolates with esters
are described. Reaction of tin thiolates (3a -c and 10) and selenolates (3d , 5, and 7) with esters
(11a ,b) in the presence of Me3Al as a Lewis acid gave dihydrotetrathiafulvalene derivatives (12,
14, 15, and 17-20) and 1,3-dithiane derivatives (13 and 16). In addition, the synthesis of
diselenadithiafulvalene derivatives (25-28) could be accomplished by Me3Al-mediated reaction of
tin thiolate (2a ) or selenolates (3d and 5) with esters (22a , 22d , and 24). Furthermore, the
application of the Me3Al-promoted reaction of tin thiolate (34) with esters (11a -b, 22a -d , and 35a -
b) for the synthesis of unsymmetrical TTFs-fused donors enabled us to obtain various TTFs-fused
systems (29-33) in short steps.
In tr od u ction
stable at the low temperature.6 Subsequently, (DTEDT)
[Au(CN)2]0.4 has been ascertained to exhibit supercon-
ductivity with the transition temperature of 4 K.7 Thus,
in order to pursue further research on new organic metals
derived from unsymmetrical TTFs, the development of
synthetic methods that enable the efficient construction
of unsymmetrical TTFs is very important.
Recently, remarkable progress has been made in the
development of organic metals based on radical cation
salts of unsymmetrical tetrathiafulvalene (TTF) deriva-
tives. Following the discovery of superconductivities in
(DMET)2X1 and (MDT-TTF)2AuI2,2 the Ni(dmit)2 (dmit
) 4,5-dimercapto-1,3-dithiole-2-thione) salt of EDT-TTF
(ethylenedithiotetrathiafulvalene) has been found to be
an ambient pressure superconductor.3 In addition, a new
current appeared in the area of TTF chemistry in 1992.
Through the synthetic investigations on the bis-fused
TTF molecule4 and its analogs by Misaki,5 production of
a variety of TTFs-fused donors has become feasible, and
many charge-transfer complexes composed of unsym-
metrical TTFs-fused donors have been organic metals
In the conventional synthesis of TTF derivatives, the
coupling reaction utilizing trialkyl phosphite is a syn-
thetic approach to the construction of symmetrical TTFs.8
However, when this coupling reaction is applied to the
synthesis of unsymmetrical TTFs, two symmetrical self-
coupling products are formed along with the unsym-
metrical cross-coupling product (eq 1, Scheme 1). Espe-
cially, in the case of the synthesis of diselenadithia-
fulvalene (DSDTF) derivatives, the separation of the
desired cross-coupling product from self-coupling prod-
ucts is often troublesome.9 Meanwhile, we have found
that the non-phosphite coupling syntheses of unsym-
metrical TTFs such as DHTTF (dihydrotetrathiaful-
valene) derivatives, 1,3-dithiane derivatives, and DS-
DTFs are accomplished by Me3Al-promoted reaction of
organotin compounds with esters (eq 2).10,11 If this Me3-
Al-promoted reaction could be applicable to the synthesis
of unsymmetrical TTFs-fused donors, further extension
X Abstract published in Advance ACS Abstracts, May 15, 1996.
(1) DMET ) dimethyl(ethylenedithio)diselenadithiafulvalene, X )
Au(CN)2: Kikuchi, K.; Kikuchi, M.; Namiki, T.; Saito, K.; Ikemoto, I.;
Murata, K.; Ishiguro, T.; Kobayashi, K. Chem. Lett. 1987, 931-932. X
) AuCl2 and AuI2: Kikuchi, K.; Murata, K.; Honda, Y.; Namiki, T;
Saito, K.; Anzai, H.; Kobayashi, K.; Ishiguro, T.; Ikemoto, I. J . Phys.
Soc. J pn. 1987, 56, 4241-4244. X ) I3 and IBr2: Kikuchi, K.; Murata,
K.; Honda, Y.; Namiki, T.; Saito, K.; Ishiguro, T.; Kobayashi, K.;
Ikemoto, I. J . Phys. Soc. J pn. 1987, 56, 3436-3439. X ) AuBr2:
Kikuchi, K.; Murata, K.; Honda, Y.; Namiki, T.; Saito, K; Kobayashi,
K.; Ishiguro, T.; Ikemoto, I. J . Phys. Soc. J pn. 1987, 56, 2627-2628.
(2) MDT-TTF ) (methylenedithio)tetrathiafulvalene: (a) Kini, A.
M.; Beno, M. A.; Son, D.; Wang, H. H.; Carlson, K. D.; Porter, L. C.;
Welp, U.; Vogt, B. A.; Williams, J . M.; J ung, D.; Evain, M.; Whangbo,
M.-H.; Overmyer, D. L.; Schirber, J . E. Solid State Commun. 1989,
69, 503-507. (b) Papavassiliou, G. C.; Mousdis, G. A.; Zameounis, J .
S.; Terzis, A.; Hountas, A.; Hilti, B.; Mayer, C. W.; Pfeiffer, J . Synth.
Metals 1988, 27, B379-B383.
(6) (a) Misaki, Y; Kawakami, K; Fujiwara, H; Yamabe, T; Mori, T;
Mori, H; Tanaka, S. Chem. Lett. 1995, 1125-1126. (b) Mori, T.; Misaki,
Y.; Yamabe, T. Bull. Chem. Soc. J pn. 1994, 67, 3187-3190. (c) Mori,
T.; Inokuchi, H.; Misaki, Y.; Nishikawa, H.; Yamabe, T.; Mori, H.;
Tanaka, S. Chem. Lett. 1993, 2085-2088. (d) Misaki, Y.; Nishikawa,
H.; Yamabe, T.; Mori, T.; Inokuchi, H.; Mori, H.; Tanaka, S. Chem.
Lett. 1993, 1341-1344. (e) Mori, T.; Inokuchi, H.; Misaki, Y.; Nish-
ikawa, H.; Yamabe, T.; Mori, H.; Tanaka, S. Chem. Lett. 1993, 733-
736.
(7) DTEDT ) 2-(1,3-dithiol-2-ylidene)-5-(2-ethanediylidene-1,3-dithi-
ole)-1,3,4,6-tetrathiapentalene, which belongs to the vinylogous bis-
fused TTF system: Misaki, Y.; Higuchi, N.; Fujiwara, H.; Yamabe, T.;
Mori, T.; Mori, H.; Tanaka, S. Angew. Chem., Int. Ed. Engl. 1995, 34,
1222-1225.
(8) For general reviews, see: (a) Krief, A. Tetrahedron 1986, 42,
1209-1252. (b) Bryce, M. R. Aldrichimica Acta 1985, 18, 73-77. (c)
Schumaker, R. R.; Lee, V. Y.; Engler, E. M. J . Phys. 1983, 44, C-1139-
C-1145. (d) Narita, M.; Pittman, C. U. Synthesis 1976, 489-514.
(9) (a) Aonuma, S.; Okano, Y.; Sawa, H.; Kato, R.; Kobayashi, H. J .
Chem. Soc., Chem. Commum. 1992, 1193-1195. (b) Kobayashi, K.;
Kikuchi, K.; Namiki, T.; Ikemoto, I. Synth. Metals 1987, 19, 555-558.
(c) Kikuchi, K.; Namiki, T.; Ikemoto, I.; Kobayashi, K. J . Chem. Soc.,
Chem. Commun. 1986, 1472-1473.
(3) Tajima, H.; Inokuchi, M.; Kobayashi, A.; Ohta, T.; Kato, R.;
Kobayashi, H.; Kuroda, H., Chem. Lett. 1993, 1235-1238.
(4) This compound was initially proposed by Schumaker: Schu-
maker, R. R.; Engler, E. M. J . Am. Chem. Soc. 1977, 99, 5519-5521.
(5) (a) Misaki, Y.; Kawakami, K.; Mastui, T.; Yamabe, T.; Shiro, M.
J . Chem. Soc., Chem. Commun. 1994, 459-340. (b) Misaki, Y.;
Nishikawa, H.; Kawakami, K.; Yamabe, T; Mori, T.; Inokuchi, H; Mori,
H.; Tanaka, S. Chem. Lett. 1993, 2073-2076. (c) Misaki, Y.; Matsui,
T.; Kawakami, K.; Nishikawa, H.; Yamabe, T.; Shiro, M. Chem. Lett.
1993, 1337-1340. (d) Misaki, Y.; Nishikawa, H.; Yamabe, T.; Mori,
T.; Inokuchi, H.; Mori, H.; Tanaka, S. Chem. Lett. 1993, 729-732. (e)
Misaki, Y.; Kawakami, K.; Nishikawa, H.; Fujiwara, H.; Yamabe, T.;
Shiro, M. Chem. Lett. 1993, 445-448. (f) Misaki, Y.; Nishikawa, H.;
Kawakami, K.; Koyanagi, S.; Yamabe, T.; Shiro, M. Chem. Lett. 1992,
2321-2324. (g) Misaki, Y.; Nishikawa, H.; Fujiwara, H.; Kawakami,
K.; Yamabe, T.; Yamoti, H.; Saito, G. J . Chem. Soc., Chem. Commun.
1992, 1408-1409. (h) Misaki, Y.; Nishikawa, H.; Kawakami, K.;
Uehara, T.; Yamabe, T. Tetrahedron Lett. 1992, 33, 4321-4324.
S0022-3263(95)02255-9 CCC: $12.00 © 1996 American Chemical Society

3988 J . Org. Chem., Vol. 61, No. 12, 1996
Yamada et al.
Sch em e 1
F igu r e 1. DHTTF derivatives and 1,3-dithiane derivatives.
Sch em e 2
of the TTFs-fused systems would be possible. We now
report a full account of the Me3Al-promoted reaction and
application of this reaction to the synthesis of new
unsymmetrical TTFs-fused donors.
Resu lts a n d Discu ssion
P r ep a r a tion of Or ga n otin Th iola tes a n d Selen o-
la tes. Organotin thiolates 3a -c and selenolate 3d could
be prepared by trapping the corresponding dimagnesium
salts with Cl2SnBu2 (eq 3, Scheme 2). Treatment of
thiones 1a -c and selone 1d with Hg(OAc)2/THF-AcOH
gave ketones 2a -d (2a , 92% yield; 2b, 82% yield; 2c, 62%
yield; 2d , 72% yield). Grignard reaction of 2a -d in THF
followed by trapping with Cl2SnBu2 at -78 °C produced
organotin thiolates 3a -c and selenolate 3d . However,
direct transformation of thione 1a into tin thiolate 3a
via Grignard reaction was not successful. Although tin
thiolates 3a -c could not be purified by column chroma-
tography on silica gel, purification of tin selenolate 3d
in the same way was possible (81% yield). Organotin
selenolates 5 and 7 could be prepared via insertion
reaction of selenium into the carbon-lithium bond (eqs
4 and 5). Two consecutive stepwise reactions of 1,2-
LDA and elemental selenium13 followed by trapping with
Cl2SnBu2 in 60% yield (eq 5). Finally, though tin thiolate
10 could not be obtained via Grignard reaction of ketone
9 derived from 8, basic cleavage of 9 with NaOMe/MeOH
followed by treatment with Cl2SnBu2/THF gave 10 (eq
6). Tin thiolate 10 was used without purification through
silica gel. Conversion of ketone 2c into tin thiolate 3c
could also be carried out by basic cleavage with NaOMe/
MeOH, whereas transformation of 2a into 3a by a similar
procedure led to a decrease in yield of 3a .
Syn th esis of DHTTF Der iva tives a n d 1,3-Dith ia n e
Der iva tives. The results of Me3Al-promoted coupling
synthesis of DHTTF derivatives14 and 1,3-dithiane de-
rivatives (Figure 1) are summarized in Table 1. Tin
thiolate 3a reacted with 11a in the presence of Lewis
acids such as TiCl4, Me2AlCl, and Me3Al (entries 1-3).
However, reaction of 3a with 11a using BF3‚OEt2 as a
Lewis acid afforded only trace amounts of 12. Trimethyl-
t
dibromocyclopentene (4) in THF with 2 equiv of BuLi
and 1 equiv of elemental selenium12 followed by trapping
with Cl2SnBu2 at -78 °C enabled us to prepare 5 (eq 4).
Tin selenolate 5 tended to decompose through silica gel.
Preparation of tin selenolate 7 was carried out by
successive treatment of 2,3-dihydro-1,4-dithiin (6) with
(10) (a) Yamada, J .; Amano, Y.; Takasaki, S.; Nakanishi, R.;
Matsumoto, K.; Satoki, S.; Anzai, H. J . Am. Chem. Soc. 1995, 117,
1149-1150. (b) Yamada, J .; Takasaki, S.; Kobayashi, M.; Anzai, H.;
Tajima, N.; Tamura, M.; Nishio, Y.; Kajita, K. Chem. Lett. 1995, 1069-
1070.
(11) For the other non-phosphite coupling reactions, see: (a) Gimber,
Y.; Moradpour, A.; Dive, G.; Dehareng, D.; Lahlii, K. J . Org. Chem.
1993, 58, 4685-4690. (b) Sudmale, I. V.; Tormos, G. V.; Khodorkovsky,
V. Yu.; Edzine, A. S.; Neilands, O. J .; Cava, M. P. J . Org. Chem. 1993,
58, 1355-1358. (c) Mori, T.; Inokuchi, H. Chem. Lett. 1992, 1873-
1876. (d) Khodorkovsky, V. Yu.; Tormos, G. V.; Neilands, O. Ya.;
Kolotilo, N. V.; II′chenko, A. Ya. Tetrahedron Lett. 1992, 33, 973-976.
(e) J ørgensen, M.; Lerstrup, K. A.; Bechgaard, K. J . Org. Chem. 1991,
56, 5684-5688. (f) Mizuno, M.; Cava, M. P. J . Org. Chem. 1978, 43,
416-418. (g) Gonnella, N. C.; Cava, M. P. J . Org. Chem. 1978, 43,
369-370.
(13) Kato, R.; Kobayashi, H.; Kobayashi, A. Synth. Metals 1991, 41-
43, 2093.
(14) The synthesis and electrochemistry of DHTTF itself was
reported: Coffen, D. L.; Chambers, J . Q.; Williams, D. R.; Garrett, P.
E.; Canfield, N. D. J . Am. Chem. Soc. 1971, 93, 2258-2268. For some
recent works involving DHTTF derivatives, see: (a) Lorcy, D.; Paillard,
M.-P. L.; Robert, A. Tetrahedron Lett. 1993, 34, 5289-5292. (b) Salle,
M.; Gorgues, A.; J ubault, M.; Gouriou, Y. Synth. Metals 1991, 41-43,
2575-2578.
(12) Okano, Y.; Sawa, H.; Aonuma, S.; Kato, R. Chem. Lett. 1993,
1851-1854.

Synthesis of Unsymmetrical Tetrathiafulvalene Derivatives
J . Org. Chem., Vol. 61, No. 12, 1996 3989
Ta ble 1. Syn th eses of DHTTF Der iva tives a n d
1,3-Dith ia n e Der iva tives
Sch em e 3
organotin
entry compound ester
Lewis
acid
temp,
°C
reaction pro- yield
time duct (%)
1
2
3
4
5
6
7
8
9
3a
3a
3a
3a
10
3b
3b
3b
3c
3d
5
11a TiCl4
-78 f rta overnight 12 28b,c
11a Me2AlCl -78 f rt overnight 12 44b,c
11a Me3Al
11b Me3Al
11a Me3Al
11a Me3Al
11a Me3Al
11b Me3Al
11a Me3Al
11a Me3Al
11a Me3Al
11a Me3Al
-78 f rt overnight 12 57b,c
-78 f rt overnight 13 61b,c
-78 f rt overnight 14 26d,e
-78 f rt overnight 15
-78 f 15 3 h
-78 f rt 6 h
9d,f
15 36d,f
16 22b,f
17 67b,g
18 83b
19 33b,h
20 42b
Sch em e 4
rt
rt
rt
rt
3 days
10
11
12
6 days
5 days
6 days
7
a
b
Room temperature. After column chromatography on silica
gel. c Overall yield from 2a . After column chromatography fol-
d
lowed by recrystallization. e Overall yield from 9. f Overall yield
g
h
from 2b. Overall yield from 2c. Overall yield from 4.
aluminum gave the best result among the Lewis acids
examined. Similarly, the Me3Al-mediated reaction of 3a
with 11b produced the 1,3-dithiane derivative 13 in 61%
yield based on 3a (entry 4). A dihydro-analog of MDT-
TTF 14 could also be prepared by the Me3Al-mediated
reaction of 10 with 11a (entry 5). A vinylenedithio-
annelated DHTTF 15 seems to be sensitive to the acidic
conditions, since the treatment of 3b with 11a for a
prolonged period resulted in a decrease in yield of 15
(entry 6). Therefore, we shortened the reaction time
when treatment of 3b with both 11a and 11b was carried
out (entries 7 and 8). A thieno-annelated DHTTF 17
could be formed slowly by reaction of 3c with 11a (entry
9). An alternative synthetic method of 17 is as follows.
Similarly to preparation of 5 (eq 4, Scheme 2), except for
the addition of elemental sulfur instead of Se powder,
two consecutive stepwise reactions of 3,4-dibromothiophene
followed by treatment with Cl2SnBu2 gave 3c. Reaction
of 3c with 11a in the presence of Me3Al afforded 17 in
ca.19% overall yield from 3,4-dibromothiophene. How-
ever, the isolated 17 via this synthetic route contained
small amounts of impurities. The reaction of tin sele-
nolates 3d , 5, and 7 was relatively very slow in compari-
son with the reaction of tin thiolates, but the selenium
analog of DHTTF derivatives 18-20 could be prepared
by this Me3Al-mediated coupling reaction (entries 10-
12).
P r ep a r a tion of Ester s. We investigated the syn-
thetic method for the preparation of esters 22 and 24
(Scheme 3) so as to construct the other unsymmetrical
TTFs, i.e., DSDTF derivatives and unsymmetrical TTFs-
fused donors, by the Me3Al-promoted reactions. Trans-
metalation of organotin compounds 3a , 21 (prepared from
4,5-dimethyl-1,3-dithiol-2-one via Grignard reaction), 3d ,
and 5 with 2 equiv of n-butyllithium at -78 °C followed
by treatment with methyl dichloroacetate gave the
desired esters 22a -d (eq 7: 22a , 35% yield based on 2a ;
22b, 41% yield based on 4,5-dimethyl-1,3-dithiol-2-one;
22c, 73% yield; 22d , 54% yield based on 4). Ester 22d
could also be prepared by direct reaction of the dilithium
salt of cyclopentene-1,2-diselenol with methyl dichloro-
acetate in 50% overall yield from 4. In the case of
preparation of ester 24 with a 1,2,5-thiadiazole ring (eq
8), basic cleavage of TDA-DTC (23)15 with NaOMe/MeOH
followed by treatment with methyl dichloroacetate in
THF was carried out (44% yield).
Syn th esis of DSDTF Der iva tives. Tin selenolate 3d
reacted smoothly with 22a in the presence of Me3Al, and
DMET (25) was obtained in 43% yield (eq 9, Scheme 4).
Similarly, the Me3Al-promoted reaction of ester 22d with
tin thiolate 2a produced TMET-STF16 (26) in 37% yield
(eq 10). On the other hand, under the same operating
conditions as used for synthesis of 25 and 26, the yield
of a thiadiazolo-fused DSDTF derivative 27 was only 3%
even though the reaction time was prolonged. Accord-
ingly, preparation of 27 and 28 was carried out under
alternative operating conditions. Tin selenolate 3d or 5
was first reacted with Me3Al at room temperature in CH2-
Cl2, and then ester 24 was added. Under these operating
conditions the yields of 27 and 28 were 27% and 12%,
respectively. Although, at present, there exists no direct
(15) TDA-DTC ) thiadiazole(dithiocarbonate): Underhill, A. E.;
Hawkins, I.; Edge, S.; Wilkes, S. B.; Varma, K. S.; Kobayashi, A.;
Kobayashi, H. Synth. Metals 1993, 55-57, 1914-1019.
(16) TMET-STF ) Trimethylene(ethylenedithio)diselenadithiaful-
valene, see ref 12.

3990 J . Org. Chem., Vol. 61, No. 12, 1996
Yamada et al.
Ta ble 2. Me3Al-P r om oted Rea ction of th e Tin Th iola te
34 w ith Ester s
reaction conditions
isolated
entry ester
solvent
35a CH2Cl2
35b CH2Cl2
temp
time
product yield (%)
1
2
rta 4 days
rt
rt
rt
36a
36b
36c
36d
36d
36e
36e
36e
36f
36g
36h
35b
52b
48b
9b
3 days
2 days
5 days
5 days
overnight
overnight
2 days
overnight
4 days
3
4
11a CH2Cl2
11b CH2Cl2
5
6
11b ClCH2CH2Cl rt
22a ClCH2CH2Cl rt
23c
9c
7
8
9
10
11
22a CH2Cl2
22a CH2Cl2
22b CH2Cl2
22c CH2Cl2
22d CH2Cl2
rt
rt
rt
rt
rt
11c
trace
12b
33c
16c
overnight
a
b
Room temperature. After column chromatography on silica
gel. c After column chromatography on silica gel followed by
recrystallization.
F igu r e 2. Unsymmetrical TTFs-fused donors.
Ta ble 3. Cr oss-Cou p lin g Rea ction betw een Keton es a n d
Th ion es
Sch em e 5
ketone
thione
product
yield (%)
36a
36b
36c
36c
36c
36d
36d
36d
36f
36g
36h
37a
37a
37b
1a
8
37b
1a
8
1c
37b
37b
29a
29b
30a
30b
30c
31a
31b
31c
32
20a
26a
47a
80b
28a
43b
62a
16a
7a
33a
33b
46a
36a
a
After column chromatography on silica gel followed by recrys-
b
tallization. After column chromatography on silica gel.
room temperature for 40 min prior to addition of esters.
Preparation of ketones 36a and 36b in five steps from
the Zn(dmit)2 complex is known,5h while we demonstrated
that these compounds can be prepared in two steps from
thiapendione via the Me3Al-mediated coupling reactions
(entries 1 and 2). Reaction of 34 with ester 11a gave
ketone 36c as a key intermediate for the formation of
the TTFs-DHTTF fused system (entry 3). Changing the
solvent used for the reaction with 11b from dichlo-
romethane to 1,2-dichloroethane led to a increase in yield
of 36d (entries 4 and 5). On the other hand, the yield of
36e was not influenced by the solvent employed for the
reaction with 22a (entries 6 and 7), although the length
of the reaction time had some effect (entry 8). Similarly
to preparation of 36e, reaction with 22b afforded ketone
36f5a leading to the bis-fused TTFs system (entry 9).
Furthermore, the Me3Al-promoted reaction of 34 with
both 22c and 22d produced the selenium-introduced
ketones 36g and 36h (entries 10 and 11). Such ketones
have not so far been prepared by conventional synthetic
methods.
Next we attempted to construct the TTFs-fused sys-
tems from 36 by the Me3Al-promoted reaction; however,
for example, conversion of 36c into the corresponding tin
thiolate was unsuccessful due to its insolubility in
appropriate solvents used for the Grignard reaction. In
general, ketones 36c-h were not sufficiently soluble in
common organic solvents, except for carbon disulfide.
Thus, transformations of 36a -h into the unsymmetrical
TTFs-fused donors 29-33 were performed by the cross-
coupling reactions with 2 equiv of the appropriate 1,3-
dithiole-2-thiones 37a ,b, 1a , 1c, and 8 in P(OMe)3/boiling
PhMe (v/v ) 1/1) for 2 h.5a-d The isolated products by
either column chromatography on silica gel or column
evidence for the mechanism of this reaction, the initially
formed aluminium selenolate by the tin-aluminium
exchange reaction of 3d or 5 with Me3Al presumably
reacted with ester 24.
Syn th esis of Un sym m etr ica l TTF s-F u sed Don or s
via th e Me3Al-P r om oted Rea ction . As mentioned
above, we have established an efficient synthetic method
for the construction of DHTTFs, 1,3-dithiane derivatives,
and DSDTFs without separation from self-coupling prod-
ucts. Our next target is to develop a method for the new,
and short-step synthesis of TTFs-fused systems 29-33
(Figure 2) via the Me3Al-promoted reaction of the orga-
notin thiolate (34, Scheme 5) with esters (35a -b, 11a -b,
and 22a -d ).
Scheme 5 outlines our synthetic method for the con-
struction of TTFs-fused systems. Treatment of thiapen-
dione17 with NaOMe (2 equiv)/MeOH18 followed by trap-
ping with Cl2SnBu2/THF at -78 °C gave organotin
thiolate 34 in 96% yield. Reaction of 34 with esters 35a -
b, 11a -b, and 22a -d in the presence of Me3Al was
examined, and the results are summarized in Table 2.
In all cases, tin thiolate 34 was reacted with Me3Al at
(17) Schumaker, R. R.; Engler, E. M. J . Am. Chem. Soc. 1977, 99,
5521-5522.
(18) Mu¨ller, H.; Ueba, Y. Synthesis 1993, 853-854.

Synthesis of Unsymmetrical Tetrathiafulvalene Derivatives
J . Org. Chem., Vol. 61, No. 12, 1996 3991
presence of triethylamine. 4,5-Bis(methylthio)-1,3-dithiole-2-
thione (37b) was prepared according to the literature.24
A Typ ica l P r oced u r e for Con ver sion of Th ion es in to
Keton es. Conversion of thione 1a into ketone 2a is repre-
sentative. In a 300-mL flask were placed 80 mL of THF
(distilled from CaH2) and 1.12 g (5.0 mmol) of 1a . A solution
of Hg(OAc)2 (2.39 g, 7.5 mmol) in acetic acid (80 mL) was
added, and the mixture was stirred vigorously at room
temperature for 30 min. The reaction mixture was filtered
through Celite, and the solution was diluted with dichlo-
romethane and water. The organic layer was washed succes-
sively with several portions of water and saturated aqueous
NaHCO3 solution, dried over MgSO4, and then concentrated
under reduced pressure. Purification of the residue with silica
gel column chromatography by using dichloromethane as an
eluent followed by recrystallization from ethanol gave 0.96 g
(92% yield) of 2a .
4,5-(Eth ylen ed ith io)-1,3-d ith iol-2-on e (2a ): pale yellow
needles; mp 127-128 °C (lit.18 mp 127-128 °C); 1H NMR
(CDCl3) δ 3.43 (s, 4 H); 13C NMR (CDCl3) δ 31.2, 113.5, 188.9;
MS, m/z (% relative intensity) 210 (M+ + 2, 17), 208 (M+, 100),
182 (8), 180 (42); HRMS (EI) calcd for C5H4OS4 207.9145,
measured 207.9145.
4,5-(Vin ylen ed ith io)-1,3-d ith iol-2-on e (2b): pale orange
needles; mp 98-99 °C from ethanol (lit.22 mp 99 °C); 1H NMR
(CDCl3) δ 6.62 (s, 2 H); 13C NMR (CDCl3) δ 117.3, 124.0, 192.4;
MS, m/z (% relative intensity) 208 (M+ + 2, 22), 206 (M+, 100),
180 (14), 178 (63), HRMS (EI) calcd for C5H2OS4 205.8989,
measured 205.8987.
chromatography followed by recrystallization were the
desired cross-coupling products 29-33 (Table 3). Under
similar conditions, cross-coupling reaction of 36e with
37a or 1c (a 0.16 or 0.39 mmol scale) gave trace amounts
of the desired product. Eventually, we have accom-
plished the three-step synthesis of unsymmetrical TTFs-
fused donors, including 33a and 33b as one of the two
TTFs-DSDTFs systems respectively, via the Me3Al-
mediated reaction.
Con clu sion
The conversion of esters into dithioketene acetals by
the use of aluminium thiolates19 and the application of
this transformation for the synthesis of unsymmetrical
TTFs20 have been already reported. In contrast to these
reports, our synthetic concept is as follows. Magnesium,
lithium, or sodium chalcogenides are transformed to the
stable tin chalcogenides (stabilization), which are sub-
sequently reacted with esters in the presence of Me3Al
(activation). The present work reveals that this stabili-
zation-activation procedure21 is not only useful for the
synthesis of various unsymmetrical TTFs, but also ap-
plicable for the preparation of a variety of highly desir-
able analogs since both tin compounds and esters are
readily obtainable by standard procedures.
Th ien o[3,4-d ]-1,3-d it h iol-2-on e (2c): brownish white
needles; mp 103-104 °C from ethanol (lit.23 mp 107-108 °C);
1H NMR (CDCl3) δ 7.31 (s, 2 H); 13C NMR (CDCl3) δ 115.4,
128.5, 193.9; MS, m/z (% relative intensity) 176 (M+ + 2, 55),
174 (M+, 100), 148 (25), 146 (50); HRMS (EI) calcd for C5H2-
OS3 173.9268, measured 173.9270.
Exp er im en ta l Section
Gen er a l Meth od s. Melting points are uncorrected. 1H-
NMR spectra were run at 400 MHz. 13C-NMR spectra were
recorded at 100 MHz. 1H-NMR chemical shifts are expressed
in parts per million (δ) relative to CHCl3 (δ 7.26) as an internal
reference. For 13C-NMR chemical shifts, reference was the
center peak of chloroform-d (δ 77.1). Air- and/or moisture-
sensitive reactions were carried out in a dry reaction flask
under nitrogen.
4,5-Dim eth yl-1,3-diselen ol-2-on e (2d): pale yellow needles;
1
mp 42-43 °C from ethanol; H NMR (CDCl3) δ 2.24 (s, 6 H);
13C NMR (CDCl3) δ 15.8, 128.6, 188.4; MS, m/z (% relative
intensity) 244 (M+ + 4, 32), 242 (M+ + 2, 100), 240 (M+, 88),
238 (M+ - 2, 53), 216 (18), 214 (45), 212 (42), 210 (27); HRMS
(EI) calcd for C5H6OSe2 241.8749, measured 241.8744.
4,5-(Meth ylen ed ith io)-1,3-d ith iol-2-on e (9). The same
procedure as described above in A Typical Procedure was
employed except for using 2 equiv of Hg(OAc)2. Purification
of the product with column chromatograpy on silica gel gave
9 in 92% yield from 8: pale brown needles; mp 101-102 °C
from ethanol; 1H NMR (CDCl3) δ 4.74 (s, 2 H); 13C NMR
(CDCl3) δ 38.4, 114.0, 193.0; MS, m/z (% relative intensity)
196 (M+ + 2, 20), 194 (M+, 100), 168 (7), 166 (30); HRMS (EI)
calcd for C4H2OS4 193.8989, measured 193.8990.
Ma ter ia ls. Tetrahydrofuran was distilled from sodium
benzophenone ketyl under an argon atmosphere unless oth-
erwise noted. Diisopropylamine was distilled from CaH2 and
stored under an argon atmosphere. All other solvents were
dried by appropriate procedures, and stored over molecular
sieves. Trimethylaluminium/hexane, n-butyllithium/hexane,
t-butyllithium/pentane, sodium methylate/methanol, and me-
thylmagnesium bromide/tetrahydrofuran were purchased from
Kanto Chemical Co. 4,5-(Ethylenedithio)-1,3-dithiole-2-thione
(1a ), 4,5-(methylenedithio)-1,3-dithiole-2-thione (8), ethyl 1,3-
dithiolane-2-carboxylate (11a ), ethyl 1,3-dithiane-2-carboxylate
(11b), and thiapendione (1,3,4,6-tetrathiapentalene-2,5-dione)
were purchased from Tokyo Kasei Kogyo Co. 4,5-(Vinylene-
dithio)-1,3-dithiole-2-thione (1b) and thieno[3,4-d]-1,3-dithiole-
2-thione (1c) were prepared essentially according to the
literature.22 4,5-Dimethyl-1,3-diselenole-2-selone (1d ) was
prepared by the known method.23 4,5-Dimethyl-1,3-dithiol-2-
one was synthesized by reaction of 3-bromo-2-butanone with
potassium isopropylxanthate followed by treatment with concd
H2SO4. Methyl cyclopentanecarboxylate (35b) was obtained
by esterification (concd H2SO4/MeOH) of cyclopentanecarboxy-
lic acid. Benzo[d]-1,3-dithiole-2-thione (37a ) was synthesized
by reaction of 1,2-benzenedithiol with thiophosgene in the
A Typ ica l P r oced u r e for Con ver sion of Keton es in to
Tin Com p ou n d s via Gr ign a r d Rea ction . Transformation
of ketone 2a into tin thiolate 3a is representative. To a
solution of 2a (1.04 g, 5.0 mmol) in THF (50 mL) was added
dropwise a THF solution of MeMgBr (0.90 M × 18.3 mL, 16.5
mmol) at 0 °C. The mixture was warmed to room temperature
and stirred for 2 h. After the reaction mixture was cooled to
-78 °C, a solution of Cl2SnBu2 (1.67 g, 5.3 mmol) in THF (25
mL) was added dropwise for 30 min, and stirring was
continued for 1 h at that temperature. The mixture was
allowed to warm to 0 °C, and the reaction was quenched by
the addition of saturated aqueous NaCl solution. The result-
ing suspension was filtered through Celite, and the aqueous
layer was extracted with three portions of chloroform. The
organic extracts were combined and dried over MgSO4. Re-
moval of the solvent under reduced pressure gave the crude
3a as a yellow solid.
4,5-(Eth ylen ed ith io)-2,2-d ibu tyl-2-sta n n a -1,3-d ith iole
(3a ): mp 113-115 °C; 1H NMR (CDCl3); δ 0.93 (t, J ) 7.3 Hz,
6 H), 1.36 (sixtet, J ) 7.3 Hz, 4 H), 1.66 (m, 4 H), 1.73 (m, 4
H); 13CMR (CDCl3) δ 13.6, 22.3, 26.7, 27.9, 33.3, 116.8.
4,5-(Vin ylen ed it h io)-2,2-d ibu t yl-2-st a n n a -1,3-d it h iole
(3b): viscous brown solid; 1H NMR (CDCl3); δ 0.92 (t, J ) 7.3
Hz, 6 H), 1.36 (sixtet, J ) 7.3 Hz, 4 H), 1.66-1.77(m, 8 H)
6.47 (s, 2 H); 13CMR (CDCl3) δ 13.6, 23.9, 26.6, 27.7, 121.0,
125.2.
(19) (a) Cohen, T.; Gapinski, R. E.; Hutchins, R. R. J . Org. Chem.
1979, 44, 3599-3601. (b) Corey, E. J .; Beames, D. J . J . Am. Chem.
Soc. 1973, 95, 5829-5831.
(20) Mori, T.; Inokuchi, H. Chem. Lett. 1992, 1873-1876.
(21) Yamada, J .; Yamamoto, Y. Rev. Heteroatom Chem. 1991, 5,
250-269.
(22) For 1b: Nakamura, T.; Nogami, T.; Shirota, Y. Bull. Chem.
Soc. J pn. 1987, 60, 3447-3449. For 1c: Chiang, L.-Y.; Shu, P.; Holt,
D. ; Cowan, D. J . Org. Chem. 1983, 48, 4713-4717.
(23) Moradpour, A.; Peyrussan, V.; J ohansen, I.; Bechgaard, K. J .
Org. Chem. 1983, 48, 388-389.
(24) Steimecke, G.; Sieler, H.-J .; Kirmse, R.; Hoyer, E. Phosphorus
Sulfur 1979, 7, 49-55.

3992 J . Org. Chem., Vol. 61, No. 12, 1996
Yamada et al.
Th ien o[3,4-d]-2,2-dibu tyl-2-stan n a-1,3-dith iole (3c). The
same procedure as described above in A Typical Procedure was
used except that reaction of 2c with MeMgBr was carried out
for 3 h: brownish-white solid; mp 49-50 °C; 1H NMR (CDCl3);
δ 0.92 (t, J ) 7.3 Hz, 6 H), 1.37 (sixtet, J ) 7.3 Hz, 4 H), 1.67
(m, 4 H), 1.73 (m, 4 H); 13CMR (CDCl3) δ 13.6, 22.7, 26.7, 27.9,
117.6, 136.9.
purification was carried out within a short period, since 7 was
sensitive to silica gel: reddish brown powder; mp 77-79 °C;
1H NMR (CDCl3) δ 0.92 (t, J ) 7.3 Hz, 6 H), 1.36 (sixtet, J )
7.3 Hz, 4 H), 1.71 (m, 8 H), 3.20 (s, 4 H); 13C NMR (CDCl3) δ
13.6, 21.3, 26.6, 28.6, 33.3, 112.6.
4,5-(Met h ylen ed it h io)-2,2-d ib u t yl-2-st a n n a -1,3-d it h i-
ole (10). A 100-mL flask with a septum inlet containing 389
mg (2.0 mmol) of 9 was cooled in a water bath, and a methanol
solution of NaOMe (1 M × 4.0 mL, 4.0 mmol) was added in
one portion via a syringe. After stirring for 10 min, the water
bath was removed, and the mixture was diluted with 10 mL
of THF. A solution of Cl2SnBu2 (608 mg, 2.0 mmol) in THF
(20 mL) was added dropwise at -78 °C for 30 min, and the
resulting mixture was warmed to 0 °C gradually. The reaction
was quenched by the addition of saturated aqueous NaCl
solution, and the aqueous layer was extracted with three
portions of dichloromethane. The extracts were combined and
dried over MgSO4. Removal of the solvent under reduced
pressure gave a viscous deep violet oil. When 10 was kept at
room temperature for a prolonged time, decomposition of 10
took place gradually: 1H NMR (CDCl3) δ 0.93 (t, J ) 7.3 Hz,
6 H), 1.37 (sixtet, J ) 7.3 Hz, 4 H), 1.63-1.78 (m, 8 H), 4.55
(s, 2 H). The exact assignment for 10 could not be made on
the basis of 13C NMR analysis due to impurities.
Th ien o[3,4-d]-2,2-dibu tyl-2-stan n a-1,3-dith iole (3c). The
same procedure as described above was used. The usual
workup led to the crude tin thiolate 3c, which was identical
with the sample prepared via Grignard reaction of 2c.
A Typ ica l P r oced u r e for Syn th eses of DHTTF Der iva -
tives a n d Rela ted Com p ou n d s. Entry 3 in Table 1 is
representative. In a 50-mL flask with a septum inlet were
placed 2.0 mmol (based on 2a ) of tin thiolate 3a and 30 mL of
dichloromethane, and the mixture was cooled to -78 °C. A
hexane solution of Me3Al (1.02 M × 4.0 mL, 4.1 mmol) and
0.28 mL (2.0 mmol) of ester 11a were successively added via
syringes, and the reaction mixture was allowed to warm up
to room temperature. After stirring at room temperature
overnight, the reaction was quenched by the addition of
saturated aqueous NaHCO3 solution at 0 °C, and the resulting
suspension was filtered through Celite. The aqueous layer was
extracted with three portions of chloroform. The extracts were
combined, dried over MgSO4, and then concentrated in vacuo.
Purification of the residue with silica gel column chromatog-
raphy by using hexane followed by hexane-dichloromethane
as eluents gave 338 mg (57% yield) of 12.
4,5-Dim eth yl-2,2-d ibu tyl-2-sta n n a -1,3-d iselen ole (3d ).
The same procedure as described above in A Typical Procedure
was performed except that (i) reaction of 2d with MeMgBr was
carried out for 4.5 h, and (ii) the product was purified by silica
gel column chromatography using hexane-dichloromethane
1
as an eluent: orange oil; H NMR (CDCl3) δ 0.93 (t, J ) 7.3
Hz, 6 H), 1.37 (sixtet, J ) 7.3 Hz, 4 H), 1.58 (m, 4 H), 1.70 (m,
4 H), 2.07 (s, 6 H); 13CMR (CDCl3) δ 13.6, 20.4, 23.7, 26.6, 28.7,
124.4.
4,5-Dim eth yl-2,2-dibu tyl-2-stan n a-1,3-dith iole (21). The
same procedure as described above in A Typical Procedure was
employed except that (i) reaction of 4,5-dimethyl-1,3-dithiol-
2-one with MeMgBr was carried out for 4 h and (ii) purification
by silica gel column chromatography (hexane-dichloromethane)
could be carried out (80% yield from 4,5-dimethyl-1,3-
dithiol-2-one): pale yellow powder; mp 65-66 °C; 1H NMR
(CDCl3) δ 0.92 (t, J ) 7.3 Hz, 6 H), 1.36 (sixtet, J ) 7.3 Hz, 4
H), 1.55 (m, 4 H), 1.70 (m, 4 H), 2.01 (s, 6 H); 13CMR (CDCl3)
δ 13.6, 21.3, 22.7, 26.7, 27.9, 123.0.
4,5-Tr im eth ylen e-2,2-dibu tyl-2-stan n a-1,3-diselen ole (5).
In a 100-mL flask with a septum inlet were placed 0.60 mL
(5.0 mmol) of 1,2-dibromocyclopentene and 30 mL of THF, and
the mixture was cooled to -78 °C. A pentane solution of
tBuLi (1.60 M × 6.3 mL, 10 mmol) was added via a syringe,
and the mixture was stirred at -78 °C for 2.5 h. After the
reaction solution was warmed to -20 °C, selenium powder (395
mg, 5 mmol) was added and the resulting mixture was stirred
at -20 °C for an additional 0.5 h. Once again, the reaction
solution was cooled to -78 °C, and the addition of a solution
of tBuLi in pentane (1.60 M × 6.3 mL, 10 mmol) was repeated.
After stirring at -78 °C for 2.5 h, the mixture was warmed
up to room temperature, and then selenium powder (395 mg,
5 mmol) was added. The resulting mixture was stirred at room
temperature for 30 min, and a solution of Cl2SnBu2 (1.52 g,
5.0 mmol) in THF (20 mL) was added dropwise for 40 min at
-78 °C. The reaction mixture was allowed to warm up to room
temperature and stirred at that temperature overnight. The
reaction was quenched by the addition of saturated aqueous
NaCl solution, and the resulting suspension was filtered
through Celite. After the aqueous layer was extracted with
three portions of dichloromethane, the extracts were combined
and dried over MgSO4. Removal of the solvent under reduced
pressure gave a deep brown oil: 1H NMR (CDCl3) δ 0.91 (t, J
) 7.3 Hz, 6 H), 1.36 (sixtet, J ) 7.3 Hz, 4 H), 1.61 (m, 4 H),
1.68 (m, 4 H), 2.14 (quintet, J ) 7.3 Hz, 2 H), 2.47 (t, J ) 7.3
Hz, 4 H); 13C NMR (CDCl3) δ 13.6, 21.8, 26.5, 27.0, 28.5, 38.7,
132.0.
(Eth ylen ed ith io)d ih yd r otetr a th ia fu lva len e (12): or-
1
ange powder; mp 223.5 °C dec from ethanol-chloroform; H
NMR (CDCl3) δ 3.28 (s, 4 H), 3.47 (s, 4 H); 13C NMR (CDCl3)
δ 30.2, 40.0, 109.3, 113.3, 118.9; MS, m/z (% relative intensity)
298 (M+ + 2, 30), 296 (M+, 100), 268 (51), 192 (30), 148 (30),
83 (70); HRMS (EI) calcd for C8H8S6 295.8950, measured
295.8951.
2-[4,5-(E t h ylen ed it h io)-1,3-d it h iol-2-ylid en e]-1,3-d i-
th ia n e (13): yellow powder; mp 152-153 °C from ethanol-
1
chloroform; H NMR (CDCl3) δ 2.17 (m, 2 H), 2.85 (m, 4 H),
4,5-(E t h ylen ed it h io)-2,2-d ib u t yl-2-st a n n a -1,3-d isele-
n ole (7). In a 30-mL flask with a septum inlet were placed
0.42 mL (3.0 mmol) of diisopropylamine and 2 mL of THF,
and the mixture was cooled to 0 °C. A hexane solution of
nBuLi (1.71 M × 1.75 mL, 3.0 mmol) was added via a syringe,
and the mixture was stirred at 0 °C for 10 min. The reaction
solution was cooled to -78 °C, a solution of 2,3-dihydro-1,4-
dithiin (118 mg, 1.0 mmol) in THF (3 mL) was added dropwise
slowly. After stirring at -78 °C for 15 min, selenium powder
(158 mg, 2.0 mmol) was added and the resulting mixture was
warmed to -40 °C gradually. The reaction solution was
maintained at -40 °C for 20 min to afford a pale yellow
solution. A solution of Cl2SnBu2 (608 mg, 2.0 mmol) in THF
(10 mL) was added dropwise at -78 °C for 20 min, and the
mixture was allowed to warm to 0 °C. The reaction was
quenched by the addition of saturated aqueous NaCl solution,
and the resulting suspension was filtered through Celite.
After the aqueous layer was extracted with three portions of
chloroform, the extracts were combined, dried over MgSO4, and
then concentrated under reduced pressure. Purification with
silica gel column chromatography by using hexane-dichlo-
romethane as an eluent gave 303 mg (60 % yield) of 7. The
3.29 (s, 4 H); 13C NMR (CDCl3) δ 24.7, 29.6, 31.9, 104.6, 112.4,
137.3; MS, m/z (% relative intensity) 312 (M+ + 2, 28), 310
(M+, 100), 282 (43), 236 (14), 162 (17), 88 (9); HRMS (EI) calcd
for C9H10S6 309.9107, measured 309.9104. Anal. Calcd for
C9H10S6: C, 34.80; H, 3.25. Found: C, 34.69; H, 3.03.
(Meth ylen ed ith io)d ih yd r otetr a th ia fu lva len e (14). The
same procedure as described above in A Typical Procedure was
employed except that (i) the aqueous layer was extracted with
dichloromethane, (ii) removal of the solvent was performed
below 40 °C, and (iii) purification with silica gel column
chromatography was carried out by using pentane and pen-
tane-dichloromethane as eluents: brown needles; mp 129 °C
dec from hexane-carbon disulfide; 1H NMR (CDCl3) δ 3.47 (s,
4 H), 4.91 (s, 2 H); 13C NMR (CDCl3) δ 40.0, 44.8, 117.2, 117.3,
119.5; MS, m/z (% relative intensity) 284 (M+ + 2, 26), 282
(M+, 100), 178 (58), 88 (54); HRMS (EI) calcd for C7H6S6
281.8794, measured 281.8795. Anal. Calcd for C7H6S6: C,
29.76; H, 2.14. Found: C, 29.77; H, 2.08.
(Vin ylen ed ith io)d ih yd r otetr a th ia fu lva len e (15). The
same procedure as described above in A Typical Procedure was
used except that purification with silica gel column chroma-

Synthesis of Unsymmetrical Tetrathiafulvalene Derivatives
J . Org. Chem., Vol. 61, No. 12, 1996 3993
tography was carried out by using hexane and hexane-
chloroform as eluents: orange needles; mp 184 °C dec from
ethanol-chloroform; 1H NMR (CDCl3) δ 3.46 (s, 4 H), 6.53 (s,
2 H); 13C NMR (CDCl3) δ 39.7, 114.7, 118.3, 121.3, 124.6; MS,
m/z (% relative intensity) 296 (M+ + 2, 27), 294 (M+, 100), 190
(44), 148 (23), 114 (18), 88 (15); HRMS (EI) calcd for C8H6S6
293.8794, measured 293.8793.
2-[4,5-(Vin yle n e d it h io)-1,3-d it h iol-2-ylid e n e ]-1,3-d i-
th ia n e (16). The same procedure as described in the proce-
dure for preparation of 15 was employed: yellow powder; mp
148-149 °C from ethanol-chloroform; 1H NMR (CDCl3) δ 2.18
(m, 2 H), 2.86 (m, 4 H), 6.55 (s, 2 H); 13C NMR (CDCl3) δ 24.7,
31.8, 106.5, 118.0, 124.3, 143.0; MS, m/z (% relative intensity)
310 (M+ + 2, 33), 308 (M+, 100), 234 (25), 202 (24), 162 (18),
88 (10); HRMS (EI) calcd for C9H8S6 307.8950, measured
307.8949; Anal. Calcd for C9H8S6: C, 35.03; H, 2.61. Found:
C, 34.88; H, 2.56.
Meth yl 4,5-d im eth yl-1,3-d ith iole-2-ca r boxyla te (22b):
orange oil; 1H NMR (CDCl3) δ 1.77 (s, 6 H), 3.71 (s, 3 H), 4.98
(s, 1 H); 13C NMR (CDCl3) δ 13.5, 47.6, 53.2, 119.5, 169.9; MS,
m/z (% relative intensity) 192 (M+ + 2, 8), 190 (M+, 80), 133
(29), 131 (100); HRMS (EI) calcd for C7H10O2S2 190.0122,
measured 190.0134.
Meth yl 4,5-dim eth yl-1,3-diselen ole-2-car boxylate (22c):
pale orange oil; 1H NMR (CDCl3) δ 1.87 (s, 6 H), 3.76 (s, 3 H),
5.15 (s, 3 H); 13C NMR (CDCl3) δ 15.9, 26.6, 53.5, 122.9, 171.7;
MS, m/z (% relative intensity) 288 (M+ + 4, 20), 286 (M+ + 2,
65), 284 (M+, 57), 282 (M+ - 2, 34), 229 (31), 227 (100), 225
(87), 223 (51); HRMS (EI) calcd for C7H10O280Se2 285.9011,
measured 285.9022.
Meth yl 4,5-tr im eth ylen e-1,3-d iselen ole-2-ca r boxyla te
(22d ): brownish-yellow solid; mp 50-51 °C; 1H NMR (CDCl3)
δ 2.3-2.5 (m, 6 H), 3.76 (s, 3 H), 5.84 (s, 1 H); 13C NMR (CDCl3)
δ 28.9, 32.8, 38.9, 53.5, 133.8, 171.3; MS, m/z (% relative
intensity) 300 (M+ + 4, 15), 298 (M+ + 2, 39), 296 (M+, 31),
(M+ - 2, 18), 241 (30), 239 (100), 237 (91), 235 (54); HRMS
(EI) calcd for C8H10O280Se2 297.9011, measured 297.9021.
Meth yl 1,2,5-Th ia d ia zolo[3,4-d ]-1,3-d ith iole-2-ca r boxy-
la te (24). In a 200-mL flask with a septum inlet was placed
0.88 g (5.0 mmol) of 23, and this flask was cooled in a water
bath. A methanol solution of NaOMe (1 M × 10 mL, 10 mmol)
was added in one portion via a syringe, and the mixture was
stirred for 10 min. After removal of the water bath, a solution
of methyl dichloroacetate (0.52 mL, 5.0 mmol) in THF (50 mL)
was added dropwise for 30 min, and stirring was continued
for 3 days. The reaction was quenched by saturated aqueous
NH4Cl solution, and the usual workup was carried out.
Purification of the product with silica gel column chromatog-
raphy by using hexane-dichloromethane as an eluent gave
478 mg (44% yield) of 24: pale yellow plate: mp 82.5-83.0
°C from hexane-dichloromethane; 1H NMR (CDCl3) δ 3.83 (s,
3 H), 5.84 (s, 1 H); 13C NMR (CDCl3) δ 54.1, 55.2, 161.2, 168.1;
MS, m/z (% relative intensity) 222 (M+ + 2, 12), 220 (M+, 84),
163 (46), 161 (100); HRMS (EI) calcd for C5H4O2N2S3 219.9435,
measured 219.9437.
Th ien od ih yd r otetr a th ia fu lva len e (17): yellow powder;
mp 105.5-106 °C from hexane-dichloromethane; 1H NMR
(CDCl3) δ 3.49 (s, 4 H), 6.82 (s, 2 H); 13C NMR (CDCl3) δ 39.8,
111.6, 117.8, 118.9, 136.8; MS, m/z (% relative intensity) 264
(M+ + 2, 20), 262 (M+, 89), 234 (18), 202 (37), 158 (100). Anal.
Calcd for C8H6S5: C, 36.61; H, 2.30. Found: C, 36.63; H, 2.20.
Dim eth yld ih yd r od iselen a d ith ia fu lva len e (18): orange
powder; mp 155.5-156.0 °C from ethanol-chloroform; 1H
NMR (CDCl3) δ 1.97 (s, 6 H), 3.51 (s, 4 H); 13C NMR (CDCl3)
δ 16.0, 41.2, 99.8, 118.9, 126.1; MS, m/z (% relative intensity)
332 (M+ + 4, 36), 330 (M+ + 2, 100), 328 (M+, 86), 326 (M+
-
2, 50), 226 (33), 224 (29). Anal. Calcd for C8H10S2Se2: C,
29.27; H, 3.07. Found: C, 29.28; H, 2.86.
Tr im eth ylen edih ydr odiselen adith iafu lvalen e (19): pale
orange plate; mp 196 °C dec from ethanol-chloroform; 1H NMR
(CDCl3) δ 2.34 (quintet, J ) 7.3 Hz, 2 H), 2.56 (t, J ) 7.3 Hz,
4 H), 3.52 (s, 4 H); 13C NMR (CDCl3) δ 27.2, 33.1, 40.8, 107.7,
120.4, 135.1; MS, m/z (% relative intensity) 344 (M+ + 4, 47),
342 (M+ + 2, 100), 340 (M+, 87), 338 (M+ - 2, 60), 238 (26),
236 (20); Anal. Calcd for C9H10S2Se2: C, 31.77; H, 2.96.
Found: C, 31.89; H, 2.95.
Dim e t h yl(e t h yle n e d it h io)d ise le n a d it h ia fu lva le n e
(DMET, 25). To a solution of tin selenolate 3d (139 mg, 0.31
mmol) in dichloromethane (1 mL) was added at -78 °C a
hexane solution of Me3Al (1.02 M × 0.6 mL, 0.61 mmol), and
then a solution of ester 22a (76 mg, 0.30 mmol) in dichlo-
romethane (1 mL) was added. The mixture was allowed to
warm up to room temperature, and stirring was continued
overnight. The reaction was quenched by the addition of
saturated aqueous NaHCO3 solution at 0 °C, and the resulting
suspension was filtered through Celite. The aqueous layer was
extracted with three portions of chloroform. The extracts were
combined, dried over MgSO4, and then concentrated in vacuo.
Purification of the residue with silica gel column chromatog-
raphy by using hexane and hexane-chloroform as eluents gave
53 mg (43% yield) of 25: mp 195 °C dec from hexane-
chloroform; 1H NMR (CDCl3) δ 2.00 (s, 6 H), 3.28 (s, 4 H). Anal.
Calcd for C10H10S4Se2: C, 28.84; H, 2.42. Found: C, 28.96;
H, 2.35.
T r im e t h y le n e (e t h y le n e d it h io )d is e le n a d it h ia fu l-
va len e (TMET-STF , 26). To a solution of the crude tin
thiolate 2a (124 mg, 0.30 mmol) in dichloromethane (3 mL)
were successively added at -78 °C a hexane solution of Me3-
Al (1.02 M × 0.6 mL, 0.61 mmol) and a solution of ester 22d
(89 mg, 0.30 mmol) in dichloromethane (2 mL). The mixture
was warmed up to room temperature gradually, and stirring
was continued overnight. The same workup and purification
as described above gave 47 mg (37% yield) of 26: mp 198 °C
dec from hexane-chloroform; 1H NMR (CDCl3-CS2) δ 2.38
(quintet, J ) 7.3 Hz, 2 H), 2.60 (t, J ) 7.3 Hz, 4 H), 3.30 (s, 4
H). Anal. Calcd for C11H10S4Se2: C, 30.84; H, 2.35. Found:
C, 30.95 H, 2.44.
(Eth ylen ed ith io)d ih yd r od iselen a d ith ia fu lva len e (20).
The same procedure as described above in A Typical Procedure
was employed except that (i) the aqueous layer was extracted
with carbon disulfide and (ii) purification with silica gel column
chromatography was carried out by using hexane and hexane-
carbon disulfide as eluents: light-red needles; mp 201 °C dec
1
from ethanol-carbon disulfide; H NMR (CDCl3) δ 3.29 (s, 4
H), 3.52 (s, 4 H); 13C NMR (CDCl3) δ 31.1, 40.9, 97.6, 114.0,
125.6; MS, m/z (% relative intensity) 394 (M+ + 4, 42), 392
(M+ + 2, 100), 390 (M+, 85), 388 (M+ - 2, 48), 336 (22), 276
(28); HRMS (EI) calcd for C8H8S480Se2 391.7839, measured
391.7812. Anal. Calcd for C8H8S4Se2: C, 24.61; H, 2.07.
Found: C, 24.53; H, 2.00.
A Typ ica l P r oced u r e for P r ep a r a t ion of E st er s via
Tr a n sm eta la tion . Preparation of 22a from tin thiolate 3a
is representative. In a 200-mL flask with a septum inlet were
placed 5.0 mmol (based on 2a ) of the crude tin thiolate 3a and
50 mL of THF, and the mixture was cooled to -78 °C.
A
hexane solution of nBuLi (1.61 M × 6.2 mL, 10 mmol) was
added dropwise for 10 min via a syringe, and stirring was
continued for 30 min at that temperature. After a solution of
methyl dichloroacetate (0.52 mL, 5.0 mmol) in THF (25 mL)
was added dropwise for 30 min, the reaction mixture was
allowed to warm to 0 °C, and the reaction was quenched by
saturated aqueous NH4Cl solution. The aqueous layer was
extracted with three portions of dichloromethane. The extracts
were combined, dried over MgSO4, and then concentrated in
vacuo. Chromatography of the residue on silica gel by using
hexane followed by hexane-dichloromethane as eluents gave
446 mg (35% yield based on 2a ) of 22a .
Meth yl 4,5-(eth ylen ed ith io)-1,3-d ith iole-2-ca r boxyla te
Tr im eth ylen e(th iadiazolo)diselen adith iafu lvalen e (27).
To an ice-cold solution of the crude tin selenolate 5 (2.7 mmol
based on 4) in dichloromethane (5.4 mL) was added dropwise
a hexane solution of Me3Al (1.02 M × 5.4 mL, 5.5 mmol), and
the mixture was stirred at room temperature for 1 h. After
the disappearance of 5 was monitored by an analytical TLC
(Merck 60F-254), a solution of ester 24 (0.59 g, 2.7 mmol) in
1
(22a ): pale reddish-orange oil; H NMR (CDCl3) δ 3.17 (m, 2
H), 3.27 (m, 2 H), 3.76 (s, 3 H), 5.11 (s, 1 H); 13C NMR (CDCl3)
δ 30.2, 48.8, 53.6, 111.7, 168.5; MS, m/z (% relative intensity)
254 (M+ + 2, 15), 252 (M+, 88), 195 (32), 193 (100), 167 (12),
165 (68); HRMS (EI) calcd for C7H8O2S4 251.9407, measured
251.9394.

3994 J . Org. Chem., Vol. 61, No. 12, 1996
Yamada et al.
dichloromethane (10.8 mL) was added at room temperature,
and stirring was continued at that temperature for 2 days.
The same workup and purification as described above gave
288 mg (27% yield) of 27: orange needles; mp 220 °C dec from
ethanol-chloroform; 1H NMR (CDCl3) δ 2.41 (quintet, J ) 7.3
Hz, 2 H), 2.62 (t, J ) 7.3 Hz, 4 H); MS, m/z (% relative
intensity) 400 (M+ + 4, 40), 398 (M+ + 2, 100), 396 (M+, 86),
394 (M+ - 2, 50), 282 (26), 238 (28); HRMS (EI) calcd for
C9H6N2S380Se2 397.8024, measured 397.8024.
2-(1′,3′-Dith iolan -2′-yliden e)-1,3-dith iolo[4,5-d]-1,3-dith i-
ol-2-on e (36c): light green powder; mp 212 °C dec from carbon
disulfide; 1H NMR (CDCl3-CS2) δ 3.53 (s, 4 H); MS, m/z (%
relative intensity) 298 (M+ + 2, 28), 296 (M+, 92), 270 (31),
268 (100), 148 (83); HRMS (EI) calcd for C7H4OS6 295.8586,
measured 295.8581.
2-(1′,3′-Dith ian -2′-yliden e)-1,3-dith iolo[4,5-d]-1,3-dith iol-
2-on e (36d ): pale brown powder; mp 185 °C dec from
ethanol-carbon disulfide; 1H NMR (CDCl3-CS2) δ 2.22 (m, 2
H), 2.92 (m, 4 H); MS, m/z (% relative intensity) 312 (M+ + 2,
33), 310 (M+, 100), 284 (25), 282 (77), 162 (36); HRMS (EI)
calcd for C8H6OS6 309.8743, measured 309.8753.
2-[4′,5′-(Eth ylen edith io)-1′,3′-dith iol-2′-yliden e]-1,3-dith i-
olo[4,5-d ]-1,3-d ith iol-2-on e (36e): orange needles; mp 245
°C dec from ethanol-carbon disulfide; 1H NMR (CDCl3-CS2)
δ 3.30 (s, 4 H); MS, m/z (% relative intensity) 386 (M+ + 2,
38), 384 (M+, 100), 358 (24), 356 (65), 192 (48); HRMS (EI)
calcd for C9H4OS8 383.8028, measured 383.8076.
Dim eth yl(th iadiazolo)diselen adith iafu lvalen e (28). The
same procedure as described above was used except that
reaction of tin selenolate 3d with Me3Al was carried out for 4
h. Purification followed by recrystallization from ethanol-
chloroform gave 28 in 14% yield: orange needles; mp 224-
1
225 °C from ethanol-chloroform; H NMR (CDCl3) δ 2.04 (s,
6 H); MS, m/z (% relative intensity) 388 (M+ + 4, 39), 386 (M+
+ 2, 100), 384 (M+, 86), 382 (M+ - 2, 50), 332 (18), 226 (42);
HRMS (EI) calcd for C8H6N2S380Se2 385.8024, measured
385.8022.
2-(4′,5′-Dim et h yl-1′,3′-d it h iol-2′-ylid en e)-1,3-d it h iolo-
[4,5-d ]-1,3-d ith iol-2-on e (36f): shiny brown powder; mp
189-190 °C from ethanol-carbon disulfide; 1H NMR (CDCl3-
2,2-Dib u t yl-2-st a n n a -1,3-d it h iolo[4,5-d ]-1,3-d it h iol-2-
on e (34). In a 200-mL flask with a septum inlet was placed
2.08 g (10 mmol) of thiapendione, and this flask was cooled in
a water bath. A methanol solution of NaOMe (1 M × 20 mL,
20 mmol) was added in one portion via a syringe, and the
mixture was stirred for 10 min. After the mixture was cooled
to -78 °C, a solution of Cl2SnBu2 (3.04 g, 10 mmol) in THF
(100 mL) was added dropwise for 50 min, and the reaction
mixture was allowed to warm to 0 °C. The reaction was
quenched by the addition of water, and the resulting mixture
was extracted with three portions of dichloromethane. The
extracts were combined, dried over MgSO4, and then concen-
trated in vacuo. Chromatography of the residue on silica gel
by using dichloromethane as an eluent gave 3.96 g (96% yield)
of 34: dark yellow plate; mp 97 °C dec from hexane-
dichloromethane; 1H-NMR (CDCl3) δ 0.95 (t, J ) 7.3 Hz, 6 H),
1.40 (m, 4 H), 1.78 (m, 8 H); 13C-NMR (CDCl3) δ 13.6, 24.0,
26.6, 27.8, 116.9, 193.0.
A Typ ica l P r oced u r e for Rea ction of 34 w ith Ester s.
Entry 3 in Table 2 is representative. In a 30-mL flask with a
septum inlet were placed 413 mg (1.0 mmol) of tin thiolate 34
and dichloromethane (5 mL), and the mixture was cooled to 0
°C. After a hexane solution of Me3Al (1.02 M × 2.0 mL, 2.0
mmol) was added, stirring was continued at room temperature
for 40 min, and then 0.28 mL (2.0 mmol) of ester 11a was
added via a syringe. The reaction mixture was stirred at room
temperature for 2 days, and the reaction was quenched by the
addition of saturated aqueous NaHCO3 solution at 0 °C. The
resulting suspension was filtered through Celite, and the
aqueous layer was extracted with three portions of carbon
disulfide. The extracts were combined, dried over MgSO4, and
then concentrated in vacuo. Purification of the product with
silica gel column chromatography by using hexane followed
by hexane-carbon disulfide as eluents gave 142 mg (48% yield)
of 36c.
2-Isop r op ylid en e-1,3-d it h iolo[4,5-d ]-1,3-d it h iol-2-on e
(36a ). The same procedure as described above in A Typical
Procedure was used except that (i) the aqueous layer was
extracted with chloroform and (ii) purification with silica gel
column chromatography was carried out by using hexane and
hexane-dichloromethane as eluents: brownish-yellow powder;
mp 180 °C dec from ethanol-chloroform: 1H NMR (CDCl3) δ
1.78 (s, 6 H); 13C NMR (CDCl3) δ 23.4, 111.9, 120.5, 122.8,
192.2; MS, m/z (% relative intensity) 236 (M+ + 2, 12), 234
(M+, 67), 208 (15), 206 (64), 86 (100); HRMS (EI) calcd for C7H6-
OS4 233.9302, measured 233.9295.
2-Cyclop en ta n ylid en e-1,3-d ith iolo[4,5-d ]-1,3-d ith iol-2-
on e (36b). The same procedure as described above was
employed except that purification with silica gel column
chromatography was performed by using hexane and hexane-
chloroform as eluents: brown needles; mp 170 °C dec from
ethanol-chloroform; 1H NMR (CDCl3) δ 1.81 (m, 4 H), 2.15
(m, 4 H); 13C NMR (CDCl3) δ 27.5, 34.4, 111.9, 115.5, 133.5,
192.2; MS, m/z (% relative intensity) 262 (M+ + 2, 13), 260
(M+, 42), 234 (10), 232 (57), 112 (100); HRMS (EI) calcd for
C9H8OS4 259.9458, measured 259.9458.
CS2) δ 2.02 (s, 6 H); MS, m/z (% relative intensity) 324 (M+
+
2, 16), 322 (M+, 57), 296 (29), 294 (100), 174 (59); calcd for
C9H6OS6 321.8743, measured 321.8746.
2-(4′,5′-Dim eth yl-1′,3′-d iselen ol-2′-ylid en e)-1,3-d ith iolo-
[4,5-d ]-1,3-d ith iol-2-on e (36g): dark brown powder; mp 222
1
°C dec from chloroform-carbon disulfide; H NMR (CDCl3-
CS2) δ 2.06 (s, 6 H); MS, m/z (% relative intensity) 420 (M+
+
4, 17), 418 (M+ + 2, 41), 416 (M+, 36), 414 (M+ - 2, 20), 390
(100), 388 (95); HRMS (EI) calcd for C9H6OS480Se2 417.7632,
measured 417.7604.
2-(4′,5′-Tr im eth ylen e-1′,3′-diselen ol-2′-yliden e)-1,3-dith i-
olo[4,5-d ]-1,3-d ith iol-2-on e (36h ): brownish-orange powder;
mp 198 °C dec from chloroform-carbon disulfide; 1H NMR
(CDCl3-CS2) δ 2.42 (m, 2 H), 2.64 (t, J ) 7.3 Hz, 4 H); MS,
m/z (% relative intensity) 432 (M+ + 4, 31), 430 (M+ + 2, 70),
428 (M+, 60), 414 (M+ - 2, 35), 402 (100), 400 (84); HRMS
(EI) calcd for C10H6OS480Se2 429.7632, measured 429.7620.
A Typ ica l P r oced u r e for Cr oss-Cou p lin g Rea ction s.
Reaction of 36c with 4,5-(ethylenedithio)-1,3-dithiole-2-thione
(1a ) is representative. In a 30-mL flask with a septum inlet
were placed 147 mg (0.5 mmol) of 36c, 224 mg (1.0 mmol) of
1a , toluene (5.0 mL), and trimethyl phosphite (5.0 mL). After
the mixture was refluxed with stirring for 2 h, the resulting
suspension was cooled to 0 °C and diluted with hexane. The
suspension was filtered through a filter paper, and the residue
was washed with hexane. The remaining solid was dissolved
in carbon disulfide, and the solution was concentrated under
reduced pressure. Purification of the residue with silica gel
column chromatography by using carbon disulfide as an eluent
gave 190 mg (80% yield) of 30b.
2-(Ben zo[d ]-1′,3′-d ith iol-2′-ylid en e)-5-isop r op ylid en e-
1,3,4,6-tetr a th ia p en ta len e (29a ): pale brown powder; mp
1
214 °C dec from ethanol-carbon disulfide; H NMR (CDCl3-
CS2) δ 1.75 (s, 6 H), 7.13 (m, 2 H), 7.24 (m, 2 H); MS, m/z (%
relative intensity) 372 (M+ + 2, 28), 370 (M+, 100), 208 (21),
196 (28), 152 (12); HRMS (EI) calcd for C14H10S6 369.9107,
measured 369.9099.
2-(B e n zo [d ]-1′,3′-d it h io l-2′-y lid e n e )-5-c y c lo p e n t a -
n ylid en e-1,3,4,6-tetr a th ia p en ta len e (29b): dark brown
powder; mp 210 °C dec from ethanol-carbon disulfide; 1H
NMR (CDCl3-CS2) δ 1.81 (br, 4 H), 2.13 (br, 4 H), 7.13 (m, 2
H), 7.24 (m, 2 H); MS, m/z (% relative intensity) 398 (M+ + 2,
28), 396 (M+, 100), 208 (10), 196 (30), 152 (15); HRMS (EI)
calcd for C16H12S6 395.9263, measured 395.9275.
2-[4′,5′-Bis(m eth ylth io)-1′,3′-d ith iol-2′-ylid en e]-5-(1′′,3′′-
dith iolan -2′′-yliden e)-1,3,4,6-tetr ath iapen talen e (30a): yel-
low powder; mp 187 °C dec from ethanol-chloroform; 1H NMR
(CDCl3-CS2) δ 2.42 (s, 6 H), 3.50 (s, 4 H); MS, m/z (% relative
intensity) 476 (M+ + 2, 65), 474 (M+, 100), 324 (23), 238 (21),
148 (26), 88 (29); HRMS (EI) calcd for C12H10S10 473.7990,
measured 473.7999; Anal. Calcd for C12H10S10: C, 30.35; H,
2.12. Found: C, 30.41; H, 2.08.
2-[4′,5′-(Eth ylen edith io)-1′,3′-dith iol-2′-yliden e]-5-(1′′,3′′-
dith iolan -2′′-yliden e)-1,3,4,6-tetr ath iapen talen e (30b): dark
red powder; mp 212 °C dec from chloroform-carbon disulfide;

Synthesis of Unsymmetrical Tetrathiafulvalene Derivatives
J . Org. Chem., Vol. 61, No. 12, 1996 3995
1H NMR (CDCl3-CS2) δ 3.30 (s, 4 H), 3.50 (s, 4 H); MS, m/z
(% relative intensity) 474 (M+ + 2, 45), 472 (M+, 100), 444 (63),
148 (57), 88 (44); HRMS (EI) calcd for C12H8S10 471.7833,
measured 471.7814; Anal. Calcd for C12H8S10: C, 30.48; H,
1.70. Found: C, 30.35; H, 1.60.
2-[4′,5′-(Meth ylen edith io)-1′,3′-dith iol-2′-yliden e]-5-(1′′,3′′-
d it h iola n -2′′-ylid en e)-1,3,4,6-t et r a t h ia p en t a len e (30c):
brown powder; mp 199 °C dec from carbon disulfide; 1H NMR
(400 MHz, CDCl3-CS2) δ 3.50 (s, 4 H), 4.96 (s, 2 H); MS, m/z
(% relative intensity) 460 (M+ + 2, 45), 458 (M+, 100), 338 (92),
234 (72), 148 (81); HRMS (EI) calcd for C11H6S10 457.7677,
measured 457.7677.
carbon disulfide; 1H NMR (CDCl3-CS2) δ 1.97 (s, 6 H), 6.89 (s,
2 H); MS, m/z (% relative intensity); 466 (M+ + 2, 42), 464
(M+, 100), 288 (15), 202 (28), 174 (95); HRMS (EI) calcd for
C14H8S9 463.8112, measured 463.8091.
2-(4′,5′-Dim eth yl-1′,3′-d iselen ol-2′-ylid en e)-5-[4′′,5′′-bis-
(m et h ylt h io)-1′′,3′′-d it h iol-2′′-ylid en e]-1,3,4,6-t et r a t h ia -
p en ta len e (33a ): reddish-brown powder; mp 205 °C dec from
ethanol-carbon disulfide; 1H NMR (CDCl3-CS2) δ 2.09 (s, 6
H), 2.43 (s, 6 H); MS, m/z (% relative intensity) 598 (M+ + 4,
59), 596 (M+ + 2, 100), 594 (M+, 91), 592 (M+ - 2, 50), 446
(13), 444 (11), 270 (27), 268 (23), 238 (27); HRMS (EI) calcd
for C14H12S880Se2 595.7035, measured 595.7020.
2-[4′,5′-Bis(m eth ylth io)-1′,3′-d ith iol-2′-ylid en e]-5-(1′′,3′′-
d ith ia n -2′′-ylid en e)-1,3,4,6-tetr a th ia p en ta len e (31a ): dark
orange powder; mp 205 °C dec from ethanol-carbon disulfide;
1H NMR (CDCl3-CS2) δ 2.20 (m, 2 H), 2.43 (s, 6 H), 2.89 (m,
4 H); MS, m/z (% relative intensity) 490 (M+ + 2, 63), 488 (M+,
100), 338 (22), 236 (38); HRMS (EI) calcd for C13H12S10
487.8146, measured 487.8122.
2-[4′,5′-(Eth ylen edith io)-1′,3′-dith iol-2′-yliden e]-5-(1′′,3′′-
d ith ia n -2′′-ylid en e)-1,3,4,6-tetr a th ia p en ta len e (31b): dark
orange powder; mp 230 °C dec from ethanol-carbon disulfide;
1H NMR (CDCl3-CS2) δ 2.21 (m, 2 H), 2.89 (m, 4 H), 3.31 (s, 4
H); MS, m/z (% relative intensity) 488 (M+ + 2, 47), 486 (M+,
100), 458 (64), 162 (63); HRMS (EI) calcd for C13H10S10
485.7990, measured 485.7983.
2-[4′,5′-(Meth ylen edith io)-1′,3′-dith iol-2′-yliden e]-5-(1′′,3′′-
dith ian -2′′-yliden e)-1,3,4,6-tetr ath iapen talen e (31c): brown
powder; mp 213 °C dec from ethanol-carbon disulfide; 1H
NMR (CDCl3-CS2) δ 2.20 (m, 2 H), 2.89 (m, 4 H), 4.97 (s, 2 H);
MS, m/z (% relative intensity) 474 (M+ + 2, 49), 472 (M+, 100),
352 (80), 278 (51), 222 (39), 162 (41); HRMS (EI) calcd for
C12H8S10 471.7833, measured 471.7834.
2-(Th ie n o[3,4-d ]-1′,3′-d it h iol-2′-ylid e n e )-5-(4′′,5′′-d i-
m eth yl-1′′,3′′-d ith iol-2′′-ylid en e)-1,3,4,6-tetr a th ia p en ta l-
en e (32): pale brown powder; mp 211 °C dec from ethanol-
2-(4′,5′-Tr im eth ylen e-1′,3′-d iselen ol-2′-ylid en e)-5-[4′′,5′′-
bis(m eth ylth io)-1′′,3′′-d ith iol-2′′-ylid en e]-1,3,4,6-tetr a th i-
a p en ta len e (33b): reddish-brown powder; mp 219.5 °C dec
1
from carbon disulfide; H NMR (CDCl3-CS2) δ 2.40 (quintet,
J ) 7.3 Hz, 2 H), 2.44 (s, 6 H), 2.62 (t, J ) 7.3 Hz, 4 H); MS,
m/z (% relative intensity) 610 (M+ + 4, 52), 608 (M+ + 2, 100),
606 (M+, 85), 604 (M+ - 2, 50), 458 (11), 456 (10), 282 (23),
280 (21), 238 (27); HRMS (EI) calcd for C15H12S880Se2 607.7035,
measured 607.7031. Anal. Calcd for C15H12S8Se2: C, 29.69;
H, 1.99. Found: C, 29.71; H, 1.92.
Ack n ow led gm en t. This work was supported by a
Grant-in-aid for Scientific Research (No. 06640752) from
the Ministry of Education, Science and Culture, J apan.
Su p p or tin g In for m a tion Ava ila ble: 1H NMR spectra of
compounds 2d , 9, 3a -d , 21, 5, 7, 10, 12, 15, 22a -d , 24, 27, 28,
34, 36a -h , 29a -b, 30c, 31a -c, 32, and 33a (36 pages). This
material is contained in libraries on microfiche, immediately
follows this article in the microfilm version of the journal, and
can be ordered from the ACS; see any current masthead page
for ordering information.
J O952255E