Vilsmeier-Haack Type Formylation on 6-Aryl-1,4-dithiafulvenes and Syntheses of Novel Extended Tetrathiafulvalene Donors

Article abstract of DOI:10.1055/s-0035-1560400

The Vilsmeier-Haack type formylations on various 6-aryl-1,4-dithiafulvenes were examined. The furyl derivatives on treatment with an excess of POCl₃ in DMF at room temperature mainly afforded dialdehydes substituted at the 6-position and the furan ring, while the thienyl derivatives and the phenyl derivatives mainly gave monoformylated derivatives substituted at the 6-position. The obtained mono- and dialdehydes were converted into monoaryl-substituted 2,2′-ethanediylidene-bis(1,3-dithiole) derivatives and heteroaromatic ring-inserted [3]dendralene derivatives with triple 1,3-dithiol-2-ylidenes and their TTF-fused analogues. Electrochemical properties of the new π-electron donors were also investigated by cyclic voltammetry.

Full text of DOI:10.1055/s-0035-1560400

SYNTHESIS
0
0
3
9
-
7
8
8
1
1
4
3
7
-
2
1
0
X
© Georg Thieme Verlag Stuttgart · New York
2016, 48, A–J
paper
A
A. Fujioka et al.
Paper
Synthesis
Vilsmeier–Haack Type Formylation on 6-Aryl-1,4-dithiafulvenes
and Syntheses of Novel Extended Tetrathiafulvalene Donors
Atsushi Fujiokaa
Takashi Kuboa
Miho Watanabea
Masafumi Uedaa
Hisakazu Miyamotoa,1
Yohji Misaki*a,b
CHO
R1
R1
R1
R1
R1
X
S
S
S
S
X
S
S
X
1) POCl3/DMF
2) NaOH/H2O
+
R1
CHO
10–91%
CHO
X = O, S
R1 = CO2Me, SMe
8–77%
R2
S
R2
R2
S
R2
R3
R3
S
S
S
S
S
S
a Department of Applied Chemistry, Graduate
School of Science and Engineering, Ehime
University, Matsuyama 790-8577, Japan
misaki.yohji.mx@ehime-u.ac.jp
b Elements Strategy Initiative for Catalysts and
Batteries (ESICB), Kyoto University, Katsura,
Kyoto 615-8520, Japan
S
S
X
R1
S
S
X
X
R3
R3
S
S
S
S
S
S
R1
S
S
S
S
S
S
R2 = CO2Me, SMe, Sn-C6H13
R2–R2 = (CH=CH)2
R3 = Sn-C6H13
R2
R2
R1
R1
R1
R1
67–92%
56–83%
39–81%
Received: 30.10.2015
Accepted after revision: 14.12.2015
Published online: 11.01.2016
type formylation of bis(dithiafulvenyl) derivatives 1 afford-
ed the corresponding monoformylated derivatives 2 in high
yields.5 When the similar reaction was applied to dithienyl
derivatives 3, formylation at the 5-position of the thiophene
ring proceeded efficiently to give dialdehydes 46 (Figure 1).
DOI: 10.1055/s-0035-1560400; Art ID: ss-2015-f0634-op
Abstract The Vilsmeier–Haack type formylations on various 6-aryl-
1,4-dithiafulvenes were examined. The furyl derivatives on treatment
with an excess of POCl3 in DMF at room temperature mainly afforded
dialdehydes substituted at the 6-position and the furan ring, while the
thienyl derivatives and the phenyl derivatives mainly gave monoformy-
lated derivatives substituted at the 6-position. The obtained mono- and
dialdehydes were converted into monoaryl-substituted 2,2′-eth-
anediylidene-bis(1,3-dithiole) derivatives and heteroaromatic ring-in-
serted [3]dendralene derivatives with triple 1,3-dithiol-2-ylidenes and
their TTF-fused analogues. Electrochemical properties of the new π-
electron donors were also investigated by cyclic voltammetry.
R2
S
R1
R1
R1
R1
S
S
R2
S
S
R1
R1
R1
R1
S
S
S
S
1, R2 = H
2, R2 = CHO
S
3, R2 = H
4, R2 = CHO
R2
Key words tetrathiafulvalene, redox, cyclic voltammetry, Vilsmeier–
Haack reaction, heterocycles
Figure 1 Bis(dithiafulvenyl) derivatives
Tetrathiafulvalene (TTF) analogues with extended π-
conjugation have received current attention as the compo-
nents for organic electronic materials such as molecular
conductors, organic field effective transistors (OFET), pho-
tovoltaic devices, nonlinear optic (NLO) materials, re-
chargeable batteries, and so on.2,3 A number of extended-
TTF systems have been synthesized by means of Wittig or
Horner–Wadsworth–Emmons type reactions with 6-
formyl-1,4-dithiafulvenes.2a Phosphite-mediated cross-cou-
pling between 6-formyl-1,4-dithiafulvenes and 1,3-dithi-
ole-2-thiones is also utilized.4 1,4-Dithiafulvenes with one
or more formyl groups are of interest as precursors for ex-
tended TTF donors showing multi-electron redox property.
The Vilsmeier–Haack type formylation on aromatic ring is
known as a versatile methodology for the preparation of
aryl aldehydes. We have reported that the Vilsmeier–Haack
In the case of the Vilsmeier–Haack type formylations on
6-aryl-1,4-dithiafulvenes 5, the formation of three prod-
ucts, that is, monoaldehydes 6 and 7 in which one formyl
group is introduced at the 6-position or the aromatic ring,7,8
respectively, and the bis-formylated product 8 is expected.
These aldehydes can be utilized as precursors for the syn-
thesis of monoaryl-substituted bis(dithiafulvenyl) deriva-
tives 9, extended TTF analogues incorporating aromatic π-
electron spacer 10,7,9 and [3]dendralene-type TTF ana-
10
logues 11 incorporating an aromatic spacer (Scheme 1).
There is no report on the synthesis of 9, although diaryl an-
alogues such as 3 have been often prepared by the oxidative
coupling of 5 followed by reduction accompanied dehydro-
gen process.11 The aldehydes 7 can be easily prepared from
bis(formyl)-substituted aromatic compounds. However,
© Georg Thieme Verlag Stuttgart · New York — Synthesis 2016, 48, A–J

B
A. Fujioka et al.
Paper
Synthesis
1
S
2
3
R
R
X
T, X = S
F, X = O
B, X = (CH=CH)
a, R = CO2Me
b, R = SMe
6
5
CHO
X
S
5
4
CHO
X
CHO
R
R
R
S
S
X
R
S
X
S
CHO
S
R
CHO
S
R
7
6
8
R
R
S
S
R
R
S
S
X
X
R
R
S
S
X
S
S
R
S
S
9
S
S
S
S
R
R
R
10
R
R
R
R
11
Scheme 1 Synthetic routes to extended TTF systems
2,5-bis(formyl)thiophene is very expensive compared with
2-formylthiophene. Furthermore, 2,5-bis(formyl)furan is
not commercially available and its synthesis is more diffi-
cult than the synthesis of 2,5-bis(formyl)thiophene. The
thiophene analogue of 7 has been also utilized as an im-
portant precursor of multi-fused TTF type donors 1212 (Fig-
ure 2). The dendralene-type donors 11 are of interest as
multistage redox systems because of their cross π-conjuga-
tion mode in addition to interest as donor components for
molecular conductors with novel molecular arrangement.10
In this paper, we report Vilsmeier–Haack type formyla-
tions on 6-aryl-1,4-dithiafulvenes, and syntheses of various
π-electron donors, particularly dendralene-type donors
with aromatic rings inserted by using the formylated prod-
ucts as the precursors. Electrochemical properties of the π-
electron donors newly synthesized are also reported.
only the product 6Ta formylated at the 6-position in a high
yield of 94% (Table 1, entry 1). When two equivalents of
POCl3 was used, small amount of the bisformylated product
8Ta was obtained (9% yield) together with the main product
6Ta (77%, entry 2). The yield of 8Ta was a little enhanced
when the amount of POCl3 was increased. In all cases, the
monoformylated product on the thiophene ring 7Ta was
not obtained at all.
Next, the formylation of bis(methylthio) derivative 5Tb,
and the 6-aryl-1,4-dithiafulvenes in which the 6-position is
substituted by the other aryl group of furyl or phenyl
group, was examined (see Table 2). The bis(methylthio) de-
rivative 5Tb predominantly afforded 6Tb in ca. 90% yield
similar to 5Ta (Table 2, entries 1–3). The yield of 8b im-
proved considerably (67%) by raising the reaction tempera-
ture up to 80 °C (entry 4), although increase of POCl3 had
little effect on the yield of 8Tb (entry 3). When the furyl de-
rivative 5Fa was treated with an equimolar amount of
POCl3, a monoformylated product 7Fa was predominantly
obtained in 56% yield together with 6Fa (10% yield) and 8Fa
(13% yield). In the reaction using the bis(methylthio) deriv-
Firstly, the formylation on 6-thienyl-2,3-bis(methoxy-
carbonyl)-1,4-dithiafulvene (5Ta)13 was examined by treat-
ment with POCl3 in DMF and then with aqueous sodium hy-
droxide solution. The results are summarized in Table 1.
The reaction of 5Ta with equimolar amount of POCl3 gave
S
S
R
R
S
S
S
S
S
S
S
S
S
R
S
S
S
S
R
n – 2
12
Figure 2 Multi-fused TTF donors extended with thiophene spacers
n = 3–5, 7
© Georg Thieme Verlag Stuttgart · New York — Synthesis 2016, 48, A–J

C
A. Fujioka et al.
Paper
Synthesis
Table 1 Formylation of 5Ta
CHO
+
CHO
MeO2C
MeO2C
MeO2C
MeO2C
MeO2C
MeO2C
S
S
S
S
S
S
S
S
S
S
S
S
1) POCl3/DMF
2) NaOH/H2O
+
CHO
CHO
MeO2C
MeO2C
5Ta
6Ta
7Ta
8Ta
Entry
Equiv of POCl3
Time (h)
Yield (%)
6Ta
7Ta
8Ta
1
2
3
4
5
6
7
1
2
2
4
4
8
8
6
6
94
77
84
64
78
74
80
0
0
0
0
0
0
0
0
9
12
6
8
9
12
6
11
11
13
12
ative 5Fb, the yield of 6Fb (34%) was comparable to that of
7Fb (40%), and 8Fb was not obtained at all. The bisformylat-
ed products 8F were obtained as the main products (>70%
yield), when more excess amount (8 equiv mol) of POCl3
was used (entries 6 and 8). In the cases of the phenyl deriv-
atives 5Ba and 5Bb, only the corresponding derivatives of 6,
6Ba, and 6Bb, were obtained in high yields (>90%).
The selectivity of the formylation of 5 might be ex-
plained by difference in stability between plausible inter-
mediates 13 and 14, which conduct to the products 6 and 7,
respectively, as shown in Figure 3. A positive charge on the
1,3-dithiolylium ring of 14 can be delocalized over the aro-
matic ring, while that of 13 cannot be delocalized over
there. However, aromaticity of the aryl group is lost when
the positive charge is distributed over the aryl group. The
order of aromaticity is as follows: benzene > thiophene >
furan. As for the phenyl and thienyl derivatives with strong
aromaticity, stabilization by aromaticity might be superior
to stabilization by delocalization of the positive charge. As a
result, 13B and 13T are more stable than 14B and 14T, lead-
ing to the formation of 6B and 6T predominantly. As for the
Table 2 Formylation of 5Tb, 5Fa, 5Fb, 5Ba, and 5Bb
CHO
+
CHO
R
R
R
R
R
R
R
R
S
S
X
S
S
S
S
X
S
S
X
X
1) POCl3/DMF
2) NaOH/H2O
+
CHO
CHO
5
6
7
8
Entry
Compd
X
R
Equiv
Temp
(°C)
Time (h)
Yield (%)
of POCl3
6
7
8
1
2
5Tb
5Tb
5Tb
5Tb
5Fa
5Fa
5Fb
5Fb
5Ba
5Bb
S
SMe
1
8
r.t.
r.t.
r.t.
80
r.t.
r.t.
r.t.
r.t.
r.t.
r.t.
12
12
12
12
12
12
12
12
12
12
91
89
90
14
10
3
0
0
0
0
0
3
S
SMe
3
S
SMe
16
16
1
2
4
S
SMe
67
13
77
0
5
O
O
O
O
CO2Me
CO2Me
SMe
56
6
8
2
40
16
0
7
1
34
0
8
SMe
8
76
0
9
CH=CH
CH=CH
CO2Me
SMe
8
93
97
10
8
0
0
© Georg Thieme Verlag Stuttgart · New York — Synthesis 2016, 48, A–J

D
A. Fujioka et al.
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Synthesis
tron-withdrawing effect, 14Fa might be considerably more
stable than 13Fa, while 14b is slightly more stable than
13Fb.
R
R
S
X
+
N+
The monoformylated products 6 can be converted to the
corresponding derivatives of 9 by two methods as shown in
Scheme 2. One is the Wittig reaction with 1513 in the pres-
ence of triethylamine or LDA. The other is the triethyl phos-
phite-mediated cross coupling with 1,3-dithiole-2-thiones
16. The reaction of 6Ba and 6Ta with 15a in the presence of
an excess of triethylamine gave 9Ba and 9Ta in 50 and 65%
yield, respectively. The furyl derivative 9Fa was obtained in
78% yield by the reaction of 6Fa with 15a in the presence of
LDA in THF at –78 °C. On the other hand, 6Ba,b, 6Tb, and
6Fb were cross-coupled with 16a,b mediated by triethyl
phosphite in refluxing toluene to afford the corresponding
9 in 39–81% yields.
S
H
H
13
H
+
N+
N+
R
R
R
R
S
+
S
S
X
X
S
14
Figure 3 Plausible structures of intermediates of 6 and 7
MeO2C
S
+
PBu3
–
S
MeO2C
PF6
15a
R
R
The dialdehydes 8 were converted to analogous [3]den-
dralene derivatives with triple 1,3-dithiol-2-ylidenes, in
which a heteroaromatic ring is inserted (Scheme 3). Treat-
ment of 8Ta and 8Fa with 15a in the presence of an excess
of triethylamine in THF at room temperature gave hex-
akis(methoxycarbonyl) derivatives 11Ta and 11Fa in 56 and
70% yield, respectively. On the other hand, the hex-
akis(methylthio) derivatives 11Tb and 11Fb were obtained
in the respective yields of 75 and 63% by using the Horner–
Wadsworth–Emmons reaction with 17b14 in the presence
of n-BuLi in THF at –78 °C. The compounds 11Tb and 11Fb
were also prepared in 42 and 82% yield, respectively, by tri-
ethyl phosphite mediated cross-coupling reaction between
8T(F)b and 16b in refluxing toluene.
When the dialdehyde 8Fb was treated with an equimo-
lar amount of the phosphonium salt 15a in the presence of
n-BuLi, the 1,3-dithiol-2-ylidene unit was selectively at-
tached on the furan ring to form 18 in 75% yield as shown in
Scheme 4. The reaction of 18 with 17c15 in the presence of
n-BuLi gave 11Fc in 83% yield (Scheme 4). By using this
methodology, various derivatives of 11 with different sub-
stituents from each other might be synthesized at will. On
the other hand, the Horner–Wadsworth–Emmons reaction
of 8Ta,b, 8Fa, and 8Fb with a phosphonate fused with TTF
Et3N or LDA
S
S
THF
r.t or –78 °C
X
R
R
S
S
X
R
R
S
S
S
S
S
CHO
, P(OEt)3
6Ba, 6Bb
6Ta, 6Tb
6Fa, 6Fb
16a,b
R
R
9Ba, 9Bb
9Ta, 9Tb
9Fa, 9Fb
toluene
reflux
Scheme 2 Synthesis of 9
furyl derivatives, 14F might be more stable than 13F due to
more effective overlap between C2p and O2p orbitals than
overlap between C2p and S3p ones as well as small aroma-
ticity of furan. As a result, the yields of 7F might be higher
than those of 6F (entries 5 and 7). When an equimolar
amount of POCl3 was used, 7Fa was obtained more selec-
tively than 7Fb. Density of the positive charge on the 1,3-
dithiole ring of 14 is lower than that of 13 because of the
resonance effect as mentioned above. Considering the elec-
O
MeO2C
MeS
S
S
+
or
PBu3
P(OEt)2
17b
, BuLi
R
R
–
S
PF6
S
MeO2C
MeS
15a
, Et3N
S
S
THF
r.t. or –78 °C
CHO
R
R
X
S
S
X
MeS
MeS
S
CHO
S
S
S
S
S
, P(OEt)3
S
8Ta, 8Fa
8Tb, 8Fb
16b
R
R
R
R
toluene
reflux
11Ta, 11Fa
11Tb, 11Fb
Scheme 3 Synthesis of 11
© Georg Thieme Verlag Stuttgart · New York — Synthesis 2016, 48, A–J

E
A. Fujioka et al.
Paper
Synthesis
O
MeO2C
MeO2C
S
S
S
S
+
S
S
PBu3
OHC
P(OEt)2
O
–(1 equiv mol), BuLi
, BuLi
PF6
17c
15a
O
8Fb
S
S
S
S
THF
−78 °C
THF
−78 °C
S
S
S
S
E
E
HS
SMe
E
SMe
E
18
MeS
E = CO2Me
11Fc
E = CO2Me
Scheme 4 Synthesis of 11Fc
n-C6H13
n-C6H13
S
S
S
S
S
S
S
S
O
n-C6H13
n-C6H13
S
S
8Ta
8Tb
8Fa
8Fb
S
S
S
S
S
X
n-BuLi
+
P(OEt)2
R
S
S
THF
–78 °C
S
Sn-C6H13
Sn-C6H13
S
S
S
S
S
19
R
S
20Ta, 20Tb, 20Fa, 20Fb
Scheme 5 Synthesis of 20
moiety 1916 in the presence of n-BuLi or LDA in THF at
–78 °C afforded tetrathiapentalene-type extended [3]den-
dralenes, 20Ta,b, 20Fa, and 20Fb in 67–93% yields (Scheme
5).
Table 3 Redox Potentials of New Donors 9, 11, and 20a
Compd
E1
+0.23
E2
+0.46
E3
E4
E5
E6
9Ta
9Tb
Electrochemical properties of new donors were investi-
gated by cyclic voltammetry. The redox potentials of 9, 11,
and 20 are summarized in Table 3. All the derivatives of 9
exhibit two pairs of one-electron redox waves similar to 1.
On the other hand, 3 and its phenyl analogue 21 (Figure 4)
are known to show one pair of simultaneous two-electron
transfer wave because of conformational change from the
neutral molecule with a nonplanar extended TTF core to
the oxidative species with a planar extended TTF core.11
These results suggest that the extended TTF core of 9 has a
high planarity, and that no significant conformational
change is accompanied by the oxidation as a result. All the
derivatives of 11 except for 11Fb exhibit three pairs of one-
electron redox waves. The donor 11Fb shows two pairs of
redox waves, of which the first redox wave corresponds to a
two-electron transfer. The TTF-fused donors 20 may exhibit
seven-electron redox, because they have seven redox-active
1,3-dithiol-2-ylidene sites. All the derivatives of 20 exhibit
five pairs of redox waves, one of which corresponds to two-
electron transfer process due to apparent overlap of two
stages of redox processes. The oxidation process corre-
sponding to the formation of 207+ was not observed. This
result suggests that 207+ is significantly destabilized by
large intramolecular Coulomb repulsion ascribed to the
presence of seven positive charges in 207+.
–0.04
+0.11
+0.38
+0.09
+0.36
+0.09
+0.27
9Ba
+0.18
9Bb
–0.07
11Ta
11Tb
11Fa
11Fb
11Fc
20Ta
20Tb
20Fa
20Fb
+0.29
+0.82
–0.03
+0.42
+0.94
+0.54
+0.78
+0.27
+0.16
–0.03 (2e)
+0.01
+0.07
+0.09 (2e)
–0.00
+0.40
+0.57
+0.45
+0.65
+0.14 (2e)
+0.13
+0.42 (2e)
+0.42 (2e)
+0.37
+0.62
+0.63
+0.58
+0.07
+0.23
+0.20
+0.02 (2e)
a In benzonitrile containing 0.1 M n-Bu4NPF6 at 25 °C using Pt working and
counter electrodes with scan rate of 50 mV s–1. All potentials (V) were mea-
sured against Ag/Ag+ electrode and converted to the value vs. Fc/Fc+.
In summary, we have demonstrated that the Vilsmeier–
Haack type formylation of 6-aryl-1,4-dithiafulvenes is a
versatile method for the preparation of the precursors for
1,3-dithiole donors. Various new extended TTF donors,
monoaryl-substituted TTF vinylogues 9, heteroaromatic
ring inserted [3]dendralene derivatives with triple 1,3-
© Georg Thieme Verlag Stuttgart · New York — Synthesis 2016, 48, A–J

F
A. Fujioka et al.
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Synthesis
6Tb
Obtained in 91% yield (290 mg, 0.91 mmol) from 5Tb after column
chromatography (SiO2, CH2Cl2) (entry 1 in Table 2); yellow crystals;
mp 94–95 °C.
R
R
S
S
R
S
IR (KBr): 1618, 1499, 1443, 1407, 1314, 1259, 1094 cm–1
.
S
R
1H NMR (400 MHz, CDCl3): δ = 2.45 (s, 3 H), 2.56 (s, 3 H), 7.13–7.18
(m, 2 H), 7.40 (dd, J = 5.2, 1.2 Hz, 1 H), 9.46 (s, 1 H).
21
13C NMR (100 MHz, CDCl3): δ = 18.77, 19.18, 115.29, 125.66, 126.46,
127.55, 133.90, 137.98, 161.62, 183.30.
Figure 4 Bis(6-phenyl-1,4-dithiafulvenyl) derivatives
HRMS (MALDI-TOF): m/z = 317.9335 (calcd), 317.9353 (found).
dithiol-2-ylidenes 11, and their TTF-fused analogues 20
were successfully synthesized by introduction of 1,3-dithi-
ol-2-ylidene units on 6 or 8 using the Horner–Wadsworth–
Emmons reaction or trialkyl phosphite-mediated cross-
coupling reaction. Further investigations, in particular, de-
velopment of functional materials such as molecular con-
ductors and organic rechargeable batteries using 11, 20 and
their related compounds as well as elucidation of detailed
redox processes of 11 and 20, are actively in progress.
6Fa
Obtained in 10% yield (30 mg, 0.09 mmol) from 5Fa after column
chromatography (SiO2, CH2Cl2) (entry 5 in Table 2); yellow powder;
mp 138–139 °C.
IR (KBr): 1738, 1717, 1708, 1648, 1583, 1506, 1420, 1292, 1102, 1024
cm–1
.
1H NMR (400 MHz, CDCl3): δ = 3.92 (s, 3 H), 3.94 (s, 3 H), 6.55–6.56
(m, 2 H), 6.57–6.58 (m, 2 H), 7.54–7.55 (m, 1 H), 9.89 (s, 1 H).
13C NMR (100 MHz, CDCl3): δ = 53.66, 106.40, 111.45, 113.35, 129.89,
136.85, 141.52, 150.08, 153.20, 159.61, 160.24, 183.66.
HRMS (MALDI-TOF): m/z = 325.9919 (calcd), 325.9936 (found).
All solvents and P(OEt)3 used for the reactions were dried and dis-
tilled according to standard procedures. THF for the reactions using
Et3N was exceptionally used without drying. Other commercially
available reagents were used as received. 1H NMR and 13C NMR spec-
tra were recorded on a JEOL NM-EX400 instrument. Spectra are re-
ported (in δ) referenced to Me4Si. Samples were dissolved in CDCl3 or
CS2-C6D6. MS spectra were measured on an Applied Biosystem MALDI
TOFMS Voyager-DETMPRO. Melting points were determined with a
Yanaco MP-J3. Cyclic voltammetry (CV) determinations were record-
ed on an ALS/chi 617BElectrochemical analyzer.
6Fb
Obtained in 34% yield (103 mg, 0.34 mmol) from 5Fa after column
chromatography (SiO2, CH2Cl2) (entry 7 in Table 2); yellow crystalline
needles; mp 49–50 °C.
IR (KBr): 1624, 1573, 1505, 1497, 1437, 1406, 1391, 1365, 1317, 1285,
1270, 1211, 1153, 1117, 1097, 1084, 1033, 1017 cm–1
.
1H NMR (400 MHz, CDCl3): δ = 2.50 (s, 3 H), 2.57 (s, 3 H), 6.50–6.51
(m, 1 H), 6.53–6.54 (m, 1 H), 7.51–7.54 (m, 1 H), 9.79 (s, 1 H).
13C NMR (100 MHz, CDCl3): δ = 18.79, 19.24, 105.87, 111.21, 113.04,
126.42, 134.29, 141.01, 150.56, 157.34, 182.97.
Synthesis of Aldehydes 6–8; Preparation of 8Fb; Typical Proce-
dure17
MS: m/z = 303 (M+).
To a suspension of 5Fb (274 mg, 1.0 mmol) in DMF (20 mL) was added
POCl3 (0.75 mL, 8.0 mmol) at 0 °C. After stirring for 12 h at r.t., aq 1 M
NaOH (16 mL) was added to the reaction mixture at 0 °C. The mixture
was extracted with CH2Cl2, and the combined extracts were washed
with H2O. The organic layer was dried (Na2SO4) and the solvent was
evaporated under reduced pressure. The residue was purified by col-
umn chromatography (SiO2, CH2Cl2) to afford 8Fb (252 mg, 76%, 0.76
mmol) together with 7Fb (52 mg, 16%, 0.16 mmol).
Anal. Calcd for C11H10O2S4: C, 43.68; H, 3.33. Found: C, 43.80; H, 3.51.
6Ba
Obtained in 93% yield (314 mg, 0.93 mmol) from 5Ba after column
chromatography (SiO2, CH2Cl2) (entry 9 in Table 2); yellow crystalline
plates; mp 117–118 °C.
IR (KBr): 1714, 1631, 1578, 1502, 1459, 1432, 1387, 1282, 1105, 1093,
1034 cm–1
.
6Ta
1H NMR (400 MHz, CDCl3): δ = 3.85 (s, 3 H), 3.93 (s, 3 H), 7.38–7.44
(m, 3 H), 7.48–7.52 (m, 2 H), 9.44 (s, 1 H).
13C NMR (100 MHz, CDCl3): δ = 53.45, 53.47, 122.80, 128.22, 128.41,
128.66, 128.83, 129.36, 129.47, 136.02, 136.32, 156.75, 159.49,
160.10, 184.38.
Obtained in 94% yield (126 mg, 0.40 mmol) from 5Ta after column
chromatography (SiO2, CH2Cl2) (entry 1 in Table 1); brown powder;
mp 105–106 °C.
IR (KBr): 1744, 1717, 1704, 1626, 1573, 1455, 1435, 1415, 1287, 1094,
1031 cm–1
.
1H NMR (400 MHz, CDCl3): δ = 3.88 (s, 3 H), 3.94 (s, 3 H), 7.16 (dd, J =
5.2, 3.6 Hz, 1 H), 7.21 (dd, J = 3.6, 1.2 Hz, 1 H), 7.43 (dd, J = 5.2, 0.8 Hz,
1 H), 9.54 (s, 1 H).
HRMS (MALDI-TOF): m/z = 336.0126 (calcd), 336.0128 (found).
6Bb
13C NMR (100 MHz, CDCl3): δ = 53.56, 115.66, 126.24, 126.86, 127.73,
129.32, 136.70, 137.21, 158.19, 159.41, 159.97, 183.96.
Obtained in 97% yield (303 mg, 0.97 mmol) from 5Bb after column
chromatography (SiO2, CH2Cl2) (entry 10 in Table 2); yellow crystals;
mp 85–86 °C.
HRMS (MALDI-TOF): m/z = 341.9690 (calcd), 341.9685 (found).
IR (KBr): 1622, 1490, 1454, 1427, 1417, 1385, 1268 cm–1
.
© Georg Thieme Verlag Stuttgart · New York — Synthesis 2016, 48, A–J

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A. Fujioka et al.
Paper
Synthesis
1H NMR (400 MHz, CDCl3): δ = 2.41 (s, 3 H), 2.56 (s, 3 H), 7.38–7.41
MS: m/z = 331 (M+).
(m, 3 H), 7.46–7.50 (m, 2 H), 9.36 (s, 1 H).
13C NMR (100 MHz, CDCl3): δ = 18.75, 19.12, 122.58, 125.71, 128.26,
Anal. Calcd for C12H10O3S4: C, 43.61; H, 3.05. Found: C, 43.31; H, 3.06.
128.46, 129.29, 133.37, 136.63, 160.17, 183.80, 183.82.
MS: m/z = 312 (M+).
Synthesis of 9Ba; Typical Procedure
To a mixture of 6Ba (168 mg, 0.50 mmol) and 15a (251 mg, 0.50
mmol) in THF (20 mL) was added Et3N (3 mL) at r.t. and the mixture
was stirred at r.t. for 1 h. The mixture was extracted with CH2Cl2. The
combined organic layers were evaporated in vacuo, and the residue
was purified by column chromatography (SiO2, CH2Cl2) to afford 9Ba
(135 mg, 0.25 mmol) in 50% yield; deep red powder; mp 125–126 °C.
IR (KBr): 1740, 1708, 1576, 1432, 1257, 1092, 1036 cm–1
1H NMR (400 MHz, CDCl3): δ = 3.71 (s, 3 H), 3.77 (s, 3 H), 3.80 (s, 3 H),
Anal. Calcd for C13H12OS4: C, 49.97; H, 3.87. Found: C, 49.81; H, 3.93.
8Ta
Obtained in 13% yield (470 mg, 1.27 mmol) from 5Ta after column
chromatography (SiO2, CH2Cl2) (entry 7 in Table 1); yellow powder;
mp 159–160 °C.
.
IR (KBr): 1644, 1556, 1505, 1433, 1258, 1030 cm–1
.
3.85 (s, 3 H), 5.93 (s, 1 H), 7.37–7.44 (m, 5 H).
1H NMR (400 MHz, CDCl3): δ = 3.92 (s, 3 H), 3.96 (s, 3 H), 7.37 (d, J =
4.0 Hz, 1 H), 7.82 (d, J = 4.0 Hz, 1 H), 9.66 (s, 1 H), 9.94 (s, 1 H).
13C NMR (100 MHz, CDCl3): δ = 53.78, 53.79, 114.92, 126.76, 129.34,
136.58, 137.65, 142.73, 147.16, 159.01, 159.77, 159.94, 182.51,
183.05.
13C NMR (100 MHz, CDCl3): δ = 53.09, 53.17, 53.19, 53.24, 111.73,
124.82, 128.85, 129.01, 129.32, 129.53, 129.56, 129.93, 132.02,
132.13, 132.16, 135.69, 159.73, 159.79, 160.04, 160.06.
HRMS (MALDI-TOF): m/z = 537.9885 (calcd), 537.9838 (found).
MS: m/z = 371 (M+).
9Ta
Anal. Calcd for C14H10O6S3: C, 45.39; H, 2.72. Found: C, 45.54; H, 2.82.
Obtained in 65% yield (207 mg, 0.38 mmol) from 6Ta and 15a after
column chromatography (SiO2, CH2Cl2); red crystalline needles;
mp159–160 °C.
8Tb
Obtained in 67% yield (233 mg, 0.67 mmol) from 5Tb after column
chromatography (SiO2, CH2Cl2) (entry 4 in Table 2); orange powder;
mp 133–134 °C.
IR (KBr): 1650, 1444, 1405, 1295, 1229, 1038 cm–1
1H NMR (400 MHz, CDCl3): δ = 2.49 (s, 3 H), 2.59 (s, 3 H), 7.32 (d, J =
4.0 Hz, 1 H), 7.79 (d, J = 4.0 Hz, 1 H), 9.61 (s, 1 H), 9.93 (s, 1 H).
13C NMR (100 MHz, CDCl3): δ = 18.85, 19.35, 114.64, 125.98, 126.86,
IR (KBr): 1732, 1579, 1432, 1257, 1092, 1025 cm–1
.
1H NMR (400 MHz, CDCl3): δ = 3.75 (s, 3 H), 3.81 (s, 6 H), 3.85 (s, 3 H),
5.94 (s, 1 H), 7.02 (d, J = 1.8 Hz, 1 H), 7.09 (t, J = 4.4 Hz, 1 H), 7.41 (d, J =
2.4 Hz, 1 H).
13C NMR (100 MHz, CDCl3): δ = 53.14, 53.22, 53.26, 53.29, 111.76,
116.66, 127.50, 127.85, 128.38, 129.22, 130.55, 131.71, 132.02,
132.05, 134.64, 137.37, 159.68, 159.77, 159.86, 159.99.
.
135.32, 136.68, 141.89, 148.34, 163.31, 182.37, 182.50.
MS: m/z = 347 (M+).
HRMS (MALDI-TOF): m/z = 543.9449 (calcd), 543.9424 (found).
Anal. Calcd for C12H10O2S5: C, 41.59; H, 2.91. Found: C, 41.31; H, 3.05.
9Fa
Obtained in 78% yield (62 mg, 0.12 mmol) from 6Fa and 15a after col-
umn chromatography (SiO2, CH2Cl2); deep red crystalline needles; mp
88–89 °C.
8Fa
Obtained in 77% yield (272 mg, 0.77 mmol) from 5Fa after column
chromatography (SiO2, CH2Cl2) (entry 6 in Table 2); orange powder;
mp 184 °C.
IR (KBr): 1734, 1579, 1434, 1254, 1093, 1028 cm–1
.
1H NMR (400 MHz, CDCl3): δ = 3.79 (s, 3 H), 3.84 (s, 3 H), 3.85 (s, 3 H),
3.86 (s, 3 H), 5.89 (s, 1 H), 6.28 (d, J = 1.6 Hz, 1 H), 6.45 (m, 1 H), 7.50
(m, 1 H).
IR (KBr): 1761, 1743, 1704, 1672, 1644, 1513, 1413, 1343, 1243, 1097
cm–1
.
1H NMR (400 MHz, CDCl3): δ = 3.97 (s, 6 H), 6.79 (d, J = 4.0 Hz, 1 H),
7.39 (d, J = 4.0 Hz, 1 H), 9.68 (s, 1 H), 10.0 (s, 1 H).
13C NMR (100 MHz, CDCl3): δ = 53.80, 53.90, 107.10, 111.54, 131.32,
13C NMR (100 MHz, CDCl3): δ = 53.19, 53.30, 108.87, 110.12, 111.69,
112.52, 130.11, 130.60, 130.78, 131.48, 132.69, 136.90, 142.42,
148.70, 159.83, 159.93.
136.95, 151.24, 155.95, 158.24, 159.34, 159.79, 176.35, 182.64.
HRMS (MALDI-TOF): m/z = 527.9677 (calcd), 527.9680 (found).
MS: m/z = 354 (M+).
Synthesis of 9Bb; Typical Procedure
Anal. Calcd for C14H10O7S2: C, 47.45; H, 2.84. Found: C, 47.32; H, 2.93.
To a mixture of 6Bb (220 mg, 0.70 mmol) and 16b (198 mg, 0.86
mmol) in toluene (7.0 mL) was added P(OEt)3 (7.0 mL) at r.t. The reac-
tion mixture was stirred at 110 °C for 2 h under an argon atmosphere.
After evaporation of the solvent in vacuo, the residue was purified by
column chromatography (SiO2, CH2Cl2) to afford 9Bb (180 mg, 0.37
mmol) in 53% yield; yellow powder; mp 96–97 °C.
8Fb
Obtained in 76% yield (251 mg, 0.76 mmol) from 5Fb after column
chromatography on silica gel (SiO2, CH2Cl2) (entry 8 in Table 2); or-
ange crystalline plates; mp 140–141 °C.
IR (KBr): 1668, 1626, 1557, 1512, 1482, 1392, 1335, 1298, 1042 cm–1
1H NMR (400 MHz, CDCl3): δ = 2.55 (s, 3 H), 2.60 (s, 3 H), 6.71 (d, J =
3.2 Hz, 1 H), 7.37 (d, J = 4.0 Hz, 1 H), 9.63 (s, 1 H), 9.93 (s, 1 H).
13C NMR (100 MHz, CDCl3): δ = 18.84, 19.36, 106.18, 111.10, 128.07,
.
IR (KBr): 1523, 1496, 1481, 1426, 1311 cm–1
.
1H NMR (400 MHz, CDCl3): δ = 2.17 (s, 3 H), 2.31 (s, 3 H), 2.36 (s, 3 H),
2.44 (s, 3 H), 5.99 (s, 1 H), 7.31–7.42 (m, 5 H).
135.51, 150.77, 156.89, 161.97, 175.99, 181.96.
© Georg Thieme Verlag Stuttgart · New York — Synthesis 2016, 48, A–J

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A. Fujioka et al.
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Synthesis
13C NMR (100 MHz, CDCl3): δ = 18.71, 18.76, 18.82, 18.86, 112.04,
124.60, 125.41, 125.99, 126.66, 127.03, 128.27, 129.09, 129.54,
130.11, 132.15, 136.61.
1H NMR (400 MHz, CDCl3): δ = 3.79 (s, 3 H), 3.84 (s, 3 H), 3.86–3.87
(m, 12 H), 5.92 (s, 1 H), 6.25 (d, J = 3.6 Hz, 1 H), 6.35 (d, J = 4.0 Hz, 1 H),
6.37 (s, 1 H).
HRMS (MALDI-TOF): m/z = 489.9174 (calcd), 489.9916 (found).
13C NMR (100 MHz, CDCl3): δ = 53.20, 53.25, 53.27, 53.33, 53.34,
102.79, 109.21, 110.13, 111.34, 112.01, 129.59, 130.02, 130.17,
130.70, 130.80, 131.55, 131.59, 133.04, 137.54, 147.61, 150.70,
159.83, 159.84, 159.85, 159.92, 159.94.
9Tb
Obtained in 81% yield (161 mg, 0.32 mmol) from 6Tb and 16b after
column chromatography on silica gel with CH2Cl2; yellow powder;
mp 110–111 °C.
HRMS (MALDI-TOF): m/z = 757.9385 (calcd), 757.9405 (found).
IR (KBr): 1530, 1510, 1481, 1424, 1309 cm–1
.
Synthesis of 11Tb; Typical Procedure, Method A
To a stirred solution of 8Tb (50 mg, 0.14 mmol) and 17b (140 mg, 0.43
mmol) in anhydrous THF (8 mL) was added dropwise 1.6 M hexane
solution of BuLi (0.36 mL, 0.58 mmol) over 1 h at –78 °C under argon.
After the addition of MeOH, the mixture was extracted with CH2Cl2
(3×). The combined organic layers were washed with H2O, dried
(MgSO4), and the solvent was evaporated in reduced pressure. The
residue was purified by column chromatography (SiO2, CH2Cl2–
hexane, 2:1) to afford 11Tb (76 mg, 0.11 mmol) in 75% yield; brown-
yellow powder; mp 50–51 °C.
1H NMR (400 MHz, CDCl3): δ = 2.25 (s, 3 H), 2.37(s, 3 H), 2.39 (s, 3 H),
2.44 (s, 3 H), 5.99 (s, 1 H), 7.00 (m, 1 H), 7.08 (dd, J = 5.6, 4.0 Hz, 1 H),
7.37 (dd, J = 4.8, 1.2 Hz, 1 H).
13C NMR (100 MHz, CDCl3): δ = 18.78, 18.84, 18.86, 18.90, 112.00,
116.37, 125.41, 126.55, 126.76, 127.37, 127.49, 127.82, 132.54,
134.78, 138.51.
HRMS (MALDI-TOF): m/z = 495.8738 (calcd), 495.8752 (found).
IR (KBr): 1555, 1474, 1420, 1262, 1102 cm–1
.
9Fb
Obtained in 39% yield (55 mg, 0.17 mmol) from 6Fb and 16b after col-
umn chromatography with CH2Cl2; orange powder; mp 90–91 °C.
1H NMR (400 MHz, CDCl3): δ = 2.27 (s, 3 H), 2.38, 2.40 (s, 6 H), 2.44,
2.46 (s, 9 H), 5.98 (s, 1 H), 6.66 (s, 1 H), 6.82 (d, J = 3.2 Hz, 1 H), 6.92 (d,
J = 3.2 Hz, 1 H).
13C NMR (100 MHz, CDCl3): δ = 18.86, 18.90, 19.06, 108.26, 111.84,
116.40, 124.27, 125.24, 125.47, 126.97, 127.40, 127.92, 128.04,
130.85, 132.30, 135.64, 137.09, 141.03.
IR (KBr): 1582, 1520, 1494, 1479, 1425, 1309, 1154, 1107, 1073, 1014
cm–1
.
1H NMR (400 MHz, CDCl3): δ = 2.31 (s, 3 H), 2.40 (s, 3 H), 2.42 (s, 3 H),
2.45 (s, 3 H), 5.93 (s, 1 H), 6.28 (d, J = 2.8 Hz, 1 H), 6.46 (dd, J = 3.2, 2.0
Hz, 1 H), 7.48 (d, J = 1.2 Hz, 1 H).
13C NMR (100 MHz, CDCl3): δ = 18.83, 18.88, 18.92, 19.00, 108.83,
110.21, 111.50, 112.55, 125.49, 126.83, 126.91, 127.59, 132.23,
136.20, 140.39, 141.81, 149.46.
HRMS (MALDI-TOF): m/z = 701.8091(calcd), 701.8104 (found).
11Fb
Obtained in 63% yield (118 mg, 0.17 mmol) from 8Fb and 17b after
HRMS (MALDI-TOF): m/z = 479.8967 (calcd), 479.8994 (found).
column chromatography (SiO2, CH2Cl2); brown powder; mp 47–48 °C.
IR (KBr): 1487, 1418, 1308, 1021 cm–1
.
Synthesis of 11Ta; Typical Procedure
1H NMR (400 MHz, CDCl3): δ = 2.32 (s, 3 H), 2.41 (s, 3 H), 2.43 (s, 3 H),
2.44 (s, 3 H), 2.46 (s, 3 H), 2.47 (s, 3 H), 5.95 (s, 1 H), 6.20 (d, J = 3.6 Hz,
1 H), 6.32 (d, J = 3.2 Hz, 1 H), 6.37 (s, 1 H).
13C NMR (100 MHz, CDCl3): δ = 18.93, 18.96, 19.01, 19.02, 19.05,
102.59, 108.47, 110.22, 111.17, 112.30, 125.53, 126.24, 126.92,
127.14, 127.21, 128.08, 130.86, 131.14, 136.96, 148.12, 150.88.
To a mixture of 8Ta (370 mg, 1.27 mmol) and 15a (1.92 g, 3.81 mmol)
in THF (100 mL) was added Et3N (1.29 g, 12.7 mmol) at r.t. and the
reaction mixture was stirred at r.t. for 2 h. The mixture was extracted
with CH2Cl2. The combined organic layers were washed with H2O and
then dried (Na2SO4). After evaporation of the solvent in vacuo, the
residue was purified by column chromatography (SiO2, CH2Cl2–hex-
ane, 1:1) to afford 11Ta (551 mg, 0.71 mmol) in 56% yield; brown
powder; mp 77–78 °C.
HRMS (MALDI-TOF): m/z = 667.9076 (calcd), 667.9054 (found).
IR (KBr): 1713, 1633, 1581, 1490, 1433, 1252, 1093, 1025 cm–1
.
11Fc
To a stirred solution of 18 (30 mg, 0.05 mmol) and 17c (18 mg, 0.06
mmol) in THF (10 mL) was added 0.5 M LDA (0.13 mL, 0.06 mmol) at
–78 °C under an argon atmosphere. The mixture was stirred for 8 h,
and then was warmed to r.t. After the addition of MeOH, the reaction
mixture was extracted with CH2Cl2. The combined organic layers
were washed with H2O, and dried (Na2SO4), and the solvent was evap-
orated in vacuo. The residue was purified by column chromatography
(SiO2, CH2Cl2) to afford 11Fc (29 mg, 0.04 mmol) in 83% yield; bright
yellow powder; mp 77–78 °C.
1H NMR (400 MHz, CDCl3): δ = 3.77 (s, 3 H), 3.82 (s, 6 H), 3.86, 3.87,
3.88 (s, 9 H), 5.93 (s, 1 H), 6.64 (s, 1 H), 6.86 (d, J = 3.6 Hz, 1 H), 6.95 (d,
J = 4.0 Hz, 1 H).
13C NMR (100 MHz, CDCl3): δ = 53.25, 53.31, 53.36, 53.39, 53.48,
108.64, 111.65, 116.48, 125.22, 128.63, 129.48, 129.72, 130.04,
130.89, 131.81, 131.88, 132.09, 132.11, 135.81, 136.77, 141.27,
159.66, 159.74, 159.85, 159.88, 159.99, 160.03.
HRMS (MALDI-TOF): m/z = 773.9156 (calcd), 773.9146 (found).
IR (KBr): 1720, 1577, 1432, 1259, 1027 cm–1
.
Anal. Calcd for C28H22O12S7: C, 43.40; H, 2.86. Found: C, 43.22; H, 3.06.
1H NMR (400 MHz, CDCl3): δ = 2.44, 2.45 (s, 6 H), 3.84, 3.85 (s, 6 H),
6.00 (s, 1 H), 6.26 (d, J = 3.6 Hz, 1 H), 6.35 (d, J = 3.6 Hz, 1 H), 6.37 (s, 1
H), 7.02–7.24 (m, 4 H).
11Fa
Obtained in 70% yield (70 mg, 0.92 mmol) from 8Fa and 15a after col-
umn chromatography (SiO2, CH2Cl2); red powder; mp 61–62 °C.
13C NMR (100 MHz, CDCl3): δ = 18.82, 18.92, 53.24, 53.31, 103.25,
109.33, 109.88, 110.70, 112.17, 121.21, 121.58, 125.49, 125.56,
126.98, 128.06, 128.30, 130.48, 131.86, 132.13, 135.37, 136.93,
138.49, 149.02, 150.12, 160.02, 160.04.
IR (KBr): 1730, 1644, 1581, 1433, 1254, 1094, 1027 cm–1
.
© Georg Thieme Verlag Stuttgart · New York — Synthesis 2016, 48, A–J

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A. Fujioka et al.
Paper
Synthesis
HRMS (MALDI-TOF): m/z = 667.9076 (calcd), 667.9054 (found).
IR (KBr): 2954, 2925, 2853, 1560, 1509, 1464, 1260, 1093 cm–1
.
1H NMR (400 MHz, CDCl3): δ = 0.86–0.91 (m, 12 H), 1.28–1.67 (m, 32
H), 2.38 (s, 3 H), 2.45 (s, 3 H), 2.77–2.84 (m, 8 H), 6.07 (s, 1 H), 6.76 (s,
1 H), 6.84 (d, J = 4.0 Hz, 1 H), 6.93 (d, J = 3.6 Hz, 1 H).
13C NMR (100 MHz, CDCl3): δ = 14.04, 19.00, 22.55, 28.20, 28.21,
29.71, 29.72, 31.32, 36.43, 36.46, 111.15, 112.79, 114.98, 115.18,
125.20, 127.28, 127.64, 127.81, 127.90, 128.00, 128.07, 135.92,
140.47.
Synthesis of 11Tb; Typical Procedure, Method B
To a mixture of 8Tb (100 mg, 0.29 mmol) and 16b (323 mg, 1.44
mmol) in toluene (6.3 mL) was added P(OEt)3 (6.3 mL) at r.t. The reac-
tion mixture was stirred at 110 °C for 2 h under an argon atmosphere.
After evaporation of the solvent in vacuo, the residue was purified by
column chromatography (SiO2, CH2Cl2) to afford 11Tb (86 mg, 0.12
mmol) in 42% yield.
MALDI-TOF-MASS: m/z = 1333.8986 (calcd), 1333.8982 (found).
11Fb
20Fa
Obtained in 82% yield (281 mg, 0.42 mmol) from 8Fb and 16b after
Obtained in 72% yield (136 mg, 0.10 mmol) from 8Fa and 19 after col-
umn chromatography on silica gel with (SiO2, CH2Cl2–hexane, 1:1);
brown powder; mp 62–63 °C.
column chromatography (SiO2, CH2Cl2).
Synthesis of 18
IR (KBr): 2953, 2925, 2853, 1730, 1580, 1458, 1433, 1256, 1027 cm–1
.
To a stirred solution of 8Fb (47 mg, 0.14 mmol) and 15a (77 mg, 0.14
mmol) in THF (10 mL) was added 0.5 M LDA (0.28 mL, 0.14 mmol) at
–78 °C under an argon atmosphere and the mixture was stirred for
2 h, and then was warmed to r.t. The mixture was then extracted with
CH2Cl2. The combined organic layers were washed with H2O and dried
(Na2SO4), and the solvent was evaporated in vacuo. The residue was
purified by column chromatography (SiO2, CH2Cl2) to afford 18 (61
mg, 0.11 mmol) in 75% yield; red powder; mp 151–153 °C.
1H NMR (400 MHz, CDCl3): δ = 0.87–0.91 (m, 12 H), 1.29–1.64 (m, 32
H), 2.78–2.83 (m, 8 H), 3.87 (s, 6 H), 6.02 (s, 1 H), 6.23 (d, J = 3.2 Hz, 1
H), 6.36 (d, J = 3.6 Hz, 1 H), 6.47 (s, 1 H).
13C NMR (100 MHz, CDCl3): δ = 14.00, 22.51, 28.17, 28.18, 29.67,
29.69, 31.27, 31.28, 36.39, 36.42, 53.35, 53.39, 104.91, 109.21, 111.62,
111.99, 112.47, 112.79, 112.99, 113.49, 114.20, 115.69, 115.95,
116.50, 127.78, 127.90, 127.99, 128.05, 130.36, 131.24, 132.64,
136.54, 144.29, 147.69, 150.50, 159.82, 159.87.
IR (KBr): 1730, 1703, 1634, 1577, 1431, 1287, 1268, 1030 cm–1
.
HRMS (MALDI-TOF): m/z = 1341.9570 (calcd), 1341.9572 (found).
1H NMR (400 MHz, CDCl3): δ = 2.52 (s, 3 H), 2.58 (s, 3 H), 3.86, 3.87 (s,
6 H), 6.30 (d, J = 3.6 Hz, 1 H), 6.40 (s, 1 H), 6.58 (d, J = 3.6 Hz, 1 H), 9.87
(s, 1 H).
20Fb
13C NMR (100 MHz, CDCl3): δ = 18.83, 19.15, 53.34, 102.87, 108.29,
108.76, 112.62, 127.04, 128.68, 130.52, 131.52, 134.03, 149.42,
150.19, 156.26, 159.87, 159.95, 182.84.
Obtained in 67% yield (134 mg, 0.10 mmol) from 8Fb and 19 after col-
umn chromatography (silica gel with CS2); orange powder; mp 48–
49 °C.
IR (KBr): 2952, 2923, 2852, 1459, 1429 cm–1
.
HRMS (MALDI-TOF): m/z = 531.9271 (calcd), 531.9297 (found).
1H NMR (400 MHz, CDCl3): δ = 0.87–0.91 (m, 12 H), 1.25–1.62 (m, 32
H), 2.45 (s, 3 H), 2.46 (s, 3 H), 2.78–2.84 (m, 8 H), 6.05 (s, 1 H), 6.24 (d,
J = 4.0 Hz, 1 H), 6.33 (d, J = 3.6 Hz, 1 H), 6.47 (s, 1 H).
13C NMR (100 MHz, CDCl3): δ = 14.00, 14.02, 18.97, 19.00, 22.51,
22.52, 28.17, 28.19, 29.67, 29.69, 31.27, 31.28, 31.30, 36.39, 36.41,
105.11, 109.22, 111.23, 111.36, 113.07, 113.29, 114.04, 115.58,
115.87, 126.94, 127.78, 127.90, 127.99, 128.02, 128.38, 135.70,
142.38, 150.06.
Synthesis of 20Ta; Typical Procedure
To a stirred solution of 8Ta (50 mg, 0.14 mmol) and 1916 (210 mg, 0.32
mmol) in THF (10 mL) was added 0.5 M LDA (0.65 mL, 0.32 mmol) at
–78 °C under an argon atmosphere and the mixture was stirred for
8 h, and then was warmed to r.t. After the addition of MeOH, the
mixture was extracted with CH2Cl2. The combined organic layers
were washed with H2O, dried (Na2SO4), and the solvent was evaporat-
ed in vacuo. The residue was purified by column chromatography
(SiO2, CH2Cl2–hexane, 1:1) to afford 20Ta (132 mg, 0.10 mmol) in 72%
yield; red powder; mp 48–49 °C.
HRMS (MALDI-TOF): m/z = 1317.9215 (calcd), 1317.9190 (found).
IR (KBr): 2953, 2925, 2853, 1730, 1579, 1433, 1257, 1092, 1027 cm–1
.
Acknowledgment
1H NMR (400 MHz, CDCl3): δ = 0.88–0.89 (m, 12 H), 1.29–1.65 (m, 32
H), 2.77–2.84 (m, 8 H), 3.82 (s, 3 H), 3.86 (s, 3 H), 6.04 (s, 1 H), 6.76 (s,
1 H), 6.84 (d, J = 4.0 Hz, 1 H), 6.95 (d, J = 3.2 Hz, 1 H).
13C NMR (100 MHz, CDCl3): δ = 14.00, 22.51, 28.18, 29.67, 29.69,
31.28, 36.40, 36.43, 53.31, 53.33, 110.87, 112.64, 112.96, 113.18,
113.71, 115.03, 115.18, 115.81, 116.22, 116.34, 116.37, 125.18,
127.81, 127.85, 127.98, 128.07, 128.78, 130.83, 131.97, 132.11,
136.61, 136.86, 141.12, 142.21, 159.67, 159.81.
This work is partially supported by a Grant-in-Aid for Scientific Re-
search (Nos. 20110006, and 23550155) from the Ministry of Educa-
tion, Culture, Sports, Science and Technology (MEXT), Japan, MEXT
program ‘Elements Strategy Initiative to Form Core Research Center’
(since 2012), Japan Society for the Promotion of Science, and by JST
ALCA program.
MALDI-TOF-MASS: m/z = 1357.9342 (calcd), 1357.9357 (found).
Supporting Information
Supporting information for this article is available online at
20Tb
http://dx.doi.org/10.1055/s-0035-1560400.
S
u
p
p
o
nrtogI
f
rmoaitn
S
u
p
p
ortiInfogrmoaitn
Obtained in 93% yield (173 mg, 0.13 mmol) from 8Tb and 19 after col-
umn chromatography (SiO2, CS2); orange powder; mp 52–53 C.
© Georg Thieme Verlag Stuttgart · New York — Synthesis 2016, 48, A–J

J
A. Fujioka et al.
Paper
Synthesis
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© Georg Thieme Verlag Stuttgart · New York — Synthesis 2016, 48, A–J