Synthesis of new chiral organosulfur donors with hydrogen bonding functionality and their first charge transfer salts

Article abstract of DOI:10.1016/j.tet.2013.07.089

The syntheses of a range of enantiopure organosulfur donors with hydrogen bonding groups are described including TTF related materials with two, four, six and eight hydroxyl groups and multiple stereogenic centres and a pair of chiral N-substituted BEDT-TTF acetamides. Three charge transfer salts of enantiopure poly-hydroxy-substituted donors are reported, including a 4:1 salt with the meso stereoisomer of the dinuclear [Fe₂(oxalate)₅] ^4- anion in which both cation and anion have chiral components linked together by hydrogen bonding, and a semiconducting salt with triiodide.

Full text of DOI:10.1016/j.tet.2013.07.089

Tetrahedron 69 (2013) 8738e8750
Contents lists available at ScienceDirect
Tetrahedron
journal homepage: www.elsevier.com/locate/tet
Synthesis of new chiral organosulfur donors with hydrogen bonding
functionality and their first charge transfer salts
Ismail Awheda a, Sara J. Krivickas a, Songjie Yang a, Lee Martin a, Milena A. Guziak a,
ꢀ ꢀ
,
b
a
a
b
Andrew C. Brooks a , Frederic Pelletier , Melvyn Le Kerneau , Peter Day ,
Peter N. Horton c, Hiroki Akutsu d, John D. Wallis a
,
*
a School of Science and Technology, Nottingham Trent University, Clifton Lane, Nottingham NG11 8NS, UK
b University College London, Department of Chemistry, 20 Gordon Street, London WC1H 0AJ, UK
c National Crystallography Service, Chemistry Department, University of Southampton, Highfield, Southampton SO17 1BJ, UK
d Graduate School of Material Science, University of Hyogo, Kamigori-cho, Ako-gun, Hyogo 678-1297, Japan
a r t i c l e i n f o
a b s t r a c t
Article history:
Received 7 March 2013
Received in revised form 13 July 2013
Accepted 30 July 2013
Available online 3 August 2013
The syntheses of a range of enantiopure organosulfur donors with hydrogen bonding groups are de-
scribed including TTF related materials with two, four, six and eight hydroxyl groups and multiple
stereogenic centres and a pair of chiral N-substituted BEDT-TTF acetamides. Three charge transfer salts of
enantiopure poly-hydroxy-substituted donors are reported, including a 4:1 salt with the meso stereo-
isomer of the dinuclear [Fe2(oxalate)5]4ꢀ anion in which both cation and anion have chiral components
linked together by hydrogen bonding, and a semiconducting salt with triiodide.
Keywords:
TTF
Ó 2013 Elsevier Ltd. All rights reserved.
Organosulfur donors
Hydrogen bonding
Chirality
1. Introduction
system as in 6, 715,16 as well as donors fused to a chiral pinene
system, e.g., 817 or incorporating a stereogenic axis from a 1-,10-
TTF 1 and BEDT-TTF 2 have been at the forefront for the prep-
aration of electrically conducting molecular systems, the former
providing the first example of an organic metal in its complex with
TCNQ,1 and the latter providing a large number of salts with varying
electronic properties, including superconductivity.2 Considerable
numbers of substituted derivatives of TTF and BEDT-TTF have been
reported,3,4 and the former especially have found potential appli-
cations as molecular switches,5,6 sensors,5,7 field effect transistors8
and molecular electronics9 as well as in the preparation of con-
ducting radical cation salts and fibres.10 Two recent research
themes in this area have been the installation of chirality into the
donor molecules and the attachment of groups with hydrogen
bonding potential. The former is of importance following the dis-
covery of magneto-chiral anisotropy in chiral conducting systems.11
The latter is important since hydrogen bonding with the anion in
a salt, or between donors, can offer new organisations in the
crystalline state.12 A range of enantiopure donors related to BEDT-
TTF have been reported, including several with a stereogenic cen-
tre at a ring C or S atom, e.g., 3e5,13,14 or external to the donor
binaphthyl system.18 Examples of the latter have been investigated
as redox sensitive chiroptical switches.19 Several simple TTF de-
rivatives with chiral side chains have also been reported, e.g., 9,1020
while Kato has combined 11 with an aromatic liquid crystal and an
electron acceptor to provide fibrous conducting materials.21 Prog-
ress in these areas has been reviewed.22 A few enantiopure donors
with hydrogen bonding functionality have been reported, e.g.,
BEDT-TTF derivatives 12e14,4b,23 as well as a series of peptide de-
rivatives and a D
-glucose derived material.24 Here we report the
preparation of new donors 15e22, which are both enantiopure and
include hydroxyl or amide groups capable of forming hydrogen
bonds, as well as progress towards making trans-BEDT-TTF diacid
23 as a racemate.
2. Results and discussion
2.1. Synthesis of chiral TTF-related polyols 15e20
As a first step to provide donors with both chirality and hy-
drogen bonding potential, two TTF derivatives with 2-
hydroxypropylthio side-chains, which had a hydroxyl group at
a stereogenic centre were targeted (Scheme 1). Reaction of
* Corresponding author. E-mail address: john.wallis@ntu.ac.uk (J.D. Wallis).
0040-4020/$ e see front matter Ó 2013 Elsevier Ltd. All rights reserved.
http://dx.doi.org/10.1016/j.tet.2013.07.089

I. Awheda et al. / Tetrahedron 69 (2013) 8738e8750
8739
Scheme 1.
unsubstituted thione 29 to give the disubstituted donor 30 in 43%
yield, which was subsequently hydrolysed to the diol 16 in 94%
yield (Scheme 2). The R,R enantiomer of 16 was prepared in a sim-
ilar way starting from (R)-methyloxirane. The attempted synthesis
of the meso-(R,S)-isomer of 16 from rac-methyloxirane led to
unseparable mixtures of meso and racemic (R,R) compounds at each
step. The racemate is most easily made by mixing equimolar
amounts of the two enantiomers. The crystal structure of donor 15
(Fig. 1) shows that one pair of chains form an internal hydrogen
bond while both make further intermolecular interactions so that
the donors and side-chains are more or less segregated in the
crystal packing.26
Scheme 2.
Introduction of hydroxyl groups on to the terminal methyl
groups of these two would provide donors 17 and 18 with addi-
tional sites for hydrogen bonding or for extension of the side chains.
The synthesis of these materials (Scheme 3) was achieved by re-
action of the dithiolate 24 with 2 equiv of the triflate of (S)-1,2-
isopropylidene-glycerol to give the thione 31 in 90% yield. Nei-
ther the corresponding mesylate nor tosylate were effective for this
reaction. The symmetrical donor 17 was then prepared in three
steps by conversion of thione 31 to the oxo compound 32, homo-
coupling in triethyl phosphite to give the tetra(ketal) donor 33 in
51% yield and then almost quantitative deprotection of the diol
dithiolate 2425 with 2 equiv of (S)-methyloxirane gave the thione
25 containing two chiral 2-hydroxypropylthio side-chains in 51%
yield. The synthesis was continued by protection of the hydroxyl
groups by acetylation to give 26 and exchange of the thione sulfur
for oxygen using mercuric acetate to give the oxo compound 27 in
71% yield from thione 25. Homo-coupling of 27 in refluxing tri-
methyl phosphite for 24 h gave the chiral O-protected donor 28 in
31% yield, which was then hydrolysed to the chiral tetrol 15 in 91%
yield. The chiral oxo compound 27 was also cross-coupled with the

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To provide a donor with different chirally disposed hydrogen
bonding functionality at either end, the donor 19 was prepared,
which at one end had two (R)-2-hydroxypropylthio side chains and
at the other end two (R)-2,3-dihydroxypropylthio side chains
(Scheme 5). This was achieved by reacting the R,R-enantiomer of
bis(acetoxy) thione 26 with the bis ketal-protected oxo compound
32 in triethyl phosphite to give the O-protected hexol 35 in 30%
yield after chromatography to separate from homo-coupled spe-
cies. Removal of the acetyl protecting groups with aqueous potas-
sium carbonate gave the dihydroxy donor 36, and the ketal groups
were hydrolysed by subsequent treatment with HCl in THF to yield
the unsymmetrical chiral hexol donor 18 with two different pairs of
hydroxyl substituted stereogenic centres.
To prepare a donor with one chiral hydrogen bonding side
chain at each end, the approach of Becher to make bis(pyrrolo)
TTFs27,28 was taken, an approach, which has already yielded the
chiral donor 7.16 Thus the donor 20, a bis(pyrrolo)tetrathiafulva-
lene bearing 2S-2-(1-hydroxy)propyl substituents attached to each
nitrogen atom, was chosen as a target (Scheme 6). The synthesis
started from (S)-(þ)-2-amino-1-propanol, by O-protection with
a tert-butyldiphenylsilyl group to give amine 37,29 which was
reacted with bis(bromomethyl)-1,3-dithiolethione28 in the pres-
ence of sodium carbonate and tetrabutylammonium iodide to give
the dihydropyrrole derivative 38, which was directly oxidised with
DDQ in benzene at ca. ꢀ10 ꢁC to give the dithiolo(4,5-c)pyrrole
thione 39 in 53% overall yield after chromatography. Prolonged
reflux of thione 39 with freshly distilled trimethyl phosphite gave
the corresponding bis(pyrrolo)tetrathiafulvalene 40 in 32% yield.
Deprotection of the hydroxyl groups was carried out using tetra-
butylammonium fluoride in THF at room temperature to give the
desired chiral donor 20 functionalised with two hydroxyl groups
in 50% yield.
Fig. 1. Molecular structure of 15, showing the hydrogen bond between two side chains.
2.2. Synthesis of enantiopure amides 21 and 22
There is only one monosubstituted BEDT-TTF, which has been
prepared as a pure enantiomer, the hydroxymethyl derivative, but
the route is eight steps from (S)-1,2-isopropylideneglycerol. With
a view to resolving the chirality at the stereogenic centre on
a BEDT-TTF derivative in a shorter sequence we have taken an
approach to deliberately prepare diastereomers, which can then
be separated, in this case by modification of our synthesis of the
racemic BEDT-TTF derivatives bearing a functionalised acetamide
side chain (eCH2CONHR).30 Trithione 4125 was reacted with
vinylacetic acid to give the bicyclic carboxylic acid 42, which was
then converted to two diastereoisomeric amides 43 and 44 by
formation of the mixed anhydride with ethyl chloroformate fol-
Scheme 3.
groupings using HCl in THF. The unsymmetrical donor 18 was
prepared by cross-coupling of the oxo compound 32 with the thi-
one 29 to give the donor 34 in 60% yield after chromatography,
which was deprotected to give the tetrol 18 in 95% yield (Scheme 4).
lowed by reaction with the enantiopure amine R-a-phenylethyl-
amine (Schemes 7). The two isomeric amides were separated by
chromatography and obtained in similar yields of ca. 28%, and the
structure of 44 was confirmed by X-ray crystallography to have the
S configuration at 5-C (Fig. 2). The main difference in their 1H NMR
spectra is between the signals from the side chain methylene
groups, which in 43 appears as a doublet at
d: 2.71 ppm, but in 44
appears as two doublet doublets at : 2.63 and 2.71 ppm. Both
d
thiones were cross-coupled with the unsubstituted oxo compound
45 in triethyl phosphite at 90 ꢁC to give the corresponding chiral
donors 21 and 22 in 31 and 46% yields, respectively. Attempts to
convert these new donors to the enantiomers of primary amide
BEDT-TTFeCH2CONH2 have been unsuccessful. However, these
donors are likely to be better substrates for investigating the in-
fluence of chirality on conductivity since the two enantiomers of
the primary amide can adopt similar shapes by the substituted
dithiin ring adopting the particular envelope conformation, which
places the side chain in a pseudo-equatorial position.
Scheme 4.

I. Awheda et al. / Tetrahedron 69 (2013) 8738e8750
8741
Scheme 5.
Scheme 6.
2.3. Synthesis of the racemic trans-diacid 23
attempted the synthesis of the racemate of bis-acid 23. Reaction of
dimethyl E-hex-3-en-1,5-dioate with the trithione 41 in refluxing
toluene gave the thione 46 with trans oriented side chains in 76%
yield. Reaction of the thione 46 with mercuric acetate gave the oxo
compound 47 in 94% yield, the cross-coupling of which with the
unsubstituted thione 29 gave the trans disubstituted donor 48 in
55% yield (Schemes 8). (Homo-coupling of 47 in trimethyl phos-
phite at 120 ꢁC gave the tetrasubstituted BEDT-TTF in 81% yield as
a mixture of a racemate and a meso compound.) Hydrolysis of the
diester 48 with potassium hydrogen carbonate in a water/meth-
anol/THF mixture followed by acidification give a solid the com-
position of which corresponds to a 1:1 mixture of the diacid 23
and its monopotassium salt.
Carboxylic acid groups are also potential hydrogen bonding
centres, as well as precursors of other functionalities. The only
such BEDT-TTF derivative reported is the mono eCH2CO2H de-
rivative, which has very limited solubility in typical organic sol-
vents. So we examined routes to an enantiomer of the trans bis-
acid
23.
Attempted
synthesis
from
dimethyl
3,4-
dihydroxyhexandioate failed when the derived cyclic sulfate es-
ter could not be cyclised with the dithiolate 24. The enantiomers
of such trans-disubstituted BEDT-TTFs have been difficult to pre-
pare, for example, trans-BEDT-TTFebis(methanol) was only pre-
pared in enantiopure form by chiral chromatography.13 We thus

8742
I. Awheda et al. / Tetrahedron 69 (2013) 8738e8750
Scheme 7.
Fig. 2. Molecular structure of diastereomer 44 with (S) stereochemistry at 5-C on the
dithiin ring.
Scheme 9.
Scheme 8.
To extend this chemistry, oxo compound 47 was cross-coupled
with thione 49, the adduct of norbornene and trithione 41
(Schemes 9). The latter is formed very readily and exclusively as the
exo-adduct in 95% yield, and its stereochemistry was confirmed by
X-ray crystallography.26 The cross-coupled product was produced
as a 1:1 mixture of two diastereomers 50 and 51.
17e19, are notably higher, possibly a reflection of a non-reversible
interaction with the electrode. Here we report the first results for
preparing charge transfer materials from enantiopure donors 16
and 18. Diol 16 forms a salt with the Fe(III)2(oxalate)5 tetraanion by
electrocrystallisation with the ammonium salt of racemic iron(III)
tris(oxalate) and a molecular complex with tetrafluoro-TCNQ.
Tetrol 18 forms a 1:1 salt with triiodide. In the crystals of the ox-
alate salt (monoclinic, P21) the asymmetric unit contains four donor
2.4. Charge transfer salts
4ꢀ
molecules and one FeðIIIÞ2ðoxalateÞ5 species in which one oxa-
The oxidation potentials of the novel donors show two oxidation
potentials similar to those of BEDT-TTF and tetra(methylthio)TTF
(Table 1), though the donors with side-chains containing diols,
late bridges between the two iron atoms, which thus retain co-
ordination numbers of six (Fig. 3). The chiralities at the two metal
centres in the anion are opposite (D and L), nevertheless this is the

I. Awheda et al. / Tetrahedron 69 (2013) 8738e8750
8743
Table 1
Cyclic voltammetry data for electron donorsa
Donor
E1 (V)
E2 (V)
15
16
0.50
0.48
0.68
0.71
0.69
0.56
0.52
0.59
0.59
0.61
0.58
0.58
0.57
0.76
0.80
0.83
0.85
0.83
0.95
0.91
0.89
0.92
0.92
0.86
0.97
0.96
17b
18b
19b
21
22
33
34
35
36
48
50/51
Fig. 4. Hydrogen bonding between the TCNQ-F4 molecules in one layer and molecules
of donor 16 in adjacent layers, showing pairing of donor molecules. Donor pairs in the
central layer are omitted for clarity.
a
Measured relative to Ag/AgCl at a platinum electrode in dichloromethane con-
taining 0.1 M n-Bu4NPF6 as charge carrier and using a 100 mV sꢀ1 scan.
b
THF used as solvent.
Although there is no stacking between the donor pairs, there are
two S/S side to side contacts between donor pairs
ꢁ
(3.545e3.579 A). The material is an insulator: multiple crystals
measured showed room temperature resistances higher than the
measurement upper limit of the equipment (>1ꢂ107 U).
Diffusion of iodine into a DꢀCM solution of chiral tetrol 18 gave
crystals of a 1:1 salt with I3 the structure of which was de-
termined by X-ray crystallography at 150 K. Donor monocations are
organised in ‘face-to-face pairs’ with side chains at opposite ends of
the pair and directed away from the other donor (Fig. 5). Triiodides
are organised in ‘end to end’ linear pairs with the I/I contact be-
ꢁ
tween them being one of the shortest reported (3.422 A). There are
ꢁ
six short S/S contacts (3.365e3.480 A) within the pair of donors,
and two sets of intermolecular hydrogen bonds: one between
secondary hydroxyl groups, and a roughly square array involving
four primary hydroxyl groups with a 1:1 disorder in the positions of
the hydrogen atoms around the square of oxygen atoms, with ei-
ther arrangement breaking the symmetry of the twofold axis,
which cuts the square. The salt is semiconducting with a room
temperature resistivity of 3.61 U cm with an activation energy of
22.5 meV and show hysteresis in the range 60e250 K on cooling
and rewarming (Fig. 6). This may be related to the disordered hy-
drogen bonding square arrangement, which may prefer just one of
the two possible arrangements at low temperature (<60 K), and
this is maintained on warming until ca. 250 K.
Fig. 3. Crystal packing arrangement of (16)4Fe2(oxalate)5 viewed along b, perpendic-
ular to the successive layers of anions and donor cations.
first report of a charge transfer salt with a source of chirality in both
the donor and the anion components. Charge transfer salts of this
anion with TTF and BEDT-TTF have been reported.31 The accuracy of
the bond lengths is not sufficient for application of the empirical
method for estimating each donor’s oxidation state to determine
whether the net charge of þ4 is equally distributed or not.32 The
crystal structure contains alternate layers of donors and anions,
with donors stacking within the layer. The eight terminal O atoms
of the anion form seven hydrogen bonds to hydroxyl groups be-
longing to donor molecules, and there is just one crystallographi-
cally unique hydrogen bond between donor molecules, and it
bridges between stacks. The bridging oxalate residue is not in-
volved in any hydrogen bonding. Reproducible two probe re-
sistivity measurements were not possible due to the fragility of the
tiny crystals.
3. Conclusion
A new range of symmetrically and unsymmetrically substituted
enantiopure donors with hydrogen bonding potential are now
available. The challenge now is to prepare conducting systems from
them and see how their chirality moderates their electromagnetic
properties by a comparison of the properties of products prepared
from opposite enantiomers. Electrocrystallisation studies and dif-
fusion experiments with electron deficient species are underway to
build on the salts prepared here in which hydrogen bonding plays
an important role in their physical properties.
The crystal structure of the 1:1 complex with TCNQ-F4 is quite
different (Fig. 4). The donors and acceptors are both packed in face-
to-face pairs with one pair of donors and one pair of acceptors in
the unit cell (triclinic, P1). The donor pairs are packed head to tail
with four short S/S contacts between sulfur atoms of the opposing
4. Experimental
4.1. General
ꢁ
TTF units (3.339e3.354 A), and the average bond lengths in the TTF
NMR spectra were measured on a JEOL ECLIPSE 400 spec-
trometer at 400 MHz for 1H and at 100.6 MHz for 13C using CDCl3
as solvent and tetramethylsilane (TMS) as standard unless other-
wise stated, and measured in parts per million downfield from
TMS with coupling constants reported in hertz. IR spectra were
recorded on PerkineElmer Spectrum 100 FT-IR Spectrometer
cores indicate that the donor is a monocation.32 The material is thus
best considered as a salt. The pairs of donors and acceptors form
layers in the b,aec plane, with the best planes of the TTF cores of
the donors and the TCNQ-F4 acceptors lying at ca. 65ꢁ to each other.
There are OeH/F hydrogen bonds between the layers (Fig. 4).

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I. Awheda et al. / Tetrahedron 69 (2013) 8738e8750
using an ATR window, and are reported in cmꢀ1. Raman mea-
surements were made on a Foster and Freeman Foram 685-2
spectrometer, with excitation at 685 nm and are reported in cmꢀ1
.
Solid-state UV/vis spectra was measured using a JASCO V-670 in-
strument. Optical rotation data were measured on a PerkineElmer
241 polarimeter at the sodium D-line. Mass spectra were recorded
at the EPSRC Mass Spectrometry Centre at the University of
Swansea. Chemical analysis data were obtained from Mr Stephen
Boyer, London Metropolitan University. X-ray diffraction datasets
were measured by the EPSRC National Crystallography Service at
Southampton University. Flash chromatography was performed on
40e63 silica gel (Merck).
4.2. Bis((20S)-20-hydroxylpropylthio)-1,3-dithiole-2-thione 25
A solution of disodium dithiolate 24 in dry methanol (300 ml),
prepared in situ from 4,5-bis(benzoylthio)-1,3-dithiol-2-thione
(17.5 g, 43.0 mmol) and sodium methoxide (4.66 g, 86 mmol) un-
der a nitrogen atmosphere,25 was treated with (S)-(ꢀ)-propylene
oxide (5.0 g, 86.0 mmol) at room temperature. The deep purple
solution turned orange-red over several minutes, and the mixture
stirred at room temperature for 5 h. Acetic acid (10 ml) was added.
After stirring for 1 h, the reaction mixture was concentrated in
vacuo, the methyl benzoate removed by Kugelrohr distillation, and
the residue was purified by flash chromatography (SiO2, eluting
with cyclohexane/ethyl acetate 2:1) to yield 25 (6.90 g, 51.0%) as
a red-brown oil; Rf (cyclohexane/ethyl acetate 2:1) 0.26; dH
(400 MHz, CDCl3) 3.90 (2H, m, 2ꢂ CHOH), 3.23 (2H, br, 2ꢂ OH), 2.99
(2H, dd, J 3.6, 13.8 Hz, 2ꢂ CHaS), 2.78 (2H, dd, J 8.4, 13.8 Hz, 2ꢂ
CHbS), 1.24 (6H, d, J 6.2 Hz, 2ꢂ CH3); dC (100.6 MHz, CDCl3) 210.6
(C]S), 136.6 (4-,5-C), 66.1 (2ꢂ CHOH), 45.4 (2ꢂ CH2S), 22.0 (2ꢂ
CH3); nmax: 3342, 2967, 2919, 1724, 1455, 1399, 1372, 1240, 1188,
1123, 1058, 1035, 934, 892, 816, 516, 451; m/z: (ES) 314 [M]þ; found
293
C, 34.50; H, 4.55%, C9H14O2S5 requires C, 34.37; H, 4.49%; [a]
D
þ61.7 (c 1.8, CHCl3).
4.3. Bis((20S)-20-acetoxypropylthio)-1,3-dithiole-2-thione 26
Acetic anhydride (5.0 ml, 52.9 mmol) was added to a solution of
thione 25 (6.48 g, 20.6 mmol) in pyridine (70 ml) at 0 ꢁC and then
stirred overnight at room temperature. Water (300 ml) was added
and the mixture extracted with CH2Cl2 (3ꢂ100 ml). The organic
solution was washed consecutively with 0.5 M HCl solution
(3ꢂ100 ml) and H2O (100 ml), dried (MgSO4) and evaporated. The
residue was purified by flash chromatography (SiO2, eluting with
cyclohexane/ethyl acetate 4:1) to yield the protected thione 26
(6.16 g, 75.0%) as an orange-brown oil; Rf (cyclohexane/ethyl ace-
tate 4:1) 0.30; dH (400 MHz, CDCl3) 4.99 (2H, m, 2ꢂ CHOAc), 2.99
(4H, d, J 5.8 Hz, 2ꢂ CH2S), 1.98 (6H, s, 2ꢂ CH3CO), 1.29 (6H,
d, J 6.4 Hz, 2ꢂ CH3); dC (100.6 MHz, CDCl3) 210.2 (C]S), 169.9 (2ꢂ
C]O), 136.2 (4-,5-C), 69.0 (2ꢂ CHOAc), 41.3 (2ꢂ CH2S), 20.9 (2ꢂ
CH3CO), 19.0 (2ꢂ CH3); nmax: 2979, 2932, 1733, 1456, 1370, 1228,
1128, 1061, 1035, 955, 888, 632, 606, 516, 451, 412; m/z: (ES) 398
[M]þ; found C, 39.25; H, 4.58%, C13H18O4S5 requires C, 39.17; H,
Fig. 5. Crystal packing arrangement of 18$I3 showing the end to end triiodide pair and
donor cation pairs (top), and four primary hydroxyl groups hydrogen bonding together
in a square formation, in which just one of two sets of hydrogen atom positions is
shown (below).
4.55%; [
a
]
293 þ45 (c 1.20, CHCl3).
D
4.4. Bis((20S)-20-acetoxypropylthio)-1,3-dithiole-2-one 27,
(Method A)
To a solution of the thione 26 (5.54 g, 13.9 mmol) in chloroform
(130 ml) was added mercuric acetate (6.70 g, 21.0 mmol). After
stirring for 2 h, the reaction mixture was filtered and the solid
residue washed with chloroform. The combined filtrates were
washed with sodium hydrogen carbonate solution and then water,
dried over magnesium sulfate and concentrated in vacuo. The
residue was purified by flash chromatography (SiO2, eluting with
Fig. 6. Plot of ln(Resistivity) versus 1/T for 18$I3 showing hysteresis between 60 and
250 K.

I. Awheda et al. / Tetrahedron 69 (2013) 8738e8750
8745
cyclohexane/DCM 3:1) to yield the oxo compound 27 as a brown
4.8. Bis((2S)-2-hydroxylpropylthio)(ethylenedithio)TTF 16
oil (5.07 g, 95.4%); Rf (cyclohexane/DCM 3:1) 0.41; dH (400 MHz,
CDCl3) 4.97 (2H, m, 2ꢂ CHOAc), 2.94 (4H, d, J 5.8 Hz, 2ꢂ CH2S), 1.96
(6H, s, 2ꢂ CH3CO), 1.27 (6H, d, J 6.3 Hz, 2ꢂ CH3); dC (100.6 MHz,
CDCl3) 188.7 (C]O), 169.9 (2ꢂ COCH3), 127.3 (4-,5-C), 69.1 (2ꢂ
An aqueous solution (30 ml) of potassium carbonate (1.70 g,
12.3 mmol) was added to a solution of the di-acetate 30 (1.07 g,
1.91 mmol) in methanol (240 ml) and THF (20 ml). After stirring
overnight, the reaction mixture was concentrated and the solid was
collected and washed with water to yield the chiral diol 16 as
a yellow solid (855 mg, 94.1%); mp 108e110 ꢁC; Rf (ethyl acetate)
0.41; dH (400 MHz, CDCl3) 3.79 (2H, m, 2ꢂ CHOH), 3.23 (4H, s, 50-,60-
H2), 2.97 (2H, dd, J 3.3, 13.8 Hz, 2ꢂ CHaS), 2.84 (2H, br s, 2ꢂ OH),
2.62 (2H, dd, J 9.0, 13.8 Hz, 2ꢂ CHbS), 1.20 (6H, d, J 6.3 Hz, 2ꢂ CH3);
dC (100.6 MHz, CDCl3) 128.3 (4-,5-C), 113.8 (3a0-,7a0-C), 112.3 &
109.7 (2-,20-C), 65.9 (2ꢂ CHOH), 45.3 (2ꢂ CH2S), 30.2 (50-,60-C), 21.8
(2ꢂ CH3); nmax: 3306, 2965, 2916, 1451, 1405, 1371, 1343, 1282, 1254,
1239, 1126, 1068, 1038, 1003, 934, 915, 878, 863, 812, 770, 720, 684,
472, 454, 442; m/z: (EI) 474 [M]þ; found C, 35.51; H, 3.84%,
CHOAc), 41.2 (2ꢂ CH2S), 20.9 (2ꢂ CH3CO), 18.9 (2ꢂ CH3); nmax
:
2980, 2933, 1734, 1667, 1613, 1448, 1370, 1229, 1128, 1092, 1037,
955, 883, 739, 632, 607, 551, 461; m/z: (ES) 382 [M]þ; found C,
40.81; H, 4.68%, C13H18O5S4 requires C, 40.82; H, 4.74%; [
(c 1.80, CHCl3).
a
]
293 þ1.0
D
4.5. Tetrakis((2S)-2-acetoxypropylthio)TTF 28, (Method B)
A mixture of oxo compound 27 (3.30 g, 8.62 mmol) and freshly
distilled trimethyl phosphite (60 ml) was heated to reflux for 24 h.
The solvent was evaporated to dryness, and the residue was sub-
jected to flash chromatography (SiO2, eluting with cyclohexane/
ethyl acetate 4:1) to yield the TTF derivative 28 as an orange oil
(1.95 g, 30.9%); Rf (cyclohexane/ethyl acetate 4:1) 0.14; dH
(400 MHz, CDCl3) 5.01 (4H, m, 4ꢂ CHOAc), 2.97 (8H, d, J 5.7 Hz, 4ꢂ
CH2S), 2.03 (12H, s, 4ꢂ CH3CO), 1.32 (12H, d, J 6.4 Hz, 4ꢂ CH3); dC
(100.6 MHz, CDCl3) 170.1 (4ꢂ C]O), 127.9 (4-,40-,5-,50-C), 110.6 (2-
,20-C), 69.4 (4ꢂ CHOAc), 40.9 (4ꢂ CH2S), 21.1 (4ꢂ CH3CO), 19.0 (4ꢂ
CH3); nmax: 2979, 2932, 1733,1447, 1369, 1227, 1128, 1091, 1034, 954,
C14H18O2S8 requires C, 35.42; H, 3.82%; [
a
]
D
293 þ146 (c 0.42, CHCl3).
4.9. Synthesis of bis((2R)-2-
hydroxylpropylthio)(ethylenedithio)TTF
This followed the procedure for the S-enantiomer but starting
from (R)-(þ)-propylene oxide to give a final product with optical
rotation [
a]
293 ꢀ148 (c 0.42, CHCl3).
D
890, 856, 772, 632, 606; m/z: (EI) 732 [M]þ; found C, 42.69; H,
293
4.90%, C26H36O8S8 requires C, 42.60; H, 4.95%; [
CHCl3).
a
]
þ60.2 (c 1.5,
D
4.10. Preparation of 16$Fe2(oxalate)5
(NH4)3[Fe(C2O4)3]$3H2O (120 mg) and 18-crown-6 (200 mg) in
a 1:1 mixture of dichloromethane and acetonitrile (40 ml) were
stirred for 6 h and filtered into both sides of an electrochemical cell,
which contained donor 16 (10 mg) in the anode compartment. On
4.6. Tetrakis((2S)-2-hydroxylpropylthio)TTF 15
An aqueous solution (60 ml) of potassium carbonate (3.20 g,
23.2 mmol) was added to a solution of the tetra-acetate 28 (1.95 g,
2.66 mmol) in methanol (240 ml). After stirring overnight, the re-
action mixture was concentrated and the solid was collected and
washed with water to yield the chiral tetrol 15 as an orange solid
(1.37 g, 91.2%); mp 91e93 ꢁC; Rf (ethyl acetate/methanol 10:1) 0.47;
dH (400 MHz, CDCl3) 3.83 (4H, m, 4ꢂ CHOH), 2.98 (4H, dd, J 3.1,
13.7 Hz, 4ꢂ CHaS), 2.95 (4H, br, d, J 3.0 Hz, 4ꢂ OH), 2.65 (4H, dd, J
8.9,13.7 Hz, 4ꢂ CHbS), 1.22 (12H, d, J 6.3 Hz, 4ꢂ CH3); dC (100.6 MHz,
CDCl3) 128.3 (4-,40-,5-,50-C), 110.7 (2-,20-C), 66.0 (4ꢂ CHOH), 45.2
(4ꢂ CH2S), 21.8 (4ꢂ CH3); nmax: 3320, 2965, 2915, 1455, 1396, 1377,
1294,1273,1245,1124,1072,1034, 932, 892, 875, 865, 823, 770, 725,
applying a current of 1.0 mA across the cell, crystals began to grow in
the first week and were harvested after 21 days. A large quantity of
black plates of (16)4[Fe2(C2O4)5] were obtained and were found to
be suitable for X-ray structure determination.
4.11. Preparation of complex of 16 with TCNQ-F4
TCNQ-F4: a solution of TCNQ-F4 (7 mg) in acetonitrile (3 ml) was
gently layered over a solution of diol 16 (12 mg) in chloroform
(3 ml) and left to slowly evaporate giving black crystals of a 1:1
complex whose composition was determined by X-ray
crystallography.
568, 465, 419, 410; m/z: (EI) 564 [M]þ; found C, 38.23; H, 5.04%,
293
C18H28O4S8 requires C, 38.27; H, 5.00%; [
CHCl3).
a]
þ212.5 (c 0.24,
D
4.12. 4,5-Bis(((40R)-20,20-dimethyl-10,30-dioxolan-40-yl)methyl-
4.7. Bis((2S)-2-acetoxypropylthio)(ethylenedithio)TTF 30,
thio)-1,3-dithiole-2-thione 31
(Method C)
A solution of disodium dithiolate 24 in dry methanol (10 ml),
prepared in situ from 4,5-bis(benzoylthio)-1,3-dithiol-2-thione
(410 mg, 1.0 mmol) and sodium methoxide (0.48 ml, solution 25%
wt, 2.0 mmol) under a nitrogen atmosphere,25 was treated with
a freshly prepared sample of the triflate of (S)-1,2-isopropylidene
glycerol33 (528 mg, 2.0 mmol) at room temperature. After 5 min
an orange precipitate formed, which was collected, washed with
methanol and dried to yield 31 as a yellow solid (390 mg, 90%);
mp 124 ꢁC; Rf (cyclohexane/ethyl acetate 5:1) 0.32; dH (400 MHz,
CDCl3) 4.26 (2H, quin, J 6.0 Hz, 2ꢂ 40-H), 4.11 (2H, dd, J 6.2, 8.4 Hz,
2ꢂ 50-Ha), 3.74 (2H, dd, J 5.4, 8.4 Hz, 2ꢂ 50-Hb), 3.09 (2H, dd, J 5.8,
13.4 Hz, 2ꢂ 40-CHaeS), 2.92 (2H, dd, J 6.6, 13.4 Hz, 2ꢂ 40-CHbeS),
1.40 (6H, s, 2ꢂ eCH3), 1.32 (6H, s, 2ꢂ eCH3); dC (100 MHz, CDCl3)
210.0 (2-C), 136.1 (4-,5-C), 110.1 (2ꢂ 20-C), 74.5 (2ꢂ 40-C), 68.4 (2ꢂ
A mixture of oxo compound 27 (1.70 g, 4.44 mmol), thione 29
(3.00 g, 13.4 mmol) and freshly distilled trimethyl phosphite
(70 ml) was heated to 70 ꢁC for 30 h. The reaction mixture was
cooled to room temperature then filtered and washed with chlo-
roform. The solvent and trimethyl phosphite were removed in
vacuo, the residue was subjected to flash chromatography (SiO2,
eluting with cyclohexane/ethyl acetate 4:1) to yield the donor 30 as
an orange oil (1.07 g, 43.1%); Rf (cyclohexane/ethyl acetate 4:1)
0.26; dH (400 MHz, CDCl3) 5.01 (2H, m, 2ꢂ CHOAc), 3.28 (4H, s, 50-
,60-H2), 2.97 (4H, d, J 5.8 Hz, 2ꢂ CH2S), 2.03 (6H, s, 2ꢂ CH3CO), 1.32
(6H, d, J 6.4 Hz, 2ꢂ CH3); dC (100.6 MHz, CDCl3) 170.0 (2ꢂ C]O),
127.8 (4-,5-C), 113.8 (3a0-,7a0-C), 112.3 & 109.7 (2-,20-C), 69.3 (2ꢂ
CHOAc), 40.8 (2ꢂ CH2S), 30.0 (50-,60-C), 21.0 (2ꢂ CH3CO), 18.9 (2ꢂ
CH3); nmax: 2977, 2929,1732,1420,1369,1228,1127,1092,1035, 955,
889, 857, 772, 632, 606, 395; m/z: (EI) 558 [M]þ; found C, 38.72; H,
50-C), 39.6 (2ꢂ 40-CH2eS), 26.9 (2ꢂ eCH3), 25.3 (2ꢂ eCH3); nmax
:
2990, 2876, 1370, 1214, 1051, 1036, 894, 864, 816, 421; m/z: (ESI)
4.06%, C18H22O4S8 requires C, 38.68; H, 3.97%; [
CHCl3).
a
]
D
293 þ29.3 (c 0.74,
449 [MþNa]þ, 413, 301; HRMS (ESI) found: 449.0008,
C15H22O4S5þNa requires 449.0014; [
a]
293 ꢀ41.6 (c 0.24, THF).
D

8746
I. Awheda et al. / Tetrahedron 69 (2013) 8738e8750
4.13. 4,5-Bis(((40R)-20,20-dimethyl-10,30-dioxolan-40-yl)methyl-
thio)-1,3-dithiol-2-one 32
dd, J 5.8, 13.4 Hz, 2ꢂ 40-CHaeS), 2.81 (2H, dd, J 6.6, 13.4 Hz, 2ꢂ 40-
CHbeS), 1.35 (6H, s, 2ꢂ CH3), 1.29 (6H, s, 2ꢂ CH3); dC (100 MHz,
CDCl3) 127.6 (2ꢂ sp2C), 113.8 (2ꢂ sp2-C), 112.2 & 110.1 (2ꢂ sp2-C
(central)), 109.8 ( 2- & 20-C), 74.4 (2ꢂ 40-C), 68.3 (2ꢂ 50-C) 39.3 (2ꢂ
From 31 (0.39 g, 9.1 mmol) using Method A gave 32 (0.35 g, 93%)
as a yellow oil; Rf (cyclohexane/ethyl acetate 5:1) 0.42; dH
(400 MHz, CDCl3) 4.22 (2H, quin, J 6.0 Hz, 2ꢂ 40-H), 4.07 (2H, dd, J
6.2, 8.4 Hz, 2ꢂ 50-Ha), 3.72 (2H, dd, J 5.4, 8.4 Hz, 2ꢂ 50-Hb), 3.02 (2H,
dd, J 5.8, 13.4 Hz, 2ꢂ 40-CHaeS), 2.87 (2H, dd, J 6.6, 13.4 Hz, 2ꢂ 40-
CHbeS), 1.36 (6H, s, 2ꢂ CH3), 1.28 (6H, s, 2ꢂ CH3); dC (100 MHz,
CDCl3) 188.6 (2-C), 127.1 (4-,5-C), 109.8 ( 2ꢂ 20-C), 74.4 (2ꢂ 40-C),
68.3 (2ꢂ 50-C) 39.3 (2ꢂ 40-CH2eS), 26.8 (2ꢂ eCH3), 25.2 (2ꢂ eCH3);
nmax: 2985, 1668, 1370, 1213, 1149, 1057, 884, 755; m/z: (ESI) 428
[MþNH4]þ, 386, 353, 294, 217, 186; HRMS (ESI) found: 428.0686;
40-CH2eS), 30.1 ( (SCH2)2), 26.8 (2ꢂ eCH3), 25.2 ( 2ꢂ eCH3); nmax
:
2982, 2925, 2873, 1369, 1256, 1212, 1149, 1057, 842, 772; m/z: (ESI)
586 [Mþ], 536, 502, 462, 391, 279, 217, 186; HRMS: (ESI) found:
586.9675, C15H26O4S8þH requires 586.9670 found C, 41.03; H,
4.54%, C15H26O4S8 requires C, 40.93; H, 4.46%; N, 3.20%; [
(c 0.25, THF).
a
]
293 þ28.0
D
4.17. Bis((20R)-20,-30-dihydroxypropyl-10-thio)(ethylenedithio)
TTF 18
[C15H22O5S4þNH4] requires 428.0688 [MþNH4]þ; found C, 35.51;
293
H, 3.84%, C14H18O2S8 requires C, 35.42; H, 3.82%; [
0.28, THF).
a]
þ28.5 (c
From 34 (0.14 g, 0.24 mmol) using Method D, afforded the tetrol
18 (114 mg, 95%) as a brown solid; mp 94 ꢁC; dH (400 MHz,
(CD3)2SO) 4.80 (4H, br 4ꢂ eOH), 3.50 (2H, m, 2ꢂ CHeOH), 3.30 (4H,
m, 2ꢂ eCH2OH), 2.91 (2H, dd, J 6.2, 8.4 Hz, 2ꢂ 10-Ha), 2.75 (2H, dd, J
5.4, 8.4 Hz, 2ꢂ 10-Hb), 2.41 (4H, s, (SCH2)2); dC (100 MHz, (CD3)2SO)
127.0 (2ꢂ sp2C), 112.8 (2ꢂ sp2C), 113.2 & 110.1 (2ꢂ sp2-C (central)),
70.5 (2ꢂ eCH(OH)), 64.2 (2ꢂ eCH2OH), 39.7 (2ꢂ eCH2S), 29.5
((SCH2)2); nmax: 3244 br, 2919, 1395, 1290, 1259, 1182, 1109, 1061,
1016, 877, 767; m/z: (ESI) found: 505 [MꢀH], 503, 501, 491, 455,
364; HRMS (ESI) found: 504.8898, [C14H18O4S8eH] requires:
504.8889; found C, 33.16; H, 3.54%, C14H18O4S8 requires C, 33.18; H,
D
4.14. Tetrakis(((40R)-20,20-dimethyl-10,30-dioxolan-40-yl)meth-
ylthio)TTF 33
A suspension of compound 32 (348 mg, 8.5 mmol) in freshly
distilled triethyl phosphite (7 ml) was heated to 90 ꢁC under ni-
trogen for 6 h. The resulting orange precipitate was filtered off,
washed with n-hexane and dried to afford 33. The triethyl phos-
phite was removed from the filtrate by Kugelrohr distillation, and
residue was washed with hexane, filtered and dried to yield further
donor 33, an orange solid, total yield (169 mg, 51%); mp
146e147 ꢁC; Rf (cyclohexane/ethyl acetate 5:1) 0.22; dH (400 MHz,
CDCl3) 4.28 (4 H, quin, J 6.0 Hz, 4ꢂ 40-H), 4.12 (4H, dd, J 6.2, 8.4 Hz,
4ꢂ 50-Ha), 3.77 (4H, dd, J 5.4, 8.4 Hz, 4ꢂ 50-Hb), 3.06 (4H, dd, J 5.8,
13.4 Hz, 4ꢂ 40-CHaeS), 2.87 (4H, dd, J 6.6, 13.4 Hz, 4ꢂ 40-CHbeS),
1.41 (12H, s, 4ꢂ CH3), 1.32 (12H, s, 4ꢂ CH3); dC (100 MHz, CDCl3)
127.7 (4ꢂ sp2-C), 110.2 (2ꢂ sp2-C), 109.9 (4ꢂ 20-C), 74.8 (4ꢂ 40-C),
68.5 (4ꢂ 50-C) 39.1 (4ꢂ 40-CH2eS), 26.9 (4ꢂ eCH3), 25.4 (4ꢂ eCH3);
nmax: 2985, 2938, 2883, 1369, 1224, 1202, 1150, 1052, 1020, 864, 841,
820, 770, 511, 408 cmꢀ1; m/z: (ESI) 806 [MþNH4]þ, 613, 437, 351,
312, 219, 197; HRMS: (ESI) found: 806.1142, [C30H44O8S8þNH4]
requires: 806.1140; found C, 45.77; H, 5.53%, C30H44O8S8 requires C,
3.58%; [
a
]
293 ꢀ390 (c 0.40, MeOH).
D
4.18. vic-Bis(((4R)-2,2-dimethyl-1,3-dioxolan-4-yl)methyl-
thio)-vic-bis((20R)-20-acetoxypropylthio)TTF 35
From oxo compound 32 (1.10 g, 3.0 mmol) and R,R-26 (1.28 g,
3.0 mmol) and triethyl phosphite (10 ml) following Method C, but
filtering off donor 33 at the end of the reaction, to yield the donor
35 as a brown oil (686 mg, 30%); Rf (cyclohexane/ethyl acetate 3:1)
0.44; dH (400 MHz, CDCl3): 4.97 (2H, m, 2ꢂ 20-H), 4.23 (2H, quin, J
6.0 Hz, 2ꢂ 4-H), 4.10 (2H, dd, J 6.2, 8.4 Hz, 2ꢂ 5-Ha), 3.72 (2H, dd, J
5.4, 8.4 Hz, 2ꢂ 5-Hb), 3.15 (2H, dd, J 5.8, 13.4 Hz, 2ꢂ 4-CHaeS), 2.93
(4H, d, J 5.8 Hz, 2ꢂ 10-H2), 2.80 (2H, dd, J 6.6, 13.4 Hz, 2ꢂ 4-CHbeS),
1.98 (6H, s, 2ꢂ CH3CO), 1.35 (6H, s, 2ꢂ 2-CH3), 1.29 (6H, s, 2ꢂ 2-
CH3), 1.28 (6H, d, J 6.4 Hz, 2ꢂ 30-CH3); dC (100 MHz, CDCl3) 170.0
(2ꢂ C]O), 127.9 (2ꢂ sp2-C), 127.6 (2ꢂ sp2-C), 110.9 & 110.5 (2ꢂ
sp2-C(central)), 109.8 (2ꢂ 2-C), 74.4 (2ꢂ 4-C), 69.3 (2ꢂ20C), 68.3
(2ꢂ 5-C), 40.9 (2ꢂ 10-C), 38.9 (2ꢂ 4-CH2eS), 26.8 (2ꢂ 2-CH3), 25.4
(2ꢂ 2-CH3) 21.0 (2ꢂ CH3CO), 19.0 (2ꢂ 30-CH3); nmax: 3324, 2927,
2850, 1737, 1625, 1517, 1370, 1310, 1229, 1088, 1055, 892, 642, 393;
45.66; H, 5.62%; [
a]
293 þ77.5 (c 0.40, THF).
D
4.15. Tetrakis((20R)-20-,30-dihydroxypropyl-10-thio)TTF 17,
(Method D)
An aqueous solution of HCl (0.5 M, 7 ml) was added to a solution
of tetra-ketal 33 (158 mg, 0.2 mmol) in methanol (10 ml) and tet-
rahydrofuran (3 ml), which was stirred under nitrogen for 12 h.
Evaporation and drying in vacuo at room temperature afforded the
octol 17 (122 mg, 97%) as a brown solid; mp 164e166 ꢁC; dH
(400 MHz, (CD3)2SO) 4.30 (8H, br, 8ꢂ OH), 3.56 (4H, m, 4ꢂ 20-H),
3.45 (8H, m, 4ꢂ 30-H2), 2.93 (4H, m, 4ꢂ 10-Ha), 2.79 (4H, m, 4ꢂ 10-
Hb); dC (100 MHz, (CD3)2SO) 126.9 (4-,40-,5-,50-C), 109.4 (2-,20-C),
70.5 (4ꢂ eCH(OH)), 64.2 (4ꢂ eCH2OH), 39.7 (4ꢂ eCH2S); nmax 3243
br, 2916, 1395, 1229, 1063, 1018, 878, 770 cmꢀ1; m/z: (ESI) 627
[MꢀH]; HRMS (ESI) found: 626.9467, [C18H28O8S8eH] requires
626.9468; found C, 34.30; H, 4.38%, C18H28O8S8 requires C, 34.37; H,
HRMS (ESI) found: 778.0827, [C28H40O8S8þNH4]þ requires:
293
778.0827; [
a
]
þ11.6 (c 0.345, THF).
D
4.19. vic-Bis(((4R)-2,2-dimethyl-1,3-dioxolan-4-yl)methyl-
thio)-vic-bis((20R)-20-hydroxypropylthio)-TTF 36
An aqueous solution (2.5 ml) of potassium carbonate (142 mg,
1.0 mmol) was added to a solution of 35 (100 mg, 0.13 mmol) in
methanol (10 ml) and tetrahydrofuran (1.5 ml), which was stirred
under nitrogen for 12 h. The solvents were evaporated under vac-
uum, and the orange solid collected, washed with water and dried
to yield the chiral diol 29 as a light orange powder (84 mg, 95%);
mp 92e93 ꢁC; Rf (cyclohexane/ethyl acetate 1:1) 0.47; dH (400 MHz,
CD3OD): 4.26 (2H, m, 2ꢂ 4-H), 4.14 (2H, t, J 6.6 Hz, 2ꢂ 5-Ha), 3.88
(2H, m, 2ꢂ 20-Hb), 3.76 (2H, t, J 6.6 Hz, 2ꢂ 5-Hb), 3.07 (2H, dd, J 5.8,
13.4 Hz) and 2.95 (6H, m, 4ꢂ eCH2S), 1.39 (6H, s, 2ꢂ 2-CH3), 1.31
(6H, s, 2ꢂ 2-CH3), 1.25 (6H, d, J 6.4 Hz, 2ꢂ CHCH3); dC (100 MHz,
CD3OD): 129.3 (4ꢂ sp2-C), 110.9 (2ꢂ sp2-C(central)), 109.8 (2ꢂ 2-C),
76.4 (2ꢂ 4-C), 69.5 (2ꢂ 20-C), 67.8 (2ꢂ 5-C), 45.3 (2ꢂ 10-C), 40.1 (2ꢂ
4.49%; [
a
]
293 ꢀ116.6 (c 0.24, THF).
D
4.16. Bis(((40R)-20,20-dimethyl-10,30-dioxan-40-yl)methyl-
thio)(ethylenedithio)TTF 34
Reaction of 29 (0.35 g, 0.85 mmol) and 32 (0.29 g, 1.27 mmol) in
triethyl phosphite (7 ml) at 90 ꢁC using Method B gave the pro-
tected donor 34 (301 mg. 60%) as a red-brown solid; mp 69e71 ꢁC;
Rf (cyclohexane/ethyl acetate 5:1) 0.38; dH (400 MHz, CDCl3) 4.22
(2H, quin, J 6.0 Hz, 2ꢂ 40-H), 4.07 (2H, dd, J 6.2, 8.4 Hz, 2ꢂ 50-Ha),
3.72 (2H, dd, J 5.4, 8.4 Hz, 2ꢂ 50-Hb), 3.20 (4H, s, (SCH2)2), 2.99 (2H,
4-CH2eS), 27.2 (2ꢂ 2-CH3), 25.7 (2ꢂ 2-CH3), 22.3 (2ꢂ 30-CH3); vmax
:
3355, 2984, 1370, 1243, 1226, 1203, 1053, 864, 770 cmꢀ1; found

I. Awheda et al. / Tetrahedron 69 (2013) 8738e8750
8747
293
42.49; H, 5.36%, C24H36O6S8 requires C, 42.57; H, 5.36%; [
a
]
293 þ266
3.12%, C48H54O2N2S4Si requires C, 65.86; H, 6.22; N, 3.20%; [
a
]
D
D
(c 0.015, methanol).
þ5.0 (c 0.2, CHCl3).
4.23. S,S-Bis(N-(100-hydroxyprop-200-yl)pyrrolo[3,4-d])tetra-
thiafulvalene 20
4.20. vic-Bis((2R)-2,3-dihydroxypropylthio)-vic-bis((20R)-20-
hydroxypropylthio)-TTF 19
A mixture of the bis-protected donor 40 (0.85 g, 1.0 mmol) and
tetrabutylammonium fluoride solution (1.0 M in THF, 5.0 ml,
5.0 mmol) in THF (60 ml) was stirred at room temperature for 6 h.
After adding water (5 ml), the solvent was removed. The residue
was washed with ether and then purified by flash chromatography
(SiO2, eluting with ethyl acetate/methanol 9:1) to yield a yellow
solid (283 mg). The solid was stirred with DCM (20 ml) overnight to
give the chiral diol 20 as a yellow solid (193 mg, 49.9%); mp
176e178 ꢁC (dec); Rf (ethyl acetate/methanol 9:1) 0.15; dH
(400 MHz, CDCl3) 6.54 (4H, s, 4-,40-,6-,60-H), 4.08 (2H, m, 2ꢂ 200-H),
3.67 (4H, m, 2ꢂ 100-H2), 1.53 (2H, br, 2ꢂ OH), 1.41 (6H, d, J 7.0 Hz, 2ꢂ
CH3); dC (100.6 MHz, CDCl3) 120.4 (2-,20-C), 119.3 (3a-,3a0-,6a-,6a0-
C), 110.6 (4-,40-,6-,60-C), 67.4 (2ꢂ 100-C), 58.4 (2ꢂ 200-C), 17.4 (2ꢂ 300-
C); nmax: 3385, 1489, 1366, 1301, 1135, 1125, 1114, 1059, 1025, 992,
Donor 36 (100 mg, 0.14 mmol) was hydrolysed following
Method D to yield the chiral hexol 19 (85 mg, 96%) as a deep orange
solid, mp 125e126 ꢁC; Rf (ethyl acetate/methanol 9:1) 0.28; dH
(CD3OD): 3.87 (2H, m, 2ꢂ 2-H), 3.73 (2H, m, 2ꢂ 20-H), 3.59 (4H, m,
2ꢂ 3-H2), 3.02 (2H, m) and 2.90 (6H, m) (2ꢂ 1-H2, 2ꢂ 10-H2), 1.26
(6H, d, J 6.3 Hz, 2ꢂ eCH3); dC (CD3OD) 129.5 (2ꢂ sp2-C), 129.4 (2ꢂ
sp2-C), 110.3 & 109.7 (2ꢂ sp2-C (central)), 72.3 (2ꢂ 2-C), 67.8 (2ꢂ 20-
C), 65.8 (2ꢂ 3-C), 44.3 (2ꢂ 10-C), 40.1 (2ꢂ 1-C), 22.3 (2ꢂ 30-C); vmax
:
3293, 2966, 2918, 1395, 1372, 1066, 1033, 885, 771; found C, 36.13;
293
H, 4.68%, C18H28O6S8 requires C, 36.22; H, 4.73%; [
0.20, THF).
a]
ꢀ40.1 (c
D
4.21. S-5-(10-tert-Butyldiphenylsilyloxyprop-20-yl)-1,3-
dithiolo[4,5-c]pyrrolo-2-thione 39
974, 757, 606; m/z: (EI) 398 [M]þ; found C, 48.29; H, 4.44; N, 6.95%,
293
C16H18N2O2S4 requires C, 48.21; H, 4.55; N, 7.03%; [
a
]
þ27.6 (c
D
A mixture of (2S)-1-(tert-butyldiphenylsilyloxy)propyl-2-amine
3729 (3.51 g, 11.2 mmol), bis(dibromomethyl)-1,3-dithiol-2-
thione28 (3.50 g, 10.9 mmol), sodium carbonate (3.50 g,
33.0 mmol) and tetrabutylammonium iodide (1.00 g, 2.7 mmol) in
THF (120 ml) was refluxed under nitrogen overnight. After removal
of solvent, the residue containing thione 38 was redissolved in
chloroform (200 ml). After cooling to ꢀ15 ꢁC, a solution of DDQ
(3.20 g, 14.1 mmol) in benzene (80 ml) was added dropwise and
resulted in the formation of a dark suspension. The mixture was
stirred for another 2 h and then neutralised with 1 M sodium car-
bonate solution. The mixture was extracted with DCM, and the
combined organic solution was washed with 1 M sodium carbonate
solution and water before drying over magnesium sulfate. The fil-
trate was evaporated at 30 ꢁC in vacuo, and the residue was purified
by flash chromatography (SiO2, eluting with cyclohexane/ethyl
acetate 10:1) to yield the thione 39 as a yellow solid (2.86 g, 52.6%);
mp 114e116 ꢁC (dec); Rf (cyclohexane/ethyl acetate 10:1) 0.28; dH
(400 MHz, CDCl3) 7.58 (2H, m, AreH2), 7.52 (2H, m, AreH2), 7.40
(6H, m, AreH6), 6.77 (2H, s, 4-,6-H), 4.29 (1H, m, 20-H), 3.87 (1H, dd,
J 10.8, 4.1 Hz, 10-Ha), 3.74 (1H, dd, J 10.8, 6.7 Hz, 10-Hb), 1.52 (3H, d, J
6.9 Hz, CH3), 1.08 (9H, s, C(CH3)3); dC (100.6 MHz, CDCl3) 219.0 (2-C),
135.5, 135.4, 133.5, 129.6, 127.6 (AreC12), 122.0 (3a-,6a-C), 110.5 (4-
,6-C), 67.8 (CH2OSi), 58.3 (CHN), 26.4 (C(CH3)3), 18.8 (C(CH3)3), 16.9
(CH3); nmax: 2930, 2855, 1485, 1471, 1427, 1389, 1302, 1138, 1102,
1074, 1051, 1019, 985, 872, 813, 760, 743, 701, 614, 600, 492; m/z:
(EI) 469 [M]þ; found C, 61.42; H, 5.81; N, 2.89%, C24H27NS3Si re-
0.2, THF).
4.24. Diastereoisomers of N-(10-phenyl-ethyl)-2-thioxo-5,6-
dihydro-[1,3]dithiolo[4,5-b][1,4]dithiin-5-yl-acetamide, 43
and 44
A stirred solution of the acid 4130 (2.90 g, 10.3 mmol) and trie-
thylamine (1.70 ml, 12.2 mmol) in dry THF (100 ml) under a nitro-
gen atmosphere was cooled to 0 ꢁC and ethyl chloroformate (1.34 g,
12.3 mmol) was added. After stirring for 10 min a solution of (R)-
(þ)-
a-methylbenzylamine (2.50 g, 20.6 mmol) in THF (10 ml) was
added. The solution was allowed to warm to room temperature and
then stirred overnight. Removal of the solvent and column chro-
matography (cyclohexane/ethyl acetate 3:1) gave, after elution of
unreacted chiral amine, two yellow fractions:
(5R,10R) isomer 43 (1.12 g, 28.3%), yellow feathery needles, mp
135e137 ꢁC, Rf (cyclohexane/ethyl acetate 3:1) 0.26; dH (400 MHz,
CDCl3) 7.26 (5H, m, AreH5), 5.94 (1H, d, J 7.7 Hz, NeH), 5.04 (1H,
quin, J 7.1 Hz, NeCH), 4.11 (1H, m, 5-H), 3.34 (1H, dd, J 2.8, 13.5 Hz,
6-Ha), 3.06 (1H, dd, J 5.3, 13.5 Hz, 6-Hb), 2.67 (2H, d, J 7.1 Hz, (O]C)
CH2),1.43 (3H, d, J 6.8 Hz, CH3); dC (100.6 MHz, CDCl3) 207.65 (C]S),
167.67 (C]O), 142.47, 128.76, 127.63 & 126.09 (AreC6), 122.55 &
120.85 (3a-,7a-C), 49.21 (NeCH), 41.39 (O]CeCH2), 38.24 (5-C),
34.07 (6-C), 21.66 (CH3); nmax: 3144, 3072, 2960, 2888, 1648, 1552,
1500, 1456, 1420, 1372, 1240, 1060; m/z: (CI): 403 ([MþNH4]þ), 388,
387, 386 ([MþH]þ), 385, 356, 312, 280; HRMS (CI): found 384.9750,
quires C, 61.36; H, 5.79; N, 2.98%; [
a]
293 ꢀ11.7 (c 0.06, THF).
297
D
C15H15NOS5 requires: 384.9752; [
a
]
þ122 (c 0.46, DCM).
D
(5S,10R) isomer 44 (1.10 g, 27.8%), yellow plates, mp 161e163 ꢁC, Rf
(cyclohexane/ethyl acetate 3:1) 0.14; dH (400 MHz, CDCl3) 7.26 (5H,
m, AreH5), 5.84 (1H, d, J 7.4 Hz, NH), 5.05 (1H, quin, J 7.1 Hz, NeCH),
4.11 (1H, m, 5-H), 3.41 (1H, dd, J 2.7,13.5 Hz, 6-Ha), 3.20 (1H, dd, J 5.3,
13.5 Hz, 6-Hb), 2.71 (1H, dd, J 7.1, 15.4 Hz, (O]C)CHa), 2.63 (1H, dd, J
7.1, 15.4 Hz, (O]C)CHb), 1.44 (3H, d, J 7.1 Hz, CH3); dC: 207.63 (C]S),
167.63 (C]O), 142.71, 128.74, 127.56 & 126.01 (AreC6), 122.62 &
121.00 (3a-,7a-C), 49.28 (NeCH), 41.42 (O]CeCH2), 38.32 (5-C),
33.92 (6-C), 21.77 (CH3); nmax: 3108, 2936, 2864, 1636, 1552, 1504,
1456, 1348, 1318, 1300, 1264, 1060; m/z: (CI): 403([MþNH4]þ), 386
([MþH]þ), 385, 387, 312, 280; HRMS (CI) found: 384.9756,
4.22. S,S-Bis(N-100-tert-butyldiphenylsilyloxyprop-200-yl)pyr-
rolo[3,4-d]tetrathiafulvalene 40
Reaction of 39 (2.84 g, 6.05 mmol) in trimethyl phosphite
(70 ml) using Method B and refluxing for 51 h gave the donor 40 as
a yellow solid (0.85 mg, 32.1%); mp 86e88 ꢁC (dec); Rf (cyclohex-
ane/ethyl acetate 10:1) 0.39; dH (400 MHz, CDCl3) 7.45 (4H, m,
AreH4), 7.39 (4H, m, AreH4), 7.30 (12H, m, AreH12), 6.40 (4H, s, 4-
,6-,40-,60-H), 3.99 (2H, m, 2ꢂ 200-H), 3.63 (2H, dd, J 10.2, 4.5 Hz, 2ꢂ
100-Ha), 3.55 (2H, dd, J 10.2, 6.4 Hz, 2ꢂ 100-Hb), 1.35 (6H, d, J 6.8 Hz,
2ꢂ CH3), 0.94 (18H, s, 2ꢂ C(CH3)3); dC (100.6 MHz, CDCl3) 135.6,
135.5, 133.0, 132.7, 129.9, 129.7, 127.8 (AreC20), 120.0 (2-,20-C), 118.6
(3a-,3a0-,6a-,6a0-C), 110.9 (4-,40-,6-,60-C), 68.3 (2ꢂ 100-C), 57.9 (2ꢂ200-
C), 26.7 (2ꢂ C(CH3)3), 19.1 (2ꢂ C(CH3)3), 17.2 (2ꢂ 300-C); nmax: 2930,
2856, 1488, 1471, 1427, 1368, 1301, 1104, 1071, 1021, 824, 759, 740,
699, 609, 501, 485; m/z: (EI) 874 [M]þ; found C, 65.75; H, 6.18; N,
C15H15NOS5 requires: 384.9752; [
a]
297 ꢀ176 (c 0.39, DCM).
D
4.25. (10R,5R)-N-(10-Phenyl-ethyl)-(BEDT-TTF)-acetamide 21
A solution of thione 43 (573 mg, 1.923 mmol) and the unsub-
stituted oxo compound 45 (620 mg, 3.846 mmol) in triethyl

8748
I. Awheda et al. / Tetrahedron 69 (2013) 8738e8750
phosphite (10 ml) was stirred overnight at 90 ꢁC. After cooling, the
volatiles were removed under vacuum and the crude material pu-
rified by column chromatography (eluting with cyclohexane/ethyl
acetate 3:1) to afford the donor 21 (253 mg, 31%) as an orange-red
glassy solid, mp 125e127 ꢁC dec; Rf (cyclohexane/ethyl acetate 3:1)
0.24; dH (400 MHz, CDCl3): 7.22 (5H, m, AreH5), 5.93 (1H, d, J 7.8 Hz,
NeH), 5.03 (1H, quin, J 7.4 Hz, NeCH), 4.02 (1H, m, 5-H), 3.24 (1H,
dd, J 3.1, 13.4 Hz, 6-Ha), 3.21 (4H, s, 50-,60-H2), 2.94 (1H, dd, J 4.8,
13.3 Hz, 6-Hb), 2.57 (2H, d, J 7.2 Hz, (O]C)CH2), 1.42 (3H, d, J 6.9 Hz,
CH3); dC (100.6 MHz, CDCl3): 168.1 (C]O), 142.9, 128.7, 127.4 &126.0
(AreC6), 113.8, 113.7, 112.7, 112.1, 112.0 & 111.2 (6ꢂ sp2-C), 49.2
(NeCH), 41.6 (O]CeCH2), 38.5 (5-C), 34.6 (6-C), 30.1 (50-,60-C), 21.8
(CH3); nmax: 3300, 2970, 2924, 1713, 1650, 1543, 1449, 1366, 1263;
m/z (CI): 563 ([MþNH4]þ), 546 ([MþH]þ), 462, 391, 279, 217; HRMS
(CI): found 545.9298, (C20H19NOS8þH) requires 545.9305; found C,
43.85; H, 3.38; N, 2.64%, C20H19NOS8 requires C, 43.87; H, 3.40; N,
(2ꢂ 5-,6-CH2); nmax: 3001, 2944, 1733, 1716, 1684, 1647, 1626, 1505,
1435, 1398, 1363, 1258, 1204, 1170, 1150, 1055, 978, 927, 778, 554;
found C, 37.38; H, 3.34%, C11H12O5S4 requires C, 37.49; H, 3.42%.
4.29. Dimethyl vic-trans-BEDT-TTF-diacetate 48
From 47 (1.97 g, 5.61 mmol) and 29 (3.14 g, 14.0 mmol) and
trimethyl phosphite (60 ml) using Method C gave the trans diester
48, as an orange solid (1.64 g, 55.3%); mp 136e138 ꢁC; Rf (cyclo-
hexane/ethyl acetate 2:1) 0.62; dH (400 MHz, CDCl3): 3.73 (2H, m, 5-
,6-H), 3.69 (6H, s, 2ꢂ OCH3), 3.25 (4H, s, 50-,60-H2), 2.77 (4H, m, 2ꢂ
5-,6-CH2); dC (100.6 MHz, CDCl3): 170.6 (2ꢂ C]O), 113.8, 112.0,
110.3, 110.0 (2-,20-,3a-,3a0-,7a-,7a0-C), 52.1 (2ꢂ OCH3), 41.0 (2ꢂ 5-,6-
CH2), 40.7 (5,6-C), 30.1 (50-,60-C); nmax: 2956, 2918, 1732, 1436, 1414,
1367, 1338,1308,1288,1258,1239,1214,1191, 1138, 1152,1093,1031,
1011, 988, 912, 873, 848, 772; found C, 36.41; H, 2.95%, C16H16O4S8
requires C, 36.34; H, 3.05%.
2.64%; [
a
]
293 þ2.1 (c 0.147, DCM).
D
4.26. (10R,5S)-N-(10-Phenyl-ethyl)-(BEDT-TTF)-acetamide 22
4.30. vic-trans-BEDT-TTF-di(acetic acid) 23
Following the procedure for 21, thione 44 (600 mg, 1.56 mmol)
and oxo compound 45 (810 mg, 3.89 mmol) in triethyl phosphite
(14 ml) afforded the donor 22 (185 mg, 46%) as a pink solid, mp
148e158 ꢁC dec Rf (cyclohexane/ethyl acetate 3:1) 0.22; dH
(400 MHz, CDCl3) 7.29 (5H, m, Ar-H5), 6.09 (1H, d, J 7.8 Hz, NeH),
5.07 (1H, quin, J 7.3 Hz, NeCH), 4.03 (1H, m, 5-H), 3.33 (1H, dd, J 3.0,
13.3 Hz, 6-Ha), 3.26 (4H, s, 50-,60-H2), 3.11 (1H, dd, J 4.9, 13.3 Hz, 6-
Hb), 2.66 (1H, dd, J 6.8, 15.1 Hz, (O]C)CHa), 2.59 (1H, dd, J 7.2,
15.1 Hz, (O]C)CHb), 1.45 (3H, d, J 6.8 Hz, CH3); dC (100.6 MHz,
CDCl3) 168.2 (C]O), 142.6, 128.7, 127.5 & 126.1 (AreC6), 113.8, 112.6,
112.2, 111.7 & 111.3 (6ꢂ sp2-C), 49.1 (NeCH), 41.6 (O]CeCH2), 38.4
(5-C), 34.7 (6-C), 30.1 (50-,60-C), 21.7 (CH3); nmax: 3297, 3050, 2976,
2925, 1642, 1542, 1448, 1410, 1373, 1263, 1159, 1127, 1018; m/z:
568([MþNH4]þ), 546([MþH]þ), 443, 357, 217; HRMS (CI) found:
545.9299, (C20H19NOS8þH) requires: 545.9305; found C, 43.83; H,
Diester 48 (200 mg, 0.38 mmol) and potassium hydrogen car-
bonate (300 mg, 3.00 mmol) were dissolved in a mixture of
methanol (9 ml), THF (10 ml) and water (5 ml) and refluxed to-
gether for 2 h. The filtered mixture was evaporated and extracted
between water and dichloromethane. The aqueous layer was
carefully acidified with 1 M hydrochloric acid and the suspension
produced stirred in an ice bath for 1 h and filtered to give a product
with a 1:1 composition of 23 and its monopotassium salt, as a yel-
low-brown powder (80 mg, 41%), which was insoluble in organic
solvents; mp 170e173 ꢁC (dec); nmax: 2916 br, 1702, 1437, 1404,
1288, 1248, 1222, 1163, 1001, 884. Found C: 32.7; H: 2.1%
C14H12O4S8. C14H11O4S8K requires C: 32.3; H: 2.2%.
4.31. exo-5,8-Methano-4a,5,6,7,8,8a-hexahydro-1,3-dithiolo
[4,5-b]benzo-1,4-dithiin-2-thione 49
3.40; N, 2.70%, C20H19NOS8 requires C, 43.92; H, 3.40; N, 2.64%;
297
[
a]
ꢀ68 (c 0.17, CH2Cl2).
Norbornene (4.00 g, 42.4 mmol) and trithione 41 (8.30 g,
42.4 mmol) were refluxed together in toluene (500 ml) for 27 h and
filtered. The filtrate was evaporated to dryness and the residue
refluxed in methanol (50 ml) for 30 min. After cooling to room
temperature, filtration gave thione 49 (11.69 g, 95%) as thin yellow
plates, mp 172e174 ꢁC; Rf (cyclohexane/ethyl acetate 4:1) 0.78; dH
(400 MHz, CDCl3): 3.39 (2H, s, 4a-,8a-H), 2.37 (3H, br, 5-,8-,10a-H),
1.66 (2H, d*, J 8.8 Hz, 6a-,7a-H), 1.33 (1H, d, J 10.8 Hz, 10b-H), 1.27
(2H, d*, J 8.8 Hz, 6b-,7b-H) *some further coupling; dC (100.6 MHz,
CDCl3): 209.9 (C]S), 136.5 (3a-,9a-C), 60.3 (4a-,8a-C), 44.3 (5-,8-C),
35.3 (10-C), 29.1 (6-,7-C); nmax: 2951, 2870, 1466, 1449, 1300, 1180,
1145, 1057, 1005, 928, 887, 783, 510, 492, 465, 448; found: C, 41.29;
H, 3.43%, C10H10S5 requires: C, 41.35; H, 3.47%.
D
4.27. Dimethyl trans-5,6-dihydro-2-thioxo-1,3-dithiolo[4,5-b]
dithiin-5,6-diacetate 46
A suspension of trithione 41 (3.10 g, 15.8 mmol) and dimethyl E-
hex-3-enedioate (2.75 g,16.0 mmol) in toluene (100 ml) was heated
to reflux for 48 h under nitrogen. After evaporation of toluene, the
residue was dissolved in chloroform, warmed with charcoal for
10 min, filtered and evaporated. The residue was purified by flash
chromatography (SiO2, eluting with cyclohexane/ethyl acetate 2:1),
and the main fraction evaporated and stirred with hexane for 2
days to remove alkene starting material. Filtration and evaporation
solution afforded thione 46 (4.41 g, 75.8%) as a yellow powder; mp
90e92 ꢁC; Rf (cyclohexane/ethyl acetate 3:1) 0.36; dH (400 MHz,
CDCl3): 3.83 (2H, m, 5-,6-H), 3.73 (6H, s, 2ꢂ OCH3), 2.86 (4H, m, 5-
,6-CH2); dC (100.6 MHz, CDCl3): 206.9 (C]S), 170.3 (2ꢂ C]O), 118.8
4.32. Dimethyl trans-exo-cyclopentan-100,300-BEDT-TTF-
5,6-diacetate diastereomers 50, 51
(3a-,7a-C), 52.3 (2ꢂ OCH3), 40.9 (2ꢂ 5-,6-CH2), 40.7 (5-,6-C); nmax
:
Oxo compound 47 (1.50 g, 4.26 mmol) and thione 49 (3.14 g,
10.81 mmol) in trimethyl phosphite following Method C gave, after
chromatography, a 1:1 mixture of 50 and 51 (0.90 g, 35.7%) as an
orange solid, mp 164e168 ꢁC; Rf (cyclohexane/ethyl acetate 4:1)
0.34; two diastereomers showing very similar 1H & 13C NMR sig-
nals: dH (400 MHz, CDCl3) 3.73 (2H, m, 5-,6-H), 3.66 and 3.56 (6H, s,
2ꢂ OCH3, two isomers), 3.32 (2H, s, 50-,60-H), 2.75 (4H, m, 5,6-
CH2CO), 2.32 (2H, s, 100-,300-H), 2.30 (1H, d, J 11 Hz, 200a-H), 1.61 (2H,
d, J 8 Hz, 400a-,500a-H), 1.24 (1H, d, J 11 Hz, 200b-H), 1.23 (2H, d, J 8 Hz,
400b-,500b-H); dC (CDCl3): 170.7 (2ꢂ C]O), 126.9 (3a0-,7a0-C), 112.7,
110.7, 110.4, 108.5 (2-,20-,3a-,7a-C), 59.7 (50-,60-C), 52.2 & 52.1 (2ꢂ
OCH3), 44.3, 41.5, 40.8, 40.2 (5-,6-C, 5,6-CH2CO, 100-300-C, two iso-
mers), 35.1 (200-C), 29.1 (400-,500-C); nmax: 2947, 2869, 1729, 1435,
2949, 1719, 1486, 1437, 1369, 1249, 1206, 1158, 1062, 1031, 1016, 973,
921, 886, 810, 574, 516; found C, 35.91; H, 3.23%, C11H12O4S5 re-
quires C, 35.85; H, 3.28%.
4.28. Dimethyl trans-5,6-dihydro-2-oxo-1,3-dithiolo[4,5-b]di-
thiin-5,6-diacetate 47
From 46 (1.84 g, 5.03 mmol) using Method A afforded 47 (1.67 g,
94.3%) as a pale orange solid; mp 79e81 ꢁC; Rf (cyclohexane/ethyl
acetate 3:1) 0.40; dH (400 MHz, CDCl3): 3.75 (2H, m, 5-,6-H), 3.67
(6H, s, 2ꢂ OCH3), 2.87 (4H, m, 5-,6-CH2); dC (100.6 MHz, CDCl3):
170.5 (C]O), 109.5 (3a-,7a-C), 52.2 (2ꢂ OCH3), 42.0 (5-,6-C), 40.9

I. Awheda et al. / Tetrahedron 69 (2013) 8738e8750
8749
1396, 1357, 1300, 1215, 1197, 1165, 1143, 1003, 971, 920, 893, 877,
Supplementary data
771, 651, 603, 493; m/z: (EI) 528 [M]þ; HRMS (ES, with ammonium
acetate) found: 594.9351, [MþH]þ, C21H22O4S8þH requires:
594.9357; found C, 42.50; H, 3.56%, C21H22O4S8 requires C, 42.40; H,
3.73%.
Supplementary data related to this article can be found at http://
dx.doi.org/10.1016/j.tet.2013.07.089.
References and notes
4.33. X-ray crystallography
1. (a) Ferraris, J.; Cowan, D. O.; Walatka, V. V., Jr.; Perlstein, J. H. J. Am. Chem. Soc.
1973, 95, 948e949; (b) Coleman, L. B.; Cohen, M. J.; Sandman, D. J.; Yamagishi,
F. G.; Garito, A. F.; Heeger, A. Solid State Commun. 1973, 12, 1125e1132; (c) Wudl,
F. Acc. Chem. Res. 1984, 17, 227e232.
2. (a) Day, P. C. R. Chim. 2003, 6, 301e308; (b) Mori, H. Opt. Sci. Eng. 2008, 133,
263e285; (c) Singleton, J. J. Solid State Chem. 2002, 168, 675e689.
3. (a) Herranz, M.; Sanchez, L.; Martin, N. Phosphorous, Sulfur Silicon Relat. Elem.
2005, 180, 1133e1148; (b) Bendikov, M.; Wudl, F.; Perepichka, D. F. Chem. Rev.
2004, 104, 4891e4946; (c) Bryce, M. R.; Davenport, W.; Goldenberg, L. M.;
Wang, C. Chem. Commun. 1998, 945e952.
Crystal structures were measured using Mo K
a radiation at
120 K, solved with SHELXS-97 and refined with SHELXL-9734 using
the X-SEED interface.35 Molecular illustrations are made with
ORTEP-336 and Mercury37 using POVRAY.38 Data is deposited at the
Cambridge Crystallographic Data Centre, 12 Union Road, Cam-
bridge, CB2 1EZ with reference numbers CCDC 924767e924772.
Crystal data for 15: C18H28O4S8, Mr¼564.88, orthorhombic,
3
ꢁ
ꢁ
a¼9.7257(3), b¼9.8612(4), c¼26.3649(11) A, V¼2528.58(17) A ,
4. (a) Wallis, J. D.; Griffiths, J.-P. J. Mater. Chem. 2005, 15, 347e365; (b) Brown, R. J.;
Brooks, A. C.; Griffiths, J.-P.; Vital, B.; Day, P.; Wallis, J. D. Org. Biomol. Chem.
2007, 5, 3172e3182.
Z¼4, P212121, Dc¼1.48 g cmꢀ3
,
m
(Mo K
a
)¼0.073 mmꢀ1, T¼120(2) K,
5533 unique reflections, 4269 with F>4
s(F), R¼0.049, wR¼0.090.
ꢀ
5. (a) Canevet, D.; Salle, M.; Zhang, G.; Zhang, D.; Zhu, D. Chem. Commun. 2009,
Crystal data for 44: C15H15NOS5, Mr¼385.58, monoclinic,
2245e2269; (b) Bryce, M. R. J. Mater. Chem. 2000, 10, 589e598.
ꢁ
6. 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, 333e337.
a¼5.1301(3), b¼9.2119(5), c¼17.9448(10) A,
a
¼90.0, ¼94.715(5),
b
3
ꢀ3
, m
ꢁ
ꢁ
g
¼90.0 , V¼845.715(5) A , Z¼2, P21, Dc¼1.52 g cm
(Mo K
a
)¼
0.685 mmꢀ1, T¼120(2) K, 3866 unique reflections, 3703 with
ꢀ
7. Lyskawa, J.; Canevet, D.; Allain, M.; Salle, M. Tetrahedron Lett. 2010, 51,
F>4s
(F), R¼0.033, wR¼0.088, Flack parameter: 0.02(8).
5868e5872.
8. Mas-Torrent, M.; Rovira, C. Chem. Rev. 2011, 111, 4833e4856.
9. Nielsen, M. B. Phosphorous, Sulfur Silicon Relat. Elem. 2011, 186, 1055e1073.
10. (a) Danila, I.; Riobe, F.; Piron, F.; Puigmarti-Luis, J.; Wallis, J. D.; Linares, M.;
Agren, H.; Beljonne, D.; Amabilino, D. B.; Avarvari, N. J. Am. Chem. Soc. 2011,
133, 8344e8353; (b) Danila, I.; Riobe, F.; Puigmarti-Luis, J.; Perez del Pino, A.;
Wallis, J. D.; Amabilino, D. B.; Avarvari, N. J. Mater. Chem. 2009, 19,
4495e4504.
11. (a) Krstic, V.; Roth, S.; Burghard, M.; Kern, K.; Rikken, G. L. J. A. J. Chem. Phys.
2002, 117, 11315e11319; (b) Krstic, V.; Rikken, G. L. J. A. Chem. Phys. Lett. 2002,
364, 51e56; (c) Rikken, G. L. J. A.; Folling, J.; Wyder, P. Phys. Rev. Lett. 2001, 87
236602/1e4.
12. (a) Amabilino, D. B.; Veciana, J. Top. Curr. Chem. 2006, 26, 253e302; (b) Per-
ruchas, S.; Boubekeur, K.; Batail, P. Cryst. Growth Des. 2005, 5, 1585e1596; (c)
Giffard, M.; Pilet, G.; Allain, M.; Hudhomme, P.; Mabon, G.; Levillain, E.; Gor-
gues, A.; Riou, A. Chem. Commun. 2001, 2722e2723; (d) Li, H.; Zhang, D.; Zhang,
B.; Yao, Y.; Xu, W.; Zhu, D.; Wang, Z. J. Mater. Chem. 2000, 10, 2063e2067; (e)
Heuze, K.; Fourmigue, M.; Batail, P.; Canadell, E.; Auban-Senzier, P. Chem.dEur.
J. 1999, 5, 2971e2976.
Crystal data for 49: C10H10S5, Mr¼290.48, monoclinic,
a¼6.3435(1), b¼7.3999(2), c¼12.5755(4) A,
b
¼90.915(2)ꢁ,
ꢁ
3
ꢁ
ꢀ3
, m
V¼590.23 A , Z¼2, P21, Dc¼1.634 g cm
(Mo K
a
)¼0.94 cmꢀ1
,
T¼120(2) K, 2488 unique reflections, 2415 with F>4
s
(I), R¼0.042,
wR¼0.108.
Crystal data for (16)4[Fe2(oxalate)5]: 4C14H18O2S8.C10O20
Fe2, Mr¼2450.86, monoclinic, a¼13.8685(4), b¼21.8745(8),
3
ꢁ
c¼15.4879(5) A,
b
¼100.678(2)ꢁ, V¼4617.1(3) A , Z¼2, P21,
ꢁ
Dc¼1.76 g cmꢀ3
,
m(Mo K
a
)¼1.114 mmꢀ1, T¼120(2) K, 19,353 unique
reflections, 14,466 with F>4
s
(F), R¼0.071, wR¼0.136.
Crystal data for 16$TCNQ-F4: C14H18O2S8.C12N4F4, Mr¼750.92,
ꢁ
triclinic,
a¼8.8930(2),
b¼12.4995(2),
c¼13.9897(3)
A,
3
ꢁ
ꢁ
a
¼89.2960(10),
b
¼74.2240(10),
g
¼86.8580(10) , V¼1494.24(5) A ,
Z¼2, P1, Dc¼1.67 g cmꢀ3
,
m
(Mo K
a
)¼0.066 mmꢀ1, T¼120(2) K,
13. Krivickas, S. J.; Ichikawa, A.; Takahashi, K.; Tajima, H.; Wallis, J. D.; Mori, H.
Synth. Met. 2011, 161, 1563e1565.
13,037 unique reflections, 11,743 with F>4
s
(F), R¼0.033, wR¼0.081.
ꢀ
ꢀ
Crystal data for 18$I3: C14H18O4S8.I3, Mr¼887.46, monoclinic,
14. (a) Coronado, E.; Galan-Mascaros, J. R.; Coldea, A. I.; Goddard, P.; Singleton, J.;
a¼19.1095(7), b¼10.1013(3), c¼13.8161(6) A,
b
¼110.103(4)ꢁ,
ꢁ
ꢀ3
Wallis, J. D.; Coles, S. J.; Alberola, A. J. Am. Chem. Soc. 2010, 132, 9271e9273; (b)
ꢀ
Chas, M.; Lemarie, M.; Gulea, M.; Avarvari, N. Chem. Commun. 2008, 220e224;
3
ꢁ
V¼2504.45(16) A , Z¼4, C2, Dc¼2.35 g cm
, m
¼4.43 mmꢀ1
,
,
ꢀ
(c) Chas, M.; Riobe, F.; Sancho, R.; Minguíllon, C.; Avarvari, N. Chirality 2009, 21,
T¼150 K, 3845 unique reflections (Rint¼0.0249), 3282 with F2>2
s
818e825.
R(F, F2>2
s
)¼0.038, Rw(F2, all data)¼0.084.
ꢀ
ꢀ
ꢀ
15. (a) Rethore, C.; Avarvari, N.; Canadell, E.; Auban-Senzier, P.; Fourmigue, M. J. Am.
ꢀ
ꢀ
ꢀ
Chem. Soc. 2005, 127, 5748e5749; (b) Rethore, C.; Madalan, A.; Fourmigue, M.;
Canadell, E.; Lopes, E. B.; Almeida, M.; Clerac, R.; Avarvari, N. New J. Chem. 2007,
31, 1468e1483.
4.34. Conductivity measurements
16. Yang, S.; Brooks, A. C.; Martin, L.; Day, P.; Li, H.; Horton, P.; Male, L.; Wallis, J. D.
CrystEngComm 2009, 11, 993e996.
Two-probe DC transport measurements were made on several
crystals of 16$Fe(III)2(oxalate)5 and 18$I3, respectively, using
a HUSO HECS 994C multi-channel conductometer. Gold wires
17. Yang, S.; Brooks, A. C.; Martin, L.; Day, P.; Pilkington, M.; Clegg, W.; Harrington,
R. W.; Russo, L.; Wallis, J. D. Tetrahedron 2010, 66, 6977e6989.
ꢀ
ꢀ
18. (a) Gomez, R.; Segura, J. L.; Martin, N. Org. Lett. 2000, 2, 1585e1587; (b) Gomez,
R.; Segura, J. L.; Martin, N. J. Org. Chem. 2000, 65, 7566e7574; (c) Saad, A.;
(15 mm diameter) were attached to the crystal, and the attached
ꢀ
Jeannin, O.; Fourmigue, M. New J. Chem. 2011, 35, 1004e1010.
19. Zhou, Y.; Zhang, D.; Zhu, L.; Shuai, Z.; Zhu, D. J. Org. Chem. 2006, 71, 2123e2130.
20. Gomar-Nadal, E.; Rovira, C.; Amabilino, D. B. Tetrahedron 2006, 62, 3370e3379.
21. Kitamura, T.; Nakaso, S.; Mizoshita, N.; Tochigi, Y.; Shimomura, T.; Moriyama,
M.; Ito, K.; Kato, T. J. Am. Chem. Soc. 2005, 127, 14769e14775.
wires were connected to an eight-pin integrated circuit plug with
gold conductive cement.
22. (a) Coronado, E.; Galan-Mascaros, J. R. J. Mater. Chem. 2005, 15, 66e74; (b)
Avarvari, N.; Wallis, J. D. J. Mater. Chem. 2009, 19, 4061e4076.
23. (a) Leurquin, F.; Ozturk, T.; Pilkington, M.; Wallis, J. D. J. Chem. Soc., Perkin Trans.
1 1997, 3173e3178.
24. (a) Booth, S.; Wallace, E. N. K.; Singhal, K.; Bartlett, P. N.; Kilburn, J. D. J. Chem.
Soc., Perkin Trans. 1 1998, 1467e1474; (b) Alea, G. V.; Janairo, G. C.; Kilburn, J. D.
Philipp. J. Sci. 2007, 136, 33e43.
25. (a) Svenstrup, N.; Becher, J. Synthesis 1995, 215e325; (b) Wang, C.; Batsanov, A.
S.; Bryce, M. R.; Howard, J. A. K. Synthesis 1998, 1615e1618.
26. Further details are supplied in Supplementary data.
27. (a) Rashid, S.; Turner, S. S.; Day, P.; Light, M. E.; Hursthouse, M. B.; Guionneau, P.
Synth. Met. 2001, 120, 985e986; (b) Coronado, E.; Galan-Mascaros, J. R.; Gomez-
Garcia, C. J. J. Chem. Soc., Dalton Trans. 2000, 205e210.
28. Jeppesen, J. O.; Becher, J. Eur. J. Org. Chem. 2003, 3245e3266.
29. Jeppesen, J. O.; Takimiya, K.; Jensen, F.; Brimert, T.; Nielsen, K.; Thorup, N.;
Becher, J. J. Org. Chem. 2000, 65, 5794e5805.
Acknowledgements
We thank the EPSRC for grant EP/C510488/1 and for a student-
ship (A.C.B.), the UK Higher Education Innovation Fund for support
(S.J.K.), the Libyan Ministry of Higher Education and Al-Mergheb
University for a Ph.D. scholarship (I.A.), the EPSRC National Crys-
tallography Service for datasets and the EPSRC Mass Spectrometry
Service for measurements. We thank the United Kingdom Chemical
Database Service39 for access to the Cambridge Structural Data-
base.40 The work has benefited from support from ESF COST action
D35. We thank Brian O’Neilland Peter Moore for construction of
constant current sources.

8750
I. Awheda et al. / Tetrahedron 69 (2013) 8738e8750
30. Brickmann, K.; Yuan, Z.-Q.; Sethson, I.; Somfai, P.; Kihlberg, J. Chem.dEur. J.
1999, 5, 2241e2253.
34. Sheldrick, G. M. Acta Crystallogr., Sect. A 2008, 64, 112e122.
35. Barbour, L. J. J. Supramol. Chem. 2001, 1, 189e193.
31. Brown, R. J.; Cameresa, G.; Griffiths, J.-P.; Day, P.; Wallis, J. D. Tetrahedron Lett.
36. Farrugia, L. J. J. Appl. Crystallogr. 1997, 30, 565e566.
2004, 45, 5103e5107.
32. Guionneau, P.; Kepert, C. J.; Bravic, G.; Chasseau, D.; Truter, M. R.; Kurmoo, M.;
Day, P. Synth. Met. 1997, 86, 1973e1974.
33. (a) Aktoudianakis, E.; Celebi, A. A.; Du, Z.; Jabri, S. Y.; Jin, H.; Kim, C. U.; Li, J.;
Metobo, S. E.; Mish, M. R.; Phillips, B. W.; Saugier, J. H.; Yang, Z. -Y.; Zonte, C. S.
PCT Int. Appl., 2010, WO 2010011959 A1 20100128; (b) Cassel, S.; Debaig, C.;
Benvegnu, T.; Chaimbault, P.; Lafosse, M.; Plusquellec, D.; Rollin, P. Eur. J. Org.
Chem. 2001, 875e896.
37. Macrae, C. F.; Edgington, P. R.; McCabe, P.; Pidcock, E.; Shields, G. P.; Taylor, R.;
Towler, M.; van de Streek, J. J. Appl. Crystallogr. 2006, 39, 453e457.
38. Persistence of Vision Pty. Ltd. Persistence of Vision (TM) Raytrace; Persis-
tence of Vision Pty. Ltd.: Williamstown, Victoria, Australia; http://www.
povray.org/.
39. The United Kingdom Chemical Database Service; Fletcher, D. A.; McMeeking, R.
F.; Parkin, D. J. Chem. Inf. Comput. Sci. 1996, 36, 746e749.
40. Allen, F. H. Acta Crystallogr., Sect. B 2002, 58, 380e388.